The assessment concludes: “Groundwater pumping is known to be a leading cause of subsidence in the San Joaquin Valley … the groundwater to be conveyed under the Proposed Action is within the range of historical pumping by the district, and would be pumped regardless of whether Reclamation allowed its conveyance in federal facilities.” Unfortunately, this excessive water extraction from the unconsolidated deposits of the San Joaquin Valley causes land subsidence. In areas where surface water replaced withdrawal of ground-water, water levels in the confined system rose sharply and subsidence slowed. Beginning around the 1920's farmers relied upon groundwater for water supply. Get this from a library! 2). Subsidence detection and mapping programs are critical to the scientific understanding and management of our land and water resources. Because the valley is semi-arid farmers rely heavily on surface-water diversions to meet irrigation water demand, but the recent droughts have induced substantial increases in groundwater pumping. Plus a brief update on the voluntary agreements, and good news on the Colorado River. Department of … Subsidence Monitoring Reclamation surveys a network of over 70 control points across the San Joaquin Valley in July and December of each year to monitor ongoing subsidence. Over time, overpumping caused groundwater-level declines and associated aquifer-system compaction and land subsidence that resulted in permanent aquifer-system storage loss. Following are the bi-annual survey result tables, maps, and ArcGIS shapefiles. [J F Poland; B E Lofgren; R L Ireland; R G Pugh; Geological Survey (U.S.); California. Land Subsidence in the San Joaquin Valley September 6, 2017 News By Laura Ramos The California Department of Water Resources and the Water Education Foundation highlighted an array of technologies available for subsidence measurement and monitoring, including information and technical support being provided by DWR. Total subsidence and costs are expected to be much greater today, but little data are available to quantify total damages. Land Subsidence from Groundwater Use in California Report of Findings, 2014. Land subsidence can damage critical infrastructure, including water delivery systems, levees, roads, and bridges. The San Joaquin Valley is one of the most productive agricultural regions in the nation. Over time, subsidence can permanently reduce the underground aquifer's water storage capacity. Recently, the Department of Water Resources released a report to supplement the 2017 California Aqueduct Subsidence Study (CASS) report that addresses the specific issues within a 10-mile-wide study corridor centered on the California Aqueduct south of San Luis Reservoir to the southern San Joaquin Valley … Almost 4 feet of subsidence occurred in some San Joaquin Valley areas over the past decade with current subsidence at a rate of one inch per month in the most severe cases. In 2017, DWR worked with NASA to release a report on San Joaquin Valley subsidence citing areas along the California Aqueduct that have experienced almost two feet of subsidence over three years. Increased reliance on aquifers during the last decade resulted in subsidence rates in excess of a foot per year in some parts of the region. San Joaquin Valley continues to sink because of groundwater pumping, NASA says Subsidence occurs when water is removed from underground aquifers and the surrounding soil collapses on itself. Land subsidence can damage critical infrastructure, including water delivery systems, levees, roads, and bridges. Over time, subsidence can permanently reduce the underground aquifer's water storage capacity.

Damages resulting from land subsidence in Santa Clara Valley are estimated at more than $756 million. Which of the following statements describes subsidence at the central (San Joaquin) valley of California? Because the valley is semi-arid farmers rely heavily on surface-water diversions to meet irrigation water demand, but the recent droughts have induced substantial increases in groundwater pumping. A.Gradual subsidence occurred over several decades due to the deep subsurface withdrawal of oil and gas. B.Gradual subsidence occurred over several decades due to the withdrawal of groundwater mainly for irrigation purposes.

Long-term subsidence has already destroyed thousands of public and private groundwater well casings in the San Joaquin Valley. Subsidence.