The consulting firm for this project shall provide all the requisite professional engineering services necessary for the demolition and total replacement of Bridge MN-4 on County Route 527 (Smithburg Road) over Manalapan Brook. Additionally, said construction documents will also include the rehabilitation of the Manalapan Brook Pond Dam (NJDEP Dam File No. 28- 032) in accordance with the NJDEP Bureau of Dam Safety requirements. Bridge MN-4 is a single simply supported span consisting of a reinforced concrete slab and a 2” minimum bituminous overlay riding surface supported on timber abutments. The bridge has an overall length of approximately 13 feet. The cross section consists of two 12 foot travel lanes and 1 foot shoulders in each direction for a curb-to-curb width of approximately 27 feet. The out-toout width of the bridge is approximately 37.5 feet. The bridge is offset from centerline to the east (downstream). The bridge has an estimated Average Daily Traffic (ADT) of 10,500 and a posted speed limit of 45 mph. Manalapan Brook Pond Dam is an earth fill embankment approximately 170 feet long and 9 feet high with timber bulkheads installed along the upstream and downstream side of the roadway/embankment crest. The primary spillway structure consists of a timber box-inlet drop spillway which is located directly upstream of Bridge MN-4 with an effective weir length of approximately 54 feet. Manalapan Brook Pond Dam is classified as a Class II, Significant Hazard Dam and is in Poor Condition. Based on a previous hydrologic and hydraulic study, the existing spillway structure has an inadequate spillway capacity and cannot safely pass the recommended storm design flood. Manalapan Brook Pond Dam is owned and maintained by Monmouth County Park System. The Manalapan Brook Pond Dam impounds the waters of Manalapan Brook to create Manalapan Brook Pond, also known as Bulks Lake. This pond serves as a water supply for an irrigation system for the Monmouth County Park System’s Charleston Springs Golf Course. The Design Engineer shall coordinate the design to ensure the irrigation water supply and system remains operational after the rehabilitation of the dam.
