The Detroit Water and Sewerage Department (DWSD) has requested proposals from consultants for engineering services in connection with the preparation of geotechnical and design reports for a proposed combined sewer overflow retention tunnel facility that stretches for nearly 13km. The Upper Rouge CSO tunnel is required to have a minimum 680M litre capacity and run through differing strata underneath a watercourse. The conceptual work carried out to date favours a rock tunnel of up to 8.8m finished diameter, running at invert depths of between 30m – 60m below surface. The scheme is part of DWSD’s plans to reduce discharges into the Rouge River and will intercept, store and dewater overflows back into the collection system from 17 outfalls that have historically discharged into the river. Requests for proposals must be submitted by 26 May and further details of the submission criteria, together with a complete description of the project are available on the DWSD website www.dwsd.org
