Last updated on 2022-09-28
Once an area of interest is selected, Model My Watershed automatically performs geospatial analyses on mapped data layers within the area. Summary statistics are provided in graphs and tables for each of these data layers that impact stormwater runoff and/or water quality:
5.1 Streams
For more information on data sources, see Section 3.1 Layers: Streams.
Stream length and mean channel slope statistics are calculated for each stream order (sum of all segments belonging to a stream order in the area analyzed) from the Continental US Medium Resolution Stream Network.
Stream length in agricultural and non-agricultural areas is calculated using an implied riparian width of approximately 30 m, and an implied buffer of approximately 15 m, using the following methodology:
A stream vector line is rasterized to a 1 pixel string, with pixels the same size as an NLCD pixel (30m). Under the hood, GeoTrellis uses Bresenham’s Line Drawing algorithm to rasterize a line to pixels. See the specific GeoTrellis code.
This approach therefore assumes an implied riparian width of approximately 30m, and an implied buffer of approximately 15 m.
5.2 Land
For more information on data sources, see Section 3.2 Layers: Coverage Grids.
Land cover distribution summary statistics for each land use category (Area, Coverage %, and Active River Area) are computed for your Area of Interest based on the 2011 National Land Cover Database. For Active River Area, the ARA coverage grid is used to segment/clip the land area in your Area of Interest to this layer and summarize land cover area within the “Active River Area – Northeast and Mid-Atlantic.”
Within the drop down selection list, the “Protected lands distribution” selection provides a summary of land Area and Coverage (%) for each Protected Lands category in that coverage grid for your Area of Interest.
Within the drop down selection list, the “DRB 2100 land forecast (Centers or Corridors)” selection provides a summary of land Area and Coverage (%) for predicted land cover by the year 2100 for your Area of Interest.
5.3 Soil
For more information on data sources, see Section 3.2 Layers: Coverage Grids.
5.4 Animals
For more information on data sources, see Section 3.6.1.
5.5 Point Sources
For more information on data sources, see Section 3.6.2.
5.6 Water Quality
(Delaware River Basin Only): For more information on data sources, see Section 3.2 Layers: Coverage Grids.
