The Rainbow Springs run is one of the largest spring runs in Florida. It averages a discharge of over 400 million gallons of water per day. The run is 5.7 miles long and joins the Withlacoochee River which is a black water river, near the town of Dunnellon. Unlike most other major spring runs in Florida the spring discharge comes from several vents that are scattered over the first mile of the run. It is characterized by a high level of submersed aquatic plants. Ribbon or tape like plants are the most common. Its waters stay at 72 degrees Fahrenheit year round. Because of this and the high water quality it is a very popular recreational destination.
For more information: http://www.dep.state.fl.us/coastal/sites/rainbow/info.htm