Project Description

The north lobe of the existing Thornton Quarry, currently owned by the MWRD, was converted into a composite reservoir. A 116-foot-tall Roller-Compacted-Concrete dam was constructed below Interstate 80 to separate the north lobe from the rest of the quarry and several tunnels connecting the north lobe to other portions of the quarry were plugged. This reservoir was connected to the MWRD’s Deep Tunnel system by a tunnel extension. A single 30 ft. I.D. concrete lined tunnel starting from the existing tunnel stub and extending for several feet was bifurcating into the reinforced concrete wet well gate shaft. Four wheel gates will regulate the flow through the wet well. The bifurcated tunnel continues downstream and re-combines into a single 30 foot I.D concrete tunnel, before exiting to a tunnel portal and diffuser apron in the composite reservoir. The tunnel bifurcations, the transition sections and the gates’ chambers are steel lined. KMI’s role was the structural design of the two tunnel bifurcations, and the lower portion of the reinforced concrete wet well. During the construction phase, KMI, as a member of the DOR team, oversaw the fabrication and installation of the steel liner and the surrounding reinforced concrete lining to verify compliance with the design documents. In addition, KMI assisted with the oversight of the QA/QC procedures for the construction phase of this roller-compacted-concrete dam and tunnel plugs