Water Well Journal
Issue link: http://read.dmtmag.com/i/681918
SGMA, which became effective on January 1, 2015, gives groundwater sustainability agencies local authority to develop and adopt groundwater sustainability plans intended to man- age the groundwater to maintain the "safe yield" of the basin. Basins designated as "critically" overdrafted by the De- partment of Water Resources in Bulletin 118 must have plans in place by January 31, 2020. Basins "not critically" over- drafted, but designated by the DWR as high or medium prior- ity basins must have plans in place by January 31, 2022. The Turlock Groundwater Basin Association, formed in 1995, includes members from the majority of local agencies and is providing a basis for moving forward toward SGMA compliance. They include: developing groundwater sustain- ability agencies; evaluating additional information/data needs; and developing a groundwater sustainability plan for the sub- basin. Land Subsidence The connection with recent water-level declines have been tied to land subsidence, according to the USGS and its article, "Water Availability and Subsidence in California's Central Valley." At some points, up to 11 inches of land subsidence was measured from 2012 to 2015. However, land subsidence is not new to the Central Valley. By 1970 half of the Central Valley had dropped more than a foot, according to USGS geologist Joseph Poland who led pioneering research on subsidence. The greatest subsidence tied to groundwater extraction ever recorded in the United States is on the Central Valley's west side where the water table dropped 400 feet in the early and mid-20th century. The resulting soil compaction led to a drop of more than 28 feet in an area southwest of Mendota. In the Central Valley, the USGS reports subsidence has caused costly infrastructure damage such as canal buckling and reduced freeboard on canals and bridges. For Steve, it means building a compression section with steel pipe to help prevent the well from buckling due to subsi- dence when customers elect not to go with plastic well casing. Compression sections cannot at this time be built with plastic well casing. When land subsides near a well, the subsurface soils and aquifers create substantial stress to the well casing. A com- pression section allows the well to withstand forces related to subsidence without experiencing collapsing, breaking, or being damaged to a point where it introduces sand. The com- pression section allows the casing to telescope inside of it so the pipe can move rather than crumble. Roscoe Moss Co., a manufacturer of water well casings and screens based in Los Angeles, California, says compres- sion sections are typically installed at the bottom of the blank casing (i.e., pump chamber) above the well screen. The com- pany notes a compression section cannot be retrofitted to an existing well. Therefore, the potential for subsidence must be identified during the design phase of the well. Steve will talk with the pump installer in the area he is drilling to find out at which depth wells are breaking. Depend- ing on the formation, depth of the well, and other factors, Steve might install multiple (two or three) compression sections. Compression sections are not the answer but help in fight- ing subsidence, Steve says. Harder says between 2007 and 2011 as much as 4 feet of subsidence has occurred in the Tule Subbasin west of Porter- ville. If the well does buckle, the issue of not being able to get the pump out or down the well can become a possibility. "Subsidence is mitigated by maintaining groundwater lev- els at a safe elevation," Harder says, "and groundwater sus- tainability agencies need to find out what that elevation is." A Look Ahead California's 4-year-old drought is wreaking more life- changing consequences than most realize. On the frontline of the drought in Firebaugh, 40 miles west of Fresno, struggling farmers have had to lay off workers. Struggling communities are affected when kids drop out of school to move to another area where there is work for their parents. This leads to potential layoffs of teachers due to the lack of students in school. This has occurred over the last two to three years. President Barack Obama visited Fresno and the drought- stricken town of Firebaugh in February 2014 to deliver a $183 million aid package that included money for ranchers in California who lost livestock, communities running out of water, and farmers needing help conserving their diminishing water resources. Looking ahead, California is expected to have another cycle of substandard rainfall, snowpack accumulation, and surface water delivery. The bottom line is there are more people in California than the state has water for. All eyes will be on how the Sustainable Groundwater Man- agement Act enables regulation of groundwater pumping and standards for groundwater management. Harder says the next 20 years will be interesting to see if management agencies are able to work together to devise a common solution. "If they can't find common ground, California has a his- tory of adjudication," Harder says. "Whenever attorneys get involved, it gets long and costly. I know there is motivation to avoid that." In the meantime, a heavy workload continues for Harder's small company of 10 employees. He normally works seven days a week to meet the demand. His current workload consists of three wells in Southern California and three in Bakersfield. "Water, as you can imagine, in the West is extremely con- tentious," Harder says. "It's economy and life, and when the stakes are high, it's worth fighting for, so we'll just have to see." TURLOCK AND SAN JOAQUIN from page 31 Mike Price is the senior editor of Water Well Journal. In addition to his WWJ responsibilities, Price produces NGWA's newsletter and contributes to the Association's quarterly scientific publication. He can be reached at mprice@ngwa.org. To read parts one and two of this series in the April and May issues of Water Well Journal, visit WWJ 's website at www.Water WellJournal.com. waterwelljournal.com 32 June 2016 WWJ