WSP09729

• File Number: 8270.100
• Description: Colorado River Basin Water Quality/Salinity -- Misc Water Quality
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1999
• Author: USDOI
• Title: Quality of Water, Colorado River Basin, Progress Report No. 19 - January 1999
• Water Supply Pro - Doc Type: Report/Study

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Causes and Impacls of Salinity

EFFECTS OF WATER QUALITY ON WATER USERS

Economic

Estimating Economic Impacts of Salinity of the
Colorado Rt\.er updated Ihe economic impacts of
salinity in the Colorado River Basin and
developed a melhod of forecasllng economic
impacts as salinity levels rise and water use
changes In the future (Lohman. et al.. 1988).
The first objective of Ihe slUdy was 10 update.
re\"be. clarify. and refine the estimales of
economic dJmages from salinil)' that had been
described in earlier studies (Anderson. el al..
1978 and Kleinman. et al.. 1980). Figure 4
shows Ihe relalive impacl of salinity on Water
users in (he Lower Colorado River Basin. The
srudy estinmed damages were 531 I million per
year based on 1976-85 salinity levels in Ihe
Lower Colorado River Basin and 1986 dollar
values. During this period. salinity averaged
767 mg/L at Imperial Dam.

The second objective of the study was (0
provide a bener means of estimating present
and future salinity damages through the
developmem of a comprehensive computer
program. While damages for 1976-85 were
estimated by the study to be S311 million per
year. as salinity levels increased to more nonnal
levels. damages (figure 5) will also increase.
SensirivIJY analysis using Ihe damage model
showed that damages (or the value of salinity
control) increase with salinilY
(U.S. Depanmem of the Interior. 1990).

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Salinity Costs by Sector

Crop (36%)

M&I(3%)

Household
(50%)

Management
(11%)

Figure 4. Sarlnlty costs by user group.

Damages vs Salinity

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$05

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400 500 600 700 800 900 10001100
Sabn<ty at Impenal Dam (m9ll)
FIgure 5,-Sallnlty damages Increase With salinity.

In 1997. the salinllY at Imperial Dam was 713 mg/l. Figure 5 shows (hat allhis level of salinil)'.
damages exceed 5500 million per year. As salinity approaches the salmity slandards levels
(879 mg/L at Imperial Dam). damages are projected to mcreas.e to about Sl billion per )'ear.
Withoul funher saliniry comrols to offset developmem. damages will increase another quaner of a
billion dollars per year.

Usinl:! J reJativeJv conservative analvsis. the bene fir of salinitv comrol was estlmaled 10 be
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S340 per ton (199-l dollar values). In comparison. the cost of saliniry control generally ranges
from S~O to SIOO per ton

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