[GRASS-user] Interpreting r.watershed accumulation map

[Rich Shepard]

On Tue, 11 Oct 2016, Laurent C. wrote:

> It seems to be a problem from within the temporal framework. I never had
> this specific problem before, but I've run into some other obscure errors
> using TGRASS.

   To summarize my understanding: Itzi will not work with my current data
because of some issue with a tgrass module; r.lake does show water
accumulation area by depth above a blockage at a defined x, y, z point; and
other r.* modules (e.g., watershed. water.outlet, and sim.water) require
defined stream channels. Have I missed a module that will map precipitation
accumulation and flow across flat agricultural lands?

   A major concern (at least in the US) is nonpoint-source runoff of
pollutants. One such land use is farmland. Regulators attempt to address
such nonspecific-source water quality concerns using total maximum daily
loads/limits (TMDL) to apportion maximum contributions of the parameter of
concern by each potential contributor.

   Is there a grass7 work flow that can be applied to this situation?

Rich