Freshwater Inflow to Tampa Bay Why do we care ?

- Circulation and material transport

- Salinity and water quality, linkage to nutrient loading and biological resources (seagrasses, benthos)

- Fisheries production OTB

HB

MTB

BCB

LTB TCB

MR Gaged ~ 65 % Of watershed area

Gaged and ungaged basins Total Yearly Inflow to Bay

Total Source m3/year x 10 6 % of Total

Rainfall 1,349 39%

Point sources 293 8%

Ground water 107 3%

Streamflow and 1,741 50% ungaged runoff Total Yearly Inflow to Bay

Total % of Total Source m3/year x 10 6 w’out Manatee R.

Rainfall 1,349 39% 43%

Point sources 293 8%

Ground water 107 3%

Streamflow and 1,741 50% 44% ungaged runoff Percentages of total streamflow + point sources

12% 38%

17%

5%

3% 1%

24% Percentage of Yearly Rainfall and Streamflow by Month for the Alafia River Basin 20 20 18 Rainfall 18 16 Streamflow 16 14 14 12 12 10 10 8 8 6 6 Rainfall (%) 4 4 Streamflow (%) 2 2 0 0 Jul Oct Jan Dec Feb Apr Jun Mar May Aug Nov Month Sept Dry Wet

Hydrodynamic models of river and sub-bays

• Lower Hillsborough River - SWFWMD, HydroQual, Inc.

• Lower Alafia River - SWFWMD

• Tampa Bypass Canal and McKay Bay – USF, HydroQual, Inc.

• Little Manatee River – FSU/FAMU

• Manatee River - SWFWMD , USF Little Manatee River Model Grid System 0

0

2

2

4 4

4 6 6

6

10 2 exceedance) (14%

8 (~ 92% exceedance) 92% (~

2

1 4

14

0

1 6 River KM

River KM 8 16 0

2 4

1 1

2 4 6

4 0 2 4 6 8 1012141618202224262830

6 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 0 2 6 1

8 1 0 1

8

0

2 aiiyDsrbtos July 27,Salinity Distributions, 2003 aiiyDsrbtos pi 20, April 2000 Distributions, Salinity

2

1 2 24 2 2

26 4 4 8 1 2

4

6 July 27, 2003; Inflow to upper estuary = 611 cfs cfs 611 = estuary upper to Inflow 2003; 27, July 6

2

1

April 20, 2000; Inflow to upper estuary = 73 cfs cfs 73 = estuary upper to Inflow 2000; 20, April

0 6

1

2 2 2 F. A. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

1 0 -1 -2 -3 -4 -5 -6 -7

1 0 -1 -2 -3 -4 -5 -6 -7

lvto (m) Elevation lvto (m) Elevation Alafia River - Gaged and Ungaged ( ) Basins Freshwater inflows – Needs for improved modeling applications

• More streamflow gages? Assess cost, accuracy, and utility

• Quick access to rainfall and streamflow data, either real-time or retrieved within days or weeks

• Reasonably accurate hydrologic models to estimate ungaged runoff to the bay – precision vs. effort and turnaround

• Improved rainfall networks needed to support ungaged runoff estimation, regardless of modeling method

• More refined runoff and estuarine models for rivers and sub-bays

• Improvements in matching basin delineations with estuarine model input nodes for freshwater inflows