title: Projecting cumulative benefits of multiple river restoration projects: an example from the Sacramento-San Joaquin River system in California.
abstract: Despite increasingly large investments, the potential ecological effects of river restoration programs are still small compared to the degree of human alterations to physical and ecological function. Thus, it is rarely possible to "restore" pre-disturbance conditions; rather restoration programs (even large, well-funded ones) will nearly always involve multiple small projects, each of which can make some modest change to selected ecosystem processes and habitats. At present, such projects are typically selected based on their attributes as individual projects (e.g., consistency with programmatic goals of the funders, scientific soundness, and acceptance by local communities), and ease of implementation. Projects are rarely prioritized (at least explicitly) based on how they will cumulatively affect ecosystem function over coming decades. Such projections require an understanding of the form of the restoration response curve, or at least that we assume some plausible relations and estimate cumulative effects based thereon. Drawing on our experience with the CALFED Bay-Delta Ecosystem Restoration Program in California, we consider potential cumulative system-wide benefits of a restoration activity extensively implemented in the region: isolating/filling abandoned floodplain gravel pits captured by rivers to reduce predation of outmigrating juvenile salmon by exotic warmwater species inhabiting the pits. We present a simple spreadsheet model to show how different assumptions about gravel pit bathymetry and predator behavior would affect the cumulative benefits of multiple pit-filling and isolation projects, and how these insights could help managers prioritize which pits to fill.
authors.affiliation: Department of Landscape Architecture and Environmental Planning, University of California, Berkeley, 202 Wurster Hall #2000, Berkeley, CA 94720-2000, USA. kondolf@berkeley.edu
authors.forename: G Mathias
authors.initials: GM
authors.lastname: Kondolf
authors.forename: Paul L
authors.initials: PL
authors.lastname: Angermeier
authors.forename: Kenneth
authors.initials: K
authors.lastname: Cummins
authors.forename: Thomas
authors.initials: T
authors.lastname: Dunne
authors.forename: Michael
authors.initials: M
authors.lastname: Healey
authors.forename: Wim
authors.initials: W
authors.lastname: Kimmerer
authors.forename: Peter B
authors.initials: PB
authors.lastname: Moyle
authors.forename: Dennis
authors.initials: D
authors.lastname: Murphy
authors.forename: Duncan
authors.initials: D
authors.lastname: Patten
authors.forename: Steve
authors.initials: S
authors.lastname: Railsback
authors.forename: Denise J
authors.initials: DJ
authors.lastname: Reed
authors.forename: Robert
authors.initials: R
authors.lastname: Spies
authors.forename: Robert
authors.initials: R
authors.lastname: Twiss
mesh_terms: D000818:Animals; D000835:Animals, Wild; D002140:California; D003247:Conservation of Natural Resources; D017753:Ecosystem; D004777:Environment; D019015:Geologic Sediments / Q000032:analysis*; D006801:Humans; D008954:Models, Biological; D011235:Predatory Behavior; D045483:Rivers; D012474:Salmon / Q000502:physiology*; D014872:Water Movements; D014881:Water Supply