Officials are lowering the water level of a lake in northeast Iowa to help control the spread of an invasive aquatic plant.
The state Department of Natural Resources says it began lowering the water level Monday at Martens Lake in the Sweet Marsh Wildlife Management Area. The water will be returned in the fall.
The drawdown will expose brittle naiad plants and its seeds. The plant, which was found in the lake in 2010, is considered challenging to control once it's established. Officials say air kills the plants that have been germinated and suppresses germination in seeds.
Officials say visitors can still fish and view wildlife in the area during the drawdown.