31 Mar 2025

USACE Relief Wells for Dams and Levees: History and Current Practice

Abstract: The purpose of this study was to review relief well practices within the United States Army Corps of Engineers (USACE). A literature review was performed on the history and use of relief wells relief and the state of practice within the USACE. As part of this study, a survey about relief well use and maintenance practice was prepared and distributed to selected Districts containing a large number of relief wells to determine their standard operating procedures for using those wells and to learn the history of their use. Responses obtained from these Districts were tabulated and classified according to the subject categories requested. Research needs and tools were requested as part of the survey, and a large portion of the responses indicated that there is an important need for research into biofouling prevention and remediation. Finally, a laboratory experiment was performed on several commercial-off-the-shelf sensors to measure effluent flow remotely. The results of the experiment showed that remote sensing of relief well flow is viable. It was found that pore pressures could be used to measure the relief well flows over a wide range of flow rates and with an error of 10 percent or less on average. Ultrasonic sensors also performed well during testing, with an average error of 10 percent or less.

15 Oct 2024

Deployable Resilient Installation Water Purification and Treatment System (DRIPS): Relief Well Biofouling Treatment of Dams and Levees

Abstract: The US Army Corps of Engineers (USACE) conducts regular inspections and maintenance of relief wells to ensure their proper functionality and to identify early signs of malfunction or potential failure. Expenses associated with labor, materials, and transportation are the primary cost drivers of relief-well maintenance. To minimize labor hours and materials, a treatment approach intended to improve logistics and reduce material costs during relief-well treatment was developed and tested. This approach employed external UVC, mechanical brush treatments, and chlorinated-gas-infused water to produce liquid sodium hypochlorite (NaClO). Preliminary bench-scale testing with chlorine, oxalic acid, and UVC informed the selection of field testing methods and optimal amendment concentrations. Field demonstrations were conducted annually over three years. During the demonstrations, the system underwent continuous optimization to enhance its efficiency. Different locations in Mississippi (Grenada Dam, Eagle Lake, and Magna Vista) were selected for testing. Both new and traditional treatment approaches yielded adequate results, achieving microbial reduction at 96% to 100%. The development and refinement of this system demonstrated that relief wells can be treated within a comparable timeframe and with similar efficiency while utilizing fewer purchased chemicals and materials.