WSP08301

• File Number: 8273.100.50
• Description: Colorado River Basin Salinity Control - Federal Agency Reports - BOR
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 2/1/1988
• Title: Estimating Economic Impacts of Salinity of the Colorado River - Final Report - February 1988
• Water Supply Pro - Doc Type: Report/Study

Economic Damages to Households... 41

Clothes washers: y = 14.42 - 0.01141 +
0.46(10-s)t2

N
--J
~
(X)

Dishwashers: y = 14.42 - 0.0114t +
0.46(1O.s)t2

An example of a regression curve is shown in
Figure 7.

While two of the regression curves are linear,
the other four curves have a curvilinear shape,
which most often took the shape of a Gompertz
or logarithmic curve, in which the useful life
decreases at a decreasing rate as TDS increases,
and approaches an asymptote representing
minimum useful life.

Other Factors Affecting
Estimates of Salinity Damages
to Households

Several complicating factors have been con-
sidered in developing the methodology to calcu-
late future household damages from salinity.

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Changes in household characteristics over time,
such as a declining number of persons per
household and an increasing number of auto-
matic dishwashers per household, must be
reflected. Changes in piping materials over time,
as permitted by periodic changes in the Uniform
Plumbing Code, also must be reflected. SliII
another factor to be considered is that some of
the "household" salinity damages occur outside
households, e.g., in commercial buildings that
have facilities and appliances similar to those in
residential buildings. Examples are: restauraut
garbage grinders and dishwashers; hotel and of-
fice building bathrooms and water heaters.
Methods for considering these complicating fac-
tors in the computer program are discussed later
in this chapter of the report.

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The method used to compute annual salinity
damages involves identifying the service Jives of
household items used under various TDS con-
centrations, then calculating the number of such
items in use in a given year in a given
metropolitan area. This equals the number of
items per household times the number of

LIFE SPAN WATER HEATERS
.
129 .
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79 ct -~
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63---------+---------+-~------+-
199.9 485.9 771.9 1957 n----
TDS .V

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x

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Figure 7. - Ute span of water heaters vs salinity level

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