Portland State University PDXScholar Environmental Science and Management Faculty Publications and Presentations Environmental Science and Management 12-31-2010 Urban and Rural-residential Land Uses: Their Role in Watershed Health and the Rehabilitation of Oregon’s Wild Salmonids Michael Harte Oregon State University Victor W. Kaczynski Clinton C. Shock Oregon State University J. Alan Yeakley Portland State University, [email protected] Robert M. Hughes Oregon State University Follow this and additional works at: https://pdxscholar.library.pdx.edu/esm_fac See next page for additional authors Part of the Environmental Health and Protection Commons, Sustainability Commons, and the Water Resource Management Commons Let us know how access to this document benefits ou.y Citation Details Independent Multidisciplinary Science Team (2010) Urban and Rural-residential Land Uses: Their Roles in Watershed Health and the Recovery of Oregon’s Wild Salmonids. Technical Report 2010-1.Oregon Plan for Salmon and Watersheds, Oregon Watershed Enhancement Board. Salem, Oregon. This Technical Report is brought to you for free and open access. It has been accepted for inclusion in Environmental Science and Management Faculty Publications and Presentations by an authorized administrator of PDXScholar. Please contact us if we can make this document more accessible: [email protected]. Authors Michael Harte, Victor W. Kaczynski, Clinton C. Shock, J. Alan Yeakley, Robert M. Hughes, Nancy Molina, and Carl B. Schreck This technical report is available at PDXScholar: https://pdxscholar.library.pdx.edu/esm_fac/66 Urban and Rural-residential Land Uses: Their Role in Watershed Health and the Rehabilitation of Oregon’s Wild Salmonids IMST Technical Report 2010-1 Released December 31, 2010 Independent Multidisciplinary Science Team Members: Oregon Plan for Salmon and Watersheds Michael Harte Robert M. Hughes http://www.fsl.orst.edu/imst Vic Kaczynski Nancy Molina Clinton Shock Carl Schreck Alan Yeakley Citation Independent Multidisciplinary Science Team (2010) Urban and Rural-residential Land Uses: Their Roles in Watershed Health and the Recovery of Oregon’s Wild Salmonids. Technical Report 2010-1.Oregon Plan for Salmon and Watersheds, Oregon Watershed Enhancement Board. Salem, Oregon. Acknowledgements This IMST report is based on initial draft documents prepared by current and previous IMST subcommittees* that included Robert M. Hughes, Alan Yeakley, Carl Schreck, Michael Harte, Stan Gregory, Logan Norris, and Jim Lichatowich. The subcommittee that managed the final draft of the report was composed of Alan Yeakley, Robert M. Hughes, and Carl Schreck with significant support by Kathy Maas-Hebner. Subcommittees received significant support from OSU Faculty Research Assistants*, Susie Dunham, Kathy Maas-Hebner, Ellen Deehan, Leah Gorman, and Cathleen Rose during development of this report. Additional directions and comments were made by the following Team members including John Buckhouse, Neil Christensen, Wayne Elmore, Victor Kaczynski, Katy Kavanagh, Nancy Molina, William Pearcy, Clinton Shock, and Carlton Yee. Additional technical and scientific support was provided by Ben Clemens, Jennifer Gervais, and Dan McGarvey. IMST solicited materials and information from a wide array of agencies within Oregon’s urban areas, and from a few urban areas in Washington and northern California. In addition, the Team received briefings from technical staff from the City of Portland, Metro, Portland Audubon, King County (Washington), the Willamette Urban Watershed Network, NOAA Fisheries, NOAA National Ocean Services, Oregon DLCD, and Oregon DEQ. A draft of the report was peer reviewed by the following scientific and technical specialists: Derek Booth, Jay Charland, Tracy Collier, Derek Godwin, Teresa Huntsinger, Jeff Kline, Kevin Masterson, Mike Meador, Judy Meyer, Logan Norris, Amanda Punton, Adam Stebbins, Josh Seeds, Don Yon, and Doug Drake. Portions of the final draft were unanimously adopted at the September 20 and October 28, 2010 IMST public meetings. * Areas of major contributions by subcommittee members and staff were: Introduction – S. Dunham, K. Maas-Hebner, L. Gorman, C. Rose; Science Question 1 – R. M. Hughes, S. Gregory, J. Lichatowich, L. Norris, C. Schreck, A. Yeakley, S. Dunham, K. Maas-Hebner, E. Deehan, L. Gorman, C. Rose; Science Question 2 – M. Harte, S. Dunham, L. Gorman; Science Question 3 – R. M. Hughes, K. Maas-Hebner, E. Deehan; Science Question 4 – R. M.. Hughes, M. Harte, A. Yeakley. Urbanization and Oregon’s Wild Salmonids Executive Summary This technical report by the Independent Multidisciplinary Science Team (IMST) is a comprehensive review of how human activities in urban and rural-residential areas can alter aquatic ecosystems and resulting implications for salmonid recovery, with a geographic focus on the state of Oregon. The following topics are considered in the form of science questions, and comprise the major components of this report: 1) The effects of urban and rural-residential development on Oregon’s watersheds and native wild salmonids. 2) Actions that can be used to avoid or mitigate undesirable changes to aquatic ecosystems near developing urban and rural-residential areas. 3) The benefits and pitfalls of salmonid habitat rehabilitation within established urban or rural-residential areas. 4) Suggested research and monitoring focus areas that will facilitate the recovery of salmonid populations affected by development. The fundamental concepts presented in this report should be applicable to most native salmonid populations across the state. IMST encourages managers and policy-makers with interest in a specific species or geographic region to carefully research local ecological conditions, as well as specific life history characteristics of salmonids in the region. Conserving watershed condition and salmonids in the face of increasing development requires consideration of two distinct sets of processes. First are the human social and economic processes that drive patterns in land use change. Second are the ecological processes, altered by land use, that underlie salmonid habitat changes. This report focuses on the latter and summarizes the effects of rural-residential and urban development on native, wild salmonid populations and the watersheds upon which they depend. GENERAL EFFECTS OF URBANIZATION The pressures of urban and rural residential land use affect aquatic ecosystems and salmonids through alterations of, and interactions among, hydrology, physical habitat structure, water quality, and fish passage. These alterations occur at local and, especially, watershed scales, and thus require study and management at multiple scales. Urban and rural-residential development causes profound changes to the pathways, volume, timing, and chemical composition of stormwater runoff. These changes alter stream physical, chemical, and biological structure and potential, as well as the connectivity of streams with their watersheds. Although some authors have reported effect or no-effect thresholds between percent urbanized or impervious watershed and biological or hydrological responses, IMST uncovered no evidence of consistent thresholds in its examination of results presented in the scientific literature. Urbanization generally results in the urban stream syndrome, marked both by increases in peak flows in streams, in channel erosion, and in non-native and tolerant species abundances, and by decreases in base flows in streams, in channel and physical habitat complexity, in physical and chemical water quality, in fish passage, and in intolerant species. The result of all these changes associated with the urban stream syndrome is a decline in overall biological condition. The magnitudes and rates of those i Urbanization and Oregon’s Wild Salmonids changes vary with prior land use and natural geographic or ecoregional factors (i.e., climate, geology, landform, soils, and natural vegetation). RESEARCH AND MONITORING NEEDS There are many research and monitoring needs directly related to urban and rural residential areas, some of which overlap with the research and monitoring needs for other land use types. Given the marked effects of developed areas on surface waters, the continued expansion of development in Oregon, the proportion of the human population residing in these areas and the limited amount of research and monitoring conducted on them, IMST believes that the following research and monitoring needs warrant greater attention from Oregon Plan agencies. Better knowledge is needed on the general effects of urban development, including the major factors that impair aquatic ecosystems and limit salmonid populations in urban and rural residential areas. Specifically, there are needs to: 1) Assess how effective impervious area (including its proximity and connectivity to streams), landscape development indices, and measures of traffic or road density affect aquatic ecosystem responses to varying degrees. 2) Insure that research on water quality (e.g., toxic chemicals) is integrated into other inter- related factors that affect entire aquatic ecosystems (i.e., from headwaters to estuaries and near-shore marine environments) for salmonid recovery. 3) Consider large-scale, long-term changes and anticipate at least 50-100 years of human population and economic growth on salmonid-supporting watersheds, through the use of futuring and systematic analyses. Better knowledge is needed on the variation of effects of development across Oregon, including