Discrepancies between Hydropower model outputs between versions 2.5.6. and 3.3.3.
I have a question regarding the Water yield model in InVEST version 2.5.6. and 3.3.3.
I have run the model in both versions using exactly the same data/parameters and I obtained quite different results. In general, version 3.3.3. returned much lower water yield than version 2.5.6. (the ArcGIS toolbox version). To give you an example, from the pixel maps wyield output, it appears that paved surfaces did not generate any run-off according to version 3.3.3, and in version 2.5.6 run-off from these surfaces was substantial. Run-off from all remaining LULC classes (grassland, arable, woodland, etc) was again much lower in version 3.3.3., which appears a bit counter-intuitive.
I was wondering whether there are any reasons from the model's operational point of view for these differences? Looking at the user guides for both versions, it appears that the model principle has not changed so in theory both versions should return comparable results. Or could this be a matter of using certain parameters in the wrong order of magnitude in the 3.3.3. model?
Any help/insights on this will be greatly appreciated as I would like to understand the reasons behind the differing outputs!