HOT SPRINGS, AR (News release) - The annual drawdown of both Lake Hamilton and Lake Catherine will be 3 feet and will begin Nov. 1. Lake levels will be reduced about 6 inches per day, and the drawdown will be complete on both lakes by Nov. 9. The water released at the dams will be used to generate emission-free, low-cost hydroelectric power. Both lakes will return to their normal summertime levels in March 2015.
In addition to facilitating shoreline facility maintenance and inspection, the annual drawdown is part of a plan to help control nuisance aquatic vegetation. Entergy Arkansas coordinates the annual winter drawdown with the Arkansas Game and Fish Commission. Fisheries, vegetation, facility management and downstream water needs are the key factors considered in deciding the drawdown’s depth and timing.
Recent inspection shows that there has been some decrease in many species of nuisance vegetation. Both southern naiad and Eurasian water milfoil have declined after being exposed to colder temperatures last winter and because the water has been less clear as a result of higher-than-normal rainfall. Algae, unfortunately, is as problematic as ever, particularly in shallow areas. One type that’s thriving is filamentous algae, which is long, stringy and moss-like. It begins its growth on the lake bottom or water’s edge and can form floating mats. The other type of algae that is still plentiful in some areas is Chara. It grows more like a weed and is also known as “muskgrass” because of its musky smell.
Entergy’s Nuisance Aquatic Vegetation Management Plan, developed in 1997, identified lake level drawdowns and stocking grass carp as the primary methods of attacking the problem. Areas of the lakebed dry out to varying degrees due to runoff and natural springs. Freezing temperatures will impact the vegetation’s root system more when the lakebed is drier. Different species of vegetation are more sensitive to freezing temperatures and drying of the lakebed during drawdowns. Unfortunately, algae is not one of them. In response, the Arkansas Game & Fish Commission released approximately 1,900 young grass carp into Lake Hamilton this summer. The last time grass carp were released into Lake Hamilton was in 1999. Grass carp do not reproduce in our lakes and as they age they tend to be less effective in controlling aquatic vegetation.
Vegetation management is challenging. Many factors influence the effectiveness of any one management technique. Water clarity, temperature, moisture, nutrients from runoff, and other variables all play an important role. “Lakefront property owners can help by not over-fertilizing their yards or over-watering when they do. This will help reduce nutrient runoff and reduce algae growth,” said Bobby Pharr, manager of Entergy Arkansas hydro operations. “Be assured that Entergy Arkansas and the Arkansas Game & Fish Commission are aware of the issue, are engaged in the battle, and will continue executing a long-term strategic plan to manage aquatic vegetation in lakes Hamilton and Catherine.”
Boaters should use caution while on the lakes during the drawdown period because there will be more shallow areas, and winter rains can increase the amount of debris washed into the lakes. Owners of boats and floating docks should also take precautions to ensure they are able to adjust to the drawdown. Failure to do so may cause damage to them. Some docks will be able to rest on the lakebed with little or no problem. If the shoreline is steep or rocky in a particular area, dock owners may need to temporarily move docks to deeper water. If relocating a dock, be sure it does not restrict navigation or become a boating hazard.
Entergy Arkansas will not require a permit for the temporary relocation of docks due to the drawdown, but the dock must be returned to its permitted location once the lake returns to its summertime level. Entergy Arkansas also recommends using a licensed electrician to make any alterations to wiring in conjunction with the drawdown.
Permits must be obtained from Entergy Arkansas for any construction on the lake or shoreline, including personal watercraft ramps, boat docks, piers, walkways, swim docks, landings, embankments, bulkheads, seawalls, rip-rap, dredging and filling operations. Changes in ownership, relocation, replacement, enlargement or significant alteration of existing facilities also require a new permit from Entergy Arkansas. The company’s guidelines are revised periodically, so anyone planning to build on Entergy Arkansas’ shoreline property should be sure to obtain the latest revision before proceeding.
Lakefront property owners needing further information on the drawdown schedule or shoreline permitting guidelines and applications for lakes Hamilton or Catherine can call Entergy Arkansas’ hydro operations office at (501) 844-2148 or visit the hydro operations website (click here). Visitors to the website may also subscribe to receive lake and flow information by email. To receive weekly information on the operation of the lakes, the public can “Like” hydro operations’ Facebook page (click here).
Lake Catherine is formed by Remmel Dam and Lake Hamilton is formed by Carpenter Dam. Both were built more than 60 years ago for hydroelectric generation. Lakes Hamilton and Catherine are part of Project 271, a hydroelectric project licensed by the Federal Energy Regulatory Commission. The license grants Entergy Arkansas authority to manage these reservoirs and related shorelines and operate Remmel and Carpenter dams. The license also requires Entergy Arkansas to control activities affecting the lakes’ environmental, safety and recreational values.
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