Warfield Relief Sewer
Fort Wayne, Indiana
Our Utility Infrastructure Group provided engineering services for the layout and design of a new 30-inch relief sewer capable of transmitting up to 17 mgd. The relief sewer was constructed to reduce/eliminate surcharge flows from the City of Fort Wayne’s City Utilities Department existing Warfield Relief Interceptor. The Environmental Protection Agency deemed that elimination of these overflows is an “early action project” as part of the City’s Consent Decree with EPA to eliminate or minimize such overflows throughout the City of Fort Wayne. As such, this became a fast-track project in order to meet the construction schedule mandated in Fort Wayne’s consent decree that includes approximately $240 million in projects to be completed over a 20-year period. The design of this project presented several challenges including determination of the route of the 6,000-lft interceptor.
The City completed flow monitoring and XPSWMM model development of the Interceptor to determine the relief sewer sizing and connection point locations. However, it was determined early on in the design process that the modeled route was not constructible. Therefore, American Structurepoint was tasked with making significant routing design revisions while still providing the necessary relief points (cross connections). This required significant coordination with the Owner and its modeling staff. In addition, the design included several innovative components such as multiple conflict and diversion structures and two triple-barrel siphon structures to transmit relief flow under an existing creek. The design also included significant site regrading, deep sewer construction, and installation of approximately 300 lft of 48-inch steel casing under US 27. The estimated cost of the improvements, completed in fall of 2011, was $1.8 million.