Step-Pool Stormwater Ribbon Cutting

Cecil County, MD

A ribbon cutting ceremony was held on June 4, 2013 to celebrate the completion of the Step-Pool Stormwater Conveyance (SPSC) Project at the Central Landfill in Cecil County, MD. The Step-Pool Stormwater Conveyance Channel was substantially completed in December 2012, and final work on aquatic plantings was recently completed.

Cecil County Public Works retained WHM Solutions, Inc. to design, permit, and construct a SPSC using regenerative stormwater conveyance/coastal plain outfall design techniques. WHM assembled a team to assist in the design, permitting and implementation phases of the project that included; BAI Group Inc. who contributed the permitting and construction monitoring of the regenerative step-pool system; and Aquatic Resource Restoration Company which was the contractor for the construction of the SPSC system.

The purpose of the project was to demonstrate the effectiveness of SPSC to reduce turbidity of problem clay soils that generate colloidal sediments that are generated from the routine operation of the Central Landfill. Initial data is supporting that the SPSC is capable of passively removing suspended colloidal clay from stormwater and promoting infiltration of water into the subsoils. The SPSC is comprised of numerous step pools planted with hydrophytic vegetation that provides retention, a filtration, and infiltration process that decrease stormwater runoff and turbidity. The outcome is improved water quality to the receiving stream that confluences into the Chesapeake Bay, which is located within four miles of the project.

This innovative approach has been successfully demonstrated as a post construction stormwater facility. However, this project is the first of its kind to use SPSC to treat stormwater from construction activities. It is expected that water quality from the SPSC will continue to improve over time as the site vegetation matures. The long term water quality benefits associated with the SPSC are being studied for the project and will be reported to the Maryland Department of the Environment.

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