Florida Watersheds Overview — Florida

Florida is officially divided into 29 named major watersheds, mapped at the HUC-8 hydrologic unit code level and organized into five large regional drainage basins, each administered by a corresponding Water Management District (WMD) under the supervisory authority of the Florida Department of Environmental Protection (FDEP). The governing statute is Chapter 373, Florida Statutes — the Florida Water Resources Act of 1972.

The state's watershed geography is shaped by three defining characteristics. First, Florida receives an average of 54 inches of rainfall per year — nearly double the U.S. national average of 30 inches — making it among the wettest states by precipitation volume, according to UF/IFAS Extension. Second, the terrain is exceptionally low-gradient, so surface water moves slowly across broad, shallow drainage areas. Third, the Floridan Aquifer system — a regionally extensive carbonate aquifer underlying virtually all of Florida — links groundwater recharge zones directly to surface water through thousands of springs, making groundwater and surface water functionally inseparable in most watersheds. For assessment and monitoring purposes, FDEP further subdivides all water resources into 6,727 Water Body Identification segments (WBIDs), as documented by the Florida Office of Economic and Demographic Research (EDR) in its 2023 Annual Assessment.

Before the Florida Water Resources Act of 1972, the state managed water through single-purpose districts organized around mosquito control, flood control, and irrigation — with no unified statewide framework. Facing rapid population growth in the late 1960s, state policymakers enacted Chapter 373, Florida Statutes, which replaced those fragmented arrangements with five regionally defined Water Management Districts aligned to major drainage basins. As documented by UF/IFAS EDIS Publication FE1043, the Act was modeled substantially on the Model Water Code, a scholarly framework that addressed surface water, groundwater, diffused surface water, and water pollution in an integrated manner.

The five WMDs established under that framework are the Northwest Florida Water Management District, the Suwannee River Water Management District, the St. Johns River Water Management District, the Southwest Florida Water Management District, and the South Florida Water Management District. Each district is governed by a board appointed by the Governor and carries four core mandates under FDEP supervision: water supply, water quality, flood protection and floodplain management, and natural systems protection. The Florida Public Service Commission documents that each WMD's authority includes issuing consumptive use permits, managing aquifer recharge areas, and overseeing surface water systems within its geographic boundaries.

FDEP operates on a rotating basin cycle, cycling through five basin groups over five years to conduct monitoring, water body assessments, Total Maximum Daily Load (TMDL) development, and nonpoint source management across all 29 watersheds, as described by UF/IFAS EDIS Publication SS568. This cycle drives both the listing of impaired water bodies and the development of Basin Management Action Plans (BMAPs) — legally enforceable restoration frameworks adopted by DEP secretarial order under Sections 403.067, 403.121, 403.141, and 403.161, Florida Statutes. Each WMD is additionally required to produce 20-year regional water supply plans, a mandate that directly shapes land use decisions and infrastructure investment statewide.

The 29 major watersheds are distributed across five regional basins that reflect distinct geographic and hydrological identities. The UF/IFAS EDIS Publication AE265 on Florida Watershed Regions provides basin-level characterizations for each.

The Northwest basin, administered by the Northwest Florida Water Management District, contains the largest number of rivers and streams in the state, including the Apalachicola-Chipola system (Watershed No. 4) and the Ochlockonee-St. Marks system (No. 5). More than 70% of the Northwest basin's area is classified as forested or forested wetland. The Suwannee River basin, overseen by the Suwannee River WMD, is the least-populated major basin in Florida. The Suwannee River (Watershed No. 6) originates in the Okefenokee Swamp in Georgia and flows south into the Gulf of Mexico; surface water quality is largely good across the basin, though specific sub-basins such as the Fenholloway River drainage carry impairments from industrial discharges. The Springs Coast watershed (No. 8) also falls within this basin and is defined by its dense concentration of first-magnitude springs.

The St. Johns River WMD covers northeast and east-central Florida, encompassing the Upper, Middle, and Lower St. Johns watersheds (including No. 16) as well as the Indian River Lagoon (No. 26) — one of the most species-diverse estuaries in North America. The Southwest Florida WMD administers a stretch of ecologically sensitive Gulf Coast estuaries, including Tampa Bay (No. 10), the Withlacoochee (No. 11), Charlotte Harbor (No. 15), and the Caloosahatchee (No. 18). The South Florida WMD covers 40% of Florida's population and 31% of the state's total land area, containing Lake Okeechobee (No. 25), the Kissimmee River (No. 20), the Everglades (No. 23), and Florida Bay — the southernmost reach of a water system draining approximately 18,000 square miles.

The FDEP's official Florida Watersheds Map enumerates all 29 watersheds by assigned number, providing the authoritative geographic reference for the state's watershed boundaries.

Florida's watershed water quality framework centers on the TMDL program, through which FDEP establishes the maximum amount of a given pollutant a water body can receive while still meeting water quality standards. Where a water body is listed as impaired, FDEP is required to develop a Basin Management Action Plan (BMAP) — a legally binding restoration framework that assigns pollutant-load reductions to permitted facilities, agricultural operations, and local governments through permit limits and Best Management Practices (BMPs). BMAPs are adopted by DEP secretarial order and are enforceable under §403.067(7)(d)1., Florida Statutes, with 20-year TMDL targets structured around 5-, 10-, and 15-year milestones, as documented in the Florida EDR 2024 Annual Assessment.

The projected cost of BMAP compliance between FY 2022-23 and FY 2039-40 is $11.6 billion — a figure that represents a near 10% increase over the previous EDR edition — with 53%, or approximately $6.1 billion, identified as a state responsibility, according to the Florida EDR 2023 Annual Assessment.

Springs are a particularly acute water quality concern. The Floridan Aquifer discharges base flows to rivers through thousands of springs concentrated in the Suwannee River and Springs Coast basins. A 2020 FDEP water quality assessment found that more than 75% of frequently monitored springs had nitrate-nitrogen concentrations exceeding the 0.35 mg/L threshold, as reported by UF/IFAS EDIS Publication FR440. Nitrate sources documented in the recharge zones include septic systems, wastewater treatment facilities, and agricultural fertilizers. In 2016, the Florida Legislature identified 30 Outstanding Florida Springs as Priority Focus Areas under the Florida Springs and Aquifer Protection Act (FSAPA), requiring FDEP to develop BMAPs for each impaired spring. The FDEP 2024 Statewide Annual Report on Water Quality, issued under Section 403.0675, Florida Statutes, documents current TMDL, BMAP, and minimum flow and minimum water level (MFL) status across all basins.

The South Florida watershed region contains the Everglades — approximately 3,480 square miles of subtropical wetland that the UF/IFAS EDIS watershed regions publication describes as the largest subtropical wetland in the United States. The South Florida Water Management District (SFWMD) identifies four primary watersheds within the Greater Everglades Ecosystem that form the core of its restoration work: the Kissimmee River watershed, Lake Okeechobee, the Caloosahatchee Estuary Basin, and the St. Lucie Estuary Basin. Together, the Kissimmee-to-Florida Bay corridor drains and distributes water across roughly 18,000 square miles.

The Comprehensive Everglades Restoration Plan (CERP), authorized by the Water Resources Development Act of 2000 (WRDA 2000), is documented as the single largest ecosystem restoration program in the United States. CERP operates as a federal-state partnership between the U.S. Army Corps of Engineers and the State of Florida. Separate from but complementary to CERP, the Kissimmee River Restoration Project — a 22-year construction effort to reverse mid-20th-century channelization of the river — was completed in 2021 with approximately $1.0 billion in federal expenditures, according to the Congressional Research Service (CRS IF11336).

Florida's history of large-scale wetland drainage, which began in the late 19th century as canals were cut across the peninsula to convert swampland for agriculture and residential development, frames the restoration imperative: the dominant management concern shifted across the 20th century from removing excess water to ensuring adequate supply and quality for a population that, in the South Florida region alone, represents 40% of the state's total residents.

In January 2023, Governor Ron DeSantis signed Executive Order 23-06, titled Achieving Even More Now for Florida's Environment, directing accelerated implementation of restoration projects and natural resource protection statewide, as documented by the South Florida Water Management District.

In July 2025, the State of Florida and the U.S. Department of the Army signed a landmark agreement specifically targeting acceleration of the Everglades Agricultural Area (EAA) Reservoir — a major CERP component intended to capture, store, and clean water flowing south from Lake Okeechobee into the Everglades system. The agreement was identified by SFWMD as a significant milestone in the multi-decade restoration effort.

The Florida EDR 2024 Annual Assessment documents that July 2023 legislation added enhanced provisions to BMAP enforcement and introduced water quality enhancement areas (WQEAs) through CS/CS/CS/HB 965 (2022), providing an additional compliance pathway for BMAP obligations in the Caloosahatchee and St. Lucie Estuary basins. FDEP's annual reporting obligation under Section 403.0675, Florida Statutes, produces the Statewide Annual Report on Water Quality, which documents TMDL attainment progress, active BMAPs, and MFL compliance across all 29 watersheds on an ongoing basis.

Florida's watershed governance intersects with several other state-level systems documented in the brief. The Floridan Aquifer recharge zones connect watershed land use directly to drinking water security: aquifer recharge areas are mapped and protected under Rule 62-330, Florida Administrative Code, and the same zones that supply springs also supply municipal and private drinking water wells across much of north and central Florida.

Florida's agriculture industry is a primary documented source of nitrate loading in aquifer recharge areas, particularly in the Suwannee River and Springs Coast basins, connecting watershed management directly to the regulation of farming practices. The phosphate mining industry, concentrated in the Peace River watershed within the Southwest Florida WMD, represents another documented intersection of watershed policy and industrial land use. Springs, simultaneously threatened by nitrate pollution and valued for recreation and tourism, connect the ecological health of the Suwannee and Springs Coast watersheds to the state's tourism economy.

In South Florida, the Everglades restoration program links watershed governance to federal infrastructure investment under WRDA 2000 and WRDA 2020, to the water rights of the Miccosukee Tribe and the Seminole Tribe, to the urban water supply of the Miami metropolitan area, and to the health of coastal fisheries in Florida Bay and Biscayne Bay. The Indian River Lagoon — Watershed No. 26, within the St. Johns River WMD — connects nutrient-driven seagrass die-off events to watershed governance and to the commercial and recreational fishing industries dependent on lagoon productivity. Across all 29 watersheds, the $11.6 billion projected BMAP compliance obligation represents a direct civic and fiscal connection between watershed science and the budgetary decisions of Florida's Legislature and its 67 county governments.