Sunday, March 20, 2016

The Vexing Problem of Lake Okeechobee

Lake Okeechobee. Click for photo credit.
Until I moved to Florida, I always lived near large lakes. I grew up about 20 miles from Lake Michigan. My father would take us fishing along the shore on occasion or he would rent a charter boat for a day of family fishing. We also had a cabin near Caldron Falls and High Falls, two large reservoirs on the Peshtigo River in Marinette County, Wisconsin. I did my undergraduate degree in Geology at the University of Wisconsin at Oshkosh--a city tucked between the massive Lake Winnebago and its smaller companion, Lake Buttes des Morts. I love to be near lakes. When I moved to Tampa, Florida, for my first job as a college professor, one of my first day trips was to visit Lake Okeechobee.

All of us have seen the lake on a map. It is the 7th largest freshwater lake in the U.S. and is approximately 750 square miles in area. It stands out as an odd central punctuation mark in the lower portion of Florida's pendulum peninsula. It feels like a cycloptic eye of a deep water creature compared to the more emotive facial forms of the Great Lakes--the eyebrows of Lake Superior and Huron and the laugh line of Lake Michigan. While Florida is full of lakes, Lake Okeechobee is unlike the others. It is an odd feature in a state full of odd features.

When I visited Lake Okeechobee for the first time, I was full of anticipation. As a geography nerd, I like to check off important places off my bucket list and the lake was on it. It was such an important place for anyone like myself interested in water resources. The lake is part of American environmental history.

As I approached it on a hot October day, I was surprised to find a vast wall of earth separating me from the lake. While I knew that a levee surrounded it, I didn't expect the wall to be so large. It is impossible to get a glimpse of the lake as one draws near. Of course it is surrounded by levees to avoid flooding.

It reminded me of the levee walls around many rivers in the American South. One can drive right next to a river for tens of miles without seeing anything but high earthen levees that keep the water away from the flat agricultural floodplains during high water seasons. Marjory Stoneman Douglas famously called the Everglades a river of grass. Lake Okeechobee, as one component of the Everglades, is treated very much like a southern river in its hydrologic engineering.

Under natural conditions water flows into Lake Okeechobee from the north, mainly via the Kissimee River which now drains Orlando and a vast area of agricultural land. Due to urbanization and agricultural runoff, the water is now polluted with a nutrients and a number of other contaminants. Prior to building the levee around the lake, clean water would flow out of the lake via a vast sheet flow system that brought water to the Everglades.

It is worth noting that the lake did not form from a sinkhole collapse like most of the other lakes in Florida. It is a low area in a deltaic feature that makes up South Florida. Like Lake Pontchartrain in the Mississippi Delta, Lake Okeechobeee formed as sediment deposited around the lake from fluvial deposition. The sedimentation eventually cut the lake off from the sea. The low area of the lake became a key flow through point of water that washed across the state as a result of abundant subtropical and tropical rainfall that fell in the lake's watershed. As the water flowed south toward the sea, it carried sediment with it that helped to build up the south Florida landscape.

The levee wall around Lake Okeechobee. Click for photo credit.
Of course, as people moved into south Florida, they wanted to stop the natural flow of water out of Lake Okeechobee. Zora Neale Hurston's book, Their Eyes Were Watching God highlights the dramatic events associated with massive flooding that can occur south of the lake during hurricanes. Engineers solved the problem by building a levee and by streamlining flow out of the lake via canals and enhanced drainage, most notably through the Caloosahatchee River which flows from the lake to the Fort Myers/Sanibel Captiva area of the southwest Florida coast.

Of course when we engineer things like the water system of Lake Okeechobee, new problems emerge. The Tampa Bay Times published an interesting article by Leonora La Peter Anton and Craig Pittman this morning that brings together many of the challenges associated with managing water resources in south Florida. Recently Lake Okeechobee filled and caused flooding in the surrounding areas. To alleviate the problem, water managers released tremendous amounts of water into the Caloosahatchee River. Due to the poor water quality, many creatures were killed and ecosystems damaged as the water made its way to the sea. You can read the details here. The beautiful vacation spots of Sanibel and Captiva were impacted.

Sometimes when we engineer nature, we move a problem from one location to another. In this case, the area around Lake Okeechobee was saved. Yet through this protection, damage was done to another part of the state.

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