Central Arkansas Water begins hydrilla control steps at Lake Maumelle

The board of commissioners for Central Arkansas Water (CAW) recently approved a 10-year, $700 million infrastructure improvement plan that will include upgrades to the Jack Wilson Water Treatment Plant, a new raw water line from Lake Maumelle to the Wilson Plant, and a planned reservoir management program.

The reservoir management program is described as “aggressive” to control plant and algae growth and improve the overall ecological health of Lake Maumelle for future generations. Lake Maumelle, located in northwestern Pulaski County about 20 miles from downtown Little Rock, is the primary drinking water source for more than 500,000 CAW customers in eight counties. It was built in the 1950s.

An invasive species called Hydrilla has entered the lake. It grows from the lakebed as large stalks that reach the surface of the water, up to 30 feet tall. These beds of Hydrilla create large mats of thick green vines on the surface that can but do not currently house harmful Cyanobacteria on the leaves. These algal blooms can wreak havoc on the drinking water process and, if left untreated, can potentially harm waterfowl that eat the leaves.

To combat the areas of Hydrilla growth, CAW began a drawdown of the lake starting near the end of October. This drawdown exposed some patches of Hydrilla to the winter elements, hopefully aiding in its remediation. This is a typical process among lakes in Arkansas, with many scheduling drawdowns annually.

The next step in the process will be the application of a low-concentration herbicide, Fluridone, a systemic herbicide used to manage underwater plants and commonly used for Hydrilla control.This herbicide has been proven safe and effective for Hydrilla removal in numerous drinking water sources across the U.S.

This process will begin in mid-to-late April once the water temperature is high enough for the Hydrilla to begin growing again. During three different 4-5 day application processes, Lake Maumelle will be closed to boats, but it will be open as usual between applications.

CAW says customers will see no change in the taste or quality of water coming into homes and businesses, as the water will still go through the normal water treatment process between when it was drawn from the lake and arrived at the faucet.