Orange Lake - Alachua County

Transcription

Orange Lake - Alachua County
Orange Lake
The Lake can be viewed and enjoyed at
The Orange Creek Conservation Area along the
southeastern side of the lake provides
opportunities for hiking, camping, horseback and
bike riding. There is also access to the lake and trails
in the SJRWMD Longleaf Flatwoods Reserve. An
Alachua county boat ramp at Marjorie Kinnan
Rawlings Park near Cross Creek and Marion County
boat ramp at Heagy Burry Park provide access to
the lake and its renowned fishing.
F
Fun Facts
• The lake ranges between 14,7000 to 5,000 acres
depending on rainfall. It averages 5.5 feet in depth and
12 feet is the maximum depth.
• Orange Lake is designated as an Outstanding Florida
Water and worthy of special protection because of
natural attributes.
•Sources of water into the lake are from rainfall and
discharges from Newnans Lake through Prairie Creek,
River Styx andCamps Canal and Lochloosa Lake via Cross
Creek.
•The lake drains through sink holes in the southwest
part of the lake and during high water levels through
Orange Creek, on the southeastern end of the lake.
Orange Creek flows into the Ocklawaha River.
• Land use in the lake’s watershed is predominantly
forests, wetlands and other water bodies. Agriculture
and urban development make up the remaining 16 %.
• Orange Lake is well known as a fishing and bird
watching destination.
Ways you can help!
0
1.25
Miles
2.5
Figure 2. Map of Orange Lake watershed (cream) and
surrounding lakes and tributaries, Alachua County (pink),
and Marion County (teal).
•Dispose of oils and chemicals properly at the
Hazardous Waste Collection Center.
•Properly maintain your septic system.
•Scoop, bag, and trash pet waste.
•Use fertilizers and pesticides sparingly, or not at
all.
•Keep grass clippings out of storm drains, swales,
and ditches put it back on the lawn or bag it.
•Report illicit discharges or dumping to 246-6800.
Water Quality
Lake Level: Water level in Orange Lake is monitored
Nutrients: A Total Maximum Daily Load (TMDL)
1
Total Phosphorus
Geometric mean TP (mg/L)
0.9
0.8
0.7
0.6
0.5
0.4
57
55
53
51
49
47
45
Figure 4. Graph of stage in Orange Lake (1960-2012) data
collected by SJRWMD.
Current Human Impacts:
•The nutrient pollution sources include surface runoff from
the watershed and stream flows into the lake from
Newnans Lake and Lochloosa Lake.
•Historically, there was considerable agriculture around the
lake. Freezes in the mid-1980's devastated the citrus
growing areas and agricultural land use has been slowly
replaced by residential uses.
•Orange Lake is included in Florida’s fish consumption
advisories for mercury.
Chlorophyll a: The TMDL for Orange Lake
0.2
0
a)
2008
2009
2010
2011
Total Nitrogen
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
measures algae by the amount of Chlorophyll a in the
water and sets a goal of 24.1 µg/l. Algal abundance
had greatly exceeded this goal for many years and
reflects the nutrient pollution reaching the lake.
Geometric mean CHL (µg/L)
Geometric mean TN (mg/L)
59
0.3
0.1
b)
61
2012
2010
2008
2006
2004
2002
2000
1998
1996
1994
1992
1990
1988
1986
1984
1982
1980
1978
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1974
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1962
1960
was adopted in 2003 to address nutrient pollution in
Orange Lake. The TMDL was determined for phosphorus in
order to reduce the abundance of algae. The lake was
included in the Orange Creek Basin Management Action
Plan (BMAP) in 2007, which describes nutrient reduction
efforts within the lake’s watershed to reduce pollutant
inputs to the lake. Major sources of phosphorus are
fertilizers in stormwater runoff from residential and
agricultural activities. Orange Lake receives nutrients from
Newnans Lake via River Styx, Prairie Creek and Camps
Canal, and Lochloosa Lake Via Cross Creek.
63
Stage( feet), survey datum
NAVD1988
by the St. Johns Water Management District. The graph to the
right is the recorded stage (water levels) from March 1960 to
April 2012 (Figure 4). Lake levels decrease during periods of
extended drought especially during the 1999-2001 and during
the recent drought.
2008
2009
2010
2011
Figure 3. Graphs of annual geometric mean of a) total
phosphorus (TP) data and b) total nitrogen data (TN)
collected by SJRWMD. A) TMDL goal of 0.031mg/L is
represented by the red line.
200
180
160
140
120
100
80
60
40
20
0
Chlorophyll a
2008
2009
2010
2011
Figure 5. Graph of annual geometric mean of Chlorophyll a
collected by SJRWMD. TMDL established target Chlorophyll a
concentration of Orange Lake is represented by the red line
24.1 µg/L.
To learn more:
•Read the Orange Lake TMDL http://www.dep.state.fl.us/water/tmdl/docs/tmdls/final/gp1/orange_lake_nut_tmdl.pdf.
•Read the Orange Creek BMAP http://www.dep.state.fl.us/water/watersheds/bmap.htm
•For fish consumption advisories visit http://www.doh.state.fl.us/floridafishadvice/
•Visit the St. Johns River Water Management District website at http://www.sjrwmd.com/organge creek/