PROJ00159

• Contract/PO #: C153305
• Contractor Name: Dolores Water Conservancy District
• Water District: 0
• County: Dolores
• Bill Number: XB 99-999
• Loan Projects - Doc Type: Feasibility Study

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Peak Consumption:

Water consumption within the district will vary dramatically over yearly, monthly,

weekly, daily, or hourly time periods. These fluctuations in flow are a function of

the momentary usage of a group of people within the district. Theoretically, maximum

demand will vary inversely with the length of time over which it is applied. This

phenomenon is documented in the American Water Works Association's Water Distribu-

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tion Training Course Manual #M8 --. Table 1.2 of the manual compares the ratio of

average consumption rates during various maximum demand periods to average annual

consumption rate for the northeast quadrant of the United States. To modify this

Table for use in the DWCD service area, the peak day usage (142% of the average day

usage) is pro rated upwards to the district's peak day usage of 300%. This figure

was established in the "Water Rate Study" prepared for the City of Cortez by KKBNA..!-Y

A graphical representation of this comparison is summarized in Figure 4-3, which

shows the peaking curve from AWWA Manual #M8 modified to conform to the assumed

peak consumption rate of the DWCD.

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Of particular interest is the peak week consumption rate which is 220% of the

average annual rate. This peak week maximum demand is the production rate at

which the district will distribute finished water to the communities and rural

areas. Consumption during shorter duration peaking periods must be supplemented

from community storage of potable water. Storage of this magnitude should be

situated within the high use areas to effectively meet the requirements during

fires and peak demand periods. By sizing the treatment and distribution facilities

of the district at the peak week consumption rate, a uniform distribution as well

as an economical relationship between treatment facilities and storage capabilities

can be achieved. The most significant result of supplying peak week as opposed to

peak day demand is the reduction in frequency and intensity of flow variations

within the treatment process,

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The Colorado Water Conservation Board has recommended that the ratio of peak day

to average day usage should range between 150% and 225%, and further, that peak

day requirements be utilized to determine maximum plant production needed. As

a facilities design basis, the peaking factor of 2.2 indicated above falls within

the Conservation Board's recommended guidelines.

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