Water bodies, watersheds and storm water

Keystone Heights area lakes

Keystone Heights is a rural town located on a high sand ridge in southwestern Clay County. One of the area’s most distinguishing features is its numerous lakes, which were created by the collapse of a layer of limestone that lies beneath the lakes’ sandy bottoms and often a layer of clay. Called karst terrain, this geologic feature of the Keystone Heights area is natural.

In recent years, Keystone Heights’ lakes have been severely impacted by prolonged drought conditions, as are many lakes across Florida.

Low water levels in Keystone Heights area lakes are largely the result of reduced rainfall over many years — even decades — that have been worsened by the area’s geology.  In Keystone, many lake bottoms are made of sandy, permeable soils that allow significant downward leakage of water.

Regional groundwater pumping is also a contributing factor to the area’s low groundwater levels, which in turn can affect surface water levels in the area’s leaky lakes.

The Keystone Heights lakes receive water by directly capturing precipitation, from stormwater runoff, by groundwater seepage from surficial aquifer systems recharged by rainfall percolation, and from streams fed by seepage from groundwater and flow from other lakes. Rainfall is the only source of water for all of these flow paths to lakes.

Blue Pond and lakes Lowry, Magnolia, Brooklyn and Geneva are interconnected by streams, known as Alligator Creek. The lakes in the Alligator Creek chain all leak downward into the Floridan aquifer system.

When Alligator Creek ceases to flow into Lake Brooklyn, the lake’s level rapidly falls. Lake Brooklyn exhibits large fluctuations in water levels as water drains to the aquifer during dry periods and as water is replenished faster than it drains during wet periods.

Accomplishments

The St. Johns River Water Management District has been involved in numerous efforts to bring greater understanding and has dedicated significant staff and financial resources to the Keystone Heights’ lakes issue, including participation in at least nine regional studies.

The District’s recent contributions to the area include:

These three pools of water combine to make one large lake (Lake Brooklyn) during times of higher water levels. This photo was taken in July 2002 at the height of a drought.

This photo of Lake Brooklyn from 2005 shows how the lake had risen due to increased rainfall in the area.

• Facilitating an inclusive stakeholder process to develop prevention/recovery strategies for Lake Brooklyn and Lake Geneva in Clay County and Cowpen Lake and Grandin Lake in Putnam County, where MFLs are currently not being met or are projected not to be met within 20 years. The District and stakeholders are working collaboratively to develop long-term comprehensive strategies to achieve the MFLs.
• Pilot testing a broader initiative that would seek  to protect and maintain regional aquifer levels by capturing significant quantities of alternative sources of water to recharge the Upper Floridan aquifer at strategic locations. Replenishment of the Upper Floridan aquifer would benefit lakes, springs and wetlands and contribute to sustainable water supply for the region. The initiative would be a key component to achieving MFLs in water bodies that are currently not meeting their MFLs or are projected to not meet their MFLs within 20 years.
• Partnering with the Suwannee River Water Management District, the Florida  Department of Environmental Protection, north Florida local governments and other stakeholders to ensure sustainable water supplies and protection of north Florida’s waterways and natural systems. Highlights of the partnership include developing a shared tool to predict and assess water resource impacts and studying the regional groundwater decline in north Florida. The partners also are committed to developing a regional water supply plan for north Florida that encompasses counties in both water management districts.

Water levels in Lake Brooklyn were above average in April 1996.

This photo from 2009 shows a healthy inflow of water to Lake Brooklyn from Alligator Creek.

Past District contributions have included:

• Providing funds for an independent consultant to investigate the causes of low lake levels in the Keystone Heights lakes. The consultant completed the study in 2002 and generated a report offering a broad range of ideas to increase water levels in Lake Brooklyn, primarily by increasing streamfall when rainfall does occur. The report identified ideas that were technologically feasible, but the ideas were not screened based on economic or environmental feasibility.
• Cooperatively funding water resource investigations by the U.S. Geological Survey, as well as surface geophysical investigations
• Coordinating and providing cost-share funds to initiate a project, in coordination with the Suwannee River Water Management District and DuPont, that recaptures a portion of DuPont’s Florida mine surface discharge and directs it to the Keystone Heights lakes watershed
• Monitoring surface and groundwater levels
• Requiring local mining operations to reduce their dependence on groundwater supplies through the District’s consumptive use permitting process
• Permitting local projects to improve flow to the Alligator Creek system

Updated on 3-14-2012