Water Quality Assessment Report - Florida Department of ...

Chapter 2: Basin Overview
Basin Setting
The Springs Coast Basin encompasses parts of Pasco, Hernando,
Citrus, and Pinellas Counties in west-central Florida. It is bounded on
the west by the Gulf of Mexico and on the east by the Brooksville Ridge,
a sandy remnant of previous higher sea levels, characterized by porous
limestone (karst) geology, with wetlands in low-lying areas and scattered
sinkhole lakes.
The basin covers about 1,052 square miles, or 673,000 acres, not
including an estuarine ecosystem that extends in a nearly unbroken swath
along the entire shoreline. The estuary’s bays, rivers, salt marshes, seagrass
meadows, oyster bars, and tidal fl ats cover approximately another
97,911 acres, or 15 percent of the total basin area. The 6 major rivers in
the basin—Crystal, Homosassa, Chassahowitzka, Weeki Wachee, Anclote,
and Pithlachascotee—their springs, and their associated coastal aquatic
resources are dominant features. Tidal fl uctuations affect all the springs,
except for Weeki Wachee.
The coastline along the basin’s western edge is heavily vegetated, shifting
from saltmarsh-dominated communities in the northern part of the
basin to mangrove-dominated communities in the southern portion. The
low elevation creates fl ooding even during moderate storms. The coast
contains numerous tidal creeks and salt marshes, as well as isolated islands
fringed with mangroves. There are very few natural sandy beaches.
Barrier islands parallel the Gulf coast from southern Pasco County
southward to Tampa Bay. A number of passes, or inlets, connect the Gulf
of Mexico with the estuarine waters between the barrier islands and the
mainland.
The presettlement vegetation in inland areas of the Springs Coast Basin
was dominated by open, fi re-maintained pine forests on sandy uplands and
coastal terraces. Longleaf pine was the dominant tree, replaced by slash
pine in wetter sites and near the coast, and by pond pine in the wettest
inland sites. Wiregrass was the dominant ground cover, particularly in
the longleaf pine forests. Other community types, such as sand pine, oak
scrub, and mesic hammocks, were embedded in the pine forest. In lower
areas, hydric hammocks, swamps, marshes, and other wetland communities
predominated.
Despite a great deal of growth in the last 30 years, Citrus, Hernando,
and Pasco Counties—which are covered by coastal swamps, dense woodlands,
lakes, and pastures—have retained a rural character. However, these
three counties are rapidly changing. Residential and commercial development
has rapidly expanded along the narrow U.S. Highway 19 corridor
Water Quality Assessment Report: Springs Coast
27