WSP00818

• File Number: 8273.100.50
• Description: Colorado River Basin Salinity Control - Federal Agency Reports - BOR
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 12/1/1980
• Title: Colorado River Salinity - Economic Impacts on Agricultural, Municipal, and Industrial Users
• Water Supply Pro - Doc Type: Report/Study

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It has long been recognized that the
consumption of soap and detergents would be
greater in areas of hard water. Other costs
resulting from water hardness include treatment
for softening, wear on clothing, reduced life of
cooking utensils, and scaling of water heaters. As
can be seen in table 9, not all these areas were
analyzed in the present study. However, where
applicable, estimates from this study will be used
to update some of the previous estimates.

Household damages due to salinity have been
estimated by a number of researchers. The
Orange County and the Black and Veatch studies
are the most complete of those available (see
appendix 1 of the Andersen and Kleinman
report)." Estimates from the present study along
with estimates from the two studies mentioned
above and other available information contained
in various salinity reports have been used to
create table 10. Not all household items that
might be affected by salinity in other reports
were used because sufficient evidence was
lacking that a real detrimental effect occurs. The
individual items used were those judged to be
important and relevant to the average household
in the Lower Colorado River area. The "best
estimates" have been tabulated for each of the
three areas, resulting in a total cost per milligram
per liter of $0.1087 for the Lower Main Stem,
$0.1073 for the CAP service area, and $0.1583
for the MWD s~rvice area.

In order to calculate the estimated damages for
individual areas and for the entire Lower
Colorado River Basin, an estimate is needed of
the average annual number of households
affected by the quality of the Colorado River.
Certain assumptions and procedures were
developed for each of the three areas.

Growth projections of towns and cities along the
Lower Main St~m were derived from the most
recent two decades of population increases as
noted in the respective U.S. Census of
Population. In Las Vegas for example, where
recent population projections were available,
these estimates were used instead of the Census.
The projections of growth were discounted to
the present (1976) using 6-3/8 percent and put
on an annual basis over a 50-year period,
resulting in 250,100 households. The Las Vegas
Valley greatly influenced this annual estimate. In

10 Ibid.. pp. 41-82 (app. 1 by Jackson, Ernest S.).

addition to the Las Vegas Valley, service was
assumed to be available to Boulder City, Nevada;
Parker, Yuma, Kingman, Havasu City, and
Mohave Valley, Arizona; Needles, Blythe, EI
Centro, Brawley, and Calexico, California; and
other smaller communities. Annual detriments
for each household per milligram per liter
amount to $0.1087, which when multiplied by
the number of households, gives a total damage
for the area on an annual basis of $ 27,200.
Using the range of values given in table 10, this
value could vary from $20,900 to $46,500.

While firm numbers are not yet fUIIJ established,
a reasonable estimate suitable for the purpose at
hand for the CAP is that SOme 245,000 full
service equivalent households on a discounted
annual basis will receive Colorado River water
beginning in 1987. Household use is estimated
at 937 m' (0.76 acre-It) per household each
year. Annual detriments for each household per
milligram per liter amount to $0.1073. Total
annual detriments would be $26,300. Using a
range of values given in table 10, detriments
could vary from $20,500 to $45,600.

The MWD water from the Colorado River will be
blended with State Water Plan water with the
salinity levels eventually falling to about
350 mg/L according to current estimates. The
equivalent full service capability of the portion
of the 678 x 106 m' (550 OOO-acre-ft) Colorado
River diversion alter 1987 used by households
and the larger diversions up to that time amount
to about 1,181,000 homes on an annual basis.
It is assumed that the 1977-87 annual diversions
will be about 1.298 x 10' m' (1 052000 acre-ft)
for municipal use. Diversions will be cut back to
6 78x 106 m' (550000 acre It) per year in 1987
with 493 x 106 m' (400 000 acre-It) used for
municipal purposes. Calculations are based on
826 m' (0.67 acre-It) for each household per
year. Annual detriments for this area are
estimated to total $187,000 and the range
could be between $98,000 and $219,700.

The summary of economic impacts upon
municipal users is shown on table 11. The most
likely expected annual total for the three areas
is $ 240,500 per mg/L with a reasonable range
of from $140,200 to $311,800. A linear
function has been used to derive municipal
damages and, therefore, a constant per-unit
impact is considered for the relevant levels of
TDS.

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