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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Invasive Species and Pollinator Health » Research » Research Project #430137

Research Project: Assessment of Agricultural Pesticide Use and Water Quality Modeling to Predict Aquatic Weed Growth

Location: Invasive Species and Pollinator Health

Project Number: 2030-22000-029-16-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 1, 2016
End Date: Aug 31, 2019

1. To continue to carry out pesticide use data analysis to examine the use patterns of a selected group of pesticides in the Sacramento and San Joaquin River watersheds. 2. To model nitrate runoff through SWAT for the Sacramento and San Joaquin River watersheds. 3. To inform the USDA-ARS SWAT (Soil Water Assessment Tool) modeling conducted by the Cooperator and by NASA-Ames collaborators to quantify the exposure risks, to understand the use loads of the pesticides used in the area, in general, as well as the use patterns of selected pesticides. 4. To use the modeling results to investigate the exposure risks of some pesticides through offsite movement to streams and rivers.

The Cooperator at UCD-LAWR will query the pesticide use and monitoring data for Sacramento River watershed and assess the pesticide use types for the region and then we will explore the high use pesticides individually. The Cooperator can also map these high use pesticides to identify the spatial variations within the watershed, and to pinpoint a group of pesticides that have high potential impact on the aquatic weeds in the Delta. These pesticides will be candidates for SWAT modeling to assess the exposure risks. The AGIS lab at UC-Davis LAWR under Dr. Zhang has many years of experience working with SWAT model for pesticide runoff assessments in both Sacramento and San Joaquin watersheds. The Cooperator will update weather and other inputs and run the model that was previously calibrated and validated for the selected pesticides that impact the three main weeds (Giant reed, Brazilian Egeria, and Water hyacinth). The Cooperator will generate preliminary results using the previous SWAT version and communicate them back to collaborating scientists at NASA-ARC. The Cooperator will then explore the new version of ArcSWAT to delineate watershed boundaries, re-calculate HRUs and re-calibrate the model with new parameters. The cooperator will work with the team members to publish research results to share with wider audience. Revised per Amendment#2: The Cooperator will complete validation of the Soil Water Assessment Tool (SWAT)-based models for nitrate runoff from tile drains in the San Joaquin River and from the Sacramento River watershed. Validation will also be completed for models of runoff of one or two key pesticides from each watershed, for example, d.iuron from the San Joaquin watershed. Validation will consist of comparison of model runs to known nitrate runoff data and weather/water flow data from the downstream outlets of each watershed. Completed models will be delivered to NASA collaborators to provide input for their Delta-SWAT model. The Cooperator will participate in runs of that model and will provide input into the use of model output to predict aquatic weed growth.