UC Davis Department of Plant Sciences

Water Quality on US Forest Service Grazing Allotments

Contact Person: Dr. Kenneth W. Tate

Participants: Rob Atwill,Lea Kromschroeder, Donna Dutra, Mark Noyes, Scott Oneto, USDA Forest Service – Region 5, Stanislaus National Forest, Plumas National Forest, Tahoe National Forest, Shasta-Trinity National Forest, Klamath National Forest.

Comment or Questions?



This project focuses on surface water quality on U.S. Forest Service (USFS) grazing allotments in California (USFS Region 5). Concerns have been voiced about elevated fecal indicator bacteria (FIB) concentrations, and thus possible risk to public health, on several grazing allotments in the Sierra Nevada. Additional concerns have been raised about the potential for elevation of nutrient concentrations. The monitoring and educational program described here will evaluate water quality conditions, sources of water pollution, and guide management to improve water quality where needed.

Objective One


  We are conducting fecal indicator bacteria (fecal coliform and indicator E. coli) and nutrient water quality monitoring on 15 grazing allotments across five national forests in California to determine: 1) the quality of surface waters relative to the occurrence of activities such as livestock grazing, camping, and swimming; 2) specifically how USFS grazing management correlates with water quality; and 3) the association between water quality and hydrolic, soil and vegetation condition of streambanks and meadows (key grazing areas). (Objective 1 study description)



Objective Two


We will conduct waterborne pathogen (C. parvum, Giardia, pathogenic E. coli, and Salmonella) monitoring at the interface of livestock grazing, recreational activities (i.e., swimming), and drinking water locations (i.e., municipal water intake) to directly evaluate risks posed to public health by livestock grazing on key allotments. Details for this project will become available in mid-summer 2011.




Objective Three



Throughout the project we will conduct outreach to USFS staff, grazing managers and stakeholders on the topics of: 1) types, sources, transport, and fate of livestock derived pollutants; 2) assessment of management induced risk to water quality; 3) grazing management practices to mitigate risk and improve water quality; 4) development, implementation, and interpretation of monitoring to support adaptive management to improve water quality; and 5) integration of best available science into the management planning process.



Timeline and Project Status


Summer 2010: This project began in July 2010 with the initiation of stakeholder outreach field days and a pilot monitoring study of 3 grazing allotments on the Stanislaus National Forest. The purpose of the pilot study was to inform studies to address Objectives 1 and 2 in summer 2011. Specifically our objectives were to: 1) develop a watershed scale pollutant source search methodology for grazing allotments; 2) determine water sample collection, sample handling and transport, and laboratory analysis challenges and solutions for sampling in remote forest locations; and 3) provide preliminary data on the levels of FIB and nutrients to be expected in samples.

During the summer of 2010, we also evaluated the effect of holding samples on ice up to 24 hours on fecal indicator bacteria analysis and found no effect. Ideally, sample holding time, the time from collection until processing in the laboratory, for fecal indicator bacteria analysis is less than 8 hours. (sample hold time analysis).





Winter 2010/11: During the winter of 2010/11, we conducted outreach to stakeholders, USFS managers, and grazing managers about the objectives, scope, and timeline for the project (Sonora Presentation). We finalized plans for a 15 allotment study designed to achieve Objective 1. We established 3 remote analytical laboratories to allow analysis of water samples for fecal indicator bacteria concentration within 8 hours of collection, required to achieve Objectives 1 and 2.

Summer 2011: Starting June 2011 we are conducting intensive watershed scale pollutant source search monitoring on 15 grazing allotments on 5 national forests, including a total of 192 sample locations.  These 15 allotments are a representative cross-section of grazed allotments across the Region. This study is specifically designed to address Objective 1 of the project (summer 2011 study design). We are currently finalizing development of a targeted study to address Objective 2 – for implementation mid-summer 2011.

Winter 2012: Following completion of monitoring and laboratory analysis in early fall 2011, we will conduct statistical analysis and interpretation of the data collected during summer 2011 and share these results with USFS managers and interested stakeholders. We will prepare research papers reporting the results of the summer 2011 studies and submit for publication in appropriate peer-reviewed journals.

Please revisit this site for updates on the latest progress and results of the project. Please contact us at anytime for more information about the project.





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