Central Arkansas Water Begins $40 Million Reservoir Management Program

News & Updates

LITTLE ROCK, Ark. – Central Arkansas Water (CAW) is embarking on an aggressive new reservoir management program 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 specifically to provide drinking water and has provided some of the best drinking water in North America for decades. CAW was recognized as top five best-tasting drinking water in North America by the American Water Works Association only two years ago.

Lake Maumelle continues to produce fantastic water, but the dynamics of reservoirs change over the years, and now is the time for CAW to prepare the lake for future generations. This proactive approach to reservoir management will ensure fantastic water for CAW customers for decades to come.

The CAW Board of Commissioners recently approved a 10-year Infrastructure Improvement Plan which will pump almost $700 million into existing CAW infrastructure, including upgrades to the Jack Wilson Water Treatment Plant, a new raw water line from Lake Maumelle to the Wilson Plant, and this planned reservoir management program.

The protection of Lake Maumelle has been and remains one of the highest priorities for CAW, which is why the first major project in the Infrastructure Improvement Plan is the mitigation of an invasive species that has entered the lake.

This species, called Hydrilla, 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. This was documented in Arkansas in the late 90s when almost three-dozen bald eagles died near DeGray Lake because they were eating infected waterfowl from an algal bloom there.

Lake Maumelle now has Hydrilla growth in areas of the lake with water depths up to 15 feet. The growth is most dense in the lake’s western end in shallow depths. Since it can reproduce by fragmentation, it

would only take a few pieces traveling underneath a boat from another lake to create a potential problem.

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 is dropped into the lake as a pellet and sinks into the lakebed, where it is absorbed by plant shoots and roots. Once absorbed, the herbicide interferes with chlorophyll production within the plant. Without chlorophyll, the plant is unable to photosynthesize, which causes it to starve and die.

This herbicide has been proven safe and effective for Hydrilla removal in numerous drinking water sources across the U.S. Many water systems across the country have used it in this fashion because it is so safe. Since it works by interfering with photosynthesis, it only affects the targeted plant life and does not affect animals or humans. It is so safe that it can be touched by human hands without any protective equipment.

This process will begin in mid-to-late April once the water temperature is high enough for the Hydrilla to begin growing again. During the application process, Lake Maumelle will be closed to boats. This closure is not due to the herbicide, but rather to ensure that the application areas are clear so crews can safely apply the product without having to dodge additional boat traffic. Three separate treatments are scheduled 30 days apart, and the lake will be closed when the Fluridone application occurs. Each treatment will take four to five days, and is planned to be completed on weekdays. The lake will be open as usual between applications.

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.

Additional steps, as needed, could include the future dredging of the lake to improve water quality while restoring water volume. More information will be provided to CAW customers and stakeholders if any additional steps are taken.

CAW’s purpose is to protect public health by providing outstanding water services. This program does exactly that by improving and protecting our most valuable resources to ensure future generations’ health. CAW is proud to deliver high-quality, affordable, abundant, dependable water services every day. Anyone with questions about this program can contact our Water Quality department at 501-210- 4914, or email communications@carkw.com.