Process-Based Ecological River Restoration: Visualizing Three-Dimensional Connectivity and Dynamic Vectors to Recover Lost Linkages
G. Mathias Kondolf,
University of California, BerkeleyAndrew J. Boulton,
Ecosystem Management, University of New EnglandScott O'Daniel,
University of California-Santa BarbaraGeoffrey C Poole,
Eco-metrics, Inc. and University of GeorgiaFrank J. Rahel,
University of WyomingEmily H. Stanley,
University of WisconsinEllen Wohl,
Colorado State UniversityAsa Bång,
Mid Sweden UniversityJulia Carlstrom,
National Board of FisheriesChiara Cristoni
Harald Huber,
University of MunichSaija Koljonen,
University of Jyväskylä, Department of Biological and Environmental SciencePauliina Louhi,
Finnish Game and Fisheries Research InstituteKeigo Nakamura,
Public Works Research Institute, Japan
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Abstract
Human impacts to aquatic ecosystems often involve changes in hydrologic connectivity and flow regime. Drawing upon examples in the literature and from our experience, we developed conceptual models and used simple bivariate plots to visualize human impacts and restoration efforts in terms of connectivity and flow dynamics. Human-induced changes in longitudinal, lateral, and vertical connectivity are often accompanied by changes in flow dynamics, but in our experience restoration efforts to date have more often restored connectivity than flow dynamics. Restoration actions have included removing dams to restore fish passage, reconnecting flow through artificially cut-off side channels, setting back or breaching levees, and removing fine sediment deposits that block vertical exchange with the bed, thereby partially restoring hydrologic connectivity, i.e., longitudinal, lateral, or vertical. Restorations have less commonly affected flow dynamics, presumably because of the social and economic importance of water diversions or flood control. Thus, as illustrated in these bivariate plots, the trajectories of ecological restoration are rarely parallel with degradation trajectories because restoration is politically and economically easier along some axes more than others.
Key words
connectivity; flow dynamics; hyporheic zone; river restoration.
Ecology and Society. ISSN: 1708-3087