Distributed watershed modeling of design storms to identify nonpoint source loading areas
- Princeton Univ., NJ (United States)
Watershed areas that generate nonpoint source (NPS) polluted runoff need to be identified prior to the design of basin-wide water quality projects. Current watershed-scale NPS models lack a variable source area (VSA) hydrology routine, and are therefore unable to identify spatially dynamic runoff zones. The TOPLATS model used a watertable-driven VSA hydrology routine to identify runoff zones in a 17.5 km{sup 2} agricultural watershed in central Oklahoma. Runoff areas were identified in a static modeling framework as a function of prestorm watertable depth and also in a dynamic modeling framework by simulating basin response to 2, 10, and 25 yr return period 6 h design storms. Variable source area expansion occurred throughout the duration of each 6 h storm and total runoff area increased with design storm intensity. Basin-average runoff rates of 1 mm h{sup {minus}1} provided little insight into runoff extremes while the spatially distributed analysis identified saturation excess zones with runoff rates equaling effective precipitation. The intersection of agricultural landcover areas with these saturation excess runoff zones targeted the priority potential NPS runoff zones that should be validated with field visits. These intersected areas, labeled as potential NPS runoff zones, were mapped within the watershed to demonstrate spatial analysis options available in TOPLATS for managing complex distributions of watershed runoff. TOPLATS concepts in spatial saturation excess runoff modelling should be incorporated into NPS management models.
- OSTI ID:
- 678074
- Journal Information:
- Journal of Environmental Quality, Vol. 28, Issue 2; Other Information: DN: Paper presented at the joint AGU Chapman/SSSA outreach conference on applications of GIS, remote sensing, geostatistics, and solute transport modeling to the assessment of nonpoint source pollutants in the vadose zone, October 19--24, 1997, Riverside, CA (US); PBD: Mar-Apr 1999
- Country of Publication:
- United States
- Language:
- English
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