• Water is the only common substance on the earth that appears in all three of its natural states within the normal range of its climatic conditions, sometimes at the same time. The three states include liquid, solid, and gas or — water, ice, and water vapor.
• Most liquids contract steadily as they freeze. Water, however, contracts only a certain amount, but begins to expand as it reaches its freezing point of 0°C (32°F). This expansion can fracture rocks.
• An unusual characteristic of water is its heat capacity, that is, its ability to absorb heat without becoming extremely hot itself. Think of a swimming pool on a hot day— does the water ever get as hot as the air temperature?
• Water has a high surface tension, that is, the ability of a substance to stick to itself. Certain light items can float on water and small insects can walk on water. It is estimated that it would take a force of 210,000 pounds to pull apart a column of water 1 inch in diameter.
• Water has a tremendous ability to stick to surfaces; this is called adhesion. In a very narrow column such as a plant root or stem, the combination of surface tension and adhesion pulls water upward. This movement is known as capillarity.
• A remarkable property of water is its ability, given enough time, to erode or, wear away, the hardest of rocks.
• The human body is 66% water.
• Of the world’s total freshwater supply, over two-thirds is found underground.
• About 82% of our blood is water. Water helps digest our food, take in oxygen, transport body wastes, and control body temperature.
• Only 3% of the water found on the earth is freshwater; 97% is salt water, found in the oceans and salty lakes.
• Only 1% of the earth’s water supply is in a form that is usable by animals, plants, and humans.
• Water data are often measured in millions of gallons per day (mgd). A million gallons is roughly equal to 20,000 full bathtubs.

Fast facts about the St. Johns River

• The St. Johns River is the longest river in Florida — 310 miles. It is one of the few rivers in the United States that flows north.
• The land area that drains into a water body is called a drainage basin, or “watershed.” The St. Johns River is divided into three drainage basins.
• Because the river flows north, the upper basin is the area to the south that forms its marshy headwaters in Indian River and Brevard counties. The middle basin is the area in central Florida where the river widens, forming lakes Harney, Jesup, Monroe and George. The lower basin is the area in northeast Florida from Putnam County to the river’s mouth in Duval County, where the river empties into the Atlantic Ocean.
• The width of the river varies. It is a flat marsh at its headwaters and averages about two miles in width between Palatka and Jacksonville. It widens to form large lakes in central Florida.
• The total drop of the river from its source in marshes south of Melbourne to its mouth in the Atlantic near Jacksonville is less than 30 feet, or about one inch per mile, making it one of the “laziest” rivers in the world.
• Because the river flows slowly, it is difficult for the river current to flush pollutants.
• Major pollution sources include discharges from wastewater treatment plants and stormwater runoff from urban and agricultural areas. This runoff carries pesticides, fertilizers and other pollutants into canals, ditches and streams that lead to the river. River pollution is concentrated around urban areas.
• Salt water enters the river at its mouth in Jacksonville. In periods of low water, tides may cause a reverse flow as far south as Lake Monroe — 161 miles upstream from the river’s mouth.
• Major tributaries, or smaller streams and rivers that flow into the St. Johns River, include the Wekiva River, the Econlockhatchee River and the Ocklawaha River.
• The St. Johns River is an ancient intracoastal lagoon system. As sea levels dropped, barrier islands became an obstacle that prevented water from flowing east to the ocean. The water collected in the flat valley and slowly meandered northward, forming the St. Johns River.
• Jacksonville is said to be at the mouth (place where the river enters the ocean) of the St. Johns River but is, in fact, located 24 miles from the actual mouth of the river.
• The St. Johns River usually flows north, but because it is tidally influenced and relatively flat, it reverses its flow twice a day.
• The St. Johns River begins, or rises, in Okeechobee County.
• The average depth of the St. Johns River is 11 feet and the maximum depth is 80 feet, which occurs at high tide in downtown Jacksonville.
• The St. Johns River is a naturally “dark water” river. The color is a product of runoff from forested areas that contains organic stains, or tannins.

Historical facts about the St. Johns River

• Before European involvement in North America, the Timucuan Indians called the St. Johns River “Welaka” — or river of lakes.
• In the early 1500s, Spanish seamen called the river “Rio de Corrientes” —or river of currents.
• In 1562 — almost 50 years before the settlement in Jamestown — the French established Fort Caroline on a high bluff overlooking a river they called “Riviere de Mai” (River of May) because they arrived there on May 1.
• In 1565, Spanish soldiers marched north from St. Augustine, captured Fort Caroline and slaughtered the French. The Spanish renamed the river “San Mateo” to honor the saint whose feast followed the day they captured the river.
• Later, the river was renamed “Rio de San Juan” after a mission near its mouth named San Juan del Puerto. The English translation of the name Rio de San Juan — St. Johns River — lasted through English, Confederate and American possession of the river and remains today.
• Soon after England acquired Florida in 1763, King George III sent botanist John Bartram to explore Florida. His son, William Bartram, stayed in Florida and published his book Travels in 1791. It describes his exploration of the river as far south as Lake Harney.
• In the 1800s, steamboats made the St. Johns River a popular winter destination for northerners. By the 1860s, several steamers were making weekly round-trips from Charleston and Savannah to Jacksonville and Palatka, and other settlements.
• In the 1900s, miles of floodplain were drained to make room for indigo, sugar cane, citrus and other profitable crops. Encroachment through draining of the headwater marshes at the river’s southern end was neither planned nor controlled. More than 70 percent of the marsh was claimed for agricultural and urban uses.
• In 1954, Congress authorized flood-control works in the southern part of the St. Johns River. To store water and to move floodwaters, large reservoirs and canals were designed by the U.S. Army Corps of Engineers (Corps).
• The Corps’ project was halted in the 1970s. In 1974, the project was deemed unacceptable for environmental reasons.
• In 1980, a redesigned project by the St. Johns River Water Management District favored restoring wetlands to hold and release floodwaters and managing water levels to simulate natural marsh conditions. Since the project began, the District has restored more than 150,000 acres of original marsh, an area about the size of Delaware.