Lake Okeechobee and Watershed
Lake Okeechobee and Watershed
I have had ample opportunity to study the significant problems of massive phosphorus deposition in the Okeechobee watershed and lake while preparing for my speech given at IFAS on November 28th.
The amount of information that Dr. Paul Gray assembled was impressive. Dr. Karl Havens, who left the SFWMD to become Chair and Professor of UF/IFAS Department of Fisheries & Aquatic Sciences, is also an expert on the lake and its watershed. He contributed to the speech and was a constant companion while I was on the campus. We talked Okeechobee problems without halt. My conclusions have been peer reviewed by them and represent a consensus view as to what the Foundation and the people of central and south Florida can expect in the future.
Lake Okeechobee is significantly polluted by massive amounts of phosphorus that continues to flow from all sources: tributaries, canal return flows and back pumping.
There must be a substantial reduction in the amount of phosphorus entering Lake Okeechobee. This will be time consuming and vexing. It may take many years to achieve, but the survival of the ecosystem literally depends on dramatically reducing phosphorus. Millions of tons of phosphorus have been deposited in the watershed during recent decades, to such a degree that much of the soils, canals, wetlands and natural tributaries now are saturated with phosphorus and large quantities regularly enter the lake.
There is a strong link between the damage that excess phosphorus causes in the lake and how water levels in the lake are regulated. Lower water levels greatly reduce the phosphorus-related impacts.
Although the muck bottom sediments are rich in phosphorus, they can largely be contained out in the deeper region of the lake if maximum lake levels are held below 15 feet mean sea level.
Furthermore, with a water level regime fluctuating between 12 and 15 feet, the south and west shoreline areas of the lake can develop healthy marsh communities that effectively clean the water of phosphorus and provide excellent habitat for the lake’s fishery. It was the deadly combination of high water and water polluted by massive amounts of phosphorus that has brought the once clear and biologically diverse lake marsh areas to near ecological collapse, especially in recent years.
Hurricanes, tropical storms and significant nor’easters will stir up the bottom sediments sufficiently to create very high phosphorus levels, however impacts can be reduced and recovery time hastened if the lake contains a healthy shoreline plant community. A healthy marsh community not only is important for water quality and fisheries – it also supports wading birds, migratory water fowl and the Federally-endangered Everglades Snail Kite. All of these ecosystem services are jeopardized by the dangerous combination of high water and excessive levels of phosphorus.
Major problems:
· We cannot expect the water being sent south from Lake Okeechobee to the Everglades STA’s to have lower phosphorus content for many years, or perhaps even decades, given the lack of significant reductions in phosphorus loads to the lake over recent decades. In fact following this drought, a combination of a ‘normal’ rainy season and a hurricane(s) will dramatically increase the amount of phosphorus flowing into the lake regardless of upstream treatment facilities or reduction in phosphorus usage due to the accumulated amount of phosphorus in the system.
· The STA systems may be showing signs of saturation by phosphorus, and if this occurs, it is unclear how they can continue to perform their intended function of phosphorus removal to meet legally-mandated goals. It is not clear whether mechanical removal of plants and muck from the STA’s will reinvigorate their ability to remove phosphorus to meet agreed upon federal-state compliance figures.
Five actions must occur:
· Reduce the amount of phosphorus entering the Okeechobee watershed.
· Reduce the amount of phosphorus moving from the watershed into the lake.
· Restore a lower lake schedule to encourage the re-growth of the once extensive marsh system.
· Carefully monitor and adaptively manage the STA’s to maintain good water quality entering the Everglades.
· Do not give up on muck removal from the lake’s depths! There may be innovative ways to strip or ‘fix’ the phosphorus. We must not give up!
General Riley’s astute memorandum to Assistant Secretary Woodley wonders what the economic rationale is to clean water before it enters the lake and then clean it again after it leaves the lake. The answer is: “regrettably, we know of no other solution to minimizing the damage to the Everglade’s Restoration effort”.
I spoke to Whit Palmer the financial backer of the algae flow through system on Taylor Creek. I had heard he wanted to talk to me.
We discussed a number of issues then focused on his four acre project that uses algae and hyacinths to remove phosphorus. The system is expensive but requires far less land than STA’s.
He maintained that the system will work and should replace the STA’s that are becoming overloaded and retaining phosphorus.
I asked him why the results of his four acre project were not as successful as they were promised to be. He answered with vigor: “No one informed us that the amount of phosphorus emanating from the dairy barns would be as high or as sustained as it is.”
Whit is also concerned about ’pesticides’ that are showing up in his project.
Paul will have to examine the figures and give us an accurate report.
It seems incredulous that the dairies are still allowed to release water with major amounts of phosphorus despite federal, state and their own investments. Paul points out that the dairies have reduced their emissions from 1000 ppb from 500 ppb, but that puts them way over any ‘limit’ that is meaningful.
I am coming to the conclusion that the dairies are unwelcome in the Okeechobee basin. They are the sword hanging over the future of the lake. Paul believes that they should be induced or coerced to make the necessary changes as the totally self contained Butler dairy has made.
Personally, I believe the dairies are the ‘sword’ hanging over all Lake Okeechobee restoration efforts. The lake’s future is tied to their becoming ‘self contained’. That was the objective 30 years ago.
Bill Riley is ’right‘: we have to make some firm decisions IF the phosphorus levels entering the lake are going to be substantially reduced.
January 25, 2008 Page 3