Water Well Journal
Issue link: https://read.dmtmag.com/i/557876
sand, gravel, limestone, dolomite, sandstone, basalt, glacial moraines, and fractured hard-rock aquifers. About a quarter of the storage aquifers are brackish, with salinities up to 20,000 mg/L total dissolved solids. All of the remainder store water in fresh aquifers, but in almost all cases these contain one or more constituents in the native ground- water that are not wanted in the water recovered from storage, such as iron, manganese, fluoride, hydrogen sulfide, arsenic, chromium, nitrate, etc. For most of these constituents in the native groundwater, appropriate ASR operations can be implemented to control concentrations in the recovered water to acceptable levels. Some ASR sites may require pre-treatment or post-treatment in order to meet water quality goals. Water sources for ASR storage are primarily drinking water; however, other sources include highly-treated re- claimed water, filtered surface water, and also groundwater from either a different aquifer or from the same aquifer at a different location where water quality is good. Water Well Journal: From a driller's and pump installer's perspective, is there specialty training needed to drill, install, and maintain ASR systems? Scott: Dual purpose wells (built for injection and withdrawal) are specialized and require special expertise in both their design and construction. Pyne: ASR is not rocket science, but there are several impor- tant differences in the design, permitting, construction, and operation of ASR wells and wellhead facilities, compared to conventional production or injection wells. Understanding these differences is essential to achieving ASR success. Some ASR well failures have not really been due to failure of ASR technology, but have been instead due to inappropriate design, regulatory constraints, well construction, well equip- ping, initial cycle testing, or subsequent operations. Basic principles have been developed, based upon experi- ence with ASR science and technology development during the past 35-plus years. This information is readily available through books and other publications, conferences, webinars, etc. from reputable sources such as the National Ground Water Association and the American Ground Water Trust. There is also misinformation about ASR that is on the Internet, so it is important to seek reliable information sources that have proven ASR experience. Water Well Journal: Do you think there will be more ASR projects installed in the future? Scott: Yes, I expect ASR projects and other types of recharge to play an important role in developing future water supplies. Pyne: Several important global issues suggest ASR has a bright future. These include meeting projected increasing water needs with high reliability; long-term climate change and associated increased frequencies of droughts and floods; sea level rise in populated coastal areas; continued declines in groundwater levels in many parts of the world; and the need for environmental protection. It is clear storing more good quality water when we have it available will be needed. Storing water aboveground in new surface reservoirs will likely continue, despite adverse envi- ronmental effects, high costs, water losses to evapotranspira- tion, and loss of valuable land that could have been utilized to meet other pressing needs. Construction of ever-longer pipelines to tap increasingly distant new water sources will continue. As the saying goes, "Water flows uphill to money." Supplementing water supplies with brackish water and seawater desalination, and importing high quality drinking water by VLCC tankers, will increas- ingly be implemented. High level treatment and reuse of wastewater will also be implemented far more widely. All of these options are expensive. For most areas, storing water underground in ASR wells is a proven, viable water management option far less expensive and achieves water supply reliability. Combining ASR wells with these other water supply options makes sense, increasing the yield and reducing unit costs for supplemental water supplies. This ASR well is part of the Hilton Head Public Service District in South Carolina. Lana Straub, with a background in the legal and financial aspects of small business, is the office manager of Straub Corp., Stanton, Texas, an environmental and water well drilling firm owned and operated by her family for more than 50 years. She can be reached at Lana @StraubCorporation.com. WWJ WWJ September 2015 29 Twitter @WaterWellJournl Learn ASR at the Expo Peter Scott will be delivering a workshop on aquifer storage and recovery at the Groundwater Expo. The session is titled "Aquifer Storage and Recovery" and takes place from 1:45-2:45 p.m. on Tuesday, December 15. Here is more information on it: Water supplies are approaching critical levels in many western areas with declining reservoirs and groundwater levels. Additional storage, particularly surface storage, can be difficult to achieve. Aquifer Storage and Recovery (ASR) has been used successfully to increase available water supplies in some areas. This workshop will present an overview of the factors involved in successful ASR development using several western case studies.