Algae Algae everywhere – Where’s a Fish to think?


We have all seen the stories about land in the Everglades agricultural Area thissummer.  I was asked to give a presentation at a national conference in Orlando recently about water management in Florida.  It was a fun paper and most of the people there were not from Florida, so it was useful for them to understand the land of water.  Florida has always been a land shaped by water.  Initially it was too much, which frustrated federal soldiers trying to hunt down Native Americans in the 1830s.  In 1881, real estate developer Hamilton Disston first tried to drain the swamps with canals.  He was not successful, but Henry Flagler came through a decade later and constructed the east coast railroad in the 1890s.  It is still there, 2 miles off the coast, on the high ground.  However water limited development so in 1904, Napoleon Bonaparte Broward campaigned to drain the everglades.   Broward’s efforts initiated the first land boom in Florida, although it was interrupted in the 1920s by hurricanes (1926 and 1928) that sloshed water out of Lake Okeechobee killing people and severely damaging property in Miami and around Lake Okeechobee.  A dike was built (the Hover dike – it is still there). However, an extended drought occurred in the 1930s.  With the dike preventing water from leaving Lake Okeechobee, the Everglades became parched. Peat turned to dust, and saltwater entered Miami’s wells. When the city brought in an expert to investigate, he found that the water in the Everglades was the recharge area for the Biscayne aquifer, the City’s water supply.  Hence water from the lake needed to move south.

Resiliency has always been one of Florida’s best attributes.  So while the hurricanes created a lot of damage, it was only a decade or two later before the boom returned.  But in the late 1940s, additional hurricanes hit Florida, causing damage and flooding from Lake Okeechobee prompting Congress to direct the Army Corps of Engineers to build 1800 miles of canals, dozens of pump stations and other structures to drain the area south of Lake Okeechobee.  It is truly one of the great wonders of the world – they drained half a state by lowering the groundwater table by gravity canals. To improve resiliency, between 1952 and 1954, the Corps,  in cooperation with the state of Florida, built a levee 100 miles long between the eastern Everglades and the developing coastal area of southeast Florida to prevent the swamp from impacting the area primed for development.

As a part of the canal construction after 1940, 470,000 acres of the Everglades was set aside for farming on the south side of Lake Okeechobee and designated as the Everglades Agricultural Area (EAA).  However water is inconsistent, so there are ongoing flood/drought cycles in agriculture.   Irrigation in the EAA is fed by a series of canals that are connected to larger ones through which water is pumped in or out depending on the needs of the sugar cane and vegetables, the predominant crops.  Hence water is pumped out of the EAA, laden with nutrients.  Backpumping to Lake Okeechobee and pumping the water conservation areas was a practice used to address the flooding problem.

There was an initial benefit to Lake Okeechobee receiving nutrients.  Older folks will recall that in the 1980s , the lake was the prime place for catching lunker bass.  That was because the lake was traditionally nutrient poor.  That changed with the backpumping which stimulated the biosystem productivity.  More production led to more biota and more large fish.  This works as long as the system is in balance e- i.e. the nutrients need to be growth limiting at the lower end of the food chain.  Otherwise the runaway nutrients overwhelm the natural production and eutrophication results.  Lake Okeechobee is a runaway system – the algae now overwhelm the rest of the biota.  Lunker bass have been gone for 20 years.

The backpumped water is usually low in oxygen and high in phosphorus and nitrogen, which triggers algal progressions, leading to toxic blue-green algae blooms and threaten lake drinking water supplies.  Think Toledo. Prolonged back pumping can lead to dead zones in the lake, which currently exist.  The nutrient cycle and algal growth is predictable.

The Hoover Dike is nearly 100 years old and while it sit on top of the land (19 ft according to the Army Corps of Engineers), there is concern about it being breached by sloshing or washouts.  Undermining appears in places where the water moves out of the lake flooding nearby property.  So the Corps tries to keep the water level below 15.5 ft.  During the rainy season, or a rainy winter as in 2016, that can become difficult. If the lake is full, that nutrient laden water needs to go somewhere.  The only options are the Caloosahatchee, St. Lucie River or the everglades.  The Everglades is not the answer for untreated water – the upper Everglades has thousands of acres of cattails to testify to the problem with discharges to the Everglades.  So the water gets discharged east and west via the Caloosahatchee and St. Lucie River.

The nutrient and algae laden water manifests as a green slime that washed onto Florida beaches in the Treasure coast and southwest Florida this summer, algae is actually a regular visitor to the coasts.  Unfortunately memories often fail in temporal situations.  The summer 2016 occurrence is reportedly the eighth since 2004, and the most severe since 2013.  The green slime looks bad, can smell bad, kills fish and the 2016 bloom was so large it spread through estuaries on both coasts killing at least one manatee.  One can see if from the air – try this link:

 

https://www.google.com/search?q=algae+florida+aerial&rlz=1C1CAFA_enUS637US637&espv=2&biw=1194&bih=897&tbm=isch&imgil=-znOtKN1py0w1M%253A%253BR2WKOUpBlkwQUM%253Bhttp%25253A%25252F%25252Fabcnews.go.com%25252FUS%25252Ftoxic-algae-blooms-infesting-florida-beaches-putting-damper%25252Fstory%25253Fid%2525253D40326610&source=iu&pf=m&fir=-znOtKN1py0w1M%253A%252CR2WKOUpBlkwQUM%252C_&usg=__KgNR31PY5qxleBf1KST7DWY2mXo%3D&ved=0ahUKEwiqyKK6uJvPAhWr6oMKHdt7C5oQyjcIKg&ei=QNvfV6qoLavVjwTb963QCQ#imgrc=-znOtKN1py0w1M%3A

 

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