The Buffalo Sewer Authority (BSA) routinely monitors and inspects its extensive system for collapses and issues that impede sewer flow. When the monitoring and inspection identified several spot-repair locations in the service area, site constraints including – but not limited to – large-diameter water mains in close proximity to the sewers prevented the use of existing emergency-repair contracts to conduct the repair work.
Due to the repairs’ complexity and the potential need to replace the aforementioned water mains, engineering drawings and specifications were required.
BSA retained Erdman Anthony as part of our term agreement with the agency for our expertise in this type of work and for our previous experience with the City of Buffalo Department of Public Works’ water division.
Initial phases of the project included reviewing the televised sewer tapes of the existing sewers to determine their conditions and lateral locations; investigating the subsurface extensively to determine soil, pavement, and rock conditions; detailed review of existing sewer plans; retrieval of water line-record documents; topographic survey; and coordination with utility companies.
The final project consisted of replacing 475 feet of 21-inch sewer on Central Avenue; replacing 1,600 feet of 10-inch sewer and eight-inch water line on Chelsea Place; installing 350 feet of 15-inch sewer on West Delavan Avenue; replacing 300 feet of 15-inch sewer on Roseville Street; installing 325 feet of 10-inch sewer on Windsor Avenue; and replacing a 24-inch sewer on Seneca Street, along with manholes, laterals, restoration, and all appurtenant work.
Of special note in the design was the work on Chelsea Place. The high rock stratum meant that when the existing water and sewer lines were installed in the early 1900s, both were put in the same trench, in close proximity. In order to avoid excessive cost and disruption to the neighborhood, it was decided to place the new water and sewer lines in the existing rock trenches.
This plan required extensive meetings and coordination with the Erie County Health Department to obtain a variance from the Ten State Standards water-and-sewer separation regulations as part of the permit. The permit required several special construction methods, including utilizing pressure-pipe designs for sewer pipe and manholes, in order to minimize the potential for future leaks and cross-contamination.
In addition to this effort, special considerations were required on Central and West Delevan avenues.
On these streets, the new sewer will be placed in close proximity to the existing 1900s-vintage 36-inch watermains.
The protection and continued operation of these mains are critical to the city’s water supply. Therefore, the contractor installed sheeting along the sewer trench to protect these facilities.
All of these efforts required close coordination with – and combining the contract document requirements of – BSA, the Department of Public Works, and the Buffalo Water Board.
In addition to the design, Erdman Anthony provided construction administration and full-time on-site construction inspection for this project.