Guidelines for Managing Cattle Grazing in Riparian Areas to Protect Water Quality:
Review of Research and Best Management Practices Policy

by

Jeffrey C. Mosley,¹
Philip S. Cook,²
Amber J. Griffis,³
and
Jay O'Laughlin⁴

¹Dr. Mosley is Associate Professor and Extension Range Management Specialist, Department of Animal and Range Sciences, Montana State University, Bozeman, and was formerly Associate Professor, Department of Range Resources, University of Idaho, Moscow.

²Mr. Cook is Research Associate, Idaho Forest, Wildlife and Range Policy Analysis Group, University of Idaho, Moscow.

³Ms. Griffis was a part-time Research Assistant, Idaho Forest, Wildlife and Range Policy Analysis Group, University of Idaho, Moscow.

⁴Dr. O'Laughlin is Director, Idaho Forest, Wildlife and Range Policy Analysis Group, and Professor, Department of Forest Resources, University of Idaho, Moscow.

TABLE OF CONTENTS

LIST OF TABLES

LIST OF FIGURES

LIST OF SIDEBARS

EXECUTIVE SUMMARY

Riparian areas are lands adjacent to water bodies. Consequently, these lands are more moist and more productive than contiguous floodplains or uplands. Riparian areas provide a wealth of products and values including clean water, fish and wildlife habitat, recreational opportunities, and scenic beauty. These lands are also valuable sites for timber production, cropland agriculture, and livestock grazing. Appropriate management of riparian areas is thus a vital environmental and economic issue.

Livestock grazing in riparian areas is controversial. Many riparian areas in the United States have been mismanaged and degraded by improper livestock grazing. However, the negative effects of grazing in riparian areas can be minimized or eliminated with proper management. Grazing management is the key to attaining the benefits riparian areas offer livestock while maintaining water quality standards and fully functioning riparian ecosystems.

Water quality in many of Idaho's waters translates directly into conditions that support adequate habitat for fish. Protecting water quality and providing forage for cattle are only two of the many functions of land areas adjacent to water. This report addresses only the water quality protective functions of riparian zones. This is not to say that the many other values of riparian areas are less important than water quality, but these other purposes are not required by the federal Clean Water Act.

The purpose of this report is to provide management guidelines that will help livestock producers meet the goals of the Clean Water Act while grazing cattle in riparian areas. Depending on the current condition of a particular riparian area, this could mean that the producer may have to modify the timing, frequency, and intensity of grazing in order to maintain conditions that will protect water quality. These guidelines are based on a review of research results published in the scientific literature. That review is in Chapter 1 of this report. Best management practices, or BMPs, are the Clean Water Act's approach to minimizing the adverse impacts of livestock grazing and other land-use activities on water quality. The guidelines in this report may be useful for resource stewardship in riparian areas whether or not a livestock producer is following grazing management strategies that have been officially incorporated into BMPs. Chapter 2 of this report explains the origin and purpose of BMPs, and should be informative not only for producers considering their use but also for officials responsible for designing and overseeing the implementation of BMPs.

In addition, the overall policy context of livestock grazing and water quality in Idaho is addressed in Chapter 3. Two case examples from Idaho (Sawmill Creek and Clover Creek) illustrate the relationship between scientific research and on-the-ground BMP application.

This report attempts to reply to three focus questions about riparian grazing. In short, what management strategies are indicated by research, how are BMPs administered, and how does state policy protect water quality? The full questions and short summaries of the replies are given below.

Focus Questions and Short Replies

Three focus questions were developed by the Policy Analysis Group's Advisory Committee to serve as the outline for this report. Short replies follow, with full replies in each of the three chapters of the report for which the focus questions are chapter titles.

(1) What are appropriate management strategies for cattle grazing in riparian areas? Cattle grazing in riparian areas affects nutrients, fecal bacteria, sediments, streambanks, and vegetation in the riparian ecosystem, with associated effects on water quality. Appropriate management of grazing involves controlling the timing, frequency, and intensity of cattle use.

Riparian grazing plans should be site-specific and based upon the best research and empirical evidence available. Based upon a review of the research literature* the following guidelines are suggested as starting points for developing cattle grazing plans that will protect the functions of riparian areas that affect water quality:

1. To reduce negative impacts of grazing, determine the critical period(s) of a riparian site, and then limit grazing during the critical period(s) to no more often than once every 3 or 4 years. Critical periods and impacts are likely to be either in late spring-early summer, when streambanks are more easily broken down by trampling; or late summer-early fall, when excessive browsing may damage vegetation. Each site has its own critical period that should be individually determined. Important critical period variables are soil moisture, plant species composition, and animal behavior patterns. Sites may be grazed every year if use does not occur during the critical period(s). Extended periods of rest or deferment from grazing may be needed to enable recovery of badly degraded sites.

2. To maintain streambank stability, limit cattle access to surface water when adjacent streambanks and shorelines are overly wet and susceptible to trampling and sloughing. Streambank trampling can often be reduced by capitalizing on the natural foraging behavior of cattle. Cattle generally avoid grazing excessively wet sites or in cold-air pockets. Cattle seek out wind-swept ridges, and they graze on upland forage when it is more palatable than forage in riparian areas.

3. To increase vegetative reproduction, schedule cattle grazing to increase tiller (or sprout) density by periodically removing apical meristems (or growing points) in shoots of desirable plants. More vegetation reduces the transport of nutrients, fecal bacteria, and sediment in overland flow. If new plants need to be established and if the desirable plant species do not reproduce vegetatively, these plants should be allowed to reach seed maturity no less often than once every 3 or 4 years.

4. To graze a site more than once per growing season, moisture and temperature conditions should be conducive to plant regrowth. For such sites, allow a recovery period of at least 30 to 60 days, depending on vegetation type, before regrazing within the same growing season. Grazing more often and for shorter periods—that is, 3 weeks or less at a time—is preferable to fewer and longer grazing periods.

5. To control the timing, frequency, and intensity of cattle grazing, managers should consider creating smaller riparian pastures with similar, or homogenous, features. Adjusting timing, frequency, and intensity of grazing in individual pasture units is more important than adopting a formalized grazing system.

6. To protect streambanks, prevent cattle from congregating near surface waters. Fencing, alternative water sources, supplemental feeding, and herding work best. Inappropriate cattle grazing will usually first be evidenced by excessive physical disturbance to streambanks and shorelines.

7. To reduce impacts from cattle urine and feces, locate the edges of features where cattle congregate—such as salt grounds, water developments, and winter feeding grounds—away from surface waters to allow the filtering of runoff from heavy fecal accumulation areas through vegetation before the runoff enters surface waters. Although very little research exists, studies of manure-polluted runoff indicate that distances of at least 12.5 to 20 feet from surface waters may be appropriate depending on vegetative cover, soil type, slope, and runoff.

8. To sustain vegetation which protects water quality, herbaceous utilization levels of less than 65% are usually appropriate. Proper grazing intensity will depend on existing riparian condition, grazing system, and management objectives. Stubble heights will vary by type of vegetation. For example, in grazed units or pastures, leave an end-of-the-growing season stubble height of 3 to 4 inches for sedges, tufted hairgrass, and similar species, and 2 inches for Kentucky bluegrass. Large bunchgrasses such as basin wildrye will require 4 to 6 inches. Utilization of riparian shrubs should not exceed 50 to 60% during the growing season. Maintaining at least 50% protective ground cover—plant basal area, mulch, rocks, or gravel—is appropriate.

9. To protect banks and reduce impacts from cattle urine and feces, vegetation buffer strips usually should not be necessary when cattle are grazing in riparian areas unless (1) cattle congregate near surface waters to the point that protective ground cover is less than 50%; (2) trampling damage is causing excessive streambank sloughing; or (3) large amounts of feces and urine are being deposited in or immediately adjacent to surface waters. Where buffer strips are necessary to protect water quality, there is little guidance in the literature as to an effective minimum width. However, from studies of manure-polluted runoff widths of at least 12.5 to 20 feet on each side of the stream appear to be adequate to allow filtering of nutrients and bacteria depending on slope, soil type, vegetative cover, fecal concentration, and runoff levels. Water bodies adjoined by steep terrain may need wider strips.

Again, it should be emphasized that riparian grazing plans should be site-specific. These guidelines are principally useful for indicating what the water quality protective functions of riparian areas are, and some basic information that the grazing manager should consider. Given the high degree of variability across the state, neither these nor any other guidelines could serve to indicate what the specific dimensions of an appropriate grazing management plan would be.

(2) What are Best Management Practices? Idaho's water quality law defines best management practices (BMPs) as "practices, techniques or measures developed, or identified, by the designated agency and identified in the state water quality management plan which are determined to be a cost-effective and practicable means of preventing or reducing pollutants generated from nonpoint sources to a level compatible with water quality goals" (Idaho Code § 39-3602(2)).

In other words, BMPs are officially approved ways of controlling nonpoint source water pollution, or polluted runoff. BMPs include maintenance and operational procedures as well as structural and non-structural controls. BMPs must be technically and economically feasible and socially acceptable. Idaho law requires the implementation of BMPs for mining and forest practices; however, agricultural and livestock grazing BMP implementation is nonregulatory in nature. There is a back-up regulatory program for ensuring compliance.

For private landowners, a BMP is established and implemented by working with a resource specialist from the local Soil Conservation District or the local office of the USDA Natural Resources Conservation Service, or both. A BMP is actually comprised of one or more "component practices" that have been adopted by the Idaho Soil Conservation Commission and listed in the Idaho Agricultural Pollution Abatement Plan. Component practice descriptions provide general guidelines and criteria that are adapted at the local level to fit a specific site. A copy of one of these component practices, Proper Grazing Use, Riparian Areas is provided in this report as an Appendix.

Monitoring of BMPs is important at two levels. On-land compliance monitoring of individual BMPs is necessary, and so is periodic instream monitoring of the watershed. Monitoring of individual compliance with BMPs indicates whether BMPs have been properly installed to achieve what they were designed to do on the site. Monitoring at the watershed level shows whether water quality standards are being fully supported, as the federal Clean Water Act requires. If not, then BMPs need to be modified until water quality condition is such that standards are fully supported.

(3) How is cattle grazing in riparian areas addressed in Idaho water quality policy? Cattle grazing in riparian areas can cause nonpoint source water pollution, and BMPs are designed to control it. Although they are fundamentally important, BMPs are only one part of the water quality policies that address nonpoint source pollution.

Water quality policy is a complex federal-state-local partnership. Numerous agencies and units at all levels of government are responsible for maintaining water quality and the management of the riparian lands that influence water quality.

Idaho has a two-pronged strategy for protection of water quality. The first provides for stream channel protection, dam safety, instream flows, and classification of rivers as natural or recreational, and is primarily managed by the Idaho Department of Water Resources. The second prong is pollution control and is chiefly administered by the Division of Environmental Quality in the Idaho Department of Health and Welfare.

As a state, Idaho must abide by the provisions of the federal Clean Water Act. In 1995, Idaho revised its state water quality law and planning process in order to comply with the Clean Water Act. The new Idaho law (Idaho Code § 39-3601 et seq.) is complex and has not yet been fully implemented in the state. The law requires the Idaho Division of Environmental Quality to identify areas in Idaho having impaired water quality, to improve water quality in those areas, and to prevent water quality in other areas from becoming impaired.

The Idaho Agricultural Pollution Abatement Plan (IDEQ and ISCC 1993) is the state's plan to address nonpoint source pollution from agricultural activities including livestock grazing. The most recent plan focuses on BMP development, implementation, coordination, monitoring, and evaluation. It is a source of information about programs that provide technical assistance, information, and cost-sharing to livestock producers.

Many federal and state agencies have roles in the implementation and enforcement of Idaho's water quality policy. At the federal level, the U.S. Environmental Protection Agency is responsible for ensuring that the state complies with the Clean Water Act. The U.S. Forest Service and the Bureau of Land Management manage more than 60% of Idaho's land and have agreed to implement grazing policies that abide by state water quality law. The Natural Resources Conservation Service in the U.S. Department of Agriculture has broad responsibilities for agricultural and conservation programs on private lands.

At the state level, the Idaho Division of Environmental Quality has the responsibility for general environmental protection and administration of state water quality standards. These are the keys to water quality policy. The Idaho Department of Water Resources is responsible for development of the State Water Plan, water allocation, and stream flow protection. The Idaho Soil Conservation Commission is the agricultural and grazing nonpoint source pollution management agency at the state level. Soil Conservation Districts are the local management units for agricultural nonpoint source pollution activities within their boundaries. The Idaho Department of Lands is responsible for implementing the Idaho Forest Practices Act, which is designed to protect water quality in forest areas. This law requires BMPs for silvicultural activities in forested areas. The Idaho Department of Lands also is responsible for managing the 2.4 million acres of state school trust or endowment lands and the beds and banks of navigable streams and lakes. The Idaho Department of Fish and Game is responsible for collecting information about water quality violations resulting in the loss of fish and wildlife resources.

Other policies also affect cattle grazing in riparian areas. The federal Endangered Species Act affects cattle grazing because several of the 20 species currently listed under the Act in Idaho depend on riparian and aquatic habitat. The U.S. Fish and Wildlife Service, and, for salmon and steelhead, the National Marine Fisheries Service are responsible for protecting and recovering species listed under the Endangered Species Act. On federal lands in Idaho, the U.S. Forest Service and the Bureau of Land Management have adopted an interim strategy called PACFISH for protecting riparian areas adjacent to salmon and steelhead streams. PACFISH has provisions that affect livestock grazing in riparian zones. The U.S. Forest Service also has adopted a similar interim strategy called INFISH for addressing the needs of inland native fish, particularly bull trout and including cutthroat trout. Both of these interim policies establish Riparian Habitat Conservation Areas, or buffer zones, where livestock grazing and other activities must be managed so as to protect fisheries. These interim strategies remain in place on federal lands until the Interior Columbia Basin Ecosystem Management Project is completed in late 1998, which through the Upper Columbia River Basin Environmental Impact Statement (available in draft form for public comment until February 6, 1998) is supposed to replace interim guidelines with standards, or "required actions" that will affect livestock grazing on lands administered by the U.S. Forest Service and Bureau of Land Management.

This page last updated 3/18/98.

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