Everglades water plan should help with Shark Valley flooding, water flow in dry season

Despite Everglades National Park experiencing below-average rainfall earlier this year during the dry season, Florida Bay is thriving with freshwater.

Freshwater helps combat the water’s hypersalinity, caused by sea level rise, which has been a problem in the Everglades ecosystem, said Antonia Florio, a science communications liaison for the National Park Service.

Part of the reason for the high-water mark can be linked to November’s rainfall levels, which were almost six times the norm, due to Tropical Storm Eta hitting then, according to the South Florida Water Management District. The November rains boosted the water levels from December to March, when the park’s rainfall was as low as 16% of the typical downpour in January.

New Everglades water plan helping with water flow

Florio attributes part of the success, however, to something besides rainfall: the park’s Combined Operational Plan, which took effect last August. The new water plan allows managers to consider the entire Everglades ecosystem while deciding when and where to send water through the Everglades region — from Lake Okeechobee, to the various water reservoirs and ultimately, to the park.

One benefit is that water flows now through the park during the dry season from December to May.

“It wouldn’t have happened without all that rainfall,” Florio said. “But it definitely helps that there are water management practices in place to handle that water now.”

The water plan should help stabilize the health of the Florida Bay estuary in coming years. Rather than contending with drastically contrasting water levels, park managers will be able to preserve freshwater accumulated during the wet season and deliver it to the park during the dry season.

Try to prevent flooding in Shark Valley

Michelle Collier, also a science communications liaison with the National Park Service, said the plan should work in conjunction with the Central Everglades Planning Project to prevent Shark Valley from flooding during normal wet seasons — although the unpredictable rainfall from tropical storms and hurricanes could lead to flooding anywhere. Last year, November’s heavy rainfall led to a two-month closure of Shark Valley despite the new water plan.

The idea, said Collier, is that water will be sent to one of the park’s deep, historic flow paths, Shark River Slough. Since they are deeper, sloughs can serve as a channel for a lot of water. And once it’s in the park, the water flows gradually and naturally into the bay and other estuaries along the Gulf of Mexico.

Collier said the water plan was made possible by new infrastructure put in place as a part of the larger Comprehensive Everglades Restoration Plan, including the elevation of Tamiami Trail. The district also created the Tamiami Trail Flow Formula, which is part of the Combined Operational Plan.

The formula allows park managers to consider the environmental conditions of the present day — such as water levels in Water Conservation Area 3, a water source just north of the park — before deciding how and when to move water under the Trail. The process is geared toward restoring the Everglades to its original, natural conditions.

The Tamiami Trail Flow Formula was used for the first time in March, Collier said.

“We’re moving to a place where we’re taking the environment of the Everglades into account,” she said. “Instead of only focusing on people, now the environment is going to have a say in where water goes.”

But these changes in water management benefit residents, too, said Collier.

“Restoring the water flow is good for South Florida beyond making the Everglades a healthy place,” she said. “It will help slow sea level rise, and it will help slow saltwater intrusion into our drinking water.”

This story was originally published June 2, 2021 at 5:35 PM.