NITRATE AND PESTICIDE GROUNDWATER CONDITIONS BENEATH THE WASI PLATTEVILLE PIONEER FARM

• Sponsoring Institution: State Agricultural Experiment Station
• Project Status: COMPLETE
• Funding Source: STATE
• Reporting Frequency: Annual
• Accession No.: 0207082
• Project Start Date: Jul 1, 2005
• Project End Date: Jun 30, 2007
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIV OF WISCONSIN
21 N PARK ST STE 6401
MADISON,WI 53715-1218

Performing Department
SOIL SCIENCE

Non Technical Summary
Agriculture profoundly influences groundwater quality. Little work has been done at the field study as to the transport of agrichemicals to groundwater in the environment typical of southeast Wisconsin. Determine the groundwater impacts of agricultural systems that prevail in southeast Wisconisn.

Animal Health Component

100%

Research Effort Categories

Basic

(N/A)

Applied

100%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
112	0320	2050	100%

Knowledge Area
112 - Watershed Protection and Management;

Subject Of Investigation
0320 - Watersheds;

Field Of Science
2050 - Hydrology;

Keywords

groundwater

nitrate

pesticide

Goals / Objectives
The purpose of this project is to gain insight into field-scale nitrate and pesticide groundwater impacts of agriculture in the region represented by the Pioneer Farm, and to fold this insight into WASI's research and outreach efforts directed toward agricultural practice improvement. Project goals are to (1) provide an initial assessment of hydrogeology at the Pioneer Farm, and (2) describe nitrate and pesticide impacts on Pioneer Farm groundwater. These goals will be accomplished through the following objectives: 1. Describe site lithology. 2. Describe hydraulic properties of rock. 3. Describe the hydraulic head distribution and flow of groundwater on the site. 4. Characterize the temporal change in aquifer heads and their relation to recharge events 5. Measure water quality, both general geochemistry and nitrate and pesticide content.

Project Methods
We will access the subsurface through eight boreholes installed to about 16 m. Borehole locations will be chosen to provide a representative view of groundwater conditions on the farm. A geoscientist will be on site during drilling to maintain a log and to collect cuttings. Cuttings will be processed and described by the Wisconsin Geological and Natural History Survey (WGHNS). Boreholes will be geophysically logged (caliper, gamma, resistivity, fluid conductivity, temperature, and flowmeter) through arrangements with WGNHS, to discern the nature of rock permeability and distribution of permeable zones. After logging, 2-3 piezometers will be installed in each boreholes at discrete intervals of higher permeability. Hydraulic conductivity testing will be performed in the screened zones. Hydraulic head, temperature, and specific conductance will be monitored continuously in 6 piezometers, using Levelloggers (Solinst, Georgetown ON) or equivalent instrumentation. These data, in conjunction with weather station information, will allow an assessment of temporal head and water quality changes in response to recharge events. Continuous monitoring devices will be stacked in the piezometers of two boreholes so that the aquifer response with depth from recharge events can be assessed. Monthly head measurements will be made manually on piezometers without continuous monitoring equipment. Head measurements, augmented with Fever River elevations, will be used to infer groundwater flow direction. Our water quality monitoring plans can be categorized into three types based on frequency, parameters, and breadth: Type 1 - Routine monitoring. Frequency - monthly. Duration - 15 months. Number of piezometers for sampling - all. Parameters - Cl, NO2+NO3-N, pH, specific conductance, hydraulic head. Type 2 - General geochemical characterization. Frequency/duration -twice over two years. Number of piezometers for sampling - 12. Parameters - in addition to Type 1 parameters, Al, Ca, Mg, K, Na, Mn, Fe, Si, P, S, and total Kjeldahl N, NH4, acid neutralizing capacity, dissolved oxygen, dissolved organic carbon. Type 3 - Pesticide characterization. Frequency/duration - twice over two years. Number of piezometers for sampling - six. Parameters - Atrazine, atrazine metabolites, and 28 other pesticides will be analyzable by GC/MS (modified EPA Method 8270). Chloroacetanilide herbicide metabolites (those of alachlor, metolachlor, and acetochlor) analyzable by using solid-phase extraction and high performance liquid chromato- graphy/diode array detection (generally described by Zimmerman et al., 2000).

Progress 07/01/05 to 06/30/07

Outputs
OUTPUTS: The project sought to learn about field- to watershed-scale leaching of pollutants to groundwater and subsequent pollutant transfer to surface water in the challenging southwest Wisconsin physical environment. The study site was at the University of Wisconsin Platteville Pioneer Farm, and was conducted with partners there, at UW-Stevens Point, and with the UW Discovery Farms. The groundwater of southwest Wisconsin is greatly impacted by nitrate and pesticide residues of agricultural origin, and these contribute to the continental scale export of pollutants to the Gulf of Mexico, with attendant contributions to Gulf hypoxia. Though the region is known to be groundwater-quality challenged, little study of the issue had occurred there, perhaps mainly because of the expense and difficulty of instrumenting and monitoring the subsurface. This project led to a greater understanding of these influences. PARTICIPANTS: University of Wisconsin-Madison (Fred Madison), UW-Platteville Pioneer Farm (Tom Hunt), UW-Stevens Point (George Kraft), and UW Discovery Farms (Dennis Frame). TARGET AUDIENCES: Target audiences included other UW-System researchers who will assist in carrying on this work. Other target audiences for outreach efforts include Wisconsin ag producers, conservation professionals, urban and rural landowners, and various federal and state conservation agency staff. PROJECT MODIFICATIONS: No Project Modifications information reported.

Impacts
Our approach included first installing boring and conducting geophysics to understand generally the subsurface environment. Twelve boreholes were installed, each extending 14 to 84 m below the surface. Each borehole was lithologically and geophysically logged, including logging with an Optical Borehole Imaging instrument. Boreholes were instrumented with 2-5 piezometers screened at different depths. Groundwater was then monitored for a suite of constituents and hydraulic head. Monitoring indicated two major groundwater transport routes; through the upper (approx 10 m) part of the upper rock unit through enlarged bedrock solution features, and through a deep (greater than 75 m) sandstone. Groundwater in the shallow transport system contained up to 40 mg L of NO3-N. Concentrations in the deeper system were smaller, however, groundwater age dating indicates concentrations there will increase and be similar to shallow groundwater in perhaps 20-30 years. Additional work continues on elucidating the groundwater flow system through groundwater flow modeling, and describing pesticide pollution at the site.

Publications

• No publications reported this period

Progress 01/01/06 to 12/31/06

Outputs
In 2006, twelve boreholes were installed on the Platteville Farm, extending 42 to 254 feet below the surface. Each borehole was lithologically and geophysically logged, including logging with an Optical Borehole Imaging instrument. Each borehole was instrumented with 2-5 piezometers screened at different depths. One borehole was instrumented with a Flute multilevel access device. Piezometers were sampled for water levels and chemistry parameters on 4 dates.

Impacts
We expect to gain insight into field-scale nitrate and pesticide groundwater impacts of agriculture.

Publications

• No publications reported this period