Master Drainage Studies

Project Location: Village of Lindenhurst; Village of Amityville; Hamlets of Bellmore, Merrick, Seaford, and Wantagh; Bay Park and Village of East Rockaway
Client: Village of Lindenhurst, Town of Babylon, Town of Hempstead, Nassau County

In 2012 Superstorm Sandy overwhelmed Long Island’s south shore storm water drainage systems.  Floodwaters inundated roadways, homes, schools, Municipal buildings, and businesses and made streets impassable and areas unusable. The State of New York established the NY Rising Community Reconstruction (NYRCR) Program empowering the “most impacted communities with the technical expertise needed to develop thorough and implementable reconstruction plans to build physically, socially, and economically resilient and sustainable communities.” Municipalities were eligible for US Housing and Urban Development (HUD) Community Development Block Grant-Disaster Recovery (CDBG-DR) funding for disaster recovery projects, with funding delivered through the NYRCR Program.

Nelson + Pope was retained by various municipalities to provide Master Drainage Studies of the drainage infrastructure and potential projects to mitigate the stormwater and tidal flooding.  These Drainage Studies included the preparation and development of Comprehensive Drainage Infrastructure Master Plans under the supervision of the New York State Governor’s Office of Storm Recovery (GOSR) for the Village of Lindenhurst, the Town of Babylon, the Town of Hempstead, and Nassau County Department of Public Works.  These Master Plans assessed the existing drainage infrastructure condition including structures, pipes, outfalls, and bulkheads; identified system capacities and limitations; developed alternatives to diminish the risk to public and private properties and infrastructure; and provided a hierarchy of feasible alternatives to mitigate stormwater and tidal flooding based on cost to construct, public impact, long term sustainability, and resiliency benefits. The alternatives were presented at Public Information Centers to obtain community input that influenced the municipality decision of alternative selection.  Some of these studies included the development of preliminary (30%) design plans for the municipality’s selected alternatives identified in the Master Plan and supported by the community.

Traditionally, duck bill check valves were installed on outfall drainage pipes located in the bulkheads behind private residences which posed difficulties with maintenance and inspection and the duck bill check valve extending beyond the bulkhead inhibiting boat traffic in and around the check valve.  The recommended projects were unique in the fact that they proposed new drainage structures located on municipally owned streets with inline check valves in the downstream pipe.  No longer will municipal maintenance crews need to be on private property to inspect or maintain the check valve nor will the check valve inhibit boat traffic.  In addition, by proposing a stormwater treatment structure upstream of the new check valve debris and oils from the road runoff would be removed, cleaning the stormwater prior to discharge into the adjacent canal and also to remove debris that may make clog or damage the check valve and make it inoperable.

N+P completed Comprehensive Drainage Infrastructure Master Plan for the Village of Amityville, Town of Hempstead (Hamlets of Bellmore, Merrick, Seaford, and Wantagh), Nassau County Department of Public Works (Bay Park and the Village of East Rockaway) and the Village of Amityville.

Relevant Project Components:

  • Topographic/Existing Conditions Survey and Mapping
  • Inventory of Drainage Infrastructure
  • Wetland Identification
  • Potential Environmental Permitting
  • Public Information Center
  • Stormwater Management and Tidal Backflow Treatments
  • Preliminary (30%) Design and Construction Costs