Interior view of Mainstream tunnel in early 1985 prior to the tunnel being placed in service. The pipeline at right and lighting are temporary for construction. The stairs at left show the entrance to the tunnel of the bottom of a drop shaft, commonly referred to a boot. The stairs are the toe of the boot, whereas, the bottom of the shaft, not in view, is the heel of the boot. The tunnel is lined with concrete throughout. (MWRD photo dated 1985)

September 25, 2013. Flanked by the Sanitary & Ship Canal at right and the Des Plaines River and Interstate Route 55 at left, McCook Reservoir is taking shape. In center, Stage 1 rock mining to create the reservoir void is three years from completion and removal of stage 2 overburden in the foreground is near completion. Mined rock is crushed and leaves the site through a tunnel to the Vulcan quarry off to the left where it is further processed for sale. (MWRD photo 13_0925_1095)

August 23, 2017, Mainstream tunnel 33-foot diameter outlet into McCook Reservoir under construction. The outlet invert is about 20 feet above the concrete slab. The slab contains numerous concrete blocks, integral with the slab, to dissipate the energy in the flowing water entering the reservoir. Once the water level in the reservoir rises above the crown of the outlet, the jet will be submerged and energy will be dissipated by turbulence in the reservoir. (MWRD photo 17_0823_153)

November 30, 2017. Des Plaines tunnel 20-foot diameter outlet into McCook Reservoir, recently completed. The invert is 42 feet above the concrete pad with splash blocks. To the left, an unexcavated portion of bedrock was intentionally not removed due to spalling rock above near the top of the reservoir rock wall. Blasting for removal was deemed a potential danger. (MWRD photo 17_1130_113)

June 24, 2015. Mayfair Reservoir has recently undergone an expansion to increase its flood storage capacity to provide additional protection to the surrounding residential neighborhood. Reservoir slopes were recently seeded and completion of the dry bottom with underdrainage is in progress. (MWRD photo 15_0624_0369)

July 20, 2015, looking north. The inlet spillway for Northlake Reservoir is in the background at right. The pumping station is out of view to the right, straddling Addison Creek. This reservoir is designed to maintain a permanent pool during dry weather. (MWRD photo 15_0720_0585)

The inlet spillway for the Silver Creek Reservoir is at right and the pumping station sits atop the slope at left. The creek flows from right to left in the background in this west facing view. This reservoir has a dry bottom and can be used in dry weather for recreation. (MWRD photo 15_0720_0552)