&EPA Office of United States Ground Water and Environmental Protection Agency Drinking Water CLASS V UIC STUDY FACT SHEET SALT WATER INTRUSION BARRIER WELLS What is a salt water intrusion Salt water intrusion barrier wells are Class V underground injection control (UIC) barrier well? wells used to inject water into a fresh water aquifer to prevent the intrusion of salt water. These wells may have secondary purposes, such as to recharge an aquifer with fresh water to be used later or to control land subsidence (reduce ground movement). What types of fluids are injected Waters of varying qualities are injected to create salt water intrusion barriers. into salt water intrusion barrier including untreated surface water, treated drinking water, and mixtures of treated wells? municipal wastewater and ground or surface water. Do injectate constituents exceed Available data show that the injectate typically meets primary and secondary drinking drinking water standards at the water standards and health advisory levels at the point of injection. point of injection? What are the characteristics of the Salt water intrusion barrier wells are drilled to various depths depending on the depth injection zone of salt water intrusion of the aquifer being protected. They inject into fresh ground water aquifers used as barrier wells? drinking water supplies that are in hydraulic connection with an extensive salt water body, such as a sea, a salt lake, or an ocean. Are there any contamination No contamination incidents associated with the operation of salt water intrusion incidents associated with salt water barrier wells have been reported. intrusion barrier wells? Are salt water intrusion barrier Because protection of drinking water supplies is the major goal of a salt water wells vulnerable to spills or illicit intrusion barrier well and the injectate typically meets drinking water standards, salt discharges? water intrusion barrier wells are unlikely to receive spills or illicit discharges of potentially harmful substances. How many salt water intrusion There are 315 salt water intrusion barrier wells documented in the United States. The barrier wells exist in the United number of salt water intrusion barrier wells in the nation is estimated to be greater States? than 609, but unlikely to be higher than 700. Where are salt water intrusion All documented salt water intrusion barrier wells are located in CA (308), FL (1), and barrier wells located within the WA (6). In addition, as many as 200 salt water intrusion barrier wells are believed to United States? exist in NY. There also may be some wells in NJ; however, the exact number of such wells in this state is unknown. How are salt water intrusion barrier Permit bv rule: CA wells regulated in states with the largest number of this type of well? Individual permit. FL, NY, and WA Where can I obtain additional For general information, contact the Safe Drinking Water Hotline, toll-free 800-426- information on salt water intrusion 4791. The Safe Drinking Water Hotline is open Monday through Friday, excluding barrier wells? federal holidays, from 9:00 a.m. to 5:30 p.m. Eastern Standard Time. For technical inquiries, contact Amber Moreen, Underground Injection Control Program Office of Ground Water and Drinking Water (mail code 4606), EPA, 401 M Street, SW, Washington, D.C., 20460. Phone: 202-260-4891. E-mail: moreen.amber@epa.gov. The complete Class VUIC Study (EPA/816-R-99-014, September 1999), which includes a volume addressing salt water intrusion barrier wells (Volume 20), can be found at http://www.epa.gov/OGWDW/uic/cl5study.html. ------- |