HR: 1340h
AN: H13A-0394    [Abstracts]
TI: Combining Data and Process Models to Characterize Non-point source Pollution to Shallow Ground Water from an Irrigated Dairy Farm
AU: VanderSchans, M L
EM: martin.mwbq@iucnlao.org
AF: IUCN-The World Conservation Union, Mekong Wetlands Biodiversity Programme PMY; 16 Fa Ngum Rd; PO Box 4340, Vientiane, 000 Lao People's Democratic Republic
AU: * Harter, T
EM: ThHarter@ucdavis.edu
AF: University of California, Dept. of Land, Air, and Water Resources, Davis, CA 95616-8628 United States
AU: Leijnse, A
EM: a.leijnse@nitg.tno.nl
AF: Wageningen University, Subdept. of Water Resources, Nieuwekanaal 11, Wageningen, PA 6709 Netherlands
AU: Mathews, M C
EM: mcmathews@ucdavis.edu
AF: Univ. of California Coop. Ext., 3800 Cornucopia Way, Suite A, Modesto, CA 95358 United States
AU: Meyer, R D
EM: rdmeyer@ucdavis.edu
AF: University of California, Dept. of Land, Air, and Water Resources, Davis, CA 95616-8628 United States
AB: The objective of our work is to characterize non-point source nitrate leaching from a dairy farm located in a relatively vulnerable hydrogeologic region of California. We consider sub-management unit, management unit (fields, corrals and ponds) and farm scale processes. Available data consists of measured fluxes/heads and nitrogen concentrations in a tile drainage and monitoring well network. Of concern is that there are several scales of measurements and processes that are difficult to relate due to high spatial and temporal variability of the leaching processes and the varying area represented by each of the measurements (measurement support). The focus of our modelling approach therefore lays on the development of several three-dimensional process based groundwater flow and transport models that are jointly capable of characterizing in-farm pollution variability and accommodating different types of data with varying measurement support for their calibration and validation. Estimated average leaching is 486 kg/ha/yr, 695 kg/ha/yr and 807 kg/ha/yr for field, corrals and ponds respectively. Aggregated results of the simulations are also compared to field and farm scale nitrogen balances and nitrogen discharges from tile drains and assessed in relation to their data requirement and measurement support scale.
DE: 1829 Groundwater hydrology
DE: 1831 Groundwater quality
DE: 1832 Groundwater transport
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting