Nassau County to review bids for watershed master plans covering two river basins

Nassau County will hold a public evaluation meeting October 20 to review proposals for comprehensive watershed master plans covering the Nassau River and St. Mary's River basins, the county announced. The 2 p. m. session at the James Page Government Complex in Yulee marks a key step in a planning effort that will shape how the fast-growing county manages stormwater, flooding, and water quality across much of its western and northern territory.

The solicitation, designated NC26-015-RFP, seeks consulting teams to map drainage patterns, identify flood-prone areas, and recommend infrastructure investments across the two watersheds. Both basins drain large swaths of Nassau County's development corridors, including Wildlight, the SR 200 and A1A intersection area in Yulee, and rural communities such as Callahan and Hilliard that are seeing new residential subdivisions as growth spreads inland from the coast.

What's happening

Nassau County issued a request for proposals for watershed master plans covering the Nassau River Basin and the St. Mary's River Basin. The evaluation meeting is scheduled for October 20, 2026, at 2:00 p. m. in the OMB Conference Room at the James Page Government Complex, 96135 Nassau Place, Yulee.

The procurement is identified as NC26-015-RFP. The meeting is open to the public, and the Board of County Commissioners will review submissions from consultants vying to produce the master plans. No dollar amount for the contract, timeline for completion, or number of proposals received was disclosed in the notice.

A watershed master plan typically inventories existing drainage infrastructure—pipes, ditches, retention ponds, and natural waterways—models how stormwater moves during rain events of varying intensity, pinpoints locations where flooding occurs or is likely to worsen, and prioritizes capital projects to expand capacity or reduce pollution. In Florida, such plans also address nutrient loading into rivers and estuaries, a concern for water bodies like the Nassau River that flow into sensitive coastal marshes.

The Nassau River originates in the Okefenokee Swamp region and flows south through western Nassau County before emptying into the Nassau Sound near Amelia Island. The St. Mary's River forms much of Nassau County's northern boundary with Georgia, draining the county's northwestern corner and feeding into Cumberland Sound. Both watersheds include significant wetlands, floodplains, and tributaries that are under increasing pressure from land conversion.

Why watershed planning matters now for Nassau County

Nassau County is one of the fastest-growing counties in Northeast Florida, with new subdivisions, distribution centers, and commercial development clustering along the SR 200 corridor in Yulee and pushing west toward Callahan. Wildlight, the Raydient-developed master-planned community just off I-95, has already delivered thousands of homes and continues to build out; other large residential projects are in the pipeline throughout the county's western half.

That growth translates directly into more rooftops, roads, and paved surfaces—impervious cover that prevents rain from soaking into the ground and instead sends it racing into ditches, streams, and eventually the Nassau and St. Mary's rivers. Without coordinated planning, the result is predictable: more frequent and severe flooding in existing neighborhoods downstream, higher pollutant loads entering the rivers, and costlier emergency fixes when pipes and ponds are overwhelmed.

Watershed master plans are the tool counties use to get ahead of that curve. By modeling future conditions—how much stormwater a fully built-out area will generate—the plans allow engineers to size detention ponds, design pipe networks, and reserve land for regional stormwater facilities before development locks in patterns that are expensive to retrofit. They also guide the county's capital budget, showing which drainage projects deliver the most flood-risk reduction per dollar spent.

For residents in low-lying areas near tributaries of the Nassau River—such as neighborhoods around Lofton Creek or Alligator Creek—the master plan could identify projects that reduce the risk of yard flooding or road closures during heavy summer storms. For homeowners in newer subdivisions, the plan helps ensure that upstream development doesn't send additional runoff into their community's ponds, causing them to overflow.

Environmental and regulatory stakes

Both the Nassau River and the St. Mary's River are tidally influenced in their lower reaches and support recreational fisheries, oyster beds, and marsh ecosystems that are sensitive to nutrient pollution and sediment. Stormwater runoff carries fertilizers, pet waste, and other pollutants that can fuel algae blooms and degrade water quality, a problem that has plagued Florida rivers and estuaries statewide.

Nassau County operates under the Florida Department of Environmental Protection's National Pollutant Discharge Elimination System (NPDES) stormwater permit, which requires the county to reduce pollutant loading and demonstrate that new development does not increase downstream flooding. Watershed master plans are a common component of NPDES compliance, providing the technical foundation for the county's stormwater ordinance, development review, and infrastructure investments.

The plans will also inform permit applications to the St. Johns River Water Management District, which has jurisdiction over surface-water management systems in Nassau County. Large regional stormwater projects—such as detention basins that serve multiple subdivisions or stream-restoration work—typically require SJRWMD environmental resource permits that assess wetland impacts, water-quality treatment, and flood-storage capacity. A watershed master plan gives the county a blueprint to pursue those permits strategically rather than on a parcel-by-parcel basis.

Environmentally, the open question is whether the master plans will recommend low-impact development techniques—pervious pavement, rain gardens, preserved wetland buffers—that slow runoff at its source, or whether the county will rely primarily on large end-of-pipe detention ponds. The scope of work in the RFP, not disclosed in this brief notice, will determine how much emphasis consultants place on green infrastructure and habitat protection versus conventional pipe-and-pond engineering.

Infrastructure costs and who pays

Watershed master plans do not build anything by themselves; they produce a prioritized list of projects that the county must then fund. In Nassau County, stormwater infrastructure is typically paid for through a mix of ad valorem taxes, stormwater utility fees (if the county has adopted such a fee—many Florida counties now charge a monthly stormwater fee on utility bills based on property size), impact fees charged to new development, and grants from state and federal agencies.

The total price tag for implementing a watershed master plan can run into the tens of millions of dollars over a decade or more, depending on how much capacity needs to be added. For example, a regional stormwater pond serving several hundred acres of development might cost $2 million to $5 million to design, permit, acquire land, and construct. Pipe upgrades in established neighborhoods with undersized drainage can run into the hundreds of thousands of dollars per mile.

For property owners, the question is whether the county will finance these improvements through higher taxes, a new or increased stormwater fee, or by requiring developers to build oversized regional facilities as a condition of approval. The evaluation meeting and eventual plan adoption will not answer that question directly, but the scale and cost of the recommended projects will frame the budget and policy debates to come.

New development in the watersheds will likely face closer scrutiny once the master plans are complete. If a plan shows that a particular subbasin is already at or near capacity, the county may require developers to provide additional stormwater storage on-site, fund off-site improvements, or delay projects until regional infrastructure is in place. This is a common outcome of watershed planning in rapidly growing Florida counties and can affect the pace and density of new subdivisions.

What happens next

The evaluation meeting on October 20 is the step at which county staff and the selection committee review the technical proposals, interview shortlisted consultants if the procurement process includes interviews, and score the submissions. The County Commission will ultimately award the contract, likely at a subsequent regular meeting, though no vote date was announced in the notice.

Once a consultant is selected and under contract, the master-planning process typically takes 12 to 24 months, depending on the size of the study area and the amount of fieldwork, modeling, and public input involved. The consultant will collect existing data on topography, soils, land use, and drainage infrastructure; build a hydrologic and hydraulic model of the watersheds; run scenarios for current conditions, future development, and storm events of different sizes; and draft recommendations.

Public workshops are a standard part of the process, giving residents a chance to point out local flooding hot spots and comment on draft recommendations before the plan is finalized. Those workshops have not yet been scheduled, but they would likely occur in mid-to-late 2027 if the contract is awarded promptly.

The final master plans will be presented to the Board of County Commissioners for adoption. Once adopted, the plans become reference documents for development review, capital budgeting, and grant applications. They are typically updated every five to ten years as land use and hydrology change.

The October 20 evaluation meeting is open to the public, but it is primarily a technical review session rather than a public-comment hearing. Residents who want to observe the procurement process or understand which firms are competing for the work are welcome to attend. The meeting will be held in the OMB Conference Room at the James Page Government Complex, 96135 Nassau Place in Yulee.

A planning tool for a county in transition

Nassau County's decision to pursue watershed master plans for its two largest river basins reflects the infrastructure catch-up that accompanies rapid growth. For decades, much of western Nassau County was rural, with septic systems, dirt roads, and minimal stormwater infrastructure. Now, as the region absorbs spillover from Jacksonville and attracts residents priced out of St. Johns County, the county is building the planning and engineering backbone that urban and suburban areas require.

Across Northeast Florida, similar watershed studies are underway or recently completed in St. Johns County, Clay County, and parts of Duval County, all driven by the same dynamic: more rooftops, more pavement, more runoff, and higher expectations from residents that roads won't flood and rivers won't degrade. The Nassau River and St. Mary's River master plans will help determine whether Nassau County manages that growth proactively or struggles with drainage crises and water-quality problems that are far more expensive to fix after the fact.