A Study of the Safe Yield and Replenishment Conditions for the Yucaipa Basin Area, California

groundwater, Yucaipa basin, aquifers, Crafton Hills, Mill Creek

Ruiz-Elizondo, Jesús ; Unknown, Unknown

University:California Institute of Technology

Department:Geological and Planetary Sciences

关键词: groundwater, Yucaipa basin, aquifers, Crafton Hills, Mill Creek;   

Others  :  https://thesis.library.caltech.edu/10599/2/Ruiz-Elizondo_j_1954.pdf

美国|英语

来源: Caltech THESIS

【 摘 要 】

A ground water inventory made for a basin area of about51 square miles and situated 6 miles southeast from Redlands, California,disclosed that a mean annual recharge of 4322.5 acre-feet fromrainfall on foothill and mountain areas plus a mean annual deep penetrationvolume of 1693 acre-feet from water artificially applied (irrigationand domestic uses) are exceeded by local consumptive uses plus exportationlosses. Detailed studies showed that no appreciable contribution fromrainfall in irrigated and non-irrigated valley lands occurs to thesub-surface ground water body.

Elimination of the net basin drawdown loss caused byexportation will still put the overdraft within the order of 3000acre-feet per year. An inevitable increase of land cultivation bringsabout no chance to mitigate that figure in the near future.

Increasing volumes of water extraction are shown by a meanannual drop in water level of wells, from 1.67 feet for the period1927-1942 to 7.5 feet for the period 1942-1954.

An estimated specific yield of 0.1085 for the ground waterreservoir places the time-life of Yucaipa basin within 35 years,assuming the existence of a 250 feet thick aquifer under the 400 feetdeepest wells.

A depth of 650-750 feet in water wells is arbitrarilyestablished as a limit for the economic and profitable exploitationof the basin.

A conservative figure of 5000 acre-feet plus minus 1000acre-feet safe yield is based on the mean annual recharge to valleylands from foothill and mountain areas. This quantity is likely to beincreased by additional yields from the aquifer, upon rebounding and expansion.

The low porosity value and its close specific yield (0.12 and0.1085 respectively) associated with a rather low specific retentionvalue, seem to indicate that the hydrological properties of the Yucaipa aquifers reflect the existence of a type of rock near to asandy gravel, with locally abundant interstitial materials. Plio-Pleistocene(?) San Timoteo bed can well appear in Yucaipa basinat aquifer depths. Younger Quaternary fanglomerates, stream gravels,weathered soils and modern alluvium occur widely distributed in thesurface area of Yucaipa. These sediments are bordered to the north,east, and southeast by hills and mountains of basement complex rockswhich are probably pre-Cambrian, but most certainly pre-Cretaceous in age.