Lake Munson in Tallahassee, Florida

Lake Munson is the focus of a long cleanup because it sits at the bottom of a large share of Tallahassee's drainage.

A 2022 Leon County agenda item describes it as an approximately 288-acre, cypress-rimmed lake south of the city, 0.45 square miles with an average depth of 5 feet, that was believed to be a cypress swamp before it was impounded and now functions as a shallow man-made lake. It receives surface water from a 32,000-acre basin, much of it in the City of Tallahassee, and all flow enters the lake through Munson Slough from Lake Henrietta.

The same Leon County report calls Lake Munson a state-managed waterbody with a history of chronic water quality and ecological problems, including fish kills, algal blooms, exotic vegetation and snails, high nutrient levels, low game fish productivity, sediment contamination and depressed oxygen levels.

The county's spending figures differ by page. Its June 2025 update says local governments have invested over $291 million since the 1980s and completed more than 29 projects and 21 best management practices, while the county's Investments in Lake Munson page gives more than $290 million in total, including more than $247 million on 21 capital projects, seven ongoing projects totaling over $42.5 million, and 12 best management practices.

Lake Munson was polluted by decades of runoff and wastewater flowing down from Tallahassee.

The 2022 county report says development in the Tallahassee red-clay hills, wastewater treatment facilities discharging to the tributary system and drainage built for flood reduction carried heavy nutrient loads into the lake and embedded legacy nutrients in the lake-bottom soil.

The largest wastewater source was rerouted decades ago. In the early 1980s, effluent from the City of Tallahassee T.P. Smith Water Reclamation Facility was redirected from Munson Slough to the Tram Road Sprayfields, and the county says T.P. Smith effluent no longer reaches Lake Munson directly or indirectly.

The bottom still holds a record of that history. Between September and November 2018 the Florida Geological Survey took vibracore sediment samples at 37 sites, 32 of them in Lake Munson, and its February 2019 report found polychlorinated biphenyls and heavy metals in the samples. The county says that, as a result of that and a later study, in-lake sediment removal is no longer a viable option for reducing nutrients in Lake Munson at this time, though dredging may become viable with new technologies.

Most of the cleanup was built upstream, in Tallahassee's drainage ditches and ponds.

The 2022 county report says the Northwest Florida Water Management District, under a joint contract with Leon County and the City of Tallahassee, completed a Stormwater Management Plan for Lake Munson in 1991 that recommended seven regional wet detention facilities, and that a twelve-member Lake Munson Action Team wrote the 1994 Lake Munson Action Plan around watershed management, in-lake restoration and community action.

The Lake Munson Restoration Project built the Lake Henrietta stormwater facility, improved Munson Slough, removed trash and the sediment delta from Lake Munson and restored wetlands around both lakes. Trash racks stand east of Jake Gaither Golf Course on the East Drainage Ditch, west of Lake Bradford Road on the Central Drainage Ditch and upstream of Lake Henrietta, and regional facilities include Carter Howell Strong Park in Frenchtown at the headwaters of the FSU Branch and the FSU facility known as Lake Elberta. Blueprint's stormwater work along the Capital Cascades Trail corridor totals more than $130 million and stretches about 2.5 miles, the county says.

Lake Henrietta is now due for its own cleanup. The June 2025 update says the facility has captured over 53,000 cubic yards of sediment and debris since its construction in the early 2000s, and that Leon County was awarded a U.S. Environmental Protection Agency grant for the Lake Henrietta Sediment Removal Project, alongside a planned Munson Slough Embankment Repair project and ongoing septic-to-sewer conversions in the basin. The update also says FDEP set a Total Maximum Daily Load for Lake Munson and Munson Slough above the lake in 2013, with nitrogen and phosphorus targets.

The most recent Lake Munson drawdown ran from November 1, 2022 to May 17, 2024, according to the county's drawdown page.

The June 2025 update says Summer 2022 brought Lake Munson an algal bloom, rapid growth of invasive aquatic vegetation and a fish kill, and the September 2023 update notes that routine drawdowns had been done approximately every ten years to let the nutrient-rich sediment dry out and form a cap.

Sources: Leon County Lake Munson Drawdown page, September 2023 update, April 2024 update.

The April 2024 update says the December 2023 gate closure kept Lake Munson full into January 2024, which reduced sediment drying for that period but let water hyacinth seeds germinate before a cold spell and the renewed drawdown killed them off.

In June 2025 Leon County reported that water quality in Lake Munson and Munson Slough remained near or below state standards and was improving.

The June 2025 update says nitrogen in Lake Munson stayed consistently below the state target, phosphorus steadily declined toward it, and the state's nitrate target at Wakulla Springs continues to be met.

The Leon County update lists approximately 250 acres of open water on Lake Munson, invasive vegetation coverage down about 38 percent from July to November 2024 and about 11 percent from March to April 2025, and no algal blooms reported to FDEP or observed by county staff since the refill. It also reports sightings of Everglade snail kites, a federally endangered species historically limited to central and south Florida, which county staff are monitoring with FWC.

Looking ahead, the county says routine periodic drawdowns every five to 10 years will be used for sediment management, and its 2025 update scheduled the next Lake Munson status report for June 2026, at the end of the two-year Post-Drawdown Water Quality Study.

Southside residents organized as a Lake Munson Workgroup have pushed the county to do more in the lake itself.

The 2022 county report says the Lake Munson Workgroup supported the planned drawdown but felt very strongly that it should be paired with sediment removal while the lake was dry, and asked for a peroxide algal bloom treatment called Lake Guard, which staff did not include because the drawdown removes the water the algae need.

Public access is at Gil Waters Park Preserve at Lake Munson, which the county says was built in 2000 with a boat ramp and landing, picnic areas, a scenic overlook, trails and paved parking. During the 2022 bloom the county closed the Gil Waters boat ramps at the urging of the Florida Department of Health while keeping the Leon County park open with signs, and the June 2025 update says the lake is now used for birding, fishing, hunting and boating.

Last verified: October 18, 2026, from Leon County's October 2022, September 2023, April 2024 and June 2025 Lake Munson agenda items and the county's Lake Munson Drawdown and Investments in Lake Munson pages.