Demand_Forecast

• Title: SWSI Water Demand Forecast
• Date: 8/6/2004
• SWSI - Doc Type: Supporting Documents

I. Introduction

This technical memorandum presents the findings from an analysis of water
use throughout the State of Colorado. The analysis includes the following:

. Collection of available statewide water use, demographic and weather
data

. Review of available urban water demand studies conducted throughout
the state

. Evaluation of available information to determine factors that influence
urban water demand

. Prepare a statewide forecast of future urban water demand to the year
2030 by county and basin

The objectives of this analysis are to:

. Develop a reconnaissance-level water demand forecast
. Use consistent data and methodology throughout the state
. Utilize available data without extensive data-collection effort

The originally proposed methodology for estimating urban water demand
was based on the assumption that total urban water use data would be
available for each county. However, this data source was found to contain
water use data for only a limited number of water providers within counties
and did not provide coverage for all counties. Thus, the methodology used
for estimating urban water demand is based on a sample of water providers
throughout the state, as described in this memorandum.

Municipal level characteristics were identified for each of the providers in the
sample database. Regression analysis was used to examine relationships
between the municipal characteristics and municipal per capita water use in
an effort to develop a model of per capita water use. The results of this
statistical analysis are presented. Ultimately, the statistical modeling effort
did not produce the desired results. Thus, per capita water use was estimated
for each county from the sample database.

Future population projections by county were obtained from the Colorado
Department of Local Affairs (DOLA), Demography Section. The estimated
per capita water use rates for each county are multiplied by the projected
population of each county to estimate current and future urban water
demand (i.e., the residential, commercial and industrial water use) of each
county.

This estimation of county per capita water use assumes that all residences,
businesses and industries throughout the county (including most self-
supplied users) use water at the same rate as the provider-supplied
residences, businesses and industries that are represented in the sample
database. Where data were available regarding unique large self-supplied

1. Introduction

1