The Erie County Water Authority (EWCA) owns and operates the Sturgeon Point Treatment Plant as a source of fresh water for thousands of residents of southern Erie County. During the construction of the plant, a tributary stream out-letting to Lake Erie was diverted into a 48-inch storm sewer running approximately 1,000 feet through and below the central part of the plant.
This drainage system was a consistent source of problems for the authority. Furthermore, the condition of the pipe, especially at its end sections, had deteriorated to the point where it needed to be replaced. Since the pipe ran under the main treatment plant, its replacement at this point would be impossible.
Therefore, the authority retained Erdman Anthony to review the drainage through this pipe and throughout the 90+ acre facility.
Erdman Anthony began the process with HEC-RAS computer modeling of the existing site drainage, drainage pipes, and open ditches. Through this study, several alternatives were created that allowed the authority to discontinue use of its troublesome 48-inch main drainage line.
The final project included:
- The reconstruction of over 3,000 feet of open drainage channel, including the installation of temporary erosion and sediment controls, excavation, and grading to shape the ditches to proposed grades and cross sections, installation of rip-rap-lined ditch sections, and the creation of stabilized grassed waterway sections.
- The creation of over 700 feet of new open drainage channel, including the installation of temporary erosion and sediment controls, removal of existing trees, excavation of test pits to verify existing utility locations, modification of existing utilities (including fiber optics and electrical power lines), removal of a large existing driveway culvert and concrete headwall, installation of new storm drainage (catch basin, manhole, pipe and end-section), installation of rip-rap-lined ditch sections, and the creation of stabilized grassed waterway sections.
- The installation of new twin 48-inch CMP culverts, including the installation of temporary erosion and sediment controls, sawcutting and removing pavement, excavation of test pits to verify existing utility locations, modification of existing utilities (including fiber optics and electrical power lines), complete excavation for new culvert pipes, installation of the new culverts, and restoration of the adjacent landscape areas.
- Entrance road and control building paving consisting of three different paving operations, ranging from applying an asphalt top course overlay for existing parking and staging areas to full reconstruction of the half mile-long entrance roadway.
- Modifying existing utilities, including installation of a new air release valve chamber and connections, relocating existing air release valves to the new chamber, extensive power-system modifications, relocation of existing CCTV cameras, installing new fiber optics for the CCTV system, and adjusting numerous rim and grate elevations.
Since this drainage system outlets directly into Lake Erie, extensive permits and coordination were required with the U.S. Army Corps of Engineers and New York State Department of Environmental Conservation. All the drainage work was designed in accordance with the USACE NWP Construction Best Management Practices requirements for nationwide permits. Furthermore, a Stormwater Pollution Prevention Plan was implemented in accordance with the NYSDEC SPDES General Permit for Stormwater Discharges from Construction Activities.
Erdman Anthony assisted the authority in obtaining bids for the project and recommending a successful bidder. Our firm also provided extensive engineering during construction and full-time on-site construction inspection for the duration of the project.
The construction was completed on time and under budget and has resulted in a smoothly operating, efficient site-drainage system for the authority.