Estimating Annual Precipitation in the Fenner Basin of the Eastern Mojave Desert, California

Davisson, M.L. ; Rose, T.P.

Lawrence Livermore National Laboratory

关键词: Calibration;    Data Analysis;    Geologic Surveys;    Deserts;    Droughts;   

DOI  :  10.2172/793861
RP-ID  :  UCRL-ID-139029
RP-ID  :  W-7405-Eng-48
RP-ID  :  793861

美国|英语

来源: UNT Digital Library

【 摘 要 】

Metropolitan Water District (MWD) of southern California and Cadiz Inc. investigated the feasibility of storing Colorado River water in groundwater aquifers of the eastern Mojave Desert as a future drought mitigation strategy. This culminated in the public release of the Cadiz Groundwater Storage and Dry-Year Supply program Draft EIR, which included pilot percolation studies, groundwater modeling, and precipitation/runoff analysis in the Fenner groundwater basin, which overlies the proposed storage site. The project proposes to store and withdrawal Colorado River water over a 50-year period, but will not exceed the natural replenishment rates of the groundwater basin. Several independent analyses were conducted to estimate the rates of natural groundwater replenishment to the Fenner Groundwater Basin which was included in the Draft EIR. The US Geologic Survey, Water Resources Division (WRD) officially submitted comments during public review and concluded that the natural groundwater replenishment rates calculated for the Draft EIR were too high. In the WRD review, they provided a much lower recharge calculation based on a Maxey-Eakin estimation approach. This approach estimates annual precipitation over an entire basin as a function of elevation, followed by calibration against annual recharge rates. Previous attempts to create precipitation-elevation functions in western Nevada have been difficult and result in large uncertainty. In the WRD data analysis, the effect of geographic scale on the precipitation-elevation function was overlooked. This contributed to an erroneous Maxey-Eakin recharge estimate.