Category Archives: Current Issues

VOLUSIA BLUE SPRING – DECLINING FLOW

Dingbao Wang and Jonathan Griffen

The University of Central Florida’s Walter and Betty Boardman Foundation contracted with Dr. Dingbao Wang, Assistant Professor at the University of Central Florida, to explore the causes for the decline in flow at Volusia Blue Spring.

Summary
Blue Spring has been experiencing a decline in discharge since 1976. From 1976 to 2012, the annual average discharge decreased from 152 ft3/s to 127 ft3/s.  Precipitation trends were analyzed for a possible explanation of the declining discharge, but no significant decreasing trend was observed.  Increasing evaporation rates were another factor considered. Due to the limited evaporation data, temperature trends, which correlated fairly well with the available evaporation data, were used as an approximation of evaporation and extended the analysis prior to 1983. From this record, it was observed that the temperature trend did not correlate closely with the discharge trend. Starting about 1952, the temperature had been on a declining trend, which ended around 1989 and began to increase in 2002.  Discharge, on the other hand, had been on a declining trend since 1976.  That is, though increasing evaporation rates may have had some impact on the declining discharge, it is likely not the primary cause of the trend.

From the population and water use data it is evident that human activities have had a significant impact on the springshed, especially around the 1970’s, as demonstrated by the change in land use which resulted in a loss of wetlands and an increase in urban area.   As indicated in the land use data, water use data, and population data, a significant increase in the impact of human development on the springshed was observed. First, there was a 61% increase in total water use for the springshed from 1965 to 1975, which accelerated to a 58% increase from 1975 to 1980 (which is nearly the same rate in half the time). Also, there was a significant increase in the population growth rate beginning in 1950 and then especially after 1970.  Finally, there was a significant increase in the urban area, particularly from 1973 to 1995 (31.1%).
Blue Spring Flow 2

Municipal Update – Deltona

by Jerry Mayes, Economic Development Manager

     In recent years the City of Deltona has taken several meaningful steps toward addressing regional conservation issues. The recent economic downturn has affected many projects within the region but Deltona has moved forward on projects that either have or will have major positive impacts.

In conjunction with the St. Johns River Water Management District, a major storm water retention system was agreed to. In April of 2013 the City dedicated a new, nature based park, aptly named Audubon Park. Let’s just say it wasn’t pretty to start with, but with the work of our engineers, contractors, Audubon volunteers, and City staff, it is now a tranquil park with a growing nature based reputation. The primary park entrance is at Doyle Road and Lush Lane (adequate parking available), plus an additional bicycle and walking entrance located on the ‘River-2-Sea Trail’ that runs along the southern end of the City and Volusia County.
audubon park

Plant and lawn watering is a major source of potable water consumption. The use of reclaimed water will save pumping water from the Floridan aquifer. In 2013, Deltona’s Commission voted to build a new $20 million waste water treatment facility on the Eastern side of the City. Currently under construction, this new facility will allow commercial development without the necessity for additional septic tanks for business development. This facility will provide reclaimed water for irrigation purposes to businesses, schools, and other development. Thus, potable (aquifer supplied) water will be conserved and existing irrigation wells can be capped. Upcoming will be the construction of a $5 million reclaimed water main, connecting the Eastern facility to the Fisher (Western) facility. This will also supply reclaimed water for irrigation purposes along Doyle Road.

The City is also developing a new recharge area on City owned property near Alexander Avenue. The area will recharge both stormwater and reclaimed water. In the next 3 to 5 years the City will also have treatment facilities for stormwater, which will allow it to be used as reclaimed water in the future. The City also has plans for the use of reclaimed irrigation water on future sports fields at the Alexander location, and later, at the Dewey O. Booster Sports Complex.

With this new waste water treatment facility supplementing the current Western (Fisher) Facility, additional reclaimed water will be available for watering on the Western side of the City. While reclaimed water is in use, not all reclaimed water can necessarily be used on a day-to-day basis by one utility. So that this water would not be wasted, the City, in conjunction with the Water Management District, plans to build a 1 million gallon reclaimed water storage tank so that water can be better utilized for irrigation. Also, the City, in conjunction with Deland, Orange City, and Volusia County, as a part of the Blue Springs MFL Prevention and Recovery Strategy (with WMD approval), will be a part of an interconnected reclaimed water distribution system among the four entities. This will allow reclaimed water to be more efficiently used over all of Southwest Volusia County.

To conserve current potable water use and to positively affect the aquifer, the City adopted “Conservation Block Rates”.  Basic water consumption is affordable, while high water consumption is priced on increasing rate tiers. This was done to reduce the amount of potable water for outdoor (read “irrigation”) usage by residents. This has caused the use of potable water consumption to be reduced by 1.5 to 2 million gallons daily. In March, 2010, the City adopted “Waterwise Florida Irrigation” and in February, 2014 adopted “The Florida-Friendly Landscaping Guide to Plant Selection and Landscaping Design”. These were adopted to assist in the reduction of irrigation needs on residential lawns and are found in the Deltona City Ordinances under 110-808(d). Lastly, the model FDEP fertilizer ordinance was adopted by the City in 2013.

The City of Deltona has taken water conservation seriously, with major commitments to project development and funds expenditures, to make our City, and Southwest Volusia County, a preferred and desirable place to live, work and play.

Springshed

The water that flows from Blue Spring comes from rainfall in the 130 square mile springshed, which encompasses portions of five cities within Volusia County. The rainfall seeps down into the aquifer and slowly flows through the limestone
before discharging at the spring. It takes less than 43 years for most of the rainfall to make its way through the aquifer to the spring. Along the way, the water picks up pollutants that are ultimately discharged at the spring and that affect the ecological health of the spring run.

Blue Spring Springshed

Spring Flows

Blue Spring, one of more than a thousand springs in Florida, is the largest spring on the St. Johns River and the 17th largest in Florida in terms of rate of discharge. With an average discharge of 102 million gallons per day, Blue Spring is one of Florida’s 27 first-magnitude springs. The average daily discharge is equivalent to a pool of
water the size of a football field (360 x 160 feet) that is 240 feet deep. The discharge varies based on rainfall and withdrawals of water from the springshed. Blue Spring is a designated manatee refuge, and an important part of the St. Johns River ecosystem.

Water Quality Trends

Nutrient pollutants in springs adversely affect the aquatic ecosystem by promoting algae and undesirable plant growth. Nitrate is one of the nutrients with a particularly harmful effect on springs. Nitrates enter the groundwater through atmospheric deposition, fertilizers, and animal and human wastes, and remain stable even as
they pass through the aquifer. An overall increasing trend in concentrations of nitrate in Blue Spring appears to have occurred since 1975. Since 1998, concentrations of nitrate have averaged over nine times the expected
background concentration. This increase coincides with visible declines in the aquatic habitat of the spring run, which is of particular concern to the Alliance.

Manatee Refuge

Blue Spring is well known as a winter refuge for the Florida manatee. 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. Adults are
about 10 feet long and weigh between 1,500 and 2,200 pounds. During the warmer months, manatees travel widely through warm, shallow, coastal estuarine waters of central and south Florida. They cannot survive for extended periods
in water colder than about 68 degrees, so they migrate to warmer spring waters during the cold winter months.

The number of manatees using the Blue Spring run as a winter refuge is increasing. Since the mid-1980s, the winter population of manatees has increased almost fivefold, from less than 60 to more than 400 individuals. Manatees usually
arrive in small numbers as early as October and leave sometime in April, with the largest population using the spring run during December and January. Decreasing the volume of discharge from Blue Spring threatens wintering manatees by
reducing the size of the warm water refuge. Other threats to manatee survival in Florida are mostly due to human activities, such as operation of boats
and habitat degradation.