Taking an Innovative Approach
Carroll County navigates various challenges through dedication and efficiency
By Hanna Heiss
Addressing the needs of its citizens, providing a cost-effective solution while demonstrating innovative engineering and construction is the award winning Langdon Stormwater Management Facility project.
Carroll County began laying the groundwork for the project with the Langdon Oil Company by purchasing a five-acre parcel located at the headwaters of Double Pipe Creek in Maryland in 2014, with construction beginning April 2020 and completed March 2021. The Langdon project, a cooperative initiative with the Carroll County Bureau of Resource Management and the City of Westminster, installed a stormwater management pond adjacent to Westminster Avenue designed to remove pollutants from 96 acres of impervious area before discharging into the headwaters of Double Pipe Creek.
Beginning with an engineering analysis, it was verified that a regional wet facility could be constructed on the property. The goal of the project was to address water quality, channel protection and flood protection for the drainage area that includes over 92 acres of impervious surface. Though the Langdon property was an excellent location in terms of collecting urban stormwater runoff, site constraints such as the sloped topography and construction site access provided challenges.
Those involved in the works of the project were no strangers to challenge. Requiring over 70,000 cubic yards of overburden to be removed from the site, thus equating to roughly 7,000 dump trucks, the valley was surrounded by a residential community, accessible solely via a one lane, two-way alley. The damage to City streets and the unquantifiable impacts to the safety and convenience of residents were serious considerations that the County had to consider.
Staff determined that given the tight physical constraints of the site, typical haul-off of overburden using dump trucks was not the best option. This made a simple pond construction project a complex machine with many moving parts all reliant on each other in order to function successfully.
With the site’s close proximity to the Maryland Midland Railway, Inc. (MMD), a light at the end of the tunnel was seen. Project staff met with the MMD to discuss the potential of hauling the overburden by train to a site eight miles away in the Town of New Windsor. Having recently upgraded its wastewater treatment plant, an old wastewater lagoon was no longer needed. Conveniently located next to the railroad and in need of a fill, the New Windsor Lagoon plan fell into place.
Construction of the stormwater management facility began in April 2020 with Highland Turf, Inc. (HTI) in charge. Every morning at 7:30, MMD arrived at the site to haul away the overburden via a train consisting of ten gondolas and two locomotives and with the help of two excavators. Due to the 12-hour time limitations of the train crew, there was not always enough time to fully unload nine gondola train loads every day. As the project progressed, this issue was addressed as team members worked together to optimize operations and make necessary adjustments to maintain an as expected, normal construction pace.
Though hauling via train cost similarly to that of trucks, around half a million dollars, there were unquantified savings related to local roadway impacts and to citizens making this an extremely cost-effective option that the Bureau was able to take advantage of due to the site locations.
With the construction of the wet pond stormwater management facility beginning in April with excavation of the pond area and excess material hauling operations via MMD. Sanitary sewer relocation, on-site stream flow diversion, as well as a 20-foot-tall retaining wall and a 77-foot-long weir wall were part of the construction project. Construction was substantially complete by October 2020 and as built surveys were performed by Carroll Land Services, Inc. (CLSI). Final acceptance of the project with the completion of a perimeter fence and vegetative stabilization was achieved in March 2021.
Much funding was provided to Carroll County for the completion of the stormwater project. The Maryland Department of Natural Resources Chesapeake and Coastal Service partially funded the project with a $900,000 grant as well as the State Highway Administration Transportation Alternatives Program for funding the project with a grant for $979,941.
The total project cost, including design, property acquisition and construction came out to $3.14 million. The cost per impervious acre treated was $34,000. When considering the financial contribution of the grants, the cost to Carroll County taxpayers was just under $14,000 per impervious acre.
With their innovative approach to address site constraints in an urban location with minimal impacts to City streets and community residents the County received two awards: County Engineers Association of Maryland (CEAM) Mid-Size Project of the Year and 2022 Maryland Quality Initiative (MdQi) Under $5M Project of the Year.
The project moved through construction quickly and the impressive efficiency of the coordination between multiple contractors on multiple sites as weather, materials and a pandemic, were all constantly changing factors.
Hanna Heiss is the Assistant Editor at American Infrastructure Magazine. She can be reached at hanna@builder.media.
