Effects of spatial detail of soil information on watershed modeling

The impacts of detailed and spatially continuous soil information on hydro-ecological modeling over watersheds of mesoscale size are investigated. The impacts were assessed by comparing the simulated hydro-ecological responses based on the detailed soil spatial information derived from a fuzzy logic-based inference approach with those based on the soil information derived from a conventional soil map. This study reveals that the detailed soil spatial information has impacts on the simulated hydro-ecological responses under a lumped parameter approach. Peak runoff was reduced, yielding more realistic hydrographs for forested watersheds in the area. The detailed soil spatial information strongly impacted the simulation of net photosynthesis over the period when there is a moisture stress, but negligible impacts when there is sufficient water recharge to soil profiles. Simulation of hydro-ecological responses using a distributed parameter approach is less impacted by the detailed soil spatial information. The difference in simulated net photosynthesis under the distributed approach is smaller and also only occurred during the period of moisture stress. The impacts on spatial distribution of simulated transpiration occurred mainly over south facing slopes during the period of moisture stress.