Koonz & Beaulieu Lake Association

You've probably seen the numbers on our Lake Status page and wondered, "who's actually out there, and what are they doing?" Short answer: members, with a white disk, on a schedule. Here's the whole picture.

The volunteer program

Koonz and Beaulieu are monitored by the Association's volunteer program. Trained members sample on scheduled days through the season — the same stations, the same methods, so that a reading this year can be compared honestly with a reading last year. Consistency is the whole point: a single number is a snapshot, but a season of numbers is a trend, and trends are what we manage the lake by.

The program's outputs are the three numbers on our Lake Status page — Secchi depth, phosphorus, and chlorophyll-a — plus the supporting measurements (temperature, pH, dissolved oxygen, and more) that go into the full water-quality report.

The Secchi disk: our simplest, best tool

The Secchi disk is a 10-inch disk — white on top, black-and-white quadrants on the bottom — tied to a graduated rope. From a dock or a boat, you lower it slowly into the water and watch. You note the depth where it disappears from sight (looking straight down, not at the rope) and where it last reappears as you lift it. The Secchi depth is that disappearance point, in feet.

It sounds almost too simple. That's the point — a Secchi reading takes minutes, costs nothing, and compares directly to readings taken decades ago or at other lakes.

What it tells us: clarity — how far light penetrates before the water gets milky or green. More algae, more suspended silt, or a churning storm all push the number down. A higher number means clearer water, which is what most of us think of as "the lake looks like the lake."

What it doesn't tell us: a Secchi reading is a snapshot of one spot, one minute. Wind, a recent rain, or a busy boating weekend will move it. That's why we sample the same stations on the same schedule and read the season, not a single day.

Sampling stations

We sample from a small set of fixed stations around each lake — chosen so the readings represent the lake as a whole rather than one dock's experience. The exact locations are held by the monitoring coordinator so that volunteers keep going to the same water, year after year.

Why fixed stations? Because comparison is the whole game. If we wander around the lake, a "worse" reading might just be a shadier cove. If we stay put, a real change in the water shows up as a real change in the number.

What we measure, and why

Each visit collects a small battery of measurements. A few of the main ones:

Secchi depth — the clarity snapshot, described above.
Phosphorus — the nutrient that fuels algae; we send water samples to a lab for this one. Lower is better, and it's the number the Association watches most.
Chlorophyll-a — a lab measurement of the algae currently in the water; our "algae proxy."
Temperature and dissolved oxygen — usually by profile (a few depths), to see how the water column is layered and whether the deep water has enough oxygen for fish.
pH — a quick check that the water chemistry is in a healthy range.

What happens to the numbers

Readings are entered into the Association's records and rolled up into the water-quality report — the full history, yearly averages, and both lakes side by side. That report is what the board uses to judge whether the lake is improving, holding steady, or slipping, and it's what we share with the DNR when it's useful to do so.

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