MEMORANDUM

From: Board of Trustees
To; Residents of Dougherty Lake Subdivision
Subject: Aeration of Lake – Analysis of Conditions and Conclusion
Date: July 17, 2021

Dear Residents:

Our Lake Trustee, Sterling Wallace, has diligently been evaluating the aerators in the
lake, one of which failed earlier this year. Below is the analysis he undertook and the
conclusion he has drawn with input from all the trustees but also from former lake
trustees.

This May, the second fountain aerator failed due to debris. This is probably the fourth
failure in the last 8 years. Each one costing thousands.

Fountain aerators have proven costly to maintain, costly to operate, and costly to replace
every time they fail. So we spent over 6 weeks investigating replacing the fountain style
aerators with a different type. Effective aeration is critical because it puts oxygen into the
water and circulates water between layers of the lake. This improves the health of the
lake and it’s fish life

We have a proposal from Missouri Machinery & Engineering (MME) for a “diffuser”
style aerator system.

The advantages:

• This method is more efficient at oxygenating (more oxygen).
• It is better at circulating water between the colder deeper water and the warmer surface.
• It will use about 1/3 of the energy.
• Easy to install and maintain because the motor is located on shore.
• They do not suck up lake water, thus they do not suck up lake debris and get damaged.
• Healthier and safer for fish & wildlife.

The estimate for energy cost (based on 2020 bills) is $4,300 to run the aerators for 8
months. That is with operating hours adjusted down for 4 of the 8 months.
The calculation for the energy cost of the diffuser system for the same 8 months is
$1130….total for the 8 months.

Energy usage is a significant factor. Plus, it impacts more than just energy cost. The
other factor is the toll that high current demand takes on the control panel. It has caused
premature failure of the circuit breaker panel in the control panel.

It became painfully obvious that it would be foolish to put more money into the current
fountain aerators. Replacing just the south aerator would be over $10,000.

So in discussion with past and present lake trustees, your Board has unanimously
approved the recommendation and action thereon.