Sweetwater Creek Watershed Mgmt. Plan 2007 Update--Part 2

WATER SUPPLY
9.4.2 Impacts Due to Water Withdrawals
The literature describing the effects of groundwater withdrawal on wetland hydroperiods and lake
stages dates to 1971. Since that time, the nature of the impacts to wetlands has been documented
in wetlands both in and around major wellfields (Rochow, 1998). Generally, symptoms of wetland
health decline (e.g., replacement of aquatic plant species by upland species, tree-fall, soil
subsidence, loss of wetland-dependent wildlife) have occurred in the vicinity of large-scale
groundwater withdrawals (e.g., Section 21, Cosme, Northwest Regional, and Eldridge – Wilde
Wellfields). As a Water Use Permit (WUP) condition, permit holders have been required to monitor
water levels and ecological indicators of wetland viability, and annual reports have been prepared
describing wetland hydrobiological conditions since the mid-1970s. The link has been made
between groundwater withdrawals and reduced hydroperiod in area wetlands. Under the NTB II
project, the SWFWMD has established many more wetland monitoring sites, and recovery strategy
has been developed.
The recovery strategy involves:
• District and Tampa Bay Water (TBW) water level monitoring
• District and TBW biologic monitoring (WAPs)
• TBW annual assessment of wellfields (annual reports)
• District Minimum Flows and Levels (MFL) monitoring
• Environmental Monitoring Plan (EMP) referrals to the Operations Plan
During the first several years of pumpage from the three wellfields in the project area, wetlands
within the wellfield’s zone of influence exhibited signs of wetland health decline including the
replacement of wetland vegetation with upland species. These ecological changes were attributed
to sustained groundwater production as well as below normal rainfall conditions. From about 1986
to 1993, overall annual pumpage rates for the wellfields were reduced by nearly 40% compared to
the original production period. Recent pumpage data from the area’s three wellfields, however,
indicates that the production in the wellfields has increased but not significantly.
Several management strategies have been proposed/undertaken to minimize the impacts due to
water withdrawals, which include the following:
• Development of operation and management plans to minimize environmental impacts for all
permitted water users
• Implementation of projects associated with the NTBWUCA
• Investigation for alternative sources of water
• Development and implementation of aggressive water conservation and water reuse
programs
• Continuation of cooperative funding to encourage development of alternative water sources
• Continuation of regulatory requirements/incentives for alternative water sources
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Sweetwater Creek Watershed Management Plan