Riparian Buffers

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Riparian buffers are a legal designation of land around a stream or river, where the condition of that land is regulated to protect the stream or river. Riparian buffers are proscribed in a wide range of federal, state, and local laws, such as the Endangered Species Act and Shoreline Management Act, and are an important concern of Tribal Governments seeking to protect treaty rights. Contention around who controls the condition of buffers and who pays for restoration have been a long-standing source of conflict between rights-holders, and interest groups. A series of efforts, documents, and a lesser-known history of political negotiations are central to buffer regulation.

"To buffer" is an verb. A "buffer" is a regulatory designation of an area were management is changed near a stream to reduce the potential negative impacts of proximate land uses like forestry, agriculture or residential development. On the other hand, "riparian functions" are those dynamics observed in historical systems (i.e. evolved over long periods of time, and to which biota are adapted) that support biota directly or indirectly--many of these functions involve environmental buffering. Buffering functions are varied and complex, and could be divided into two general groups:

Washington Chronology

• 1987 - The Timber Fish and Wildlife Agreement defines stewardship of stream corridors under forest practices, setting the stage for expanding the buffer debate to other sectors of land use File:TFW 1987 timber fish and wildlife agreement.pdf.
• 1996 - NOAA 1996 defines the concept of "properly functioning conditions" as part of salmon recovery planning policies.
• 1997 - Knutson & Naef 1997 provides a milepost in best available science for riparian zones by WDFW.
• 1999 - The listing of Chinook Salmon under the Endangered Species Act elevates buffer condition as a key element of Salmon Recovery Planning.
• 2000?? - Tri-County negotiations conclude
• 2002 - Initial publication of a draft buffer table during the Ag Fish and Water Negotiations describes tree height as a basis for buffer width. Those negotiations did not lead the substantive change in policy.
• 2011 - Publication of the Treaty Rights at Risk whitepaper by a tribal consortium (File:NWIFC 2011 treaty rights at risk.pdf) refocuses attention on unresolved issues affecting fisheries.
• 2011 - Washington Legislature authorizes the Voluntary Stewardship Program that creates an alternate pathways by which Local Jurisdictions can implement Critical Areas Regulation on Agricultural lands, through a voluntary improvement process.
• 2015 - EPA funded team at Ecology initiates the Riparian Restoration and Protection Initiative
• 2015 - Dittbrenner et al 2015 makes an argument for obtaining variable function from multi-purpose buffers, and raises the question of concentrated flows.
• 2020 - WDFW updates the best available science in a two volume publication beginning with a science synthesis in Quinn et al 2020 and policy recommendations by Windrope et al 2020.
• 2022 - The Loraine Loomis Act dies in committee, which would have required restoration of agricultural buffers.
• 2022 - Kubo et al 2022 as part of the Snoqualmie Fish, Farm & Flood Initiative begins to separate functional objectives based on buffer context.

Notes

• The size and character of stream-side land necessary for buffing reflects a combination of the social consensus that these functions have value, and the degree to which proximate land uses create a threat that demands buffering.
• All buffer functions are often lumped in political discussions of buffer regulation. Buffer width is the most commonly debated factor (File:Johnson & Ryba 1992 king county recommendations for buffer width.pdf; Knutson & Naef 1997; GEI 2002; Varanasi 2003).
• Buffer function management has implications for forest management most commonly in headwater valleys. This management is defined in the Forest Practices Act as implemented by WDNR in consultation with Tribal Governments and WDFW, strongly affected by the Timber Fish and Wildlife Agreement.
• Agricultural landscapes often associated with floodplains, are a current (2014) focus of buffer management conflict, as agricultural land preservation and property rights interest groups compete legally and politically with salmon recovery and water quality interest groups over who has the authority and responsibility to manage buffer conditions.
• In urbanizing landscapes often associated with lowland watersheds, issues around riparian buffer functions are often eclipsed by impervious surface effects, which drive stream condition through modification of stream flow. Any analysis of buffer function in a given system is likely to be dependent on analysis of watershed hydrology, such that deforestation, impervious surfaces and groundwater withdrawal has effects on stream conditions that cannot be offset by increasing buffer function.
• Buffer management debate in the Salish Sea has been driven by Endangered Species Act and the effects of riparian conditions on salmon, and pathogen impacts on shellfish harvest, and water quality designation under the Clean Water Act.

Buffer Function

Different authorities and analyses use different language and lump and split in different ways to describe the functions of buffers.

Geomorphic and bioenergetic processes:

• Habitat islands or corridors for species that depend on rivers and streams
• Habitat corridors for terrestrial species (that otherwise have no habitat due to development)
• Shading effects on microclimate and stream temperature
• Organic litter inputs to stream ecosystems
• Large wood and rootwad effects of stream structure

Biochemical and water quality processes:

• Nutrient and sediment removal and sequestration (in soils and biomass, with harvest providing removal)
• Denitrification (as a nitrogen removal pathway) particularly in anaerobic soils.
• Pathogen removal (livestock and pet waste).
• Toxin decomposition and sequestration (pesticides, transportation runoff?)

Interesting Focused Efforts

• Snoqualmie Fish, Farm and Flood Initiative is a multi-stakeholder effort to define riparian zone strategies for the Snoqualmie Agricultural Production District, including variable width buffers.
• The NEP program funded the Stormwater SIL (at Ecology) to complete an intensive experiment in riparian buffer restoration called the Riparian Restoration and Protection Initiative. Their final presentation (Hume & Bush 2020) provides a range of insights into the riparian zone management challenge.
• WDFW as the states science agency for habitat recently updated its riparian analysis, culminating in management recommendations Windrope et al 2020

Documents AFW 2002 federal riparian buffer matrix Benedict & Shaw 2012 shade benefits from hedgerow on ditched streams Boggs & Corey 2009 whatcom drainage maintenance guidance Carr et al 2014 snohomish landowner buffer preference survey Christensen 2000 jefferson county riparian best available science Cramer et al 2012 stream habitat restoration guidelines Crawford 2011 riparian restoration effectiveness monitoring Dittbrenner et al 2015 working buffers analysis Flint 2012 woods creek riparian action plan GEI 2002 agricultural riparian buffers Hume & Bush 2020 final report riparian protection restoration Johnson & Ryba 1992 king county recommendations for buffer width Knutson & Naef 1997 riparian management recommendations Kubo et al 2019 snoqualmie riparian buffer best science LeDoux & Kubo 2020 snoqualmie riparian buffer task force final report May 2003 riparian best available science puget lowland File:PNRS 2013 effects of timber thinning on habitat.pdf Rentz et al 2020 WDFW riparian management recommendations File:Varanasi 2003 buffer critique GEI report.pdf File:Zobrist et al 2004 riparian forest management templates.pdf

Other Pages Cereghino 2024 draft riverscape agroforestry principles Integrated Riverscape Management Loraine Loomis Act Puget Sound Marine Riparian Mapping Riparian Data Engine Riparian Restoration and Protection Initiative Scatter Creek Farm and Conservancy Sno-Stilly Riparian Zone Management Strategy Snoqualmie Fish, Farm & Flood Initiative Stream Temperature and Salmon Voluntary Clean Water Guidance for Agriculture Voluntary Stewardship Program Watershed Research Cooperative Western Washington Riparian Workgroup Whatcom Drainage Maintenance Guidance Working Buffer Pilot Project

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particles of clay, silt, sand, gravel, or cobble, transported by water, are called sediment.