How do water releases from Lake Okeechobee and rain along the Caloosahatchee affect Sanibel and Captiva estuary areas?
Many communities as far north as Kissimmee (just south of Orlando) feed water into Lake Okeechobee. Before the sugar industry developed and communities were built along the shore to service the sugar industry, Lake O drained naturally to the south into the Everglades. The Everglades are known as the river of grass and the slow gradual flow trapped sediment and provided much needed water to the fragile environment.
Fast forward to future development of roads cutting thru the everglades essentially damning the flow of the mighty river of grass. To compound the problem, Lake O has an earth dyke that keeps communities that service the sugar industry south of the lake from flooding. In periods of higher than normal rain fall, Lake O levels must be lowered. The current flow goes east to Stuart Florida and to the west via the Caloosahatchee.
The water sent down the Caloosahatchee would not be the problem it is today if all of the oxbows in the river had not been removed to allow ships to pass down the river faster. Oxbows are shaped like horse shoes as they cause a river to snake back and forth across the land. These bends slowed the flow of water and also allowed valuable nutrients to be absorbed by the flora along the shore.
With the Southern Everglades "starving for water" the natural solution is to send the water south. To do this, staging areas must be set aside to first contain the release from Lake O and allow excess nutrients to be removed before sending it south. This requires land and construction. All of which is on the table and has been for a few years as government agencies continue to pursue solutions.
Will shutting off the flow from Lake Okeechobee down the Caloosahatchee stop all fresh water run off? No. 2016 is a perfect example of what can happen in a year that has extreme weather. This January due to El Nino weather patterns all across the country, our area received 300% more rain fall that any other January on record. A whopping 16+ inches of rain fell in Southwest Florida. Rain doesn't just land in Lake O. With massive amounts of rain, all the smaller inlets and areas along the Caloosahatchee flowed quickly into the river and out to sea. Rain runoff strips dirt, fertilizers, and tea colored tannins (natural organic by product of fermentation) which appear as brown murky water entering the estuary from the mouth of the river.
As we crossed the line where the rain water met the Gulf water this past week by boat, it was interesting to see that a small ecosystem was created along this line. Leaves were creating a debris field where smaller fish were hiding, which attracted bait fish and the pelicans were diving right into this area.
There is much for us to learn and it's important to understand all the facts. Too much fresh water is harmful to many species that depend on the estuary to survive. A balance in salinity must be kept. Conversely too much salt water is also detrimental to many estuary species.