HR: 0800h
AN: H11C-0671    [Abstracts]
TI: Examining Sources of Water in Springs, Wetlands, and Oases in Coachella Valley
AU: * Aguirre-Robertson, R
EM: rrooxxyy@gmail.com
AF: California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA 90032,
AU: Hibbs, B
EM: bhibbs@calstatela.edu
AF: California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA 90032,
AU: Kelliher, M
EM: mkelliher@wrd.org
AF: California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA 90032,
AU: Andrus, R
EM: rellenan@yahoo.com
AF: California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA 90032,
AB: The All American and Coachella Canals were constructed in the 1930's to supply irrigation to the Imperial and Coachella Valleys. The diverted Colorado River water is the only source of water in the valleys, and an extensive series of wetlands have been created by leakage from the unlined portions of these canals. Although the wetlands were natural features prior to canal construction, their extent was limited due to minimal recharge. As of December of 2006 these canals have been completely lined which is predicted to decrease the flow to the wetlands and may affect the flora and fauna they have come to support. Samples were collected prior to the lining of the canal from June to October 2006 from several springs and well locations downgradient from Coachella canal to assess their geochemical and isotopic signatures for comparison to canal and native groundwater sources. Analysis of stable isotopes identified three distinct groups of water: one group consisting of nearly pure Canal water with delta 18O ranging from -11.3 to -11.7 per mille and delta 2H ranging from -84 to - 95 per mille, a second group consisting of nearly pure native groundwater with delta 18O ranging from -7.3 to -8.7 per mille and delta 2H ranging from -59.5 to -71 per mille, and a third group consisting of various mixtures of Canal and native groundwater with delta 18O ranging from -8.7 to -11.1 per mille and delta 2H ranging from -80 to -91 per mille. Minimal isotopic change has occurred in a sampling campaign conducted June, 2007. Continued monitoring of the isotopic and hydrochemical signature of the waters will reveal how quickly they might evolve toward that of native groundwater as a direct result of decreased recharge from the now lined Coachella Canal.
DE: 1803 Anthropogenic effects (4802, 4902)
DE: 1830 Groundwater/surface water interaction
DE: 1872 Time series analysis (3270, 4277, 4475)
DE: 1890 Wetlands (0497)
SC: Hydrology [H]
MN: 2007 Fall Meeting