The Science of Stream Buffers Lake George Stream Corridor Management Stakeholder Meeting

The Science of Stream Buffers

• Lake George Stream Corridor Management Stakeholder Meeting

• May 28, 2008

About the Center for Watershed Protection

• Non-profit 501(c)3, non-advocacy organization

• Work with watershed groups, local, state, and federal governments

• Provide tools communities need to protect streams, lakes, and rivers

• 20 staff in Ellicott City, MD and satellite Offices

• www.cwp.org

• www.stormwatercenter.net

Small Streams

• Effective at processing nutrients

• Most frequently disturbed during the development process

Basics of Stream Buffers

• Stream buffers are more than a line on a map

• It is more than a setback

• The floodplain is the core of the buffer

• Management is just as important as width

• Should be continuous

• Gaps can introduce additional surface flow

Benefits of Stream Buffers

• Environmental Economic / Community

Environmental Benefits

Temperature

• Many coldwater fish species have limited temperature range tolerance (e.g., trout)

• Stream warming from is caused by a variety of factors:

• Loss of riparian cover (air temp in headwater streams)
• Impervious surfaces
• Stormwater ponds

• 60% riparian forest cover retains temperature

• 80% riparian forest lowers temperature

Sediment

Phosphorus

Economic/Community Benefits

Stream Buffer Design

• Preferred widths

• Sediment removal
• Phosphorus/Nitrogen removal

• Special resource/protection areas

• Three-zone buffer design

• Allowable uses

Buffer Widths and Pollutant Removal

Special Resource/Protection Areas

• Base width should be expanded to include:

• Ultimate 100 year floodplain
• Very steep slopes greater than 25%

• Wetlands, critical habitats and forest conservation areas should have larger buffers

Three-Zone Buffer Design

• Each zone has different function, width, vegetative target, and management:

• Streamside zone: 25 feet of undisturbed forest cover
• Middle zone: 50 feet or more of managed forest
• Outer zone: 25 feet of grass or forest setback from structures

Stream Buffer Crossings

• To minimize fish blockages, all crossings should follow these guidelines:

• Width: minimum right of way needed for access
• Angle: perpendicular to stream
• Frequency: no more than one crossing/1000 feet
• Depth: utilities three feet below streambed
• Capacity: convey 100 year storm
• Culverts: bottomless, slab, arch or box designs preferred

Stream xing photo

Riparian Buffer Management

Riparian Buffer Management

Recommended Reading

• Emmons and Olivier Resources. Benefits of Wetland Buffers: A Study of Functions, Values and Sizes. http://www.minnehahacreek.org/documents/MCWD_Buffer_Study.pdf

• Meyer, J.L. and J.B. Wallace. 2001. Lost linkages and lotic ecology: rediscovering small streams. http://cwt33.ecology.uga.edu/publications/1444.pdf

• Sweeney, B.W., T.L. Bott, J.K. Jackson, L.A. Kaplan, J.D. Newbold, L.J. Standley, W.C. Hession, and R.J. Horwitz. 2004. Riparian Deforestation, Stream Narrowing, and Loss of Stream Ecosystem Services. Proceedings of the National Academy of Sciences 101(39):14132-14137. http://www.stroudcenter.org/about/pdfs/bs_PNAS092804.pdf

• Wenger, S. 1999. A review of the scientific literature on riparian buffer width, extent, and vegetation. Publication of the Office of Public Service and Outreach, Institute of Ecology, University of Georgia. 58pp.