"Here's something hard to picture today: the lagoon used to be one open, continuous body of water. No causeways slicing it up. No long raised roads blocking the flow. You could paddle from one end to the other without a single bridge stopping you. The water moved freely."
One Open Lagoon
Before causeways, the lagoon was one open system: Five hundred years ago — and really up until the 1900s — the Indian River Lagoon was a single, continuous body of water. There were no causeways crossing it. What a causeway is: A causeway is a raised road built across water — basically a long embankment of fill (sand, dirt, rock) with a road on top, sometimes with a bridge or two for boats to pass. The Space Coast's major causeways (like the Melbourne, Eau Gallie, and Pineda causeways, and the NASA Causeway) were all built in the 1900s and 2000s. The open lagoon: Before these were built, the lagoon was unbroken. Water moved freely from north to south, and between the lagoon and the ocean (through natural inlets). Tides flushed the whole system. Fish, manatees, and turtles could travel the full length without obstruction. Why this matters: An open lagoon flushes. Stagnant water — trapped behind causeways and dead-end canals — is the enemy of a healthy estuary. The pre-development lagoon's openness is a big reason its water was so clear: it exchanged water constantly.
