Christina River Force Main

JMT performed engineering services for the Christina River Force Main (CRFM), which serves more than 55% of Delaware’s population and is a critical wastewater transmission system serving areas south and west of Wilmington. The system conveyed approximately 50 MGD of untreated sewage on an average day. There was no redundant transmission system for any of the CRFM flows; therefore, it was critical to maintain the continuous, uninterrupted operation of the CRFM.

The aging prestressed concrete cylinder pipe (PCCP) was prone to failure from corrosion and material defects. Its large size, up to 84-inch diameter, and constant pressure made any leak a serious threat to the sensitive ecosystem of Churchman’s Marsh which it crosses.

JMT developed a risk model with both short-term and long-term recommendations to provide uninterrupted service to this large population while protecting the unique environmental assets. The team evaluated innovative testing methods such as “free swimming” devices in the live pipe to measure and record breaks in prestressed wires or large holes in the steel cylinder using electromagnetic technology, as well as exterior testing evaluating mortar condition and wall thickness.