St. Johns River Water Management District • P.O. Box 1429 • Palatka, FL 32178-1429

Phone: (386) 329-4500 (Palatka headquarters switchboard) • On the Internet: http://sjr.state.fl.us

6/00

The Guana Marsh Renovation Project

History

The Guana Basin is an 8,300-acre area in the

northeast corner of St. Johns County and the

southeast corner of Duval County.

Historically, the 15-mile-long narrow marsh

drained gradually into the Guana River, which

flows southward into the Tolomato River. 

The Guana River is a brackish (slightly salty)

estuary. The system was altered beginning in

the late 1700s by structures that restricted

marsh flow and allowed the upper part of the

river to become predominantly freshwater.

The freshwater flushed salt out of the soil to

support agricultural efforts, including rice and

corn cultivation.

After World War II, development began in the

upper basin and the first causeways — Solano

Road, Corona Road, Stockton Road and

Mickler Crossing — were constructed roughly

perpendicular to the path of the basin.

The problems

Over time, the Guana Marsh basin has been

dammed and crossed by causeways for 

agricultural and residential development.

With construction of the Guana Dam in 1961,

natural tide and salinity cycles for the entire

Guana Marsh watershed were disrupted.

Loss of saltwater exchange and an increase in

nutrients due to the use of fertilizers have led

to the heavy growth of cattails and willows,

which have clogged the historic water channel.

Vegetation blocking the channel and flow

structures caused increasingly more severe,

frequent and longer-lasting occurrences of

flooding in the Ponte Vedra residential 

neighborhoods within the Guana Basin. 

The gradual elevation of water tables in the

basin has resulted in widespread septic tank

failures and saturated septic drainfields. Water

FAST FACT

The project area

spans 8,300 acres

in Duval and 

St. Johns counties.

quality has gradually decreased as the amount of

bacteria and nutrients in the system have increased.

What has been done

In 1996, St. Johns County, along with the Ponte

Vedra Municipal Service District and the St. Johns

River Water Management District, funded the

development of a Guana Basin Master Plan.

The plan calls for a series of marsh improvements,

including alleviating the frequency and duration

of flooding, maintaining the habitat and channel

through the Guana Marsh and ensuring water

quality is maintained throughout the Guana

Marsh watershed.

In 1997 and 1998, the Florida Legislature 

appropriated a total of $1.23 million to conduct a

watershed study, develop plans, obtain 

permits and construct structures to improve

water quality and water flow.

Working on solutions

Construction of water quality and flow structure

improvements were completed in spring 2000.

Work included:

● Re-establishing the historic channel through

harvesting of nuisance aquatic plants 

(cattails and willows)

● Replacement of inadequate or failing flow

structures with box culverts at Corona Road

and in the Seawalk and Sawgrass entrance

causeways

● Construction of a water control weir at

Corona Road to provide water level 

control and to provide storage for water

quality treatment

● Installation of water level control structures

at Mickler Road and the Sawgrass resort

entrance causeway to prevent overdrainage

of Guana Marsh

● Construction of structural flow improvements

on Sawgrass Golf Course holes four and

five, funded by the golf course

Continued on back
St. Johns River Water Management District • P.O. Box 1429 • Palatka, FL 32178-1429

Phone: (386) 329-4500 (Palatka headquarters switchboard) • On the Internet: http://sjr.state.fl.us

6/00

Maintaining Outstanding 

Florida Waters

A work group of representatives from St. Johns County, 

the District and the Florida Fish and Wildlife Conservation

Commission (formerly the Florida Game and Fresh Water

Fish Commission) has been established to address water

quality and flooding issues and ongoing monitoring,

maintenance and management needs for this 

state-designated Outstanding Florida Water.

A plan to monitor, evaluate, enhance and maintain water

quality is being developed. The plan will be included in the

project permit and implemented to reduce nutrients in the

system and improve discharges from the basin into the

Guana River Wildlife Management Area. The area has been

designated by the state as an Outstanding Florida Water.

Other ongoing activities in the area include:

● Supporting efforts to remove septic effluent from affected

waters by replacing them with a central sewer system

● Maintaining the historic channel through 

continued harvesting of nuisance aquatic plants

● Supporting local efforts to reduce the levels

of fertilizer entering the system

● Supporting local efforts to reduce the levels of

fertilizer entering the system

● Establishing a watershed education program

through the Florida Yards, Neighborhoods and

Ponds program

● Continuing water quality monitoring activities

● Development of a proposed vegetation 

collection area to facilitate removal of 

nutrients through the harvesting of aquatic

plants in the Guana Marsh

● Working with golf courses and landscape 

professionals to develop and implement 

best management practices for existing and

new developments