Beach waters feeling Lake O releases
The salinity level, living organisms (such as plant life, marine animals) and possibly even human respiratory health are all feeling the affects of the recent prolonged Lake Okeechobee releases into the Caloosahatchee River.
Regulating flows from lake and water sheds to river have become a delicate balancing act between scientists and engineers, between protecting estuaries and the overflow of the lake.
Town of Fort Myers Beach Environmental Sciences Coordinator Keith Laakkonen has been monitoring the situation. While releases are year round, the releases have been larger and more frequent during this time of year due to heavy seasonal rains.
“There has been just so much rainfall and, with the release from both the lake and its water sheds, we have had high flows up to 10,000 cubic feet per second,” he said.
Laakkonen stated that much scientific research shows that anything higher than 4,500 cu ft/s is harmful to the estuaries.
“It can affect the estuary from driving down the salinity to causing death to oysters, sea crabs and sea grass. It really can upset the delicate fresh/salt water balance the estuaries need,” he said. “It’s pretty much 100 percent fresh all the way down to the Iona area on the river.”
The fresh water releases have affected northern parts of Estero Bay. Laakkonen stated as water comes down the Caloosahatchee, it banks a left and can actually go back under Matanzas Pass and mix far back as Hell Peckney Bay.
“That whole Matanzas Pass area around San Carlos Island is much fresher than it would be naturally at this time of year due to the releases from the lake,” he said.
Laakkonen is on weekly conference calls with local scientists, wildlife refuge officials, state senators’ office personnel and the Army Corps of Engineers. Those discussions involve updated local estuary conditions, rainfall conditions and weekly and seasonal weather forecasts. Decisions are then made.
“On those phone calls, we do make recommendations and requests. We have been requesting them to use all available storage to reduce these high flows,” said Laakkonen. “The water coming out of the lake is very dark colored, which prevents light from being transmitted all the way down to the bottom. That also impacts sea grasses.”
If the water is too fresh, fish and other organisms relocate to outer waters.
“These organisms have to move to areas where they can manage salinity balances,” he said. “Some may move south, further offshore or seek other parts of the estuary that are not so impacted. When you are losing a big part of your living habitat, you know you are having an impact to the estuary.”
Laakkonen said the corps of engineers are concerned about the integrity of the dike around Lake O. Watershed storage space is limited, so some of that has been released as well.
“All that water is being pumped out pretty rapidly. So we are getting very high watershed rain flows and very high lake rain flows,” he said. “The problem is that there is no other storage areas to put water during high rainfall events. We’ve been waiting on the T43 reservoir (part of Everglades restoration project) in the Caloosahatchee watershed for many, many years. If we had some other things in place to hold some of this water back, we would be able to keep some reserve for later in the year when it gets drier.”
The brown, brackish color to the bay waters and along the beachfront is a result of the release action. The flows have also brought an abundance of nutrients, which may cause algae blooms. There have been some lingering threats of red drift algae off of Bowditch Point.
“Those are algae that have probably been growing in and around San Carlos Bay and are very responsive to high nutrients,” said Laakkonen. “What happens is this algae grows rapidly and, as it grows, it’ll break off and drift to shore. It’ll take a while fro theses nutrients to get out of the system.”
Laakkonen said the Town is monitoring the algae situation very closely. The action appeared to be only on the northern end of the island, but not consistent enough to warrant alarm. Action will be taken if and when the algae moves around to the beachfront.
“The environment is the basis of our economy,” he said. “If the estuaries are taking this big of a hit, it has the potential to affect our economy.
Another problem arises when officials from the agricultural areas, specifically the sugar cane fields on the east side of the lake, are back-pumping water into the lake due to flooding issues that have occurred during the heavy rain.
“Everything that could possible go wrong for the lake and the estuary is,” said Laakkonen.
Laakkonen said the scientists in Southwest Florida requested more water in the middle of the spring. Natural sea grass beds were recovering and fresh water was needed to continue the recovery process, but the salinity increased with a reduction of flows.
“At that time, they didn’t want to give us as much then because they were afraid they wouldn’t have enough. Now they have too much, and they are giving us everything at once,” he said. “There is so much water coming down that it is blowing out the sea grass in San Carlos Bay and around Ding Darling National Wildlife Refuge. That’s the problem with these estuaries. It becomes a very flashy system. It goes from too salty to too fresh. These are major swings that are difficult for the environment to adapt to.”
The army corps claims there is very little they can do right now, says Laakkonen.
“One of the things they can do is try to find more storage capacity,” he said. “You need places to hold back and bank some of this water so that we don’t get these huge fresh water slugs. We are keeping our fingers crossed. We need some drier conditions. Rainfall over the lake and water sheds especially has been a little heavy and intense. That’s driving the whole system right now.”
Why the lake releases
Laakkonen offered a scientific explanation as to why water is released from lake to river.
“The lake is managed at certain levels at certain times of the year for water supply and also maintaining ecology of the lake and natural systems. If the water gets too high, then there is concern that it could threaten the integrity of the dike around the lake. If that happens, there are concerns that there could be a breach and possibly a flood to some neighboring areas.
Laakkonen said the reason dates back to two strong Florida hurricanes from the 1920s era caused extensive flooding that killed a lot of people around the lake.
“The dike was built in response to that. It has not been reinforced much since it had been built. So, you have a very old levee system and concern that if the water gets too high, the lake could fail and we could have another catastrophic flooding.”