Transcript Econfina Creek Springs

Jackson Blue Spring
Overview and Basin Delineation
Kris Barrios, NWFWMD
Jackson Blue Spring Basin Working Group
September 21, 2006
Floridan Aquifer Springs in the
Dougherty Karst Region
Spring inventories available at:
www.nwfwmd.state.fl.us/pubsdata/techpubs.html
Jackson Blue Spring - Discharge
• Average Measurement of 152 cfs (cubic feet per
second)
• Measurements concentrated from 2001 to present
Jackson Blue Spring Discharge
350
discharge (cfs)
300
250
200
150
100
50
0
1/1/1928
12/31/1942
12/31/1957
12/31/1972
date
1/1/1988
12/31/2002
Jackson Blue Spring - Nitrate
• Clear historical increasing trend
• Present values range from 3.0 to 3.5 mg/L
4.00
3.50
concentration (mg/L)
3.00
2.50
2.00
1.50
1.00
0.50
0.00
3/25/1960
3/25/1970
3/25/1990
3/25/1980
date
3/25/2000
Florida Springs Initiative 2001-2002
Two tasks focused on Jackson Blue Spring
• Ground Water Basin Delineation
• Land Use Analysis
Potentiometric Surface
• A model of the surface of the Floridan Aquifer water table based
on elevations measured in Floridan Aquifer wells and springs
1991 Floridan Aquifer
Potentiometric Surface
Potentiometric Surface
• Water movement is from areas of high potential to areas of low
potential…..in other words “downhill”
Spring Ground Water Basin
• The area generated from a potentiometric surface where the
ground water flow path leads to a spring
Jackson Blue Spring Basin
(Chelette, et. al. 2002)
Jackson Blue Spring Basin Land Use
• Mapped from GIS land use coverages made from 1994-1995
aerial photographs
0.14
0.04 0.10
0.02
0.15
0.25
1.45
3.06
Barren Land
Institutional
Commercial & Services
Trans,Com&Util
50.46
44.33
Industrial
Water
Wetlands
Residential
Upland Forests
Agriculture
Origin of Jackson Blue Spring Nutrients
• Brian Katz (USGS) performed an analysis of nitrogen isotope data
collected from Jackson Blue Spring in October 2001.
The low d15N result for
Jackson Blue Spring indicates
inorganic fertilizer as the
source of the elevated N
concentration
Age Dating Spring Water
•
Also conducted by Katz in 2001….best determined by the 3H/3He ratio
Analysis resulted in a mean
recharge year of 1984……17 years
Estimated Fertilizer Application
4.00
3000
3.50
3.00
2500
2.50
2000
2.00
1500
1.50
1000
1.00
500
0.50
0
0.00
year
Nitrate Concentration (mg/L)
3500
19
72
19
74
19
76
19
78
19
80
19
82
19
84
19
86
19
88
19
90
19
92
19
94
19
96
19
98
20
00
20
02
20
04
Nitrogen Application (Tons)
• Calculated from reported fertilizer sales in Jackson County
Nitrogen Application (Tons)
Nitrate Concentration (mg/L)
Basin Nitrate Concentrations
•
Samples collected and analyzed Fall 2004 (Barrios and DeFosset, 2005)
Indicates present water quality in basin
Assuming the samples do represent
conditions within the entire basin, the
average Nitrate concentration is
currently 2.7 mg/L
Primary Contribution Area
• Based on statistical analysis of water chemistry
Study in Progress
•
Sample collection from Jackson Blue Spring and seven additional spring vents in
Merritts Mill Pond.
•
Refinement of Floridan Aquifer potentiometric surface with surveyed elevations –
improvement from 10-foot to 1-foot resolution.
•
Installation of continuous velocity meter within the Jackson Blue Spring conduit.
•
Land use comparison between 2004-2005 data and 1994-1995 data.
Nitrate values in other springs:
Hays Spring – 3.1 mg/L
Baltzell Spring – 2.5 mg/L
Shangri-La Spring 3.4 mg/L
Double Spring – 0.95 mg/L
Gadsden Spring – 0.84 mg/L
Mill Pond Spring – 0.97 mg/L
Springboard Spring – 0.84 mg/L
(FGS Bulletin 66)