Draft 2025 Water Shortage Contingency Plan

Learn more at irwd.com/doing-business/urban-water-management-plan.


Overview
3

WSCP Requirements & Sections
3

Past Implementation of WSCP
4

Section 1 – Analysis of Supply Reliability and Seismic Risk Assessment
6

1.1 Supply Reliability Scenario Planning
6

1. 2 Catastrophic Interruption
7

1.3 Seismic Risk Assessment and Mitigation Plan
9

A. Excerpts from IRWD Water System Risk and Resilience Assessment (RRA)
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I. Overview of Water Emergency Preparedness in Orange County
10

II. Assessment Approach
11

III. Key System Elements
11

IV. Vulnerability Assessment
11

V. Earthquake Liquefaction
11

VI. Seismic Mitigation Actions
12

1.4 Multiple Dry Year Analysis and Drought Risk Assessment
12

Section 2 – Annual Water Supply and Demand Assessment Procedures
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2.1 Water Supply and Demand Assessment Requirements
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2.2 Annual Water Supply and Demand Assessment Procedures
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A. Key Data Inputs
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B. Assessment Methodology and Procedures
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Step 1: Access Historic Customer Use Data
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Step 2: Determine Available Supplies
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Available Supply Coordination: OCWD & Groundwater
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Available Supply Coordination: Metropolitan & MWDOC (Imported Water)
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Available Supply Coordination: Water Banking
18

Step 3: Calculate Projected Customer Demands for Year 1
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Step 4: Apply Adjustments for Expected Weather, Growth, and Capacity Changes
19

Step 5: Calculate Projected Customer Demands for Year 2 (Single Dry Year)
20

Step 6: Compare Total Supply and Demands – Assess Possible Shortage
20

Step 7: Initiate Shortage Response Actions (SHORTAGE CONDITION ONLY)
21

Review of Decision-Making Process
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Description and Quantification of Each Water Supply Source
22

C. Reporting
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Section 3 – Six Standard Shortage Stages
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3.1 Imported Water Shortage
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3.2 Emergency Supplies
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3.3 Stages of Action by Level
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Section 4 – Additional Shortage Response Actions
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4.1 Standard IRWD Practices for Shortage Response
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4.2 Voluntary Reduction Measures
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4.3 Use of Budget-Based Rates
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4.4 End-Use Prohibitions
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4.5 Critical Shortage Measures
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4.6 Operational Drought Control Measures
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Section 5 – Communication Protocols
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Section 6 – Compliance and Enforcement
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Section 7 – Legal Authorities
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Section 8 – Financial Consequences
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8.1 Cost of Compliance
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Section 9 – Monitoring and Reporting
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Exhibit A – Draft Water Shortage Contingency Resolution
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Exhibit B – EPA Emergency Response Plan (ERP) Certification Receipt and Confirmation
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Exhibit C – Orange County Water and Wastewater Multi-Jurisdictional Hazard Mitigation Plan
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