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Catawba-Wateree Water Supply Master Plan

2006 Water Supply Study found maximum capacity of Catawba River Basin for water supply could be reached mid-century

Catawba-Wateree Water Management Group incorporated - December 2007

Water Supply Master Plan commissioned in 2010

Purpose of Master Plan is to find ways to extend the time before the capacity of the Basin is reached

Background

4,750 square miles Supports nearly two million people with

water for drinking, power generation, industrial processes, crop and livestock production, recreation, irrigation, and more

The Catawba-Wateree River Basin

Project was funded by: Duke Energy Foundation North Carolina Department of Environment and

Natural Resources

South Carolina Department of Natural Resources Catawba-Wateree Water Management Group

Acknowledgements/Thanks

Supplemental funding Stakeholder input Water use projections Refinement of hydrologic model Climate change impacts Develop & evaluate options Action plan and schedule Publish report Implementation, on-going public input Periodic future updates

Elements of the Master Plan

Advisory level input by key organizations with an interest in future planning efforts for the Basin Intended to ensure a broad level of input from a diverse group of interested stakeholders

Stakeholder Advisory Team (SAT)

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Million gallons per day (mgd) consumed and percent of total 419.4 mgd

How Water will be Used (2065)

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Steam/Electric Power178.3, 43%

Industrial7.7, 2%

Public Water Supply198.5, 47%

Agriculture/Irrigation34.9, 8%

Water Use ProjectionsPicture or Color Block

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Safe Yield Studyo How to define and determine safe yieldo Can safe yield be increased?

Sedimentation Monitoring Study

Water Use Efficiency Study

Low Inflow Protocol Response Evaluation Study

Full reports can be found at www.catawbawatereewmg.org

Pre-Master Plan Project Research

Sensitivity Analysis

Evaluated variation in population growth Evaluated climate change impacts

o No impactso Baseline (moderate) impacts – focused on temperature riseo High impact – temperature rise and reduced precipitation/inflow

CWWMG – First in the region to incorporate climate change into water use planning

Population and Climate Change

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Playing the “What If?” Game with a Robust Water Model

Baseline Population growth Climate change Public water supplier water use changes (water use efficiency, reroute wastewater) Power consumptive water use changes (e.g. relocation of demand) New off-stream storage reservoirs Critical intake modifications Effluent flow recycling Modified reservoir operations Low Inflow Protocol (drought management plan) modifications

Individual and Integrated Future Planning Scenarios

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Improve safe yield of the Basin by over 200 mgd

Extend water yield by 40 years

Results and Recommendations

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Increase water use efficiency Lower critical water intakes/elevations

o Power planto Public water supply

Raise target lake levels during summer months Enhance drought responsiveness through Low

Inflow Protocol

Key Recommendations

Example: average per capita use in the Charlotte-Mecklenburg systemo Current ~100 gallons/day/person (residential)o Recommended 2065 ~80 gallons/day/person (residential)

Water Use Efficiency RecommendationsPicture or Color Block

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Where’s the Water Going?CW Reservoir System Water Balance

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Wateree Hydro Station outflows 3,359 mgd(1,085 mgd)

Natural surface evaporation 204 mgd (all eleven lakes combined)(204 mgd)

Surface and groundwater inflow3,752 mgd(1,491 mgd)

Public Water Supply92 mgd(98 mgd)

Industrial3 mgd(6 mgd) Thermal

Power74 mgd(78 mgd)

Irrigation 20 mgd(20 mgd)

Water withdrawals are average net amounts for 2006–2013 and total 189 mgd (202 mgd)

Natural inflow, natural evaporation, and hydro outflow are annual average amounts from hydrology data set used in CHEOPS™ model

* mgd = million gallons per day. To convert to cubic feet per second (cfs), multiply all numbers by 1.5475

Values in italics represent corresponding inflow, withdrawals, and outflow for the worst 12 months during the 2007-2009 drought (7/01/2007 to 6/30/2008)

So What is Duke Energy’s Role?

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Manage the Water Resource Manage the region’s raw water supply (big, ongoing investment) Implement Comprehensive Relicensing Agreement (CRA) and new license Continue making electric customers more energy-efficient. In 2009-2014, Duke Energy’s energy

conservation programs across the Carolinaso Reduced capacity needs by total of ≈ 1,200 MW (about a nuclear unit)o Reduced energy needs by total of ≈ 2,442,000 MWh (about a billion gallons of water equivalent)

So What is Duke Energy’s Role?

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Be a Good Partner Remain a dues-paying, active member of the

Catawba-Wateree Water Management Group Help provide leadership and coordination

Implement the Water Supply Master Plan Pursue the identified initiatives

o Water use for thermal plant replacements/additionso Quicker response in Low Inflow Protocolo Increase summer target elevations for selected

reservoirs

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Implementation of the Catawba-Wateree Water Supply Master Plan extends the River’s capacity to sustain growth through 2100

Projected Results

Complete Water Supply Master Plan Report is available at www.catawbawatereewmg.org

Questions?

Additional slides for further discussion

Reference

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Once-Through Cooling

Used at Marshall, McGuire and Allen Steam Stations

Pros (compared to cooling towers)o Much more water use efficiento Higher plant efficiencyo Thermal refuge for fish in cold months

Cons (compared to cooling towers)o Heats up the lake (regulated by permit)o Higher risk to fish (impingement and

entrainment)

Thermal Power Cooling Technologies Used on the CW

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Cooling Towers (aka Closed Loop Cooling)

Used at Catawba Nuclear Station Pros (compared to once-through cooling)

o Much lower gross water withdrawal rateo Negligible thermal impact to the lakeo Reduced risk of impacting fish

Cons (compared to once-through cooling)o Consumes 30-40% more water per unit of

electricity producedo Lower plant efficiency

Thermal Power Cooling Technologies Used on the CW

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Growth Future electrical demand projected to double in

next 50 years Energy efficiency success Thermal power will be a key source CW lakes will support some portion of growth

Power Plant Retirements, Replacements and Additions Natural gas - most replacement and new

plants in WSMP are more water use efficient (gas-fired combined cycle) than existing plants

Moving downriver - located water withdrawals for some new plants further down the river system

Research and Development Water Research Center, Cartersville, GA Technologies must be proven regionally viable,

reliable and cost-effective at plant scale Cooling system modification at SCE&G’s

Wateree Steam Station does not reduce water consumption

Factors Driving Future Thermal Power Cooling Water Use

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