Water Supply Assessments

LADWP Board Meeting July 21, 2015

David R. Pettijohn Director of Water Resources

Los Angeles Department of Water and Power

State Law Requirement

Water Code 10910-10915 – As part of CEQA, City is required to

prepare a Water Supply Assessment (WSA) for large developments.

– Determine if total projected water supplies available during normal, single dry, multiple dry years over a 20-year period will meet project’s demand, in addition to City’s future demands

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Water Supply Assessment

• Identification of Water Supplies

• Detailed Project Description

• Calculation of Project’s Water Demand

• Compliance with current ordinances

• Determination of whether the Project’s water demand was included in the most recently adopted UWMP

• Statement of Findings

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520000

570000

620000

670000

720000

770000

2015 2020 2025 2030 2035

Acre

-Fe

et

Year

Forecasted WSA Project Demand

Forecasted Demand

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77%

23%

Future Demand Growth

Urban Water Management Plan

Supply Growth

5

Today

Future

When Would We Not

Recommend WSA Approval?

Water Code 10911 – Assess plans for acquiring additional

water supplies

Supplies Impacted by: – Loss of supply(s);

– Catastrophic disruption;

– Natural disaster;

– Regulatory / Environmental; or

– Drought Year Supply Shortage

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11 Recycled Water

79 Local Groundwater

61 Los Angeles

Aqueduct

334 MWD

0

100

200

300

400

500

600

Projected 15/16 Supplies

Th

ou

sa

nd

Acre

-Fe

et

(TA

F)

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Governor’s Executive Order (474 TAF)

Mayors ED5 (485 TAF)

Current Dry Year Supplies

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Projects That Require a WSA

Water Code 10912 – Residential development > 500 dwelling

units

– Shopping center/ business establishment > 500,000 s.f.

– Commercial office building > 250,000 s.f.

– Hotel/Motel > 500 rooms

– Industrial development > 40 acres of land or 650,000 s.f. floor space

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Water Demand Estimate

• Net Additional Water Demand = Proposed – Existing – Conservation

• Proposed Indoor Building Outdoor Landscaping Cooling Towers

• Existing Water Use Billing Records

• Conservation

Required by City Ordinances Additional Voluntary Recycled Water

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Proposed Water Demand

• Indoor Building – Sewer Generation Factors (SGF)

• Cooling Towers • Outdoor Landscaping

– Model Water Efficient Landscape Ordinance

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Slide

Water Use Factors

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Slide

Demand Calculations

Required for Board Approval

Current Adopted UWMP

– Water demand projections based on Southern California Association of Governments (SCAG) demographic projections

Project Consistency with SCAG

City’s General Plan

– Community Plans: based on the SCAG data.

Determination of Adequate Supplies

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WSA Findings

• Determination of sufficient water supplies to meet Project’s demand during normal, single dry, and multiple dry years for the next 25 years

• Determination of Project’s water demand falls within the City’s water demand growth projection

• Estimate of Project’s Additional Water Demand

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