Land use in the basin is primarily agricultural (38.9%) and barren land 

 (8.9%). The latter reflects the 1 imerock mining activities in the Lower 

 Withlacoochee River Basin. Surface runoff and industrial and domestic sewage 

 are the primary sources of pollution. Major urban areas are Inverness, 

 Brooksville, and Dade City. The acid swamp drainage that fontis the headwaters 

 of the Withlacoochee influences downstream water quality. Average DO concen- 

 trations are somewhat low (4.3 mg/1 ) near the headwaters, but increase only 

 slightly downstream (5.6 mg/1). Measurements below the State standard of 5.0 

 mg/1 have been frequently reported throughout the river. Average pH values in 

 recent years have increased from 4.7 to 7.5. Heavy metal concentrations of 

 cadmium, lead, and aluminum in excess of State water quality standards have 

 been detected. Mean fecal coliform levels are low throughout the Withlacoochee 

 River and no consistent temporal trends in water quality are apparent. In 

 general, the water quality in the Withlacoochee River Basin is good. 



WATER QUALITY IN ESTUARIES (CLASS II, III) 



Saltwater (brackish) Class III waters are suitable for saltwater species 

 of aquatic life and for water-related recreation. Class II is designated 

 solely for shellfish propagation. The acceptable limits of Class II often is 

 far more restrictive than Class III because of the filter-feeding nature of 

 shellfish and threat to public health. In polluted areas, shellfish consume 

 pollutants, some of which accumulate in their body tissues to levels that can 

 endanger human health if consumed (Lynch 1981). 



Water quality, based on concentrations of nitrates-nitrites, ammonia, 

 phosphorus, fecal coliform bacteria, and nutrients, and on benthic diversity, 

 generally has been good in Southwest Florida estuaries. The major coastal 

 estuaries in the network of stations monitored in 1977-79 were Tampa Bay, 

 Charlotte Harbor, and Florida Bay areas. Estuaries in central Florida (Tampa 

 Bay) generally had average water quality, whereas water quality in Charlotte 

 Harbor generally was above average; consequently, neither is an immediate 

 threat to public health or the aquatic environment. Pennekanp Park had the 

 lowest total organic carbon (average 3.5 mg/1) and chlorophyll A (less than 

 110 micrograms per liter). It also had the highest diversity in the State, 

 averaging 5.19. 



Dissolved oxygen concentrations were good in all estuaries, ranging from 

 6.0 mg/1 in the Peace River estuary to 7.5 mg/1 in Hillsborough Bay. Bio- 

 logical oxygen demand (BOD) also was high, up to 4.0 mg/1 in Hillsborough Bay. 

 Nutrient concentrations were generally low in most estuaries. The exceptions 

 are given later. Hillsborough Bay had the highest ammonia concentration in 

 the State (0.28 mg/1) whereas other estuaries averaged less than 0.13 mg/1. 

 High phosphorus concentrations were evident in Hillsborough Bay (1.24 mg/1). 

 Middle Tampa Bay (0.78 mg/1). Colifomi counts generally followed trends 

 similar to phosphorus. The four stations in Hillsborough and Tampa Bays had 

 higher fecal and total coliform counts than most other stations in Florida 

 estuaries. Hillsborough Bay had the highest average fecal and total coliform 

 counts (490/100 ml and 3,250/100 ml, respectively) in Southwest Florida. 



Turbidity was low (4 JTU's) in Southwest Florida estuaries and total 

 organic carbon and chlorophyll A concentrations generally were high. Organic 

 carbon ranged from 6.7 to 12.0 mg/1. Hillsborough Bay had the highest average 



266 



