Lake Okeechobee is rising — why can’t they send the water south?

When the sun rose on Monday morning, we could see Hurricane Irma’s immediate damage — homes damaged or destroyed, roads flooded, massive trees toppled, power lines down. But the hurricane’s aftermath continues to threaten South Florida as the water left by the storm drains south into Lake Okeechobee.

Before the storm, the lake was around 13.5 ft. above sea level. Water managers try to keep the Big O between 12.5 ft and 15.5 ft., which is considered the optimal range for the lake’s ecology and the safety of the Herbert Hoover Dike, a 143-mile earthen berm that surrounds Lake Okeechobee.

Less than a week after the hurricane, the lake neared 15 ft. as the rapid inflow of water from the north rushed down the Kissimmee River.

Water managers expect the lake  to rise to 17 ft.

The highest lake level ever recorded was 18.77 ft. Above that level, the dike has not been tested.

In the past, when the lake has gone above 17 ft., there have been places where the water made small holes in the dike. Clear flows go through the dike, and can be beneficial in relieving water pressure. Muddy flows means the water is carrying away part of the dike, making the holes larger. Bubble ups  push water under the dike.

U.S. Army Corps of Engineers inspectors examined the dike after the storm, and will continue inspections.

The Corps of Engineers has done a lot of work on the dike since the last time the lake was that high. They concentrated the work on the areas most at risk on the south end. The dike is in better shape now than it was when the 18.77 ft. was recorded.

On the north end of the lake, the land elevations are higher. On the north end, the only danger is during a hurricane, when winds can push the water against the dike. On the south end, land elevations are lower; in some areas just 12 ft. above sea level. If there were a breach on the south end, flooding could be catastrophic not only for those who live in the shadow of the Herbert Hoover Dike, but also for everything and everyone one south of Lake Okeechobee.

Why can’t they restore the natural flow?

The current flow into and out of Lake Okeechobee is anything but natural.

First, the water is coming in too fast. Nature designed the system to flood and then slowly drain off as it sheet flowed south. The people built developments, buildings with roofs the rain runs off; drainage ditches to move water away from areas humans want dry; roads and parking lots that prevent water from soaking into the soil.

The channelized Kissimmee River collects that water and it rushes south to Lake Okeechobee.

When the big lake was diked, the original footprint was reduced in size by about one-third. There’s more water coming in and less lake to hold it.

In addition, instead of the water overflowing the lake at the southern end and sheet flowing down through the Everglades to Florida Bay, the water now leaves the lake through culverts and canals.

Due to the man-made changes, water can flow into the lake six times faster than it can be drained with all of the flood gates open and pumps running at full blast. Right now, most of the gates can’t be opened because the areas west and south of the lake were already flooded by direct rainfall. South of the lake, the Everglades Agricultural Area was flooded by Hurricane Irma. South of the EAA, the water conservation areas and the flow equalization basin were already flooded by wet season rainfall even before the hurricane hit. West of the lake, the Caloosahatchee River basin was flooded by Hurricane Irma.

Until that runoff clears the system, no water from the lake can flow in those directions.

That leaves flow east through the Port Mayaca lock into the C-44 canal. Until just before the storm, water was flowing the other direction through  that lock. More than 25 billion gallons of water from the St. Lucie basin flowed INTO the lake this summer. That basin will be getting all of that water back now, and likely more.

What about Florida Bay?

According to the Corps of Engineers, they can’t send water any faster to Florida Bay right now. Flows to Florida Bay are at capacity. There is plenty of water to send. It’s already south of the lake. Getting the lake water past the Everglades Agricultural Area is not the problem.

The problem is three-fold:

• Before water can be sent to the Southern Everglades, it must, by law, be cleaned to less than 10 parts per billion phosphorus. (Rain water can be up to 8 ppb.)

Water going into the lake is many times that level. On the five year average (2012-2016) water from the upper Kissimmee is about 73 ppb; lower Kissimmee, 157 ppb; Lake Istokpoga, 84 ppb; Indian Prairie, 231 ppb.; Fisheating Creek, 164 ppb.; Taylor Creek/Nubbin Slough, 446 ppb.

In 1986, the Florida Department of Environmental Protection set the target level for the lake at 40 ppb phosphorus. The lake averaged around 125-130 ppb this summer according to SFMWD records.

The lake’s marshes clean some of the phosphorus out of the water. But when the lake gets over 16 ft., the marshes around the edges are drowned and cannot function as a nutrient filter.  Per FDEP, there is no way to clean up the lake and address the legacy phosphorus in the lake sediment until we find a way to clean up the water before it goes into the lake.

While farms and ranches have been held to stricter standards and have implemented strategies to reduce nutrients in runoff, no such standards have been set for urban areas.

With the nutrient-rich water going into the lake, and strict rules for water going into the Everglades, currently the water must be cleaned up after it leaves the lake and before it enters the Everglades. A series of marshes south of the EAA clean the nutrients out of the water.

• Even when the water is clean and available to send south, it doesn’t flow freely. The Tamiami Trail – a series of roadways from Tampa to Miami – acts as a dam to prevent the natural flow of water. When the roads were first built back in the 1920s, they just closed them in the rainy season and let the water flow over the road. But over the years the roadway was built up to accommodate heavier vehicles, heavier traffic and the political pressure from developers. Now the raised roadway acts as a dam. The Corps of Engineers has estimated 10 miles of raised bridging are needed to help restore flow of freshwater to Florida Bay. One mile was completed in 2013. Another 2,5 miles of raised roadway are under construction.

• Even if the SFWMD and the Corps could move clean water south of the Tamiami Trail, the U.S. Fish and Wildlife Service won’t always let them because it would flood the nesting grounds of the Cape Sable Sea Sparrow. The Cape Sable Sea Sparrow as not originally  native to that area. The sparrows nest in marl prairie. The area south of the Tamiami Trail was originally much wetter than it is now. But after the roadway blocked the flow, the area dried out and the endangered birds moved in. Ironically, the efforts to protected one endangered bird species are threatening other endangered species in the Everglades and in Florida Bay.

Why haven’t the Corps of Engineers and SFWMD done something to fix these problems?

They do have a plan. The Comprehensive Everglades Restoration Plan (CERP) was developed in 2000. It was originally estimated that it would take 30 years to complete, with a 50/50 cost share between the State of Florida and the federal government. But in the first 16 years, less than 20 percent of the funding needed for CERP was appropriated. With sufficient funding, half of the projects should have been completed by now. CERP falls further and further behind schedule because of the funding shortfall. Congress approves the projects – but approval is not appropriation.

Is there any way reduce the lake level?

The most effective immediate solution would be sunshine. The lake’s massive surface means that on a sunny, cloudless day, the lake can lose more water through evapotranspiration than the water managers can let out using all of the gates and pumps at the maximum levels.

With three named storms on the National Hurricane Center radar, Floridians should be concerned about the rising lake level. I just hope they don’t forget about it when storm season is over. Perhaps then we’ll find the political will to actually fund the CERP projects.

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