The Watershed Approach to Toxics Assessment and Restoration (WATAR) finds success through collaborative efforts between state, federal, non-governmental organizations, and volunteers to leverage resources and increase project efficiency. By utilizing cutting-edge scientific technology and methods, the data collected by WATAR is able to inform decision-making and policy changes which govern human health and the environment.
Mirror Lake- Dover
For the past several decades, the ecosystem health at Mirror Lake in Dover had been in decline due to chemical contamination from previous industrial activity in the area. These contaminants accumulated in the sediments, aquatic life, and plants. Due to safety concerns, a fish advisory has been in place since 1988. In 2013, a community-wide effort brought together DNREC and collaborators from University of Maryland-Baltimore County, City of Dover - Silver Lake Commission, Brightfields, Inc., Biohabitats, Inc., Delaware's Boot Camp Program, AmeriCorps volunteers, residents of a local shelter, and local political leaders to complete a remediation and restoration project at Mirror Lake using an activated carbon product and the creation of intertidal wetlands.
Activated carbon is the same technology used in many water filters for drinking water or fish tanks. This project marks the largest application of this activated carbon product, SediMite™, anywhere in the United States and is the first state-funded sediment remediation project of its kind in the country. The wide use of volunteers whenever possible is estimated to have saved between $100,000 and $150,000 in project expenses. A portion of the budget was dedicated to planting nearly 430 shrubs and more than 2,000 native plants suitable for wetland conditions. The plantings help restore the ecology of the lake and create habitat for fish.
DNREC monitored the conditions of Mirror Lake after the treatment and restoration project to determine the effectiveness of the innovative method by collecting and analyzing sediment, water, and fish tissue samples. In 2014, after the first year, scientists already saw a 60% reduction in total polychlorinated biphenyl (PCB) concentrations in resident fish. In 2016, after 3 years, there had been an 87% reduction in total PCB concentrations in resident fish. Overall reductions in PCB concentrations are slightly less than expected; however, the system recovery has been accelerated by approximately 20 years as compared to equivalent models of Monitored Natural Recovery. The fish advisory for the St. Jones River, including Mirror Lake, has become less restrictive than before the project occurred, increasing the recommended maximum amount of fish consumption from two meals to four meals per year. DNREC will continue to monitor this stretch of river in the future to track further changes and hopefully improvements.
Little Mill Creek and Meco Ditch - New Castle County
The focus on Little Mill Creek began with a flood mitigation project. Collaborative work also led to the remediation of a nearby contaminated site at Meco Drive.
For over 60 years, extensive flood damage had been attributed to development along the floodplain on Meco, Germay, and Brookside Drives - all historically built on filled wetlands. During heavy rains, the runoff from paved areas flowed into Little Mill Creek, which could not accommodate the extra water and led to flooding on its banks and in upland areas. To address this problem, the first phase of the project aimed to protect private residents in the area by widening and deepening the channel.
The second phase focused on protecting more than 40 businesses and commercial properties along Little Mill Creek. In addition to widening and deepening the channel, it was also fitted with riprap and erosion control matting. Then a vegetative cover was planted to stabilize the creek banks, slow floodwaters, and improve the natural ecosystem. The Army Corps of Engineers, New Castle Conservation District, and multiple divisions within DNREC partnered together to complete this project.
This construction project was also carefully coordinated with clean-up activities at the nearby contaminated Meco Drive site to address a serious water quality problem. Oil containing harmful pollutants was seeping into the stormwater ditch, which then discharged into Little Mill Creek, resulting in contamination of the creek. It was determined that this was the source of an on-going release that was impacting multiple waterways in the area, including the Russell W. Peterson Urban Wildlife Refuge. The Meco Drive site was also identified as one of the sources of contamination calling for a fish consumption advisory on the Christina River. To address this problem, the area of contaminated sediment was excavated and properly disposed of and replaced with an activated carbon/bentonite barrier to prevent any residual migration of contaminants. Additionally, 6,500 lbs. of activated carbon was applied to the banks of the waterway to remediate residual contaminants in the creek. Watch the Meco Ditch Remediation video for more information.
Page reviewed 3/6/19