Lake Le-Aqua-Na is a 39.5 acre (16.0 ha) recreational impoundment located in Le-Aqua-Na State Park, Stephenson County, Illinois. The lake is owned and managed by the Illinois Department of Conservation (IDOC). A Phase I diagnostic/feasibility study, conducted in 1981 under the Federal Clean Lakes Program identified the following major problems in the lake: high nutrient levels, nuisance algal blooms, excessive aquatic macrophytes, hypolimnetic oxygen depletion, and high turbidity and sedimentation. A management plan was recommended which included aeration/destratification, macrophyte harvesting, periodic algal treatment, and watershed treatment. The plan was implemented and intensive monitoring of the lake and tributaries was conducted by the Illinois Environmental Protection Agency with funding provided by a National Agricultural Conservation Program Special, a State ACP Special, and a Clean Lakes Phase II grant from the United States Environmental Protection Agency.