Prior to this restoration project at George Cromwell Elementary School, two of three outfalls draining into the site were found to be more than 50% full of sediment. So, the overall objective of this project was to design a natural drainage system for stormwater treatment while also providing adequate drainage and safe conveyance of storm flows that would protect the school property and adjacent public roadways.
This project also contributed to the county’s waste load allocation toward the Chesapeake Bay Total Maximum Daily Load by maximizing the water quality credit potential of the site. Prior to the project, the annual pollutant load entering the site was estimated to be 117 pounds/year of Total Nitrogen (TN), 7 pounds/year of Total Phosphorus (TP), and 1.8 tons/year of Total Suspended Sediments (TSS). Proposed water quality treatment load reductions achieved by the project for TN, TP, & TSS are 74%, 76%, and 97% respectively .
Along with its stormwater purposes, the project brought an educational component with it given its location. An outdoor classroom space was created adjacent to the school which will be used to expose students to the water cycle, the preservation of Chesapeake Bay and the importance of protecting natural waterways.
“Not only will the site offer long-term treatment and storage of nutrients and sediment, but the educational benefit offers arguably even more value as a tool to empower future generations of property owners, designers, builders, and government officials to also be stewards of the Chesapeake Bay,” Jeff Ratteree, project manager with the Bureau of Watershed Protection & Restoration project, said.
One year after construction, the project is stable and performing as intended. The native marsh plantings have all taken root and the project site is able to drain the most frequent rain events within 72 hours.
Location: Glen Burnie, Maryland
Cost: $770,000
Size: DA 9.99 acres w/3.77 acres of Impervious; Limit of Disturbance = 1.33 acres
Owner: Anne Arundel County Board of Education
Manager: Jeff Ratteree
Designer: Ashton Rogers
Contractors: Designed by Ashton Rogers of GHD, Inc., Constructed by Underwood & Associates, Construction Management & Inspection by Gannett Fleming
Manufacturers: Komatsu, Doosan, Gehl & Morooka
