Note: This is an Earthcache. There is no physical cache to find. Logging this Earthcache requires that you undertake an educational task relating to the specific Earth Science at the site.
Prior to logging this cache, click on Message this owner, or send an email with answers to the following questions:
- According to the sign at GZ, how many gallons of water pour out of Blue Spring each day?
- Continue down the boardwalk to N28 56.853 W081 20.365 There is a sign between the boardwalk and the spring run that talks about a problem. What was that problem?
- Continue to the end of the boardwalk N28 56.864 W081 20.379. What is your estimated diameter of the spring pool?
- Is the spring discharging with enough force to “boil” the surface of the water?
- Required to log this cache: Please provide a photo of yourself or a personal item in the picture to prove you visited the site. Upload the photo with your log.
Blue Spring State Park
This Earthcache is located in Blue Spring State Park. An admission fee is charged. Amenities include swimming, snorkeling, scuba, boating, fishing, camping, rental cabins and picnicking. This is a very popular park on weekends. Parking is limited. Your odds of entry will increase with early arrival. The spring and spring run are closed to swimming and boating during manatee season, mid-November through March, but an excellent boardwalk provides viewing of the manatees.
Blue Spring is the largest spring on the St. Johns River, and a designated Manatee Refuge. In the winter it is home to a growing population of West Indian Manatees. This Earthcache will take you down the short Blue Spring Trail to the headwater of the spring.
Springs are natural openings in the ground through which water beneath the surface discharges into hydrologic features such as rivers. Blue Spring is at the end of a complex drainage system in an aquifer that underlies the land surface. An aquifer is any layer of rock, sand, or other material through which water can flow. Blue Spring is a natural breach in a clay layer that separates the surface sands of the surficial aquifer system from the limestone and dolomite rocks of the Floridan aquifer system. The principal features of a spring system include an upland area where rainfall seeps into the surficial aquifer system. There also must be sinkholes or gaps in the clay layer where water can flow downward into the Floridan aquifer system. Inter-connected solution cavities and cracks in the rocks of the Floridan aquifer system conduct large quantities of water to the spring vent.
German. E.R., 2008, Volusia Blue Spring--A Hydrological Treasure: U.S. Geological Survey Fact Sheet
Most of the water discharging from Blue Spring is from rain that falls on the land area within the springshed, which is about 130 square miles. Ground water that discharges from the spring is a mixture of water from different parts of the springshed and of various ages. Some of this water from rainfall mixes with ancient seawater still present in deep layers of rock. This explains why the water discharged from Blue Spring has historically been described as foul smelling and was not used as a drinking water source.
The temperature of spring water discharging from the Floridan aquifer system is nearly constant. Geologic material is a good insulator, and rocks and sediments buffer changes in the temperature of ground water that might result from recent rains. Blue Spring averages 73° F year round. This makes it a perfect winter home for the West Indian Manatees.
Manatees are gentle, slow-moving mammals related to the dugong, and more distantly, the elephant. They are herbivores and eat a wide variety of aquatic plants. Adult manatees are about 10 feet long and weigh between 1,500 and 2,200 pounds. They cannot survive for extended periods in water colder than about 63° F. In the winter, manatees must seek warmer waters, such as Blue Spring. On cold mornings, large numbers of manatees can be seen in the spring run.
Sources: www.floridasprings.org; www.floridastateparks.org
