Explanation
1. BACKGROUND:
A. Need. This legislation authorizes the Director of Public Utilities to enter into a construction contract with Complete General Construction Company, in connection with the Berliner Park Storm and Sanitary Improvements. The purpose of this Project is to make improvements to sanitary and storm sewers in and adjacent to Berliner Park. Sanitary and storm services in the park is provided by the Old Dry Flow Sewer which is nearly abandoned due to its poor structural condition with the exception of the sewer segment in the Berliner Park. The Old Dry Flow sewer is tributary to the OSIS, and during periods of high flows, can back up causing water in basements (WIBs) and overflows from manholes. The initial concept of providing gravity sanitary sewer connections for the Berliner Park facilities was found to not be feasible during project design. The proposed connection to the OSIS would have been very low in relation to the flow line of the OSIS and would have subject the connection to high backwater conditions during rain events. Reuse of existing sanitary sewer lines within the park would have required relining based on TV inspection of the lines during design. Draft operational plans for the treatment plants indicate the OSIS will be operated under a surcharged condition during severe rain events. Other alternatives were investigated but found to be very costly to provide sanitary service for such a limited number of facilities. The recommended alternative was found to be the installation of a grinder pump at each facility and a small diameter force main to a central collection manhole near an existing OSIS manhole. The grinder pump package includes a check valve on the discharge line to prevent backup from the receiving sewer. As a further safe guard, a sluice gate will be provided on the gravity sewer line from the collection manhole to the OSIS main sewer which could be closed during severe rain events. Several hundred f...
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