Water supply plan depends on lake

Lake Okeechobee is one of the water sources critical to supplying water for the growing population of the Lower East Coast under the South Florida Water Management District Lower East Coast (LEC) Water Supply Plan.

At their Nov. 8 meeting, the SFWMD Governing Board approved an update of the Lower East Coast Water Supply Plan, which ensures there will be enough drinking water for the more than 6 million residents of South Florida’s lower east coast region.

The LEC Water Supply Plan directly protects water sources in Palm Beach, Broward and Miami-Dade counties and parts of Monroe, Collier and Hendry counties for the next 20 years.

According to the plan, current water supply source options in the LEC Planning Area include surface water, groundwater (fresh and brackish), reclaimed water, and seawater. Surface water from canals, lakes, and water conservation areas, and fresh groundwater from the surficial aquifer system (SAS) are considered traditional water sources. Alternative water sources include brackish groundwater from the Floridan aquifer system (FAS), seawater, reclaimed water, and excess surface water and groundwater captured and stored in aquifer storage and recovery (ASR) wells, reservoirs, and other storage features. Use of alternative water supplies is an integral part of the current and future water supply strategy in the LEC Planning Area. Public water supply utilities within the LEC Planning Area primarily rely on fresh groundwater from the SAS, with limited use of the FAS and one utility using surface water.

Groundwater sources can meet 2040 public water supply demands; however, increases in fresh groundwater allocations are limited to comply with resource protection criteria, the plan states. Of the 54 public water supply utilities in the LEC Planning Area, nine will need to construct new projects to meet their projected 2040 demands, and six of those will need additional permit allocations. These new projects include expanded use of the FAS and use of the C-51 Reservoir, both of which are alternative water sources, or interconnections for bulk water from nearby utilities.

Approximately three-quarters of the total agricultural acreage in the LEC Planning qrea is in the Everglades Agricultural Area, which relies exclusively on surface water. There are two other agricultural areas in the LEC Planning Area that rely on fresh groundwater: southern Miami-Dade County and the eastern portion of Hendry County. In those areas, according to the report, groundwater sources can meet 2040 agriculture demands; however increases in fresh groundwater allocations are limited by resource protection criteria.

The future water use plan projects agriculture use will decrease by 4 percent, and the urban demand will increase by 26 percent by 2040. During years with normal rainfall, there is sufficient water supply. Drought years can bring water shortages.

“No one can predict whether Mother Nature will leave our district with a deluge of water or create a drought. That is important to remember when advocating for lower lake levels in Lake Okeechobee,” said SFWMD Governing Board Chairman and Miami-Dade County resident, Federico Fernandez. “The Lower East Coast Water Supply Plan considers Lake Okeechobee water essential to replenishing the region’s drinking water wellfields and ensuring their water supply.”

The Lower East Coast’s approximately 6 million residents, businesses, industries and agricultural operations use almost 1.7 billion gallons of water per day, according to SFWMD data. SFWMD updates regional water supply plans every five years. The plans identify water sources in relation to water demand over the next 20 years.

The update approved by the Governing Board estimates the LEC’s population will increase by about 26 percent by 2040, resulting in 7.5 million residents by 2040. Demand for water in the LEC is expected to increase to more than 2 billion gallons per day.

According to a SFWMD press release, efforts by SFWMD and utilities to promote water reuse and conservation have helped control the demand for water amid an ever-increasing population.

The plan update also anticipates the potential impact of sea level rise on water supply by 2040. The plan specifically takes into account the potential threat of salt water intruding farther into underground freshwater wellfields that are used to supply drinking water to residents. SFWMD works with the U.S. Geological Survey to map the underground saltwater front every five years. The next SFWMD saltwater intrusion mapping will be conducted in 2019.

Maintaining adequate levels of water in Lake Okeechobee also helps combat sea level rise and encroachment of saltwater intrusion because it allows SFWMD to move water into canals to recharge underground aquifers during the dry season, according to the report. If levels in the lake were kept too low during dry periods, SFWMD would be unable to supply enough fresh water to conservation areas and canals to keep the underground saltwater front from moving farther inland. This scenario could potentially endanger the drinking water supply of millions of residents.

Publisher Katrina Elsken can be reached at kelsken@newszap.com

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