Anclote, and Crystal Rivers), the Hillsborough River Basin, the Alafia River 

 Basin, and the area between Myakka River and the Alafia River. The major 

 metropolitan areas are Tampa, St. Petersburg, Clearwater, Sarasota, and 

 Bradenton. Each of the river basins is described in the following subsec- 

 tions. 



Pitchlachascotee, Anclote, and Crystal River Basins . The Pitchlachascotee 

 River originates in Hernando County, Florida, and flows about 41 mi southwest 

 to the Gulf of Mexico at New Port Rickey. About 15% of the average flow of 

 the river is supplied by the Floridian aquifer. Land use is primarily agri- 

 cultural, and New Port Rickey is the only urban area. Violations of State 

 water quality standards for dissolved oxygen and pH are common. Data indicate 

 no overall temporal trend in water quality. Within the Pitchlachascotee 

 drainage, water quality is usually good or very good. The Anclote River orig- 

 inates in south-central Pasco County and flows westward approximately 27.5 mi 

 to the Gulf of Mexico. The major land use in this area is agriculture. Water 

 quality standards of pH and DO concentrations in the south branch often are 

 violated, and total alkalinity, pH, and mercury concentrations occasionally 

 fall below State standards. Macroinvertebrate diversity at the mouth of the 

 Anclote River is reasonably good. The Crystal River originates from a group 

 of springs at Kings Bay and flows approximately 6 mi to the Gulf of Mexico. 

 Little change in water quality of the Crystal River has been reported; gener- 

 ally, the water quality is ^ery good. 



Hillsborough River Basin . The Hillsborough River flows southwesterly for 

 about 55 mi from the Green Swamp area in Pasco County to Hillsborough Bay. 

 The principle tributaries are Trout Creek, Blackwater Creek, and Six Mile 

 Creek. The Hillsborough River provides the potable water supply for Tampa. 

 The primary sources of pollution are urban and agriculture runoff, domestic 

 sewage (8 Mgal/d) and industrial discharges (11.5 Mgal/d), primarily from 

 citrus processing plants. 



Surface runoff and domestic sewage are the major pollution sources in the 

 southern stretch of the river. Moderately high levels of TKN occur near the 

 headwaters of the Hillsborough River (0.915 mg/1). Total phosphorus values 

 are high throughout the river (0.320 to 0.068 mg/1). Itchepachesassa Creek, a 

 tributary to Blackwater Creek, receives wastes from several citrus industries. 

 The high phosphorus and nitrate-nitrite levels may be caused by the various 

 industrial discharges into Blackwater Creek. Mean DO concentrations are very 

 low (0.32 mg/1) near the headwaters, but increase to 6.5 mg/1 in mid-reaches. 

 DO concentrations below State water quality criteria are frequently reported 

 throughout the river. This may in part be due to natural Green Swamp drainage 

 and tidal influences. 



Concentrations of cadmium, lead, and mercury above the State water qual- 

 ity standards have been detected in the Hillsborough River near Zephyrhills, 

 in Trout Creek, and in Tampa urban area. Levels of fecal coliform bacteria 

 are high near Blackwater Creek (961/100 ml ) and extremely high (5,480/100 ml ) 

 near Tampa. These concentrations are 4 to 27 times greater than the 200/100 

 ml State standard for Class I Potable water supplies and are caused mostly by 

 domestic sewage. Macroinvertebrate diversity is good, especially in the up- 

 stream undeveloped areas. Average concentrations of TKN and total phosphorus 

 have declined in recent decades whereas substantial increases in nitrate- 

 nitrite concentrations and fecal coliform counts have increased. No overall 



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