Abstract ........................................................ 1
Introduction .................................................... 3
Purpose and Scope ............................................ 5
Description of Study Area .................................... 7
Rainfall Patterns and Regional Ground-Water Withdrawals ...... 7
Description of Study Design .................................. 9
Acknowledgments ............................................. 11
Wetland Hydrogeologic Setting .................................. 13
Regional Hydrogeology ....................................... 13
Hydrogeologic Methods ....................................... 15
Basin Stratigraphy .......................................... 21
Sub-Wetland Stratigraphy ................................. 21
Radium-226 ............................................... 32
Evidence of Karst Features in Wetland Basins ............. 35
Ground-Water Flow Patterns in Wetland Basins ................ 37
Overview of Wetland Hydrogeologic Settings .................. 43
Wetland Water Budgets .......................................... 45
Methods of Computation ...................................... 48
Rainfall and Evapotranspiration .......................... 48
Wetland Stage, Volume, and Area .......................... 48
Wetland Leakage ............................................. 49
Effect of Downward Head Differences on Wetland Leakage ...... 50
Effect of Hydraulic Conductivity on Wetland Leakage ......... 52
Case Studies of Wetland Leakage ............................. 53
Duck Pond Augmented Marsh ................................ 53
S-63 Augmented Cypress ................................... 54
W-5 Augmented Cypress .................................... 56
Runoff to Wetlands .......................................... 59
Overview of Wetland Water Budgets ........................... 60
Wetland Water Quality and Geochemistry of Wetland Basins ....... 63
Water-Quality and Geochemical Methods ....................... 63
Water-Quality Constituents .................................. 64
Field Properties and Major Ions .......................... 64
Nutrients and Dissolved Organic Carbon ................... 68
Stable Isotopes .......................................... 69
Basin Geochemistry .......................................... 70
Field Properties and Major Ions .......................... 70
Nutrients and Dissolved Organic Carbon ................... 73
Stable Isotopes .......................................... 73
Overview of Water Quality and Geochemistry .................. 75
Wetland Flooding Characteristics ............................... 77
Methods of Flooded Area Determination ....................... 78
Changes in Extent of Flooded Area ........................... 78
Marshes .................................................. 79
Cypress Wetlands ......................................... 81
Comparison of Recent and Historical Flooded Area Duration
Distributions ............................................... 83
Natural Wetlands ......................................... 84
Augmented Wetlands ....................................... 87
Impaired Wetlands ........................................ 87
Seasonal Average Flooding Patterns .......................... 91
Overview of Flooding Characteristics ........................ 93
Wetland Ecology ................................................ 95
Methods of Ecological Data Collection and Interpretation .... 95
Periphyton ............................................... 95
Wetland Vegetation ....................................... 96
Macroinvertebrates ....................................... 97
Periphyton .................................................. 98
Biomass and Chlorophyll-a ................................ 98
Community Composition .................................... 99
Wetland Vegetation ......................................... 102
Comparison of Vegetation Communities .................... 102
Species Richness ........................................ 104
Relative Abundance of Wetland Plants by Indicator
Category ................................................ 105
Plant Biomass in Marshes ................................ 109
Tree Density and Size in Cypress Wetlands ............... 109
Effects of Environmental Stressors on Wetland Plant
Communities ............................................. 109
Macroinvertebrates ......................................... 112
Marsh Macroinvertebrate Communities ..................... 112
Marsh Macroinvertebrate Communities ..................... 112
Cypress Macroinvertebrate Communities ................... 119
Functional Feeding Groups ............................... 119
Macroinvertebrates as Ecological Indicators in
Wetlands ................................................ 127
Overview of Wetland Ecology ................................ 130
Summary and Conclusions ....................................... 131
References Cited .............................................. 135
Glossary ...................................................... 145
Appendixes
1. Monthly rainfall at the marsh wetlands .................... 147
2. Monthly rainfall inside the canopy at the cypress
wetlands .................................................. 148
3. Relation between rainfall measurements inside and
outside of the tree canopy at the cypress wetlands ........ 149
4. Evapotranspiration estimates for marsh and cypress
wetlands .................................................. 150
5. Bathymetric maps for the 10 study wetlands showing
location of vegetation plots .......................... 151-152
Figures
1. Diagram showing conceptualized isolated wetland
showing the changing size of the flooded area ............. 4
2. Map showing location of study wetlands in the
northern Tampa Bay area, west-central Florida ............. 6
3-5. Graphs showing:
3. Regional annual rainfall departures from the long-term
average, 2000 to 2004 ..................................... 8
4. Annual rainfall measured at the marsh and cypress
wetlands during 2001 to 2003 compared to the long-term
average rainfall .......................................... 8
5. The average annual daily ground-water withdrawal from
the 11 Tampa Bay Water well fields, 1988 to 2004 .......... 8
6-8. Diagrams showing:
6. Approximate time line of data collection in the two
wetland types ............................................. 9
7. Landscape features and hydrogeologic framework of
mantled karst terrain in west-central Florida ............ 14
8. Example of dissolution and subsidence forming wetlands
in mantled karst terrain ................................. 14
9. Maps showing location of data-collection sites for the
marsh wetlands ........................................... 22
10. Maps showing location of data-collection sites for
the cypress wetlands ..................................... 23
11-18 Generalized hydrogeologic sections and vertical head
distribution for:
11. HRSP Natural Marsh at Hillsborough River State Park ...... 24
12. Duck Pond Augmented Marsh at Cross Bar Well Field ........ 25
13. W-3 Augmented Marsh at Cypress Creek Well Field .......... 26
14. W-29 Impaired Marsh at Cypress Creek Well Field .......... 27
15. S-68 Natural Cypress at Starkey Well Field ............... 28
16. S-63 Augmented Cypress at Starkey Well Field ............. 29
17. W-5 Augmented Cypress at Cypress Creek Well Field ........ 30
18. W-19 Impaired Cypress at Cypress Creek Well Field ........ 31
19-22 Graphs showing:
19. Vertical profiles of bulk gamma density and grain size
in sediment cores from GS Natural Marsh and W-29
Impaired Marsh ........................................... 33
20. Average, minimum, and maximum radium-226 activity from
surface sediment samples collected in July 2002 and May
2004 ..................................................... 34
21. Vertical profiles of radium-226 activity in sediment
cores taken from W-3 Augmented Marsh, W-29 Impaired
Marsh #1, W-29 Impaired Marsh #2, and GS Natural Marsh ... 34
22. Ground-penetrating radar profiles with interpreted
geologic features below W-29 Impaired Marsh, Duck Pond
Augmented Marsh, S-63 Augmented Cypress basin, and Duck
Pond Augmented Marsh basin ............................... 36
23. Diagram showing conceptualized interactions of wetlands
with ground-water recharge and ground-water flow
through .................................................. 37
24. Maps showing ground-water flow patterns around the
marsh wetlands during representative dry-season
conditions ............................................... 38
25. Graphs showing wetland stage and ground-water levels in
selected surficial and Upper Floridan aquifer wells in
the marsh wetland basins ................................. 39
26. Maps showing ground-water flow patterns around cypress
wetlands during representative dry-season conditions ..... 41
27. Graphs showing wetland stage and ground-water levels in
selected surficial and Upper Floridan aquifer wells in
the cypress wetland basins ............................... 42
28-31 Box plots of:
28. Daily linear leakage rates in the study wetlands ......... 49
29. Downward head differences at each wetland during its
water-budget period ...................................... 50
30. Elevation differences between the bottom of the wetland
and the head in the Upper Floridan aquifer at W-29
Impaired Marsh forthree time periods, marshes from
December 2000 through September 2002, and cypress
wetlands from November 2002 through July 2004 ............ 51
31. Leakance below the study wetlands ........................ 53
32-36 Graphs showing:
32. Annual water budget for Duck Pond Augmented Marsh in
2001 ..................................................... 54
33. Daily water-budget residual for Duck Pond Augmented
Marsh and head in the Upper Floridan aquifer during
December 2000 - September 2002 ........................... 54
34. Daily average head in the Upper Floridan aquifer in
relation to daily linear leakage rate from Duck Pond
Augmented Marsh .......................................... 54
35. Daily rainfall, daily water-budget residual, and head in
the Upper Floridan aquifer at S-63 Augmented Cypress
wetland during November 2002-July 2004 ................... 55
36. Daily average head in the Upper Floridan aquifer in
relation to daily linear leakage rate at S-63 Augmented
Cypress wetland .......................................... 55
37. Maps showing water-table configuration at W-5 Augmented
Cypress wetland on May 10,2004 before augmentation, and
on June 1,2004 after 23 days of augmentation ............. 57
38-40 Graphs showing:
38. Daily augmentation volume and flooded area in W-5
Augmented Cypress wetland during the augmentation
experiment ............................................... 58
39. Response of the water table below W-5 Augmented Cypress
wetland to augmentation .................................. 58
40. Daily linear leakage rate and flooded area in W-5
Augmented Cypress wetland during the augmentation
experiment ............................................... 58
41. Stiff diagrams for surface water in marsh and cypress
wetlands ................................................. 65
42. Box plots of field properties and chemical constituents
in surface waters of augmented and unaugmented
wetlands ................................................. 67
43. Plot showing organic nitrogen and dissolved organic
carbon in wetland surface water .......................... 69
44. Box plot of nitrogen to phosphorus ratio in wetland
surface water ............................................ 70
45. Plot showing delta deuterium and delta 18O in wetland
surface water and augmentation water ..................... 70
46. Stiff diagrams for surface water and shallow ground
water at selected wetlands ............................... 71
47. Plots showing delta deuterium and delta 180 in wetland
surface water, shallow ground water, and augmentation
water from the Upper Floridan aquifer at W-5 Augmented
Cypress, S-63 Augmented Cypress, and S-68 Natural
Cypress .................................................. 74
48. Graphs showing percentage of the total wetland area
flooded on average each week in the natural, augmented,
and impaired marshes from December 12,2000 to September
30,2002 .................................................. 80
49. Plot showing soil moisture content in HRSP Natural
Marsh and W-29 Impaired Marsh during the same time
period ................................................... 81
50. Plot showing the relation between daily average soil
moisture in the top one foot of soil and the daily
average water-table depth below W-29 Impaired Marsh ...... 81
51. Graphs showing percentage of the total wetland area
flooded on average each week in the natural, augmented,
and impaired cypress wetlands from December 11,2002 to
July 27,2004 ............................................. 82
52. Graph showing hourly variation in flooded area at S-63
Augmented Cypress from December 24,2003 to December
31,2003 .................................................. 82
53. Diagrams showing conceptualized wetland showing the
boundary of the flooded area located in different 20-
percent intervals of the total wetland area .............. 83
54-58 Graphs showing the recent and historical flooded-area
duration distributions and maps showing the shapes of
these flooded areas in:
54. GS Natural Cypress and S-68 Natural Cypress .............. 85
55. HRSP Natural Marsh and GS Natural Marsh .................. 86
56. Duck Pond Augmented Marsh and W-3 Augmented Marsh ........ 88
57. W-5 Augmented Cypress and S-63 Augmented Cypress ......... 89
58. W-29 Impaired Marsh and W-19 Impaired Cypress ............ 90
59-65 Graphs showing:
59. Historical monthly average flooded area in the study
wetlands ................................................. 92
60. Relative abundance of dominant algal groups in marsh
and cypress wetlands ..................................... 99
61. Relative abundance of obligate, facultative wet,
facultative, and facultative upland plants in marsh
and cypress wetlands .................................... 108
62. Number of tolerant and intolerant plant species at
natural, impaired, and augmented wetlands ............... 110
63. Biomass, density, and taxa richness of
macroinvertebrates in marsh wetlands .................... 112
64. Shannon diversity of macroinvertebrates in marsh and
cypress wetlands ........................................ 113
65. Biomass, density, and taxa richness of
macroinvertebrates in cypress wetlands .................. 120
66. Pie chart showing the proportion of macroinvertebrate
functional feeding groups in marsh and cypress
wetlands ................................................ 121
67. Graph showing abundance of Chironomidae, all Diptera,
and all macroinvertebrates in marsh and cypress
wetlands ................................................ 128
Tables
1. Average ground-water withdrawal rates at selected Tampa
Bay Water regional well fields during the study ........... 9
2. Names, locations, and physical characteristics of study
wetlands ................................................. 10
3. Well characteristics and data collected for wells used in
the study ................................................ 16
4. Water-budget characteristics and selected flux rates for
the study wetlands ....................................... 47
5. Wetland leakage rate statistics .......................... 49
6. Regression results relating the daily rainfall volume to
the daily change in wetland volume at the unaugmented
wetlands ................................................. 59
7. The volume ratio of runoff to rainfall in the study
wetlands ................................................. 59
8. Range and median water quality for surface water in
wetlands ................................................. 66
9. Range and median water quality for ground water in
wetland basins ........................................... 72
10. Description of stage data used for the historical
flooding analyses ........................................ 79
11. Percentage of the historical time each wetland area
interval was flooded ..................................... 87
12. The percentage of time that more than half of the total
wetland area was flooded, based on stage data from 1996
to 2003 .................................................. 93
13. Average duration of flooding at deepest point in
wetland, in months per year, based on stage data from
1996 to 2003 ............................................. 93
14. Median biomass of periphyton samples collected in study
wetlands, 2002-04 ........................................ 98
15. Median biomass and chlorophyll-a of periphyton samples
collected in study wetlands during September-October
2003 ..................................................... 98
16. Median diatom species richness and most abundant
diatom species in study wetlands ........................ 100
17. Van Dam Ecological Indicator values for diatoms in
study wetlands .......................................... 101
18. Jaccard's Similarity Index matrices (using all species
greater than 1 percent of abundance) for vegetation in
fixed plots in marsh wetlands, 2000-04 .................. 102
19. The percentage of time that fixed vegetation plots
were flooded during the recent period (2000-02 or
2002-04), based on stage data and bathymetry ............ 103
20. Jaccard's Similarity Index matrices (using all species
greater than 1 percent of abundance) for vegetation in
fixed plots in cypress wetlands, 2000-04 ................ 104
21. Jaccard's Similarity Index comparing vegetation in
fixed plots sampled during 2000-02 (the period of
average rainfall) with vegetation in fixed plots
sampled during 2002-04 (the period of above-average
rainfall and reduced ground-water pumping) .............. 105
22. Plant species in fixed and randomly located plots in
marsh wetlands .......................................... 106
23. Plant species in fixed and randomly located plots in
cypress wetlands ........................................ 107
24. Biomass of vegetation in marsh wetlands ................. 109
25. Wetland plants that tend to decrease or increase in
abundance with disturbance .............................. 111
26. Summary of macroinvertebrate community assessment ....... 113
27. Mean density, frequency of occurrence, and functional
feeding group classification of macroinvertebrates
in marsh wetlands ................................... 114-118
28. Mean density, frequency of occurrence, and
functional feeding group classification of
macroinvertebrates in cypress wetlands .............. 122-126
29. Occurrence offish and larval amphibians (tadpoles)
in study wetlands ....................................... 129
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