Origin of Stream Flows at the Wildlands-Urban Interface, Santa Monica Mountains, California, U.S.A

Research Article| February 01, 2012 Origin of Stream Flows at the Wildlands-Urban Interface, Santa Monica Mountains, California, U.S.A BARRY J HIBBS; BARRY J HIBBS 1 Department of Geological Sciences, California State University, 5151 State University Drive, Los Angeles, CA 90032 1Corresponding author email: bhibbs@calstatela.edu. Search for other works by this author on: GSW Google Scholar WYNEE HU; WYNEE HU Department of Geological Sciences, California State University, 5151 State University Drive, Los Angeles, CA 90032 Search for other works by this author on: GSW Google Scholar RACHEL RIDGWAY RACHEL RIDGWAY Department of Geological Sciences, California State University, 5151 State University Drive, Los Angeles, CA 90032 Search for other works by this author on: GSW Google Scholar Author and Article Information BARRY J HIBBS 1 Department of Geological Sciences, California State University, 5151 State University Drive, Los Angeles, CA 90032 WYNEE HU Department of Geological Sciences, California State University, 5151 State University Drive, Los Angeles, CA 90032 RACHEL RIDGWAY Department of Geological Sciences, California State University, 5151 State University Drive, Los Angeles, CA 90032 1Corresponding author email: bhibbs@calstatela.edu. Publisher: Association of Environmental & Engineering Geologists First Online: 02 Mar 2017 Online ISSN: 1558-9161 Print ISSN: 1078-7275 © 2012 Association of Environmental & Engineering Geologists Environmental & Engineering Geoscience (2012) 18 (1): 51–64. https://doi.org/10.2113/gseegeosci.18.1.51 Article history First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation BARRY J HIBBS, WYNEE HU, RACHEL RIDGWAY; Origin of Stream Flows at the Wildlands-Urban Interface, Santa Monica Mountains, California, U.S.A. Environmental & Engineering Geoscience 2012;; 18 (1): 51–64. doi: https://doi.org/10.2113/gseegeosci.18.1.51 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyEnvironmental & Engineering Geoscience Search Advanced Search Abstract The Santa Monica Mountains of southern California have undergone moderate urbanization since 1960. Just a few decades ago, many of the riverine systems in the Santa Monica Mountains were intermittent, but they are now perennial. The transition to perennial streams has led many policy makers to conclude that urban runoff from landscape watering accounts for continuous flows during the lengthy dry season. The transition to perennial flows allows expansion of habitat for exotic and harmful species, raising arguments for controls on urban runoff during the dry season. Most communities in the Santa Monica Mountains depend entirely on State Project water imported from northern California. Stable isotopes of oxygen and hydrogen show that imported water is isotopically distinct from local precipitation, providing a useful tool for tagging source flows in Santa Monica Mountain streams. In this investigation, we perform a detailed analysis of dry weather flows in one of the Santa Monica Mountain's major streams, Las Virgenes Creek. We also present results of reconnaissance surveys of several other creeks. Las Virgenes Creek accumulates most of its initial flow along an urban part of its stream reach. Chloride and sulfate scatter plots indicate that Las Virgenes Creek is dominantly fed along the urban stream reach by locally sourced, groundwater base flow. Oxygen and deuterium isotopes show that Las Virgenes Creek and other creeks in the Santa Monica Mountains contain small percentages of imported waters (less than 10 percent), indicating little urban runoff during dry weather flows. The data suggest that perennial flow in urban streams results from the removal of riparian vegetation and deepening of channels rather than from urban runoff. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.