One of the alternate plans for water utilization being considered by the California Department of Water Resources in the Chino-Riverside and Bunker Hill-Yucaipa areas in southern California involves partial mining of ground water during the period 1965-2015, and consequent substantial lowering of water levels. The Department wants to know whether land subsidence would be a problem as a result of the postulated lowering. To answer this question, to the extent that leveling control permits, the present study has been made at the request of and in cooperation with the State of California.
At a few locations in the Chino-Riverside and Bunker Hill-Yucaipa areas, comparable water-level decline and subsidence data are available from which rough estimates can be made of subsidence that would occur as a result of the postulated lowering from 1965 to 2015. Limited leveling control, and apparent discrepancies in the data, preclude accurate determination of amounts of subsidence caused by historic water-level decline.
Based on 1965-2015 water-level changes postulated by the California Department of Water Resources and on available subsidence/head decline ratios, as much as 6 feet of subsidence might occur northeast of the San Jacinto fault between Loma Linda and San Bernardino, in an area of more than 350 feet of projected water-level decline. Also, as much as 1.5 feet of subsidence might occur in the vicinity of Ontario.
|Title||Estimated subsidence in the Chino-Riverside and Bunker Hill-Yucaipa areas in Southern California for a postulated water-level lowering, 1965-2015|
|Authors||Ben Elder Lofgren|
|Publication Subtype||USGS Numbered Series|
|Series Title||Open-File Report|
|Record Source||USGS Publications Warehouse|