February 24, 2015
Dannon Garth Pond was originally a legacy farm pond that was modified to a stormwater pond during the development of the surrounding area in the 1980’s. The Columbia Association received an emergency repair order to address the severely corroded CMP barrel that over time had deteriorated beyond repair, and awarded the design contract to SMC.
The renovation design provides a stable outfall and brings the pond into compliance with current MD-378 Standards/Specifications. A weir wall and step pool spillway convey flows, including the 100-year discharge, from the weir wall to the receiving stream. This approach reconnects the pond to the downstream riparian habitat.
The design alternatives analysis determined that the permanent pool stage would need to be lowered to meet current MD-378 standards while not increasing discharges. The lowering of the permanent pool resulted in the need to provide grade control structures in each tributary to prevent head cutting, and dredging to maintain depths and water surface area. SMC also prepared a wetland bench planting plan for the proposed hydrologic conditions and to enhance habitat and aesthetic value.
SMC secured all required permits from MDE, USACE, and Howard County in an efficient manner through pre-application meetings, and use of the County’s Red Line Review process. SMC also secured a waiver for the in-stream construction closure period to keep the project on schedule.
The work included complete design, permitting, construction oversight, compaction and materials testing, and as-built certification.