Centennial WSD 1996 WCPlan

• Project Type: Water Conservation Plan
• Project Name: Centennial Water & Sanitation District Water Conservation Plan
• Title: Water Management Study
• Date: 8/10/1995
• County: Arapahoe
• Water Conservation - Doc Type: Complete Plan

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3-4

In discussions with the planning staff from Mission Viejo, interpretation of the Census
data has indicated that an occupancy level of 2.78 people per household is a good planning level
estimate. District water survey results, reported in Chapter 5, indicate an average occupancy
of 2.9 per household based on the 238 surveys returned. As a result, we recommend using 2.8
people per household as an average population density instead of the figures previously cited in
earlier District planning studies and by DRCOG, ranging from 2.6 to 2.7. The District may
want to further analyze population density by incorporating future 'household surveys with water
use billings records if more accurate estimates are desired.

Residential wastewater projections should be based on 100 percent of the interior
residential water usage, or 80 gpcd. Based on simple analysis of recent data, exterior residential
usage accounts for about 46 percent of total water demand, and interior usage accounts for the
remaining 54 percent.

Data Development and Analysis

The District has produced several useful graphs displaying actual flows and demands
versus projections. These graphs are shown as Figures 3-1 and 3-2. In addition, Figure 3-3
depicts water use versus wastewater' flow, highlighting the dramatic increase in outside water
use during the wann spring, summer, and autumn months. As shown on Figure 3-4, Marcy
Gulch WWTP Hydraulic Loadings and Projections, actual flows for the plant were exceeding
existing projections.

Based on BC recommendations, District staff are collecting and analyzing water usage
data for the various customer classes. Currently, the District bills residential customers on a
bimonthly basis with meter readings taken one month for Metro District I and the following
month for Metro District 2. In order to use this data to develop water demand curves for the
residential sector, the District averages the bimonthly data reading for each Metro District and
translates it into average monthly residential use. . The District bills and_ records irri~ationand
coniriJ.eiciallfuilusfrial meterS on a monthly basis. Data curves for all of the customer classes
are shown on Figure 3-5.

The total of these three use curves provides a reasonable estimation of total water usage
that can be compared to water production. Since residential demand is based on a two-month
running average of water usage, the final demand curve will not coincide exactly with monthly
water production data. The bimonthly averaging effect will slightly affect the peaks and valleys
of the residential and total demand curves.

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