Mayfair Reservoir Information
Mayfair Reservoir & Pump Station
1975 Pump Station Design: The Mayfair reservoir was designed as a retention pond. Retention ponds are designed to have water in the bottom; Detention ponds are designed to have dry bottoms. The pump station has small dewatering pumps (DP). The village has made operational changes to the DP's to keep the bottom of the pond dry. This provides maximum flood storage and protection.
From an operational perspective dewatering the pond creates an extreme service load on the pumping system. The DP's frequently fail, as they were not designed to operate to keep the pond dry. It is likely that we will need to replace these pumps every 3 to 5 years. The last pump failure also burned out the electrical panel. Public Works is in the process of repairing the electrical panel so we can replace the dewatering pumps. Until those repairs are complete, about two (2) feet of water will remain. The two large pumps are still working to provide flood protection, but they can't work at the lower levels.
The 2016 Pond Design: The design of the bottom of the expanded reservoir is for some water to remain in the bottom. The pond is a retention pond and therefore is designed to hold some water. This was done for four reasons. 1) it is considered a Best Management Practice (BMP) to have a natural area in the pond. This natural area will absorb many of the chemicals that end up in the pond from roadway drainage. Chemicals that come into the pond from a storm include chlorides from road salt, zinc from motor oil, chromium from chrome plating to name a few. A small natural wet area breaks down this chemical mix before it is going into Salt Creek yielding a natural water treatment effect. 2) Our MS-4 permit from the IEPA favors the Village treating storm water discharge in some fashion prior to release to Salt Creek. The design reflects the need to treat our discharge before it enters into the Creek. 3) There are natural springs in the pond area. To keep a dry bottom pumps have to be designed to run constantly. That is not an efficient use of energy or an environmentally friendly practice. 4) The pond bottom is only a few feet above hard rock. When the space between the rock and pond bottom gets full of ground water, the pond bottom would be wet again, filling with the area ground water table. The ground water table is measured in square miles and that large volume of water would flow to this location if we began to pump.
The older section of the pond is kept dry by an under drain system. While the pumps for that system run all the time and burn out frequently, the ability to connect the new system directly to the old system was not possible. PW is reviewing ways to indirectly connect the new section into the under drain system.
As to the mosquito problem; We currently use a chemical called Altosid for mosquito lava abatement. The application is done by the mosquito abatement district. We place the chemical into all our catch basins thought the village. The natural area in the bottom of the old pond where the cat tails grow is the home of several species of dragonflies. They eat their weight in larva every day, as do several species of birds. We do not use Altosid in the pond as it may harm the dragonfly and birds.