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Lake Manager's Report — July 2021

1. Northern McHenry County is still the ONLY location in the entire eastern United States that is under extreme drought. According to data released by the National Weather Service, the month of June 2021 was the fourth-hottest June ever recorded in Chicago’s history. Based on long-term climate averages, from April 1st to today, the amount of expected rainfall at Wonder Lake would be 13.7 inches. Instead, for this same period, the USGS rain gage at Thompson Road only recorded about 6.1 inches.

Lake Manager’s Report – June 2021

1. As everyone knows, most of McHenry County is experiencing a severe drought. Based on long-term averages, over the last two months, the amount of expected rainfall would have been over 8.5 inches. Instead, the USGS rain gage at Thompson Road only recorded 1.75 inches of rain over that two-month period. This lack of rainfall, which is even more extreme in the Nippersink Creek watershed above Wonder Lake, has resulted in the stream flow into Wonder Lake dropping from an average of around 60 cubic feet per second (CFS), to less than 18 CFS.

Lake Manager’s Report — May 2021

1. On April 15th, with the cooperation of the Woodstock Fire/ Rescue District, the Wonder Lake Fire Protection District and Hebron-Alden-Greenwood Fire Protection District performed a controlled burn at the Wonder Lake Sediment Drying Facility on Greenwood Road. Conducted as a FPD training exercise, this burn was done at the request of the MPOA, to burn off undesirable vegetation growing in the highly fertile dried sediment. Thanks to all involved for getting this accomplished.

Lake Manager's Report — April 2021

1. The three islands on the east side of the lake (O’Brien Shoals North & South and Wickline Island) previously had rip-rap installed offshore as a collar to help break up wave action before hitting the unprotected shoreline soils. While these practices have been very successful in creating quiet water areas, there is still more work needed. We are beginning to explore developing plans for adding additional erosion control protection around the islands, removing undesirable vegetation while replacing it with desirable native species, and improving fishery habitat.

Lake Manager's Report — March 2021

1. Lake users are reminded that with the recent thaw, any remaining ice surface should be considered unsafe.

2. In addition to the state-required annual inspection of the Wonder Lake Dam, the MPOA has retained the engineering firm (CBBEL) that conducts those inspections to also prepare a report on the Wonder Lake Dam and Spillway. The scope of that study is provided below. A draft version of that report has been received, and is currently under review, it is hoped that the final report can be available for distribution in the next month or so.

CBBEL SCOPE OF SERVICES

Lake Manager’s Report – February 2021

1. Lake users are reminded that with the deeper water now present in the dredged portions of the lake, ice formation on the lake can be inconsistent, particularly where streams flow into the lake. Please use caution accessing the lake unless you are positive of safe ice conditions.

Lake Manager’s Report – October 2020

1. The annual inspection of the Wonder Lake Dam and the Wonder Lake SDF was conducted by the MPOA consulting engineers on Friday, October 9th. The engineers were pleased with the concrete repair work that was done on the spillway during the Fall 2019 lake drawdown. Their summary report will be forwarded to the IDNR-OWR, as required.

Lake Manager’s Report – February 2020

  • Lake users are reminded that with the deeper water now present in the dredged portions of the lake, and the recent variations in temperature, ice formation on the lake so far this winter has been unpredictable at best. Please use extreme caution attempting to access the lake, unless you are positive of safe ice conditions.
  • Another feature of our current winter has been a number of ice events, which can make moving about safely a bit of a challenge.

Lake Manager’s Report – December 2019

1. The 2019 drawdown of Wonder Lake is now officially over. As of the beginning of December, water again began flowing over the dam spillway, allowing the sluice gates to again be fully closed. It is still expected that the lake level will still rise a bit more, as it usually maintains a normal pool from 3 to 6 inches above the spillway crest.

Lake Manager’s Report – November 2019

1. Despite the challenges posed by the heavy rains and early cold snap this fall, the MPOA contractor successfully wrapped up their repairs to the Wonder Lake dam spillway. In order to get to where the spillway leaks originated, the lake had to be temporarily drawn down roughly 5 and ½ feet. Concrete repairs were then completed on both the interior and exterior surfaces of the dam spillway where the minor leaks had been observed.

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