Dam Project

Dam History

  • The dam was built around 1928 – 1929; roughly 91 years ago.
  • The dam was never submitted or classified with the State of Illinois as a “constructed dam.” This led to confusion about its existence when petitioning to enable reconstruction.
  • The spillway opposite the dam has been deteriorating and could break through flooding Midlothian Road and adjacent communities downstream.

Project Details

  • Fremont Township is working to acquire permits from different government agencies.
  • The project will take approximately six (6) months.
  • Highland Drive will remain 14’ wide over the dam.
  • If there is any delay, it would be the result of utility or permitting issues. This is not anticipated, but always a possibility.

Project Benefits

  • All aspects of the Sylvan Lake water level (normal, winter and emergency) will be controlled by a state-of-the-art valving system, which will be managed by Fremont Township.
  • A 5-foot-wide concrete walkway will be created on the lake side allowing pedestrians to cross the dam safely
  • The spillway side of the dam will also be graded to have a 2.5:1 slope instead of the almost 5:1 slope that currently exists
  • Vegetation in the spillway will be cleaned up.  A low-profile “no-mow” type grass will be planted allowing for easier maintenance by Fremont Township.

Project Requirements

  • Highland Drive at Midlothian Rd will be closed to traffic for the entire project
  • The only community entrance/exit will be Crescent Drive at Gilmer Road for the length of the project.
  • Schools, Countryside Fire, Lake County Sheriff and all waste haulers will be notified of the single entrance/exit.
  • Nicor gas main, L.C. Public Works sanitary sewer and a Sylvan Lake water main all currently run within the construction zone.  All will need to be permanently relocated before the dam and spillway can be deconstructed 
  • Over a span of 1-2 weeks, the lake will be lowered from “normal” water level to approximately 6 feet.  This will leave the lake at about 50% of its normal size.
  • The reduction in lake level could result in some fish kill.
  • The lake level will remain reduced at about 50% of its normal size for the full length of the project. We are encouraging lakefront homeowners to make improvements to their seawalls and shorelines during this time. The Association will also look for opportunities to make improvements to Association property and will address any other issues with the lowered lake as necessary.

Bathymetric Diagram

In order to give you an idea of how “empty” the lake will be when it’s lowered, below is a depth diagram of Sylvan Lake.