HR: 1340h
AN: H13E-1362    [Abstracts]
TI: Constraints and Opportunities for Rehabilitation of an Urban, Sonoran Desert River
AU: White, J
EM: Jackie.White@asu.edu
AF: School of Life Sciences Arizona State University, PO Box 874501, Tempe, AZ 85287
AU: * Stromberg, J
EM: jstrom@asu.edu
AF: School of Life Sciences Arizona State University, PO Box 874501, Tempe, AZ 85287
AU: Poznik, J
EM: Jenica.Poznik@asu.edu
AF: School of Life Sciences Arizona State University, PO Box 874501, Tempe, AZ 85287
AU: White, M
EM: Meg.White@asu.edu
AF: School of Life Sciences Arizona State University, PO Box 874501, Tempe, AZ 85287
AB: Several riparian restoration projects are underway in the arid southwestern United States, many centered on urban rivers. In the Phoenix metropolitan area (Arizona), multiple projects are ongoing or planned along the Salt River. Several factors constrain the urban Salt River projects: the occasional surface flows released from the upstream diversion dam are no longer hydraulically connected to the deepened groundwater table in all reaches; upstream diversion and flow-regulating dams create barriers to the flow of fine sediments, seeds and other materials; channelization has disconnected the river from its historic floodplain; and many of the tributary-mainstem connections have been severed. Actions are not being undertaken to reverse these changes; rather, attempts are being made to create localized oases by transporting pumped groundwater via delivery channels to sustain trees planted at the termini of drip-irrigation lines, and by re-shaping the land surface to create ponds and perched aquifers. In addition to these planned restorations, pockets of riparian vegetation have developed naturally along the Salt River in areas where new urban water sources have become available. We are investigating the diversity and dynamics of these self-assembled plant communities, and comparing them to the areas of focused restoration as well as to regional free-flowing reference rivers. Analysis indicates that input of water from urban storm drains sustains a diverse (but spatially limited) riparian plant community along the Salt River, albeit one whose composition reflects, in part, the urbanized landscape and thus deviates from the palette of the intended restoration plantings. In effect, the urban storm drains are functioning as tributaries and connecting the river with its watershed. The new riparian ecosystems at these storm drain outflows and at the planned restoration areas will inevitably differ from those at regional reference rivers, unless historical ecosystem processes, connections, and landscape settings are restored, an unlikely occurrence in this and most urban settings.
DE: 1813 Eco-hydrology
DE: 1820 Floodplain dynamics
DE: 1851 Plant ecology (0476)
SC: Hydrology [H]
MN: Fall Meeting 2005