Transcript Hydrology and Water Quality in the Ichetucknee River: What

Historic Water Use and
Groundwater Trends in the
Suwannee River Basin
funded by SJRWMD
For Santa Fe Springs Working Group Meeting May 19, 2011 in O’Leno State Park Florida
Kathleen McKee, M.S.
Research Coordinator
UF Water Institute
Statistical Evaluation Of Long Term
Groundwater Level In Northeastern
Florida And Southern Georgia
• This project involved compilation and
statistical trend analyses of historic hydrologic
data (groundwater levels, rainfall, streamflow)
• in Suwannee River Basin counties
• of Florida and Georgia
• from 1980 to 2007
Also analyzed GW
in northeast FL
counties
SPRINGSHEDS
Ichetucknee and Santa Fe springs
Number of Stations
• 132 groundwater levels (SRWMD, SJRWMD,
USGS)
– Includes NE Florida wells from SJRWMD
– ONLY wells in the Floridan aquifer
• 44 rainfall stations (NCDC)
• 22 streamflow stations (USGS)
Data Compilation
• Data combined into annual calendar year time series for the
period 1980 to 2007
• Annual average time series were used for groundwater &
streamflow
– GWL: 20 years of data with at least 2 measures / year
– Streamflow: 10 years of daily averages
• Total annual inches time series were used for rainfall
•
Rain: 20 years of data with at least 8 monthly total / year
• Additional groundwater level data in northeast Florida and
southeast Georgia were added (request from SJRWMD).
Statistical Trends
• LOWESS – graphical evaluation to determine if
monotonic or piecewise (Cleveland, 1981)
• Trend detections (for both monotonic and
piecewise) were conducted using Mann-Kendall
test (Hamed, 2008; Hamed and Rao, 1998)
• Confid levels:
–
–
–
–
> 95%, very certain (there is a trend) (p-value < 0.05)
> 90%, probably trending (p-value < 0.10)
> 80%, possible (p-value < 0.20)
< 80%, no trend detected
Monotonic
Very certain downward
Slope = 1.38 ft/yr
p-value = 0.014
Monotonic
No Trend Detected
p-value = 0.175
slope = -0.099 ft/yr
Piecewise
1st section:
Very certain upward
p-value = 0.014
slope = 1.38 ft/yr
2nd section
No Trend Detected
p-value = 0.161
slope = 0.478 ft/yr
7 USGS - GW level
52 SRWMD – GW level
73 SJRWMD, USGS Groundwater level
Upward
trend
22 NCDC – rainfall
No trends
22 NCDC - rainfall
1 trending down Dixie
2 rain stations
NO trend
P-value = 0.22
Trend
P-value = 0.01
9 USGS – streamflow
No trends
13 USGS – stream flow
No trends
GW Trend Results
Significant trends (conf level > 85%):
• 12 wells in SRWMD
• 5 USGS wells in Georgia
• 28 SJRWMD wells
All were downward except one in St. Johns
County.
Counties with Signif GW reduction
• Georgia
– Worth, Tift, Cook
• Florida (SRWMD)
– Baker, Bradford, Lafayette, Union
Water Use data estimation
• from 1980 to 2007 in millions of gallons per year.
• Agric from USGS = Agricultural calculated by USGS every 5 years
using estimated irrigated crop acreage multiplied by a use
coefficient from selected crop irrigation models;
• Agric we calculated = estimated crops reported by NASS *
recommended irrigation for that crop
• DomSelfSup = Domestic Self-Supply (USGS calculates using
statewide per capita water use rate * population not using public
supply)¥;
• PubSupp = Public Supply (from monthly permittee reporting);
• Comm Ind Pow = Industrial/commercial/mining/power (from
monthly permittee reporting).
7 USGS - GW level
Water Use estimation data
Water Use estimation data
Tift
County
Georgia
Water Use estimation data
Cook
County
Georgia
52 SRWMD – GW level
Water Use estimation data
Baker
County
Florida
Water Use estimation data
Bradford
County
Florida
Water Use estimation data
Lafayette
County
Florida
Water Use estimation data
Union
County
Florida
Water use data
5 year reports done by Rich Marella at USGS:
http://pubs.usgs.gov/sir/2009/5125/
Water Use: important & not easy!
Here is what Agriculture estimates look like
when we try
to do them:
Water Use: important & not easy!
Here is what Agriculture estimates look like
when we try
to do them:
Thank you!
Kathleen McKee
[email protected]
Reports online:
http://www.sjrwmd.com/technicalreports/pdfs/SP/SJ2010SP12.pdf
http://www.sjrwmd.com/technicalreports/pdfs/SP/SJ2010SP11.pdf