Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality PART ONE of a Series entitled: The Need for Stream Vegetated Buffers: What Does the Science Say? Janet H. Ellis Montana Audubon Helena, Montana (406) 443-3949 www.mtaudubon.org Prepared for: Montana Department of Environmental Quality EPA/DEQ Wetland Development Grant Helena, Montana June 2008 This document should be cited as: Ellis, J.H. 2008. Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality, Part One, The Need for Stream Vegetated Buffers: What Does the Science Say? Report to Montana Department of Environmental Quality, EPA/DEQ Wetland Development Grant. Montana Audubon, Helena, MT. 24 pp. This report is available at mtaudubon.org Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality Introduction Montana's vast landscape and water resources are critical to the economy, public welfare, and the quality of life of the state's local communities. Each year, development modifies these resources. Ripar- ian areas and their associated wetlands, where water and land come together, are particularly sensitive to changes from development. As a result of increasing pressures, repre- sentatives from local and state governments are discussing ways to protect streams, rivers, and their associated riparian areas from unplanned, sprawl- ing development. One of the main tools available to local governments interested in protecting these resources is to set back structures and protect streamside buffers of native vegetation (hereafter referred to as "building setbacks with vegetative buffers"). In order to use this tool, decision mak- ers and citizens alike must understand the science behind buffer widths. The vegetated buffer is the "work horse" por- tion of this tool because it is the area that filters out pollutants, helps prevent unnatural erosion, works to minimize the impact of floods, sustains the food and habitat offish and wildlife, and more. As a result, relevant scientific studies focus on the vegetated buffer portion of this tool. For more infor- mation on how building setbacks relate to vegetated buffers, see page 3. Protecting water quality is one of the important functions of vegetated buffers. Consequently, this first report in a series summarizes the scientific rec- ommendations underlying the vegetated buffer size needed to protect water quality. Two other reports have been developed in this series on other key ele- ments of stream protection: fisheries and wildlife: • Part II: Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Fish and Aquatic Habitat; and • Part III: Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Wildlife and Wildlife Habitat. Each of these reports is designed to explain the science behind one of the many functions provided by vegetated buffers found along streams. Other topics for this series are currently being considered because building setbacks and vegetated buffers should also consider floodplains and seasonal water levels, stream migration corridors, density of devel- opment adjacent to the riparian corridor, and other factors. Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality Building Setbacks and Vegetated Buffers In order to understand setbacks and buffers, it is important to understand the following con- cepts: Building setbacks or "no build areas" are the distance from a stream's ordinary high water mark to the area where new structures and other developments (such as highly polluting land uses — including roads, parking lots, and waste sites) are allowed. Vegetated Buffers are not an additional area, but rather the portion of the building set- back that is designated to remain undisturbed. These buffers are areas where all native vegeta- tion, rocks, soil, and topography are maintained in their natural state, or enhanced by additional planting of native plants. Lawns should not be considered part of the vegetated buffer. With their shallow roots, lawns are not particularly effective at absorbing and retaining water, espe- cially during heavy rains. Consequently, they do not significantly filter out water pollutants. They can also be a major source of fertilizers and pesti- cides — substances that should be prevented from entering our streams and rivers. How much space should be placed between a building and a vegetated buffer? The building setback should be wide enough to prevent degrada- tion of the vegetated buffer. As an example, most families use the area between their home and the vegetated buffer for lawns, play areas, swing sets, picnic tables, vegetable gardens, landscaping, etc. As a result, the building setback should extend at least 25-50 feet beyond the vegetated buf- fer (Wenger 1999). A smaller distance between a building and a vegetated buffer, such as 10 feet, will most likely guarantee degradation of the vegetated buffer. A greater distance between structures and a vegetated buffer is recommended if the: • River has a history of meandering; the set- backs should ensure that people and homes will not unwittingly be placed too close to the river's edge, in harm's way. • Vegetated buffer is narrower than scientific studies recommend; a deeper building set- back can help protect water quality, fisheries, and aquatic habitat. • Land is sloped and runoff is directed toward the stream (the steeper the slope, the wider a buffer or setback should be) • Land use is intensive (crops, construction, development) • Soils are erodible • Land drains a large area • Aesthetic or economic values need to be pre- served • Wildlife habitat needs to be protected • Landowners desire more privacy Vegetated Buffer Building Setback Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality Vegetated Buffers and Clean Water All Montanans depend upon clean water. Vegetated buffers along streams break down and/ or retain nutrients, salts, sediments, chemical pes- ticides, and organic wastes. Buffers also act like giant sponges to filter and reduce the amount of pollutants that enter streams, groundwater, and — ultimately — drinking water, in runoff originating from sources such as city streets, lawns, construc- tion sites, and agricultural fields. Examples of common vegetated buffer restric- tions include: Minimizing removal of native vegetation; Using native vegetation in plantings and resto- ration; Prohibiting non-native plants (including lawns); Prohibiting the use of pesticides and fertiliz- ers; Avoiding use of heavy equipment that com- pacts soil; and Restricting mowing and managing grazing so as to avoid loss of riparian vegetation. It should be noted that the ability of vegetated buffers to provide adequate water quality protection depends upon the slope, vegetation, floodplains, soils, and other similar factors. The following descriptions explain why these factors influence how effective a vegetated buffer is in protecting water quality: Steep Slopes. From a water quality perspec- tive, the most effective buffers are flat. Scientific research shows that the width of buffers should be increased when slopes are steeper, to allow more opportunity for the buffer to capture pollut- ants (Castelle et al 1994; Fischer et al 2000; Mayer et al 2005; Knutson and Naef 1997; and Wenger 1999). The greater the slope, the faster water flows over the surface. Researchers have noted that very steep slopes cannot effectively remove contaminants, though there is debate over what constitutes a steep slope, with ranges suggested between 10% and 40%. One model suggests that slopes over 25% should not count towards a buffer (Wenger 1999). Vegetation. Natural vegetated buffers are important to water quality, because the longer runoff is detained in a buffer, the fewer pollut- ants will enter the stream. Physically, plants act as a barrier, slowing down water flow, giving sedi- ments and other contaminants time to settle out of runoff, and allowing more water to move into the soil. Plant roots trap sediments and other contaminants in shallow groundwater, take up nutrients, hold banks in place, and prevent ero- sion. Runoff that seeps into shallow groundwater increases groundwater recharge and temporarily stores and slowly discharges precipitation and snowmelt to surface waters over a longer period of time. Although vegetated buffers with woody plant species (trees and shrubs) and native grasses are both effective at trapping pollutants, those with woody plants provide the most effective water quality protection for several reasons. First, by providing a canopy, trees and shrubs reduce the velocity of raindrops and lessen runoff and soil erosion. Trees and shrubs also have longer, more complex root systems, which increase their ability to absorb nutrients and curtail erosion. Overhang- ing branches provide shade that reduces stream temperatures. Litter (leaves and organic debris) from trees and shrubs also increase the infiltra- tion and pollution-absorbing ability of soil. And finally, trees and shrubs provide the most diverse fish and wildlife habitat in Montana, providing cover, nesting sites, and food. Native grasses also have complex root systems — especially compared Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality .■iiiiiiii to the root systems of lawn grass — but they are not as deep-rooted as trees and shrubs. As stated above, lawns — with their shallow roots — are not particularly effective at absorb- ing and retaining water, especially during heavy rains. Consequently, they do not significantly filter out water pollutants. Lawns can also be a major source of fertilizers and pesticides — sub- stances that need to be prevented from entering our streams and rivers. Surfaces without vegetation — including parking lots, compacted or paved roads, and other impervious surfaces — reduce the filtering capability of buffer areas, increase surface ero- sion, and lead to higher and faster storm flows in streams. As a result, restrictions on impervious surfaces should be considered in order to ensure that buffers are effective. Floodplains. Because much pollution can enter streams during storm events caused by snowmelt or heavy rainstorms, protection of a stream or river's floodplain is important. Floodplains covered with native vegetation can significantly remove contaminants, minimize damage from floods, and reduce the amount of unnatural erosion that takes place. For these reasons, it is recommended that vegetated buf- fers encompass the entire floodplain whenever possible (Wenger 1999). This recommendation is particularly important in Montana's valleys, where streams and rivers meander Soils. Different soils have different abilities to filter out sediment and pollutants. Consequently, activities that compact soils or increase erosion (such as vegetation removal) should be avoided in vegetated buffers. The speed with which water and dissolved substances percolate through the soil depends upon the amount of organic mate- rial and the size of the spaces between the grains of soil. As an example, in fine clay soils, pollutants may take months or years to move into streams and groundwater. In porous soils (e.g. with more sand and gravel), pollutants can flow almost directly into streams or groundwater. Contaminants Impacting Water Quality Many of the substances covered in this report can degrade water quality. Vegetated stream buf- fers are an important tool that local governments can use to filter out these pollutants. Tables II and III summarize the information from scientific studies that tested how stream vegetated buffers filtered out the following contaminants (which are listed in alphabetical order, and not in order of importance): Ammonium (NH4) is a form of nitrogen (see Nitrogen below) found in human and animal waste (hence in sewage and septic field leakage) and in some fertilizers. It is toxic to fish and many other Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality Lawns — with their shallow roots — do not significantly filter out water pollutants. They can also be a source of fertilizers and pesticides, substances that should not enter streams and rivers. Montana Dept. of Natural Resources and Conservation photo library. forms of stream life. Like all forms of nitrogen, ammonia can contribute to eutrophication (over- fertilization) of lakes, wetlands, and slow-moving streams {see Nutrients below). Fecal coliform bacteria are found in the fecal material of humans or other animals and are used as an indicator of the likely presence of bacteria and viruses that cause a wide range of diseases. Sources of such bacteria and viruses include leak- ing sewer pipes, sewer overflows, failing septic systems, and areas where concentrations of ani- mals are found, such as animal feedlots, city parks frequented by dogs, and areas with colonial nest- ing birds. The higher the levels of fecal coliform bacteria in water the greater the risk to human health because of the many waterborne patho- genic diseases associated with bodily wastes. Heavy metals, such as lead, mercury, cad- mium, copper, and zinc, occur naturally in streams and soils. However, many human activi- ties increase the movement of these substances from land into water, raising the concentration of these metals to levels that are toxic to aquatic life. At very high levels, such metals may quickly kill aquatic life. Even at fairly low levels, metals may gradually accumulate in the liver or kidneys of animals, causing failure of these organs. The main sources of these contaminants are industrial and consumer waste, including power plant and other industrial emissions, old mining operations, run- Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality off from roads and parking areas, and fertilizers. Nitrogen (N) is an essential nutrient for all life. Under natural conditions it is often in short supply, limiting plant growth. However, many kinds of human activity increase availability of nitrogen, stimulating growth of plants. In water, excess nitrogen is a pollutant that can cause eutrophication (over-fertilization) (see Nutri- ents below) in surface water and contamination of groundwater. As a drinking water pollutant, nitrogen is particularly dangerous for infants. Streams receive nitrogen from sources such as fertilizers, animal wastes, leaking sewer lines and septic systems, and runoff from highways. The U.S. Environmental Protection Agency considers nitrogen one of the "top stressors in aquatic eco- systems" (Mayer, et al 2005). Nitrogen occurs in many forms, including nitrates, nitrites, ammo- nium, and particulate nitrogen. Nitrates (NO3) and Nitrites (NO2) are forms of nitrogen that occur in fertilizers, animal wastes, septic tanks, municipal sewage treatment systems, and decaying plants (see Nitrogen above). Nitrates/ nitrites can move quickly through the soil and into groundwater and surface water. However, nitrate/ nitrite levels in shallow groundwater can be reduced before reaching surface water in two main ways: (1) uptake by the roots of plants in vegetated buffers, or (2) use by bacteria that live in water-saturated soils which convert nitrates/nitrites to harmless nitrogen gas (a process called denitrification). Nutrients are substances that are essential to life and include certain forms of nitrogen (see above) and phosphorus (see below). Increases in availability of nutrients may stimulate addi- tional growth of plants. In water, excess nutrients increase the rate of eutrophication of lakes and slow-moving streams. Eutrophication can stimu- late abundant plant growth in water bodies, which can lead to toxic algae blooms, excessive growth of nuisance aquatic plants, the depletion of oxy- gen in water, and — ultimately — the death of fish and other organisms. Hence at excessive levels, nutrients are considered water pollutants. Pesticides, including both herbicides and insecticides, are designed to be toxic. The main sources for these chemicals include spraying of crops, weed-infested rangelands, lawns, and orna- mental plants. At high enough concentrations in streams, pesticides may kill stream life outright, or weaken organisms so they die more readily from 'natural causes.' Pesticides also pose a risk to human health, especially those that biomagnify in the food chain. Biomagnification refers to the process where certain substances increase in con- centration as they move from one link in the food chain to another. Phosphorus (P) is an essential nutrient for plant growth that is found naturally in soils and streams, but exists in much higher levels in fertiliz- ers and in human and other animal waste. It enters streams in waste water or in runoff polluted with fertilizers or animal wastes, including from leaking sewer pipes or septic drain fields. Stream veg- etated buffers are typically effective at short-term control of phosphorus that is bound to sediment particles — they are less effective at (1) filtering out phosphorus that is dissolved in water, or (2) pro- viding long-term storage of phosphorus (Wenger 1999). Increased levels of phosphorus can contrib- ute to eutrophication (see Nutrients above). Sediments are a common type of pollutant found in streams and rivers. Sediments come from a variety of sources, including natural and human-driven stream bank erosion, agricultural fields, exposed earth at construction sites and on dirt roads, and other activities that remove vegetation and expose soil. Excess sediment has numerous impacts, including degrading munici- pal water supplies and, as a result, increasing water Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality treatment costs and/or posing a threat to human heath when treatment is made less effective. It can also degrade habitat for fish and the aquatic life that they eat and can clog drainage ditches, stream channels, water intakes, and reservoirs. About This Report — Methods Used This report summarizes the recommen- dations of 77 scientific studies that tested how various stream vegetated buffers protected water quality (see Appendix I). These scientific studies were reviewed by the authors of 5 review publi- cations. Please note that the information in this report was taken from the text and tables of 5 review publications — and that the original stud- ies were not reviewed in this report. The 5 review publications are: • Castelle, A.J., A. W. Johnson, and C. Conolly. 1994. Wetland and stream buffer size require- ments — a review. J. Environ. Qual. 23: 878-882. • Fischer, R.A., CO. Martin, and J.C. Fischen- ich. 2000. Improving riparian buffer strips and corridors for water quality and wildlife. Inter- national Conference on Riparian Ecology and Management in Multi-Land Use Watersheds. American Water Resources Association. August 2000. 7 pp. • Knutson, K.L. and V.L. Naef 1997. Manage- ment recommendations for Washington's priority habitats: riparian. Wash. Dept. Fish and Wildlife, Olympia, WA. 181 pp. • Mayer, RM., Steven K. Reynolds, Jr., Timo- thy J. Caneld. 2005. Riparian buffer width, vegetated cover, and nitrogen removal effec- tiveness: a review of current science and regulations. U.S. Environmental Protection Agency, EPA/600/R-05/118, National Risk Man- agement Research Laboratory, Ada, OK. 28 pp. • Wenger, S.J. 1999. A review of the scientific literature on riparian buffer width, extent and vegetation. Athens: Institute of Ecology Office for Public Service and Outreach, University of Georgia. 59 pp. Appendbc ff contains the original references cited in the 5 review publications described above, allowing individuals using Appendix I to see the full title of all original references, as well as have sufficient information to access all references, if necessary. Summary of Scientific Recommendations All Montanans depend upon clean water — and streamsidevegetatedbuffers play an important role in water quality protection. These areas break down and hold nutrients, chemical pesticides, salts, sediments, and organic wastes. They reduce the amount of pollution that enters streams, riv- ers, groundwater, and — ultimately — drinking Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality water, in runoff originating from sources such as city streets, leaking sewer lines and septic sys- tems, lawns, construction sites, and agricultural fields. As a result: In order to protect the water quality of streams, scientific studies generally recommend that at least a loo-foot (30-meter) vegetated buf- fer be maintained. Steeper slopes and other local factors may require larger vegetated buffers. A minimum of a 50-foot (15-meter) buffer may be suf- ficient to protect certain aspects of water quality. However, for significant removal of nitrates, sedi- ments, and pathogenic bacteria, at least 100 feet is recommended. This recommendation is drawn from the con- clusions of the 5 publications that reviewed a total of 77 separate scientific studies on water quality and stream vegetated buffers. Specific conclusions and recommendations by the 5 review publication authors are quoted in Table I. This conclusion is also supported by the State of Montana's Nonpoint Source Management Plan, which was approved by the U.S. Environmental Pro- tection Agency (EPA) in July 2007. It states that a "buffer of at least 100 feet is recommended for water quality protection. . . . Minimum widths for buffers should be 50 feet for low order headwaters streams, with expansion to as much as 200 feet or more for larger streams." Montana's Nonpoint Source Man- agement Plan identifies locally-adopted water body setbacks as important "Best Management Practices" to protect and improve water quality from nonpoint source pollution. Nonpoint sources of pollution in urban areas include parking lots, streets, and roads where stormwater picks up oils, grease, metals, dirt. Table 1. A summary of the specific conclusions and recommendations of 5 review articles on vegetated buffer size and water quality protection. All authors emphasized that water quality protection depends on the slopes, soils, vegeta- tion, floodplains, and similar factors. Castelleetah994 "Based on existing literature, buffers necessary to protect wetlands and streams should be a mini- mum of 15 to 30 meters in width" (50-100 feet). Buffers less than 10 meters (33 feet) "provide little protection of aquatic resources under most circumstances." Fischer et al 2000 Concluded that "most buffer width recommendations for improving water quality tend to be between 10 and 30 m" (33-100 feet). Knutson and Naef 1997 Concluded that scientific studies indicated that vegetated buffers to protect water quality should be between 24 and 42 meters (78-138 feet). Mayer etal 2005 Concluded that "wider buffers (>50 m) [167 feet] more consistently removed significant portions of nitrogen entering a riparian zone." [W]hile some narrow buffers (1-15 m) [3-50 feet] removed significant proportions of nitrogen, nar- row buffers actually contributed to nitrogen loads in riparian zones in some cases." Wengeri999 To protect water quality overall, "a 100 ft [30 meter] fixed-width riparian buffer is recommended for local governments that find it impractical to administer a variable-width buffer." For long-term sediment control and short-term phosphorus control, a "30 m (100 ft) buffer is suf- ficiently wide to trap sediments under most circumstances." For nitrogen control, in "most cases 30 m (100 ft) buffers should provide good control, and 15 m (50 ft) should be sufficient under many conditions." For pesticide and heavy metal control, "the width is unclearfrom the existing research," with 15 meters (50 feet) seen as a bare minimum, and 50 meters (164 feet) shown to filter out much of two specific pesticides. Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality salts, and other toxic materials. In areas where crops are grown or in areas with landscaping (including grassy areas of residential lawns and city parks), irrigation and rainfall can carry soil, pesticides, fer- tilizers, herbicides, and insecticides to surface water and groundwater (Montana Department of Envi- ronmental Quality, 2007). Several additional recommendations are worth noting: • "The greater the minimum buffer width, the greater the safety margin in terms of water quality and habitat protection." (Wenger 1999) • "Removal of riparian vegetation, drainage of wetlands and development of floodplains leads to larger magnitude floods that cause greater damage to property." (Wenger 1999) • "To provide maximum protection from floods and maximum storage of flood waters, a buffer should include the entire floodplain. Short of this, the buffer should be as wide as possible and include all adjacent wetlands." (Wenger 1999) • "Riparian buffers are especially important along the smaller headwater streams which make up the majority of stream miles in any basin." (Wenger 1999) • "It is very important that buffers be continuous along streams. Gaps, crossings, or other breaks in the riparian buffer allow direct access of surface flow to the stream, compromising the effectiveness of the system." (Wenger 1999) • "[E]xtensive experimental support for buf- fer zones fr.^j.-.-.- 1 ■ 1 Author of Original Meters Feet Scientific Studv Name of Review Article Nutrient removal — using the multi- species riparian buffer strip system described by the authors 20 66 Schultzet al 1995 Knutson and Naef 1997 Nutrient reduction — suggested dis- tance to protect water quality 36 118 Young etah98o Knutson and Naef 1997; Wengeri999 Nutrient reduction — buffers needed in forested riparian areas 30 100 Terrell and Perfetti 1989 Knutson and Naef 1997 Nutrient reduction — buffers needed in herbaceous or cropland riparian areas 183 600 Terrell and Perfetti 1989 Knutson and Naef 1997 Nutrient reduction — improve or pro- tect water quality >10 >33 Corleyetal 1999 Fischer etal 2000 Nutrient reduction — improve or pro- tect water quality from logging >30 >ioo Lynch et al 1985 Knutson and Naef 1997; Castelle et al 1994; Fischer et al 2000 Nutrient reduction — improve or pro- tect water quality >18 >6o Lynch etal 1985 Fischer etal 2000 Nutrient reduction — improve or pro- tect water quality >15 >50 Woodard and Rock 1995 Fischer etal 2000 Nutrient reduction — improve or pro- tect water quality >25 >82 Young et al 1980 Fischer et al 2000 Nutrient reduction — minimum buffer size recommended 10 33 Petersen et al 1992 Knutson and Naef 1997 Nutrient reduction 4 13 Doyle eta 11977 Knutson and Naef 1997; Castelle et al 1994; Fischer etal 2000 Nutrient reduction 16 52 Jacobs and Gilliam 1985 Knutson and Naef 1997 Nutrient reduction 30-43 100-141 Jones etal 1988 Knutson and Naef 1997 Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality FILTER POLLUTANTS— Animal Waste* "Depends on slope, soils, etc. ^^^^^^ m Meters Feet Author of Original^^" Scientific Study Name of Review Article 78% ammonium reduction from sur- face water 50 164 PeterjohnandCorrell 1984 Wenger 1999 71% ammonium reduction from sur- face water 21 70 Young et al 1980 Wenger 1999 20-50% ammonium reduction 6-18 20-50 Daniels and Gilliam 1996 Wenger 1999 Fecal coliform removed 30 100 Grismeri98i Knutson and Naef 1997 Fecal coliform removed 30-43 100-141 Jones etal 1988 Knutson and Naef 1997 Fecal coliform removed 30 100 Lynch et al 1985 Knutson and Naef 1997 87% of fecal coliform removed 60 197 Karr and Schlosser 1977 Wenger 1999 34-74% of fecal coliform removed 9 30 Coyne etal 1995 Wenger 1999 Feedtot waste — distance needed to filter confined animal waste 183 600 Terrell and Perfetti 1989 Knutson and Naef 1997 80% of feedlot waste removed 91-262 300-860 Vanderholm and Dickey 1978 Castelle et al 1994 92% of suspended sediment removed from feedlot waste 24 80 Young etal 1980 Castelle etal 1994 33% of suspended sediment removed from feedlot waste 23 75 Schellinger and Clausen 1992 Castelle etal 1994 ^^^^ ■ ■ ■ FILTER POLLUTANTS— Nitrogen in various forms'* ^^^^ ^ ^^ 1 Author of Original Scientific Study 1 J —i me of Review Article NITRATES IN SURFACE RUNOFF ^^^^^^^^^^^| Nearly 100%' nitrate reduction 20-30 66-100 Fennesy and Cronk 1997 Wenger 1999 Nitrates removed to meet drinking water standards 30 100 Johnson and Ryba 1992 Knutson and Naef 1997 99% nitrate reduction in forested buf- fer 10 33 Xu et al 1992 Castelle et al 1994 79% nitrate reduction In forest buffer 70-85 230-279 PeterjohnandCorrell 1984 Wenger 1999; Mayer et al 2005 78% nitrate reduction In forest buffer 30 98 Lynch et al 1985 Mayer et al 2005 27-57% nitrate reduction In grassland buffer 5-9 15-30 Dillaha etal 1989 Mayer et al 2005 20-50% nitrate reduction in grassland buffer 8-16 26-53 Vought etal 1994 Wenger 1999 16-76% nitrate reduction in grassland buffer 26 85 Schwer and Clausen 1989 Mayer etal 2005 13 Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality 1 ^^ 1 Author of Original ^ Ifiiie of Review Article n 12-74% nitrate reduction through wetland vegetation 20 66 BriJsch and Nilsson 1993 Mayer etal 2005 8% nitrate reduction in grassland buf- fer 27 89 Young et al 1980 Mayer et al 2005 Nitrates increased across buffer 21 70 Young etal 1980 Wengeri999 Nitrates increased in grassland buffer 5-9 15-30 Dillahaetali988 Wenger 1999; Mayer et al 2005 NITRATES IN SHALLOW GROUNDWATER m^^^ ioo% nitrate reduction 30 98 Pinay and Decamps 1988 Mayer et al 2005 ioo% nitrate reduction 30 98 Pinay et al 1993 Mayer et al 2005 ioo% nitrate reduction 40 131 Puckett et al. 2002 Mayer etal 2005 ioo% nitrate reduction 10-20 33-66 Vought et al 1994 Wenger 1999 99% nitrate reduction 50 164 Jacobs and Gilliam 1985 Mayer etal 2005 99% nitrate reduction 10 33 Cey etal 1999 Mayer etal 2005 98% nitrate reduction 100 328 Prach and Rauch 1992 Mayer et al 2005 97-99% nitrate reduction in grass- forest area 33-66 108-216 Vidon and Hill 2004 Mayer et al 2005 97% nitrate reduction 165 541 Hill etal. 2000 Mayer etal 2005 96% nitrate reduction in clay soils 1 3 Burns and Nguyen 2002 Mayer etal 2005 96% nitrate reduction 15 49 Hubbard and Sheridan 1989 Mayer et al 2005 95% nitrate reduction 200 656 Fustec etal 1991 Mayer etal 2005 95% nitrate reduction 60 197 Jordan et al 1993 Wenger 1999; Mayer et al 2005 94-98% nitrate reduction in forest area 204-220 669-721 Vidon and Hill 2004 Mayer etal 2005 94% nitrate reduction 50-60 160-200 Lowrance 1992 Wenger 1999; Mayer et al 2005 94% nitrate reduction 85 280 Peterjohn and Correll 1984 Mayer et al 2005 91% nitrate reduction 6 20 Borinand Bigon 2002 Mayer etal 2005 91% nitrate reduction 70 230 Hubbard and Lowrance 1997 Mayer etal 2005 90-99% nitrate reduction 50 164 Peterjohn and Correll' 1984 Wenger 1999 89% nitrate reduction 16 52 Haycock and Burt 1993 Mayer etal 2005 14 Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality 1 Meters ■' I^^J Author of Original ^H Scientific Study ^| " ^e of Review Article NITRATES IN SHALLOW GROUNDWATER (continued) J _ F 84-99% nitrate reduction 16-20 52-66 Haycock and Pinayi993 Wenger 1999; Mayer et al 2005 84-98% nitrate reduction 25-50 82-164 Hefting and de Klein 1998 Mayer et al 2005 84-97% nitrate reduction 6-15 19-50 Simmons etali992 Mayer etal 2005 83% nitrate reduction 55 180 Lowranceetali984 Mayer etal 2005 83% nitrate reduction 20 66 Schultzet al 1995 Mayer et al 2005 82-99% nitrate reduction 10 33 Schoonover and Williard 2003 Mayer etal 2005 82-95% nitrates reduction 16-39 52-128 Osborne and Kovacic 1993 Wenger 1999; Mayer et al 2005 80-100% nitrate reduction 50-70 164-230 IVlartin et al 1999 Mayer et al 2005 80-81% nitrate reduction 20-28 66-92 Mander et al 1997 Wenger 1999 78% nitrate reduction 30 100 Hubbard 1997 Wenger 1999 78% nitrate reduction 38 125 Vellidisetal.2003 Mayer etal 2005 64-100% nitrate reduction 100-200 328-656 Spruill2004 Mayer etal 2005 60-99% nitrate reduction in grassland area 25-30 82-98 Vidon and Hill 2004 Mayer et al 2005 59-94% nitrate reduction^ 31 102 Hanson et al 1994 Wenger 1999; Mayer et al 2005 58-96% nitrate reduction 10-50 33-164 Hefting etal 2003 Mayer etal 2005 52-76% nitrate reduction 5 16 Clausen etal. 2000 Mayer etal 2005 NITROGEN ^^^B Nitrogen removed 30 100 Muscuttetali993 Wenger 1999 90-99% nitrogen reduction 5-9 15-30 Madison etal 1992 Castelle et al 1994 89% nitrogen reduction 19 62 Shisleretal 1987 Castelle et al 1994; Fischer etal 2000 86% nitrogen reduction in surface water 50 164 Peterjohn and Correll ' 1984 Wenger 1999 67-74% nitrogen reduction 5-9 15-30 Dillaha etal 1988 Wenger 1999 67% nitrogen reduction 21 70 Young et al 1980 Wenger 1999 54-73% nitrogen reduction 5-9 15-30 Dillaha etal 1989 Castelle et al 1994; Wenger 1999 38% nitrogen reduction in grassland 91 299 Zirschky etal 1989 Mayer etal 2005 28-51% nitrogen reduction in grass/ forest 8-15 25-50 Schmitt et al 1999 Mayer etal 2005 17-51% nitrogen reduction 5-9 15-30 Magette etal 1987 Wenger 1999 15 Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality 1 I^^J AutKior of Original Scientific Study ^ Ifiiie of Review Articlfe"^" r meters NITROGEN (continued) , ^^^^H. .» • — »-^ - ^ m Buffer zones less than 10 meters (33 feet) lack extensive experimental support >10 >33 Hickley and Doran 2004 Mayer et al 2005 Nitrogen increased or reduced by 48% 5-9 15-30 Magette et al 1989 Wenger 1999; Mayer et al 2005 Nitrogen increased in groundwater 50 164 Peterjohn and Correll ' 1984 Wenger 1999 FILTER POLLUTANTS— Pesticides and Heavy Met Pesticides — buffering distance for sedi- ment with pesticides — ungrazed buffers 61 Author of Original Scientific Study Terrell and Perfetti 1989 me of Review Article Knutson and Naef 1997 Pesticides — various types — almost 100% over 3 years 50 164 Lowrance et ah997 Wenger 1999 Pesticides — various types — 8-100% reduction 66 Arora et al 1996 Wenger 1999 Pesticides — various types — 10-40% reduction 12-60 40-60 Hatfield et al 1995 Wenger 1999 Lead removal 61 Horner and Mar 1982 Castelle et al 1994 FILTER POLLUTANTS— Phosphorus|^j 'Depends on slope, soils, etc. ^^^^^H ^^^^^^^^^^H 1 1 1 ^ ^m Meters Feet Author of Original Scientific Study Name of Review Article 100% phosphorus reduction 61 200 Horner and Mar 1982 Castelle etal 1994 80% phosphorus reduction 19 62 Shisleretal 1987 Castelle etal 1994; etal 2000 Fischer 73-84% phosphorus reduction — in surface water 50 164 Peterjohn and Correll 1984 Wenger 1999 67-81% phosphorus reduction in short-term study 20-28 66-92 Manderetali997 Wenger 1999 83% phosphorus reduction in short- term study 21-27 70-90 Young etal 1980 Wenger 1999 66-95% phosphorus reduction in surface water in short-term study 8-16 26-53 Vought et al 1994 Wenger 1999 61-79% phosphorus reduction in short-term study 5-9 15-30 Dillaha etal 1989 Castelle et al 1994; 1999 Wenger 58-72% phosphorus reduction in short-term study 5-9 15-30 Dillaha etal 1988 Wenger 1999 41-53% phosphorus reduction in short-term study 5-9 15-30 Magette etal 1987 Wenger 1999 18-46% phosphorus reduction in short-term study 5-9 15-30 Magette et al 1989 Wenger 1999 16 Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality FILTER POLLUTANTS— Sediments* 'Depends on slope, soils, etc. ^^g r 9 Meters Feet Scientific Study Name of Review Article Sediment removal — adequate buf- fer for cropland, animal waste across ungrazed buffer, and for pesticides 61 200 Terrell and Perfetti 1989 Knutson and Naef 1997 Sediment removal 30 100 Moring et al 1982 Knutson and Naef 1997 Sediment removal — to prevent impacts in logged forest 30 100 Davies and Nelson 1994 Wengeri999 Sediment removal — based on multi- year studies 30 100 Cooper etal 1988 Wengeri999 Sediment removal — minimum needed 30 100 Erman etal 1977 Wenger 1999 Effective sediment removal — most effective width of vegetated buffers 25 82 Desbonnet et al 1994 Wenger 1999 Effective sediment removal — adequate buffer for logging practices on steep slopes — buffer measured from edge of floodplain 61 200 Broderson 1973 Knutson and Naef 1997; Castelle etal 1994 Effective sediment removal — buffer strip width to control non-channelized sediment flow 60-91 200-300 Belt et al 1992 Knutson and Naef 1997 99% sediment reduction in short-term study (i rainfall) 9 30 Coyne et al 1995 Wenger 1999 90-94% sediment reduction in short- term study 19-60 62-197 PeterjohnandCorrell 1984 Wenger 1999 90% sediment reduction at 2% grade 30 100 Johnson and Ryba 1992 Knutson and Naef 1997 85% sediment reduction 9 30 Ghaffarzadeh et al 1992 Castelle etal 1994 80% sediment reduction 61 200 Horner and IVlar 1982 Castelle etal 1994 76-95% sediment removal in short- term study 5-9 15-30 Dillahaetali988 Wenger 1999 75-80% sediment reduction from log- ging activity 30 100 Lynch etal 1985 Knutson and Naef 1997; Castelle et al 1994; Fischer et al 2000 75-80% sediment reduction from stormwater in logged areas; more effec- tive where runoff is in sheets; less effective where surface flows are channelized 30 100 Johnson and Ryba 1992 Knutson and Naef 1997 75% sediment reduction 30-38 100-125 Karr and Schlosser 1977 Knutson and Naef 1997 70-84% sediment reduction 5-9 15-30 Dillaha etal 1989 Castelle et al 1994; Wenger 1999 66-93% sediment reduction in short- term study 21-27 70-90 Young etal 1980 Castelle et al 1994; Wenger 1999; Fischer et al 2000 66-82% sediment reduction in short- term study 5-9 15-30 Magetteet a 1 1989 Wenger 1999 50% sediment reduction — based on muti-year studies 100 328 Lowranceetali988 Wenger 1999 50% sediment reduction 88 289 Gilliam and Skaggs 1988 Knutson and Naef 1997 17 Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality 1 NOTE: Wenger (1999) refers to two articles written by Peter- john and Correll: one from 1984 and one from 1985. It appears that the article he cited was Peterjohn and Correll 1984. 2 NOTE: Wenger (1999) reported a 94% reduction in nitrates for this study while Mayer et al (2005) reported a 59% reduction. Both figures are presented. Appendix II References Cited All scientific studies that appear in this report are cited below: Arora, K., S. K. Mickelson, J. L. Baker, D. P. Tierney, C. J. Peters. 1996. Herbicide retention by vegetative buffer strips from runoff under natural rainfall. Transactions of the ASAE. 2155-2162. (from Wenger 1999) Belt, G. H., J. O'Laughlin, and T. Merrill. 1992. Design of forest riparian buffer strips for the protection of water quality: analysis of scientific literature. Id. For., Wildl. and Range Policy Anal. Group. Rep. No. 8. 35 pp. (from Knutson and Naef 1997) Borin, M., and E. Bigon. 2002. Abatement of NO^N con- centration in agricultural waters by narrow buffer strips. Environmental Pollution 117:165-168. (from Mayer et al 2005) Broderson, J. M. 1973. Sizing buffer strips to maintain water quality. M.S. Thesis, Univ. Washington, Seat- tle. 86 pp. (from Knutson and Naef 1997; Castelle et al 1994) Briisch, W, and B. Nilsson. 1993. Nitrate transformation and water movement in a wetland area. Hydrobio- logia 251:103-111. (from Mayer et al 2005) Burns, D.A., and L. Nguyen. 2002. Nitrate movement and removal along a shallow groundwater flow path in a riparian wetland within a sheep-grazed pastoral catchment: results of a tracer study. New Zealand Journal of Marine and Freshwater Research 36:371-385. (from Mayer et al 2005) Castelle, A.J., A. W Johnson, and C. ConoUy. 1994. Wetland and stream buffer size requirements — a review. J. Environ. Qual. 23: 878-882. Cey, E.E., D.L. Rudolph, R. Aravena, and G. Parkin. 1999. Role of the riparian zone in controlling the distri- bution and fate of agricultural nitrogen near a small stream in southern Ontario. Journal of Contami- nant Hydrology 37:45-67. (from Mayer et al 2005) Clausen, J.C., K. Guillard, CM. Sigmund, and K.M. Dors. 2000. Water quality changes from riparian buffer restoration in Connecticut. Journal of Environmen- tal Quality 29:1751-1761. (from Mayer et al 2005) Cooper, J. R., J. W Gilliam, R. B. Daniels and W R Robarge. 1987. Riparian areas as filters for agricul- tural sediment. Soil Science Society of America Journal 51:416-420. (from Wenger, 1999) 18 Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality Corley, C. J., G. W. Frasier, M. J. Trlica, E M. Smith, and E. M. Taylor, 1999. Technical Note: Nitrogen and phosphorus in runoff from 2 montane ripar- ian communities. Journal of Range Management 52:600-605. (from Eischer et al 2000) Coyne, M. S., R. A. Gilfillen, R. W. Rhodes and R. L., Blevins. 1995. Soil and fecal coliform trapping by grass filter strips during simulated rain. Journal of Soil and Water Conservation 5o(4):405-4o8. (from Wenger 1999) Daniels, R. B. and J. W. Gilliam. 1996. Sediment and chemical load reduction by grass and riparian filters. Soil Science Society of America Journal 60:246-251. (from Wenger 1999) Davies, P. E. and M. Nelson. 1994. Relationships between riparian buffer widths and the effects of logging on stream habitat, invertebrate community compo- sition and fish abundance. Australian Journal of Marine and Ereshwater Resources 45: 1289-1305. (from Wenger 1999) Desbonnet, A., P. Pogue, V. Lee and N. Wolf. 1994. Veg- etated Buffers in the Coastal Zone: A Summary Review and Bibliography. Providence: University of Rhode Island, (from Wenger 1999) Dillaha, T. A., J. H. Sherrard, D. Lee, S. Mostaghimi, V.O. Shanholtz. 1988. Evaluation of vegetative filter strips as a best management practice for feed lots. Journal of the Water Pollution Control Eederation 6o(7):i23i-i238. (from Wenger 1999; Mayer et al 2005) Dillaha, T.A., R.B. Reneau, S. Mostagnumi, and D. Lee. 1989. Vegetative filter strips for agricultural non- point source pollution control Trans. Amer. Soc. Agric. Engin. 32:513-519. (from Castelle et al 1994; Wenger 1999; Eischer et al 2000; Mayer et al 2005) Doyle, R. C, C. G. Stanton, and D. C. Wolf 1977. Effective- ness of forest and grass buffer strips in improving the water quality of manure polluted runoff. ASAE Paper No. 77-2501. St. Joseph, Mich, (from Knutson and Naef 1997; Castelle et al 1994; Eischer et al 2000) Erman, D. C, J. D. Newbold, and K. R. Ruby. 1977. Eval- uation of streamside bufferstrips for protecting aquatic organisms. Water Resour. Cent. Contr. 165, Univ. California, Davis. 48 pp. (from Knutson and Naef 1997) Eennessy, M. S. and J. K. Cronk. 1997. The effectiveness and restoration potential of riparian ecotones for the management of nonpoint source pollution, particularly nitrate. Critical Reviews in Environ- mental Science and Technology 27(4):285-3i7. (from Wenger 1999) Eischer, R.A., CO. Martin, and J.C. Eischenich. 2000. Improving riparian buffer strips and corridors for water quality and wildlife. International Conference on Riparian Ecology and management in Multi- Land Use Watersheds. American Water Resources Association. August 2000. 7 pp. Eustec, E., A. Mariotti, X. Grillo, and J. Sajus. 1991. Nitrate removal by denitrification in alluvial groundwater: role of a former channel. Journal of Hydrology 123:337-354- (from Mayer et al 2005) Ghaffarzadeh, M., C.A. Robinson, and R.M. Cruse. 1992. Vegetative filter strip effects on sediment deposition from overland flow. P. 324. In Agronomy abstracts. ASA, Madison, WI. (from Castelle et al 1994) GiUiam, J. W, and R. W Skaggs. 1988. Natural buffer areas and drainage control to remove pollutants from agricultural drainage waters. Pages 145-148 in J. A. Kusler, M. Quammen, and G. Brooks, eds. Proc. of the national wetland symposium: mitiga- tion of impacts and losses. U.S. Eish and Wildl. Serv., U.S. Env. Prof. Agency, and U.S. Army Corps Eng. ASWM Tech. Rep. 3. (from Knutson and Naef 1997) Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality Grismer, M. E. 1981. Evaluating dairy waste management systems influence on fecal coliform concentration in runoff. M.S. Thesis, Oregon State Univ., Corval- lis. 104 pp. (from Knutson and Naef 1997) Hanson, G. C., P. M. Groffman and A. J. Gold. 1994. Den- itrification in riparian wetlands receiving high and low groundwater nitrate inputs. Journal of Envi- ronmental Quality 23:917-922. (from Wenger 1999; Mayer et al 2005) Hatfield, J. L., S. K. Mickelson, J. L. Baker, K. Arora, D. P. Tierney, and C. J. Peter. 1995. Buffer strips: Land- scape modification to reduce off-site herbicide movement. In: Clean Water, Clean Environment, 21st Century : Team Agriculture, Working to Protect Water Resources, Vol. 1. St. Joseph, MI: American Society of Agricultural Engineers, (from Wenger 1999) Haycock, N.E., and T.P Burt. 1993. Role of floodplain sediments in reducing the nitrate concentration of subsurface run-off: a case study in the Cotswolds, UK. Hydrological Processes 7:287-295. (from Mayer et al 2005) Haycock, N.E., and G. Pinay. 1993. Groundwater nitrate dynamics in grass and poplar vegetated riparian buffer strips during the winter. Journal of Envi- ronmental Quality 22:273-278. (from Wenger 1999; Mayer et al 2005) Hefting, M.M., R. Bobbink, and H. de Caluwe. 2003. Nitrous oxide emission and denitrification in chronically nitrate-loaded riparian buffer zones. Journal of Environmental Quality 32:1194-1203. (from Mayer et al 2005) Hefting, M.M., and J.J.M. de Klein. 1998. Nitrogen removal in buffer strips along a lowland stream in the Netherlands: a pilot study. Environmental Pol- lution 102, Si:52i-526. (from Mayer et al 2005) Hickey, M.B.C., and B. Doran. 2004. A review of the efficiency of buffer strips for the maintenance and enhancement of riparian ecosystems. Water Qual- ity Research Journal of Canada 39:311-317. (from Mayer et al 2005) Hill, A.R., K.J. Devito, S. Campagnolo, and K. Sanmu- gadas. 2000. Subsurface denitrification in a forest riparian zone: Interactions between hydrology and supplies of nitrate and organic carbon. Biogeo- chemistry 51:193-223. (from Mayer et al 2005) Horner, R.R., and B.W Mar. 1982. Guide for water qual- ity impact assessment of highway operations and maintenance. Rep. WA-RD-39.14. Washington Dep. Of Trans., Olympia, WA. (from Castelle et al 1994) Hubbard, R. K. 1997. Riparian buffer systems for manag- ing animal waste. Proceedings of the Southeastern Sustainable Animal Waste Workshop. Athens, GA: University of Georgia, (from Wenger 1999) Hubbard, R.K., and R. Lowrance. 1997. Assessment of forest management effects on nitrate removal by riparian buffer systems. Transactions of the Ameri- can Society of Agricultural Engineers 40:383-391. (from Mayer et al 2005) Hubbard, R.K., and J.M. Sheridan. 1989. Nitrate move- ment to groundwater in the southeastern Coastal Plain. Journal of Soil and Water Conservation 44:20-27. (from Mayer et al 2005) Jacobs, T. C, and J. W Gilliam. 1985. Riparian losses of nitrate from agricultural drainage waters. J. Envi- ron. Quality 14:472-478. (from Knutson and Naef 1997; Mayer et al 2005) Johnson, A. W, and D. M. Ryba. 1992. A literature review of recommended buffer widths to maintain vari- ous functions of stream riparian areas. Prepared for King Co. Surface Water Manage. Div., Aquatic Resour. Consult., Seattle. 28 pp. (from Knutson and Naef 1997) Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality Jones, J. J., J. P. Lortie, and U. D. Pierce, Jr. 1988. The identification and management of significant fish and wildlife resources in southern coastal Maine. Maine Dept. Inland Fish, and WildL, Augusta. 140 pp. (from Knutson and Naef 1997) Jordan, T. E., D. L. Correll and D. E. Weller. 1993. Nutri- ent interception by a riparian forest receiving inputs from adjacent cropland. Journal of Environ- mental Quality 22:467-473. (Wenger 1999; Mayer et al 2005) Karr, J. R., and I. J. Schlosser. 1977. Impact of nearstream vegetation and stream morphology on water qual- ity and stream biota. U.S. Environ. Prof. Agency, Environ. Res. Lab., Off. of Res. and Dev. Athens, Ga. EPA-600/3-77-097. (from Knutson and Naef 1997; Wenger 1999) Knutson, K.L. and V.L. Naef 1997. Management recom- mendations for Washington's priority habitats: riparian. Wash. Dept. Fish and Wildlife, Olympia, WA. 181 pp. Lowrance, R. R. 1992. Groundwater nitrate and denitrifi- cation in a Coastal Plain riparian forest. Journal of Environmental Quality 21:401-405. (from Wenger 1999; Mayer et al 2005) Lowrance, R. R., S. Mclntyre and C. Lance. 1988. Erosion and deposition in a field/forest system estimated using cesium-137 activity. Journal of Soil and Water Conservation 43: 195-99. (from Wenger 1999) Lowrance, R., G. Vellidis, R. D. Wauchope, P. Gay and D. D. Bosch. 1997. Herbicide transport in a managed riparian forest buffer system. Transactions of the ASAE 40 (4): 1047-1057. (from Wenger 1999) Lowrance, R.R., R.L. Todd, and L.E. Asmussen. 1984. Nutrient cycling in an agricultural watershed — I: phreatic movement. Journal of Environmental Quality 13:22-27. (from Mayer et al 2005) Lynch, J. A., E. S. Corbett, and K. Mussallem. 1985. Best management practices for controlling nonpoint source pollution on forested watersheds. J. Soil Water Conserv. 40:164-167. (from Knutson and Naef 1997; Castelle et al 1994; Fischer et al 2000; Mayer et al 2005) Madison, C.E., R.L. Blevins, WWFrye, and B.J. Bar- field. 1992. Tillage and grass filter strip effects upon sediment and chemical losses. P. 331. in Agronomy abstracts. ASA, Madison, WI (from Castelle et al 1994) Magette, W.L., Brinsfield, R.B., Palmer, R.E., Wood, J.D., Dillaha, T.A. and Reneau, R.B. 1987 Vegetated fil- ter strips for agriculture runoff treatment. United States Environmental Protection Agency Region III, Report #CBP/TRS 2/87-003314-01. (from Wenger 1999) Magette, W L., R. B. Brinsfield, R. E. Palmer and J. D. Wood. 1989. Nutrient and sediment removal by vegetated filter strips. Transactions of the ASAE 32(2):663-667. (from Wenger 1999; Mayer et al 2005) Mander, U, V. Kuusemets, K. Lohmus, T. Mauring. 1997. Efficiency and dimensioning of riparian buffer zones in agricultural catchments. Ecological Engi- neering 8:299-324. (from Wenger 1999) Martin, T.L., N.K. Kaushik, H.R. Whiteley S. Cook, and J.W Nduhiu. 1999. Groundwater nitrate con- centrations in the riparian zones of two southern Ontario streams. Canadian Water Resources Jour- nal 24:125-138. (from Mayer et al 2005) Mayer, P.M., Steven K. Reynolds, Jr., Timothy J. Canfield. 2005. Riparian buffer width, vegetative cover, and nitrogen removal effectiveness: a review of current science and regulations. U.S. Environmental Pro- tection Agency, EPA/600/R-05/118, National Risk Management Research Laboratory, Ada, OK, 28 pp. Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality Montana Department of Environmental Quality (DEQ). 2007. Montana Nonpoint Source Management Plan. Helena, Montana. Water Quality Planning Bureau. 138 pp. Moring, J.R. 1982. Decrease in stream gravel permeability after clear-cut logging: an indication of intragravel conditions for developing salmonid eggs and alevins. Hydrobiologia 88:295-298. (from Knutson and Naef 1997) Muscutt, A. D., G. L. Harris, S.W . Bailey and D. B. Davies. 1993. Buffer zones to improve water quality: A review of their potential use in UK agricul- ture. Agriculture, Ecosystems and Environment 45:59-77. (from Wenger 1999) Nichols, D. J., T. C. Daniel, D. R. Edwards, P A. Moore, and D. H. Pote. 1998. Use of grass filter strips to reduce 17 Beta-estradiol in runoff from fescue- applied poultry litter. Journal of Soil and Water Conservation 53:74-77. (from Fischer et al 2000) Osborne, L. L. and D. A. Kovacic. 1993. Riparian veg- etated buffer strips in water-quality restoration and stream management. Freshwater Biology 29:243-258. (from Wenger 1999; Mayer et al 2005) Peterjohn, W T. and D. L. Correll. 1984. Nutrient dynam- ics in an agricultural watershed: Observations on the role of a riparian forest. Ecology 65(5):i466-i475. (from Wenger 1999; Mayer et al 2005)) Petersen, R. C, L. B. M. Petersen, and J. Lacoursiere. 1992. A building-block model for stream restoration. In P. J. Boon, P. Calow, and G. E. Petts, eds. River con- servation and management. Wiley and Sons, New York, N.Y. 470 pp. (from Knutson and Naef 1997) Pinay, G., and H. Decamps. 1988. The role of riparian woods in regulating nitrogen fluxes between allu- vial aquifer and surface water: a conceptual model. Regulated Rivers: Research and Management 2:507-516. (from Mayer et al 2005) Pinay, G., L. Roques, and A. Fabre. 1993. Spatial and temporal patterns of denitrification in riparian for- est. Journal of Applied Ecology 30:581-591. (from Mayer et al 2005) Prach, K., and O. Rauch 1992. On filter effects of eco- tones. Ekologia (CSFR) 11:293-298. (from Mayer et al 2005) Puckett, L.J., T.K. Cowdery PB. McMahon, L.H. Tornes, and J.D. Stoner. 2002. Using chemical, hydrologic, and age dating analysis to delineate redox processes and flow paths in the riparian zone of a glacial outwash aquifer-stream system. Water Resources Research 38:10.1029. (from Mayer et al 2005) Schellinger, D.R. and J.C. Clausen. 1992. Vegetative fil- ter requirements of dairy barnyard runoff in cold regions. J. Environ. Qual. 21:40-45. (from CasteUe et al 1994) Schmitt, T.J., M.G. Dosskey, and K.D. Hoagland. 1999. Filter strip performance and processes for different vegetation, widths, and contaminants. Journal of Environmental Quality 28:1479-1489. (from Mayer et al 2005) Schoonover, J.E., and K.W.J. WilHard. 2003. Groundwater nitrate reduction in giant cane and forest ripar- ian buffer zones. Journal of the American Water Resources Association 39:347-354. (from Mayer et al 2005) Schultz, R. C, J. P CoUetti, T. M. Isenhart, W W Simp- kins, C. W Mize, and M. L. Thompson. 1995. Design and placement of a multi-species riparian buffer strip system. Agrofor. Sys. 29:201-226. (from Knutson and Naef 1997; Mayer et al 2005) Schwer, C.B., and J.C. Clausen. 1989. Vegetative filter strips of dairy milkhouse wastewater. Journal of Environmental Quality 18:446-451. (from Mayer et al 2005) Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality Shisler, J. K.., R. A. Jordan, and R. N. Wargo, 1987. Coastal Wetland Buffer Delineation. New Jersey Depart- ment of Environmental Protection, (from Castelle et al 1994; Fischer et al 2000) Simmons, R.C., A.J. Gold, and P.M. Groffman. 1992. Nitrate dynamics in riparian forests: groundwa- ter studies. Journal of Environmental Quality 21:659-665. (from Mayer et al 2005) Spruill, T.B. 2004. Effectiveness of riparian buffers in controlling ground-water discharge of nitrate to streams in selected hydrogeological settings of the North Carolina Coastal Plain. Water Science and Technology 49:63-70. (from Mayer et al 2005) Terrell, C. R., and P. B. Perfetti. 1989. Water quality indi- cators guide: surface waters. U.S. Soil Conserv. Serv. SCS-TP-161. Washington, D.C. 129 pp. (from Knutson and Naef 1997) Vanderholm, D.H. and E.G. Dickey 1978. ASAE Pap. 78-2570. ASAE Winter Meeting, Chicago, IL. ASAE, St. Joseph, MI. (from Castelle et al 1994) Vellidis, G., R. Lowrance, P. Gay, and R.K. Hubbard. 2003. Nutrient transport in a restored riparian wetland. Journal of Enviromental Quality 32:711-726. (from Mayer et al 2005) Vidon, P.G.F., and A.R. Hill. 2004. Landscape controls on nitrate removal in stream riparian zones. Water Resources Research 4o:Wo320i. (from Mayer et al 2005) Vought, L. B.-M., J. Dahl, C. L. Pedersen and J. O. Lacoursi're. 1994. Nutrient retention in riparian ecotones. Ambio 23(6):343-348. (from Wenger, 199) Wenger, S.J. 1999. A review of the scientific literature on riparian buffer width, extent and vegetation. Ath- ens: Institute of Ecology Office for Public Service and Outreach, University of Georgia. 59 pp. Woodard, S. E., and C. A. Rock, 1995. Control of residen- tial stormwater by natural buffer strips. Lake and Reservoir Management, 11:37-45. (from Fischer et al 2000) Xu, L. J.W GiUiam, and R.B. Daniels. 1992. Nitrate move- ment and loss in riparian buffer areas. P. 342. In Agronomy abstracts. ASA, Madison, WI. (from Castelle et al 1994) Young, R. A., T. Huntrods, and W Anderson. 1980. Effec- tiveness of vegetated buffer strips in controlling pollution from feedlot run-off. J. Environ. QuaL 9:483-497. (from Knutson and Naef 1997; Castelle et al 1994; Wenger 1999; Fischer et al 2000; Mayer et al 2005) Zirschky, J., D. Crawford, L. Norton, S. Richards, D. Deemer. 1989. Ammonia removal using overland flow. Journal of the Water Pollution Control Fed- eration 61:1225-1232. (from Mayer et al 2005) 23 Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality Acknowledgements A special thanks goes to the following individu- als who provided advice, editorial counsel, and support for this publication: Chris Clancy and Doris Fischer (FWP), Lynda Saul and Taylor Greenup (DEQ), and Dr. Vicky Watson (Univ. of Montana). Geoff Wyatt, of Wyatt Design, designed the report and developed the illustra- tion on page 3. Rick Newby, Zadig, LLC, copyedited the text. Financial Support for this report came from the Montana Dept. of Environmental Quality (DEQ); U.S. Environmental Protection Agency; Montana Fish, Wild- life & Parks (FWP); the Liz Claiborne/ Art Ortenberg Foundation; and Montana Audubon. 24 Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Fish and Aquatic Habitat PART Two of a Series entitled: The Need for Stream Vegetated Buffers: What Does the Science Say? Janet H. Ellis Montana Audubon Helena, Montana (406) 443-3949 www.mtaudubon.org Prepared for: Montana Department of Environmental Quality EPA/DEQ Wetland Development Grant 998117-14 Helena, Montana June 2008 This document should be cited as: Ellis, J.H. 2008. Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Fish and Aquatic Habitat, Part Two, The Need for Stream Vegetated Buffers: What Does the Science Say? Report to Montana Department of Environmental Quality, EPA/DEQ Wetland Development Grant. Montana Audubon, Helena, MT. 20 pp. This report is available at mtaudubon.org Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Fish and Aquatic Habitat Introduction All freshwater fish depend primarily on two things: i) an adequate, clean water supply, and 2) a healthy system of riparian vegetation along our streams, lakes, and wetlands. These two items work in tandem to provide the necessary areas for breed- ing, feeding, resting, and avoiding predators during the different phases of a fish's lifecycle. One of the most effective tools available to local governments interested in minimizing the loss and degradation of fish habitat along streams is to set back struc- tures and protect streamside buffers with native vegetation (hereafter referred to as "building set- backs with vegetated buffers"). In order to use this tool, however, decision makers and citizens alike must understand the science behind differ- ent buffer widths. This second report, in a series, summarizes the scientific recommendations underlying the veg- etated buffer size needed to protect fish and aquatic habitat. Two other reports were developed in this series on other key elements of stream protection, water quality and wildlife: • Part I: Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Water Quality; and • Part III: Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Wildlife and Wildlife Habitat. Each of these reports is designed to explain the science behind one of the many functions provided by vegetated buffers found along streams. Other topics for this series are currently being considered because decision makers establishing building set- backs with vegetated buffers should also consider floodplains and seasonal water levels, stream migra- tion corridors, density of development adjacent to the riparian corridor, and other factors. For more information on how building set- backs relate to vegetated buffers, see page 3. Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Fisli and Aquatic Habitat Building Setbacks and Vegetated Buffers In order to understand setbacks and buf- fers, it is important to understand the following concepts: Building setbacks or "no build areas" are the distance from a stream's ordinary high water mark to the area where new structures and other developments (such as highly polluting land uses — including roads, parking lots, and waste sites) are allowed. Vegetated Buffers are not an additional area, but rather the portion of the building set- back that is designated to remain undisturbed. These buffers are areas where all native vegeta- tion, rocks, soil, and topography are maintained in their natural state, or enhanced by additional planting of native plants. Lawns should not be considered part of the vegetated buffer. With their shallow roots, lawns are not particularly effective at absorbing and retaining water, espe- cially during heavy rains. Consequently, they do not significantly filter out water pollutants. They can also be a major source of fertilizers and pesticides — substances that should be prevented from entering our streams and rivers. Howmuch space should be placed between a building and a vegetated buffer? The building setback should be wide enough to prevent deg- radation of the vegetated buffer. As an example, most families use the area between their home and the vegetated buffer for lawns, play areas, swing sets, picnic tables, vegetable gardens, landscaping, etc. As a result, the building setback should extend at least 25-50 feet beyond the veg- etated buffer (Wenger 1999). A smaller distance between a building and a vegetated buffer, such as 10 feet, will most likely guarantee degrada- tion of the vegetated buffer. A greater distance between structures and a vegetated buffer is rec- ommended if the: • River has a history of meandering; the set- backs should ensure that people and homes will not unwittingly be placed too close to the river's edge, in harm's way. • Vegetated buffer is narrower than scien- tific studies recommend; a deeper building setback can help protect water quality, fish- eries, and aquatic habitat. • Land is sloped and runoff is directed toward the stream (the steeper the slope, the wider a buffer or setback should be). • Land use is intensive (subdivisions, crops, construction, development). • Soils are erodible. • Land drains a large area. • Aesthetic or economic values need to be preserved. • Wildlife habitat needs to be protected. • Landowners desire more privacy. Vegetated Buffer Building Setback Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Fisli and Aquatic Habitat A Definition of Riparian Areas This term means "related to, living on, or located on" the bank of a stream or lake. Riparian areas occur along the shorelines of streams, rivers, lakes, and reservoirs. Some are narrow bands stretching along moun- tain streams, others stretch thousands of feet beyond the water's edge across broad flood- plains. Plants associated with riparian areas include cottonwoods, willows, dogwood, alder, sedges, forbs, cattails, and more. Vegetated Buffers, Fish & Aquatic Habitat There is a growing concern in Montana over the status of our native fish communities. Keeping an adequate vegetated buffer along a stream is the most important thing that individual landowners can do to improve or maintain fish habitat — both for the stream passing thorough a landowner's property, as well as for the river downstream. In Montana, we have 85 species of fish that depend on healthy streams, including 51 species of native fish and 32 non-native (introduced) fish. Two additional species are possibly native. Twenty-six of these species are considered game fish, important to fishing and the economy (fiolton and Johnson, 2003). In order to understand the habitat requirements of fish, two basic principles should be understood. First, a stream with a healthy invertebrate population (e.g. aquatic insects, crustaceans, snails, and worms) usually indicates that the fish habitat is also healthy. Aquatic invertebrates are the major food source for many, if not most, freshwater fish. Even predacious fish feed heavily on invertebrates when they are juveniles. As a result, scientific studies on fish frequently focus on the health of a stream's invertebrate populations. A second principle worth emphasizing is that natural stream processes are critical for most fish species because fish have evolved with natural pro- cesses — and the habitat requirements of fish are diverse. As an example, some fish prefer small streams (e.g. creek chub, brassy minnow, several species of sculpin, many spawning fish), others are primarily found in large rivers or lakes (e.g. burbot, gar, pad- dlefish, sturgeon, walleye); some require clear, cold water (e.g. trout, grayling, whitefish, mountain suck- ers), while others need turbid, warmer water (e.g. channel catfish, some chub, goldeye, sauger, sun- fish); some species prefer pools and backwater areas (e.g. river carpsucker, largemouth bass), while oth- ers prefer strong currents (e.g. pallid and shovelnose sturgeon, stonecat); some like dense aquatic vegeta- tion (e.g. carp, peamouth, pike, shiners, stickleback), while others need clear water and overhanging veg- etation (many trout); and some fish prefer a gravel stream bottom (e.g. rock and smallmouth bass, many spawning fish), while others prefer a sandy or muddy bottom (e.g. largemouth bass, sand shiner, black bullhead) (Holton and Johnson, 2003). Additionally, fish can use different parts of the aquatic environ- ment during different parts of their lifecycle. As an example, bull trout use larger streams or lakes during much of the year, but use small, clean gravel-bot- tomed streams to spawn. Because different fish have different habitat requirements, maintaining natural Artwork of the burbot by Joe Tomelleri, courtesy Montana Fish, Wildlife & Parks. Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Fisli and Aquatic Habitat stream processes is the simplest way to protect Mon- tana's diverse fish populations. Specific ways that streamside buildings and their associated development (roads, parking lots, construction sites, etc.) can impact fish and aquatic habitat are described below: Riparian Vegetation and Woody Debris Fish and aquatic insects need clean water. Riparian vegetation plays a critical role at keeping sediments and other pollutants out of our streams and rivers (see Sedimentation below). It also is the main source of leaves, twigs, and other organic material that provides a large proportion of the food and breeding grounds for invertebrates that, in turn, feed fish and other wildlife. Large woody debris (LWD), which is gener- ally defined as pieces of wood at least 20 inches (51 cm) in diameter, is important to both Mon- tana's cold and warm water fisheries. When trees, root systems, branches, and other LWD fall into streams, they create critical fish habitat by devel- oping: scour holes, rifles, and areas for spawning gravels to accumulate; pool habitats that provide critical refuges when summer temperatures get high; and small dams that keep natural organic litter and food from washing downstream, which helps fish as well as the invertebrates they eat. Trees also provide underwater resting areas and cover from predators in roots, submerged logs, and other debris. Scientists consider LWD to be one of the most important factors in determining critical habitat for trout and salmon (salmonids) (Knutson and Naef 1997). Construction of homes and their associ- ated developments along streams and rivers often results in removal of riparian vegetation and woody debris because of the human tendency to "manage their property" and "tidy up the yard." Removing trees — including dead tree snags — in riparian areas or cleaning trees from the stream can cause stream channels to become simpler and less stable. Simpler stream channels mean fewer, shallower, and less-complex pool habitats; more distance between low-velocity refuges for fish dur- ing high flows; and fewer places for fish to hide or escape from predators. Additionally, less large woody debris in a stream reduces the retention and sorting of spawning gravels, as well as the amount of leaf litter and other organic material available for invertebrates. Local governments interested in determin- ing the fish species using streams within their jurisdiction should contact their local office of Montana Fish, Wildlife & Parks and the Montana Natural Heritage Program located in Helena (406-444-5354 or http://nhp.nris. mt.gov/). Stream Temperatures Fish are 'cold-blooded' animals. Conse- quently, their body temperature is about the same as the water temperature in which they live (i.e. if the water is hot, the fish are hot) — and the water temperature directly influences their rate of development, metabolism, and growth. Water tem- peratures also influence the amount of dissolved oxygen in water, with less oxygen found in warmer temperatures. Both of these factors influence the range and distribution offish species in Montana. As an example, we have cold water fish, primarily located in the western part of the state, and warm water fish, primarily located in eastern Montana. Cold water fish include trout, salmon, and white- fish; they are adapted to living in water temperatures Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Fisli and Aquatic Habitat lower than 65° F (24°C). Because fish are so sensitive to temperature — even minor shifts in temperature can cause changes in the fish community — having shade over the surface of streams is a critical part of fish habitat. By shad- ing sections of a stream channel, trees and shrubs, such as cottonwoods, birch, alder, pine, and wil- low, help control and moderate water temperature, keeping streams cooler in the summer and warmer in the winter. Streamside vegetation also protects streams from wind and increases the local humid- ity, both important factors for some adult stages of aquatic insects. Removal of vegetation that provides shade can result in summer temperatures that can be stressful or lethal to invertebrates and fish — for both cold and warm water fisheries. The Role of Small Streams Small, tributary streams need and deserve at least as much protection as larger rivers because they: contribute steady amounts of clean, cooler water to mainstem rivers; filter sediments and pollutants; play a key role in the retention and absorption of flood and storm water in a watershed; are an important water source, especially during low flow periods of the year; are a major source of woody debris and other organic matter necessary for aquatic organisms; and provide critical spawning sites for many fish species. In terms of temperature, even small streams that do not hold fish can benefit from shade, which keeps water cooler for habitat downstream. Additionally, small streams that are shaded provide the greatest temperature reduction per unit length — directly benefiting Mon- tana's mainstem rivers. These streams are so critical for Montana's fisheries that an increase in the tem- perature and/or sedimentation of tributary streams can directly decrease the useable habitat for fish, as well as reduce their reproductive success. -^ Artworl< of the Yellowstone cutthroat by Joe Tomelleri, courtesy Montana Fish, Wildlife & Parks. Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Fisli and Aquatic Habitat This home was built out of the floodplain — but on an erosive banl< overlooking the Shields River. In areas where streams are known to meander, building setbacks and vegetated buffers should incorporate non-floodplain areas overlooking the stream — because as valley stream channels naturally meander, these homes can become vulnerable to falling into the water Because of their size, small tributaries are very vulnerable to impacts from housing and other development: they are shallower, so removing trees and other shade-producing vegetation can result in harmful increases in temperature and increased evaporation rates; and they have less water, so it is easier for debilitating or toxic concentrations of pol- lutants to impact aquatic organisms in these streams. Additionally, many small tributaries are often dependent upon groundwater to maintain late sum- mer stream flows. If a housing development reduces or eliminates their access to this groundwater, these streams can partially or entirely dry up — a condition that is obviously stressful or lethal to fish and other stream organisms. Bank Stabilization As described above, the long-term health of streams, fish, and aquatic habitat requires main- taining natural stream processes — which includes natural erosion processes. In a healthy valley stream or river, banks erode naturally and the material is deposited elsewhere, which in turn builds banks and their associated floodplain. As a result of this natural process, the location of the stream channel changes over time. If given space, meandering streams cre- ate a pattern where outside bends of the stream are dominated by cut banks (caused by natural erosion), and inside bends are dominated by sand or gravel bars (where sediment is deposited). If homes or other developments are built too close to a meandering stream or on a bluff overlook- ing a river, landowners will eventually request that bank stabilization structures — riprap, weirs, barbs, and other structures — be built to protect their home from eventually falling into the water. As more bank stabilization structures are built, both short-term and long-term consequences arise. In the short-term, stabilization measures tend to physically secure one local stretch of riverbank or divert flows away from one bank to another. This can trigger increases in river flow velocities, exacerbate downstream bank erosion, and lead to ftirther instabilities down- stream. In other words, preventing natural erosion at one location can significantly increase erosion downstream of the project. Therefore the "problem" is neither controlled nor solved, but merely relo- cated from one spot to another, negatively impacting downstream landowners. Increased downstream erosion often causes affected landowners to put in structures to protect their property — and the cycle repeats itself over and over again. Scientific studies show that structurally diverse streams, unmodi- fied by human activity, are critical to sustaining fish populations (e.g. Schmetterling et al 2001). In the long-term, bank stabilization structures negatively impact fish habitat by simplifying the structure of the stream, resulting in a loss of species and fish numbers. The simplest way to eliminate this problem is to not allow homes and other associated develop- ment to be built in the floodplain — and to establish setbacks in areas located above the floodplain where streams wiU likely meander. Scientific Recommendations on the Size of Stream Vegetated Buffers Needed to Protect Fisli and Aquatic Habitat Sedimentation In addition to being sensitive to water pollut- ants, fish can be extremely intolerant of sediment in the stream. Sediments come from a variety of sources, including natural and human-driven stream bank erosion, agricultural fields, exposed earth at construc- tion sites and on dirt roads, and other activities that remove vegetation and expose soil. Scientific studies show that, during heavy rainstorms, land covered with native riparian vegetation can absorb 95% of the pre- cipitation, depositing only 5% of the relatively silt-free water into nearby streams (Knutson and Naef 1997). Although many Montana fish are somewhat tolerant of sediment, many of our trout species — including our native buU trout and cutthroat trout — tend to be very sensitive to sUtation. As an example, trout require and seek out clean (silt-free) gravel to lay their eggs. Fine sediment suspended in water wiU suffocate eggs and interfere with the feeding of juvenile trout, reducing their growth rates. And trout are not the only fish affected by too much sedimentation: several of Mon- tana's warm water fish need clean gravels to spawn, including the long-nosed dace, stonecat, and goldeye. Too much suspended sediment can also cause irrita- tion of gOl tissues and force fish to avoid a stream or section of stream altogether The bottom line is that sediment deposited on stream beds reduces habitat for fish and for the invertebrates that many fish con- sume — and high levels of sediment can kill aquatic insects and fish. Removing riparian vegetation, including manicuring the landscape, reduces the ability of natural vegetation to filter out sediments and other pollutants. As stated earlier, keeping an ade- quate vegetated buffer along a stream is the single most important thing individual landowners can do to improve or maintain fish habitat. For more infor- mation on the role that vegetated buffers play in protecting water quality, see the water quality report in this series (Ellis 2008). About This Report — Methods Used This report summarizes the recommendations of more than 34 scientific studies that tested how various stream vegetated buffers protected fish and aquatic habitat (see Appendix I). These scientific studies were reviewed by the authors of 3 review publications. One additional source was included because it contains on-the-ground management recommendations for fisheries in Montana. Please note that the informa- tion in this report was taken from the text and tables of these 4 publications — and that the original studies were not reviewed. The 3 review publications are: Castelle, A.J., A. W. Johnson, and C. Conolly 1994. Wetland and stream buffer size requirements — a review. J. Environ. Qual. 23: 878-882. Knutson, K. L. and V. L. Naef 1997. Management recommendations for Washington's priority habitats: riparian. Wash. Dept. Fish and Wild- life, Olympia, WA. 181 pp. Wenger, S. J. 1999. A review of the scientific lit- erature on riparian buffer width, extent and Artworl30 >100 Spackman and Hughes 1995 Fischer et al 2000 General wildlife habitat — depends on species 9-201 30-660 Johnson and Ryba 1992 Knutson and Naef i997;Castelleet al 1994 Width of riparian vegetation — depends on species 20-50 66-164 Strong and Bock 1990 Knutson and Naef 1997 REPTILES AND AMPHIBIANS 1 1 i Meters Feet ^^hor of Orig^^^ Scientific Study Name of Review Article Reptiles and amphibian habitat >165 >540 Semlitsch 1998 Fischer etal 2000 Reptile and amphibian habitat >135 >443 Buhlmann 1998 Fischer etal 2000 Reptiles and amphibian habitat 100 328 Burbrinket al 1998 Wenger 1999; Fischer et al 2000 Reptiles and amphibian habitat — buffer requirements for riparian- dependent species 75-100 246-328 Gomez and Anthony 1996 Wenger 1999 Reptiles and amphibian habitat — riparian-dependent species more numerous with buffer width in mature vegetation 30-95 100-312 Rudolph and Dickson 1990 Knutson and Naef 1997 Reptiles and amphibian habitat — Full complement of reptiles and amphibians >30 >ioo Rudolph and Dickson 1990 Knutson and Naef 1997; Fischer et al 2000 Reptile habitat — requirements for certain fresh water turtles 275 902 Burke and Gibbons 1995 Wenger 1999 Scientific Recommendations on the Sizeof Stream Vegetated Buffers Needed to Protect Wildlife and Wildlife Habitat REPTILES AND AMPHIBIANS (conti^g ~1 ■l~in--r^-";F-^?-^3' a l^f^^ ^^— Amphibian habitat — Distance needed Ermanetali977, for sediment control, Important to Lynch et al 1985, maintaining habitat quality for Cascade Terrell and Perfetti torrent, Columbia torrent, Dunn's, and 1989, Johnson and Knutson and Naef 1997; Fischer Van Dyke's salamanders 31-88 100-289 Ryba 1992 et al 2000 Bottom etal 1983, Amphibian habitat — Distance needed Harmon etal 1986, for woody debris recruitment, an impor- Murphy and Koski tant habitat component for Cascade 1989, McDade etal torrent, Columbia torrent, Dunn's, and 1990, Van Sickle and Van Dyke's salamanders 31-55 100-180 Gregory 1990 Knutson and Naef 1997 ^^^^^ ^^^^^^^^^H ^"^ ' -■ ■ Author of Original ■ n 1 General Bird Habitat ' 1 . ^ -':.■ -« ^^..., --. ^ .-?• ?i,i* - J Bird habitat — size of naturally veg- etated buffer needed to retain full complement of birds 125 410 Croonquist and Brooks 1993 Knutson and Naef 1997 Bird habitat — Full compliment of birds present; avian richness declines after this point in cottonwood floodplains 127 417 Sedgewickand Knopf 1986 Knutson and Naef 1997 Bird habitat — riparian buffer size needed to include 90% of bird species along mid-order streams 150-175 492-574 Spackman and Hughes 1995 Wenger 1999; Fischer 2000; Fischer et al 2000 Bird habitat — Riparian buffers should be at least this wide to provide some nesting habitat for sensitive species 100 328 Keller etal 1993 Fischer 2000 Bird habitat — recommended buffer for birds 75-200 246-656 Jones etal 1988 Knutson and Naef 1997 Bird habitat — minimum buffer width recommended for bird species 70 230 Kinleyand Newhouse 1997 Wenger 1999 Bird habitat — bottomland hardwood strips can support diverse bird popula- tions; at least 500 m needed to maintain complete avian community 50-500 164-1640 Kilgo etal 1998 Wenger 1999; Fischer 2000; Fischer etal 2000 Bird habitat — buffer distance needed to provide sufficient breeding habitat for area-sensitive forest birds. >100 >328 Mitchell 1996 Fischer 2000; Fischer et al 2000 Bird habitat — 45% reduction in birds in agricultural areas if no fencerows are within this distance of a stream 100 328 Croonquist and Brooks 1993 Knutson and Naef 1997 Bird habitat — bird species sensitive to disturbance did not occur unless an undisturbed corridorthis wide was present 25 82 Croonquist and Brooks 1993 Knutson and Naef 1997 Scientific Recommendations on the Sizeof Stream Vegetated Buffers Needed to Protect Wildlife and Wildlife Habitat ^Hhor of Orig^^^^l ^c^ntific Study "NUme of Review Article Bird habitat — depends on species 50-1,600 164-5,250 Richardson and Miller 1997 Fischer etal 2000 Bird forest Kiabitat — minimum riparian width to sustain forest-dwelling birds >6o >200 Darveauetal 1995 Knutson and Naef 1997; Fischer 2000; Fischer et a 1 2000 Bird forest Kiabitat — riparian buffers along headwater streams provide the most benefit for forest-associated bird species if they are >40 m >40 >131 Hagar 1999 Fischer 2000; Fischer et al 2000 Bird habitat — Narrow stream corridors (15-50 m) can help maintain bird diver- sity even though they are insufficient for protecting forest-dependent species 15-50 50-164 Thurmond etal 1995 Wengeri999 Bird forest habitat — small buffers will benefit some edge-dwelling songbirds 15-23 49-76 Triquetetali990 Wengeri999 Birds-Nest Predation J Nest predation — Brown-headed Cowbird — distance cowbirds penetrate from stream opening 240 787 Gates and Giffin 1991 Knutson and Naef 1997 Nest predation — riparian buffers this wide reduce edge-related nest preda- tion. >150 >490 Vander Haegenand deGraaf 1996 Fischer etal 2000 Nest predation — riparian buffer width that reduces nest predation 100 328 Temple 1986 Knutson and Naef 1997 Watoi-fnwl ^^^^^^^^ Wood Ducic — maximum distance from water where Wood Ducks will nest 350 1148 Gilmer etal 1978 Knutson and Naef 1997 Wood Ducit — nest within this distance 200 656 Lowneyand Hill 1989 Knutson and Naef 1997 Wood Ducl( — nesting distance 183 600 Grice and Rogers 1965 Knutson and Naef 1997 Wood Ducl( — nesting where woody/ herbaceous cover is between 50-75% 183 600 Sousa and Farmer 1983 Knutson and Naef 1997 Wood Ducli — average distance of wood duck nests from water 80 262 Gilmer etal 1978 Knutson and Naef 1997 Lesser Scaup prefer nesting habitat within this distance in emergent vegeta- tion 50 164 Allen 1986a Knutson and Naef 1997 Harlequin — stream buffer needed to maintain harlequin nests 50 164 Cassirer and Groves 1990 Knutson and Naef 1997 Harlequin — large woody debris use by loafing Harlequin Ducks 30-H lOO-H Murphy and Koski 1989 Knutson and Naef 1997 Cavity nesting ducks (includes Wood Ducks, goldeneye, Buffelhead, and Hooded Merganser) 182 600 Cohen 1997 Ellis and Richard 2008 Scientific Recommendations on the Sizeof Stream Vegetated Buffers Needed to Protect Wildlife and Wildlife Habitat I hor of Original ^" ~^^^^^^^H Mfetfefs F6et^^ _--i-« i fie of Review Article am iimi[j^<>lji^H Birds — Species information (Birds generally listed in taxonomic order) _^^^^ \ n Waterfowl ^^^^^| J Dabbling ducks (includes Pintail, teal, widgeon. Mallards, shoveler, etc.) 100 330 Cohen 1997 Ellis and Richard 2008 Grouse and their Allies . ti:,-" Ring-necked Pheasant — buffer size needed in Eastern Washington 23 75 Mudd 1975 Knutson and Naef 1997 Spruce Grouse— minimum buffer width to sustain 60 197 Darveauetali995 Knutson and Naef 1997 Herons and Cranes ^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^n Great Blue Heron — minimum buffer zone around peripheries of Great Blue Heron colonies 250-300 820-984 Bowman and Siderius 1984, Kelsall i989,Voset all985 Knutson and Naef 1997 Great Blue Heron — nesting 250-300 820-984 Parker 1980, Short and Cooper 1985, Vosetal 1985 Knutson and Naef 1997 Great Blue Heron — recommended disturbance-free zone around heron nesting areas 250 820 Short and Cooper 1985 Knutson and Naef 1997 Great Blue Heron — nesting 250 820 Short and Cooper 1985 Knutson and Naef 1997 Great Blue Heron — recommended disturbance-free zone around heron feeding areas 100 328 Short and Cooper 1985 Knutson and Naef 1997 Sandhill Cranes — recommended disturbance-free zone around Sandhill Crane nesting areas 400 1,312 Schlorffetali983 Knutson and Naef 1997 Raptors Osprey nesting — recommended hiking trail buffer near Osprey nests 91 300 Zarn 1994 Knutson and Naef 1997 Osprey nesting — no cut zone 61 200 Zarn i974,Westall 1986 Knutson and Naef 1997 Bald Eagle — distance from human activity at which nesting eagles are disturbed 400 1,320 Montana Bald Eagle Working Group 1991 Ellis and Richard 2008 Bald Eagle — recommended buffer for eagle perch areas with little screening 250-300 820-984 Stalmaster 1980 Knutson and Naef 1997 Bald Eagle — distance from human activity at which feeding eagles are disturbed 200 656 Skagen 1980 Knutson and Naef 1997 Bald Eagle — average distance of suc- cessful Bald Eagle nests from human disturbance 119 396 Grubb 1980 Knutson and Naef 1997 Bald Eagle — eagles nest within this distance of water 100 328 Small 1982 Knutson and Naef 1997 13 Scientific Recommendations on the Sizeof Stream Vegetated Buffers Needed to Protect Wildlife and Wildlife Habitat I ^^ Author of Original ^^" 1 rof Review Article 1 J Meiers heei bcientinc biuay^j Raptors (continued) J ^ 1 1 •« Bald Eagle — recommended leave strip for Bald Eagles along shoreline of major feeding areas 75-100 246-328 Stalmaster 1980 Knutson and Naef 1997 Bald Eagle — most Bald Eagles perch within this distance of water during daylight hours 50 164 Stalmasteri98o Knutson and Naef 1997 Doves, Cuckoos, and Kingfishers ^^^^ Mourning Dove 15 50 Muddi975 Knutson and Naef 1997 Belted Kingfisher roosts 30-60 100-197 Prose 1985 Knutson and Naef 1997 Yellow-billed Cuckoo — loo meter mini- mum riparian buffer width for breeding habitat; stream length must be at least 300 meters >100 >328 Gaines 1974 Knutson and Naef 1997; Fischer 2000 Yellow-billed Cuckoo — buffer required by cuckoo 91 300 Gaines and Laymon 1984 Knutson and Naef 1997 Woodpeckers ^^^»_^^^^ 1 Downy Woodpecker 25 82 Staufferand Best 1980 Knutson and Naef 1997 Downy Woodpecker 15 50 Cross 1985 Knutson and Naef 1997 Hairy Woodpecker — minimum mean width supporting breeding populations of H a i ry Wood pec ke rs 40 133 Staufferand Best 1980 Knutson and Naef 1997 Northern Flicker avoided isolated for- est patches farther than this distance from water 124 407 Gutzwiler and Anderson 1987 Knutson and Naef 1997 Pileated Woodpecker — nesting 150-183 492-600 Conner etal 1975, Schroederi983 Knutson and Naef 1997 Pileated Woodpecker — most Pileated Woodpeckers nest within this distance of water 150 492 Conner et al 1975, Schroeder 1983 Knutson and Naef 1997 Pileated Woodpecker — nesting within this distance of stream 100 328 Small 1982 Knutson and Naef 1997 Pileated Woodpecker do not use buf- fers this size 15-23 50-75 Triquetetah990 Knutson and Naef 1997 Songbirds (Songbirds that are "Neotropical Migrants" breed in Montana but winter in the neotropics (Central and Neotropical Migrants were more abun- dant in riparian corridors wider than loo meters >100 >328 Triquet et al 1990 Knutson and Naef 1997; Fischer 2000; Fischer et al 2000 Neotropical Migrants — distance needed to maintain functional assem- blages of 6 common neotropical migratory birds >100 >328 Hodges and Krementzi996 Knutson and Naef 1997; Wenger 1999; Fischer 2000; Fischer et al 2000 14 Scientific Recommendations on the Sizeof Stream Vegetated Buffers Needed to Protect Wildlife and Wildlife Habitat 1 Author of Original ^^" 1 rof Review Article J Meiers heei bcientinc biuay^j Songbirds (continued) ^^ ! ^ 1 m Neotropical Migrants — minimum buffer width needed to support area- sensitive neotropical migrant birds In forest/agricultural areas 100 328 Keller etal 1993 Knutson and Naef 1997; Wenger 1999; Fischer et al 2000 Neotropical Migrants — sensitive spe- cies of flycatchers and warblers inhabit buffers of this size 75-150 246-492 Smith and Schaefer 1992 Wenger 1999 Neotropical Migrants — minimum riparian width to sustain neotropical migrants (many neotropical birds will not inhabit narrower buffers) >50 164 Tassone 1981 Knutson and Naef 1997; Fischer 2000 Neotropical Migrants — significant increases in bird densities found for several species 50-100 164-328 Hodges and Krementzi996 Wenger 1999 Neotropical Migrants — narrow buffer supports more songbirds than no buffer near agricultural fields 50 164 Keller etal 1993 Wenger 1999 Neotropical Migrants — sensitive spe- cies of flycatchers and warblers missing from buffers of this size 20-60 66-197 Smith and Schaefer 1992 Wenger 1999 Neotropical Migrants do not use buf- fers this size 15-23 50-75 Triquet et al 1990 Knutson and Naef 1997 Warbling Vireo — average distance of warbling vireo nests from water 90 295 Gilmer etal 1978 Knutson and Naef 1997 Red-eyed Vireo — minimum mean width supporting breeding populations of red-eyed vireos 40 133 Staufferand Best 1980 Knutson and Naef 1997 Black-capped Chickadee 15 50 Cross 1985 Knutson and Naef 1997 White-breasted Nuthatch 17 57 Staufferand Best 1980 Knutson and Naef 1997 Brown Creeper — minimum buffer width to sustain 60 197 Darveau etal 1995 Knutson and Naef 1997 Ruby-crowned Kinglet — minimum buffer width to sustain 60 197 Darveau et al 1995 Knutson and Naef 1997 Swainson's Thrush — minimum buffer width to sustain 60 197 Darveau et al 1995 Knutson and Naef 1997 Brown Thrasher 100 330 Cohen 1997 Ellis and Richard 2008 American Redstart — minimum mean width to support breeding populations of American Redstarts 200 656 Staufferand Best 1980 Knutson and Naef 1997 Spotted Towhee — minimum mean width to support breeding populations of Spotted Towhees 200 656 Staufferand Best 1980 Knutson and Naef 1997 Red-winged Blackbird — foraging dis- tance from nests in wetlands 200 656 Short 1985 Knutson and Naef 1997 15 Scientific Recommendations on the Sizeof Stream Vegetated Buffers Needed to Protect Wildlife and Wildlife Habitat ..,,a^i.— , General Habitat for Mammals ^^m Mammal habitat >50 >164 Dickson 1989 Fisher et al 2000 Large mammals — recommended riparian buffer for large mammals lOO 328 Jones etal 1988 Knutson and Naef 1997 Small mammals — recommended riparian buffer width for small mam- mals 67-93 220-305 Jones etal 1988 Knutson and Naef 1997 Small mammals — diversity and species composition similar to undis- turbed sites 67 220 Cross 1985 Wenger 1999 Small mammals — no small mammal species lost 12-70 39-230 Cross 1985 Knutson and Naef 1997 Mammal — Species Information ^^ ^^^ w Dusky shrew — food and cover 183 600 Clothier 1955 Knutson and Naef 1997 Bats — average minimum distance between roost sites and streams for two Montana bat species 90 295 Schwab 2002 Beaver — majority of foraging 100 328 Allen 1983 Knutson and Naef 1997 Beaver foraging: 30 meters = 90% foraging distance for beaver; loo meters = maximum foraging distance (but 200 meters has been reported) 30-100 100-328 Allen 1983, Hall 1970 Knutson and Naef 1997 Muskrat 100 330 Cohen 1997 Ellis and Richard 2008 Carnivores ^^^^^H Mink will not use areas farther than 200 meters from water 200 656 Melquist etal 1981 Knutson and Naef 1997 Mink — riparian buffer needed for dens, cover, and forage 100 328 Melquist etal 1981, Allen 1986b Knutson and Naef 1997 Mink — buffer area of optimum cover and forage habitat 100 328 Allen 1986b Knutson and Naef 1997 Otter 100 330 Cohen 1997 Ellis and Richard 2008 Fisher travel corridor — needed on each side of stream to provide a 600 foot travel corridor in mature uncut basins for fisher 91 300 Freel 1991 Knutson and Naef 1997 Fisher use 100 328 Small 1982 Knutson and Naef 1997 Pine Marten — vegetation within this distance used by marten as travel cor- ridor and habitat 100 328 Small 1982 Knutson and Naef 1997 Pine Marten — food and cover 61 200 Spencer 1981 Knutson and Naef 1997 16 Scientific Recommendations on the Sizeof Stream Vegetated Buffers Needed to Protect Wildlife and Wildlife Habitat 1 Author of Origin) Scientific Study J ^■le of Review 1 Carnivores (continued) ^^K 1 ' ^^^^^^B J Pine Marten — provides travel cor- ridors for marten when buffers are on both sides of streams in mature uncut basins (total buffer is g^ meters) 46 151 Freel 1991 Knutson and Naef 1997 Bobcat 100 330 Cohen 1997 Ellis and Richard 2008 Red fox — Vegetation within this distance used by red fox as travel cor- ridor and habitat 100 328 Small 1982 Knutson and Naef 1997 Eil( and Deer 1 Eil( calving grounds are usually within this distance of water 305 1,000 Thomas 1979 Knutson and Naef 1997 Deer and e\k cover — distance hid- ing cover needed at 90% vegetative cover 61 200 Muddi975 Knutson and Naef 1997 Deer — riparian buffer needed by deer in eastern Washington 23 75 Mudd 1975 Knutson and Naef 1997 Appendix II References Cited All scientific studies that appear in this report are cited below: Allen, A. W. 1983. Habitat suitability index mod- els: beaver. U.S. Fish and Wildl. Serv., FWS/ OBS-82/10.30. Wash., D.C. 20 pp. (from Knut- son and Naef 1997) . 1986a. Habitat suitability index models: lesser scaup (breeding). U.S. Fish and Wildl. Serv., FWS/OSB-82/10.117. Fort Collins, Colo. 16 pp. (from Knutson and Naef 1997) . 1986b. Habitat suitability index mod- els: mink. Biol. Rep. 82 (10.127). Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service. 23 pp. (from Knutson and Naef 1997) Bottom, D. L., P. J. Howell, and J. D. Rodgers. 1983. Final report: fish research project Oregon sal- monid habitat restoration. Oreg. Dept. Fish and WUdl., Portland,. 155 pp. (from Knutson and Naef 1997) Bowman, I., and J. Siderius. 1984. Management guidelines for the protection of heronries in Ontario. Wildl. Branch, Ontario Minist. Nat. Resour., Toronto, (from Knutson and Naef 1997) Brosofske, K. D., J. Chen, R. J. Naiman, and J. F. Franklin, 1997. Harvesting effects on microcli- mate gradients from small streams to uplands in western Washington. Ecological Applica- tions 7:1188-1200. (from Fischer et al 2000) 17 Scientific Recommendations on the Sizeof Stream Vegetated Bulgers Needed to Protect Wildlife and Wildlife Habitat Buhlmann, K. A, 1998. Ecology, Terrestrial Habitat Use, and Conservation of a Freshwater Turtle Assemblage Inhabiting a Seasonally Fluctuat- ing Wetland with Emphasis on the Life History of Deirochelys reticularia. Ph.D. Dissertation, University of Georgia, Athens. 176 pp. (from Fischer et all 2000) Burbrink, R T, C. A. Phillips, and E. J. Heske. 1998. A riparian zone in southern Illinois as a potential dispersal corridor for reptiles and amphibians. Biological Conservation 86:107-115. (from Wenger 1999; Fischer et al 2000) Burke, V. J. and J. W. Gibbons. 1995. Terrestrial buf- fer zones and wetland conservation: A case study of freshwater turtles in a Carolina Bay. Conservation Biology 9(6):i365-i369. (from Wenger, 1999) Cassirer, E. R, and C. R. Groves. 1990. Distribution, habitat use, and status of harlequin ducks in northern Idaho. ID. Fish and Game, Boise. 55 pp. (from Knutson and Naef 1997) Chen, J., J. R Franklin, and T A. Spies. 1990. Micro- climatic pattern and basic biological responses at the clearcut edges of old-growth Douglas-fir stands. Northwest Environ. J. 6:424-425. (from Knutson and Naef 1997) Clothier, R. R. 1955. Contribution to the life his- tory of Sorex vagrans in Montana. J. Mamm. 36:214-221. (from Knutson and Naef 1997) Cohen, Russell. 1997. Fact Sheet 4: Buffers for Habi- tat. Fact Sheet Series on Function and Value of Riparian Areas. Massachusetts Depart- ment of Fisheries, Wildlife and Environmental Law Enforcement; September 5, 1997, 6 pages. Accessed May 26, 2008; at URL . (From Ellis and Richard 2008) Conner, R. N., R. G. Hooper, H. S. Crawford, and H. S. Mosby. 1975. Woodpecker nesting habitat in cut and uncut woodlands in Virginia. J. Wildl. 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Anderson. 1987. Multiscale associations between cavity-nesting birds and features of Wyoming streamside woodlands. Condor 89:534. (from Knutson and Naef 1997) Scientific Recommendations on the Sizeof Stream Vegetated Bulgers Needed to Protect Wildlife and Wildlife Habitat Hall, J. G. 1970. Willow and aspen in the ecology of beaver in Sagehen Creek, California. Ecology 41:484-494. (from Knutson and Naef 1997) Maine. Maine Dept. Inland Fish, and WUdl., Augusta. 140 pp. (from Knutson and Naef 1997)) Hagar, J. C, 1999. Influence of riparian buffer width on bird assemblages in western Oregon. Jour- nal of Wildlife Management 63:484-96. (from Fischer 2000; Fischer et al 2000) Harmon, M. E., J. F. Franklin, F. J. Swanson, P. Sollins, J. D. Gregory, J. D. Lattin, N. H. Anderson, S. P. Cline, N. G. Aumen, J. R. Sedell, G. W Lien- kaemper, K. Cromack Jr., and K. W Cummins. 1986. Ecology of coarse woody debris in tem- perate ecosystems. Adv. Ecol. Res. 15:133-302. 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A review of the scientific lit- erature on riparian buffer width, extent and vegetation. Athens: Institute of Ecology Office for Public Service and Outreach, University of Georgia. 59 pp. 23 Scientific Recommendations on the Sizeof Stream Vegetated Bulgers Needed to Protect Wildlife and Wildlife Habitat Whitaker, D. M., and W. A. Montevecchi, 1999. Breeding bird assemblages inhabiting riparian buffer strips in Newfoundland, Canada. Jour- nal of Wildlife Management 63:167-79. (from Fischer 2000; Fischer et al 2000) Zarn, M. 1974. Osprey (Pandion haliaetus caro- linensis). Habitat Manage. Ser. for Unique or Endangered Species Rep. #12, U.S. Bur. Land Manage. 41pp. (from Knutson and Naef 1997) Zeigler, B. C. 1992. Buffer needs of wetland wild- life. Wash. Dept Wildl., Olympia. 54pp. {from Knutson and Naef 1997) Acknowledgements A special thanks goes to the following indi- viduals who provided advice, editorial counsel, and support for this publication: Chris Clancy, Kristi DuBois, Allison Begley, and Doris Fischer (FWP); Lynda Saul (DEQ); and Amy Cilimburg and Steve Hoffman (Montana Audubon). Geoff Wyatt, of Wyatt Design, designed the report and developed the illustration on page 3. Rick Newby, Zadig, LLC, copyedited the text. Financial support for this report came from the Montana Dept. of Environmen- tal Quality (DEQ); U.S. Environmental Protection Agency; Montana Fish, Wildlife & Parks (FWP); the Liz Caliborne/Art Ortenberg Foundation; and Montana Audubon. 24