Mill Hill Water Main Extension
Mill Hill Road is a two-lane road in Bennsville, Maryland that is section by section transitioning from narrow lanes, with little to no shoulder to two full-width lanes, with wide shoulders and turn lanes along with improved drainage. The next section of road improvements is from Davis Road past Super Street to Devonfield Avenue, which was designed by GMB, as the Mill Hill Road Improvements project (VCI No. 05-0085).
Prior to the road improvements going to construction, the County’s Department of Planning and Growth Management realized that extending water main through the portion of Mill Hill Road from Super Street to Devonfield Avenue to connect to existing water main on each end to interconnect existing water main in the Southerland Subdivision and the Avalon Subdivision would result in several benefits including creating another loop in the system which enhances flow & pressure and system reliability, providing better fire protection coverage, serving additional residential units, and preparing for additional anticipated future development further south on Mill Hill Road.
The result was the Mill Hill Road Water Main Extension project (PGM No. DSP-210037) which is comprised of 1,282 LF of 12-inch, 79 LF of 8-inch, and 70 LF of 6-inch ductile iron water main tying into existing 12-inch water main in Mill Hill Road at Super Street, existing 8-inch water main in Super Street, and existing 8-inch water main in Devonfield Avenue with a stub for extending the 12-inch water main further south on Mill Hill Road in the future.
Complicating design of the water main was the fact that construction of the road improvements was slated to take place prior to construction of the water main. Therefore, GMB developed a design that would affect the road improvements as little as possible, although it did require additional plans and specifications to supplement the Mill Hill Road Improvements project in order to relocate an existing fire hydrant that was in an area where the roadway would be widened plus to install two steel casings / sleeves for the proposed 12-inch main to cross Mill Hill Road and Devonfield Avenue and two HDPE casings / sleeves for Water House Connections (WHCs) crossing Mill Hill Road in order to prevent having to excavate through what will be a newly reconstructed roadway at the time of their construction.
In addition to the water main and casings / sleeves, the design of the water main extension also included maintenance of traffic, erosion & sediment control, and site restoration including some pavement repair in Devonfield Avenue at the tie-in to the existing water main.