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Dr. Knight warns Gilchrist County has water quality issues

Dr. Robert Knight, executive director of the Howard T. Odum Florida Springs Institute, spoke to the Gilchrist County Economic Development Advisory Committee (GCEDAC) on Monday afternoon, December 8, 2014 at the Gilchrist County Library.

Dr. Knight made an extensive presentation of historical statistics regarding the Suwannee River Basin’s water resources and explained current trends affecting water quantities and quality.

Florida has experienced a wet climate for the last 8,000 years.  The greater Suwannee River Valley represents 27 percent of total historical Floridan Aquifer discharge. This aquifer is a repository of potable water created from rainwater seeping down through the porous underground limestone layers.  Underneath the fresh water aquifer layer is another layer of brackish or salt water. For each one-foot reduction in the freshwater aquifer layer there is a 40-foot rise in the underlying salt water levels.

Much of Gilchrist County’s land has sandy soils that allow anything placed on or applied to the surface soil to ultimately go down into the freshwater aquifer. Waccasassa Flats has clay soil so the rainwater mostly stays on the land surface, creating lakes, streams, and wetlands. Up to 10-15 inches per year of rainwater is added to the aquifer in sandy soils, but only about one inch gets added in clay soils.

For most of Florida’s history, rainwater replenished (or recharged) the aquifer, and springs and river flows were how the overflow of water that the aquifer couldn’t hold came out of the aquifer (discharged) to achieve an overall steady state in underground water levels. This sustained the water table.

Once human activities started removing large quantities of water from the aquifer, spring and river flows started to decrease. Many springs have dried up or now have reduced flows.

For example, Fanning Springs has been reduced from a First Magnitude Spring to a Second Magnitude Spring. The Santa Fe River (essentially a large spring flow) has experienced over a 40 percent decrease in its historical flow.  A recent UF study estimates that springs produce $85-140 million a year in economic benefit for our area.

Gilchrist County uses a relatively small amount of aquifer fresh water, estimated at 9 million gallons a day by the U.S. Geological Survey in 2010.  However, all of North Florida, particularly urban and suburban areas (Jacksonville, Gainesville, the East Coast) use large amounts of groundwater, such that 1,900 square miles of the Suwannee River Basin aquifer freshwater is now shifted (sipped like liquid through a straw) to the East and North according to the U.S. Geological Survey.

Dr. Knight has concluded that aquifer fresh water is being over pumped out the ground, many times for uses other than for drinking and cooking purposes. Too many water permits for too many gallons have already been issued by the State. Watering lawns and golf courses is not the best use of this precious clean water. Moreover, water, a public good in Florida, is being essentially given away and “banked” by private interests. He suggests that water needs to be subject to an “Aquifer Protection Fee” to encourage conservation and proper use, and to produce funds to develop alternative water sources.

Gilchrist County has a much more serious water quality problem according to Dr. Knight.

The most serious concern is the accumulation of nitrates in the water. US EPA sets a 10ppm per liter ceiling of nitrates in the water for human use. This standard was set initially in the 1970s and is periodically reviewed to update for new scientific findings.  Some nitrates occur naturally, but others are created by human activities; in particular in fertilizers, and animal and human waste. These nitrates reach our drinking water as rainwater carries them down into the aquifer.

While wetlands such as the Waccasassa Flats tend to “scrub” nitrates out of surface water before it reaches the aquifer, where the soils are sandy the nitrates quickly reach the aquifer. Current Florida spring standards set by Florida DEP is .35 parts per million of nitrates because springs aquatic animal and plant life is more sensitive to its effects than humans.

Locally, row crops, dairies and septic tanks produce nitrates that are negatively affecting water quality.

For example, Wendy Graham, Director of UF IFAS’s Water Institute, has performed research that indicates for each acre of dairy farming, 80-120 acres should remain “unfarmed”.

Recent observations and calculations show nitrates in the Santa Fe River are 10 times historical levels (increasing from 80 tons to 800 tons of nitrate-nitrogen per year) and that the Suwannee River carried about a 7,600 tons of nitrate-nitrogen to the Gulf last year, most of which was derived from farming and ranching.

Dr. Knight made the following observations.

•  Private wells near dairies need

to be monitored regularly

for nitrate levels, and for

those exceeding EPA’s 10ppm

per liter limit, the water should

not be used for drinking and

cooking.

•   More rainwater and surface

water needs to be used for

irrigation, with the objective

of reducing groundwater

pumping by 50 percent.

•   Nitrate levels, for springs

protection, need to be

reduced by 80-90 percent from

current levels.

•  Confined feeding areas for

livestock can be less impactful

on aquifer quality than

field acreage if a high level of

nitrogen removal is made

through advanced wastewater

treatment.

•   Local interests need to

consider approaching CDC or

NIH regarding cancer

epidemiological studies for

rural North Central Florida to

determine if there is a link

between elevated cancer rates

and widespread elevated

nitrate concentrations in

drinking water.

The Gilchrist County Economic Development Advisory Committee meets monthly and arranges for speakers on topics pertinent to local economic development and county’s comprehensive land use planning.

By Diane Clifton