The Determination of Minimum Flows for Sulphur Springs, Tampa

DRAFT
Figure 2-14. Return flow structure at Sulphur Springs Pool.
The modification of these diversion facilities allows for the improved management of
flows from Sulphur Springs. Before these modifications were in place, diversions of
spring water to the reservoir at a rate of 20 mgd often caused flows to the spring run to
cease. Now, varying amounts of springflow can be divided between the spring run, the
reservoir, and releases to the lower Hillsborough River below the dam. Beginning in
November 2001, a series of flow experiments were undertaken in which various
quantities of water were diverted from the spring pool to the reservoir or to the base of
the dam. Flow quantities and the response of salinity in the river during these tests are
discussed in later chapters of this report.
2.4 Hydrogeologic and Flow characteristics of Sulphur Springs
2.4.1 Geologic Setting
The hydrogeology of the Sulphur Springs area was described in a United States
Geological Survey Water Resource Investigation report by Stewart and Mills (1984).
The springs are located in an urban area overlain by 30 to 40 ft. (9.1 to 12.2 m) of
surficial sediment composed of sand and clay. Beneath the surficial sediments are a
series of layers of clay, sandy clay, and clayey sand with a combined thickness of
approximately 20 ft. (6.1 m). These sediments are remnants of the Miocene Hawthorn
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