Arrowhead Sewer Company, Inc. hired Princeton Hydro, LLC to provide engineering services to reinstall an inflow Equalization Tank that floated due to unforeseen groundwater conditions. Given site and layout restrictions, Princeton Hydro designed groundwater and overland flow control elements to buffer the tank from groundwater uplift. The system consisted of two main parts: a diversion channel to direct the overland flow around the tank area, and a subsurface drainage system around the tank. The drainage system consisted of Invisible Structure’s Rainstore3, surrounding the tank with a curtain composed of 97 percent voids, and Draincore2 under the tank, both capturing and conveying water to a 30” outlet pipe. Princeton Hydro also designed an anchor system to fasten the EQ tank to the existing concrete pad.