Challenges in geographic information system and erosion model application in watershed management : the Bohol Watershed, Philippines

The use of geographic information system and erosion model techniques in land management assessment in the Upper Inabanga Watershed, Philippines is presented. The WEPP (Water Erosion Prediction Project) erosion model was applied to assess erosion at watershed and farm-scale levels. Erosion was predicted using simulated conventional and, alternatively, conservation-oriented agriculture practices, in terms of on -site and off-site effects of the agricultural practices. From instrumented trial hillslopes, sediment yield decreased from 32.8 t•ha-1 to 12.8 t•ha-1 under conventional farming to conservation-oriented practices, respectively. At the watershed level under current land use, this was translated into a decrease in sediment discharge from 11.9 t•ha-1 to 10 t•ha-1. With land use change in which 58% of the watershed area was allocated to agriculture cultivation, conservation oriented practices decreased sediment discharges from 32.1 t•ha-1 to 3.9 t•ha-1. The WEPP event-by-event output showed the temporal variation of soil loss over the simulation period. The study gives valuable insight to understanding erosion processes at different scales and conservation planning within watersheds. The study concludes that simulation and prediction of erosion under a wide range of scenarios and identification of specific locations of erosion prone areas is valuable for decision-making purposes and for designing conservation strategies

Redistribution of Soil Organic Carbon Induced by Soil Erosion in the Nine River Basins of China

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