Malaga Lake Dam, located on U.S. Route 40 across Scotland Run in Franklin Township, Gloucester County, NJ, is more than 100 years old. Although the dam was generally well maintained, normal deterioration and updated design criteria resulted in the need for major rehabilitation. The prime deficiency was that the spillway did not have sufficient capacity to safely pass the current and more stringent design flood. The dam owner, NJDOT, recognized that until the dam was upgraded, the possibility of failure posed a significant threat to the residents and businesses located downstream, the continued use of the lake and the operation of Route 40.
The Approach
McCormick Taylor completed an inspection, evaluation, design and construction program for the rehabilitation of Malaga Lake Dam, a high-hazard dam formed by the roadway embankment for U.S. Route 40. The program included preparation of an inspection report and detailed evaluations. The evaluations included subsurface investigations, hydrologic and hydraulic (H&H) analyses, geotechnical evaluations, and incremental dam break analysis. Rehabilitation alternatives were developed and evaluated. Final design of the selected alternative included preparing contract documents; preparing permits; and providing design support during contruction. An EAP with inundation mapping and O&M Manual were also prepared.
McCormick Taylor also completed environmental studies for the Final Scope Development (or Preliminary Design Phase) and Initial/Final design phases of the project. Under the Preliminary Design Phase, NEPA documents were prepared including Categorical Exclusion, Section 106 Studies, a Hazardous Waste Screening and endangered species investigations. Section 106 Studies entailed a Phase I Archaeological Survey and a Historical Structures Survey.
The Result
McCormick Taylor completed the final design and preparation of contract documents for the rehabilitation measures, including a semicircular concrete ogee spillway and apron, reinforced concrete training walls and wing wall extensions, concrete bridge repairs, and a permanent sheet pile cutoff wall. To accommodate NJDOT's aggressive project delivery requirement, McCormick Taylor completed the preliminary and final design in three and a half months rather than the originally established schedule of 18 months and obtained the NJDEP Dam Safety Permit in two weeks versus the typical three months.
Malaga Lake Dam received ACEC/NJ's Distinguished Award for Engineering Excellence (2004).
