Collaborative Watershed Modeling using the Internet Modeling
Contents
1. Because each Child project is checked every time TR20 is run for the Parent project the most up to date hydrographs are always included in the Parent project s model The TR20 command used to add a hydrograph into the model is the ADDHYD statement This is fairly straightforward when all of the hydrographs are stored locally meaning on a hard drive in the computer or on a network Collaboration on Large Projects a When a project can not be done on one computer or on one network the internet is sometimes used to draw the various an components together The internet or World Wide Web is being used by Civil Engineers in government private practice and academia to collaborate on building projects site developments infrastructure and a wide variety of projects in general When using the internet in this way the general schematic of the process is that of ia a wagon wheel with the project at the center and input from various wo professionals who can be geographically separated as the spokes of Normal collaboration on a the wheel Collaboration among these professionals can be thought of Jgrge project as the rim of the wheel This works well when all the participants are each working on a different part of the same project and have the ability to work somewhat independently of the others For example after the building footprint is determined design of the mechanical electrical and plumbing work can begin without everyone waiting for2. HMS Hydrologic Modeling System U S Army Corp of Engineers This successor to HEC 1 allows the user to add upstream modeling results by using a Source element From the HEC HMS User s Manual Version 2 1 p 43 The source can be used to represent boundary conditions to the basin model such as contributing area modeled in a separate basin model SWMM Storm Water Management Model U S EPA The SWMM Version 4 User s Manual on page 44 describes the use of a Combine Block as follows The output of any other model can also be combined or collated with SWMM files by the Combine Block if the model output is in SWMM interface format C A Proposal for Further Study Although a comprehensive investigation of these stormwater modeling programs is beyond the scope of this paper it is evident that the resulting hydrographs from TR20 HEC 1 HEC HMS and SWMM models can theoretically be interchanged provided that the hydrograph is in the correct format and provided that supporting information is available to describe the upstream watershed There may be additional modifications necessary to correct for certain idiosyncracies of each model but these should not be insurmountable In order to promote the exchange of watershed data a centrally located internet file server preferably run by PaDEP could be used to securely store and retrieve the modeling results of all PaDEP designated watershed studies By assigni
3. Collaborative Watershed Modeling using the Internet Modeling Large River Systems Andrew C Weaver P E Lancaster County Engineer s Office Introduction The concept behind the Pa Act 167 legislation is now commonly understood and accepted What the Act proposes is that for a given watershed the developments developers nearest the bottom of the watershed should get rid of their runoff as quickly as possible without harming their streams before the peak flow from upstream reaches them For developers at the top of the watershed the goal is the opposite to delay the release of their water as long as is reasonably possible so that the lower subareas have more time to get rid of their water The ultimate result at the bottom of Subarea 107 100 Year Hydrograph the watershed is a hydrograph with a Time somewhat longer peak and a delayed 25 peak time as seen in the hydrograph at left At present the Pennsylvania 20 j Department of Environmental Protection PaDEP is advocating Existing groundwater recharge which would Future tend to reduce the volume of runoff and peak time delay but recharge requires care in limestone areas and large developments with streets will find it difficult to recharge all of their runoff BMP s can reduce the volume and timing of the hydrograph as well but at this time there are few hard numbers to show what effect they have especially in larger storms At any rate with or without infi
4. e watershed By using these 6 files Stremtul can completely describe a watershed Compatibility with Other Hydrology Programs The files exported by Stremtul are not presently compatible with other watershed modeling software and were not intended to be However it appears that most of these other programs allow the user to import entire hydrographs from sources outside of the modeled area Although there is more to merging projects than just inserting a hydrograph time increments must match for instance the following information shows that it is possible to import hydrographs into a variety of modeling programs this is not a comprehensive list nor is it a detailed investigation The main point of interest is that it is possible to link different watersheds together using different modeling software A few of these programs and the ways by which hydrographs can be inserted into the models are HEC 1 Flood Hydrograph Package U S Army Corp of Engineers a hydrograph from an upstream model can be input using the following lines KK 100 KM HYDROGRAPH FROM UPSTREAM MODEL BA 35 1 QI 24 24 24 26 33 50 86 189 376 516 QI 594 657 710 760 801 839 910 1044 1287 1921 QI 2995 3953 4599 5077 5363 5374 5099 4603 3980 3325 QI 2719 2200 1844 1540 1251 994 ET 605 471 365 QI 281 0 0 0 The KK line starts a new computational block KM provides a place to label the hydrograph BA gives the basin area in square miles HEC
5. e if and how this was done The first is called Northali dft and the second is called Northarr dft the files are virtually identical Five of the six lines are used to describe the characteristics of the tracking storm on 10 36212 5 8 280 645 1 83 on 10 36212 5 8 280 645 1 83 Is the storm tracking turned on or off The actual watershed scale compared to the screen scale Storm direction 1 8 with 1 North and 4 South Storm tracking speed in mph Not used Storm tracking icon location Time hr s for the storm to track across the watershed In the example above the two files are identical but this isn t always the case The first file Northarr dft is a snapshot of the settings made when TR20 was last run The second file Northarr dft is the settings when FTP export was selected this was to avoid some obscure problems when the various settings used for the constituent watersheds were checked against one another Another file exported is called proj txt and includes general useful information about the watershed Mill The name of the watershed 08 10 2001 3 49 46 PM The time when tr20 was last run 05 08 2000 10 44 56 AM The time when the project was created 08 10 2001 3 58 35 PM The time when the project was exported Lastly if any Antecedent Moisture Condition AMC in the watershed was edited a file called lastamc txt is exported It contains only one line which is the AMC of the last subarea in th
6. ind the information itneeds nternet import export window in Stremtul without any additional input After a watershed model is run using the FTP Export button allows the user to send their most recent watershed model results to a remote computer connected to the internet By exporting the model results someone else can possibly incorporate those results into their watershed model The only restriction is that the owner of the remote computer must provide permission to connect permission to write files to their computer and a directory where the files can be written As with linking to a remote computer the first time the results are exported involves manually entering the URL address of the computer as well as a user name and password and browsing to the directory where the link information will be stored Stremtul will store this information and make it the default the next time the results of the watershed model are exported The information used to summarize the watershed model consists of at most 70 kB or so of hydrographs and other information The hydrographs are in standard TR20 format containing the starting time time increment and the upstream area in square miles There is also room to provide a base flow although none was entered in the hydrograph below The exported hydrograph has the format shown below the middle of this hydrograph was removed to save space T Logon as Anonymous User Connecting to ftp 128 36 200_43 mn
7. ltration and BMPs the watershed must be modeled in some way to determine peak flows volumes and timing so that a runoff control strategy can be developed and problem sites can be identified and mitigated In conformance with Act 167 Pa DEP has divided the entire state into over 300 watersheds A watershed wide storm water management plan is to be provided for each of these watersheds with the goal of having no increase in peak flow after the watershed is fully developed at some time in the future Each of these watersheds will most likely follow the accepted theory that the upper reaches of the watershed should delay their runoff and the lower reaches should facilitiate the flow of runoff to the receiving waters In addition to dividing the State into over 300 watersheds Pa DEP placed these watersheds into 13 Major River groups such as the Allegheny Monongahela Juniata Schuylkill and Lehigh Rivers These 13 major groups feed into 3 major rivers the Ohio Susquehanna and Delaware and are at the headwaters of 3 other major bodies of water Lake Erie Genesee and Potomac Rivers Thousands Hydrograph showing delayed peak and increased volume after development When comparing one of the 300 delineated watersheds to a map of a major river such as the Schuylkill the major difference is the scale of the watershed In the figure at right is Mill Creek one of the PaDEP delineated watersheds which covers 57 sq miles in one count
8. ng each watershed a unique number anyone could find the information they were interested in Security could be accomplished by preventing anyone but the County or entity responsible for a watershed from exporting information about it although anyone could import the information from the server The information stored could consist of the last most downstream hydrograph starting time time interval rainfall information storm direction storm velocity etc A committee of interested parties could develop a standard format for the information to be stored in Simple computer programs could take the standard results and adapt them to work in any hydrology program that allows the import of upstream data
9. r watershed This means that the results from the previous three watersheds must be merged into the model This merging of the watersheds will be greatly facilitated by the fact that all of the watersheds involved are primarily located in Lancaster County In a larger river system the constituent watersheds would not be located in the same county so some type of collaboration would be necessary Single Computer Modeling of Large Watersheds using TR20 The staff of the Lancaster County Engineer s Office uses TR20 to model the PaDEP designated watersheds and an in house developed Visual Basic program called Stremtul as a front end for TR20 The most recent version of Stremtul is 2 3 Stremtul allows point and click to create a link from one project the Conestoga River known as the Parent to as many as 10 upstream projects the Mill Little Conestoga and Cocalico Creeks known as the Children This means that Stremtul will insert the most recently run hydrograph from a Child project into the Parent project at the location where the link was set If a Child project is then loaded and some of the settings changed the resultant hydrograph at the pour point will also change after the model is run The next time the Parent project is loaded and run STREMTUL will see a link to the Child project go to the Child project get the last hydrograph for the pour point of the watershed and insert that hydrograph into the Parent s TR20 input file
10. rsheds are modeled by people who know the area 3 More people can contribute to the model making the process faster This also means that the smaller designated watersheds are updated relatively frequently so the major river watershed if modeled collaboratively would have fresher data than if it was modeled in one big piece Internet Modeling of Large Watersheds using TR20 As stated previously the Stremtul front end for TR20 can merge numerous watersheds by creating links between a Parent watershed and up to 10 Child watersheds located on the same computer or network Stremtul also allows these links to be created over the Internet Stremtul accomplishes this by using its own FTP File Transfer Protocol sub program The heart of this sub program is the Internet Transfer Control included with Visual Basic If the amp Internet FTP Operations AE x 12 Data has been seceived 7 Time out after 20 s user creates a project and wants to include a link to Dicctow Path i mnt k strembul a remote sub project or Child they must have pisope OSes Clete Satees permission to access that computer and will need the URL address of the computer as well as a user name and password The user also needs to know where on the remote computer the link information is stored Stremtul then stores this information with the project the password is encrypted so that next time it can connect to the remote computer and f
11. t engwork stremtul READHD 8 1 OMWWOMMWMAMOMM MOO OM OO ENDTBL READHD 9 11 5000 0 3a 10 Sit 100 1213 11102 10342 9251 8 4 2 1 XS 1 04 1000 57 4000 0000 Al S1 T 1 1 2 4 Da 6 8 13 16 20 25 39 48 60 TD 150 265 491 820 1664 2130 2596 3121 10988 10852 10698 10528 10143 9934 9715 9487 9008 8761 8511 8260 7 6 5 5 4 Fn 3 2 Dis 1 1 Ix 1 1 1 0 Each hydrograph is about 5 or 6 kB in size Although TR20 provides a hydrograph for each subarea only the last hydrograph is necessary for the downstream watershed so this is the only hydrograph exported In addition to the hydrographs several other small files are exported to the remote computer to describe the watershed The first one is the defaults file dflt2_3 txt not all of the settings are used just the ones that influence the last hydrograph from the subarea Only 9 of the first 10 lines are used and these are shown here yes Antecedent Moisture Condition AMC 100 Year Rainfall Intensity x 10 50 Year Rainfall Intensity x 10 25 Year Rainfall Intensity x 10 10 Year Rainfall Intensity x 10 5 Year Rainfall Intensity x 10 2 Year Rainfall Intensity x 10 Time increment in hours Not used Number of subareas Were small 2 50 yr storms run Yes or no Since Stremtul allows a watershed to be modeled with a storm tracking across the watershed two files are used to describ
12. the foundation engineer to design the foundation the other professionals can assume that the foundation engineer will make it work This method of collaborating does not work as well for hydrologists who could also use the internet to collaborate on a large project i e by modeling different parts of the same large watershed but are in the unique position of being governed by a certain law of nature water flows downhill This means that a hydrologist at the bottom of the watershed must wait for the upstream modeling to be finished before beginning his or her own model Because of this the schematic for internet collaboration by hydrologists would look more like a tree with the ultimate goal the modeling of the entire watershed at the base of the tree By using the Internet theoretically any number of watershed models could be combined to model very large watersheds The advantage of doing this is that l Modeling the larger watershed in pieces makes the task more manageable for any one County to model the Schuylkill River would be a monumental task but the 11 PaDEP watersheds that drain into the river are or soon will be modeled individually by the various counties they are located in 2 The information for the smaller designated watersheds is gathered kept and updated locally this means for example that changes in the watershed are known to the local government and can be added to the model Also the designated wate
13. y Lancaster Below that is the Schuylkill River watershed which covers 1 916 square miles in 11 counties including Philadelphia County The Schuylkill River watershed encompasses 17 PaDEP designated watersheds If the DEP delineated watersheds in the Schuylkill River basin are considered as subareas then it is apparent that the same p a conditions apply as far as runoff timing If the F Ha d ps runoff at the bottom of the Schuylkill River is Sy P a not gone before the peak flow comes from an e a ean upstream future development could cause an E cr m O eg P r increase in peak flow The effect of Pa Act 167 EAR a n oe is unknown in these large watersheds because O aon be they have not been studied The sheer size of ner Oi ae lt gt these watersheds makes them difficult if not We gt S impossible for one entity to model with any ao f degree of precision Schuylkill River Watershed On a smaller scale the Conestoga River is a small river that runs through Lancaster County and drains into the Susquehanna River near Pennsylvania s border with Maryland The Conestoga River watershed consists of 4 DEP delineated subwatersheds for the three creeks that drain into the Conestoga Mill Little Conestoga and Cocalico and the remaining area which is designated as the Conestoga River watershed The Lancaster County Engineer s Office has completed studies on the three creeks and will next begin work on the entire Conestoga Rive
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