Estimation of Annual River Pollutant Loads with Flux32
Contents
1. STEP 6 Name flow input file according to following naming convention Example River Discharge 75 09 xls Note If updating an existing Flux32 input file update the Notes page and resave file in appropriate file folder with new file name appropriate for the most recent data added i e River Discharge 75 10 xls Do not alter existing files as they will be used to recreate loads if questions arise in future MCES internal file structure for the storage of Flux32 files is outlined in the Annual WQ Assessment SOP File Location NATRES Assessments Documents SOP SOP_WaterQuality Assessment V1 doc Action 2 Create Flux32 Input File Water Quality Fi STEP 7 Download verified water quality data from the Water Quality Database Each site s data report should include a date sample identification number and a water quality concentration per constituent per sample STEP 8 To avoid calculation error in Flux32 make sure there is only one sample per date o For two or more grab samples per date average concentration STEP 9 Create an Excel spreadsheet with separate worksheets for each site location as well as a worksheet for notes related to changes and updates made to each dataset The excel file will serve as the Flux32 Water Quality Input File Notes MN Jordan SCrx_ Stillwtr M5 _L amp D3 MS Anoka STEP 10 Each site specific Excel worksheet should use the following format or append new data to existing input file o Cell2. lt 0 3 Residual R amp Slope 0 Method 6 Methods 3 5 Input Files Into Flux32 Flux3 assessment Water Quality Input Method 6 Regression 3 Discharge cfs Flux Units metric tonnes y Examine distribution of samples vs daily flows Do samples capture peaks Cone Units PPM mg L Mass Units metric tonnes Volume Units million tts Examine relationship between Q C log A strong relationship exists if R2 gt 0 757 Plot Residuals vs Flow Date Month Improve Diagnostic oS j E Are there breaks in Season Statistics by Stratification Stratification Plot Residuals vs Flow Date and Month Optimum Residual Stats season or discharge If possible improve Slope 0 residuals by stratification J f Pm R 0 Choose Appropriate Stratification Check CN Validate Load Type based on Acceptable CV should be 3 0 3 Caleulation Statistical Values Date Stratification Calculate Load Check for Residual Outliers Are there are outlier samples which P lt 0 05 If yes is there a valid reason to eliminate the sample Statistics can t be met regardless of the stratification scheme or Method Load can not be calculated Note Discharge Stratification Examine Flow Weighted Concentrations from the Loading f oc Ve ae E x 1 ress lts P heg 4 i Summary possibile reason in results worksheet i e p E unexplained outlier insufficient d
3. monthly calendar Use 1 Day as Maximum Gap for Interpolation Calculate Series Calendar Year 1 Day as Maximum Gap for Interpolation Calculate Series Monthly 1 Day as Maximum Gap for Interpolation Calculate Series Daily 1 Day as Maximum Gap for Interpolation Enter Maximum Gap Days for Interpolation of Residuals i DONE CANCEL STEP 32 Save output file using the following naming convention Sitenameabbreviation parameter year txt Example MNJORD NO3 2009 txt STEP 33 Load values and statistics are manually extracted and summarized within a historic river loads worksheet The location of the MCES River Loads dataset is NATRES Assessments WQ Load Calculations 2009 Output _Files Rivers 2009 River WQ L oad Dataset xlsx If additional load data is added to the 2009 River WQ Load Dataset xlsx the user should update the Notes worksheet Information provided within the 2009 River WQ Load Dataset xlsx includes O 000000000 0 Site Parameter Analysis period Stratification scheme and divisions Calculation method Samples used excluded Observed flow volume Flux modeled mass and concentration Flux interpolated mass and concentration CV Coefficient of Variation Upper and lower limits of 95 confidence interval Step 34 15 W STEP 34 The upper and lower confidence limits of the 95 confidence interval should be calculated and reported within the MCES River Loads data
4. Al has no effect on Flux and should contain site description and any other relevant information o Cell B1 should define the concentration units used i e mg L o Cell Cl defines the sample flow units but should be left blank for river load calculations o Format each site worksheet as follows Site Quality MN_Jordan aan Format a a N Te Tss EE STATION DATE Field_Data_ID TP MI39 4 01 01 80 345678 0 105 MI39 4 01 14 80 356780 0 255 1549 STEP 11 If modifications are made to the water quality dataset the changes should be reflected within the _ Notes worksheet The format of the Notes worksheet is as follows Notes ee Format DATE Th DATE NOTE DOWNLOAD DATA FILENAME AUTHOR 3 05 26 09 Added 2008 data 05 13 09 River WQ_7608 xls KMI 05 28 10 Added 2009 data 05 20 10 River WQ 76 09 xls lv STEP 12 Name flow input file according to following naming convention Example River WQ 76 09 xls Note If updating an existing Flux32 input file update the Notes page and resave file in appropriate file folder with new file name appropriate for the most recent data added i e River WQ 75 10 xls Do not alter existing files as they will be used to recreate loads if questions arise in future MCES internal file structure for the storage of Flux32 files is outlined in the Annual WQ Assessment SOP File Location NATRES Assessments Documents SOP SOP_WaterQuality Assessment V1 doc Action 3 Load Flux3
5. Attachment B for complete documentation o Mississippi River at Anoka There is no continuous average daily flow monitoring at the location Mississippi River at Anoka MN where MCES water quality samples are collected As a result the discharge is estimated by subtracting the Rum River and Elm Creek average daily discharge from the USGS monitoring site approximately 7 miles downstream of Anoka and the MCES site Please refer to Attachment c for complete documentation kW STEP 4 If not already developed create an Excel spreadsheet with separate worksheets for each site location as well as a worksheet for notes related to changes and updates made to each dataset The excel file will serve as the Flux32 Discharge Input File Notes MN_Jordan SCrx_Stliwvtr MS Prescott MS Anoka STEP 5 Each Excel worksheet should use the following format or append new data to existing input file and update notes page The notes worksheet should be updated as new data is added each year o Cell Al has no effect on Flux and should contain site description and any other relevant information o Cell B1 should define the flow units used i e ft3 sec o Site Discharge MN_JORDAN Worksheet Format i ees es e La I sitedeseripion ose iY 2 pate mow QUALIFIER 3 ome fo o a owe fis ie o Notes Worksheet Format odla ee es Kn P l Sitedescription fT DATE NOTE AUTHOR 05 26 09 Added 2008 data KMJ 05 28 10 Added 2009 data ATF J
6. average flow and grab sample chemistries using the U S Army Corps of Engineers software Flux32 Due to differences in input data processing and load estimation methodology a separate SOP exists for estimating annual loads for monitoring stations located on the tributary streams within the Twin Cities Metropolitan Area Since flow in the four major rivers responds relatively slowly to precipitation events MCES and MPCA Minnesota Pollution Control Agency staff have determined based on the MCES sampling frequency that using a one year record of average daily flow and grab sample water chemistry data is adequate to estimate annual loads for the major rivers with acceptable uncertainty The application of a one year dataset to define an annual river load rather than multiple years is acceptable since river events are typically defined as a multi day record 3 days or greater The subtle nature of the river system hydrograph along with consistent frequency of monitoring allows for a strong statistical relationship when using regressions within Flux In comparison the streams possess relatively flashy event hydrographs at times defining 2 days or less requiring the stream load estimates to rely on a 3 year dataset MCES River Load Estimation SOP Page 1 of 16 Annual load estimates for the rivers will be used within the Metropolitan Council benchmark report annual water quality summary reports special studies and shared with external stakeho
7. ensure proper loading and assess potential stratification schemes Confirm that flow data are complete without breaks and that number of samples indicated seems appropriate W STEP 21 Set Data filter screen to include only data period of interest o Data Screen filter data Apply Date amp Value screens Sample Date Range For river sites one calendar year of data are used to develop regression equations used in estimating loads The max date should be set to the last day of the year of interest 12 31 2009 when estimating 2009 loads The min date should be set to the first day of year for estimating 2009 loads the min date would be 01 01 2009 o Data Screen filter data Apply Date amp Value screens Flow Date Range For river sites one calendar year of data are used The max date should be set to the last day of the year of interest eg 12 31 2009 when estimating 2009 loads The min date should be set to the first day of year for estimating 2009 loads the min date would be 01 01 2009 Note Once dates are changed using data screen do not simply change the dates again to re filter data as an error occurs and data will not be loaded properly To reset dates Data Screen filter data Apply Date amp Value screens Reset and then repeat date filter process described above c ox Accept Values Between amp including MMDDNYYY MMOD YY Seasonal Range TT MMDD Wraps Ac
8. site_no 05341500 amp amp o Mississippi River at Prescott WI USGS 05344500 http waterdata usgs gov nwis inventory site_no 05344500 amp amp O Mississippi River at Lock amp Dam 3 Site used for discharge adjustment http www mvp wc usace army mil projects Lock3 shtml W STEP 2 Ensure that the flow dataset is complete for the period of interest with no missing data As outlined in STEP 3 there are two sites that typically have long periods of missing record and therefore need additional modification W STEP 3 Modification of Average Daily Discharge Flow Record for Three Sites o Mississippi River at Prescott Average daily discharge from the USGS Mississippi River at Prescott WI station is measured on a water year basis Oct Sept As a result when calculating annual loads there is three months of missing flow data for the previous year Rather than use a regression to estimate the flow it was determined that the USACE average daily discharge at Lock and Dam 3 was appropriate to fill in the missing data Please refer to Attachment A for complete documentation o St Croix River at Stillwater There is no continuous average daily flow monitoring at the location St Croix River at Stillwater MN where MCES water quality samples are collected As a result the discharge is estimated through the summation of the upstream St Croix River at St Croix Falls and an upstream tributary Apple River at Somerset Please refer to
9. there is some variability between the flow weighted concentrations of Methods 3 5 but all indicators suggest an appropriate dataset proceed will load calculation and make note of variability STEP 28 Once diagnostics are evaluated and optimized calculate final loads and create output file as defined in Action 5 Action 5 Create Output File STEP 29 Open text editor like Notepad or Notetab Light STEP 30 Enter introductory information as follows Format Example Site name parameter year of interest Minnesota River at Jordan Nitrate 2009 Date of analysis and analyst name 04 15 2010 Adam Freihoefer Version of Flux32 Flux32 Version 1 1 2 3 10 09 Input files River Discharge 75 09 xls River WQ 75 09 xls Stratification breaks Seasonal 4 Strata 01 01 04 07 07 26 10 01 Outliers deleted No Outliers Deleted Note While flow residuals look good monthly Notes residuals are biased sloped Minnesotan River at Jordan Nitrate 2009 Model by Adam Freihoefer 04 15 2010 Flux32 Output Model Version Date 03 23 10 River Discharge 75 _ 09 xls River Wo 75 09 x1s Stratification Seasonal 4 Strata 01 01 04 07 O07726 10 01 Wo Outliers Deleted Notes Example of Required Flux32 Output Header Per Each Load Output 14 WI STEP 31 Once above information has been added then cut and paste the following into the text file in this order o Calculate Loads o To calculate time series loads daily
10. 2 Input Files for New Project W STEP 13 Open Flux32 executable 2 If starting a New Project Data Read New Sample and Flow Data New Stratification If opening an existing project Session Resumed Saved Session FSS File W STEP 14 After selecting New Stratification Flux32 will prompt the user to locate the file directory of the discharge River Discharge 75 09 xls and water quality samples River WQ 76 09 xls lv STEP 15 Flux32 will first read in the discharge worksheet If the daily flow file contains multiple worksheets the user must indicate what worksheet i e monitoring site is going to be used and column identifier that the flow data is located in Select One Sheet For Input Pick The DAILY FLOW Field From The List QUALIFIER lv STEP 16 Flux32 will then read the water quality worksheet Similar to the discharge input if the water quality file contains multiple worksheets Flux32 will prompt user to select the worksheet that contains the appropriate site information 1 e monitoring site to be used Flux32 will next prompt user to select SAMPLE FLOW Field from a list of fields For river load estimation the user should select the LOOKUP Use Daily Flow since the MCES water quality samples do not have an associated sample flow MCES typically uses the daily average flow to represent the sample flow when calculating major river loads Most major river samples are collected as grab samples
11. 8 J LOAD ESTIMATES FOR NOS Z1 Flv Wated EAD Cae K Method Mass ikg 2 Fluxikg yi Flux Variance Conc mg L d gew 3 l Average Load 15071668 1 5081939E7 l 8 7S557E12 3 83 l 0 156 z Flv Wghted Conc L3754739 1 376416E7 82622E12 3 445 O 1 21 l 3 Flw Wghted IJC 13470959 1_348019E7 l 2 73005El1 Z 3 42 l O 12 26 i 4 C Q Begl 12368556 j L 239704E7 6 amp 06934E1z2 3 14 I 0 1987 E Cy O Beg Varid7 1Z 192524 1 220127E7 l 7 10141E1z2 3 1 l O 2 164 l 6 C O Eeg3idailyi 34689662 S 471342E7 1_13774E14 5 51 O 3073 I 8 Time Series 14269262 V 1 427304E7 y NA 3 62 Nra rs WI STEP 24 Examine initial qualitative graph and quantitative statistics diagnostics o Plot Residuals vs Flow Show Stats Plot Residuals vs Date gt Show Stats Plot Residuals vs Month Show Stats When plotting Note Input data and associated loads for a river may be influenced by flow and by date season in which case the flow residual plot may look acceptable no slope high slope significance low R while the date or month residual plots may be sloped indicating a date or seasonal bias Flux32 does not include both date and flow relationships in the load estimates however the USGS load estimation tool LOADEST does have that capability With Flux32 the user must choose to either minimize flow residuals or minimize date seasonal residuals using stratification O O OD 11 b STEP 25 Upon exa
12. Metropolitan Council Environmental Quality Assurance EQA Environmental Services Standard Operating Procedure Standard Operating Procedure Estimation of Annual River Pollutant Loads with Flux32 1 2 Updated 12 01 2010 12 09 2011 1 20 2012 Author s Karen Jensen Adam Frethoefer To calculate the annual pollutant loads for Twin Cities Metropolitan Area rivers using Flux32 software and water quality and flow data collected by the Metropolitan Council Environmental Services MCES EQA Environmental Monitoring and Assessment Unit or other project partners USGS Flux32 software most recent version Download at ftp ftp usace army mil pub erdc EL Simple_ Tools FLUX_ Updates Materials Daily average flows continuous record of measured and estimated daily flows Grab sample water quality concentrations Manual IR W 96 2 pdf Simplified Procedures for Eutrophication Assessment and Prediction User Manual William W Walker Instruction Report W 96 2 September 1996 Updated April 1999 U S Army Corps of References Engineers USACE SOP Flux32 Stream Load Estimates V1 doc MCES Steps for Flux Analysis _draft_200307 doc MPCA FLUX32 Process Checklist doc Summary Contents TS Systematic Operations Attachments A B Summary Procedure Description This SOP outlines the MCES methodology for estimating annual pollutant loads of three major rivers Mississippi Minnesota and St Croix from monitored daily
13. STEP 26 Check diagnostic plots and statistics Once strata breaks are set go through following process to check diagnostic plots and statistics Table 2 outlines diagnostic tests and goals Table 2 Flux32 Diagnostics for Load Calculation Acceptability Flux32 Diagnostic Plot or Statistic Plot Residuals vs Flow vs Date vs Month Calculate Loads Calculate Compare Sample Flow with Total Flow Distribution List Residuals Outliers List Jackknife Table List Breakdown by Stratum and Optimum Sampling Examine residual plots for bias Click Show Stats on plot Often bias can be eliminated for Flow or Date but not both Creates summary table of load by method also gives C V by method Provides a variety of statistics comparing sample flow with total flow distribution Provides lists of statistical outliers P lt 0 050 Jackknife procedure systematically deletes individual samples and recalculates load without that sample then presents change in load estimate Can provide information about optimizing sample collection during future efforts No slope slope 0 Minimize R R 0 Maximize Slope Significance 1 Flow weighted concentration estimate for Method 6 should be within 20 of Methods 3 5 C V range 0 0 1 Good 0 1 0 2 Fair gt 0 2 Poor gt 0 3 Unacceptable Provides information about distribution that may help with data interpre
14. and the major river flows change relatively slowly thus use of daily average flow as an approximation of sample flow is appropriate Note This differs from stream load estimation as tributary streams are typically flashy and therefore daily average flow is not a good surrogate for event flow The tributary streams have either a grab or composite flow associated with sample chemistry and daily average flows are used only to estimate loads for those days without a sample flow Ssmerjiestforiipue ama Pick SAMPLE FLOW Feld Select One Sheet For Input Pick The SAMPLE FLOW Field From The List Pick The FLUX CONSTITUENT Field From The List MN_JORDAN SCRX_STLLWTR MS_PRESCOTT MS_ANOKA RUM_STFRANCIS eA 5 D gt Cance W STEP 17 Flux32 will next prompt user to select the FLUX CONSTITUENT Field from a list of fields Select field name of parameter to be estimated W STEP 18 Flux32 will then prompt user to complete the following o Enter Modify Site Name Enter appropriate site name and location o Confirm input data Examine the page to make sure number of daily flows and number of samples seems appropriate o Confirm appropriate values for unit conversion Ensure the conversion factors are correct 0 894 if using cfs 1 000 if using mg l Use dropdown menus to change values if necessary Note If Flux32 detects duplicate samples open the water quality input file and manually delete duplicates as d
15. ataset Is the Method 6 concentration alc uwen INSuUJJICI j within 20 of Method 3 5 concentrations Export Flux32 Results Method 6 Annual Monthly and Daily Loads Statistics to text file Export Flux32 Results to Load Summary Worksheet Excel File Save Flux3 Session File Complete Methods 3 5 Annual Loads Statistics to textfile Are Methods 3 5 within oe Change to Regression 20 of each other Method 3 5 af IESE Indicates cited process step in associated No No Load Caleulated MCES Flux32 River Load SOP document Discrepancy between load estimations methods is too large File Name MCES River Flux32 Users Diagram pptx Note in Load Summary Worksheet Tar aaaiae CAMARIM pp Updated 9 17 2010 ATF Figure 1 MCES Flux32 SOP Overview MCES River Load Estimation SOP Page 3 of 16 Action 1 Create Flux32 Input File Daily Average Flow W STEP 1 Download the average daily flow from the USGS or USACE Website o Minnesota River at Jordan USGS 05330000 http waterdata usgs gov nwis inventory site_no 05330000 amp amp o Mississippi River at Anoka USGS 05288500 http waterdata usgs gov nwis inventory site_no 05288500 amp amp o St Croix River at St Croix Falls USGS 05340500 http waterdata usgs gov nwis inventory site_no 05288500 amp amp o Apple River at Somerset WI USGS 05341500 site used for discharge adjustment http waterdata usgs gov nwis inventory
16. escribed previously in this SOP Reload data into Flux32 Do not use the Flux32 prompts to delete duplicate samples Action 4 Estimate Loads with Flux32 W STEP 19 Define Initial Settings o Select Method 6 Method 6 Regression 3 Daily log c log q adj Note Method 6 is the preferred calculation method as it designed for use with the time series function which will be used later in this SOP to save data output for yearly monthly and daily time steps If a load is unable to be calculated using Method 6 the user may use an alternate method and refrain from citing sub annual time series information A complete explanation of the Method 6 departure criteria is outlined in Step 27 LOU Load Estimating a Session Data Edit Calculate Plo Untitled Session Sample File River Vl fa oO Sample Count 956 121 Valuef Start Date 0524 1979 End Date 1218 2009 Flux Variable NOs SOANE t Method List Utilities Title Help Quit 1 verage Load 2 Flow Weighted Conc 31IC Ratio Flow Weight Adjustrnt 4 Regression 1 C O Slope F 5 Regression 2 Variance Adjusted e 6 Regression 3 Daily logCflag Adj Di Help o Select Units Utilities Preferences Change e Confirm discharge units are in cfs and concentration units are in mg L The Flux Units and Mass Units can be set to whatever the user would like the output to be in Ibs kg or metric tonnes W STEP 20 Examine entire dataset to
17. lders Basic steps for estimation of annual loads include Figure 1 e Creation of two Flux32 input files per site average daily flow and water quality Table 1 e The estimation of loads using Flux32 software This effort typically requires adjusting flow or seasonal stratification breaks to reduce the coefficient of variance C V to 0 3 in an effort to reduce the slope in residual plots and ensure that the methods produce similar results e Creation of output text files in specified format to document Flux32 results e Transfer the results to master database of river load results Table 1 Historic MCES and USGS Metropolitan Area River Sites River Name and Mile of Discharge Discharge Water Quality Water Quality Monitoring Station Owner Monitoring Record Owner Monitoring Record Minnesota River at Jordan USGS 05330000 1934 Present MCES MN39 4 1979 Present Mississippi River at Anoka USGS 05288500 1931 Present MCES UM871 6 1976 Present MCES River Load Estimation SOP Page 2 of 16 MCES Flux32 SOP Overview for River Load Calculations MSSP Input Files SOP Version 1 0 44Council Flux32 Average Daily Discharge Input f N Set Date Filter For rivers Use 1 calendar year Examine data for proper loading and initial Load Discharge and WQ Calculate Initial Loads Single Strata Define Flux Settings Examine Di tic Stats Units Regression 6 xamine Diagnostic stats CV
18. mining the initial load results using a single stratum the user has the option of assigning multiple strata based on discharge or seasonal date The objective is to reduce the C V and minimize residual slopes o Stratify data Data Stratify On Flow On Hydrograph On Season On Date o On Flow Stratification Typically relies on two strata split at Qmean or three strata split at 2 Qmean and split at 2x Qmean Upon choosing one of the flow strata the user can then manually edit the strata boundaries through numeric or graphical means If the user would prefer to manually enter all of the strata breaks use Data Stratify On Flow Other o On Season Stratification Stratification breaks often correlate with winter mid October January spring February mid May summer mid May mid August and fall mid August mid October Examining the graphical interface will assist the user in appropriately identifying strata breaks Assign Seasonal Sirata A E File Format Axis View Help Observations by Month a004 NOs img Daily Discharge CFS B 00 4 NOS mg L t Co Co Daily Discharge CFS 2 00 Add Stratum 0 00 o On Date Stratification Using the date function allows the user to break up strata while viewing the hydrograph Similar to the season stratification it is recommended that the user identify and define strata breaks with the graphical interface 12 b
19. ross Year STEP 22 Examine filtered dataset to ensure proper loading and assess potential stratification schemes Make sure flow data is complete without breaks and that number of samples indicated seems appropriate Examine plots for concentration vs flow or concentration vs season relationships Look for logical breaks in relationship where stratification breaks could be made Plot Conc vs Flow linear o Plot Conc vs Flow log o Plot Conc vs Date o Plot Conc vs Month O FLUX Load Estimating Sot tware Plot Method List Utilities Title Help Quit Session Data Edit Calculate i YS Flow Untitled Session Load vs Date Mas vs Month Sample File River Wa Flow F Estimated j ost jin SEEN a Histogram of Observe serene ee SEANA M _ i E _ Barchart Flow Wightd Est by Stratum 4 Start Date 05 241 379 me ee BarChart Fla Wighted Est by Method End Date 1271812009 7 End Date 1231 2009 Mis Flux Variable NO3 Fow Frequency Distrib t Flow Variable Daily Discharge l Flow Exceedance Duration Curves P Mean Flow 6457 7 CFS aad Duration Curve Mean Flow 9893 3 CFS Dates and Means Ignore EXCLUDev Lata o Verify the distribution of samples versus daily flows to ensure that the samples capture the peaks This information can be obtained using the Quick Plot tool on the main Fiar Gos x Dele o While there are no specific cri
20. set in conjunction with the other parameters indicated within Step 33 The method to calculate the limits 1s cited within the Flux user s manual entitled Simplified Procedures for Eutrophication Assessment and Prediction User Manual William Walker 1999 as follows Y e2 0 2 CV Lower Limit value Upper Limit value Ym el where Y 1s the predicted mean value and CV is the error mean coefficient of variation W STEP 35 Save Flux32 Session File using similar naming scheme as used in Step 32 O Session gt Save This Session Save output file using the following naming convention Sitenameabbreviation parameter year txt Example MNJORD NO3 2009 FSS 16
21. tation Outliers should only be deleted with some evidence of problem with sample Deletion of outliers can greatly affect load estimates If outlier is deleted be sure to note in output text file Look through table and identify individual samples that greatly influence load estimate May add in interpretation or aid in elimination of outliers Can aid in data interpretation 13 STEP 27 If diagnostics are acceptable based on calculation method and statistical relationships proceed to Step 28 If diagnostics are unacceptable first attempt to adjust stratification breaks or change stratification scheme for example change from flow stratification to seasonal stratification Evaluate outliers and jackknife to identify aberrant samples Outliers should be deleted cautiously and only with reason o Ifthe Method 6 flow weighted concentration is greater than 20 then the use of Method 6 should be abandoned for an alternative methods Methods 3 5 If using Methods 3 5 it is advised not to use the time series function and therefore the user will only be able to cite annual modeled loads rather than monthly or daily o If the none of the methods produce a statistically significant load C V lt 0 3 and indicators exist such as weak representation of samples to the daily flow regime and poor residual statistics regardless of stratification scheme you may not be able to calculate a load for the specified calendar year If
22. teria for appropriate flow vs concentration or the distribution of samples to daily flows weak relationships can hinder the users ability to calculate loads and can be used to justify the inability to calculate a load Step 27 10 WI STEP 23 Calculate initial loads which relies on single stratum o Calculate Loads o Examine Flow and Load Summary output In particular Do the daily flow statistics agree with the dates selected in the data filtering process 1 Is the Flux kg y similar between the various statistical methods 1 6 2 Is the Method 6 C V lt 0 2 How do the Method 6 results compare to the other methods 3 The inability to meet the following criteria does not necessarily mean a load cannot be calculated however additional modifications to the data as outlined in subsequent steps i e stratification method change may be needed File Edit Format Untitled Session FLOW AND LOAD SUMMARIES FOR NOS Method C Q Beg3tdaily 63 DISTRIBUTION OF SAMPLES VS DAILY FLOWS Daily Flow Smpl Flow Woz FLUX SLOPE Stratum Flows Smpls Ewmts Vol CFS CFS mo L tkg wi LalfLgt E p CO Overall 365 40 40 100 0 4410 806 4833 11Z 3034 4 34713422 1 144 0 44 0 000d DAILY FLOW STATISTICS Daily Flow Duration 365 Days 0 999 Years Taily Mean Flow Rate 4410 81 CFS Daily Total Flow Volume 3939 24 Heqa m7 aily Flow Date Range 2009_01 01 to 2009 12 31 1 Samples Date Range L 2009 01 09 to 2009 12 1
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