Teller Dam is located on the Turkey Creek River south of Colorado Springs, Colorado. The purpose of the project is to mitigate potential seepage pathways that could contribute to internal erosion of the dam and abutment rock-interface. The cut-off wall consists of two components, approximately 70 to 115-foot long secant piles through the left end of the dam, abutment contact and into the left abutment, and a connected grout wall to further extend the interception of seepage pathways. H2R provided key quality control services to Bauer Foundation Corp. of both the 12,500 ft2 cut–off secant pile wall and 19,000 ft2 of grout curtain. H2R provided specialty coring services of both elements, in-situ permeability tests, and borehole inclination testing.