“Take your hands off my neck, ” she whispers…
The Indian River Lagoon is not a “river;” she is a “lagoon.” She has no “headwaters “like a true flowing river, but is rather a 156 miles depression along 40% of the Florida’s east coast. The lagoon once contained naturally cleaned waters from surrounding vegetated lands, brooks, larger tributaries and had the benefit of naturally opening and closing inlets to the ocean.
Today not only are its inlet fixed, but the lagoon’s water contains run off from polluted/populated surrounding surface waters, naturally rising and falling salty/nutrient filled groundwaters, and those of impacted water bodies like the Crane Creek in Melbourne or the St Lucie River in Stuart. These water bodies have been channelized and engineered to take on sometimes as much as 50% more fresh water through drainage of lands and lakes than than Mother Nature planned; of course, it ends up in the IRL as it goes to sea.
The lagoon’s water moves only through tides and wind. In some areas of the lagoon where there are no inlets, it is estimated that the water can remain “there” for over three years or more. Even close to an inlet, like here in Sewall’s Point, causeways heavily impact the ability of the lagoon’s water to move and flow cleaning itself, becoming becoming stagnant.
The lagoon was formed over many ice-ages with the rise and fall of the ocean. According to the History of Martin County, “evidence of comparatively recent rise of ocean levels during the past 10,00 years is frequently found in the spoil and dredging of operations along the Indian River through fossils of giant mammals.”
It may have taken thousands of years for Nature to form the lagoon but mankind is close to destroying it in just under 100; one of the primary ways of doing such was/is through the building of causeways to support bridges to Hutchinson Island.
There have been and will be opportunities to improve this situation, most recently in 2004, in Martin County, when the Ernest Lyons Bridge located between Sewall’s Point and Hutchinson Island, was being rebuilt, this problem was addressed, but not corrected, as the public at the time was unwilling to give up its access to the causeways. The causeways were lessened but not removed.
The causeways don’t just impact the water flow but also the lagoon’s wildlife. I remember my parents telling me stories in my youth about the fisherman of early Jensen noting that the causeways sticking out into the “river”confused the migratory fish that had followed its shoreline as navigation to the inlets for thousands of years.
We will have an opportunity to rebuild the bridges before the next thousand years, my vote is remove the causeways and stop choking the already suffocating Indian River Lagoon.
1985 SFWMD report notes problems of causeways: (http://www.sfwmd.gov/portal/page/portal/pg_grp_sfwmd_watershed/portlet%20-%20coastal%20ecosystems/tab1806037/irlswim99/appendixb.pdf)
2014 Florida Today letter to the editor: (http://www.floridatoday.com/story/opinion/readers/letters/2014/05/19/letter-causeways-contribute-lagoon-pollution/9169601/)