This project had three objectives: 1) Reduce downstream flood flows, 2) Maximize use of low-lying lands for flood water storage, and 3) Maximize well field production. It achieved these objectives through constructing berms and ditches to redirect floodwater onto a wellfield for storage and aquifer recharge, improving wetland hydrology and reducing offsite flooding. Monitoring showed improved wetland hydroperiods, vegetative recovery in wetlands, and the project ended under budget.

1. Innovative Solution Springs Life to Wetlands
A dual purpose flood reduction and wetland restoration project
Cynthia Grizzle PWS, CFM

2. Overview
HISTORIC IMPACTS
PROJECT OBJECTIVES
EVIDENCE OF SUCCESS

3. Location
Background

4. Owners
Background

5. 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

6. The Regulator
Established 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

7. 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

8. Groundwater Pumping
Impacts

9. Reduced Water Levels
Historically 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

10. Floodplain Encroachment
Impacts

11. Existing Flow Patterns
Impacts

12. 35.26
44.39
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)
TotalRainfall(Inches)
Cypress Creek Wellfield
Average Yearly Total
1976 through 2004
51 Inches
Above Normal Rainfall and Residential
Flooding in 1997/1998; 2003; & 2004
Impacts

13. Impacts

14. 1) 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

15.  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

16. Stages
 Feasibility -2004/2005
 Design and Permitting – 2005/2006
 Construction - 2007
 Monitoring- Ongoing
Objectives

18. Weir Elevation 68.29 ft
North of Dye’s Crossing Rd
6, 18” Diameter Pipes
South of Dye’s Crossing Rd
Improve Flow Through Dye’s Crossing
Objectives

19. Weir Bottom Elevation 68.29 ft
Road Elevation ~71.00 ft
4 (4 ft x 8 ft) Type H Structures with Double 30”
Diameter Pipes (North of Dye’s Crossing)

21. 8 - Tideflex Backflow Preventers
(South of Dye’s Crossing)

23. Dye’s Crossing Today
Objectives

24. 274 ft Long Concrete Weir at Main Flow
Channel along Berm A1a – West End
Utilize Storage South of Dye’s Crossing
Objectives

25. 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

26. Weir Height ~ 5 feet

27. Down Stream

28. Functioning As Designed
Objectives

29. Redistribute Water to Target Wetlands
Objectives
B2 Ditch Before Construction

30. B2 Ditch During Construction

31. B2 Ditch Following Construction

32. 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

33. B2 Ditch Following Construction
(Pop Off Elevation 68.0 ft)
– West of Ten Cent Road
Functioning As Designed
Success

34. 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

35. Construct in Disturbed Areas
Success

36. Restrict Construction Footprint
Success

37. Minimized Impacts to Undisturbed
Areas
Success

38. Shorten Pipe Lengths to Lessen
Impacts
Success

39. Protect Gopher Tortoises
Success

40. Reduce Flooding Conditions Offsite
Success

41. Improve Wetland Hydrology
Success

42. Depth of Wetland Inundation- W43
Success

43. Depth of Wetland Inundation – W16
Success

44. 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

45. Vegetative Recovery
Pines in the
wetland are
stressed
and/or dead
Success

46.  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

47. The Next Phase

48. Thank You