In the summer of 1994, USEPA responded to an oil release into the Housatonic River emanating from 140 Roosevelt Drive, the former Hull Dye facility, in Derby, Connecticut. This facility houses two electricity producing turbines which, when operating, were powered by water from an up-gradient canal which is fed by the Housatonic River. Oil saturated soil and river sediment were excavated and an interceptor trench and recovery well system installed. In 1999, another oil sheen appeared which was emanating from the facility tailrace. At that time, US EPA and the State of Connecticut requested that the turbines be shut off as it was believed that the vibration and water movement was exacerbating the flow of oil into the race. A second oil recovery system was designed (Derby-2) and installed over the source area in August 2000 and was operated up until 2013.
For additional information, visit the
, Pollution/Situation Report
Due to a continuing seepage of subsurface oil into the facility tailrace, a sandbag and riprap dam that physically separates the tailrace from the Housatonic River was constructed during February and March of 2007.
In May, 2017, the tailrace was drained and examined to determine if it was feasible to seal the floor and walls which would be needed to bring the plant back on-line. The condition of the tailrace was worse than expected, with cracks, fissures and additional seeps of oil that had not been previously identified. EPA determined that sealing the walls and floor as planned was not feasible.
In late August, 2017, a geophysical survey was conducted to both determine the thickness of the tailrace floor and to map the surrounding bedrock. This work was meant to assist in evaluating the viability of reconfiguring the tailrace/discharge tubes that would allow for potential re-use of the hydro-plant.
After discussing the situation with National Pollution Funds Center (NPFC) Case Officer, it was determined that EPA would evaluate two options. The first was to bring the plant back on line as a viable hydroelectric plant and the second was to effectively shut down the facility. The deciding factors would be the ultimate cost and the probability of preventing future discharges of oil to the river.
In March, 2018, EPA issued a task order to EPA contractor, Nobis Group, to prepare 30% design/cost estimates for two potential remedies (Courses of Action (COAs)) selected for the Roosevelt Drive Removal Action. The first COA was to do what is necessary to the existing hydro-power system that will allow it to run and produce energy while not allowing any free product (oil) from reaching the river. The second COA is to seal or encase the tailrace to prevent any leaching of oil to the river which would render the existing plant unusable.
The report concluded COA-1 (bring the plant back on-line) is more expensive ($7.6M) than COA-2 (sealing the tailrace) ($3.8M) and will take longer to implement, but it will allow the hydropower station to come back online and will be more protective of the environment. The NPFC and EPA, upon reviewing the report, agree that attempting to bring the plant back on line is cost prohibitive. In addition, EPA will ensure that an oil recovery system is built into the permanent closure design, so the potential for a future oil breakout to the river is diminished.
In late June, 2019, EPA tasked Nobis Group to prepare a 100% design/cost report for sealing the tailrace and permanent closure of the hydro-plant, building on the 30% design/cost. Since that time, Nobis and their subcontractors have been acquiring additional data via field investigations, and sampling and analysis. Activities have included: a general ground survey; verification of the estimated bedrock profile in the tailrace and river transition areas; confirmation of the depth along the proposed sheet pile wall; and groundwater, surface soil, soil boring/permeability and, surface water and sediment sampling. The 100% design/cost report is scheduled to be completed by late January, 2020.
Once the report has been accepted by EPA, construction work is expected to begin by early summer 2020, pending the availability of funds. McCallum Enterprises 1 Limited Partnership (MELP) is currently looking to sell some of the power generating equipment, including the turbines, prior to the shutdown.