File:Kubo et al 2019 snoqualmie riparian buffer best science.pdf

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Kubo, J., M. Thai, K. Higgins, B. leDoux. 2019. Synthesis of Riparian Best Available Science to Inform Variable-Width Buffers in the Lower Snoqualmie Valley. Prepared by King County, Water and Land Resources Division. Seattle, Washington. 97 pp.


  • Developed in support of the Snoqualmie Fish, Farm Flood Initiative to evaluate options within the Snoqualmie Valley Agricultural Production District.
  • Identifies a set of "buffer characteristics" such as: width, length, tree size (sometimes referred to as "composition"), connectivity
  • Identifies six "habitat functions": water quality (including nutrients, sediment and pollution), water temperature, microclimate, large wood, erosion and bank stability, and invertebrate prey and leaf-litter detritus.
  • The analysis focuses on the effects of the presence of stream-side vegetation, but not other strategies for increasing ecosystem services such as interception of runoff, or increased channel complexity.
  • Authors report that development of a 150 foot buffer would result in a loss of 2,400 acres of farmed land, a 1/4 reduction in farmed area in the Snoqualmie APD.
  • This analysis was built from key WDFW resources: Quinn et al 2020 and Rentz et al 2020 which generally say "bigger is better" but aims to isolate how different buffer characteristics affect different functions.
  • Historically the valley bottom had large areas of shrub-scrub wetlands with perhaps 20% cedar and spruce. Natural levees were mostly hardwood, but with large conifers intermixed.
  • Both estuary rearing and river rearing life histories of Chinook are present in the Snoqualmie, but appear to stay in channel margins, as they may be competitively displaced by coho rearing in off channel areas. River-rearing appears to increase ocean return Beamer et al 2005.


  • Function is delivered at a large scale than an individual buffer patch. How are characteristics at larger scales considered in patch design?
  • Does the analysis provide a basis for monitoring and adaptive management.
  • The analysis suggests on p27 "Reestablishing riparian vegetation along watercourses is the primary method used to protect and improve water quality in rural

areas, where open channels are the primary method of surface water movement." However the water quality concerns described in Joy 1994 are for Temperature, pH, nutrients, DO, and Fecal. Nutrients could be presumed to be a driver, by affecting DO and pH. Fecal likely co-occurs with animal-source nutrient inputs, which are abundant. Does riparian restoration represent a coherent response to the specific challenges to water quality.

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current18:34, 12 April 2023 (2.25 MB)Pcereghino (talk | contribs)

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