Weeki Wachee Springs
This historic and world-renowned tourist attraction, once privately owned and now a state park, features Weeki Wachee Spring, one of Florida’s 33 first-magnitude springs. The spring, plus a second-magnitude spring in the park and several smaller springs outside the park, combine to form the seven-mile-long Weeki Wachee River.
Weeki Wachee Springs is the headwaters of the Weeki Wachee River and the largest of nine springs associated with the Weeki Wachee system. The spring group is spread over an area of nearly five square miles. Its contributing area is approximately 260 square miles in Hernando and Pasco Counties, within the Springs Coast Basin.
Weeki Wachee Spring is a first-magnitude spring, discharging an average of 112 million gallons a day. It is located in the town of Weeki Wachee, between Spring Hill and Homosassa Springs. The spring vent is situated at the bottom of a conical depression with gentle side slopes in the center of the spring pool, which measures 165 feet by 210 feet. A boil is visible in the center of the pool. The vent is a small 20-foot by 3-foot opening through exposed limestone rock at a depth of 185 feet. The force of the discharge is too great to allow safe entry except during drought conditions. Divers report that the cave has a roomlike tunnel 55 feet wide, 28 feet high, and 220 feet long. They have been able to map and explore over 6,700 feet of deep passages, and report one pit to be just over 400 feet deep, the deepest recorded in the United States.
The spring pool has a sandy bottom. There is bare limestone near the vent, but none is exposed around the pool edges. The water is clear and light greenish blue, and maintains a constant temperature of 72°F. year-round. The nearest high ground east of the spring consists of rolling sand hills that gently rise to 15 feet above the water level.
The Weeki Wachee River, a short, fast-moving river, flows 7.4 miles westward from the headspring to the Gulf of Mexico at Bayport in Hernando County. Its two principal tributaries are the Mud River and Jenkins Creek. Limestone outcroppings are exposed throughout the river. The lower section of the river has been dredged and channelized with canals for riverfront homes and businesses. The slightly brackish canals and lower portion of the river are tidally influenced by the Gulf of Mexico.
Weeki Wachee Spring and the Weeki Wachee River support a complex freshwater aquatic ecosystem and together are an important cultural and economic resource for the state and local communities. In 2012, 209,000 people visited Weeki Wachee Springs State Park, which employs approximately 80 people.
The springs were developed in 1947 as a unique and popular commercial attraction featuring “live mermaids.” In 2008, the Florida Department of Environmental Protection purchased the property. Weeki Wachee Springs and a small segment of the Weeki Wachee River are now within Weeki Wachee Springs State Park, which encompasses an area of 538 acres. Downstream portions of the river corridor are situated within or on the boundary of the 33,000-acre Chassahowitzka Wildlife Management Area and the 9,000-acre Weeki Wachee Preserve.
Today, visitors can still view the mermaids performing in the spring pool at Weeki Wachee Springs from a 400-seat submerged theater. Other activities include river boat cruises, scuba diving, and canoeing or kayaking on the Weeki Wachee River. Buccaneer Bay, a seasonal water park, has a white sandy beach area and covered picnic pavilions. It offers a water slide, swimming, and snorkeling. Weeki Wachee's animal shows provide audiences with an entertaining and educational look at domesticated birds and reptiles. Shops and facilities are located all around the spring.
Nearly all of the natural land cover around the Weeki Wachee head spring and upper river has been developed or extensively altered. The spring pool and adjacent areas underwent significant development with the construction of the historic tourist attraction, which includes buildings and sea walls adjacent to the waterbody and a large asphalt-paved parking area. In addition, the head spring is approximately 500 feet from the U.S. Highway 19 corridor, which includes a multilane divided highway and commercial development along the highway frontage.
The Weeki Wachee Springs Group consists of at least seven Floridan aquifer system springs, all tidally-influenced, which discharge directly or indirectly into the Weeki Wachee River or nearby tributaries (Figure 1). Weeki Wachee Spring, the only first-magnitude spring in the Group, forms the headwaters of the Weeki Wachee River (Figure 2). Little Spring (aka Twin D’s Spring) is located within Weeki Wachee Springs State Park, just south of the main parking lot. Both springs are fed by deep (around 120m / 400 feet) conduit systems, and discharge relatively fresh ground water. Wilderness, Salt and Mud springs (Figures 3-5) form the headwaters of Mud River, a major secondary tributary of the Weeki Wachee River. Jenkins Creek Spring is one of the springs forming the headwaters of Jenkins Creek, which flows directly into the Gulf of Mexico just south of where the Weeki Wachee River enters the Gulf. Discharge from Weeki Preserve Spring flows northwest through coastal wetlands into Minnow Creek, which discharges directly into the Gulf of Mexico. Except for Weeki Wachee and Little, the other springs described above discharge moderate to highly saline ground water.
The Weeki Wachee Spring springshed extends east across southern Hernando and southeast into north-central Pasco County (Knochenmus et al, 2001). Predominant land use consists primarily of medium-density residential communities, mostly along and extending inland east of U.S. 19-98 for 6 - 8 miles, with mixed upland forest, pasture and single-family residential within the distal portion of the springshed, along the Brooksville Ridge south into Pasco County (Jones et al, 1997). Figure 6 shows the proximity of medium-density residential land use adjacent to and upgradient from Weeki Wachee Main Spring.
Weeki Wachee Spring has been sampled for major ions and nutrients as far back as 1946 by the U.S. Geological Survey (USGS), and the Southwest Florida Water Management District (SWFWMD) has collected a large suite of water quality analytes including nutrients, field and salinity indicators at seven of the major spring vents of this Group during the period from 2002 through 2012. Tables 1-7 summarize the results for selected analytes for each major spring.
Like many Florida springs, nitrate levels in most of the monitored Weeki Wachee Group spring vents have been trending upward during the period of study (2002-2012), with an approximate increase of 0.023 mg/L nitrate + nitrite (measured as N) per year for the Weeki Wachee Spring vent. By the end of 2012, nitrate + nitrite values for Weeki Wachee Main were approaching 1 mg/L (Figure 7). The Department has determined that nitrate concentrations above 0.35 mg/L indicate potential waterbody impairment; this number is based on recent research conducted in Florida spring waters, which found that some of the most prevalent species of algae proliferate when nitrate levels exceed that concentration. Excessive amounts of algae can smother essential habitat for fish and other wildlife, displace native plants, and deplete the amount of DO in the water. Because of elevated and increasing nitrate concentrations along with the proliferation of algal mats, the Department has developed a TMDL for Weeki Wachee Spring (Dodson et al, 2013). Using site-specific alternative criteria, the TMDL document sets an annual average target of 0.28 mg/L nitrate for Weeki Wachee Spring (a 71.1 percent nitrate reduction from current levels), and a 0.20 mg/L nitrate target for the Weeki Wachee River (a 77.3 percent nitrate reduction).
Nitrate + nitrite concentrations have shown considerable variability in the range of measured values since 2002, likely due to aquiferrecharge effects during periods of above-average rainfall. This can be seen when one superimposes nitrate + nitrite values with monthly precipitation measured at Tarpon Springs, the closest long-term rainfall station to Weeki Wachee. This relationship is illustrated in Figure 7, which clearly shows the correlation between high rainfall events and subsequent spikes in nitrate concentrations. High rainfall events can carry additional nutrients from surface sources down into the Floridan aquifer system, and from there to the spring vent. This relationship indicates the possibility that a significant percentage of the discharge waters emanating from Weeki Wachee Spring might be comprised of relatively young ground water.
Monthly rainfall measured at Tarpon Springs indicates a slight increase of about 0.18 inches per year from 2002 to 2012 (Florida Climate Center, 2012). Rainfall totals and nitrate concentrations both show long-term increases during the period of study.
Plotting the ratios of nitrogen isotopes (15NNO3/14NNO3) versus oxygen isotopes (18ONO3/16ONO3) in nitrate measured from ground water can reveal likely nitrate sources: inorganic (chemical fertilizers) or organic (wastewater, septic discharge, animal waste) (Roadcap et al, 2002). Nitrogen and oxygen isotopes were analyzed from single samples collected from Weeki Wachee, Wilderness, Mud and Hernando Salt springs in May of 2013. The results show that all values plot within the domain indicative of an inorganic (fertilizer) nitrogen or soil organic matter source. The data also indicate increased denitrification in samples collected from Mud and Hernando Salt springs; however, elevated salinities measured from these springs might affect these results.
Looking back before 2002, measured nitrate + nitrite concentrations have increased from nearly 0 mg/L in the early 1950’s to almost 1 mg/L during the 60-year period ending in 2013. In a relationship first noted by SWFWMD staff, this increase in nitrate + nitrite levels mirrors Hernando County population growth during the same time period (Figure 8), as U.S. Census data indicates that populatiuion increased from around 10,000 to over 170,000. Much of this population growth and resulting land use change has occurred in the areas immediately east of the spring and upgradient within the Weeki Wachee springshed.
Figure 9 shows the relative nitrate + nitrite concentrations at Weeki Wachee, Jenkins Creek, Wilderness and Weeki Preserve springs. With the exception of Weeki Preserve, all of these springs show nitrate + nitrite values increasing, with almost all current values above the 0.35 mg/L nitrate numeric nutrient threshold. The Department has determined that nitrate concentrations above 0.35 mg/L indicate potential waterbody impairment; this number is based on recent research conducted in Florida spring waters, which found that some of the most prevalent species of algae proliferate when nitrate levels exceed that concentration. Excessive amounts of algae can smother essential habitat for fish and other wildlife, displace native plants, and deplete the amount of dissolved oxygen in the water. Additional work by SWFWMD (1991) at Weeki Wachee indicates that even lower average annual nitrate concentrations will be need to be achieved in order to cause a significant decrease in filamentous algal biomass proliferation; as a result, the TMDL nitrate threshold (restoration target) for Weeki Wachee Spring has been set at 0.28 mg/L, and 0.20 mg/L for the Weeki Wachee River (Dodson et al, 2014).
The other macronutrient of concern in Florida surface waters, orthophosphate, is only present in low concentrations in all Weeki Wachee-area springs, with mean values ranging from 0.005 – 0.012 mg/L (Tables 1-7) during the period of study. While elevated orthophosphate levels are problematic in many of Florida’s lakes and rivers where surface runoff carries this nutrient into these waterbodies from its sources, measured orthophosphate levels are low in springs. This is due to its attenuation within limestone aquifers where, given enough time, orthophosphate reacts with calcium carbonate to produce low-solubility calcium phosphate minerals which remain within the host rock (Brown, 1981). Given enough time, this effectively removes orthophosphate from the waters within the aquifer, and is the probable geochemical mechanism by which “hard rock” phosphate deposits have developed in the state.
The submerged aquatic vegetation currrently present in the Weeki Wachee Head Spring and the upper Weeki Wachee River are both dominated by patches of dark green filamentous algae (Figure 10-11). This represents a fundamental shift in the predominant submerged aquatic vegetation species from the once-dominant native tapegrass (Vallisneria americana) to filamentous algae (Lyngbya wollei).
Salinity indicator analytes (sodium, chloride, sulfate and specific conductance) delineate two populations of spring water types within the Weeki Wachee Springs Group: fresh (Weeki Wachee, Little springs) and moderate to highly saline (Wilderness, Mud, Hernando Salt, Jenkins Creek, Weeki Preserve springs). Weeki Wachee and Little springs are both located approximately 7.8 km (5 miles) east of the Gulf of Mexico, while the remaining Weeki Wachee Group springs are all located within 2.7 km (1.7 miles) of the Gulf.
Salinity indicators in Weeki Wachee Spring (Figure 12) show a steady increase over the study period, and further investigation shows that these increasing trends can also be seen in data from Little, Hernando Salt, and Jenkins Creek springs (Figure 13). Weeki Wachee Spring salinity indicators have been increasing since the early 1960’s, with chloride and sulfate values roughly doubling over the last 60 years. The longer-term measured increases in salinity indicators reflect potential upconing of deeper, more saline ground water due to increasing fresh ground water withdrawals from the Floridan aquifer system, decreasing precipitation patterns, steadily rising sea level or a combination of these causes.
Dissolved oxygen (DO) levels are important for fish and other biota, and are generally measured at levels below 5 mg/L in fresh ground water issuing from spring vents. The levels measured in the Weeki Wachee Springs Group are within this normal ground water range, with mean DO values in the 1.23 – 2.66 mg/L range (Tables 1-7). Some fish species can tolerate lower dissolved oxygen levels, and thrive in spring vent environments. Dissolved oxygen levels generally rise rapidly in surface waters downstream from spring vents, due to plant respiration; however, other than filamentous algae, the headwaters of the Weeki Wachee River are largely devoid of submerged aquatic vegetation.
Boron, not known to occur naturally in high concentrations in fresh Floridan aquifer system ground water, has recently been sampled as a possible wastewater tracer in wells and springs, due to its widespread use in laundry detergents. Historic (2002-2012) mean boron concentrations from Weeki Wachee Main Spring (11 boron samples), Little (Twin D’s) Spring (1 boron sample) and Hernando Salt Spring (1 boron sample) were compared to historic chloride concentrations (from Tables 1, 2 & 5), and boron/chloride ratios were calculated:
Weeki Wachee Main Spring: Boron/Chloride ratio = 0.000344
Little (Twin D’s) Spring: Boron/Chloride ratio = 0.002179
Hernando Salt Spring: Boron/Chloride ratio = 0.000230
The above values from Weeki Wachee Main and Little springs are significantly above the mean boron/chloride ratio measured in Atlantic Ocean seawater sampled along the U.S. coastline from south of Cape Cod to Bermuda, which is 0.000240 (Rakestraw et al, 1935). The ratio for Little Spring is almost an order of magnitude higher than the normal seawater ratio, but this is based on only one boron sample. If one assumes that boron/chloride ratios in the Atlantic Ocean are similar to boron/chloride ratios of the small percentage of seawater entrained in Floridan aquifer system ground water, these numbers potentially indicate a human boron wastewater component present in spring discharge from these two spring vents. The boron/chloride ratio for Hernando Salt Spring was just slightly below the North Atlantic Ocean value, indicating no anthropogenic boron enrichment.
Sucralose is used as an artificial sweetener. Because it passes through water treatment systems largely intact, it has recently been used as a potential human wastewater tracer. Only one sample of sucralose has been collected to date from Weeki Wachee, Jenkins Creek, Mud, Hernando Salt and Wilderness springs; all in 2013. Sucralose was only detected at Jenkins Creek Spring (0.063 mg/L). A very low potential detection (value between the laboratory method detection limit and the practical quantitation limit) was found at Weeki Wachee Spring. No sucralose was found in samples collected from Wilderness, Hernando Salt and Mud springs. Sucralose detections might indicate possible wastewater influences within the springshed.
Find References and View Full Size Images:
Both the Weeki Wachee Spring and River are rich with freshwater and saltwater fishes, as well as species such as loggerhead musk turtles and limpkins that feed on Florida apple snails. The river also provides important habitat for endangered West Indian manatees. These huge, gentle animals, averaging 1,000 pounds, eat only aquatic plants. They cannot survive for extended periods in water colder than about 63°F. The river flows through low-lying, densely forested coastal swamps and marshes that also contain abundant wildlife.
There are some native aquatic grasses in the spring pool, and thick, filamentous algae (Lyngbya wollei), first documented by the SWFWMD in 1991, cover most of the spring bottom and are also present in the river. The algal overgrowth is caused by excessive nutrients (nitrate) in the ground water discharging from the springs. Lyngbya is an invasive algae that grows and spreads rapidly. It attaches itself to plants and the bottoms of waterbodies, forming large mats. These mats grow and then break off, spreading to other areas. Lyngbya crowds out native vegetation, disrupts the natural filtration process, and decreases the amount of good habitat for fish nurseries. It can also reduce the aesthetic value of clear springs or stream runs.
In addition to L. wollei, floating plants, cattails, and hydrilla are causing problems in the Weeki Wachee River.
Some of the recreational activities in Buccaneer Bay have resulted in sediment erosion and deposition in the spring basin and upper river, contributing to the smothering of vegetation and a loss of submersed aquatic vegetation (SAV).
Find References and View Full Size Images:
In 2009, residential, forest, and agricultural areas were the predominant land uses in the Weeki Wachee Spring contributing area, covering 27%, 23%, and 23%, respectively. Wetlands covered 15% of the contributing area.
Weeki Wachee Spring has the highest nitrate concentrations of the springs in the Springs Coast Basin. The increase in nitrates since the 1940s mirrors the growth in the area’s population and the development of large, coastal residential subdivisions adjacent to Weeki Wachee in Hernando County. Spring Hill, with about 60,000 residents, is the largest of these subdivisions. In addition to the increased use of fertilizer on golf courses and residential landscapes, as of 2010 there were approximately 16,662 septic tanks in the contributing area of the springs. There appears to be about a 15-year lag between population and spring nitrate increases.
The river was designated as an Outstanding Florida Water (OFW) in 2003, meaning that it is worthy of special protection because of its natural attributes.
In 2009, the Department verified the elevated nitrate concentrations and the excessive growth of algae and low levels of dissolved oxygen (DO) in Weeki Wachee Spring and the upper segments of the Weeki Wachee River that were causing an imbalance in natural populations of aquatic plants and animals. In 2014, the Department established a Total Maximum Daily Load consisting of nitrate reductions of 71.1% in Weeki Wachee Spring and 77.3% in the Weeki Wachee River (Dodson et al, 2014). A TMDL is the maximum amount of a given pollutant that a waterbody can assimilate and still meet water quality standards. The restoration of ecological health in the spring and river depends heavily on the active participation of stakeholders in the springshed, who are required to develop projects to reduce nutrient concentrations.
To implement the TMDL, a Basin Management Action Plan is currently being developed for the spring and river. It will include nutrient reduction allocations among stakeholders in the springshed, projects to achieve specific reductions, timelines for initiating and completing projects, identification of funding opportunities, agreements, local ordinances, local water quality standards and permits, and follow-up monitoring.
In 2008, the SWFWMD developed a Minimum Flow and Level (MFL) recommendation for the Weeki Wachee River system designed to protect and preserve the amount of water needed for manatees to shelter during cold spells, and to protect essential habitat for other wildlife such as fish and invertebrates.
The SWFWMD’s Weeki Wachee Stormwater Project, completed in 2008, captured and treated stormwater runoff from U.S. Highway 19 and the Weeki Wachee Springs State Park parking lot.
In 2009, SWFWMD completed a restoration project at Weeki Wachee, where divers removed more than 6,000 cubic yards of sediment between the spring vent and the vicinity of the state park's boat dock. The project’s goal was to improve water quality in the headspring and the upper river, and to enhance the overall natural system. The district continues to combat the reinfestation of Lyngbya in this area.
A number of other projects are ongoing or proposed. Efforts are currently under way to improve stormwater management in Weeki Wachee Springs State Park. The implementation of low-impact development has been proposed in Weeki Wachee Rogers Park. Both of these projects will reduce contaminated runoff to the spring’s contributing area. At a cost of $2.6 million, the proposed U.S. 19 Reclaimed Water Transmission Main Project would reduce ground water use by constructing a reclaimed water transmission main and converting abandoned force mains to provide reclaimed water to the Timber Pines Golf Course and residential communities in the Spring Hill area.
Find References and View Full Size Images:
Here is a “Contact Tab” list you can use for Weeki Wachee:
Florida Department of Environmental Protection
Water Quality Evaluation & TMDL Section
Rick Hicks, PG Administrator
Contact for: General springs information
Springs Coast Water Quality Restoration Program
Terry Hansen, Basin Coordinator
Phone: (850) 245-8561
Contact for: Information on basin management action plan (BMAP)
Local Government and Water Resource Agencies
- Southwest Florida Water Management District (http://www.swfwmd.state.fl.us/)
- Hernando County (http://www.hernandocounty.us/)
- Pasco County (http://www.pascocountyfl.net/)
- Florida Geological Survey
- U.S. Geological Survey – Florida Water Science Center (http://fl.water.usgs.gov/infodata/)
- Florida's water: ours to protect
Citizen Stakeholder and Watershed Organizations
- Gulf Coast Conservancy (http://www.gulfcoastconservancy.org/index.htm)
- Friends of Weeki Wachee Springs State Park (http://friendsofweekiwachee.com/HOME)
- Hernando County Groundwater Guardian (http://www.hernandocounty.us/utils/groundwater/)
- Hernando Environmental Land Protectors (http://flhelp.nccsfl.com/)
Parks and Conservation Areas
- Chassahowitzka Wildlife Management Area (http://myfwc.com/viewing/recreation/wmas/lead/chassahowitzka/)
- Weeki Wachee Springs State Park (https://www.floridastateparks.org/park/weeki-wachee)
Find References and View Full Size Images:
Find Related Info
Weeki Wachee Springs, , , ,