Wateryield accumulation point

Science & Research
1

Dear Sir,

Please, how can I get the cell(s)/zone with the highest water yield in relation to flow direction/flow accumulation of my watershed for the purpose of locating a suitable area for my hydropower project?

Thank you

2

Hi @ADIGUN -

Which model are you using for water yield? Either way, I think it’s safe to say that the highest water yield will be at the outlet of the watershed.

This isn’t something I’ve ever done, so I’m just thinking out loud here. If you need to look inside the watershed to find sub-watersheds with non-maximum high yield, that seems like a much more complex task, that would require something like creating multiple sub-watersheds (perhaps even one for each pixel along the stream) and summing water yield within each one, to find the sub-watershed/pixel with highest value.

If you use ArcGIS, you might also be able to make use of the Flow Accumulation tool, which takes a weight raster that could be the water yield model output. (QGIS might have similar functionality).

~ Stacie

3

Dear @swolny,

Thank you so much for this great suggestion.

I used the InVEST model for my Water yield. The last paragraph made my day but since the weight rasters are in the range of 0-1 based on the percentage of water removed from the study area. How can I convert my water yield to weight raster to get an outstanding result? Thank you.

4

Respected @swolny ,

Thank you so much for this great suggestion.

I used the InVEST model for my Water yield. The last paragraph made my day, but since the weight rasters range 0-1 based on the percentage of water removed from the study area. How can I convert my water yield to weight raster to get an outstanding result? Thank you.

5

If you’re using the Flow Accumulation tool, I think the weight raster can have values larger than 0-1, so you could input the water yield output raster directly (or, perhaps more accurately, first convert them from millimeters to cubic meters, but that’s not as important if you just need relative values of high-low).

And are you using the Annual Water Yield or Seasonal Water Yield model?

~ Stacie

6

Respected @swolny

Thank you for the information. I am using annual water yield as my weight raster. More so, can I get change in hydraulic head from DEM only if preprocess in ArcGIS

Thank you