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Innovative Solution Springs Life to Wetlands A dual purpose flood reduction and wetland restoration project
Cynthia Grizzle PWS, CFM
OverviewHISTORIC IMPACTS
PROJECT OBJECTIVES
EVIDENCE OF SUCCESS
Location
Background
Wholesale Water Supplier
Non-Profit, Special District of the State of Florida created to plan, develop and deliver a high-quality drinking water supply and protect water supply sources
Funded through sale of water to member governments (Hillsborough County, Paso County, Pinellas County, New Port Richey, St. Petersburg and Tampa) who all share the cost of operation
Background
The RegulatorEstablished as a flood protection agency, its responsibilities have grown to include managing the water supply, protecting water quality, and preserving natural systems that serve important water-related functions
Issue water use permits to ensure withdrawals from water bodies will not harm existing users, the water resources, or the environment
Background
1) Reduce downstream flood flows
2) Maximize use of low and flood-prone lands for flood-water storage
3) Maximize well field production
Purpose of the Property
Background
Groundwater Pumping
Impacts
Reduced Water LevelsHistorically high rates of pumping reduced water levels
Tampa Bay Water diversified water sources and reduced pumping
Candidate Mitigation Sites Evaluation Study 2000
Identified Sites Not Expected to Fully Recover Following Pumpage Reductions
Impacts
Floodplain Encroachment
Impacts
Existing Flow Patterns
Impacts
35.2644.39
50.84
75.58
63.91
0
10
20
30
40
50
60
70
80
2000 2001 2002 2003 2004
Water Year (October through September)
Tota
l Rai
nfal
l (In
ches
) Cypress Creek Wellfield Average Yearly Total1976 through 2004
51 Inches
Above Normal Rainfall and Residential Flooding in 1997/1998; 2003; & 2004
Impacts
Impacts
Timeline1) A Series of Community Meetings with SWFWMD, Tampa Bay Water, and Pasco County Staff Occur in 2003 and 2004
2) SWFWMD Performs a Preliminary Feasibility Study (February 2004)
-Assessed options to redirect floodwater onto the wellfield
3) Tampa Bay Water Recognizes the Potential for SWFWMD’s Flood Mitigation Project to act as Wetland Restoration
-Initiates the CCWF Surface Water Management Project (June 2004)
Objectives
Four Project Objectives
Improve flow through Dye’s Crossing by replacing existing structures
Utilize existing storage south of Dye’s Crossing
Control surface water flows leaving the wellfield
Redistribute water to target wetlands via culvert connections and open ditches
Objectives
Stages Feasibility -2004/2005 Design and Permitting – 2005/2006 Construction - 2007 Monitoring- Ongoing
Objectives
Redirect Historic Flow
Weir Elevation 68.29 ftNorth of Dye’s Crossing Rd
6, 18” Diameter PipesSouth of Dye’s Crossing Rd
Improve Flow Through Dye’s Crossing
Objectives
Weir Bottom Elevation 68.29 ftRoad Elevation ~71.00 ft
4 (4 ft x 8 ft) Type H Structures with Double 30” Diameter Pipes (North of Dye’s Crossing)
8 - Tideflex Backflow Preventers (South of Dye’s Crossing)
Dye’s Crossing Today
Objectives
274 ft Long Concrete Weir at Main Flow Channel along Berm A1a – West End
Utilize Storage South of Dye’s Crossing
Objectives
30” Diameter Low Flow Pipe (Invert Elevation 65.0 ft)
Top of Weir Elevation 70.0 ft
18” Diameter High Flow Pipe Elevation 67.93 ft
Control Surface Water Leaving the Wellfield
Objectives
Weir Height ~ 5 feet
Down Stream
Functioning As Designed
Objectives
Redistribute Water to Target Wetlands
Objectives B2 Ditch Before Construction
B2 Ditch During Construction
B2 Ditch Following Construction
Key Project Achievements Minimize impacts to
natural areas and wildlife during construction
Reduce flooding conditions in adjacent residential areas
Improve wetland hydrology and functions in the target wetlands
Success
B2 Ditch Following Construction (Pop Off Elevation 68.0 ft) – West of Ten Cent Road
Functioning As Designed
Success
Reduce Impacts to Natural Areas
Construct in previously disturbed areas
Protect gopher tortoises and their burrows
Shorten pipe lengths to reduce impacts and maintain aesthetics
Reduce the construction footprint
Construct in Disturbed Areas
Success
Restrict Construction Footprint
Success
Minimized Impacts to Undisturbed Areas
Success
Shorten Pipe Lengths to Lessen Impacts
Success
Protect Gopher Tortoises
Success
Reduce Flooding Conditions Offsite
Success
Improve Wetland Hydrology
Success
Depth of Wetland Inundation- W43
Success
Depth of Wetland Inundation – W16
Success
Duration of Wetland Inundation Wetlands with
Hydroperiods WY2015 – 26/26 WY2014 - 23/26 WY2013 - 24/26 Wy2012 - 24/26 WY2011 -18/26 WY2010 - 8/26 WY2009 - 2/26 WY2008 - 0/26 WY2007 - 0/26
Success
Vegetative Recovery
Pines in the wetland are stressed and/or dead
Success
Project Summary Nearly 2 miles of Berm Constructed
Retains water on the wellfield to allow for storage and aquifer recharge
4,000 feet of Ditches Installed Increased hydrologic connectivity
has improved hydroperiod and stage in several target wetlands
Construction Footprint was Reduced by Half
Project Ended $300,000 Under Budget
Florida Chapter of APWA 2010 Consultant of the Year
The Next Phase
Thank You
