Culvert Replacements and Drainage Retention Area Design
The City of Beverly was experiencing flooding during large storm events along Chubbs Brook. BETA was hired by the City to design two culvert replacements and a stormwater detention area.
The two existing culverts were under a state-owned road and the MBTA’s commuter rail tracks. The new culverts were planned to provide additional drainage capacity at these two crossings, and would be 6’ x 4’ and 8’ x 4’.
The City has implemented stormwater retention areas along the Chubbs Brook through other projects. BETA was tasked with designing an additional retention area. The design features two walls at the required elevation with drainage pipes running through the walls. Under normal conditions, water drains normally through the drainage pipes, but when a large storm is expected, the pipes can be valved off, allowing the retention of stormwater to be held back until such time as the Chubbs Brook has sufficiently drained to release the stormwater back into the brook.
The projects have a major permitting component. For the MBTA culvert, the work is to be done abutting a salt marsh. As a result, careful consideration for this protected area needed to be taken. The new culvert needed to be in the footprint of the existing culvert for permitting purposes.
For the stormwater retention area, the work would take place abutting a wetland, and would use this wetland as a natural drainage area. Coordination with the local Conservation Commission, as well as with MassDEP was required.