Demand_Forecast

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

III. Data Collection and Analysis
Data Collection

Demographic and water use data were aggregated from various sources and
organized to create a sample database. This database contains 167
observations and includes names and locations of water providers, total
water use into the distribution system, water use in gallons per capita day
(gpcd), population, median household income, number of households,
household size, a single-family housing ratio, employment ratios and
weather data.

Most names and locations of water providers contained in the sample
database were obtained from the Colorado Drought Survey conducted by the
Colorado Water Conservation Board. This Drought Survey served as the
foundation of the sample database as it supplied a list of providers with their
associated county, basin, 1999-2002 water use and a service area population
range. The majority of the providers' gpcd values in the sample database
were calculated using the water use data obtained from the Drought Survey.

Provider-level population data were derived from one of three sources: the
U. S. Census Bureau, the Colorado Department of Public Health and
Environment - Public Water Systems (PWS), or an independent survey
conducted by CDM. The CDM survey was a brief survey administered in the
Fall of 2003 by email to water providers throughout the state. Approximately
42 responses were received to this survey. The PWS data included a list of
water providers, their location, and" registered population," which is
assumed to be the provider service area population. The PWS provided a
consistent source for population data, however it was not available for every
provider. When PWS population data were not available, Census place-level
data were used. Data from the CDM survey were used as available. In
addition, the review of available independent water demand studies from
throughout the state provided year 2000 water use and service area
population for some providers. (Note that additional data were added to the
database after the modeling analysis, as discussed in the section on per capita
results.)

Thus, the gpcd values for each provider in the sample database were
calculated as one of the following:

. Drought Survey water use divided by PWS population
. Drought Survey water use divided by Census population
. CDM survey water use divided by CDM survey population
. CDM survey water use divided by PWS or Census population
. Water use and population served from independent study

The weather data in the sample database were obtained from the National
Climatic Data Center Climatedata Volume 14.3 NCDC Summary of the Day-2.
Data from available stations were averaged by county. Discretion was used

III. Data Collection and Analysis

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