High resolution, regional erosion modeling for critical source area identification.
Abstract
Variable source hydrology in Mediterranean climates on agricultural land produces critical source areas of nonpoint pollutants (i.e., sediment). Erosion on these areas is difficult to effectively control with conservation efforts at scale. Watershed level identification and treatment can be greatly improved with model simulation. In this project, we spatially distributed results of a hydrologic characterization tool using the Water Erosion Prediction Project (WEPP) model to visualize long term average erosion rates and the locations of critical source areas. Land types consisting of soil, slope, slope length, climate, and management derived from publicly available, spatial data were used to characterize the heterogeneity across the watershed at 30 m resolution. We bridged from the regional to sub field scale by using representative WEPP hillslope profile simulations for each unique combination of the land type data. The spatial land type data also characterized each flow path in the watershed and simulations were mapped to space by a characteristic naming convention and cell by cell steps down each flow path corresponding to modeled Overland Flow Elements. We evaluated multiple aggregation methods for accumulating flow paths and found the use of the mean strongly deviates from the maximum and sum for more than three accumulated flow paths. The land type characterization data were assessed by comparison to fully distributed parameters within the WEPP hillslope version and with a random forest. Steep, long slopes on shallow soils produced thresholds crossing high erosion rates. Slope shape, evaluated at the sub watershed, shifted the location of high erosion rates impacting predicted sediment delivery rates, but did not change the regional distribution of high erosion rates. The spatially distributed hydrologic characterization tool is a computationally efficient method for modeling erosion and critical source areas at the regional scale to aid local conservation efforts in focusing their outreach and planning.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.H11B..06F