Soil depth raster

I am carrying out the hydrological modeling in a basin that has a part in an urbanized area, that is, a part is in the city, and I have doubts about the values of soil depth for the area, since I have zero values for the urban area, also no I have root depth values for the urban area and I don’t know if these zero values can alter the results, the question is what should I do with the urban area that I have within the basin since it is a significant part of the basin .

Are you using the Annual Water Yield model? If so, one thing of note is that this model (and all of our freshwater models) is mainly appropriate where urban areas cover a relatively small amount of the study area. Hydrology is very different in urban areas, which is why we have a separate set of tools for the urban context.

For root depth in urban areas, we usually estimate that based on whatever vegetative cover might be there. If it is industrial, with no vegetation, then a root depth of 0 makes sense. If there are parks, yards, and other green space, then we will often average the root depth for forest, grassland, or other relevant vegetation types, based on the percentage of area covered by vegetation versus development. For example, if we estimate that 10% of an urban land cover type is vegetated with trees, then we’ll multiply (.1 * root depth for forest) and use that value as the root_depth parameter for that urban land cover type.

Soil depth is a little trickier. Again, if it’s all paved, then I’d say it’s safe to assign a soil depth value of 0, since all of the precipitation will run off. Otherwise, I will often assign the soil depth for urban to the depth value that is assigned to soils nearby outside of the urban center (which it sounds like is missing soil data).

~ Stacie

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