17290_Authority_February_2024

6 The Authority | FEBRUARY 2024 The Dallas Area Municipal Authority (DAMA) in Luzerne County, PA acts as the stormwater authority for Dallas Township, Dallas Borough, and Kingston Township. DAMA is responsible for meeting the Pollution Reduction Plan (PRP) goals for the three municipalities, as required by the EPA and enforced by PA DEP. Given that the Authority’s jurisdictional stormwater area is so large, they had a large amount of sediment that was required to be reduced in the plan cycle. DAMA is an established wastewater and solid waste authority serving the three municipalities listed above. To accomplish the goals of the PRP, DAMA added “Stormwater” to its responsibilities and hired a full-time Stormwater Coordinator to plan and manage the PRP projects. The initial responsibility included educating the public on these requirements and how the public can help. DAMA staff worked closely with residents in order to educate them on the benefits of these improvements as well as to secure the necessary easements. Public meetings were conducted and DAMA created brochures to communicate the importance of these projects. Tom Mayka, Stormwater Coordinator, noted “I enjoyed collaborating with the local residents, township staff and ARRO to locate, plan and construct these stormwater treatment facilities”. ARRO Consulting assisted DAMA with the design, bidding, and construction of fourteen (14) stormwater facilities to help meet their PRP goals. These facilities, or stormwater Best Management Practices (BMPs), consisted of dry extended detention basins and constructed wetlands. The BMPs were designed to meet PA BMP Manual requirements, local stormwater requirements, as well as reduce discharge rates to the maximum extent possible. The main goal was water quality (sediment reduction) with a secondary goal of improving downstream flood conditions in the Toby Creek watershed. Plans and reports were submitted to the Luzerne County Conservation District for permit approval. Dry Extended Detention Basins Dry extended detention basins are common stormwater BMPs. They are designed to provide temporary storage of incoming stormwater runoff, in turn, regulating flow rates, removing sediment from the water, and reducing downstream flooding/erosion. Green Infrastructure Solutions: How DAMA Achieved Stormwater Goals By Brad Underkoffler, PE, ARRO Consulting, Inc. and Michael Schober, PE, ARRO Consulting, Inc. Dry Extended Detention Basin Example Before Unmaintained; woody vegetation on basin bottom, embankment, and structures; poor rate control; insufficient erosion and sediment control measures After Basin volume increased, modified outlet structure to improve rate control and extend detention times, rip-rap apron to protect from erosion at inflow, sediment forebay to capture and remove sediment, native seed mix installed to increase transpiration, filtration, and improve infiltration capacity of soil