Using the ERDC Wellbot to prevent and remediate biochemical fouling in relief wells

Abstract

Relief wells relieve subsurface hydrostatic pressures that may develop within the foundations of dams, levees, and hydraulic structures. When these wells become fouled, they can lose their ability to reduce the hydro-static pressure around the structure, which compromises its safety. Cur-rent methods for addressing fouling in relief wells can be hazardous, labor-intensive, ineffective, and expensive. This study tested the effectiveness of the US Army Engineer Research and Development Center (ERDC) Wellbot, an autonomous device that integrates UVC-emitting lamps with brushes to facilitate both physical and chemical removal of biofilm and chemical scale on the interior screen and casing of a well. The Wellbot was tested in 19 relief wells at two dams. Results were mixed, with the Wellbot generally outperforming conventional cleaning methods in qualitative visual comparison, matching conventional treatment in water level reduction, and either matching or underperforming conventional treatment in producing a specific capacity improvement. The Wellbot was simple to operate by a single person, and no training or technical expertise was required. The study identified the need for an automatic shutoff function, which, once implemented, should ready the Wellbot for wider deployment across the US Army Corps of Engineer’s more than 225 dam and levee systems.