Draft 2025 Urban Water Management Plan

2025 Orange County Water Demand Projection Model

Table 3-5: CII Regression Variables and Coefficients

Explanatory Variable

General Directional Influence

Model Coefficient Range

Proportion of Total Jobs in Retail Proportion of Total Jobs in Education Proportion of Total Jobs in Services

+ + + +

0.42

0.287 0.294

GDP

0.81

Marginal price (per 20 CCF)

-

-0.114

Departure from normal monthly maximum temperature Departure from normal monthly maximum temperature (lagged 1 month) Departure from normal monthly precipitation Departure from normal monthly precipitation (lagged 1 month) Departure from normal monthly precipitation (lagged 2 month)

+

0 to 1.63

+

0 to 0.7

-

0 to -0.50

-

0 to -0.06

-

0 to -0.034

Residual Trend

- -

-0.01 to 0.01 -0.24 to 0.17

State Requested Percent Restriction

The coefficients for CII indicate the job proportion used: total services portion, total education portion, and total retail portion. CII use per job is positively correlated with each job proportion as well as gross domestic product throughout Orange County.

3.5.2

Historical Model Performance

Visual inspection and performance metrics showed good model performance, including the same seasonal cycle and quantities. Like other classes, most fits exceed an R 2 of 80%. Figure 3-4 shows the model performance for an example agency.

3-12

Appendix G - 49

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