In total, the seven tributaries listed in Table 3 are estimated to 
contribute an average of 1.95x10 5 kg/yr total nitrogen and 1.35x10^ kg/yr 
total phosphorus to Tampa Bay, reiterating that this does not account for 
substantial nutrient additions to the lower reaches of certain rivers. 
These summed nutrient loading values gives a nitrogen/phosphorus ratio of 
1.6, indicating that tributary inflow to the bay is very phosphorus 
enriched. Much of this is due to the enormous phosphorus load of the 
Alafia River. The ratio of summed nitrogen and phosphorus loadings for 
the other six tributaries is 3.3, which still indicates freshwater rich 
in phosphorus. Fanning and Bell (1985) similarly reported that Tampa Bay 
is considerably enriched in phosphorus, but stated that causes for this 
may be complex, involving leaching of phosphate beds, agricultural 
runoff, point source discharges, etc. 
CONCLUSIONS 
An evaluation of tributary nutrient loading and its effect on bay 
water quality is one of the most important aspects of bay management. 
This chapter has reviewed the streamflow and water quality 
characteristics of tributaries to Tampa and Sarasota Bays but has not 
specifically considered their relationships to bay water quality. That 
topic is discussed in the review of water quality presented later in 
these proceedings. Instead, the emphasis here is that tributaries to 
Tampa and Sarasota Bays must also be managed for their own values, i.e., 
the tidal creek and river habitats upstream of their mouths. 
Collectively, tributaries to these bays include hundreds of miles of low 
and moderate salinity habitats. These tidal habitats are normally 
heavily vegetated by intertidal marshes or mangrove swamps, and are 
important nursing grounds for many of the bays’ most valuable fishery 
species. If these areas are to maintain their biological function, 
various physical and chemical perturbations, such as channel and 
shoreline alterations, freshwater inflow disruptions and nutrient loading 
from point and non-point sources, must be controlled. The Surface Water 
Improvement and Management Act passed by the Florida Legislature 
specifies that Tampa Bay and its tributaries are priorities for 
conservation, management, or restoration. The assessment of Tampa Bay’s 
tidal creeks recently published by the Tampa Bay Regional Planning 
Council (1986) suggested guidelines for improved tributary management. 
Other state and local agencies have sponsored water quality or ecological 
studies on tributaries in the region. With the current level of 
knowledge and commitment, the management of tributaries to Tampa and 
Sarasota Bays should be much improved over previous years. With continued 
population growth, however, management efforts must be persistent if 
environmental qualities are to be preserved or in some cases restored. 
45 
