Curve number

[Rita]

Hello I’m working with watershed of basins and floods…, I want to use the HMS across the WMS, the problem that I have is the next:

I have the curve number in format grid (ESRI)..and I don’t know use it in the wms. Help please!!

[Chris Smemoe]

Hi Rita,

The best way to use a CN grid in WMS is to convert it to polygon shapefile format. If you have ArcGIS, you can do this in Arc Toolbox by using the Conversion Tools...use the From Raster | Raster to Polygon command. Then use the Arc Toolbox to convert your polygon features to a shapefile. You can read the shapefile and its CN attributes into WMS. Once you have the shapefile in WMS, you can create a new Landuse coverage and convert your CN shapefile to the landuse coverage. Map the CN attribute as the land use ID, then just define Curve numbers for each land use ID and soil that match the ID. You will need a soil type coverage, but you can just create a new soil type coverage and draw a polygon around your whole model representing soil type and assign it a soil type of "A" (it doesn't matter what soil you assign it). Then, go to the hydrologic modeling module and select Calculators | Compute GIS Attributes, select the option to compute SCS curve numbers, use your land use coverage and soil type coverage, make sure your table looks right, and WMS will compute a composite CN for your watershed.

Hope this helps,

Chris

[Rita]

Hi Rita,

The best way to use a CN grid in WMS is to convert it to polygon shapefile format. If you have ArcGIS, you can do this in Arc Toolbox by using the Conversion Tools...use the From Raster | Raster to Polygon command. Then use the Arc Toolbox to convert your polygon features to a shapefile. You can read the shapefile and its CN attributes into WMS. Once you have the shapefile in WMS, you can create a new Landuse coverage and convert your CN shapefile to the landuse coverage. Map the CN attribute as the land use ID, then just define Curve numbers for each land use ID and soil that match the ID. You will need a soil type coverage, but you can just create a new soil type coverage and draw a polygon around your whole model representing soil type and assign it a soil type of "A" (it doesn't matter what soil you assign it). Then, go to the hydrologic modeling module and select Calculators | Compute GIS Attributes, select the option to compute SCS curve numbers, use your land use coverage and soil type coverage, make sure your table looks right, and WMS will compute a composite CN for your watershed.

Hope this helps,

Chris

Thanks!!!

All is right!!

Rita