Water Supply Impact StudyMichael Cullum, P.E., Director, EngineeringSt. Johns River Water Management District

March 30, 2010

Water Supply Impact Study (WSIS)

Primary Focus of the Meeting is the Hydrology and Hydrodynamic Modeling Effort

General Process1. HSPF - Watershed Runoff Model (USJ+others)2. EFDC - River Hydrodynamic Model (MSJ/LSJ)3. Environmental Analyses (Steps 3+)

WSIS Scenarios

In addition, the Uncertainty Analysis for the River EFDC runs will also examine the potential effects of channel dredging,

wastewater reuse, and variable rates of Sea Level Rise.

1995 Landuse 1995 Landuse with USJ Restoration Projects

2030 Landuse with USJ Projects with and without Sea Level Rise (SLR)

1995 landuse with ½ SJR withdrawal

1995 LU w/Restoration Projects with ½ SJR withdrawal

2030 LU w/Projects + (SLR) with ½ SJR withdrawal

1995 Landuse with Full SJR withdrawal

1995 LU w/Restoration Projects with Full SJR withdrawal

2030 LU w/Projects + (SLR) withFull SJR withdrawal

1995 Landuse with Full SJR + Ocklawaha withdrawals

1995 LU w/Restoration Projects with Full SJR + Ocklawaha withdrawals

2030 LU w/Projects + (SLR) with Full SJR + Ocklawaha withdrawals

WSIS Scenarios1995 Landuse1.Water Supply Planning Base Year2.Stable USJ Project Conditions3.Good Data set 1995-20064.Use for Calibration of Models5.Landuse changes are variable regardless of timeframe

1995 Landuse with withdrawals1.Provide worst case scenario, not likely2.Test robustness of the models

1995 Landuse

1995 landuse with ½ SJR withdrawal

1995 Landuse with Full SJR withdrawal

1995 Landuse with Full SJR + Ocklawaha withdrawals

WSIS Scenarios1995 LU with Restoration Projects1.C1 Rediversion – 90% complete, ETC 20112.Three Forks WMA – 90% complete, ETC 20123.Fellsmere WMA – 20% complete, ETC 2014

Withdrawals not anticipated prior to 2020

1995 Landuse with USJ Restoration Projects

1995 LU w/Projects with ½ SJR withdrawal

1995 LU w/Projects with Full SJR withdrawal

1995 LU w/Projects with Full SJR + Ocklawaha withdrawals

Fellsmere

Three Forks

C-1 Basin

SJR at Cocoa

SJR at Christmas

WSIS Scenarios2030 LU with Projects and (SLR)1.USJ Projects will be constructed2.Landuse Estimates are high by 10%3.2010/2015 LU not available, can interpolate between 1995 & 20304.Include Conservative Sea Level Rise

Sea Level Rise is expected. More detailed evaluation in Uncertainty Analysis

2030 Landuse with USJ Projects with and without Sea Level Rise (SLR)

2030 LU w/Projects + (SLR) with ½ SJR withdrawal

2030 LU w/Projects + (SLR) withFull SJR withdrawal

2030 LU w/Projects + (SLR) with Full SJR + Ocklawaha withdrawals

WSIS Scenarios

In addition, the Uncertainty Analysis for the River EFDC runs will also examine the potential effects of channel dredging,

wastewater reuse, and variable rates of Sea Level Rise.

1995 Landuse 1995 Landuse with USJ Projects

2030 Landuse with USJ Projects with and without Sea Level Rise (SLR)

1995 landuse with ½ SJR withdrawal

1995 LU w/Projects with ½ SJR withdrawal

2030 LU w/Projects + (SLR) with ½ SJR withdrawal

1995 Landuse with Full SJR withdrawal

1995 LU w/Projects with Full SJR withdrawal

2030 LU w/Projects + (SLR) withFull SJR withdrawal

1995 Landuse with Full SJR + Ocklawaha withdrawals

1995 LU w/Projects with Full SJR + Ocklawaha withdrawals

2030 LU w/Projects + (SLR) with Full SJR + Ocklawaha withdrawals

Differences from Phase 1 Scenarios

• Added Projects to 1995 Landuse• Added 2030 Landuse• Changed Location of Withdrawals

(55 MGD for Taylor Creek in USJ, 100 MGD in MSJ)

• Phase 1 (Zero withdrawal Taylor Creek, All 155 MSJ)• Phase 1 Results

1. 4 cm single hour decrease in MSJ2. 1 cm single hour decrease in LSJ

Water Supply Impact Study (WSIS)March 29-31, 2010

1. St. Johns River Watershed Hydrology2. HSPF Model Description and Calibration3. MSJ/LSJ River Hydrodynamics4. MSJ/LSJ EFDC Description and Calibration5. Uncertainty Analysis6. Scenarios and H&H Results