The Dredging Feasibility Study is an engineering study to address the feasibility of dredging sediment that has accumulated within the Reservoir since it was placed into operation over 40 years ago. The study incorporates several recommendations made by a citizen task force in January 2009, as well as comments from citizens and elected officials, and contains various types of information, to include a bathymetric survey to determine current contours of the reservoir, sampling of the sediments to determine physical and chemical characteristics, and an evaluation of impediments within the accumulated sediment profile that may limit the ability to remove sediment. The study also addresses what to do with sediments removed from the Reservoir, including what processing is required, where to carry out processing, and where to store or dispose of the material. It is anticipated that the volume of sediment could be as high as one million cubic yards or greater (a cube three feet high, three feet wide, and three feet deep is one cubic yard), so the questions of processing and disposal after dredging can become complex.
The completed study provides an estimated volume of sediment that can be removed and an estimate of the cost of such removal, including the further processing that would be required after dredging.
A Request for Proposals was issued by the Authority in May 2009 and eight engineering firms submitted proposals. In August, 2009 the Selection Committee unanimously selected HDR, an engineering firm with significant experience in dredging projects. In October, 2009 the RWSA Board of Directors authorized a contract with HDR to carry out a study which included a bathymetric survey and volume analysis, an assessment of wetlands within the reservoir, characterization of the sediments, evaluation of alternative methods of dredging and of alternatives for dewatering/processing the dredged sediments.
The completed study was presented in two parts and can be viewed by clicking on the "Work Progress Reports" tab on the left side of this page.
