Scientific Investigations Report 20095046
Hydrologic, physicochemical, and aquatic community data were collected and compiled by the U.S. Geological Survey for selected springs within the St. Johns River Water Management District from January 2004 to October 2007. Nine springs were included in this study: Alexander, Apopka, Bugg, De Leon, Gemini, Green, Rock, Silver Glen, and Wekiwa. Urban lands increased in Alexander, Apopka, De Leon, Gemini, Green, and Wekiwa springsheds between 1973 and 2004, accompanied by a loss of forested and/or agricultural lands in most springsheds. Forested cover increased and open surface waters and wetlands decreased in the Bugg and Rock springsheds. Although rainfall did not change significantly over time in each springshed, spring discharge decreased significantly in De Leon, Fern Hammock, Rock, Silver, and Wekiwa Springs. Nitrate concentrations increased significantly with time in Apopka, Fern Hammock, Gemini Springs run, and Juniper Springs, and decreased significantly in Alexander Spring, Bugg Spring run, Rock Springs, and Wekiwa Springs. Phosphorus increased significantly with time in Juniper Springs and decreased significantly in Apopka, De Leon, Rock, Silver Glen, and Wekiwa Springs. Benthic macroinvertebrate communities ranged from relatively low diversity assemblages (Green Spring) to assemblages with high taxonomic richness, diversity, and dominance (Rock and De Leon Springs). Shannon-Wiener diversity index averages among samples pooled by spring were lowest for Apopka Spring and greatest for Rock, Bugg, and Silver Glen Springs. Mean Stream Condition Index for pooled samples per spring was lowest for De Leon and Gemini Springs and highest for Rock and Wekiwa Springs. Mean percentages of very tolerant taxa were lowest for Alexander Spring and highest for Bugg and Green Springs. Fish community richness was lowest for Green Spring, and greatest for Alexander Spring run and Silver Glen Springs. Forty five fish species representing 35 genera and 23 families were collected or observed from all springs in this study. Samples were dominated by centrarchids, cyprinids, fundulids, atherinopsids, and poeciliids.
Posted July 2009
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Walsh, S.J., Knowles, Leel Jr., Katz, B.G., and Strom, D.G., 2009, Hydrology, Water Quality, and Aquatic Communities of Selected Springs in the St. Johns River Water Management District, Florida: U.S. Geological Survey Scientific Investigations Report 2009-5046, 116 p.
Purpose and Scope
Methods of Investigation
Delineation of Springsheds
Land Use Data Compilation
Hydrologic Data Compilation
Collection and Analysis of Spring Water
Age Dating of Spring Water
Aquatic Community Data Collection and Analysis
Hydrology, Water Quality, and Aquatic Communities of Selected Springs
De Leon Spring
Fern Hammock Springs
Silver Springs Group
Silver Glen Springs
Land-Use Changes among Springsheds
Trends in Spring Discharge and Rainfall
Comparison of Aquatic Communities
Appendix 1: Macroinvertebrate taxa collected by dip net and petite ponar dredge from selected springs in the St. Johns River drainage, 2004-07.
Appendix 2: Fishes species recorded from selected springs sampled in the St. Johns River drainage, 2004-07.
Appendix 3: Physicochemical data for springs on dates that benthic macroinvertebrate samples were collected in 2004-07.
Appendix 4: Concentrations of organic wastewater compounds detected in water samples from selected springs in the St. Johns River drainage.
Appendix 5: Concentrations of pesticides analyzed in water samples from selected springs in the St. Johns River drainage, 2004-07.