2025 Orange County Water Demand Projection Model
CDR Projection Difference from LODES (CDR-LODES)/LODES
Total 2019 Jobs (LODES)
Agency
Total 2019 Jobs (CDR)
Serrano WD
1,521
2,288
50.43% 12.26% 98.52% -39.34% -8.87% 7.15%
South Coast WD
13,305
14,936
Trabuco Canyon WD
1,312
2,605
Tustin
37,530 30,892 24,139
22,765 28,153 25,866
Westminster
Yorba Linda WD
The differences in actual job numbers across the two data sources vary by agency. The actual jobs implemented in the forecast were based on conversations with each agency. For most retail agencies, the job growth rate predicted by CDR, rather than actual job numbers, is used. However, in cases where agencies indicated that CII demands differed from observed Fiscal Year 2024-2025 values, Hazen substituted the job source (CDR or LODES) that provided a forecast closer to observations. 2.2 Collection and Processing of Explanatory Variables Explanatory variables are variables specified in a regression model to explain variability in water use, such as water rates, maximum monthly temperature, housing density, and other socioeconomic parameters. Explanatory variables used in the econometric demand model are identified based on adherence to three key characteristics:
1) Logical or understood connection to explaining changes in water consumption;
2) Historical records available for the historical modeling period; and
3) Availability of future projections consistent with the desired forecast horizon (2025-2050) or a reasonable means for assuming or deriving projected values. Table 2-6 provides an overview of the collected explanatory variables for Orange County water agencies’ demand models and their relevance to explaining changes in water consumption.
Table 2-6: Summary of Explanatory Variables
Explanatory Variable
Relevance to Water Consumption
Temperature
Higher than normal temperatures are associated with higher demands.
Precipitation
Higher than normal rainfall is associated with lower demands.
Price
Economic theory suggests a negative correlation with demand.
Water demand is positively correlated with real GDP, which is modeled as departure from the long-term trend.
Economic Index
Economic theory suggests a positive correlation between income and demand; generally, areas with higher median incomes tend to use more water.
Median Income
2-9
Appendix G - 28
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