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 1976 1974 1972 1970 1968 1966 1964 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/