Seepage Control Remediation at Hodges Village Dam, Oxford, Massachusetts

This paper presents a case study on embankment dam seepage problems encountered at one site over the last 30 years and various remediation efforts. The Hodges Village Dam in Oxford, Mass. is part of an extensive flood control network built and operated by the U.S. Army Corps of Engineers in the Thames River basin of Massachusetts and Connecticut. The dam consists of a relatively homogeneous and pervious sand and gravel embankment on stratified glacial outwash sands, gravels, and cobbles. Because it was designed primarily as a run-of-the-river, flood control facility with no anticipated long-term pool storage, no significant seepage control measures were ever constructed for the dam. This paper describes a series of seepage events that have occurred at the dam starting in 1968 and continuing to 1993. Remediation efforts after each of the events are described as are their effects on dam performance. The paper concludes that the past seepage problems at the dam were caused by assumptions made about foundation soil conditions prior to dam construction, problematic drains and relief wells that resulted in significant head buildups in their respective zones of influence, and insufficient subsurface information prior to design and construction. Investigation and analyses of the dam conducted after the 1993 event are presented, and plans are described for a seepage control remediation project currently under construction.