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Stream Geomorphic Assessment

1. Data Entry Use the check box in the database to indicate whether the belt width meander width ratio and associated impacts for the reach were determined during a Phase 3 assessment 6 6 WAVELENGTH RATIO Data Sources 1990 series 1 5000 orthophotos digital or hard copy Background Like the meander width ratio the wavelength ratio can also change radically within a reach due to chan nel constriction from floodplain encroachment surficial and bedrock geology small changes in valley slope and other factors see Figure 6 7 Unconfined gravel based streams in shallow sloped valleys have wavelengths generally in the range of 10 to 12 times the width of the channel Leopold 1994 and Williams 1986 Higher values may indicate that the stream has become straighter and steeper possibly degrading its bed and losing access to its floodplain Lower values may indicate that the stream possibly due to an increase in fine sediment has started to aggrade and become more sinuous decreasing its chan nel slope as it migrates laterally Evaluation This parameter is only evaluated for those reaches you typed in Step 2 10 as C or E riffle pool or ripple dune reference stream types in narrow NW and unconfined BD and VB valleys For these reaches calculate the wavelength ratio WLR by dividing the wavelength Lm by the bankfull channel width Worf determined in step 2 8 For reaches that have been straightened for more t
2. 4h Ie Of z lo Q ed Increase hannel width la _ channel depth mean flow velocity Drainage Area downstream distance Figure 1 1 Confined narrow and broad valley types from the Stream Corridor Restoration Manual Federal Interagency Stream Restoration Working Group 1998 With these valley types in mind take a first cut at defining reaches based on the following reach defining characteristics generally listed in order of priority stream confinement or valley width valley slope geologic materials and tributary influence described below Evaluation Use the USGS 1 24 000 topographic maps overlain with the Vermont Hydrography Dataset VHD 1 5 000 stream layer to do this evaluation There are no measurements taken during this first cut of defin ing reaches Itis based solely on the visual differences you observe for the different reach defining char acteristics as seen on the maps You may refine and or change the reaches as you begin taking measure ments in Step 2 Before you formally label the map with the reach numbers complete the Watershed Orientation de scribed at the end of this section and Step 2 to see if any of your reach determinations will need to be refined You may decide as you start measuring the various parameters in Step 2 that some reaches should be combined or separated If you are using SGAT however which automates most of the Step 2 meas urements you will likely n
3. ally channels in steep confined valleys have low sinuosity and channels in broad gentle sloped valleys have high sinuosity Reach breaks may be appropriate where there is a significant change in valley slope and confinement as indicated by a channel s sinuosity Figure 1 4 Caution is recommended however in using sinuosity as the basis for making a reach break especially in those situations where the straight ness of the channel may be explained by changes in land use or modifications to the channel valley or floodplain Do not make a separate reach for a section of a stream within a valley of similar characteris tics based solely on a change in the channel sinuosity If for instance a high sinuosity stream within a broad gentle sloped valley becomes straight low sinuosity for a short distance and then becomes sinu ous again do not create a separate reach if the straighter reach cannot be explained by differences in local soils and or geology as determined in Step 3 Wider more gentle sloped valley with a more sinuous channel E y Figure 1 3 Reach break due to a change in valley slope and confinement as indicated by a change in the channel sinuosity Narrower slightly steeper valley with a less sinuous channel Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 10 April 2004 Evaluating Geologic Materials A major change in the erodibility of soils or geologic materials along the stream
4. Comm D R C SAW ate DEAS andiphotos Sediment storage Familiarize self with how sediment deposits appear on orthophotos 63 Mid channel bar Mbr Map locations and types of any observed sediment deposits not Point bar Pbr viewable on orthophotos Delta bar Dtbr Make good field maps Take the field copies of your topographic maps and orthophotos with you on the orientation Record the watershed features and characteristics you observe on your maps and orthopho tos You can use the maps to record new features that are not visible on the maps photos and to verify those features that are visible on the maps photos Reference the field maps when completing the rest of the assessment Standard map codes for field mapping are provided in Table II 2 See Appendix A for additional map codes and symbols Using a GPS You may choose to use a handheld GPS Global Positioning System unit to document feature locations that can later be imported into GIS software as a data layer This is particularly useful in recording grade control and valley wall toe locations that are not apparent on the topographic maps but are obvious in the field You can then use these GPS points later to create digital data layers of grade controls and valley walls the latter of which can be used in the SGAT program Depending on how you plan to use the data you may or may not need the greater level of accuracy that GPS can provide Using a GPS unit is not required fo
5. FEMA National Flood Insurance Town Clerks Dept of Emergency Management Program NFIP maps DEC Division of Water Quality 802 241 3770 Soil Surveys Natural Resources Conservation Service NRCS 802 951 6796 Wetland maps DEC Division of Water Quality 802 241 3770 Getting Started Read the Handbooks Each member of your assessment team should read the Phase 1 Handbook before getting started The team member s running SGAT should read the SGAT manual Understanding the entire protocol and the rationale behind it can save a lot of questions that will undoubtedly arise otherwise Contact the ANR It is highly recommended that you set up a project scoping meeting with the DEC River Management Program before beginning an assessment This offers several advantages finding out whether there have been updates of the protocols or database receiving information on Phase 1 assessment training opportu Phase 1 Stream Geomorphic Assessment April 2004 VT Agency of Natural Resources 4 nities receiving data quality assurance QA assistance and learning about other assessments that may have occurred or are currently underway in your study area It is critical that you contact ANR to find out about other assessments in your watershed as you need to coordinate your reach numbering assignments with prior assessments completed upstream or downstream from where you plan to work Have a Scoping Meeting
6. It also provides an on the ground look at parameters that you will later assess from maps and orthophotos al lowing you to calibrate your eye as to how features you see on the ground appear on the maps and ortho photos The types of information that may be collected during the orientation are listed in the table below The Phase 1 protocol step number is listed next to each parameter and the Notes column sug gests what to look for during the orientation First read the Phase 1 protocols Before starting the watershed orientation overview the protocols pay ing particular attention to the parameters listed in the table below so you know which features are impor tant to note during the watershed orientation For example reading Steps 1 and 2 and Appendices D and E will help you successfully identify valley wall features on the topographic map The Watershed Orientation is not intended to be an exhaustive survey of the entire watershed that cap tures all notable features in the watershed Spend as much time as you can but do not expend so much time that it keeps you from completing the rest of the assessment For example it is not expected that you will see every mile of stream in your watershed and record all grade controls present The Wind Phase Stream Geomorphic Assessment Vermont Agency of Natural Resources 13 April 2004 shield Survey in Phase 1 Step 7 and Phase 2 assessments are designed to confirm Phase 1 observations an
7. i e remote sensing versus field verified data It is also important to make a copy of the original Phase 1 database tables before making revisions based on Phase 2 Phase 3 assessments This will enable your assessment team and ANR staff to improve the accuracy of Phase 1 protocols by tracking the type and frequency of field related changes Everyone who attempts to use your Phase 1 data will appreciate the efforts made to document its quality including its deficiencies If you encounter problems with incomplete data for certain parameters make hard copy and database notes that can be found and considered later It is amazing what just a few months let alone years can do to the collective memories of your assessment team Before beginning a Phase 1 assessment read the QA protocol at the end of the Phase 1 Handbook to more fully understand the data documentation process After the Phase assessment steps are com pleted the QA sheet and QA data entry form in the database Appendices A and B should be completed The QA sheet is a set of questions that documents which steps were completed and when what assess ment tools and data sources were used the level of training received by members of the assessment team and the confidence level of the assessors towards the data collected at each assessment step These QA sheets should be reviewed and finalized by the QA team When data is updated or changed the same process of data review should to be
8. modifications may have altered the channel geometry such that the stream is not in balance with the flow and sediment produced in its watershed Prior to updating the Phase 1 database to reflect field conditions the provisional Phase 1 reach conditions derived using the described database queries and reports may be compared with observations of reach condition made in the field using Phase 2 Rapid Geomorphic Assessment protocols i e it may not be appropriate to compare Phase 1 reaches with Phase 2 segments The database generated report Phase 1 versus Phase 2 adjustment process comparison provides an easy comparison of this data Figure 9 2 Phase 1 Data Phase 2 Data Piese Phase 2 Adjustment Process Fase 2 Condition f type Condition VB C E Aggradation slight but in equilib Good E Aggradation amp Widening slight but Good rium in equilibrium Phase 1 Adjustment Process Planform moderate to major ad Planform moderate to major Fair C i Fair justment adjustment Widening amp Aggradation moderate to r C j Fair major adjustment M19 14 VB C Multiple moderate degradation Fair F Aggradation major adjustment Poor Figure 9 2 Comparison of Phase 1 provisional and Phase 2 RGA Stream Geomorphic Conditions Within the adjustment process column the information in the parentheses is an indication of the severity Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resou
9. nesses such as relatively soft geologic units bedding and other layering within the rock units and frac tures in the rock such as faults or joints Thus a straight reach constrained by bedrock may owe its shape to a fault in the underlying rocks and a sharp bend in the stream may be due to one or more joints in the rock Such fractures can provide an easy path for the stream to follow because the rock weathers faster along the fractures Under present stream flow conditions bedrock controlled streams in Vermont are essentially fixed in position even when viewed over time frames of a hundred years or longer Reaches underlain by surficial deposits can in contrast respond to changing watershed inputs over very short time periods A single flood may drastically alter such a channel and the stream may be able to re spond to the new conditions over a period of months years or decades in order to reestablish the dynamic equilibrium described in the Program Introduction Evaluation Step 3 will help you to make the distinction between bedrock and non bedrock dominated stream systems and to subdivide the non bedrock systems based on the erodibility of the materials in the bed and banks You will also note features that control or accentuate certain erosion processes such as grade controls and the steepness of valley side slopes It is recommended that you work with a geologist or soil scientist to evaluate changes in the erodibility of different soils
10. C stream types Only set the provisional reference stream type as a D Braided channel after observing a braided channel on the topographic maps orthophotos or windshield survey or based on the presence of an alluvial fan see Step 3 1 Only choose the E stream type rather than C where sinuosity values are greater than 1 5 and where windshield survey observa tions support this stream type assignment Data Entry The Phase 1 database contains menus to choose from the full complement of stream type descriptors used in the Rosgen 1996 and Montgomery Buffington 1997 classification schemes This way further de tails of reference stream characteristics determined later in Phase 2 or Phase 3 field assessments can be incorporated in the Phase 1 watershed wide database For instance during a Phase 1 assessment you may provisionally set the reference stream type of a reach as B Plane bed Then in the field you may de termine that the dominant bed material type of the reference condition is cobble sized In this case you would want to revise the reference reach stream type to a B3 Plane bed Dominant bed material and bed form parameter menus are included in the Step 7 Windshield Survey Use the check box in the database to indicate whether the reference stream type for the reach was refined or changed based on windshield surveys or Phase 2 or Phase 3 assessments If you change the reference stream type based on field observation
11. GIS ArcView software Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources 7 April 2004 2 2 VALLEY LENGTH SGAT Data Sources e USGS 1 24 000 topographic maps hard copy or digital Vermont Hydrography Data Set VHD 1 5 000 stream coverage if you don t have access to this coverage use the surface waters on the USGS 1 24 000 topographic maps Evaluation Read section 2 4 channel length to understand the difference between measuring valley length and channel length Measure the length of the valley in feet by measuring the straight line distance parallel to the valley walls between the vedah endpoints see Figure 2 1 Do not follow the meanders of the stream Be sure not to leap o over any hillsides when measuring the valley length Figure 2 2d 1 The valley length dashed i is shorter than the channel length solid If you are using paper maps use the scale at the bottom of the map to determine the valley length or read the length directly from your map wheel if it has the same scale as your map If necessary lengths meas ured in miles can be converted to feet by multiplying miles by 5 280 1 mile 5 280 feet If you are us ing computer mapping software to measure valley length and subsequent parameters utilize the soft ware s measuring tool and otherwise follow the same procedure for using a map wheel on a paper topog raphic map Evaluation with SGAT SGAT will generate the valley le
12. Upstream Lewis Creek Downstream Impact Rating by Stream Name can be used to graph the total impact scores for each reach along the longitudinal profile of the mainstem or tributaries This graphical organization of the data shows the upstream down stream position and proximity of reaches Total Impact with different impact levels which can inform management decisions For in stance if a highly impacted reach which may potentially be in adjustment 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 is located just upstream of a reach that DistoncaUps team niles has received a very low impact rating l you may be concerned about adopting a Figure 8 2 Example of downstream to upstream locations of im strategy to protect the low impact reach _ Pacted reaches Note To change or modify this report export the data to an Excel spreadsheet Phase Stream Geomorphic Assessment Vermont Agency of Natural Resources 69 April 2004 Steps 9 Provisional Geomorphic Condition Evaluation Overview Background The Provisional Geomorphic Condition Evaluation is comprised of three separate yet interrelated evaluations of the reaches in your watershed which are adjustment process reach condition and reach sensitivity These evaluations will prove to be valuable information at the watershed level The database tools described below help determine the geomorphic condition of reaches by exam
13. VT Tax Department Mapping Program Note that the Vermont Mapping Pro gram provides every town with a set of orthophotos for the town s geographic area and that these photos are usually available for use at town offices Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 38 April 2004 Local knowledge If you suspect rapid land use changes in your watershed consult land manag ers town officials and citizens who can inform you of recent land use changes Town tax maps can assist in tracking changes in residential and commercial development Evaluation with SGAT SGAT generates total surface area for each land cover land use LcLu type within each reach s sub watershed Step 4 1 and river corridor Step 4 2 Data Entry SGAT stores this data in dBase tables which can be exported into the LcLu database or opened in Excel for evaluation The LcLu database is separate but associated with the Phase 1 database and contains stan dard reports that show the percent area of each LcLu type within a reach s watershed Step 4 1 and river corridor Step 4 2 Users can review the data in these standard reports and choose the appropriate values to enter into the Phase 1 database The database reports automatically highlight in gray the dominant LcLu type for both the reach s sub watershed and river corridor Data Sheet 4 Land Cover Reach Hydrology 4 1 WATERSHED LAND COVER LAND USE SGAT Data
14. ad justment process for each reach in the report labeled Table 9 Condition Adjustment Process and Sen sitivity Initially the highest scoring adjustment process may be considered the current adjustment proc ess occurring in the reach Many reaches may have a high score for two or more adjustment processes Usually if a stream is undergoing one type of adjustment especially degradation or aggradation then it will be undergoing other forms of adjustment as well Use the concurrent adjustments column on Data Sheet 9 Appendix A to indicate the adjustment process with the next highest or equal score s Since channel adjustment processes are typically the result of the cumulative effect of different stressors a minimum cut off value of 4 has been established to recognize that while all reaches will likely have some impacts they may not necessarily be in adjustment Where there are multiple adjustment processes with the same or nearly the same score greater or equal to 4 chose multiple for the concurrent adjust ments column If none of the adjustment processes have a score greater than or equal to the cut off value it may indicate that the reach is in equilibrium not in adjustment and you may want to write None on the table for that reach Menu Degrading Downward erosion of stream bed via a head cutting process Aggrading Excessive sediment build up on streambed and bars Widening Erosion of
15. additional structures observed Channel and Bank Modifica Verify types locations and extent of channel modifications and 5 3 and 5 4 tions bank armoring 6 1 and 6 2 Corridor Encroachments Verify locations and extent of berms roads and development in Seiten Berms Roads and Development reach river corridor 6 3 Sediment Storage Verify type and relative size of sediment deposits record any addi tional sediment deposit features observed Phase 1 Stream Geomorphic Assessment April 2004 Vermont Agency of Natural Resources 63 Data Sheet 7 Bed And Bank Windshield Survey 7 1 DOMINANT BED FORM MATERIAL Background The type and distribution sorting of material found in the bed of the stream reflects the source and sup ply of sediments as well as the competency of the channel to transport the sediment a function of the channel depth and slope Measurements of the bed material and observation of bed form help character ize the stream s ability to carry different size material Bed form assessment is part of the Phase 1 windshield survey to give you an opportunity to provisionally describe stream types consistent with the Montgomery Buffington Stream Classification System 1997 Bed forms are examined in more detail in Phase 2 and Phase 3 field assessments when the entire stream reach is assessed Steeper reaches of a watershed generally have cobbles and boulders sorted into step pool bed forms This
16. and sub surface materials The River Corridor From Step 3 on you will be evaluating several parameters within the river corri dor which is described in detail in Appendix E Read Appendix E and delineate the river corridor for the reaches you will be assessing River corridor delineation can be done on screen to create a digital polygon data layer or it can be drawn on transparent overlays over paper copies of the orthophotos Be sure to mark reference points and reach numbers on the transparency so that you can line up the river corridor overlay with the correct reach when you use the overlay to measure other parameters later in the assessment Although both digital and paper map data sources and evaluation techniques are described below it is highly recommended that you secure the resources and expertise needed to undertake analysis of soils and geologic materials using GIS software and digital data layers The monetary investment is well worth the Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 28 April 2004 time saved in reviewing and piecing together soils information from several soils surveys and other geo logic maps Ideally soils analysis will be conducted using SGAT which automates delineation of the river corridor and the characterization and summation of soil properties within the river corridor for each reach see below Evaluation with SGAT SGAT will generate data for Step 3 3 Geologic Materials a
17. can then be assessed and the method of correcting or completing the information can be established A good first check to ensure data accuracy and completeness is to compare the original data sheets filled out by hand to those generated by the database Though tedious comparing each data entry line for line will ensure there are no errors resulting from simple typos and improper transfers of data from the raw data sheets to the database Many Phase 1 parameters are assessed in the field during Phase 2 and Phase 3 Stream Geomorphic As sessments If you have confirmed or changed remote sensing data in the Phase 1 database as a result of reach scale field assessments the quality assurance protocol includes using the field checked boxes in the database to indicate whether the parameter was confirmed by or changed as a result of windshield surveys or Phase 2 Phase 3 assessments It is very important that you do not characterize an entire reach in the Phase 1 database based on a field assessment of only a segment or part of the reach Wait until you have field assessed the entire reach before revising the Phase 1 database Revising the Phase 1 database with new and or field verified data may strengthen the use of the data in watershed analysis After you make these revisions it is essential to document the changes This should be done reach by reach parameter by parameter to ensure that you preserve the ability to cull out certain types of data
18. contour line crossing the stream nearest the reach endpoints If contour lines are far apart and a reach endpoint lies between interpolate the elevation based on the distance between the contour lines For example a reach endpoint located halfway between the 720 and 740 contour lines would be recorded as 730 For short reaches in gentle gradient valleys typically lt 2 it may not be possible to discern between downstream and upstream elevations Where this is the case do not guess Do not record elevations these reaches and check the Gentle Gradient check box on the datasheet and in the database Phase 3 field surveys involving an established elevation benchmark are required to accurately set upstream and downstream elevations for these gentle gradient stream reaches Use the check box in the database to in dicate when downstream and upstream reach elevations are determined with a survey during a Phase 3 assessment Evaluation with SGAT If you are using SGAT you can enter the elevation of each reach break in the data review screen in SGAT Step 10 Use the same method described above to determine reach break elevations SGAT uses the ele vations for successive reach breaks to determine the change in elevation between reach breaks in calculat ing valley and channel slopes Data Entry At the bottom of each column on Data Sheet 2 record the tool that was used to measure the parameter e g map wheel DeLorme mapping software
19. define the reference stream type designation More detailed information on the variables and descriptors used in field stream typing are provided in Appendix I and described further in the Phase 2 Handbook Step 2 14 and in the Phase 3 Handbook Step 6 Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources 25 April 2004 Table 2 2 Phase 1 Reference Stream Typing Chart ream Type Confinement Valley Dominant Bed Bed Form Valley Type Slope Material Step 7 Step 7 A Cascade Narrowly confined Very Steep Bedrock Tumbling jet and NC gt 6 5 Boulder wake flow A Step pool Confined Very Steep Boulder cobble Steps and channel NC 4 0 6 5 spanning pools B Step pool Confined or Semi Steep Boulder cobble Steps and channel confined NC SC 3 0 4 0 spanning pools B Plane bed Confined or Semi Mod Steep Cobble boulder Run riffle confined or Narrow 2 0 3 0 gravel or finer and rapid NC SC NW C or E Riffle Pool Unconfined Mod Gentle Gravel cobble Undulating or Dune ripple NW BD VB lt 2 0 sand or finer D Braided Unconfined Mod Gentle Gravel or finer Braided Channel NW BD VB lt 4 0 cobble boulder Use the Gentle Gradient descriptor rather than a calculated slope value for those reaches where eleva tions were not recorded in Step 2 1 In this table the D Braided channels may have the same valley confinement and slope characteristics as
20. elevations in Step 2 1 due to an indiscernible change in elevation along the reach use the Gentle Gradient check box on the data sheet and in the database to indicate valley slope Use the appropriate check boxes in the database to indicate whether the valley slope was determined during a Phase 2 or Phase 3 assessment 2 4 CHANNEL LENGTH SGAT Data Sources e USGS 1 24 000 topographic maps hard copy or digital Vermont Hydrography Data Set VHD 1 5 000 stream coverage if you don t have access to this coverage use the surface waters on the USGS 1 24 000 topographic maps Evaluation Read section 2 2 valley length to understand the difference between measuring valley length and chan nel length Use the measuring tool of a computer mapping software program or a map wheel to trace the blue line of the channel between the two reach endpoints If you are using paper maps use the scale at the bottom of the map to determine the channel length or read the length directly from your map wheel if it has the same scale as your map If necessary lengths measured in miles can be converted to feet by multiplying miles by 5 280 1 mile 5 280 feet Note If you are using a map wheel to measure your channel length it is likely that your channel length will be shorter than lengths measured with other tools such as computerized topographic mapping tools due to the difficulty in manipulating the map wheel through small tight curves in the c
21. from streambed to top of bank or slope Low lt 5 ft from streambed to top of bank or slope No Info Bank height is unknown Impact Rating for bank erosion H High High levels of bank erosion especially on medium to high banks L Low Low levels of bank erosion on low bank heights NS Not Significant No bank erosion evident No Info Impact of bank erosion is unknown Data Entry Use the check box in the database to indicate whether the extent of bank erosion bank height and the as sociated impacts for the reach have been confirmed or were based on Phase 2 or 3 assessments 7 3 DEBRIS ICE JAM POTENTIAL Background Debris jams are important to channel stability and aquatic habitat In general woody debris promotes stream equilibrium and high quality instream habitat On the other hand hazards from debris jams asso ciated with lateral erosion or channel avulsion may endanger infrastructure such as bridges that are too narrow as well as land uses or development occurring close to the channel Debris jams are a common cause of channel avulsions especially on alluvial fans Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 66 April 2004 Evaluation Look for places where an unconfined channel suddenly be comes constricted or where a relatively straight reach takes a dog leg or tight radius turn One example of a place with a high potential for debris or ice jamming would be where
22. in relation to other highly impacted streams throughout Vermont Reach conditions are defined using the following four categories Reference A reach with no significant channel or floodplain modifications and an adjacent forested ri parian buffer should score as a reference reach in a near natural condition Other reaches that have been modified or lack a buffer are evaluated on the extent to which their condition has departed from the reference condition of the same stream type Good Most streams in Vermont have experienced some degree of human induced change to their wa tershed floodplain and or channel Where a stream is undergoing only minor adjustments or has sub stantially adjusted to previous modifications and is returning to a dimension pattern and profile in re gime with watershed inputs it should be evaluated as a reach in good condition For instance streams that have undergone planform adjustments in response to watershed clear cutting or road building dec ades ago may be near a reference condition today e g entering Stage V of the channel evolution proc ess Appendix C A stream in good condition differs from a reference condition stream in that it is still undergoing adjustments due to current or historic modifications land cover changes or riparian buffer re establishment Streams in good condition may still be adjusting their belt width or building a flood plain but compared to the stream in fair condition they are withi
23. in various carbonate compounds dis solved in surface waters These compounds determine a stream s buffering capacity and pH levels the latter of which can directly influence an organism s health In general highly calcareous rocks those that contain a lot of calcium carbonate such as limestone foster streams with high buffering capacity that can maintain a fairly stable pH level within a range that supports aquatic biota Most igneous rocks such as granite do not contain abundant carbonate minerals and typically result in streams with low buffer ing capacity These streams have greater susceptibility to pH swings and low pH lev els that can be detrimental to aquatic biota Figure 3 5 shows a general distribution of calcareous and non calcareous bedrock types in Vermont Various studies have also shown that streams rich in cations espe cially calcium and magnesium which are often associated with bicarbonate are more productive biologically Allan 1995 sup porting more abundant and often more di verse aquatic communities Phase 1 Stream Geomorphic Assessment April 2004 Aggregated Bedrock Classes for Vermont Camonate rich rocks dolomite J limestone marble clastic sediments Calcareous clastic and metamorphosed clastic rocks approx 15 45 carbonate minerals Metasedimentary mocks primarily non calcareous Slate graywacke conglom erate Metasedimetary rocks primarily non cal
24. increasingly provide a more complete picture of how to assess reach conditions watershed wide and offer more powerful guidance in setting field assessment priorities Data Sheet 9 Geomorphic Condition 9 1 CHANNEL ADJUSTMENT PROCESS Background Detailed descriptions of channel evolution and channel adjustment processes are provided in Appendix C and Step 6 of the Phase 3 Handbook Phase 1 data can be used to set a hypothesis and provisionally as sign adjustment processes that may be occurring in the reaches in your watershed based on modifications of their channels floodplains and or watershed and riparian vegetation Notes on Channel Evolution Exceptions and Outliers The Phase 1 query attempts to factor in the sequence of ad justments that occur in one of the more common channel evolution process seen in Vermont It is important however to remember the sequential and temporal aspects of the channel evolution process Appendix C For instance channel deg radation may be followed by channel widening which is often followed by channel aggradation and plan form adjustment If your provisional Phase assessment shows channel degradation as the current process it may be reasonable to find in the field an incised widened channel that is currently aggrading In this example the Phase 1 may have correctly picked up on causal factors that should indicate channel degradation but perhaps due to interceding flood events the channe
25. is because the stream easily transports smaller materials downstream and scours larger materials over relatively shorter distances into lines called steps As you go further down in the watershed where slopes are more shallow the bed material generally becomes finer moving towards sands and gravels near the mouth of most large rivers in Vermont Evaluation Choose the bed form and dominant bed material size class which best describe the reach from the menus below Indicate No Info if you cannot see enough of the reach to make a determination Menu Bed Forms Description Generally occur in very steep channels narrowly confined by valley walls Characterized by tum Cascade bling jet and wake flow disorganized bed materials typically bedrock boulders and cobbles Small partial channel spanning pools spaced lt 1 channel width apart common Often associated with steep channels in confined valleys Characterized by longitudinal steps Step Pool formed by large particles boulder cobbles organized into discrete channel spanning accumula tions that separate pools which contain smaller sized materials Occur in low to high gradient and relatively straight channels and may be either unconfined or Plane Bed confined by valley walls Composed of sand to small boulder sized particles but dominated by gravel and cobble substrates in reference stream condition Channel lacks discrete bed features such as pools riffles and point bar
26. may justify a reach break If you are familiar with evaluating the characteristics of soils and surfi cial geologic materials you may want to consider using this type of information in determining reach breaks This data can be found on NRCS soil survey maps available through NRCS and surficial geo logic maps available through the Vermont Geological Survey To determine if there are any significant geologic changes within your watershed find the streams and rivers of interest on the soils and surficial geologic maps and note any major changes in the surficial materials characteristics particularly erodibil ity Consider these locations as possible reach breaks Be sure to read about geologic materials in Step 3 of this Handbook and Appendix F before finalizing your reach breaks Evaluating Tributary Influence The confluence of major tributaries is a place to consider making a reach break on the mainstem stream receiving the tributary Major tributaries are those that constitute 10 or more of the primary watershed area at their confluence with the mainstem river or stream Break the mainstem reach just above the confluence of the major tributary This same rule applies when breaking reaches on the tributaries themselves consider the influence of minor tributaries those that feed major tributaries If you have delineated the watersheds of major tributaries within the primary watershed this will help you identify where to make reach breaks
27. narrowly confined valleys resulting in sinuosities close to 1 Review sinuosity values to make sure they are greater than or equal to 1 especially if you are using SGAT to cal culate sinuosity values see below Use the check box in the database to indicate whether the sinuosity was determined during a Phase 2 or Phase 3 assessment 2 7 WATERSHED SIZE SGAT Data Sources USGS 1 24 000 topographic map Vermont Hydrography Data Set VHD 1 5 000 stream coverage if you don t have access to this coverage use surface waters on USGS 1 24 000 to pographic maps Background Watershed size or drainage area is defined as the area of a river basin measured in a hori zontal plane that is enclosed by a topographic divide such that direct surface runoff from precipitation normally would drain by gravity into the river basin The National Handbook of Recommended Methods for Water Data Acquisition USGS 1977 Watershed size is used for calculating reference channel width Step 2 8 which is in turn a factor in calculat ing confinement Step 2 9 meander width ratio Step 6 5 wavelength ratio Step 6 6 and in delineating river corridors and subse quently evaluating them for land use land cover and floodplain modification impacts Steps 4 and 5 a lt a m Reach sub watershed boundaries eA mm Primary watershed boundary i i SA b AN SSO SW OE Figure 2 2 Example of reach sub watersheds Evaluation The ea
28. on the mainstem stream based on tributary watershed size In the interest of practicality you may choose to discontinue using major tributaries that contribute 10 or more of watershed area at their confluence with the mainstem in the headwaters where typically the main stem becomes a steeper more confined channel of similar stream type throughout Often in headwater situations numerous tributaries of similar watershed size come together over a short distance to make up a main channel In these cases you may choose to consider all of these as minor tributaries and perhaps only break a reach on the mainstem upstream of a group of confluences of these tributaries rather than at each one 4 Reach Numbering Reach numbering is necessary to efficiently organize track and communicate reach related data The following objectives are also met by the reach numbering conventions described below 1 The ability to differentiate between all river reaches within the statewide geomorphic assessment data management system accomplished with the state geographic number 2 The ability to discern where a reach is located within its watershed and to be able to query for data upstream of a reach provided by the hydrologic number and 3 The ability to link stream geomorphic and physical habitat data with other water resource data that has been stored electronically in other State databases provided by including fields for those data bases record identif
29. or 3 assessments Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 49 April 2004 5 4 CHANNEL MODIFICATIONS Data Sources e 1 5 000 orthophotos paper or digital DEC Stream Alterations Engineers Natural Resource Conservation Service staff Background Channelization is the process of chang ing the natural path of a river through activities such as windrowing and straightening Channelization may increase the down stream hazard potential due to an in crease in water velocity and power from the increased channel slope loss of ac cess to the floodplain and disturbance of the channel bed armor larger sub strates that typically cover the upper layer of the channel bed When the VS y INS channel slope is increased the velocity Figure 5 3 Channel modifications identified on a topographic map increases This extra force may cause the river to degrade or cut down vertically into its bed Often the sediment that used to be in the bottom of the river of the now channelized area is re deposited downstream of the channelized area This results in aggradation or building up of the channel bed in this downstream area Aggradation in turn can re sult in channel widening bank instability and other channel responses most of which are detrimental to both riverside land and aquatic habitat MacBroom 1998 aie Y Pushing gravel to the stream margins without physically removing it from the
30. paper orthophotos or find the resources and or assistance to digitize the 1970 s orthopho tos for areas of specific interest in order to complete the same GIS based analysis that can be done for current LcLu using the digital 1990 s series orthophotos Menu Wetland Open Water lakes ponds reservoirs streams and wetlands Forest Coniferous and or deciduous forest Shrub Small trees shrubs and unmanaged grasses Field Agriculture pasture or hayfield orchards groves nurseries Crop Agriculture land tilled to grow crops Residential Developed land with rural roads and houses and land that is managed as lawn Commercial Developed land with retail businesses and larger state roads and Interstate highways Industrial Developed land with industry Impact Rating for Corridor Land Cover Land Use H High 10 or more of reach corridor is crop and or developed L Low Between 2 and 10 of reach corridor is crop and or developed NS Not Significant Less than 2 of reach corridor is crop and or developed Evaluation with SGAT SGAT will clip the current digital LcLu layer to the reach corridor and generate tables that can be re viewed in Excel or the LcLu database to determine the dominant and sub dominant LcLu types and their percent coverages within each reach s river corridor Be sure not to sum the data for the entire corridor area upstream of the reach break skip SGAT Step 1
31. recorded history of jams and flooding impacts Low Channel dimension pattern and profile suggest jams are possible but there is not a recorded history of flooding and erosion impacts Not Significant No noticeable sharp bends narrow stream crossings or wide NS shallow channel areas that may lead to ice and debris jamming no recorded his tory of jamming No Info Potential for debris or ice jam in reach is unknown H L Data Entry Use the check box in the database to indicate whether the type of debris or ice jam locations and their as sociated impacts for the reach have been confirmed or changed based on Phase 2 or 3 assessments Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 67 April 2004 Step 8 Stream and Watershed Impact Ratings Overview Background Since the Phase 1 Watershed Assessment is largely dependent on remote sensing data it is assumed that the channel and floodplain modifications identified elicit predictable responses by the various stream types due to assumed changes in channel slope and watershed inputs of sediment and water caused by these modifications An example would be the well documented response that certain riffle pool streams undergo following channelization and floodplain development The increased channel slope and stormwater runoff initiate major adjustment processes Such streams exhibit a high degree of vertical and lateral adjustm
32. sediment that they undergo major adjustment of chan nel dimension pattern and profile Riparian vegetation plays an important role in aquatic ecosystems by providing food and cover for stream dwelling organisms as well as habitat and travel and dispersal corri dors for terrestrial wildlife Evaluation Using orthophotos estimate the percent of each buffer width category along the right and left banks de termined facing downstream of the reach Record the dominant buffer width categories for the right and left banks of the reach using the choices in the menu It is likely that the reach you are evaluating has varying buffer widths along its length The dominant width is not the average width but rather the width category from the menu that occurs most often throughout the reach see example in Figure 4 1 If you are using GIS software you can overlay the VHD stream layer on the orthophotos and use the software s buffering tool to delineate the buffer width categories in order to help visualize the buffer condition Buffer Percent Width Category LB RB 0 25 60 60 26 50 10 0 51 100 0 30 gt 100 30 10 Dominant buffer width category shaded in gray Menu 0 to 25 feet 26 to 50 feet 51 to 100 feet gt 100 feet Fallow land historically cleared and or cultivated and now reverting back to a woody vegetation may be difficult to ag os interpret usin
33. statewide reach condition is also generated and listed along side the within watershed reach condition in a separate database report The Vermont River Management Program has queried Phase 1 assessments from around Vermont completed as of March 2004 and provisionally set the statewide high adjustment score value at 16 and uses this HS to generate a statewide reach condition using the computation process described above The Within Watershed and Statewide Reach Condition Comparison Report will allow you to compare the condition ratings of your reaches to each other as well as with those from other assessed reaches around Vermont Menu In Equilibrium no apparent or significant channel floodplain or land cover 0 85 1 0 Reference modifications channel geometry is likely to be in balance with the flow and sediment produced in its watershed In Equilibrium but may be in transition into or out of the range of natural vari 0 65 0 84 Good ability minor erosion or lateral adjustment but adequate floodplain function any adjustment from historic modifications nearly complete In Adjustment moderate loss of floodplain function or moderate to major plan 0 35 0 64 Fair form adjustments that could lead to channel avulsions In Adjustment and Stream Type Departure may have changed to a new stream 0 00 0 34 Poor type or central tendency of fluvial processes significant channel and floodplain
34. the Phase 1 Reach Summary Report from the Phase 1 database see Appendix B and review the Phase 1 data for each reach Note any data you feel is ques tionable and verify this data during the windshield survey Take the reach summary reports and topog raphic maps for each reach and the watershed with you to make notations or corrections to the data Table 7 1 lists the parameters which particularly benefit from field verification Standard map codes and symbols for field maps are included in Appendix A In addition to filling out Data Sheet 7 described below take photographs of notable features and typical reach conditions Keep a photo log so you can label your photos by reach number A standard photo log form is provided in Appendix A Table 7 1 Phase 1 parameters which particularly benefit from field verification Step Number Parameter Notes 2 10 Valley Type and Confinement Verify reach breaks as defined by valley form Grade Controls Verify locations of known grade controls record on map the types 3 2 ot and locations of any additional grade controls observed 4 3 Riparian Buffer Verify dominant riparian buffer width category for the reach 4 4 Groundwater Inputs Record locations of any observed small tributaries and groundwater inputs wetlands seeps springs not already noted 51 Flow Regulation Water Verify locations of known flow regulation and water withdrawal i Withdrawal structures record any
35. the highest adjustment process score reach T4 1 S1 Evaluation for planform adjustment in the set of reaches The The database report generated for Step 9 1 Ad database query would assign 10 as the HS value and justment Process and Condition Values calculates calculate condition scores For example reach M19 in condition scores based on the formula in the box Figure 9 1 would have a condition score of 10 6 below and provides provisional stream conditions 10 9 10 7 10 8 4 x 10 0 25 Poor for each reach based on the scores in menu above Figure 9 1 You may choose to use the database Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 72 April 2004 generated condition categories or if additional knowledge and observations warrant choose a more ap propriate category Indicate by selecting the appropriate check box whether the condition ratings se lected were based on knowledge other than the calculated scores including windshield surveys Phase 2 assessments or Phase 3 assessments If you are using the Phase 1 database query to generate within watershed condition ratings be aware that by using the highest score HS to run the query you are calibrating the results to fall within the pos sible range of scores assessed within your watershed This has the advantage of helping you target the reaches within your watershed that have the highest impacts A between watershed or
36. to be in adjustment Phase 2 assessments con firmed the reach to be in adjustment and showed that the degradation process resulted in the ad justment of the stream reach to an F stream type It also showed that the active adjustment process was no longer degradation but now aggradation In this case the Phase 1 database was revised for adjustment process and geomorphic condition but not for stream type because the ref erence stream type for M19 is still a C In this example Figure 9 2 the Phase 1 adjustment processes and condition ratings were based on a watershed level evaluation using a watershed HS see discussion below The comparisons of watershed specific Phase 1 results with Phase 2 results obtained using a state standard field protocol should only be used as a way to explore the relationship between known causes and ob served effects 9 3 REACH SENSITIVITY Background Step 7 of the Phase 2 Handbook and Step 6 of the Phase 3 Handbook have more detailed discussion and guides on the factors affecting stream reach sensitivity and may be useful reading prior to undertaking stream sensitivity evaluations Evaluation Evaluate the sensitivity of reaches in your watershed Stream sensitivity is perhaps the most difficult pa rameter to evaluate There are generalizations that are useful however and may be invaluable to setting stream management priorities Shallow sloped streams in unconfined alluvial valleys s
37. to erosion will limit a river s ability to migrate laterally over time Erodible material if in large enough quantities may also prevent a river from migrating laterally over time For example a river that migrates into a large hillslope of erod ible sand may erode the toe of the hillslope but as material from the toe is transported downstream it is replaced by sands that slide into the river from above Therefore the margins of non erodible materials and tall hillslopes are considered valley walls Valley width is the horizontal distance across the valley floor that is between and perpendicular to the valley side slopes valley walls The change from the relatively flat valley bottom to the side slope is marked by significant breaks in slope indicated by the tightening of contour lines as the valley side slopes become steeper Some low valley terraces depending on their soil or geologic make up may confine or effectively stop the lateral movement of a stream channel In such instances it is helpful to have knowl edge of soils and geologic parent material when determining valley walls and thus valley widths Soil and geology maps will provide some insight as to whether a stream has deposited material there before or whether the soils are erodible Evaluation Measure valley width from USGS topog raphic maps Figure 2 3 Along the reach measure several widths with a ruler map wheel or computer measuring tool and record the average
38. which automates delineation of the river corridor and the summation of LcLu types within the river corridor and sub watershed for each reach see below Data sources GIS coverages A statewide land cover land use GIS coverage is available from the Vermont Center for Geographic Information VCGI This coverage can be downloaded for free from VCGI s website at http www vcgi org You will need proficiency with GIS software to view this coverage Note that this coverage has a 25 m grid cell pixel size which is fairly coarse for evaluating land use land cover within river corridors particularly in small watersheds Also the data from which it was created was produced in the mid 1990 s possibly making the data obsolete for areas that have developed recently It is important that you field verify LcLu data particularly within the river corridor Many regional planning commissions and towns also have GIS cover ages available and can provide printed maps for a fee upon request When using a GIS coverage be sure to note when the data was created In some areas even data collected 10 years ago may be obsolete for determining current land cover e Aerial photos and orthophotos Photographs are available at most NRCS offices the Department of Environmental Conservation Water Quality Division and some regional planning commissions Your town office may also have aerial and orthophotos available Orthophotos are available for purchase from the
39. 10 Figure 1 4 Example of reach numbering system 13 Figure 2 1 Valley length versus channel length 18 Figure 2 2 Example of delineating reach sub watersheds 21 Figure 2 3 Example of valley width on a topographical map 23 Figure 3 1 Locations of potential alluvial fans on a topographical map 29 Figure 3 2 Alluvial fan indicated by topographic lines 30 Figure 3 3 Natural and structural grade controls 32 Figure 3 4 Example of NRCS soil survey 32 Figure 3 5 Aggregated Bedrock Classes for Vermont 37 Figure 4 1 Example of estimating the percentages of buffer widths 42 Figure 5 1 Perched culvert restricting fish movement and migration 47 Figure 5 2 Examples of Vermont hard armored stream banks 49 Figure 5 3 Channel modification as seen from a topographical map 50 Figure 6 1 Roads located within the river corridor 54 Figure 6 2 Developments within the river corridor 55 Figure 6 3 Mid channel and point bars viewed on an ortho photograph 57 Figure 6 4 A amp B Meander migration high and low impacts 58 amp 59 Figure 6 5 Belt width measurement example 6l Figure 6 6 Wavelength measurement example 62 Figure 6 7 Example of a reach with both regular and irregular meander 62 Figure 8 1 Example of database repot summarizing impacts by category 69 Figure 8 2 Downstream to upstream locations of impacted reaches 69 Figure 9 1 Example of database report of adjustment process scores 71 Figure 9 2 Comparison of Phase 1 and Phase 2 Stream Conditions 13 Figure 10 1 Example
40. 27 April 2004 Step 3 Basin Characteristics Geology and Soils Overview Background The stream types identified in Step 2 provide basic information on how streams function or work to transport the water and sediment produced in their watersheds This is critical to understanding the ad justment processes a stream may go through in response to the channel and floodplain modifications ex amined in Steps 5 and 6 Sediment supply as a factor in stream equilibrium is also related to the geology and soils of a stream s watershed The geologic materials underlying a watershed have a strong influence on stream processes These materials include both the solid ledge or bedrock and the unconsolidated sediments that overlie the bedrock A stream carries not only water but also sediment Geology deter mines the source material that the river is carrying the way that material is carried and the rate of chan nel adjustments Stream reaches that have beds and banks composed of surficial geologic materials such as gravel sand silt clay or mixes of these are far more erodible than any of the types of unweathered bedrock found in Vermont This leads to a fundamental distinction between the bedrock controlled reaches and those un derlain by surficial deposits Stream reaches that have bedrock controlled beds and banks are relatively static systems The planform of a stream flowing over bedrock is largely controlled by preexisting weak
41. 3 for this parameter This parameter is only for the corridor of the reach The SGAT table needed for this step is S14LC12 Data Entry Record on the Step 4 data sheet and in the Phase 1 database the dominant LcLu type for the reach river corridor and the percentage of the reach river corridor that the dominant type covers Use the check box in the database to indicate whether the current corridor LcLu type and or impact ratings for the reach were confirmed or changed based on windshield surveys or Phase 2 or Phase 3 assessments Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 41 April 2004 4 3 RIPARIAN BUFFER WIDTH Data Sources 1990 series 1 5000 orthophotos digital or hard copy Vermont Hydrography Data Set VHD 1 5 000 stream coverage Background The riparian buffer is the area of land directly adjacent to the channel along the channel s banks and floodplain which is covered with native woody vegetation and largely unmanaged i e allowed to grow naturally with no cutting or cultivation Riparian buffers protect and enhance water quality fish and wildlife habitats aesthetics and recreational values associated with streams and rivers The roots of grasses shrubs and trees are critical to the ability of stream bank soils to withstand the erosive power generated during high water events Streams without riparian vegetation often experience high rates of lateral erosion and may see such large increases in
42. 5 52 5 1 Flow Regulations and Water Withdrawals 5 2 Bridges and Culverts 5 3 Bank Armoring or Revetments 5 4 Channel Modifications 5 5 Dredging and Gravel Mining History Phase 1 Stream Geomorphic Assessment April 2004 VT Agency of Natural Resources Step 6 Planform Changes and Floodplain Modifications 53 62 6 1 Berms and Roads 6 2 River Corridor Development 6 3 Depositional Features 6 4 Meander Migration Channel Avulsion 6 5 Meander Width Ratio 6 6 Wavelength Ratio Step 7 Bed and Bank Windshield Survey 63 67 7 1 Dominant Bed Form Material 7 2 Bank Erosion Relative Magnitude 7 3 Debris and Ice Jam Potential Step 8 Stream Impact Ratings 68 69 8 1 Impact Rating 8 2 Priority Rating Step 9 Stream Geomorphic Condition Assessment 70 75 9 1 Channel Adjustment Process 9 2 Reach Condition 9 3 Reach Sensitivity Step 10 Like Reach Evaluation 76 Quality Assurance Protocol 71 80 Phase 1 References 81 82 Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources ii April 2004 Figures Figure Number Description Page Figure 1 1 Confined narrow and broad valley types 8 Figure 1 2 Reach break based on a change in the valley width 9 Figure 1 3 Reach break due to a change in valley slope and confinement
43. 6 1 Route 2 Interstate 89 and the railroad are all located ridor Also write None if there are no within the corridor of the Winooski River The meander bends roads or railroads and you have no in were likely cut off when the railroad was built formation about berms or improved paths If during windshield surveys or Phase 2 assessments you find berms new roads or improved paths the Phase 1 evaluation of this parameter should be modified Stream crossings where the road runs perpendicular to the stream are considered under Step 6 2 and are not a part of this parameter These structures are not necessarily a problem with respect to floodplain function unless berms and fill were used to elevate the road bridge or culvert Note berms on the water shed map with a B Retain a paper map or digital GIS shape file of berm and road encroachments for later use in quality assurance documentation field verification and for display purposes Menu RB berms roads railroads or improved paths located within river corridor on right bank only LB berms roads railroads or improved paths located within river corridor on left bank only RB amp LB_ berms roads railroads or improved paths located within river corridor on both banks None No evidence of berms roads railroads or improved paths in river corridor Base your impact rating on the percent of the reach length that has been encroached upon by berms roads railroa
44. 970 s should be compared with the series produced in the 1990 s Digitize on the computer or manually trace on mylar or paper k i mE overlays the historic and current Figure 6 4A Meander Migration and Avulsion High Impact T998 Location Ss RE ch Phase Stream Geomorphic Assessment Vermont Agency of Natural Resources 58 April 2004 channel locations Look for places where the two channel lines diverge to identify channel migration and or avulsions that have occurred during the time period covered by the photos See detailed instruc tions below Overlay method for evaluating channel migration Place the tracing paper or mylar on top of a historic orthophoto i e the 1970s orthophotos Mark a north arrow on the tracing paper write the name and date of the underlying orthophoto on the tracing paper Using a colored pencil mark reference points a silo a cross roads a V shaped intersection etc that also appear on the recent series of photos that you are us ing Using this same color pencil trace the course of the river Mark the active channel and all aban doned channels Next overlay the tracing paper or mylar on the recent orthophoto i e the 1990 s orthophotos for the same location If necessary adjust the scale of the recent orthophoto to match that of the historic photo with the aid of the computer or copy machine Line up the reference points on the tracing paper that you marked from the historic ph
45. Before starting your project the various constituents involved in the project should get together to be sure the goals of the project are understood It is also a good time to review the steps of the process and if there are multiple partners collecting data that each person understands their part in the project A Phase 1 Task Register table Appendix A can be used to assist in this process Protocol Steps Watershed characteristics evaluated as a part of this assessment protocol are referred to as parameters and have been organized under seven assessment steps For example a protocol for measuring water shed size is found in Step 2 7 the seventh parameter evaluated in Step 2 Data Sheets Paper data sheets Appendix A and the database data entry forms Appendix B are organized by step and parameter number and have a heading to record the following information gt Stream Name The name of the stream or river printed on the USGS topographic map For un named tributaries use the tributary numbering system outlined in Step 1 of these protocols gt Sub watershed It is also helpful to note the name of the receiving water in parentheses Sub watersheds are generally at the scale of 16 sq mls to 63 sq mls National Hydraulic Unit Code 10 Scale Watershed delineations showing the 8 and 10 Scale Hydraulic Units and their codes are available as GIS data layers from the Vermont Center for Geographic Information VCGI at www vc
46. HASE 1 INTRODUCTION This Handbook is a guide to the Phase 1 Watershed Assessment the first of 3 phases of the Vermont Stream Geomorphic Assessment protocols Phase 1 is carried out using existing data such as topographic maps orthophotos agencies and organizations databases local and resource specialists knowledge and windshield surveys Windshield surveys provide field data through quick observation without exten sive field measurements The data collected in a Phase 1 assessment provide an overview of the general physical characteristics of a watershed Maps aerial pictures and historic information will be invaluable when combined with field interpretations in piecing together the story of a stream s response to the natural and human disturbances that have occurred over time at the watershed scale Where to Complete a Phase 1 Watershed Assessment Where to complete a Phase 1 watershed assessment is largely a question of scale How much of the main stem should be assessed Which tributaries should be looked at With a good team of resource special ists financial support and time you may be able to complete an assessment for a 100 square mile water shed in 2 to 3 months It is highly recommended that you and your team review the parameters or char acteristics described in this handbook A limited assessment of stream reaches and tributaries will pro duce information you need to solve problems but only if y
47. River Corridor Management Geomorphic Assessment internet web page at www vtwaterquality org rivers htm Table of Contents Step Description Page Introduction 1 6 Where to Complete Phase 1 Assessments Final Products of the Phase 1 Rapid Stream Assessment Basic Methods and Skills Materials Needed Getting Started Phase 2 Quality Assurance Program Starting the Assessment Defining Stream Reaches 7 14 Delineating the primary watershed Selecting assessment streams Defining geomorphic reaches a visual first cut Reach Numbering Watershed Orientation verifying reach breaks in the field Step 1 Reach Locations 15 1 1 Reach Description 1 2 Town 1 3 Latitude and Longitude Step 2 Determining Stream Types 16 27 2 1 Downstream and Upstream Elevations 2 2 Valley Length 2 3 Valley Slope 2 4 Channel Length 2 5 Channel Slope 2 6 Sinuosity 2 7 Watershed Size 2 8 Channel Width 2 9 Valley Width 2 10 Confinement 2 11 Stream Type Step 3 Basin Characteristics Geology and Soils 28 37 3 1 Alluvial Fan 3 2 Grade Controls 3 3 Geologic Materials 3 4 Valley Side Slopes 3 5 Soil Properties Step 4 Land Cover and Reach Hydrology 38 44 4 1 Watershed Land Cover Land Use 4 2 Corridor Land Cover Land Use 4 3 Riparian Buffer Width 4 4 Groundwater and Small Tributary Inputs Step 5 Instream Channel Modifications 4
48. SGAT User Manual details how to process and export data from SGAT to the Phase 1 database Sending electronic copies of your data entered into the template database tables to the DEC River Man agement Program to include in the state geomorphic database provides the following benefits gt ensuring that a duplicate copy of the data exists in an alternate location gt building a statewide database that will result in a more powerful problem solving tool and gt receiving assistance from other geomorphic assessment professionals in data interpretation Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources 5 April 2004 Phase 1 Quality Assurance Program At the start of your Phase 1 assessment establish a QA team that includes the primary data collector s This team will be responsible for reviewing the data collected Members of this team need to be trained in the protocols and use of the Phase 1 database and at least one member of the team should be trained in quality assurance techniques Training can be obtained from the DEC River Management Program RMP or other trainers certified by the RMP Once data has been collected and entered into the database the standard reports and tables in the database can be generated and reviewed by the QA team The team can determine if there is information that is missing inconsistent with the protocols or needs further evaluation Data that raises concerns or prob lems
49. Sources Statewide land cover land use GIS coverage available from VCGI at http www vcgi org e USGS 1 24 000 topographic maps 1990 series 1 5000 orthophotos digital or hard copy 1970 series 1 5000 orthophotos Aerial Photographs Background Lakes wetlands and perennial vegetation play an important role in a watershed by storing water and trapping sediment which helps to reduce flood peaks and maintain summer base flows in rivers and streams Urban development and cropland typically increase the peak and change the duration of storm water and sediment runoff events Evaluation Use the data sources listed above to visually estimate the dominant current and historic land cover land use types for each reach s watershed The dominant cover type is the one that covers the most surface area within the reach watershed Make sure you are considering all the land area contained within the reach s watershed from the downstream end of the reach upstream to the outer primary watershed bound ary For current LcLu only record a subdominant LcLu type Also estimate and record the percentage of the reach watershed covered by urban and crop land use types Determine current LcLu using the most recent orthophotos available which are currently the 1990 s se ries orthophotos taken for all of Vermont You may need to supplement this data with local knowledge in areas where land use is changing rapidly For historic LcLu consult the 1970 s
50. Vermont Stream Geomorphic Assessment Phase 1 Handbook WATERSHED ASSESSMENT USING MAPS EXISTING DATA AND WINDSHIELD SURVEYS Vermont Agency of Natural Resources April 2004 Authorship and editing of the Phase 1 Stream Geomorphic Assessment Handbook and Database was the collaborative effort of Mike Kline DEC River Management Program Christa Alexander Vermont Department of Fish and Wildlife Staci Pomeroy DEC River Management Program George Springston Norwich University Dept of Geology Shayne Jaquith DEC River Management Program Barry Cahoon DEC River Management Program Larry Becker Vermont Geological Survey Funding for assessment protocol development has been provided by the U S Environmental Protection Agency U S Fish and Wildlife Service Conservation and Reinvestment Act Funding Federal Emergency Management Agency Lake Champlain Basin Program Vermont Agency of Transportation Research Grant Vermont Geological Survey State Map Grant Acknowledgements Other Agency of Natural Resources staff who worked on the Phase 1 Handbook include Shannon Hill of the River Management Program Jim Ryan Ethan Swift of the Water Quality Division Planning Section and Joe Zuccarello Department of Fish and Wildlife Special thanks to Brenda Clarkson of the DEC Information Technology Section for her help in database development An initial draft outline of the Phase 1 Handbook was provided through contracted services with Lori Barg o
51. a river has to make a tight turn under a bridge that is too narrow Over widened shallow streams with mid channel bars associ ated with channel slope transitions or changes in channel con finement are also places with high potential for debris or ice jamming A large channel spanning dead fall tree if sus pended above the bed but firmly lodged against channel banks or valley side slopes may also catch debris during high flow events Mark your map with the location of known debris or ice jams with the letters DJ DEC River Management Engineers road and highway fore man river resource professionals town officials and local residents may all be sources of information on where ice and debris jams have occurred historically Ice jam forming upstream of dam on the Menu Winooski River Vermont Bend Sharp angle gt 90 degree turn in channel planform Bridge Narrow or low clearance bridge and or multiple bridge piers Culvert Small diameter compared to stream width and or multiple culvert openings Shallow Wide shallow channel with mid channel bars Debris Observed jams of woody debris Multiple More than one type of potential cause for debris jam None No potential debris or ice jam No Info Unknown if there are debris or ice jams or their potential in reach Impact Rating for debris ice jam potential High Existing jams causing erosion and stream migration near infrastructure or
52. act Rating for Watershed Land Cover Land Use H High 10 or more of the reach watershed is crop and or urban L Low Between 2 and 10 of reach watershed is crop and or urban NS Not Significant Less than 2 of reach watershed is crop and or urban Evaluation with SGAT SGAT clips the current LcLu layer to the reach sub watersheds and generates a table named S14L W13 that sums the percent area of each LcLu type in the reach watershed This is done in Step 13 of SGAT This table can be exported to the LcLu database or opened in Excel to determine the dominant and sub dominant LcLu types and percent composition for each reach s watershed Data Entry Record on the Step 4 data sheet and in the Phase 1 database the dominant LcLu type for the reach water shed and the percentage of the reach watershed that the dominant type covers Use the check box in the database to indicate whether the current watershed LcLu type and or impact ratings for the reach were confirmed or changed based on windshield surveys or Phase 2 or Phase 3 assessments 4 2 CORRIDOR LAND COVER LAND USE SGAT Data Sources Statewide land cover land use GIS coverage available from VCGI at http www vcgi org e USGS 1 24 000 topographic maps 1990 series 1 5000 Orthophotographs digital or hard copy 1970 series 1 5000 Orthophotographs Aerial Photographs Background Land use land cover within the stream corridor is particularly import
53. act scores for all the reaches you evaluated in the watershed A database query also provides categorical impact scores which are sub total scores for each of the following catego ries Land Cover and Reach Hydrology Step 4 Channel Modifications Step 5 Floodplain Modifica tions and Planform Changes Step 6 and Bed and Bank Condition Step 7 Reaches which scored low impact ratings because you were unable to collect information for one or more parameters should be tracked using the Step 8 database report As complete information is gathered for a given parameter enter this data into the Phase 1 database and calculate the impact ratings for that parame ter and recalculate the total impact rating for the reach Be to update Phase 1 data and impact ratings with field verified information collected during windshield surveys and Phase 2 and Phase 3 assessments Menu 2 High H Strongly Evident Highly Significant 1 Low L Evident May Be Significant 0 Not Significant NS Not Evident Insignificant 0 No Info Not Rated Unknown No data collected Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 68 April 2004 8 2 PRIORITY RANKING Evaluation The database report Phase 1 Categorical Impacts by Watershed provides total and categorical impact scores for each reach and is sorted by confinement stream type and watershed size in that order to fa cilitate the ranking of di
54. aluation After completing all or parts of Steps 1 through 10 of the Phase 1 Stream Geomorphic Assessment Handbook you should complete the Quality Assurance Sheet in Appendix A and enter the information in the Phase 1 QA database Use the following protocols in completing the QA sheet QUALITY ASSURANCE WORKSHEET QA Team Leader The name of the local quality assurance team leader ANR Team Leader The ANR staff member serving on the quality assurance team who will conduct the State QA review Training Indicate the types of ANR sponsored training received by one or more members of your assessment team Phase 1 Training on the completion of a watershed orientation and Steps 1 10 SGAT Training on the use of the Stream Geomorphic Assessment Tool including the GIS extension and the SGAT handbook Quality Assurance QA Specialized training to complete quality assurance reviews Watershed Orientation Completed Indicate whether or not a watershed orientation was completed Reach Break Review Indicate whether a trained member of the assessment team reviewed the reach breaks that were made in Step 1 and verified in Steps 2 and 3 This review is conducted to ensure reach break consistency and is ideally done by the local or State QA team leader Exclusive Use of Protocols and Database The Vermont ANR Handbooks are one of many different geomorphic assessment protocols that have been published by agencies organizations and priv
55. am observe the smaller particles that are often entrained around larger substrates and be sure to consider these in your evaluation of dominant bed material Menu Bed Materials Millimeters Inches Relative Size Bedrock Ledge outcrop Boulder 256 4096 10 1 160 Basketball to Volkswagen Bug Cobble 64 256 2 5 10 1 Tennis ball to basketball Gravel 2 64 0 08 2 5 Pepper corn to tennis ball Sand 0 062 2 00 0 002 0 08 Silt size to pepper corn No Info Dominant bed material is unknown Data Entry Enter bed form and dominant bed material size class data into the Phase 1 database under Step 7 If the reach has been evaluated under Steps 4 5 and 6 as having very few impacts and appears to be in good to reference condition then enter the observed bed form and dominant bed material size class into the Phase 1 database under Step 2 10 Reference Stream Type as well Use the check box in the database to indicate whether the dominant bed material and or bed form were confirmed or changed based on Phase 2 or 3 assessments 7 2 BANK EROSION RELATIVE MAGNITUDE Background All stream banks erode to some degree Bank erosion is a natural ongoing process and it is unrealistic to think that bank erosion can be or should be totally eliminated While bank erosion is occurring naturally over time it is a process that may be accelerated or decelerated by human activities The concern is not that erosion occu
56. and to some extent underlying geology as described below Specifically you will be looking at stream confinement valley width compared to stream width valley slope geologic materials and tributary influence to determine distinct geomorphic stream reaches within the watershed Background On the broadest level streams are classified by the shapes of the valleys they flow in steep and confined moderately steep and narrow or gentle sloped and broad Figure 1 2 below shows the different valley types and indicates the changes in sediment regime characteristics source transfer and response and water discharge as drainage area increases In general these valley types have different physical characteristics As you travel from steeper to gentler sloped valley segments the bed material transitions from larger boulders and cobbles to finer sands and gravel The amount of sediment deposited in the channel increases as the slope of the channel decreases Typically steeper headwater streams flow in relatively straight channels through narrow valleys The streams are confined in the valleys As the water moves downstream valleys generally become wider and Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 7 April 2004 the slopes become gentler Streams begin to wind around more becoming more sinuous with gentle channel gradients and finer bed materials Source Transfer Response a Naa gt ANS 4 Oji
57. ant with respect to sediment deposi tion and erosion during annual flood events Wetlands ponds and perennial vegetation moderate storm water and sediment runoff while the impervious surfaces within urban areas and the exposed soils found in cropland have the potential to increase watershed inputs Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 40 April 2004 Evaluation Use the data sources listed above to visually estimate the dominant current and historic land cover land use types for each reach s river corridor as defined in Appendix E The dominant cover type is the one that covers the most surface area within the reach s river corridor For current LcLu only record a sub dominant LcLu type Also estimate and record the percentage of the corridor covered by urban and crop land use types Determine current LcLu using the most recent orthophotos available which are currently the 1990 s se ries orthophotos taken for all of Vermont You may need to supplement this data with local knowledge and or windshield survey observations in areas where land use is changing rapidly For historic LcLu consult orthophotos from the 1970s Town tax maps and local knowledge may also be helpful As de scribed under Step 4 1 you may decide to limit your assessment of historic river corridor LcLu to those river areas where you notice a significant change from the current LcLu Visually estimate dominant his toric LcLu from
58. assurance checks and 3 ena bling database queries to identify reaches where there is little or no riparian buffer For instance a two mile long reach may have a dominant buffer width category of 50 to 100 along both banks but still have a 2000 foot segment with less than 25 feet on the right bank The buffer width percentage data can be processed in either Excel or the Access database to back calculate linear feet of bank of a specific buffer width category in any given reach Being able to query the data for such reaches is useful for locating potential sites in need of buffer revegetation within a watershed context The example shown in Figure 4 1 above would have an impact rating of Low because 60 of both the right and left banks have buffers that are in the 0 25 feet width category Use the check box in the data base to indicate whether the buffer widths data and the associated impact rating for the reach were con firmed or changed based on windshield surveys or Phase 2 or 3 assessments 4 4 GROUNDWATER amp SMALL TRIBUTARY INPUTS Data Sources e USGS 1 24 000 topographic maps hard copy or digital Vermont Hydrography Data Set VHD 1 5 000 stream coverage if you don t have access to this coverage use surface waters on USGS 1 24 000 topographic maps National Wetlands Inventory NWI maps The NWI maps for Vermont are produced by the U S Fish and Wildlife Service and are devel oped from aerial photo interpretation an
59. astrophic channel avulsions due to floods debris jams undersized road crossings structures or because of past channelization practices Often the loss of woody riparian vegetation causes or exacerbates channel migration and increases avul sion occurrences on certain sensitive depositional stream types Orthophotos can be used to look for areas where the river has migrated bifurcated or avulsed By com paring orthophotos from different time periods reaches that have migrated bifurcated or avulsed exten sively can be distinguished from reaches that have stayed in the same location over the same period of time Figures 6 4A and 6 4B Substantial changes in channel location usually occur in the lower deposi tional zone of the watershed On large streams migration bifurcation and avulsions can be easily seen on the orthophotos Figure 6 4A but channel avulsions on small streams in the upper watershed cannot easily be determined from orthophotos even though they may occur in that area The presence of channel avulsions on small streams can only be confirmed through a field visit Evaluation To identify channel migration bi furcation and or avulsions on large and medium sized rivers and streams compare the path of the channel from similarly scaled ortho photos of different years You should use the most recent ortho photos series that span a period of approximately 20 years For in stance the orthophotos produced in the late 1
60. atabase with the measured value for those reaches where you are fairly certain that your Phase 2 data is representative of the reach s reference con dition You should not enter field measured channel width values into the Phase I database if they are from a segment or reach that is in adjustment especially those measured on over widened streams or streams undergoing planform adjustment Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources 225 April 2004 Evaluation with SGAT SGAT will calculate reference channel width using VT HGC equations and the generated watershed size of each reach SGAT will perform the calculation for all reaches Caution should be used in retaining widths for those reaches that are not of a similar stream type and setting to those used in generating the HGCs see discussion above The user may choose to delete or note those channel widths that may not be accurate Data Entry Use the check boxes in the database to indicate whether the reference channel width for the reach was determined during either a Phase 2 or Phase 3 assessment 2 9 VALLEY WIDTH SGAT Data Sources USGS 1 24 000 topographic map Background For purposes of Phase 1 assessment the valley may be described as that land area through which the river is free to move laterally over time A river can be prevented from moving laterally by geologic material of specific quality or quantity Material such as bedrock which is resistant
61. ate companies Indicate whether you used the ANR protocols exclusively and if not what other protocols were used If the protocols are sufficiently divergent from the ANR protocols data will not be entered into the State stream geomorphic database Tools Used to Collect Data Transcribe the information about the tools and materials used to complete a protocol step as was recorded at the bottom of the Step 1 through 7 data sheets Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources J April 2004 Confidence Level Using the following definitions circle the level that best describes the confidence that you and your assessment team have in the Phase 1 data collected for each step in the protocols Low to Moderate Unsure of protocols and or used minimal historic data sources 1 5000 stream coverages were not available little to no field verification Moderate Understood and followed Phase Protocols used at least one historic data resource for parameters where appropriate little of no field verification suspect some watershed channel or floodplain modification activities not known Moderate to High Understood and followed Phase 1 Protocols used many historic data resources for parameters where appropriate some field verification suspect some watershed channel or floodplain modification activities not known High Used many data resources historical activities in area well documented field verified al
62. both banks leading to an over widened streambed Planform Rapid and or irregular meander movement and pattern None No significant adjustment process indicated Multiple Multiple adjustments indicated Phase 1 Provisional Adjustment Scores et Ht vx o e s e rar me poe p p p e fe 34 _ m a m wa u e 7 e Poor a je e h b coa Figure 9 1 Example of a database query output of provisional adjustment process scores See Appendix B to learn how the query generates Phase 1 Provisional Adjustment Scores The current adjustment process is indicated above as dark shaded boxes Other adjustment processes are shown in boxes with diagonal shading M3 would be evaluated as None meaning no significant adjustment process is likely occurring as indicated by the lack of scores gt 4 in the Phase 1 Provisional Adjustment Score columns Reach M9 SC Tasi Nw m6 nw T2251 NW m3 nw M2 nw Tsasa VB Tma vB Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 71 April 2004 9 2 REACH CONDITION Background A Provisional Geomorphic Condition Evaluation process has been established in the Phase 1 protocols to use the provisional adjustment process ratings to derive a condition rating for each reach To support the prioritization of reaches in Step 10 derivation of geomorphic conditions are made relative to the most impacted reaches within your watershed as well as those
63. bout other assessments in your watershed as you need to coordinate your reach numbering assignments with prior assessments completed upstream or downstream from where you plan to work Hydrologic Number The hydrologic number is an alpha numeric identifier that describes where a reach is located within the watershed drainage network This number does not create unique reach identifiers for reaches from different watershed assessments This numbering system by indicating into which reach a tributary enters allows one to evaluate the upstream watershed inputs to a reach through database que ries that sort by reach number and it provides the needed information to locate a reach within the water shed The SGAT program facilitates the assignment of reach hydrologic numbers See the SGAT User Manual for details The following numbering conventions are used to assign reach hydrologic numbers Mf designates reaches on the mainstem which are numbered sequentially from downstream to upstream as M01 M02 MO3 etc Figure 1 4 M T designates major tributaries on the mainstem those that drain 10 or more of the water shed area at their point of confluence with the mainstem These major tributaries are numbered sequentially from downstream to upstream along the mainstem as T1 T2 T3 etc They are pre ceded by the M that designates the mainstem reach into which they flow Individual reaches on each tributary are designated with a period a
64. careous schist phyllite qneiss Metasandstone and other quatz bearing mcks primarily non calcareous m Metasandstone and other quartz bearing Mcks somewhat calcareous Metamomphosed mafic volcanic ana clastic metasedimentary rocks minor carbonate el Ultramafics serpentine rocks talcs qunites ad peridotites al Plutonic granitic mocks and their metamorphic equivalents Figure 3 5 This map shows the distribution of calcareous and non calcareous bedrock types in Vermont Lake water quality studies con ducted by the Vermont Department of Environmental Conservation have shown that bedrock type heavily influences lake buffering capacity with those lakes having the lowest alkalinities generally lt 25 mg l occur ring in areas dominated by non calcareous bedrock types Clarkson 1982 Though data is insufficient to compare stream alkalinity with bedrock type in Vermont it can be presumed that in general stream alkalinity levels follow a similar pattern Vermont Agency of Natural Resources 37 Step 4 Land Cover and Reach Hydrology Overview Background Step 4 evaluates how watershed land use riparian vegetative cover and other hydrologic features influ ence the quantity and rate of water and sediment run off that may occur in a reach after storm events Changes in runoff characteristics may explain observed changes in channel size and shape why the chan nel is adjusting or why the channel
65. ch as bank armoring or bank erosion As a means of ensuring quality data it is neces sary to document such features on a working map that can be submitted to the River Management Section for QA review Using EPA s Reach Indexing Tool RIT provides an efficient means for documenting and measuring features of interest Use of the RIT also results in a dbase that can be imported into the Phase 1 database thus eliminating the need to manually enter the data Instructions on acquiring and us ing the RIT are contained in Appendix P Using the Geomorphic Assessment Databases Vermont ANR has also developed a geomorphic database and a soils land use land cover database for entering Phase 1 information from data sheets These database programs utilize Microsoft Access soft ware and contain data entry forms embedded data queries and a suite of standard data report forms These databases are available on computer disk by contacting the DEC River Management Program Appendix B shows examples of the databases forms and queries used to complete Phase 1 products Remote Sensing Skills The following remote sensing skills will be needed to complete the Phase 1 Watershed Assessment are Reading topographic maps Interpreting aerial orthophotos Measuring distances and areas on topographic maps and aerial orthophotos Calculating some basic mathematical equations examples are provided in the text Reading soil and geologic surveys These skills are ea
66. completed The QA sheet can then be updated to indicate the change in data The portions of the QA sheet completed by the assessor will assist in incorporating the data into the State Geomorphic Database see Appendix P As the data is brought into the State database ANR staff will review the data and the QA process and QA sheet will be completed This ANR level QA process will be done each time data is updated or changed and resubmitted to ANR Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources April 2004 Starting the Phase 1 Assessment Defining Stream Reaches To start the Phase 1 assessment you must first do the following 1 Delineate the primary watershed 2 Select streams within the watershed to be assessed 3 Visually define a first cut of geomorphic reaches for the assessment streams using the ground rules and guidance provided in this section 4 Number reaches according to the numbering systems outlined in this section 5 Conduct a watershed orientation to verify reach delineations and calibrate your eye to how features on the maps and orthophotos which you will be using to complete the Phase 1 assessment appear on the ground 1 Delineating the Primary Watershed Detailed instructions on how to delineate watershed boundaries and how to read topographic maps are provided in Appendix D Determine the boundary of the watershed that encompasses the stream s you are interested in assessing This i
67. d Assessment Third Branch Stream Classification Durham NH Pielou E C 1998 Fresh Water The University of Chicago Press Chicago Rosgen D 1996 Applied Fluvial Morphology Wildland Hydrology Pagosa Springs CO Schumm S A 1969 River Metamorphosis Proceedings of the American Society of Civil Engineers Journal of the Hydraulics Division vol 95 255 273 Schumm S A 1977 The Fluvial System John Wiley and Sons New York Schumm S A 1984 The Fluvial System John Wiley and Sons New York Vermont Agency of Natural Resources A Classification of the Aquatic Communities of Vermont prepared by the Aquatic Classification Workgroup for The Nature Conservancy and the Vermont Biodiversity Project October 1998 Water Resources Board 1999 Vermont Water Quality Standards Montpelier VT Williams G P 1986 River Meanders and Channel Size Journal of Hydrology 88 147 164 Thorne C R D R Hey and M D Newson 1997 Applied Fluvial Geomorphology for River Engineering and Management John Wiley amp Sons Chichester UK Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 82 April 2004
68. d help fill in the data gaps over time Table 1 2 Parameters and map codes for use in watershed orientation surveys Step Map Parameter Notes Number Code REN Record valley toe locations on map and generally note valley widths relative 29 D er in Walley Typeand Consinement to channel widths Verify visual first cut reach breaks 3 1 Alluvial Fan AF Map locations of any observed alluvial fans 3 2 Grade Controls GC Map locations and types of any grade controls observed Familiarize self with how land use cover types appear on maps and orthopho 4 2 Corridor Land Use Land Cover ae Pore Familiarize self with how riparian vegetation appears on orthophotos Gen 4 3 Riparian Buffer erally note riparian buffer widths and vegetation types Trib Map locations of any observed small tributaries and groundwater ace Groundwater Iriputs SS inputs wetlands seeps springs not already visible on maps Flow Regulation Water Withdrawal Dam 51 Weir Map locations of any observed flow regulation and water with Snowmaking withdrawal Snow drawal structures Irrigation withdrawal Irrig 5 3 and 5 4 Channel and Banik E Familiarize self with how channel modifications and bank revet ADES Tree E oe ments appear on orthophotos Corridor Encroachments B B Familiarize self with how corridor encroachments appear on maps 6 1 and 6 2 oa RD and orthophotos Map locations of observed features that are not Development Resid
69. d limited field checking The Vermont maps are mostly based on 1 80 000 scale color infrared aerial photos taken in 1978 These maps show the gen eral locations of wetlands ponds lakes and streams and are available in digital format from the U S Fish and Wildlife Service National Wetlands Inventory homepage at http www nwi fws gov Paper copies of the maps can be obtained from the DEC Water Qual ity Division Vermont Significant Wetland Inventory VSWI maps The VSWI maps are regulatory wetland maps produced from the NWI maps by the Vermont Agency of Natural Resources A GIS data layer has been produced from these maps and is available from VCGI Note that the regulatory wetlands shown on the VSWI maps are a subset of all of the various wetland and deepwater habitats shown on the NWI maps For more infor mation contact the Vermont Wetlands Office at 802 241 3770 Local Knowledge Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources A3 April 2004 Background Groundwater plays an important role in maintaining healthy aquatic ecosystems When Vermont s streams and rivers are experiencing temperature extremes during both winter and late summer ground water inputs are essential in moderating water temperatures such that streams remain habitable and pro ductive for aquatic organisms Fish adapted to cold water habitats such as Brook Trout Salvelinus fon tinalis are particularly sensitive to water t
70. de controls point theme Step 5 1 Flow Modifications identify water withdrawal sites dams and other features that modify flow point theme Step 5 3 Bank Armoring locate areas of bank revetments line theme Step 5 4 Channel Modification document sections of channel that have been modified line theme Step 6 1 Berms and Roads identify roads berms and railroads within stream corridor line theme that are not documented on USGS 1 24 000 topographic maps existing digital road data layers or visible on the 1990 s series orthophotos Step 6 5 and Step 6 6 Meander Width and Length record how and which meanders were measured line theme Step 7 2 Bank Erosion identify areas of stream bank erosion line theme Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources April 2004 80 Phase 1 References Allan J David 1995 Stream Ecology Structure and function of running waters Chapman amp Hall New York N Y Bierman P A Lini P Zehfuss A Church T P Davis J Southon and L Baldwin 1997 Postglacial ponds and alluvial fans Recorders of Holocene landscape history GSA Today v 7 no 10 p 1 8 Center for Watershed Protection et al 1999 Impact Assessment of Instream Management Practices on Channel Morphology Prepared for Vermont Geological Survey 4 Center for Watershed Protection et al 1999 Watershed Hydrology Protection and Flood Mitigation Project Phase II Technical Analysis Stream G
71. ds or improved paths Rate the impact as high if the stream is flowing in a broad shaped valley where travel infrastructure singularly or in combination with other developments cuts the stream off from a significant portion of the river corridor such that the valley is now effectively a narrow valley type valley width less then 6 channel widths for 20 or more of the reach length Under this scenario there may be increased stream power due to the confinement of high flows that may initiate a channel incision process The loss of river corridor i e valley width and potential floodplain width may lead or have already led to a dramatic increase in bank erosion and channel aggradation as the stream creates a new floodplain at a lower elevation Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 54 April 2004 Impact Rating for berms roads railroads and improved paths H High berms roads railroads or improved paths are within river corridor along 20 or more of reach length L Low berms roads railroads or improved paths are within river corridor along 5 to 20 of the reach length Not Significant berms roads railroads or improved paths are within river corridor along NS less than 5 of reach length Data Entry Use the check box in the database to indicate whether the percent of reach paralleled by berms roads railroads or improved paths and the associated impact for the
72. e low runoff potential OR undrained slow infiltration rate with high runoff potential D Slow infiltration rate high runoff potential Not Rated Not rated or no hydrologic group assigned Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 35 April 2004 Flooding Flooding characteristics for soil types are listed in the Top 20 table under the frequency of flooding category Soils formed in floodplains are indicative of areas where historical channel migration has occurred Silts and sands are carried by floodwaters and deposited in the floodplain Over time these floodplain soils can build into deep rich deposits The presence of floodplain soils can be used to determine historic channel migration areas This information is listed under the description of each soil Menu Flooding Description None or Rare Soil texture not indicative of frequent flooding Occasional Soil texture indicative of occasional flooding Frequent Soil texture indicative of frequent flooding Not Rated Frequency of flooding not indicated for soil type Erodibility Determine the erodibility of soils and estimate the percentage of the reach that contains soil materials that are highly or potentially highly erodible One option for evaluating this parameter is to read the general description of each soil and use the erosion potential of the soil with no vegetation as the erodibility value as
73. e 2 or 3 assessments You may update valley width data in the Phase 1 database with field measurements collected in Phase 2 Remember that in the Phase 2 protocol the measurements of valley width and confinement take into consideration any modification of the valley by berms or elevated roads If you enter field measured valley widths into the Phase 1 database make sure they represent the width of the natural valley and not the valley as modified by human development and infrastructure 2 10 CONFINEMENT Ratio of Channel Width to Valley Width SGAT Data Sources e Valley Width from Step 2 9 e Channel Width from Step 2 8 Evaluation To calculate confinement divide the valley width measured in Step 2 9 by the channel width calculated in Step 2 8 Use Table 2 1 below to determine the confinement and record the appropriate valley type code Table 2 1 Confinement Ratios Valley Type Confinement Valley Width Channel Width Ratio 1 NC Narrowly Confined 1 and lt 2 1 SC Semi confined 2 and lt 4 2 NW Narrow 4 and lt 6 3 BD Broad 6 and lt 10 3 VB Very Broad 10 with abandoned terraces on one or both sides This ratio is only as accurate as the channel and valley widths used in the derivation You should con sider all Phase 1 confinement ratios and valley types to be provisional until you can go in the field meas ure the reference condition channel width and the natural valley width Where channel and val
74. e ground conditions exactly These measurements are broad characterizations for a large area of land You should expect your meas urements to be consistent however and to accomplish this you need to use the same tools and measuring techniques throughout the assessment For example if you measure valley length with a map wheel measure the valley length for every reach with the same map wheel You should use the same technique to measure a parameter for all reaches within an assessment phase For instance if you are using a ruler and paper maps to measure valley width do not switch to a computer measuring tool halfway through your watershed assessment This is very important with respect to data consistency and repeatability A space on the data sheets has been provided to document the measuring tools used Evaluation with SGAT The term SGAT appears in parentheses after each Step 2 parameter for which SGAT can be used to generate data SGAT will generate and perform calculations for the following 2 2 valley length 2 6 sinuosity 2 3 valley slope 2 7 channel width 2 4 channel length 2 8 valley width 2 5 channel slope 2 9 valley confinement Valley width length and confinement values are only generated for those reaches where you choose to delineate valley walls by creating a GIS polygon layer usually done along most mainstem rivers larger tributaries and in some cases smaller tributaries in wider valleys Read the discussion under Val
75. e_ 1 A oa 8 4 6_ 3__ 4__ Fa mo h e Ms fo is 3Fai mo ho e ew p 5a m 3 eer Ce Ee E mo ho fe ma p T Poor 19 3 ms j e ea ja j p m fe mo Figure 10 1 Example of database report Phase 1 Like reach sorted by stream type condition and watershed size In Figure 10 1 reaches M17 and M21 could be considered like reaches They have the same valley confinement and stream type as well as similar watershed sizes and stream condition Conducting field investigations on Reach M17 would likely tell you a lot about the characteristics of Reach M21 Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 76 April 2004 Phase 1 Quality Assurance Protocol Background Completing the Quality Assurance Protocol is critically important to the data documentation process which will allow your assessment team and local regional state and federal partners to ascertain the accuracy and completeness of your geomorphic assessment work High quality data which is complete and accurate may form the basis of meaningful natural resource and river management projects and is therefore one of the primary goal of any assessment program Often both time and budgetary constraints do not support the collection of high quality data throughout a watershed Documentation of any assessment deficiencies should not necessarily be viewed as failure but rather as the first step in identifying future assessment needs Ev
76. each breaks defined later in the assessment process i e during Phase 2 or Phase 3 there is a sub reach numbering and tracking system provided to allow for this later distinction of reaches without having to renumber and reassess Phase 1 reaches See the Phase 2 Handbook Introduction for guidance on numbering sub reaches Choose one person to review all the reaches visually defined in your watershed in order to ensure consistency between different assessors reach designations Start defining reaches from downstream to upstream on the mainstem first and then determine the reaches on the major tributaries again downstream to upstream When a large tributary enters the mainstem this defines a new reach on the mainstem just above the confluence of the tributary See discussion under tributary influence later in this section Consider creating reach breaks on the upstream and downstream ends of large alluvial fans see Step 3 1 on alluvial fans due to the sensitivity of these streams to both vertical and lateral adjust ment Consider creating reach breaks on the upstream and downstream ends of large impoundments that have changed the general shape and fluvial processes of the stream or river Impoundments that warrant their own reach are those that are substantially wider than the natural channel In addition the dams creating these impoundments are typically constructed on natural grade controls i e bedrock w
77. ection management or restoration projects An interim way to set priorities within your watershed is provided through the completion of a Stream Impact Rating The River Management Program has developed guidance for basin planners on reach prioritization that places a high priority on identifying reference condition reaches for protection and red flagging strategic sites where certain channel adjustments may be occurring that would cause significant landowner conflicts A Like Reach Evaluation that groups the reaches in your watershed assessment by similar valley and stream types and similar geomorphic condition or impact rating Step 10 Grouping streams by like reaches is useful in selecting a manageable number of reaches on which to conduct the Phase 2 and Phase 3 field assessments By collecting detailed information on reaches that represent the dif ferent reach types in your watershed you are better able to characterize the entire watershed without conducting extensive and time consuming field surveys on the entire watershed The information collected on the representative reaches can be used to understand the other like reaches in the wa tershed Watershed Maps including USGS maps where your assessment team has made field notations dur ing the watershed orientation and windshield surveys and computer generated GIS watershed maps depicting Phase 1 reaches and data the provisional geomorphic condition and the like reach evalua t
78. ed for each reach by evaluating reach valley slope and confinement in Step 2 and are further refined using bed form and channel substrate data col lected during the windshield survey Step 7 Assigning a reference stream type using remote sensing and windshield survey data should be considered provisional Field assessments Phase 2 and Phase 3 consider other channel characteristics to assign existing stream types such as the degree to which the channel can access its floodplain Where field assessments indicate the absence of major human related stressors and little or no channel adjustment the field data used to type the reference condition can be used to refine the reference stream type assigned in the Phase 1 assessment and to update the Phase 1 database The Phase 1 database is reserved for reference stream type data in order to maintain a consis tent data layer for reaches throughout the watershed even though some evaluations may be more provi sional than others This reserves the data necessary to contrast reference stream types with the existing stream types determined in Phases 2 and Phase 3 Evaluation Using Table 2 2 below determine the stream type for each reach based on the confinement and valley slope Record the letter text description of the stream type on the data sheet During windshield surveys Step 7 you may have an opportunity to verify valley confinement dominant bed materials and bed forms and thus further
79. eeping these streams cold and well oxygenated are their nar row steep valleys which are typically still forested since these valleys are often unsuitable for other land uses The narrow valley helps shade the stream and the forest cover slows runoff shades the ground surface and enhances groundwater recharge all of which contribute to cold water temperatures in the stream In addition steep confined valleys result in stream bed forms that are more turbulent cascades and steps which along with cold water temperatures result in well oxygenated water In contrast the Northern Spring salamander is not likely to be found in low gradient large rivers that are typically warmer and support other organisms such as fish which compete with and prey on these salamanders Similarly a species which is adapted to warm water temperatures and is not a strong swimmer such as a Pumpkinseed Lepomis gibbosus will not likely be found in an A or B type streams which are typically cold water systems with faster flows The pumpkinseed is common however in low gradient slow mov ing streams and rivers which are usually C and E stream types Due to their broad low gradient valleys mix of land cover types and generally larger watershed sizes C and E type streams are usually warmer slower moving and possibly less well oxygenated than headwater A type streams and most B type streams Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources
80. emperature and will often move to areas of a stream that are fed by groundwater upwellings springs or seeps to overwinter or seek refuge during the hot summer months In addition to moderating water temperatures ground water is essential in maintaining stream flows and thus available habitat during late summer and during drought years when most of the base flow in streams is provided by groundwater Evaluation Using the VHD 1 5000 stream coverage wetland maps see below and local knowledge estimate the abundance of groundwater inputs that flow directly to the channel from adjacent wetlands small tributar ies springs and seeps If you do not have access to a 1 5 000 stream coverage use the 1 24 000 USGS topographic maps Although small tributaries may not be shown as blue lines on topographic maps they are usually present in areas where contour lines form tight upside down V s see Appendix D about read ing topographic maps Menu Abundant Frequent wetlands seeps springs or small tributaries adjacent to channel Minimal Occasional wetlands seeps springs or small tributaries adjacent to channel None No wetlands seeps springs or small tributaries adjacent to channel Unknown Data not available to determine presence or absence of adjacent waters Data Entry Use the check box in the database to indicate whether ground water and small tributary inputs for the reach were confirmed or changed based on winds
81. ent and at times may become high erosion hazard areas threatening channel equilibrium in both upstream and downstream reaches and possibly containing little or no habitat value The Step 8 Impact Rating and Priority Ranking process involves adding up the impact scores for the vari ous Phase parameters and using this total impact rating as a red flagging tool top identify reaches that may be in adjustment and outside the range of natural variability Data Sheet 8 Stream And Watershed Impact Rating 8 1 TOTAL IMPACT SCORE Evaluation Once each parameter in Steps 4 5 6 and 7 have been assigned an impact rating of High Low or Not Significant these ratings are translated into a total impact score To do this the impact ratings are as signed numeric values of 2 1 and 0 for High Low and Not Significant respectively To calculate the impact rating for each reach assign the appropriate values to the impact ratings from Data Sheets 4 through 7 and record these values on Data Sheet 8 For those parameters where you did not have ade quate information to rate impacts and you selected the No Info choice on the impact rating menu use a 0 impact rating value on Data Sheet 8 Next add all the impact rating values across a row to determine a total impact scores for each reach This step is done automatically for you in the database The database report titled Total Impacts by Reach summarizes the range of imp
82. eomorphic Assessment Prepared for Vermont Geological Survey 5 Center for Watershed Protection 2000 Memo No 6 Results of Biomonitoring Watershed Imperviousness Assessment Prepared for Vermont Geological Survey 6 Clarkson Brenda 1982 Vermont Acid Precipitation Program Winter Lake Surveys 1980 1982 Vermont Department of Water Resources and Environmental Engineering Montpelier VT 7 Dunne T and L Leopold 1978 Water in Environmental Planning W H Freeman and Co 8 Federal Interagency Stream Restoration Working Group 1998 Stream Corridor Restoration Manual Principles Processes and Practices 9 Fischenich C and H Allen 2000 Stream Management US Army Corps of Engineers Environmental Laboratory Water Operations Technical Support Program 10 Fischenich C 2000 Glossary of Stream Restoration Terms USACE Research and Development Center Environmental Laboratory Vicksburg MS 11 Henderson J E and D Shields 1984 Environmental Features for Streambank Protection Projects Tech Rpt E 81 11 U S Army Corps of Engr Waterways Experiment Station Vicksburg Miss 12 Hornbeck J W M Adams et al 1993 Long term Impacts of Forest Treatments on Water Yield A summary for Northeastern USA Journal of Hydrology V150 p 323 344 13 Jenkins Gerry and Peter Zika 1985 Waterfalls Cascades and Gorges of Vermont Vermont Agency of Environmental Conservation now Vermont Agency of Natural Resources 14 Jennin
83. erts in particular present migration bar riers to many fish species when constructed too steep or too long such that flow velocities in the culvert may be too great for fish to swim through Undersized culverts also become barriers when the outlet becomes perched above the channel bed due to the lack of sediment movement through the struc ture and the resulting channel bed degradation that occurs downstream Figure 5 1 The In general bridges usually are less likely than culverts to im pede fish and wildlife movements Culverts in stalled large enough and at grade with the channel bed such that natural stream bottom conditions are maintained within the culvert are less likely to be come migration barriers to aquatic species move Figure 5 1 Perched culverts often restrict the move ment ment and migration of fish and other stream dwelling organisms Evaluation Record the number of bridges or instream culverts within the reach by counting the number of times the reach is crossed by roads and driveways as shown on topographic maps and or orthophotos Identify other bridges and culverts especially those on driveways or recently constructed roads that do not appear on the maps and orthophotos during your windshield survey Bridges and culverts are likely to be lo cated near reach breaks as reach breaks often coincide with bedrock outcrops or a narrowing of the val ley which are also good locations for building stream crossin
84. es as headcuts in the streambed move up valley Kondolf 2001 Evaluation Using information and records from the DEC Stream Alteration Engineers determine if dredging or gravel mining has occurred in the reach and if so determine the relative frequency and volume of gravel extraction Some of this information may also be available from local excavators and road commission ers Record the dominant type of gravel removal which occurred in the reach using the menu below For instance if landowner gravel mining is occurring today where the reach was historically used for com mercial mining you would choose commercial mining as the dominant type because of the relatively high frequency and volume of gravel removal Dredging for flood conveyance may be intermediary be tween landowner gravel removal and commercial mining with respect to frequency and volume Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 51 April 2004 Menu Gravel Mining Recent or historic landowner removal of gravel from channel for personal use Dredgin Recent or historic removal of bed materials to increase channel cross section for ging flood conveyance or navigation purposes Commercial oe Mining Historic pre 1988 large scale commercial extraction of gravel from channel None No known dredging or gravel mining No Info Unknown if there was dredging or gravel mining Impact Rating for dredging and gravel minin
85. ey and the NRCS Top 20 table to determine the characteristic of each of the four soil properties listed for each soil type in the river corridor of the reach Then for each of the four soil properties add up the area covered by soil types with the same characteristic for a given soil property to determine which Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 34 April 2004 characteristic covers the most area within the river corridor For each soil property estimate the percent of the river corridor area in each reach covered by soils with the dominant characteristic Be sure to exclude area covered by water the stream or river from the total area of the river corridor Note that SGAT automates the summing of soil property characteristics for each soil property in each reach which greatly facilitates this step see Evaluating with SGAT below For the four soil properties listed below select the menu choice that characterizes the soils in the majority of the reach s river corridor and record this description on the datasheet and in the Phase 1 database Hydrologic Group Hydrologic groups for soil types are listed in the NRCS Top 20 table and are grouped according to their runoff characteristics Some soils are assigned to two hydrologic groups Dual grouping is used for one of two reasons 1 Some soils have a seasonal high water table but can be drained In this instance the first letter applies to the dra
86. f Step by Step Consulting Pilot projects which greatly enhanced the development of the Phase 1 Handbook were made possible by Michele Boomhower of the Lamoille County Regional Commission Marty Illick and Kristen Underwood and many volunteers of the Lewis Creek Association Amy Sheldon and Dan McKinley and many volunteers of the White River Partnership Shelly Stiles and Dick Schesinger and many volunteers of the Bennington area and Jed Wright of the USFWS Gulf of Maine Coastal program Cove Creek pilot project Central Maine Request for technical assistance training questions and comments should be directed to Mike Kline Fluvial Geomorphologist Christa Alexander Aquatic Habitat Biologist River Management Program Fisheries Division DEC Water Quality Division Department of Fish and Wildlife 103 South Main St Building 10 North 103 South Main St Building 10 South Waterbury Vermont 05671 0408 Waterbury VT 05671 0501 802 241 3774 802 241 1356 mikek anr state vt us christa fwd anr state vt us Larry Becker State Geologist Barry Cahoon P E Chief River Mgt Engineer Vermont Geological Survey River Management Program Laundry Building DEC Water Quality Division 103 South Main Street 1229 Portland Street Suite 201 Waterbury VT 05671 0407 St Johnsbury VT 05819 2099 802 241 3496 802 751 0129 larryb anr state vt us Barry Cahoon anrmail anr state vt us The Phase 1 Handbook and Database may be downloaded from the
87. fferent stream management priorities within your watershed For instance refer ence reaches indicated by low impact ratings may be identified to aid in the evaluation of impacted reaches having similar stream and valley settings When establishing the priority ranking of the reaches within a watershed be sure to track those reaches that received low total impact ratings due to one or more parameters being rated as No Info For in stance there may be reaches for which no information was initially available to complete an impact rating for bank erosion flow modification bank armoring and dredging history If further assessment revealed that each of these parameters would be rated as a high impact the total impact would be significantly higher and potentially result in a much higher priority ranking for the reach There are many different ways to prioritize your reaches based on your goals and objectives for the wa tershed There is a place on the data sheet for you to make notes on what criteria you used to prioritize your reaches for further assessment The priority ranking is not entered into the database because the ranking may change from season to season or as your assessment goals and objectives IReach Confine atershed Total i Number ment Size Impact Modification Modification 2 3 0 a E C C S S m9 Ne eT E nw e fso Figure 8 1 Example s m report ae ae by saan The database report titled
88. g H High Used historically for commercial gravel mining dredged for flood remediation L Low Used occasionally for annual 50 cubic yards of gravel extraction by landowner NS Not Significant No gravel mining or post flood dredging operations No Info Unknown if there was dredging or gravel mining Data Entry Use the check box in the database to indicate whether the type of dredging and gravel mining and its as sociated impacts for the reach have been confirmed or changed based on windshield surveys or Phase 2 or 3 assessments Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 52 April 2004 Step 6 Floodplain Modifications and Planform Changes Overview Background These protocols examine changes to lands adjacent to rivers and streams that may affect the vertical and lateral containment of flood flows River corridors first delineated in Step 3 are used to examine those lands that may be important primarily to the lateral or horizontal movement of flows Infrastructure and other developments that restrict the lateral movement of flood flows however also directly or indirectly through channel adjustment restrict the vertical access of a channel to its floodplain Though we often associate floodplains with large rivers over time even streams in semi confined valleys will have created a certain amount of floodplain In addition to providing floodwater storage and at
89. g orthophotos If during Figure 4 1 Example of estimating the percentages of buffer width windshield surveys or Phase 2 categories along a stream reach and the dominant width category along the right and left banks The stream is represented in blue on the photo The white line is located 100 out from the stream and can assessments you encounter fallow fields reverting to woody vegetation along a stream reach but assessed here as having be used to visually estimate buffer width categories along the reach Reach endpoints are indicated with solid black lines Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 42 April 2004 no buffer you should revise the Phase 1 database Agricultural and lawn or other highly managed household vegetation is not considered part of the riparian buffer Impact Rating for Riparian Buffer Width H High Over 75 of reach has little or no buffer 0 25 ft on one or both banks L Low 25 to 75 of reach has little or no buffer 0 25 ft on one or both banks NS Not Significant Less than 25 of reach has little or no buffer 0 25 ft on one or both banks Data Entry In addition to the Step 4 data sheet and additional buffer worksheet is provided to record the percent es timates for each buffer width category in the reach Recording this level of detail is important in 1 cal culating buffer width impact ratings for reaches 2 supporting data quality
90. g structures Make sure not to double count bridges and culverts from one reach to the next Calculate and record the percent of the reach length that is impacted by stream crossing structures as described in the menu below Be sure to include areas of the reach that are being influenced by bridges and culverts in adjacent reaches Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 47 April 2004 Impact Rating for bridges and culverts High gt 20 of reach length is channelized has split flow or makes a sharp S bend up stream or downstream of bridges or culverts L Low lt 20 of reach length is affected by bridges or culverts as described in menu above NS Not oo no apparent impacts from bridges or culverts on stream dimension pattern or profile H Data Entry Use the check box in the database to indicate whether the number of bridges and culverts and their associ ated impacts for the reach have been confirmed by or were changed based on windshield surveys or ANR Bridge and Culvert assessments If you change Phase 1 data based on ANR Bridge and Culvert Assess ment data check the Phase 2 check box in the database 5 3 BANK ARMORING or REVETMENTS Data Sources e 1 5 000 orthophotos paper or digital DEC Stream Alterations Engineers Natural Resource Conservation Service staff streambank condition surveys Regional Planning Commissions streambank conditio
91. generally in the range of 5 to 8 times the width of the channel Leopold 1994 and Williams 1986 Lower values may in dicate that the stream has become straighter and steeper possibly degrading its bed and losing access to its floodplain Higher values may indicate that the stream possibly due to an increase in fine sediment has started to aggrade and become more sinuous decreasing its channel slope as it migrates laterally Evaluation This parameter is only evaluated for those reaches you typed in Step 2 10 as C or E riffle pool or ripple dune reference stream types in narrow NW and unconfined BD and VB valleys For these reaches calculate the meander width ratio MWR by dividing the belt width B by the bankfull channel width Wort determined in Step 2 8 For reaches that have been straightened for more than half 50 of the reach length do not measure belt width but rather enter the channel width under the belt width column on the data sheet This will result in a meander width ratio value of one 1 for the reach which is rated as high impact For naturally confined and braided stream types enter a zero 0 on the data sheet in the MWR column for the reach and choose not applicable N A for the impact rating Determining Belt Width Use orthophotos in conjunction with topographic maps to determine the reach s average belt width Topographic maps help you discern the valley direction and recent orthopho
92. gi org gt Watershed The name of the main river or lake at the downstream endpoint of your watershed Watersheds are generally at a scale greater than 63 mi Hydraulic Unit Code 8 Scale gt U S G S Map Name USGS map name s on which the watershed is located Map names are usually located in the bottom right hand corner of the maps gt Observers Name of observer s completing the assessment gt Organization Agency Three or more letter acronym s of the organizations and agencies repre sented in the assessment crew Paper Records You are encouraged to use both the hard paper copy data sheets and computer report forms to catalogue and store assessment data Ideally data sheets are accompanied with paper maps These base maps will likely be USGS topographic maps but if you are using GIS you can create your own base maps that con tain topography and other useful data layers you may have available Be sure to include basic information on the map such as the watershed boundary the beginnings and ends of each stream reach and any wa tershed orientation and windshield survey field notes Step 7 gives a description of the map notation used in windshield surveys Computer Tools amp Outputs Use the template databases described earlier to store and manage your assessment data Appendix B of fers guidance on how to use the Phase 1 databases and provides examples of these forms and data queries used to complete Phase 1 products The
93. gs K L P R Bierman and J Southon 2003 Timing and style of deposition on humid temperate fans Vermont United States Geological Society of America Bulletin v 115 p 182 199 15 Johnson A W and J M Stypula Eds 1993 Guidelines for Bank Stabilization Projects in the Riverine Environments of King County King County Department of Public Works Surface Water Management Division Seattle Wash Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 81 April 2004 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Kondolf G M M Smeltzer and L Kimball 2001 Freshwater Gravel Mining and Dredging Issues Prepared for the State of Washington Center for Environmental Design Research University of California Berkeley CA Lane E W 1955 The Importance of Fluvial Morphology in Hydraulic Engineering Proceedings of the American Society of Civil Engineers Journal of the Hydraulics Division vol 81 paper no 745 Leopold L B 1994 A View of the River Harvard University Press Cambridge MA MacBroom J G 1998 The River Book Connecticut Department of Environmental Conservation DEP Natural Resource Center Technical Publications Program Hartford CT Montgomery D and J Buffington 1997 Channel reach Morphology in Mountain Drainage Basins Geological Society of America Bulletin v 109 no 5 pp 596 611 NRCS 2001 White River Watershe
94. h Terrain Navigator and Delorme Topo USA provide latitude and longitude as degrees minutes seconds For example Longi tude 44 17 00 N and Latitude 73 17 30 W If you plan to access the data in the future using Arc View or other GIS mapping software it is important to use 1983 datum and to use decimal degrees It is possible to convert degrees minutes seconds into decimal degrees by dividing the minutes and the sec onds each by 60 and then adding these to the degrees degrees minutes 60 seconds 60 GIS data sets from VCGI and the ANR are generally in NAD 83 State Plane Coordinates in meters Evaluation with SGAT SGAT will automatically generate the latitude and longitude and the NAD 83 State Plane Coordinates for each reach break Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources 15 April 2004 Step 2 Reference Stream Types Overview Background Reference stream types are designated to describe stream channel forms and processes that would exist in the absence of human related changes to the channel floodplain and or watershed Given the long his tory of stream channelization and human related changes to the Vermont landscape reference stream types are based largely on characteristics of the valley geology and climate of the reach Evaluation In Step 2 you will measure stream characteristics including valley slope and confinement to start the process of designat
95. han half of the reach Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 61 April 2004 length do not measure the wavelength but rather enter the channel width in the wavelength column on the data sheet This will result in a wavelength ratio value of one 1 for the reach which is rated as high impact For naturally confined and braided stream types enter a zero 0 on the data sheet for the reach and choose not applicable N A for the impact rating Determining Wavelength Meander wavelength is Wavelength measured as the distance in feet between two lines drawn perpendicular with the fall line of the valley one drawn at the beginning and one at the end of the meander wavelength Figure 6 6 The beginning and end points of the meander wavelength are located at thalweg inflection points or cross over points Alter eros over Bendway apex natively the beginning and end points may be set at the apex of bendway curves A meander wavelength Figure 6 6 Meander wavelength measured from consists of two bendways Use orthophotos in con cross over to cross over junction with topographic maps to determine the reach s average meander wavelength Topog raphic maps help you discern the valley direc tion and recent orthophotos offer the most accurate location of channel meanders and thalweg inflection points Measure at least three wavelengths in the reach to determine the average wave
96. hannel In general it is easier to obtain accuracy using map wheels on large rivers versus small streams and on straight channels versus highly sinuous ones Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources 19 April 2004 Evaluation with SGAT SGAT will calculate channel length along the digital stream layer based on the reach break locations Data Entry If you use the USGS 1 24 000 scale paper maps to measure channel length make sure to note their use at the bottom of the data sheet Use the check box in the database to indicate whether the channel length was determined during a Phase 2 or Phase 3 survey assessment 2 5 CHANNEL SLOPE SGAT Data Sources USGS 1 24 000 topographic maps hard copy or digital Evaluation Using the reach endpoint elevations recorded in Step 2 1 subtract the reach s downstream elevation from its upstream elevation to get the change in elevation for the reach Next divide the change in elevation by the reach channel length recorded in Step 2 4 to calculate the channel slope Multiply the channel slope by 100 to get percent slope See example below Example Calculating Channel Slope 1140 ft upstream elevation 1000 ft downstream elevation 140 ft change in elevation difference in elevation ft 140 0 023x 100 2 3 channel slope length of channel ft 6 000 Evaluation with SGAT SGAT will calculate reach channel slope based on the reach break elevations e
97. hic Assessment Vermont Agency of Natural Resources 50 April 2004 Menu Windrowing Pushing gravel up from the stream bed onto the top of either bank Straightening Dredging windrowing and bulldozing the stream into a straight course Multiple channel modifications where neither windrowing nor straighten Multiple ace ing are the dominant channelization type None No known channel modifications No Info Unknown if there are any channel modifications Impact Rating for channel modification H High Greater than 20 or reach has been channelized L Low Less than 20 channelized NS Not Significant No channelization observed No Info Unknown if there are any channel modification Data Entry Use the check box in the database to indicate whether the type s and extent of channel modification and its associated impacts for the reach have been confirmed or changed based on windshield surveys or Phase 2 or 3 assessments 5 5 DREDGING AND GRAVEL MINING HISTORY Data Sources DEC Stream Alterations Engineers Dredging NRCS Flood Damage Emergency Watershed Protection EWP Reports Background Dredging and mining gravel bars from a channel may initiate a channel evolution process see Appendix C Such activities straighten and steepen the channel and cause the river to cut down and erode its bed The stream channel eventually aggrades with sediments supplied from upstream reach
98. hich influence vertical channel adjustments Small riverine impoundments may not warrant reach breaks Though Phase 1 reaches are intended to represent reference conditions large impoundments are a necessary exception to this rule as they are often too modified to de termine reference valley confinement and slope thus the reason for breaking them out as their own reaches Evaluating Stream Confinement valley width Reach breaks are often made where the valley width changes Valley width is im portant because it is an indicator of how con fined the stream is and whether it will have access to a floodplain at different flood levels To determine valley width differences look for relative changes in the distance between toes of opposing valley walls The toe of a valley wall can be identified as the bottom of the more steeply sloped portion of the valley This is evident on a topographic map as the place where the contour lines change from being widely spaced on the gentle sloped val ley floor to being more closely spaced on the 1 mar Figure 1 2 Reach break based on a change in the valley width Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 9 April 2004 steep valley wall A significant change in the confinement of the stream for example where a wide val ley transitions to a narrow valley is usually a good place to make a reach break Figure 1 3 There may be small sections of valley that are s
99. hield surveys or Phase 2 or 3 assessments Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 44 April 2004 Step 5 Instream Channel Modifications Overview Background Most of the information you have collected so far with the exception of riparian corridor land use has defined the natural fluvial geomorphic setting of the stream reaches within your watershed Before as sessing the impacts associated with instream channel modifications it is important to remember these as sumptions made for conducting these stream geomorphic assessments e Although rivers are dynamic changing their channel form or geometry continually through ero sion and depositional processes they have a central tendency of form and process that has a pre dictable relationship with surrounding watershed land forms and which may undergo significant change naturally with climate changes over time and e Human related physical change to river channels floodplains and watersheds often mimic and or change the rate of natural physical processes in the watershed Because human related changes often produce predictable channel responses we can establish reference or equilibrium conditions for different stream types and then analyze how different modifications to a channel cause a channel response adjustment or departure from the reference condition of the stream In Step 5 you will look at the instream channel modifica
100. hotos information from the NRCS and DEC Stream Alteration Engineers and windshield surveys to measure the length of the stream channel in feet that is armored either on one bank or the other Also calculate the percentage of the stream length that is armored Record the type of bank armor ing present using the menu choices Retain a paper map or digital GIS shape file of bank revetment loca tions for later use in quality assurance documentation field verification and for displaying the data Example to determine length of reach armored If 300 feet of the right bank and 400 feet of the left bank are rip rapped but 100 feet of both the right and left bank rip rap occurs along the same portion of the reach i e they overlap then you would indicate on the data sheet that the dominant bank armoring is Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 48 April 2004 rip rap and that 600 feet of the reach is armored 400 300 100 600 Given the total reach length is 2400 the percent of the reach armored would be 25 600 2400 x 100 25 Figure 5 2 Examples of Vermont stream banks hard armored with rock rip rap Note the continued erosion and bank failure upstream of the rip rap sections Base impact ratings on the percent of the reach length that has been armored If bank armoring was noted in the reach but not evaluated for the entire reach you should choose no info as the im
101. ic Assessment Tool SGAT To support the Phase 1 Watershed Assessment the Vermont Agency of Natural Resources ANR has developed a GIS extension for ArcView called the Stream Geomorphic Assessment Tool SGAT Use of GIS and the SGAT program significantly streamlines many of the Phase 1 calculations and measure ments The SGAT program automatically populates dBase tables that can be imported into the Phase 1 database The extension is set up in a user interface format however it is expected that the user has a basic understanding of ArcView Currently SGAT is designed to work with ArcView 3 x A separate handbook has been written to support the use of SGAT contact the DEC River Management Program It is recommended that a new user read through the SGAT handbook before using the tool in order to understand how the GIS extension works and which assessment steps can be completed or facili tated by the program Throughout the protocol handbook the notation SGAT is included next to those parameter headings for which SGAT can be used to measure or calculate parameter data The SGAT user handbook and the extension tool can be obtained on computer disk from the DEC River Management Program Using the GIS Reach Indexing Tool RIT There are several parameters assessed during the Phase 1 assessment that are not handled by SGAT Evaluation of some of these parameters requires identification and measurement of physical features or characteristics su
102. iers such as the Vermont Waterbody ID Though the dual numbering system described below is a bit complex this provides the flexibility needed to permit users to conduct watershed assessments at different scales at different levels of detail and at different times and still be able to mesh assessment data together into a single statewide database State Geographic Number VTID The state geographic number is the 10 digit Hydrologic Unit Code HUC plus a unique 4 digit suffix assigned chronologically as reaches are created e g 0202000303 0001 The SGAT program automatically assigns these numbers The hydrologic significance of the number is limited to the HUC prefix The primary purpose of this number is to assign every reach in the state with a unique identifier that allows all reaches to be organized in the statewide data management system This numbering convention allows you to go back identify and number reaches you may have skipped over at first without concern for keeping reach numbers in sequence from downstream to up stream You should contact the River Management Program to find out which numbers have already been assigned within the HUC 10 sub watershed in which you are working The reach numbers for your Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources gt Il April 2004 assessment will begin from the last number assigned in the HUC 10 sub watershed It is critical that you contact ANR to find out a
103. iment deposits located at the inside of meander bends choose point this menu item only if bars are greater in width than the observed wetted channel Delta Sediment deposits where tributary enters mainstream channel Multiple types of sediment deposition features in reach use only where none of the Multiple i above deposit types are dominant None No evidence of mid channel point or delta bars Unknown if there are depositional features unable to see the stream on orthophoto due No Info as i to forest cover and or inability to access entire reach during windshield survey Impact Rating for depositional features H High Numerous large unvegetated mid channel point and or delta bars present channel may appear braided L Low Some mid channel bars and intermittent large point bars NS Not Significant Typical point bars no mid channel bars present Unknown if there are unvegetated depositional features due to forest cover and or inability No Info f to access entire reach during windshield survey Naa X K A nt _Point bars on the insid of mtu L mean er bends nd Figure 6 3 Mid channel and point bars as viewed on a digital orthophoto viewed in GIS software Data Entry Use the check box in the database to indicate whether the types of depositional features and their associ ated impacts for the reach have been confirmed or changed based on wi
104. ined condition of the soil and the second letter to the undrained condition 2 In some soils that are less than 20 inches deep to bedrock the first letter applies to areas where the bedrock is cracked and pervious and the second letter to areas where the bed rock is impervious or where exposed bedrock makes up more than 25 percent of the surface of the soil The chief consideration is the inherent capacity of soil when bare of vegetation to permit infiltration Soils are assigned to four groups Group A consists of soils that have a high infiltration rate when thor oughly wet and a low runoff potential They are mainly deep well drained and sandy or gravelly Group D at the other extreme consists of soils that have a very slow infiltration rate and thus high runoff poten tial They have a claypan or clay layer at or near the surface have a permanent high water table or are shallow over impervious bedrock or other hard material Menu Hydrologic Description Group A High infiltration rate low runoff potential AID Seasonally variable high infiltration rate with low runoff potential OR undrained slow infiltration rate with high runoff potential B Medium High infiltration rate Seasonally variable Medium High infiltration rate low runoff potential Bae OR undrained slow infiltration rate with high runoff potential C Medium Slow infiltration rate C D Seasonally variable Medium slow infiltration rat
105. ing a reference stream type to each geomorphic reach in the watershed Only those stream characteristics that can be efficiently measured using maps and other remote sensing tools are evaluated in Step 2 of the Phase 1 protocols The refinement of reference reach characteristics will con tinue through the entire Phase 1 2 and 3 protocols Verification and refinement of reference stream types is done by observing sediment and hydrologic characteristics as well as channel floodplain and terrace land forms At the end of Phase 1 Step 2 you will have a preliminary reference stream type designated for each reach in the watershed If at all possible you are strongly encouraged to use the SGAT GIS extension to complete the assess ment however since GIS software and expertise is not available to all the manual does include details on how to measure the Step 2 parameters using paper maps map wheels and rulers If you have access to a computer and a mapping program such as Maptech Terrain Navigator Delorme Topo USA or Geo graphic Information System software GIS you can conduct many of these measurements on screen If you cannot do the measurements on screen try to at least obtain paper copy printouts of the VHD 1 5 000 scale digital surface water layer overlain on the 1 24 000 USGS topographic maps This will greatly en hance your data accuracy for Step 2 parameters At this phase of assessment do not expect your measurements to reflect on th
106. ining the impact ratings and characterizations that were made for sixteen of the Phase 1 parameters Since the pro tocol that follows cannot supplant field observations in evaluating stream condition you may choose to set aside the assessment of geomorphic condition Step 9 for now The value in completing this process however is that Phase 1 evaluates the parameters that may cause channel adjustment 1 e floodplain modifications or land use land cover while Phase 2 and Phase 3 assessments evaluate effects of those modifications by measuring direct signs of impacts and channel adjustment within the channel and ripar ian area Together the cause and effect factors provide a more complete picture of potential adjustment processes occurring in a reach and within your watershed As with any Phase 1 parameter observations and measurements made in the field for the same parameter should supercede remote sensing and computer generated data Values entered into the Phase 1 database should be changed if a field exercise shows they are wrong or that they mischaracterize the reach Re member to indicate where you supplant Phase 1 data with data generated from Phase 2 or 3 assessments by checking the appropriate box on the data entry form in the database As the ANR statewide database becomes populated with data generated in the field for different stream types and watersheds from around Vermont the Phase 1 impact ratings and reach condition evaluations will
107. ion Basic Methods and Skills Data Sources The information collected in a Watershed Assessment comes from three primary sources remote sensing existing data and windshield surveys as defined below The type of information source used to evaluate a parameter is listed next to each parameter in the Handbook 1 2 3 Remote Sensing Data includes data collected from maps aerial photographs and orthophotos Itis usually best to start out the assessment with at least 2 copies of the topographic maps Use one for field notes and keep a clean copy for final map notations You may need several copies to keep the maps legible Existing Data includes but is not limited to studies such as NRCS soil surveys and information such as dam locations available from the Vermont Agency of Natural Resources Other useful exist ing data such as the regional hydraulic geometry curves are included in the Appendices Existing data may also include first hand knowledge from resource specialists Windshield Survey Data includes general observations made from a car as you drive about the wa tershed These observations will help you verify information interpreted from maps and aerial pho tos Please be careful when gathering data from a car You need at least two people for this exercise one to drive and one to record observations Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources April 2004 Using The GIS Stream Geomorph
108. is table can be exported to the Soils database in which a standard report is available that sums by reach the parent surficial geologic material characteristics of each soil found in the river corridor The table automati cally highlights in gray the dominant surficial geologic material for each reach Data Entry Record the dominant and sub dominant materials and the percentages of those materials within the river corridor of each reach Use the check box in the database to indicate whether the geologic materials of the river corridor were confirmed or changed based on windshield surveys or Phase 2 or Phase 3 assess ments 3 4 VALLEY SIDE SLOPES Data Sources e USGS 1 24 000 topographic map Natural Resource Conservation Service NRCS soil surveys NRCS Top 20 soils tables available at http www vt nrcs usda gov Soils so_databases html Background Identifying the presence of steep adjacent side slopes in combination with data on the erodibility of the soils and geologic materials in the river corridor will enable you to query the Phase 1 database for information on erosion potential watershed sediment supply and potential mass failure sites Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 33 April 2004 Evaluation Using topographic maps describe the typical valley side slopes Menu on the right and left sides of the valley as viewed looking down f Classification Perce
109. ith SGAT SGAT delineates the river corridor as a polygon and then uses the corridor polygon to clip soils data from the digital NRCS soils surveys SGAT generates a table named S14SC12 which sums the soil types and dominant soil property characteristics for the four soil properties discussed above within the river corridor for each reach The table can be exported to the Soils Access database or into an Excel spread sheet for completing Step 3 5 The Soils database has built in standard reports that show the percent cov erage of each soil property characteristic in each reach s river corridor In the reports dominant soil characteristics are highlighted in gray From this report determine a reach s dominant soil characteristic for each of the four soil properties Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 36 April 2004 Geology and Aquatic Habitat The geological setting in which a stream is located influences a stream s valley form and bed and bank substrate size and erodibility These geological influences affect channel form and sediment transport processes which in turn determine in part instream habitat suitability for stream dwelling organisms Instream physical habi tat is evaluated in detail in Phase 2 In addition to these physical effects geology also largely determines a stream s water chemistry another critical component of aquatic habitat The weathering of rocks results
110. k possible alluvial fan locations on the topographic map with the symbol AF Be sure to only record an alluvial fan that occurs in the reach you are assessing and not those in tributaries entering the reach you are assessing These fans should be recorded for the appropriate reaches in those tributaries Menu Yes Maps suggest an alluvial fan exists in the reach No Maps do not suggest an alluvial fan exists in the reach Figure 3 2 Large alluvial fan indicated by series of parallel undulating topographic lines Data Entry Use the check box in the database to indicate whether the presence or absence of an alluvial fan was con firmed during windshield surveys or Phase 2 Phase 3 assessments Phase Stream Geomorphic Assessment Vermont Agency of Natural Resources 30 April 2004 3 2 GRADE CONTROLS Data Sources Field data collected during Step 7 Existing data For dam inventories or the publication Waterfalls Cascade and Gorges of Vermont Jenkins 1985 contact DEC Water Quality for copies Background Grade control as defined here is a permanent feature that may impound or slow the water upstream of the feature and limit the ability of a river to cut down into its bed These physical features provide grade control Figure 3 3 These features must be channel spanning meaning they go from bank to bank across the channel Features that provide grade control include dams and weirs bed
111. l evolution process continued to the adjustment processes that often follow degradation Such discrepancies do not neces sarily represent assessment error They are important to explore because they provide important insights into the situa tions where cause and effect did not play out as expected or where the evolution process has continued and your reach is experiencing a different adjustment process beyond what the causal factors indicate Finding out why a reach did not re spond or adjust to certain stressors as predicted or has moved to a different stage of channel evolution and or adjustment process is important to developing a management plan for the reach Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 70 April 2004 Evaluation Vermont ANR has developed a database query that adds together impact scores 2 1 or 0 for specific Phase 1 parameters that have been shown to initiate or influence different channel adjustment processes see database query flow chart in Appendix B 14 The query provides a score for each of the four ad justment processes in the Phase 1 database report titled Adjustment Process and Condition Values This report provides total impact ratings and provisional adjustment process scores for each reach sorted by channel confinement stream type and watershed size Figure 9 1 If you have elected to use the database report to score adjustment processes record your provisional
112. l questionable assessments suspect few modification activities not known Data Completed Date the protocol step was initially completed Data Updated Date the Phase 1 data for a protocol step was revised based on new or additional data sources or field assessments including windshield surveys Date of Local QA Team Review Date a quality assurance review of the Phase 1 data for a protocol step was completed by the local QA team leader Date of State QA Team Review Date a quality assurance review of the Phase 1 data for a protocol step was completed by the State QA team member Comments Any comments relaying details about the tools and materials that were used or why a confidence level was selected Document any issues things missing and why questions problems you may have had along the way Basic QA checks to be completed before sending data to the River Management Program The following list a QA checks has been developed to help you improve your QA documentation and find some of the more common errors that have been encountered during the Phase 1 quality assurance process In some cases database reports have been developed to assist with these checks Completing these checks before sending data to the DEC River Management Program will ensure a more timely State QA check 1 Print out the database report tables 1 8 Using a map of the watershed review the data to see if it makes sense gt Check to see that the slopes and stream
113. lator one that has an exponent key y Computer database software for managing data the ANR database is in Microsoft Access Pencils colored pencils and highlight markers for completing field maps Additional materials needed for using SGAT Arc View 3 1 or 3 2 SGAT extension and accompanying user handbook Digital topographic maps Digital orthophotos GIS layers for streams 1 5000 VHD where available watersheds soils and land use GIS computer tools or computer mapping programs are commercially available and are very use ful tools for measuring slopes distances and other assessment parameters however these tools are not required to complete a Phase 1 assessment Published data resources are listed throughout this Handbook Below is a summary table of sources for acquiring topographic maps orthophotos and similar basic data sources Many helpful data layers are available as GIS coverages from the Vermont Center for Geographic Information VCGI Check their website at www vcgi org Materials Source Phone Vermont Hydrography Dataset Vermont Center for Geographic Information VCGD at http www vcgi org 802 882 3000 Topographic maps Retail outlets and Vermont Geological Survey 802 241 3608 Orthophotos Vermont Mapping Program VT Dept of Taxes http www state vt us tax vermontmapping htm 802 241 3552 Surficial geologic map Vermont Geological Survey 802 241 3608
114. length for the reach Re member that this is not the same parameter as sinuosity Calculate wavelength ratio WLR by dividing the average wavelength L by bankfull channel width Wpx WLR Lm Wort Retain a paper map or digital GIS shape file of locations used for wavelength measurements for later use in quality assurance documenta tion field verification and for displaying the data Appendix H provides more background information on wavelength ratios and several examples of wavelength measurements using Vermont orthophotos Figure 6 7 Example of a reach with both regular and irregular meanders Representative wavelengths meas ured to generate wavelength ratios are circled Impact Rating for wavelength ratio H High calculated WLR is lt 6 or gt 16 L Low calculated WLR is 6 and lt 8 or gt 14and 16 NS Not Significant calculated WR is 8 and 14 N A _ Not applicable for certain stream types where 0 was entered Data Entry Use the check box in the database to indicate whether the wavelength wavelength ratio and associated impacts for the reach were determined during a Phase 3 assessment Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 62 April 2004 Step 7 Bed and Bank Windshield Survey Overview Background The Bed and Bank Windshield Survey is an essential component of the watershed assessment In this step you have the oppo
115. ley Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources 16 April 2004 Width 2 9 and Appendix E for further definition and explanation of delineating valley walls Refer to the SGAT User s Manual for information on how to create a valley wall GIS polygon layer You can manually measure and then enter data into the SGAT program for valley width length and confinement for those reaches you did not include in the valley wall GIS polygon layer Note that valley and channel slopes are generated only after manually entering reach point elevations into the SGAT program Data Sheet 2 Stream And Valley Type 2 1 DOWNSTREAM AND UPSTREAM ELEVATIONS SGAT Data Sources e USGS 1 24 000 topographic maps Evaluation Using USGS 1 24 000 topographic maps record the elevation of the upstream and downstream ends of each reach If reading elevations from computer mapping programs it is important to verify the eleva tions given by the program with those interpreted from an original USGS topographic map Not all com puter programs use corrected digital elevation models DEMs for their base map and this can lead to in correct elevations Do not assume that the elevation given by the computer is correct Also be sure that elevations on all of the topographic maps you are using are in the same units meters or feet as slope measurements will be incorrect if elevation units differ from map to map Record the elevation of the
116. ley widths are difficult to determine using remote sensing techniques it is recommended to at least nominate a valley type for every reach While there will be exceptions that will have to be corrected later the analytical power of the Phase 1 database will be much greater when provisional valley types have been assigned to each reach Evaluating With SGAT SGAT will calculate the confinement ratio with generated channel width and either generated valley widths or valley widths entered by the user Step 10 SGAT will not generate a valley type code Upon review of the data generated the user will have the opportunity to evaluate the confinement ratio and then decide on the appropriate valley type Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources 24 April 2004 Data Entry Use the check box in the database to indicate whether the confinement for the reach was determined using field measurements of channel and or valley width 2 11 REFERENCE STREAM TYPE Data Sources e Valley Slope from Step 2 3 Delineating stream types provides an initial sorting of types within large basins and allows a general level of interpretation Field check ing the remote sensing mapping effort that utilizes aerial photographs and topographic maps can lead to proper interpretations De Confinement Ratio from Step 2 10 Background Several stream classification systems have been de veloped to describe the physical characteris
117. lopments are within river corridor along 20 or more of the reach length L Low developments are within river corridor along 5 to 20 of the reach length NS Not Significant developments are within river corridor along less than 5 of reach length Data Entry Use the check box in the database to indicate whether the percent of the reach with encroachments and its associated impacts for the reach have been confirmed or changed based on windshield surveys or Phase 2 or 3 assessments 6 3 DEPOSITIONAL FEATURES Data Sources 1990 series 1 5000 Orthophotographs digital or hard copy Results from Step 7 Windshield Survey Background Bars are deposits of sediment located within the channel margins that have a height in excess of the mean water level A point bar is adjacent to the bank and located on the inside bank of a bend in the channel i e a meander bend whereas a mid channel bar is not attached to the banks has stream flow to either side of it and is generally found in straight reaches An unvegetated bar is a sign that the bar has recently been formed and is growing Mid channel bars large unvegetated point bars and delta bars may indicate an increased sediment load from upstream and the high likelihood that the streambed is actively aggrading and or undergoing rapid lateral movement The sediment source for these bars may be from bank failures or the degradation of the channel bed up stream It may al
118. ls Irrigation Irrigation for agriculture golf courses Snowmaking Ski area withdrawals Impoundment Flows regulated by dam operations Bypass Bypass channel into hydropower turbines None No known flow regulation or water withdrawals No Info Unknown if there is flow regulation or withdrawals Impact Rating for flow regulation and withdrawals High stream flows and channel geometry are affected by a cross channel weir or dam H with a water intake structure and or a visible instream impoundment that has affected sediment depositional patterns Low cross channel weir and intake structures present but there is no apparent change in channel geometry and depositional patterns NS Not Significant small water intake structure with no cross channel weir No Info Unknown if there are flow regulators L Data Entry Use the check box in the database to indicate whether the types of flow regulators and or withdrawals and their associated impacts for the reach have been confirmed or changed based on windshield surveys or Phase 2 or 3 assessments 5 2 BRIDGES amp CULVERTS Data Sources USGS 1 24 000 topographic maps hard copy or digital Vermont Hydrography Data Set VHD 1 5 000 stream coverage if you don t have access to this coverage use surface waters on USGS 1 24 000 topographic maps Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 46 April 2004 Background Strea
119. m crossing structures are often undersized to handle the stream s annual high flow events and pre sent serious impediments to less frequent flood flows Undersized bridges and culverts essentially act as dams during high water and may cause vertical and lateral stream adjustments similar to those caused by dams Undersized structures may also be inadequate to move sediment which may collect upstream in the middle of the channel causing the stream to split or bifurcate Eventually these mid channel bars push the flow to the right or left of the bridge resulting in the often sharp S bend in the channel ob served on the orthophoto This process can result in a hazardous situation if the stream outflanks the bridge or culvert during a flood and also may lead to major channel adjustments Supplemental bridge and culvert assessment protocols are included in the Stream Geomorphic Assessment program see Ap pendix G These protocols the ANR Bridge and Culvert Assessment are not required during a Phase 1 assessment but they will help in identifying structures that are potentially impacting the geomorphic con dition of stream reaches The ANR Bridge and Culvert Assessment protocols can also help you identify those structures that are impediments to fish and wildlife movement and mi gration Stream crossing structures can act as migra tion barriers to fish and wildlife that move through the stream channel or along the adjacent riparian areas Culv
120. make a note in the comments field as to why for example bank erosion seen at bridge crossing but total amount not determined so no impact chosen gt For steps 3 through 7 utilize the Update or data changed based on check boxes where data is supplemented by windshield survey Phase 2 or Phase 3 data It is important to keep track of where data has been confirmed or collected in the field by using the check boxes 3 Other parameters that can be quickly checked for potential errors gt Be sure that Sinuosity is gt 1 If not then there may have been an error in the collection of valley length Valley length is equal to or shorter than channel length The error can happen in SGAT due to the method of calculating the valley length in Step 7 Review the valley line from Step 7 and then decide the most accurate way to measure valley length The theme in SGAT does not have to be corrected but can be to reflect a new measurement Note changes in the comments field gt If LuLc for Step 4 was done by clipping the state LuLc check to see that water was not part of the data collected it may be as this is an attribute for that LuLc theme If water was part of the data you may get some corridors or watersheds where wetland came out as dominant check to see that this is the case in most cases a wetland will not be the dominant LuLc there are exceptions o Wetland may have come out dominant for LuLc when there is more wate
121. make the impact high If there are discrepancies note if there was a meander that may have been measured in Step 6 5 6 6 In some cases the assessor measured a single nice looking meander in an otherwise straightened reach For an accurate impact score assess the average condition for the reach and pass over measuring the outlier albeit regime looking meander These basic checks will help the data collector and RMP understand the limitations concerns and potential needs of the data which has been collected to date Please contact the RMP with any questions or comments as you go through your review Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources 79 April 2004 State QA reviews are greatly enhanced by providing the State QA leader with a CD containing the following data and information at the completion of the assessment All assessment data recorded on the ANR Stream Geomorphic Assessment Phase 1 Data Sheets and entered into the current version of the ANR Phase 1 Database Copies of all standard Phase 1 database output reports SGAT documentation and data sources documentation as outlined in the Phase 1 QA protocol ArcView coverages or shape files in VT state plane coordinates NAD83 of Reach sub watersheds Overall primary watershed Clipped surface water layer Reach points Phase 1 river corridor Phase 1 data from Step 3 2 Grade Controls identify locations dams and bedrock ledge that serve as gra
122. mation including interpretations of the surficial geologic materials Every soil series the basic soil subdivision has been assigned a parent material classification The parent material is defined by NRCS as the unconsoli dated material mineral or organic from which the soil devel ops Natural Resources Conservation Service 1999 Part 618 40 Geologic materials can also be determined from the surface geologic maps produced by the Vermont Geological Survey though these maps are at a fairly coarse scale De scriptions of geologic materials and sources of geologic information are provided in Appendix F Evaluation For each reach record the dominant type of surficial geologic material also called parent material found within the river corridor See Appendix E for instructions on delineating the river corridor To do this overlay the river corridor on the NRCS soil survey maps and determine the parent material type that covers the most area within the reach s river corridor Estimate and record the percent of the river corridor area covered by the dominant parent material type Exclude the area covered by water the river or stream within the river corridor polygon from the total corridor area when estimating the percent area Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 32 April 2004 covered by the dominant parent material type If another parent material type constitutes at least 25
123. may be sensitive to further modifications For instance two water sheds with similar valley shapes geology and soils may have very different sized streams due to mark edly different amounts of vegetative cover next to their channels or within their watersheds A relatively narrow deep riffle pool stream may become very wide and aggraded filled in with sediment if the ri parian vegetation is removed Evaluation You will interpret changes in run off characteristics in the steps below using the data sources listed be low You may also have first hand knowledge of land cover land use changes that you want to consider when interpreting map and orthophoto information Remember to revise the Phase 1 data where wind shield surveys and Phase 2 and 3 assessments give you first hand knowledge of the land use land cover along a reach Although both digital and paper map data sources and evaluation techniques are described below it is highly recommended that you secure the resources and expertise needed to undertake watershed LcLu analysis using GIS software and digital data layers Even if you need to purchase printed maps that show the most recent LcLu coverage and or orthophotos with your reach breaks and watershed boundaries overlain the monetary investment is well worth the time saved in reviewing and piecing together water shed land cover from several paper copies of aerial and or orthophotos Ideally LcLu analysis will be conducted using SGAT
124. modifications are likely or may be subject to head cutting from downstream reaches Hish Stream type and condition very sensitive to change or future reach and watershed 8 modifications are likely or subject to head cutting from downstream reaches Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 75 April 2004 Step 10 Like Reach Evaluation Background The purpose of a Like Reach Evaluation is to group reaches in the watershed by similar stream types product of Step 2 and similar geomorphic condition assessments product of Step 9 Grouping streams by like reaches is useful in selecting a manageable number of reaches for which to conduct the more detailed Phase 2 and Phase 3 assessments By collecting detailed information on a few reaches that represent all the stream types in your watershed you are better able to characterize the entire watershed without conducting extensive and time consuming field surveys on the entire watershed Evaluation The database report titled Phase 1 Like reach sorted by stream type condition and watershed size assists with the evaluation of like reaches by creating the following table Number Type Size prazss 1 ha pbo b P b h D Rime T4 5 1 A 2 06 4 2 0 0 0 1 Reference mo h e ha foe 2 h p 2__ Referee ma ho e bha hp p p p M Mem m e e he o e e e e ea mo ho k ma h p hb p h Pow 2 Good praas
125. n surveys Background Bank revetments intended to fix stream channels in place often contribute to channel movement and adjustment This is because revetments are typically applied to the symptom of bank erosion while the underlying channel adjustment processes that are causing the bank erosion are overlooked Attempts to lock in the vertical and lateral position of a channel while it is under adjustment may set back the channel adjustment process prolonging or preventing recovery of the stream channel back into a state of equilib rium or imposing a new state of equilibrium dependent upon the stream type and the maintenance of the armored condition Furthermore many revetments typically fail and or cause further channel adjustments to propagate upstream or downstream This is especially true where a stream has vertically incised or cut down into its stream bed losing access to its floodplain Where this channel adjustment process is oc curring rock rip rap frequently becomes undermined fails and then contributes to aggradation and wid ening of the channel Bank armoring also called revetments can be made from natural material such as whole trees or stumps or wooden cribs filled with stone and willow shoots Typically in Vermont bank revetments have been made of rock rip rap to protect the bank from scour and undercutting particularly along the outside bends of channels where the current is the strongest Evaluation Use the orthop
126. n the range of natural variability ex pected for the reference condition of the stream Fair Streams in fair condition are fully in ad justment possibly already experiencing or heading The database generates a within watershed toward major and rapid changes due to recent reach condition score from the provisional adjust floodplain and channel modifications land cover ment process scores using the following formula changes and or loss of riparian buffer Channels undergoing incision i e head cutting widening Condition Score or rapid lateral movement i e planform adjust ment should score in fair condition HS deg HS aggr HS wid HS plan 4x HS Poor An entrenched reach for instance in a nar Where row or unconfined valley Stage II of channel evo lution Appendix C or one that is severely over HS Highest adjustment process score widened and out of regime with respect to sedi for any reach in your watershed ment transport i e aggrading should be evalu deg reach degradation score ated as a reach in poor condition Unless the aggr reach aggradation score stream has started to braid with large mid channel wid reach widening score bars that can be seen on the orthophotos it may be plan reach planform score difficult to know whether the stream is in fair or poor condition without further field assessments In the example shown in Figure 9 1 a value of 10 was
127. nd Step 3 5 Soil Properties The River Corridor From Step 3 on you will be evaluating several parameters within the river corri dor which is described in detail in Appendix E SGAT delineates the river corridor based on valley walls meander centerlines and standard buffer algorithms built into the software Appendix E explains the general process that SGAT uses to draw the river corridor and the rationale behind the river corridor delineation process Data Entry SGAT creates the data for Steps 3 3 and 3 5 in a dBase table that can be opened in Excel or imported into the Soils Access database for evaluation The Soils database is separate but associated with the Phase 1 database and contains standard data reports that detail the dominant surficial geologic material Step 3 3 and values for four key soil properties Step 3 5 within the river corridor for each reach Users can re view the data and choose the appropriate values to enter into the Phase 1 database DATA SHEET 3 BASIN CHARACTERISTICS GEOLOGY AND SOILS 3 1 ALLUVIAL FAN CHANGE IN VALLEY SLOPE Data Sources e USGS 1 24 000 topographic map Background An alluvial fan may form where a steep confined stream valley becomes abruptly less confined and shallower in slope When the stream becomes shallower it loses velocity which reduces its ability to transport sediment The sediment drops out of the water blocking the channel and leading to frequent shift
128. nd number following the tributary number e g T3 01 is assigned to the first reach on the 3 major tributary up the mainstem M S designates minor tributaries to the mainstem river those comprising less than 10 of the watershed at their confluence with the mainstem e g MO2S2 is assigned to the second minor tributary on the mainstem that flows into mainstem reach M02 Minor tributaries are numbered sequentially from downstream to upstream however the S sequence starts over for each main stem reach For example the first two minor tributaries entering into the mainstem reach MO1 would be MOIS1 and MO1S2 and the first two minor tributaries entering into reach M02 would be MO02S1 and M0252 M T S designates minor tributaries to the major tributaries Additional S letters are added as needed to designate tributaries of tributaries of tributaries etc Individual reaches on minor tribu taries are designated with a period and number following the tributary number For example MO03T1 02S1 04 represents the fourth reach of the first tributary that flows into the second reach of the first major tributary which flows into the third reach of the mainstem When starting the assessment it is essential to determine all mainstem reaches and to label at least all the major and minor tributaries to the mainstem M T and M S at the HUC 10 scale before starting to collect other data Even if you plan to complete a Phase 1 assessmen
129. ndshield surveys or Phase 2 or 3 assessments Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 57 April 2004 6 4 MEANDER MIGRATION CHANNEL AVULSIONS Data Sources Current and historic orthophotos digital or hard copy Aerial photographs Results from Step 7 Windshield Survey Background A migrating channel moves by eroding the outer banks of its meander bends such that the channel s bends move sideways and downstream over time Some amount of lateral migration is natural in most alluvial streams systems but the rate of migration may be increased in streams that are out of balance with their watershed inputs A bifurcated or braided channel is one that has split into two or more active channels An avulsed channel is one that has suddenly changed location and cut a new section of channel within its valley abandoning the old section of channel which may appear as a dry river or long narrow wetland on the valley bottom Channels change course for various reasons Streams often undergo dramatic migrations and avulsions due to changes in the sediment supply and or sediment transport capacity of the channel Sediment build ing up on the channel bed can force flows laterally to the outside of a channel bend eroding even the most stable stream banks migration or can divert flow to the inside of a channel bend cutting off entire meander bends avulsion Streams can change course as the result of cat
130. nel cross sectional area width and depth have been developed by the River Man agement Program Appendix J At this time the curves are recommended for estimating channel width only on streams and rivers that are similar to those from which the curves were developed This would include mid to large sized streams in unconfined moderate gentle gradient alluvial settings You should not rely on the curves to characterize channel dimensions for other types of streams throughout your wa tershed The HGC for channel width follows the equation below where X is drainage area in square miles To calculate channel width in feet take the watershed size in square miles calculated in section 2 7 to the 0 50 power using the y function key on your calculator then multiply this value by 10 18 Round the calculated value to the nearest foot Example Calculating Channel Width W 10 18 X where X drainage area in sq mi if X 20 sq mi then W 10 18 20 45 feet For some stream reaches field data exists from surveys that may have included measurements of bankfull channel width Check for stream related studies and other developments that would have involved cross sectional surveys You should consider all Phase 1 channel width data to be provisional until you can go into the field and measure reference channel width After conducting a Phase 2 assessment you can up date the Phase 1 value for channel width in the Phase 1 d
131. ngth for those reaches where you digitize valley walls For those small tributaries or streams in confined valleys where you cannot determine valley walls you will need to manually measure valley length using the procedure described above and then enter your measurements into SGAT Step 10 Data Entry Use the check box in the Phase 1 database to indicate whether the valley length was determined during a Phase 3 survey assessment Phase Stream Geomorphic Assessment VT Agency of Natural Resources 18 April 2004 2 3 VALLEY SLOPE SGAT Data Sources e USGS 1 24 000 topographic maps hard copy or digital Evaluation Using the reach endpoint elevations recorded in 2 1 subtract the reach s downstream elevation from its upstream elevation to get the change in elevation for the reach Next divide the change in elevation by the reach valley length recorded in Step 2 2 to calculate the reach valley slope Multiply the valley slope by 100 to get percent slope Example Calculating Valley Slope 1140 ft upstream elevation 1000 ft downstream elevation 140 ft change in elevation difference in elevation ft 140 0 035 x100 3 5 valley slope length of valley ft 4 000 Evaluation with SGAT SGAT will calculate the valley slope based on the reach endpoint elevations entered and the reach valley length which is either generated by SGAT or entered by the user Data Entry If you did not enter upstream and downstream
132. nt Slope stream using the categories provided in the menu table Valley slopes can be measured off of USGS topographic maps in the Flat 0 3 same way as described for calculating valley and channel slopes Hilly 4 8 in steps 2 3 and 2 5 Use the Windshield Survey Step 7 to ver Steep 9 15 ify valley side slope data Very Steep 16 25 Extremely Steep gt 25 The NRCS soil surveys Figure 3 4 are also useful for estimat ing valley side slopes The last letter in the three letter abbreviation for soil types indicates the slope of the land For example on a soil survey map a soil polygon may be labeled BeC which is a Berkshire Be soil with a C slope The breaks between the various NRCS slope classes vary between soil series Thus in one soils series an A may range from 0 to 2 while in another an A slope may range from 0 3 There are guides in each NRCS soil survey explaining different soils and their properties With a GIS program digital topographic maps can be overlain using the DRG Tools extension onto the digital soils layer Since each soil type has a slope range using the soil slope values in conjunction with the topographic lines will result in a more accurate evaluation of valley side slope Link the attribute table of the soils layer with the NRCS Top20 table to determine the slope range of each soil type 3 5 SOIL PROPERTIES SGAT Data Sources Natural Resource Conservation Service NRCS s
133. ntered by the use and the reach channel length generated by the software Data Entry If you did not enter upstream and downstream elevations in Step 2 1 use the Gentle Gradient check box on the data sheet to indicate channel slope Use the check box in the database to indicate whether the channel slope was determined during a Phase 2 or Phase 3 assessment 2 6 SINUOSITY SGAT Data Sources Step 2 2 and 2 4 results Evaluation Sinuosity is the ratio of channel length to valley length Divide the channel length measured in Step 2 4 by the valley length measured in Step 2 2 Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources 20 April 2004 Example Calculating Sinuosity channel length ft 6000 4000 1 5 sinuosity valley length ft Evaluation with SGAT SGAT will calculate sinuosity from the software generated channel length and either the generated valley length or the valley length entered by the user If SGAT generates sinuosity values less than 1 there may be an error in how the valley length measurement was generated in the program Measure the valley length on screen to determine if a different value should be entered for valley length The new valley length value can be entered in SGAT Step 10 and a new sinuosity can then be calculated Data Entry In general the narrower the valley the closer the stream length is to the valley length with them both becoming nearly equal in length in
134. of the river corridor enter that material on the data table as the sub dominant geologic material for the reach To determine parent material type from the NRCS soil surveys you will need to first use the soil map key and accompanying tables to determine the parent material type for each soil type in the river corridor Then add up the area covered by soil types with the same parent material type to determine which parent material type covers the most area within the river corridor Bedrock outcrops can be determined through windshield surveys and existing data including the bedrock and surface geologic maps see Appendix F Menu as Soils ate Material Description Top 20 Table Codes Erodibility 1 Alluvium Alluvial river sediments A alluvial High 1 Ice Contact Glacio fluvial glacial river deposits GF outwash High 2 Glacial Lake Glacio lacustrine glacial lake deposits GL lacustrine Moderate High 2 Glacial Sea Glacio marine glacial sea Moderate High X DT dense till 2 Till Till glacially deposited sediments GT glacial till Moderate High 3 Colluvium Rock fall and landslide deposits Variable 3 Bedrock Bedrock Low Other M miscellaneous O organic deposits Evaluation with SGAT SGAT delineates the river corridor as a polygon and then uses the corridor polygon to clip soils informa tion from the NRCS soils maps From this SGAT generates a table named S14SC12 Th
135. of channel migration bifurcation and or channel avulsions along reach evident in historic orthophoto comparison Low Few occurrences of channel migration bifurcation or avulsions evident in historic L orthophoto comparison NS Not Significant No channel migration bifurcation or avulsions evident No Info Unknown if there are channel migrations bifurcations or avulsions due to forest cover and or inability to access entire reach during windshield survey Data Entry Use the check box in the database to indicate whether the type and degree of channel migration and its associated impacts for the reach have been confirmed or changed based on windshield surveys or Phase 2 or 3 assessments 6 5 MEANDER WIDTH RATIO Data Sources 1990 series 1 5000 Orthophotos digital or hard copy Background The meander belt width is the horizontal distance between the opposite outside banks of fully developed meanders determined by extending 2 lines one on each side of the channel parallel to the valley and parallel to each other from the lateral outside extent of each meander bend along both sides of the chan nel Figure 6 5 The meander belt width can change radically within a reach due to channel constrictions from floodplain encroachment surficial and bedrock geology small changes in valley slope and other factors Uncon fined gravel based streams in shallow sloped valleys that are in regime have belt widths
136. of like reach evaluation database report 76 Tables Table Number Description Page Table 1 1 Guide to valley slopes 10 Table 1 2 Parameters and map codes for watershed orientation surveys 14 Table 2 1 Confinement ratios 24 Table 2 2 Phase 1 Reference Stream Typing Chart 26 Table 7 1 Phase 1 parameters benefiting from field verification 63 Phase 1 Stream Geomorphic Assessment April 2004 iii VT Agency of Natural Resources Appendices Appendix Description Page Appendix A Phase 1 Data Sheets Al Al15 Appendix B__ Database Instructions B1 B21 Appendix C Channel Evolution Models C1 C4 Appendix D Watershed Area Delineation Using Topographic Maps amp Aerial D1 D11 Photography Appendix E River Corridor Delineation Process E1 E9 Appendix F Geologic Information F1 F4 Appendix G Phase 1 amp 2 Bridge and Culvert Survey Protocols G1 G22 Appendix H Meander Geometry H1 H3 Appendix I Stream Classification Systems 1 12 Appendix J Vermont Regional Hydraulic Geometry Curves J1 J5 Appendix P Submitting and Retrieving Data from the State Geomorphic Database P1 P5 and Using the Reach Indexing Tool with SGAT Appendix Q Glossary of Terms Q1 Q10 The Vermont ANR Stream Geomorphic Assessment Handbooks Phases 1 through 3 have a shared set of appendices Not all appendices are included with the Phase 1 Handbook Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources 1V April 2004 P
137. oil surveys e NRCS Top 20 soils tables available at http www vt nrcs usda gov Soils so_databases html Background Similar to geologic materials soils information contributes to the understanding of sediment regime and may be particularly useful in explaining the channel condition stream type and departure and the ad justment processes occurring in a reach In addition knowing the types of soil and their properties within the river corridor may be valuable in an assessment of water quality where soils are subject to erosion during stages of channel evolution There are several categories of information contained in the NRCS soil surveys that are particularly useful in watershed analysis These include detailed information on engineering properties of the different soil types such as permeability grain size hydrologic group depth to bedrock and depth to seasonal high water table Soils information can help to characterize the erodibility of the soils the ability of water to infiltrate into the soils and the ways in which the soils were created Evaluation Overlay the river corridor see Appendix E on the NRCS soil survey map Within the river corridor of each reach determine the dominant characteristic for each of the four soil properties discussed below hy drologic group flooding erodibility and depth to water table To determine the dominant soil characteristics of each soil property you will need to first use the soil map k
138. omewhat narrower or wider than the average valley width for a given stretch of stream If the section is less than a mile long it may not be necessary to break it out as its own reach but rather to lump it within the larger section of stream Use your judgment If the section is significantly narrower or wider make a reach break no matter how long the resulting reach is Evaluating Valley Slope Another important valley characteristic to consider when defining reaches is the slope of the valley To visual ize the valley slope look at the dis tance between contour lines that cross the stream and valley floor Very Steep lt 0 2 in Widely spaced contour lines indi Steep 0 2 0 5 in cate a gentle slope and tightly ce Moderate gt 0 5 in spaced contour lines indicate a steeper slope Make reach breaks where there is a substantial change in the valley slope If there is only a short section of valley less than 1 4 mile which has a different slope than the rest of the valley it may not be necessary to break out that section as its own reach Table 1 1 Guide to valley slopes in defining first cut stream reaches Percent Slope Description of Approximate contour in slope terval spacing on 1 24 000 map Gentle gt I in Another indication of valley slope and confinement is channel sinuosity which is a ratio of channel length to valley length Changes in channel sinuosity can be determined on topographic maps Gener
139. or aquatic insects fish and other biota and potentially even smothering fish and salamander eggs and young Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 65 April 2004 Evaluation Bank erosion is evident by the presence of bare soil extending up the bank fallen vegetation or slumped soil at the base of the bank or undercut fractured banks that look like they are going to fall off into the river Mark the presence of bank erosion on the map with the letters BF and record the percent of the reach stream length that is experiencing bank erosion along one or both banks Note Do not double count the stream length where erosion is occurring on both right and left banks Retain a paper map or digital GIS shape file of bank erosion locations for later use in quality assurance documentation field verification and for displaying the data Menu Bank Erosion Description High Bank erosion observed along gt 30 of the reach length Low Bank erosion observed along lt 30 of the reach length None No bank erosion observed No Info Unknown if there is bank erosion Estimate the average height of outside banks or highest banks against which the deepest water thalweg is flowing Bank height is important for assessing the potential for bank failure and landslides Menu Bank Height Description High gt 15 ft from streambed to top of bank or slope Medium 5 15 ft
140. ot want to change reach breaks once you have digitized sub watersheds for these reaches Be sure to give careful thought to your reach breaks and use the Watershed Orientation to quickly verify them in the field The Watershed Orientation is particularly helpful in identifying valley walls and in understanding valley slope and confinement Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources April 2004 By the end of Step 2 you will have assigned each reach a reference stream type classification as de fined in the Program Introduction The following discussion offers general guidelines for determining reach breaks and evaluating valley form geology and tributary influence to define distinct geomorphic stream reaches Ground Rules for Defining Reaches Stream reaches designate a length of channel based on reference stream type characteristics that can be distinguished in some way from the reaches immediately upstream or downstream You are encouraged to verify initial reach breaks in the field during the Watershed Ori entation to see if your visual first cut of reaches makes sense on the ground During Phase 2 and Phase 3 field assessments additional stream type characteristics beyond the Phase 1 parameters of stream size geology valley confinement and valley slope may influence where you decide to make reach breaks ei ther dividing or combining reaches based on your field observations and measurements For r
141. oto with the same landmarks on the recent photo silo cross roads V shaped intersec tion Using a different colored pencil trace the course of the river and all abandoned channels onto the tracing paper ws Compare the recent and historic channel locations to iden tify areas of extensive channel migration and channel avul sions Since the late 1930 s at least eight complete state wide sets of aerial photos have been taken over Vermont Since the late 1970 s these photos have been orthogonally corrected see list in Appendix D Photos earlier than the EF z 1970 s series can be used to further examine channel 1979 Location white movement and meander migration ee Locatton black BN Menu i Channel has migrated by eroding its Migration outer banks on meander bends x Stream flow has split into two or more Bifurcation active channels A Channel planform has changed due to vulsion meander cut offs More than one of the above in the Multiple reach use only where none of the above planform change types are dominant None None of the above Unknown if there are channel migrations or avulsions unable to see the stream No Info on orthophoto due to forest cover and or inability to access entire reach during windshield survey Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 59 April 2004 Impact Rating for meander migration High Frequent occurrences
142. our team examines enough of the watershed to interpret the impacts associated with upstream and downstream activities Final Products of the Phase 1 Watershed Assessment Products of a Phase 1 Watershed Assessment include 1 Reference Stream Typing which involves dividing streams in the watershed into geomorphic reaches that are assigned a reference stream type based on physical parameters such as geology valley landform and valley slope Note These are NOT the stream types as described in the Ver mont Water Quality Standards classification scheme Water Resources Board 1999 2 A Stream Impact Rating that results in a priority ranking for each reach in your watershed Step 8 This is based on impact scores that you assign to channel floodplain and land use modifications for each reach as you progress through the assessment Reaches with high scores may be physically re sponding to disturbances and warrant further study in the field Reaches with very low scores may also be candidates for field assessment as they may be suitable reference reaches for streams in ad justment 3 A Provisional Geomorphic Condition Evaluation for each reach Step 9 that includes Reach Condition a descriptor that represents an estimate of channel and floodplain change or de parture from the reference condition given the types and extent of channel floodplain and land use modifications documented in the watershed Channel Adju
143. pact rating Be sure to note in the comments field the reason for choosing no info as this will need to be updated once the reach has been field evaluated Streambank condition surveys have been a popular water resource assessment activity for decades Check with NRCS and the Regional Planning Commission in your area to see if streambank surveys which include erosion and bank revetment mapping have been completed This information may be use ful here You may even consider having a couple summer interns complete a streambank survey Menu Rip rap Rock or stone rip rap Hard bank Concrete or other hard bank treatments Multiple Multiple bank revetments Other Other bank stabilization including tree revetments and log cribbing INone No bank armoring in the reach No Info Unknown if there is bank armoring in any part of the reach Impact Rating for human placed bank armoring H High Greater than 30 of the reach length is armored L Low Between 10 and 30 of the reach length is armored NS Not Significant Less than 10 of the reach length is armored Bank armoring has not been evaluated for the entire reach and im pact at the reach level is unknown No Info Data Entry Use the check box in the database to indicate whether the type and extent of bank armoring and its associ ated impacts for the reach have been confirmed or changed based on windshield surveys or Phase 2
144. r stream then makes up the corridor In many instances if you had chosen wetland as dominant and you look at the map and see that it is not true the dominant LuLc may be what was chosen as the subdominant o The new 2004 LuLc soils database reports reflect that water areas have been clipped so if there is any question new reports may be appended to your database for reviewing the data gt Also check to see that the LuLc for Step 4 1 watershed LuLc was summed for the entire watershed upstream of a reach break and not just for the sub watershed of the reach This can be done by opening the table imported into the LuLc soils database for Watershed LuLc Once open there will be a field named sumlevel The sumlevel should be upstream if not then the data for Step 4 1 is incorrect If incorrect The LuLc for Step 4 1 is generated by running the LuLc clipped at the sub watershed through Steps 11 12 13 and 14 in SGAT 4 Some parameters that should be compared for consistency gt Comparing values in steps 5 4 6 5 and 6 6 For Step 5 4 if you chose a high impact for channel modification that is 30 of reach was modified then the impact score for steps 6 5 and 6 6 should also be high these measurements are only done for C E streams For step 6 5 and 6 6 no measurement is taken if more than 50 of the reach is straightened the channel width will be entered for the values in step 6 5 and 6 6 this will
145. r the assessment and should only be considered when project goals demand a high level of accuracy for location data as data collection and management can be time consuming See http www dnr state wi us maps gis documents gps_tools pdf for information on how to use GPS Take good pictures to document unique features such as grade controls and general watershed charac teristics such as channel size and valley form throughout the watershed Be sure to record the number of the picture and the location that it was taken using the standard photo log form Appendix A If you change roles of film mark the roll with tape as to which area locations the roll represents and be sure to transfer this information to the envelope in which you submit your film for processing Reference these pictures when completing the rest of the assessment Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 14 April 2004 Step 1 Reach Location Overview Once the geomorphic reaches have been delineated and numbered as described in the previous section you are ready to begin the first step in the Phase 1 assessment process which is to formally locate your reaches Locating the reaches involves writing a location description identifying the Vermont municipal ity in which the reach is located and providing a latitude and longitude for the upstream and downstream ends of the reach Reach location information serves of purpo
146. rces 73 April 2004 of the change in condition This information does not show up in the report but is included here to dem onstrate how the data can be interpreted There are a couple Phase 1 Phase 2 data comparisons in Figure 9 2 that are noteworthy Reach M3 was evaluated in both Phase 1 and Phase 2 assessments as being in good condition with slight aggradation After taking width and depth measurements however the reference stream type was determined to be an E type stream This refinement would result in a revision to the Phase 1 database entry for stream type Step 2 10 Little or no impacts were noted for reach M7 during Phase 1 resulting in a reference condition being provisionally set Phase 2 assessments discovered a large new influx of sediment was re sulting in substantial aggradation in the reach and the condition description was switched to fair Orthophotos have only been produced once each decade and many activities that would affect channel adjustment and condition i e those you would normally see during remote sensing as sessments will only be observed once you go into the field Windshield surveys and Phase 2 as sessments will help you pick up these discrepancies In this case you would revise Step 9 descrip tors of adjustment condition and sensitivity in the Phase 1 database and indicate that the changes were based on Phase 2 field observations Reach 19 was provisionally determined in Phase 1
147. reach have been confirmed or changed based on windshield surveys or Phase 2 or 3 assessments 6 2 RIVER CORRIDOR DEVELOPMENT Data Sources USGS 1 24 000 topographic maps digital or hard copy 1990 series 1 5000 orthophotos digital or hard copy Emergency 911 GIS coverage available from VCGI website at http www vcgi org Background Development encroaching on the floodplain and river corridor may result in a confinement of flood flows as described above in section 6 1 and may also effectively decrease the lateral extent to which the outside meanders of a stream can migrate away from one another The extent to which a channel migrates later ally as measured by the distance between the outer limits of its meander bends on opposite banks is called the meander belt width and is described further in section 6 5 Decreasing the meander belt width of a channel may limit the ability of the channel to adjust to changes in channel slope thereby lead ing to an increase in channel slope which in turn can lead to bed degradation as stream power increases potentially triggering a channel evolution process Appendix C Houses and other structures that en croach into the river corridor and floodplain may represent a flood hazard and may in addition pose threats to infrastructure invest ments and habitat downstream due to the increased flood velocities and stream power if the encroachments result in a confined and steeper
148. ream Alteration Engineers Background Berms and roads and the hardened embankments often used to protect them limit the lateral adjustments of the stream within the corridor and may contribute to onset of vertical adjustments within the channel Developed land including highways roads and railroads in close proximity to the stream may be a clue that the stream bank has been bermed to protect the infrastructure and investments For instance after the 1973 flood many berms or levees intended to elevate the stream embankment to prevent flooding of ad jacent lands were built In some places trees have grown on these berms and are young forests about 25 years old Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 53 April 2004 Evaluation Visually estimate the percentage of the river corridor length along which berms roads railroads or improved paths run parallel to the stream on either bank see Appendix E for river corridor de lineation Indicate whether these floodplain encroachments occur on the right bank RB left bank LB or both as determined facing downstream Berms are difficult to identify on ortho photos and are best identified as part of the Step 7 windshield survey or through other data sources such as flood damage remediation reports Write None if you know there are no berms roads rail roads or improved paths as defined in Glossary Appendix Q in the river cor Figure
149. rock waterfalls and ledge drops that span the width of the river channel Grade control is important because it keeps the base elevation of a river from being lowered When the base elevation is lowered several adjustments typically occur bed forms such as steps and riffles are eroded and floodplain access may be lost vertical channel adjustments propagate upstream causing channel incision and bank erosion the channel widens during floods introducing sediment into the river system from bank erosion the water table may lower affecting channel flows riparian vegetation and domestic wells and human investments particularly roads and bridges can be undermined Some grade controls may serve as barriers to movement and migration of aquatic biota Dams weirs and falls may prevent the upstream and in the case of some dams downstream movement of stream dwelling organisms particularly fish Phase 1 results for grade controls can be used to guide further assessments of aquatic habitat connectivity in Phase 2 Bridge and culvert assessments are also important components of assessing aquatic habitat connectivity see Appendix G ANR Bridge and Culvert Assessment proto cols Vermont Fish and Wildlife Department fisheries biologists can provide information about known fish migration barriers and can help evaluate suspected barriers Evaluation Indicate known dams weirs waterfalls or bedrock ledges that completely cross the channel Mark
150. rs but rather the location and rate at which it occurs Henderson and Shields 1984 define natural erosion as the processes that occur without significant hu man activities in the drainage basin or catastrophic natural events such as volcanic eruptions or forest fires They define accelerated erosion as erosion that is atypically high in magnitude and is different in nature than the erosion experienced at the site or reach in question in the recent past Both natural events e g high flows and human activities e g changes in land use can cause accelerated erosion Johnson and Stypula 1993 Accelerated bank erosion is both a symptom and cause of channel adjustment processes High vertical banks with low root density and a high percentage of non cohesive fine grained sediments i e sand and gravel have the highest potential to erode Eroding banks may not only change the cross section of the channel where they occur but they can contribute to aggradation and other channel adjustments down stream adding tons of sediment to stream reaches that are depositional and sensitive to an imbalance in the sediment load Bank erosion can be an important source of sediment to a stream system over time however rapid and extensive bank erosion can result in large quantities of sediment entering a stream system potentially threatening aquatic habitats and biota Fine sediments can embed gravel and cobble stream bottoms re ducing available habitat f
151. rtunity to field verify the reaches you have described using maps and other remote sensing techniques Even though you will not be able to see all reaches from the roads you may be able to see enough to assess certain parameters and pick out obvious problems and or verifications of Phase 1 data You may also choose to float larger low gradient rivers and streams by canoe to complete the windshield survey as this is an efficient way to see a lot of the stream system in a short period of time Evaluation The main focus of the Windshield Survey is to field check Phase 1 data collected so far as well as note the condition of and materials that make up the stream bed and banks Based on the amount of time you have and figuring on an average of 30 minutes per stop including drive time plan your driving route and stops to ensure that you survey a good representation of the different stream types in the watershed Be aware that the bed and bank conditions at or near the road crossing may not represent the conditions of the reach as a whole As discussed in Step 5 2 bridges and culverts may have profound impacts on the fluvial processes and geomorphic conditions of the stream reaches To further evaluate the potential im pacts of road crossing structures on geomorphic and habitat conditions and connectivity of the watershed use the ANR Bridge and Culvert Assessment protocol and field forms Appendix G Before you begin your windshield survey print out
152. s and may have long stretches of featureless bed Occur in moderate to low gradient and moderately sinuous channels generally in unconfined val Riffle Pool leys and have well established floodplains Channel has undulating bed that defines a sequence of riffles runs pools and point bars Dune Ripple Usually associated with low gradient and highly sinuous channels Dominated by sand sized sub strates Channel may exhibit point bars or other bed forms forced by channel geometry Typically undulating bed does not establish distinct pools and riffles Multiple channel system found on steep depositional fans and deltas Channel gradient is gener ally the same as the valley slope Ongoing deposition leads to high bank erosion rates Bed fea Braided tures result from the convergence divergence process of local bed scour and sediment deposition Unvegetated islands may shift position frequently during runoff events High bankfull widths and very low meander belt widths Bedrock Lack a continuous alluvial bed Some alluvial material may be temporarily stored in scour holes bac ena or behind obstructions Often confined by valley walls No Info Dominant bed form is unknown Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources April 2004 64 Be careful as casual observations of dominant bed material type are often biased toward the larger parti cles If you can get down close to the stre
153. s use the space provided in the Phase 1 database to re enter the reference stream type that you set provisionally using only remote sensing techniques This may be a valuable quick reference for you in understanding the setting of the reach For instance noting that a stream was thought to be a B step pool based solely on map interpretations will help you discern the small mountain C4 stream from the C4 located in a broad valley at a lower elevation Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources 26 April 2004 Stream Types and Aquatic Habitat As indicated in Table 2 2 stream types are associated with specific bed forms and valley characteristics which determine in part the types of habitat available for stream dwelling organisms In general different species utilize different stream types as they have adapted to specific physical chemical and biological components found in these different stream types Many species will utilize more than one stream type but few species are adapted to utilizing all stream types well Some generalizations can be made about what species you might expect to find in certain stream types For example the Northern Spring salamander Gyrinophilus porphyriticus commonly inhabits very cold well oxygenated headwater streams and spring seeps which are usually associated with A type and possibly B type streams The physical characteristics of A and B stream types that contribute to k
154. s considered the primary watershed and includes all the land area that contributes flow to the as sessment stream s Draw this watershed boundary on USGS topographic maps as described in detail in Appendix D Refer to the SGAT User Manual on how to develop a digital watershed data layer 2 Selecting Assessment Streams Once you have determined the primary watershed you are going to assess you need to identify the main stream or river in the watershed and the major tributaries of that stream for which you will complete the Phase 1 assessment It is helpful to delineate the boundaries of the sub watersheds for each major tribu tary to gain an understanding of what percentage of the watershed those tributaries comprise Your as sessment goals and available resources should be considered when deciding how many tributaries to evaluate in the watershed In general the tributaries that contribute 10 or more of the primary water shed area should be assessed If resources are limiting you can delay conducting steps 1 through 10 of the assessment for some tributaries but you should define and number reaches for all of the mainstem and the tributaries that you plan to include in the assessment over the long run 3 Defining Geomorphic Stream Reaches A Visual First Cut Next for those streams you have selected for assessment define geomorphic stream reaches based on the geomorphic characteristics of stream size valley characteristics
155. s in channel loca tion Viewed from above an alluvial fan often has the shape of a wedge of pie with the narrow point at the upstream end where the confined valley widens out see Figure 3 2 In Vermont these fans can range from a few tens of feet to several hundred feet or more across Excavations on alluvial fans in Vermont show that al though much of the material accumulated in the first few thousand years after the end of glaciation sediment accumulation increased dramatically on many fans in the M PANAY Figure 3 1 Potential locations pa Sni alluvial fans on tributaries located on a topographic map where the valley changes from a steep confined setting to a shallow unconfined setting Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 29 April 2004 19th century in response to the large scale land clearing associated with increased settlement throughout Vermont Bierman et al 1997 and Jennings et al 2003 Since the reforestation of much of Vermont s landscape in the late 19th century and the 20th century sediment accumulation on the fans has decreased Evaluation It is difficult to determine from map work alone if the reach has formed on an alluvial fan This parame ter is meant to assess the possibility that the reach is located on an alluvial fan A yes answer to this question indicates that further field work may be required Figure 3 1 shows several possible alluvial fans Mar
156. se of helping you and others find the reach on the ground dur ing windshield surveys and later phases of Stream Geomorphic Assessment The process of sorting mapping retrieving and collating Phase 1 data is also facilitated by reach location information Data Sheet 1 Reach Locations 1 1 REACH DESCRIPTION Evaluation The reach description should help someone unfamiliar with the area to locate the reach Try to provide as much detail to your description as you can for example give a distance and compass heading from a named landmark road crossing or road mile marker to the upstream end of the reach All reaches should be marked on a topographic map and labeled with reach numbers Example Reach M1 Off Rt 100 2 miles up from Rt 100 Bridge St intersection in Granville Reach begins NE approximately 1 2 mile off Rt 100 just above tributary entering on the east bank 1 2 TOWN Evaluation Record the town s in which the reach is located You may choose to enter this data in SGAT Step 10 If so the data will be transferred into the database with the other SGAT data upon completion of the SGAT evaluation 1 3 LATITUDE AND LONGITUDE SGAT Evaluation Latitude and longitude are north south and east west values respectively recorded as degrees minutes and seconds Record the latitude and longitude values for the upstream end of the reach and the down stream end of each reach Computer mapping tools such as GIS Maptec
157. series orthophotos Older aerial photos town tax maps and local knowledge may also indicate or confirm land cover changes In consideration of the time commitment necessary to conduct an accurate assessment of LcLu from his toric orthophotos that have not been digitized you may decide to focus only on those sub watersheds Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 39 April 2004 where visually significant changes have occurred i e noticeable increases or decreases in urban or crop land Since you will be looking at the 1970s orthophotos later in Step 6 4 to assess meander migration this may be the most efficient time to red flag those sub watersheds that merit an assessment of historic land cover land use Visually estimate dominant historic LcLu from maps aerial photos and orthopho tos or find the resources and or assistance to have the historic orthophotos for the sub watersheds of in terest digitized to complete the same GIS based analysis that can be done with digital layers for current LcLu Menu Wetlands Open water lakes ponds reservoirs streams and wetlands Forest Coniferous and or deciduous forest rural low density development Shrub Small trees shrubs and unmanaged grasses Field Agriculture pasture or hayfield orchard Crop Agriculture land tilled to grow crops Urban Moderate to high density residential commercial industrial roads Imp
158. siest and most accurate way to measure watershed size is to use GIS or other computer mapping tools but watershed size can also be determined manually with a planimeter Measure the primary water Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources 21 April 2004 shed and reach sub watershed areas in square miles on a 1 5 000 stream coverage overlain onto the 1 24 000 topographic maps See Appendix D for detailed in instructions on how to delineate watersheds Evaluation with SGAT SGAT will determine watershed size for each reach as well as the primary watershed size from manually digitized reach sub watershed GIS polygons 2 8 REFERENCE CHANNEL WIDTH SGAT Data sources Watershed size from Step 2 2 VT Hydraulic Regional Curves Appendix J e Any previously conducted surveys that include bankfull channel width Background Channel width as referred to in the phase 1 protocols means the width of the reference condition stream or river at bankfull flows measured across the channel at the flood height that occurs on an annual to bi ennial basis The channel width is generated for all reaches for the purpose of calculating confinement ratios and generating river corridors Evaluation At the Phase 1 stage of assessment you will have to rely on existing field data or a prediction of bankfull channel width calculated from the Vermont regional hydraulic geometry curve HGC HGCs for bank full discharge and chan
159. signed to the soil The overall percentage of highly and or potentially highly erodible soil values for the reach can be used to choose an appropriate value from the menu below For example if the value for highly erodible is 20 and the value for potentially highly erodible is 35 the overall per centage is 55 and the reach would be considered in the severe category for erodibility The erosion that is assigned in the NRCS Top 20 table is called the HELCLASS This value is for the erosion caused by overland flow on unvegetated soils and does not directly indicate the erodibility of the soils as it relates to the power of the stream working on them So be aware that a soil type that is listed as being not highly erodible may still erode when a stream is working against it Contact NRCS soil sci entists for more information about soil erodibility Menu Erodibility Percentage of reach which contains soils with HELCLASS highly erodible and or potentially highly erodible Slight 0 25 Moderate 26 50 Severe 51 75 Very Severe 76 100 Water Table Water Table information is usually listed in the Top 20 table or the Water Features table of NRCS soil surveys Enter the values under both the watershall and waterdeep categories Choices are in feet below ground surface ranging from 0 to gt 6 feet This information can be used to determine groundwater inputs to the stream Evaluation w
160. sily learned with some training If you are assembling a team of people to complete a Watershed Assessment it is very important to involve someone who has experience reading maps and ae rial orthophotos to assist you The involvement and technical assistance of specialists in the fields of ge ology aquatic ecology and fluvial geomorphology is also highly recommended Contact the DEC River Management Program the Vermont Fish and Wildlife Department or the Vermont Geological Survey about the availability of professionals in these fields and or to learn about opportunities and requirements for technical training to complete Phase 1 Assessments Reminder The right bank and left bank of a channel are defined looking downstream If you have any questions about the definitions of any terms please refer to the glossary in Appendix Q Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources 3 April 2004 Materials Needed You will need the following materials to complete the watershed assessment 2 copies of the topographic maps covering your watershed Orthophoto series two different time periods most recent and a series from at least 20 years ago Computer mapping program that can measure distances areas and latitude longitude OR Ruler and map wheel for distances grid overlay transparency or planimeter for watershed area and a latitude longitude ruler Soil surveys and surficial geologic maps Scientific calcu
161. so be from upland sources such as construction sites road washouts or valley side slope failures Note that in some situations equal sized alternating unvegetated point bars in a naturally high sediment yielding watershed may be a part of the reference or equilibrium channel condition Evaluation For large and medium sized rivers and streams large unvegetated bars are often visible on orthophotos If you are examining the orthophoto on the computer zoom in on the channel to observe gravel bars Note the presence of unvegetated mid channel point or delta bars and record the appropriate menu item on the data sheet These bars can also be noted in the field during the windshield survey Small streams Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 56 April 2004 particularly those in forested areas will be difficult to impossible to evaluate using orthophotos These streams will need to be assessed during the Step 7 windshield survey and Phase 2 or 3 assessments When evaluating bars in the Phase 1 assessment you will only note those bars that are largely unvege tated either devoid of vegetation or have only sparse pioneer vegetation occupying less than 25 percent of the surface area of the bar In the field during Phase 2 and Phase 3 Assessments you may observe bars that are well vegetated Menu Mid channel Flows evident on either side of mid channel sediment deposit Large unvegetated sed
162. stment Process or type of change that may be underway in the stream channel e g vertical lateral or channel planform adjustment processes due to natural causes or human activity that may result in a change to the valley floodplain and or channel and Reach Sensitivity of the valley floodplain and or channel to change due to natural causes and or human activity These assessment parameters are useful in evaluating the current and future conditions of gt stream and riparian habitat and gt erosion and flood hazards Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources April 2004 The Provisional Geomorphic Condition Evaluation is an appropriate tool for setting priorities and problem solving in a watershed context because it will not only tell you the proximity of adjusting reaches to one another but you will be able to ascertain how one reach may be affecting the condition of another If you or someone in your team does not have experience with predicting the channel ad justment processes and conditions that follow in response to channel and floodplain modifications you may want to put the Provisional Geomorphic Condition Evaluation Step 9 aside until you have spent more time in the field completing Phase 2 and or Phase 3 assessments If you opt for going to the field first it is highly recommended that you revise the provisional condition evaluations in the Phase 1 da tabase before setting priorities for prot
163. stream Evaluation Record the percentage of the reach length that has houses fill includ ing bridge and culvert fills parking lots or other development within the river corridor on either bank see Appendix E for river corridor de lineation Indicate whether the de velopment occurs on the right bank i Waihi te j w Nee a ig WwW 4 Se i AL Figure 6 2 Development within the river corridor and floodplain 2 Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 55 April 2004 RB or left bank LB as determined facing downstream Write None if you know there are no devel opments within the river corridor along the reach Retain a paper map or digital GIS shape file of river corridor development encroachments for later use in quality assurance documentation field verification and for display purposes Menu RB berms roads railroads or improved paths located within river corridor on right bank only LB berms roads railroads or improved paths located within river corridor on left bank only RB amp LB_ berms roads railroads or improved paths located within river corridor on both banks None No evidence of berms roads railroads or improved paths in river corridor Base your impact rating on the percent of the reach length that has been encroached upon by develop ments within the river corridor Impact Rating for river corridor development H High deve
164. stream is called windrow ing which may impact the morphology of the river For example many reaches of the White River and its tributaries in central Vermont were windrowed following the floods of the 1970 s Gravel was bermed up and gravel bars were removed from the river to improve the channel s capacity to move flood wa ters During the following decades some reaches experienced major damage caused by the changed mor phology of the river Damages included widening and bank erosion downcutting and significant changes in the cross sectional geometry of the river These reaches remain sensitive to change and ad justment due to these instream modifications especially during flood events NRCS 2001 Evaluation Check with the DEC stream alteration engineers NRCS staff and town road commissioners for docu mentation of historic channelization projects Some straightened reaches are easy to read off of topog raphic maps or orthophotos Figure 5 2 Measure and record the total reach length in feet and percent of reach length that has channel modifications Record the type of channel modification along the reach using the menu choices below Base your impact rating on the percent of the reach length that has been modified by channelization Retain a paper map or digital GIS shape file of channel modification loca tions for later use in quality assurance documentation field verification and for displaying the data Phase 1 Stream Geomorp
165. t over several iterations you should label all mainstem tributaries on the topographic maps up front to ensure that you have included all major tributaries in your numbering system This will avoid reach numbering errors in future assessment work preserving the capability to sort the watershed data hydrologically from downstream to upstream accord ing to the drainage pattern If you need assistance on where to start the numbering process contact the DEC River Management Program Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 12 April 2004 ge An at Bien hiz 02 Battenkill Surface Waters Li Reach Breaks 1 2 Milot i Le mE a Figure 1 4 Example of reach numbering system All reaches on tributary T1 would be preceded by M01 for example MO1T1 01 MO1T1 02 etc for graphical presentation it has been left off for this example 5 Watershed Orientation While many people are familiar with their watersheds they may not be looking at them in the context of a watershed assessment Getting out to see watershed streams by car or boat at the start of an assessment can help speed the process along by answering many questions that will arise later during the assessment The Watershed Orientation is useful in refining and verifying the first cut reach breaks Specifically it allows for a more detailed mapping of valley walls and field verification of valley confinement
166. tenua tion a floodplain is often the space or river corridor through which stream channels meander over time undergoing planform adjustment and thereby slope adjustment The availability of space for slope ad justment is critical to the stream in reaching equilibrium with the size and quantity of sediment produced in the watershed A stream cut off from its floodplain may have less room to meander and be forced into a higher gradient form If this higher gradient translates into stream power that can move even larger par ticles in the stream bed the channel may begin to degrade or incise cutting down into its streambed and initiating the channel evolution process see Appendix C Evaluation Similar to the evaluation of channel modifications in Step 5 in this step you will evaluate floodplain modifications and planform changes that have occurred over time in order to help predict whether reaches are in adjustment The floodplain modification and planform change parameters examined in Step 6 will be very useful in predicting the condition current adjustment process and sensitivity of the stream reaches in the watershed Data Sheet 6 Floodplain Modifications And Planform Changes 6 1 BERMS amp ROADS Data Sources e USGS 1 24 000 topographic maps digital or hard copy 1990 series 1 5000 Orthophotos digital or hard copy Berms NRCS Flood Damage Remediation Emergency Watershed Protection EWP Reports Berms DEC St
167. these on the topo map with the letters GC Most grade controls are identified in the field so make sure to note them during the watershed orientation Step 1 and during the windshield survey Step 7 Menu Dam Constructed dam or weir Ledge Bedrock ledge or waterfall Multiple Multiple grade controls along the reach None No grade controls on reach No Info Unknown if grade controls present Data Entry Use the check box in the database to indicate whether the grade controls were identified in the reach dur ing windshield surveys or watershed orientation or Phase 2 Phase 3 assessments Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources ZIE April 2004 Figure 3 3 Natural ledge grade control left and dam grade control right 3 3 GEOLOGIC MATERIALS SGAT Data Sources Vermont Geological Survey VGS surface geologic maps Natural Resource Conservation Service NRCS soil surveys e NRCS Top 20 soils tables available at http www vt nrcs usda gov Soils so_databases htmlT Background Stream equilibrium is in large part a function of the size and quantity of sediment which is transported by the stream i e stream type is dictated by sediment regime Insights to stream type and sediment regime may be made by evaluating the surficial geologic materials available for transport in the water shed and river corridor The Soil Surveys of the NRCS con tain a wealth of infor
168. tics of streams Two of the most commonly used systems are those of Rosgen 1996 and Montgomery Buffington 1997 Table 2 2 below combines sev eral features of these systems The reference stream type describes the natural central tendency of chan nel form and process that would exist in the absence of human related changes to the channel floodplain and or watershed Given the long history of stream channelization and of human related changes to the Vermont landscape the reference stream type is based largely on characteristics of the valley geology and climate of the stream lineation of stream types at this broad level leads to data organization and the ability to develop a set of analysis priorities for the next more detailed level of stream classification in ventory Rosgen 1996 The Phase 1 database serves as a repository for reference stream type information and other provisional data until Phase 2 and Phase 3 field assessments can be conducted Remote sensing data in the Phase 1 database provide a powerful tool for guiding watershed level decisions especially when conducting field assessments on every reach in the watershed is impractical in the near term As the Phase 1 database be comes populated by reference stream type evaluations and impact ratings refined by field data it will be come an even more rigorous guidance tool for watershed planners and managers In a Phase 1 assessment reference stream types are defin
169. tions that have occurred over time These pa rameters will be useful in predicting the condition current adjustment process and sensitivity of the stream reaches in your watershed Data Sheet 5 Instream Channel Modifications 5 1 FLOW REGULATION AND WATER WITHDRAWALS Data Sources e USGS 1 24 000 topographic maps hard copy or digital Town Records The following DEC Programs Water Quality Division Hydrology Section 241 3770 dams bypasses and snow making Water Supply Division 241 3400 public water supply withdrawals Facilities Engineering Dam Safety Section 241 3454 Background Structures that completely span a channel such as dams can significantly alter the quantity and duration of water and sediment runoff and may cause a stream to undergo both vertical and lateral channel adjust ment processes Depending on the timing and magnitude of flow regulation and the stream types and conditions above and below the facility these adjustment processes may occur annually or they may oc cur quickly when the flow alteration first occurs and then slow as the stream adjusts to new flow and sediment regimes Impoundments and water withdrawals can impact instream habitat and biota especially during naturally low flow periods that typically occur in Vermont in August September and February In addition to Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 45 April 2004 channel adj
170. tos offer the most accurate location of channel meanders Two rules to remember when drawing the me ander belt width are 1 do not cross the toe of either valley wall generally and 2 follow the direction of the valley i e draw the parallel lines that represent the belt width roughly parallel to the valley walls Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 60 April 2004 After establishing the two parallel lines containing the belt width measure and record the average to the nearest foot of at least three belt widths in the reach Divide the average belt width B by the channel width Wbkf to calculate meander width ratio MWR Figure 6 5 Retain a paper map or digital GIS shape file of locations used for belt width measurements for later use in quality assurance documentation field verification and for displaying the data Bl MWR B Wor Figure 6 5 Example of measuring average belt width in a broad unconfined valley In this example the belt width is the average of B1 and B2 values Appendix H provides more background information on meander width ratios and several examples of belt width measurements using Vermont orthophotos Impact Rating for meander width ratio H High calculated MWR is lt 3 or gt 10 L Low calculated MWR is 3 and lt 5 or gt 8 and 10 NS Not Significant calculated MWR is 5 and 8 N A Not applicable for certain stream types where MWR entered as 0
171. tream types C and E may be more sensi tive to adjustment than steeper sloped streams in confined glacial till valley settings stream types A and B e Sand and gravel bed streams are more sensitive than boulder and cobble bed streams especially in steeper valley slope settings Stream with no grade controls and little or no woody buffers are more sensitive than streams with numerous grade controls and woody riparian buffers Phase 1 Stream Geomorphic Assessment Vermont Agency of Natural Resources 74 April 2004 Streams with large peak discharges of storm water and sediment are more sensitive than streams with moderate to low peak discharges For example look for streams evaluated in Step 4 as hav ing high percentages of urban and cropland in the watershed river corridor and buffer zone Stream reaches with very unstable channels immediately upstream or downstream may be more sensitive than streams with stable channels upstream and downstream and Streams that are already assessed as in adjustment and or as having changed stream type fair or poor condition may be very sensitive to further impact and adjustment Menu Stream type and condition not very sensitive to change future reach and watershed Low a ie modifications are unlikely or not subject to head cutting from downstream reaches Stream type and condition may be sensitive to change future reach and watershed Moderate P La l
172. types seem true to what you see on the map Some maps in VT are in meters and it is easy to take the elevations in meters while the lengths are collected in feet If you see what appears to be a steep narrow valley and the slopes in steps 2 3 and 2 5 are shallow indicating a C stream type be sure that the data was collected in the same units Stream types may have to be adjusted accordingly if there are changes made to slope values gt Review the confinement types Where there is a steep narrow looking valley V shaped on the map check to see what confinement type chosen was Where an attempt was made to measure the valley width in these steeper valleys a large confinement ratio may be derived giving a broad or very broad confinement type If broad or very broad was chosen does it seem reasonable Guidance in the handbook suggest choosing a narrow to confined valley type for these V shaped valleys pending field verification gt InStep 3 you can check for alluvial fan and valley side slopes to see that the chosen characteristic seems reasonable Remember that the alluvial fan is only counted on the reach itself not on tributaries entering the reach Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources 78 April 2004 2 Document information for the reach itself gt If there are parameters where information was evaluated but a no info was chosen as the impact score
173. ustments that may affect the structure of instream habitat additional withdrawal of water can expose streambed substrates effectively reducing the amount of habitat area available for aquatic organ isms In high gradient streams cobble and gravel substrates in riffles are exposed in low gradient streams the decrease in water level exposes logs and snags and lowers the water away from near bank cover thereby reducing available habitat Impoundment of stream flow can also warm waters substan tially due to longer periods of and greater surface area of solar exposure making streams less habitable for many aquatic organisms especially for cold water fish species such as Brook Trout Salvelinus fon tinalis Evaluation Most large dams are shown on the USGS topographic maps as a short black line crossing the stream blue line This can help you locate these large dams but you will still need to contact other sources to find out how they are operated Consult with DEC Water Quality and Water Supply programs town records utilities landowners and businesses that may be able to provide information on projects and facilities that regulate the flow or withdraw water from the stream reach Choose from the menu list to describe the type of flow regulations present in the reach If there is more than one type of regulation present choose the type that influences the reach the most Menu Drinking Public water supply withdrawa
174. valley width in feet It may be hard to get a map based measurement in narrow V shaped valleys because there is not enough topographic f ta fot detail to show the true valley bottom Use HS yo valley slope as a guide Where it is diffi IN j i TF wl K on Pa VV 4 cult to get a sense for the width of the val MESS peers e ley bottom and the valley slope is greater Figure 2 3 Example of valley width on a topographic map than 1 5 label the valley as confined Phase 1 Stream Geomorphic Assessment VT Agency of Natural Resources 23 April 2004 valley types 1 NC or 1 SC Table 2 1 pending field verification Often in these cases valley width is equal to or only slightly greater than channel width but do not be surprised if this does not always hold true Valley floors that appear narrow on a 1 24 000 topo map with 20 foot contour intervals may actu ally contain a floodplain that is broad in comparison to the small stream that is flowing there Evaluation with SGAT SGAT will generate valley width for those reaches where you have delineated valley walls Otherwise you will need to measure valley width by following the above procedure SGAT Step 10 provides the opportunity to enter data for reaches where you manually measured valley width Data Entry Use the check boxes in the database to indicate whether the natural valley width for the reach was deter mined during windshield surveys or Phas

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