Generating Model Input with GIS

1
Generating Model Input with GIS

• The key elements for creating appropriate model
  inputs for rainfall-runoff models
• Input parameter requirements
• Available data sources
• GIS tools functions
• Data formatting for model entry

2
Input data requirements for TR-55

• Watershed location
• Land cover/land use
• Soils hydro group
• Time of concentration
• Watershed length
• Watershed land slope
• Flow type(s) (sheet flow, overland, channel)
• Mannings n
• Channel info
• Channel dimensions
• Stream velocity
• Stream reach data
• Length
• Mannings n
• Slope
• Channel dimensions
• Structure data
• Stormwater pond dimensions
• Outlet characteristics

3
Default parameters for TR-55

• Precipitation data (set rainfall returns)
• Set event duration (24 hrs)
• Rainfall distribution
• Unit hydrograph
• Curve numbers by land use

gtgtgtAre these values or settings appropriate for
my location???
4
Available data sources

• UVM GIS storage
• \\zoofiles\gisdata
• Vermont Center for Geographic Information
• http//www.vcgi.org/dataware/
• Vermont Mapping program (ortho and aerial photos)
  
• http//www.state.vt.us/tax/mappingcoverage.shtml
  
• UVM Map library
• Various national agencies/data sources
• USGS, NWI, Census/TIGER, etc
• National Geospatial Data Clearinghouse
• Resources constantly changing, improving,
  growing!

5
GIS tools functions

• Geographic extent
• Selecting data
• Exporting new data sets
• Clipping
• Data projections
• Joining/merging data
• Conversion tools
• Vector to raster, raster to shape files, etc.
• Raster calculations
• Reclassify
• Simple math functions
• Tabulate areas
• Arc Hydro capabilities
• Watershed delineation
• Flow paths
• Slopes

6
Data formatting for model input

• Specific file formats or structure
• ASCII
• .dbf
• Grid layers
• Manual entry (TR-55)
• Proper units !