Table 1. Land use distribution within Tampa Bay tributary watershed 
(1983). (From Hartigan 1984) 
Land Use % Total Area Subtotal 
Forest 
16.6 
16.6 
Cropland/other rural 
21.3 
Pasture 
38.9 
60.2 
Urban residential/other 
16.2 
Urban commercial/industrial 
7.0 
23.2 
100.0 
100.0 
Such land use distribution can be translated into geographically 
specific areas that produce modifications to the quantity and quality of 
runoff (Figure 5). Areas of generally high, medium and low concentration 
of urbanization directly relate to areas which produce high, medium, and 
low volumes of runoff and poor, moderate and good (relatively) water 
quality from runoff. 
URBAN STORMWATER CHARACTERISTICS 
It is important to describe the characteristics of the stormwater 
collection systems in the Tampa and Sarasota Bay areas in order to fully 
understand the quantity and quality of resulting runoff. The Tampa and 
Sarasota Bay areas are fully served by separate storm and sanitary sewer 
systems. Unlike many areas in the northeast and other parts of the 
country which have combined systems, this area is fortunate in that most 
if not all sanitary sewage is collected, treated, and then discharged in 
dedicated systems on a continuous basis, whereas stormwater is collected 
in separate systems and may or may not be treated. The most heavily 
urbanized areas shown in Figure 5 are serviced by closed storm sewer 
systems which consist of inlets, pipes, collector systems and major 
outfalls. Some major ditches and outfall canals exist in the heavily 
Urbanized areas. In the light urbanized areas or areas of moderate 
urbanization, stormwater collection is accomplished more through 
neighborhood ditches, rural roadway sections and canals. 
The Tampa Bay area has one of the highest rates of runoff in the 
entire gulf area. The density of development in Pinellas County produces 
runoff intensities comparable only to New Orleans and Houston (Figure 6). 
Combining densely populated, established areas and rapidly urbanizing 
surrounding areas results in the highest runoff volumes of any 
metropolitan area (multiple counties) tributary to the Gulf of Mexico 
(National Ocean Service, 1985). Needless to say, such level of 
urbanization and runoff volume results in local flooding problems. It 
would be a fair assessment to say that the primary focus of local 
attention at the City, County, and State level is on the quantity of 
runoff and flooding, rather than water quality under existing conditions 
with current federal funding and local/state regulatory mandates 
(treatment for new construction only). 
151 
