For years, producers and water quality specialists have had concerns about fecal coliform bacteria runoff from dairy pastures into rivers and estuaries. “Best Management Practices” (BMPs) have been developed to reduce the transport of bacteria after manure application to pastures. Data shows producers are making progress on reducing runoff into some rivers throughout the Northwest. A major practice to reduce possible impacts of manure application on bacterial loading to waterways is a setback of the application area from the body of water. However, while this seems like an obvious recommendation to most, the distance of the setback and the benefits gained in water quality are not that clear. Photo by Scott Bauer, USDA-ARS. Used with permission. A number of studies have looked at the use of vegetative buffers or setbacks to reduce bacterial movement. The studies show a variety of results at different distances, from 100 percent filtering to almost no improvement, depending on the study. This is further complicated by differences in bacterial loading, soil conditions, microbial die off, rainfall intensity and amount, sunlight, and vegetation and soil organic matter. A research project was conducted recently in Tillamook County, Oregon to help understand the fecal coliform bacteria removal efficiencies of grass buffers of various sizes. This project involved the work and ideas of many, but was led by Dr. Tim Sullivan with E&S Environmental in cooperation with Oregon State University. The main concept tested the theory that for every incremental increase in buffer width, there should be a decrease in bacterial movement. Obviously, increasing the buffer width has major economic implications to the forage production on the farm so there is a cost/benefit relationship to the producer and to the environment. These researchers set out to determine the edge of field buffer widths that would simultaneously protect water quality and require the smallest loss of forage land. The study consisted of 18 treatment plots, each 45 feet wide and 100 feet long. The plots had grass growing on them and were setup to test buffer widths of 0, 3, 10, 25, 50, and 80 feet. These plots had not received manure for several years and were sloped with a gentle slope (3.8 percent) and a moderate slope (7.0 percent). Treatment plots were isolated from one another by ditches. At the lower end of each plot was a sampling device that captured surface runoff and shallow soil water movement through each plot. The project was conducted over 9 major storm events during a two year period. Manure was applied prior to a forecasted major storm event at different distances from the sampling device, simulating different manure setbacks. During the first storm, no manure was applied to test the sampling devices and monitor background bacterial information.

Pacific Northwest Regional Water Quality Coordination Project Partners Land Grant Universities Alaska Cooperative Extension Service Contact Fred Sorensen: 907-786-6311 http://www.uaf.edu/ces/water/index.html University Publications: http://www.alaska.edu/uaf/ces/publications/ Idaho University of Idaho Cooperative Extension System Contact Bob Mahler: 208-885-7025 http://www.uidaho.edu/wq/wqhome.html University Publications: http://info.ag.uidaho.edu/Catalog/catalog.html Oregon Oregon State University Extension Service Contact Mike Gamroth: 541-737-3316 http://extension.oregonstate.edu/ University Publications: http://extension.oregonstate.edu/catalog/ Washington Washington State University WSU Extension Contact Bob Simmons: 360-427-9670 ext. 690 http://wawater.wsu.edu/ University Publications: http://pubs.wsu.edu/ Northwest Indian College Contact Michael Cochrane: 360-392-4299 mcochrane@nwic.edu or http://www.nwic.edu/ Water Resource Research Institutes Water and Environmental Research Center (Alaska) http://www.uaf.edu/water/ Idaho Water Resources Research Institute http://www.boise.uidaho.edu/ Institute for Water and Watersheds (Oregon) http://water.oregonstate.edu/ State of Washington Water Research Center http://www.swwrc.wsu.edu/ Environmental Protection Agency EPA, Region 10 The Pacific Northwest http://www.epa.gov/r10earth/ Office of Research and Development, Corvallis Laboratory http://www.epa.gov/wed/ For more information contact Jan Seago at 206-553-0038 or seago.jan@epa.gov
	The Project Land Grant Universities, Water Research Institutes and EPA Region 10 have formed a partnership to provide research and education to communities about protecting or restoring the quality of water resources. This partnership is being supported in part by the USDA’s Cooperative State Research, Education and Extension System (CSREES). Our Goal and Approach The goal of this Project is to provide leadership for water resources research, education and outreach to help people, industry and governments to prevent and solve current and emerging water quality and quantity problems. The approach to achieving this goal is for the Partners to develop a coordinated regional water quality effort based on, and strengthening, individual state programs. Our Strengths The Project promotes regional collaboration by acknowledging existing programs and successful efforts; assessing program gaps; identifying potential issues for cross-agency and private sector collaboration; and developing a clearinghouse of expertise and programs. In addition, the Project establishes or enhances partnerships with federal, state and local environmental and water resource management agencies, such as by placing a University Liaison within the offices of EPA Region 10.
	Results from experimental treatment plots during nine rainstorms indicated that only 10 percent of the runoff samples had bacteria concentrations > 200 colony forming units (cfu)/100 ml, and the median runoff concentration for all plots was only 6 cfu/100 ml. If the manure soaked into the soil, bacteria did not leave the plots, even if the buffer was only three feet wide. The presence of a vegetated buffer of any size generally reduced the median bacteria concentration in runoff by more than 99 percent. Manure applications with no buffers averaged as high as 164,627 cfu/100 ml in the gentle slope plots. Authors concluded this result was largely due to the observed high rate of infiltration of precipitation, even during large storms. They also concluded that contamination of runoff from manure-treated pasture lands is strongly associated with specific field or management conditions, such as soils that have low water infiltration rates and generate larger volumes of runoff. Soil is highly effective at trapping and immobilizing bacteria if the manure application and consequential rainfall can infiltrate the soil surface. Current manure application recommendations are: 1) Make manure application schedules that account for cropping needs and site specific field characteristics; 2) Fields with poorer drained soils (lower infiltration rate) and fields prone to flooding should be scheduled for multiple manure applications early in the growing season during dry weather; 3) Fields that have higher infiltration rates and ones that are farther away from water ways should be the ones used during months with the potential for higher rainfall; and 4) Lighter, more frequent applications to fields with enough air space in the soil for the application to move into the soil profile is most desirable. A copy of the whole report can be downloaded at http://www.esenvironmental.com/download_site.htm.
	National Water Quality Program Areas The four land grant universities in the Pacific Northwest have aligned our water resource extension and research efforts with eight themes of the USDA's Cooperative State Research, Education, and Extension System. Animal Waste Management Drinking Water and Human Health Environmental Restoration Nutrient and Pesticide Management Pollution Assessment and Prevention Watershed Management Water Conservation and Agricultural Water Management Water Policy and Economics
	CSREES is the Cooperative States Research, Education and Extension Service, a sub-agency of the United States Department of Agriculture, and is the federal partner in this water quality program.

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