HR: 17:36h
AN: H44B-09    [Abstracts]
TI: Rainfall-Runoff Modeling to Compare Hydrological Processes Governing Solute Transport in Five Different Agricultural Watersheds
AU: * Linard, J I
EM: jilinard@usgs.gov
AF: U.S. Geological Survey, 100 Centennial Mall North Rm 406, Lincoln, NE 68508 United States
AU: Webb, R M
EM: rmwebb@usgs.gov
AF: U.S. Geological Survey, Box 25046, MS 413 Denver Federal Center, Denver, CO 80225 United States
AU: Wieczorek, M E
EM: mewieczo@usgs.gov
AF: U.S Geological Survey, 8987 Yellow Brick Rd, Baltimore, MD 21237 United States
AU: Wolock, D M
EM: dwolock@usgs.gov
AF: U.S. Geological Survey, 4821 Quail Crest Place, Lawrence, KS 66049 United States
AB: Non-point sources of fertilizers and pesticides from agricultural areas can impair the water quality of streams. A better understanding of how hydrological processes affect the transport of agricultural chemicals to streams is required to improve management of fresh water resources. Examining how hydrological processes vary in agricultural landscapes and subsequently affect solute transport is a focus of the U.S. Geological Survey's (USGS) National Water Quality Assessment (NAWQA) Program. As part of the NAWQA Program, the quantities of precipitation, irrigation, recharge, ground water, seepage and streamflow are being monitored along with reported application rates of agricultural chemicals within five agricultural watersheds in California, Washington, Nebraska, Indiana, and Maryland. Two quasi-distributed hydrological models capable of simulating solute transport (the Soil and Water Assessment Tool (SWAT) and the Water, Energy, Biogeochemical Model (WEBMOD)) were applied to each watershed. Although the underlying environmental processes were represented differently in each model, both models were capable of simulating the expected hydrological characteristics and dominant flow paths in each watershed. In each model, the relative contributions of infiltration-excess overland flow, saturation-excess overland flow, shallow subsurface flow, preferential flow, and deep ground water flow were estimated. These fluxes then were compared to measured in-stream solute concentrations to assess how each hydrological flow path affected water quality. Generally, soil profile characteristics, land management practices, and irrigation methods regulated hydrological connections between watershed hillslopes and receiving streams.
UR: http://water.usgs.gov/nawqa-only/act/index.html
DE: 1836 Hydrologic budget (1655)
DE: 1860 Runoff and streamflow
DE: 1866 Soil moisture
DE: 1871 Surface water quality
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting