Evaluation of the potential groundwater resources of the Golem well West Rancho Bernardo, San Diego County, California.

摘要

The Golem well is tapping a confined aquifer which terminates into volcanic bedrock. The well has been flowing under artesian conditions since it was installed in September 1951. The Olivenhain Municipal Water District (OMWD) has expressed an interest in determining whether the well has the potential to produce sufficient water resources to provide irrigation water for secondary use. In order for the artesian well to be of beneficial use to the OMWD, it would require approximately 2,000 acre-feet per year.; The geologic mapping indicates that an interconnected fracture pattern exists in the bedrock. These fractures facilitate the upper mountain front recharge into the deep interconnected fractures of the metavolcanic bedrock deep within the confined aquifer. The video surveillance of the Golem well showed that the fractured bedrock produced water at depth. A geophysical survey of the well was conducted and indicated that the confined layer above the fracture zone did not consist of clay material. Aquifer tests show that the transmissivity values ranged from 800 gpd/ft to 24,500 gpd/ft. Hydraulic conductivity values ranged from 3 ft/day to 72 ft/day. Based on the aquifer test data, the sustainable well yield is anticipated to be between 75 to 80 gpm. A groundwater flow model was developed for the study area to delineate the capture zone for the aquifer system using time-of-travel which indicated that the trend is towards the northeast, in the upgradient direction, towards the valley's higher elevations. Based on the above, the artesian well does not appear to produce the sufficient quantity of water for irrigation use.