7641

• UCREFRP Catalog Number: 7641
• Author: U.S. Department of the Interior.
• Title: Quality of Water, Colorado River Basin.
• USFW Year: 1987.
• USFW - Doc Type: Progress Report No. 13,
• Copyright Material: NO

these facilities. The conflict stems from the difference in the optimum
temperatures for cold water fish like trout and warm water endemic or
endangered species like the squawfish.

In addition to downstream effects, the depth of withdrawal in
reservoirs has become a significant issue concerning the productivity of
reservoir fisheries, eutrophication, nutrient retention, salinity routing,
esthetics, and evaporation. [5] At present, there are concerns about
evaporation, temperature, and nutrient processes in Fontenelle and Flaming
Gorge Reservoirs, Lake Powell, and Lake Mead.

2. Economic

In the Lower Basin, present peak salinity is approaching critical
levels for some salt sensitive crops. While the water is suitable for
irrigating most crops, salinity is high enough that special irrigation
practices are necessary in some cases. At the present time, salinity is being
maintained below the standards. Complete development of apportioned water by
the states will result in increases in salinity that would be more detrimental
to agriculture without salinity control measures.

A consortium of water resource centers in the states of Arizona,
California, Colorado, and utah cooperated in a study funded by the Office of
Water Research and Technology and the Bureau of Reclamation to assess the
economic damages caused by various salt concentrations to agricultural and
municipal water users. This study is documented in a report, Salinity
Mana ement tions for the Colorado River, Water Resources plannin
Series Report P-78-0 3, June 978.[ ]

Based upon the findings of that report, Reclamation has published a
summary working document entitled, Colorado River Salinit --Economic 1m acts
on A ricultural, Munici aI, and Industria Users. 7 T e estlmate uture
annua amages to the Lower Basln water users in 1976 dollars were $343,000
for each 1 mg/L increase in TDS at Imperial Dam when concentrations reach the
range of 875 mg/L to 1,225 mg/L. The damage figpre is approximately $610,200
per mg/L in 1986 dollars. These annual damages were calculated using the 1972
salinity standard of 879 mg/L (approved by EPA in 1975) and a projected full
development salinity concentration of 1,225 mg/L at Imperial Dam. This study
is currently being updated, see Part IX, Economic Update to Salinity Impacts,
for a summary.

The annual municipal damages are divided as follows: Metropolitan
Water District, 54 percent; Central Arizona project, 8 percent; and lower main
stem users, 8 percent. Total agriculture annual damages are 30 percent.
Industrial impairments and Upper Basin damages were not evaluated.

3. Health

The Environmental Protection Agency, Drinking Water Office, Health
Impacts Laboratory sponsored a conference in May 1984 on Inorganics in
Drinking Water and Cardiovascular Disease. The conference was directed by Dr.
Edward Calabrese, one of the original United States researchers in the realm
of the health impacts of sodium. It was the study by Drs. Calabrese and
Tuthill concerning schoolchildren in two Massachusetts communities that
sparked the initiation of many studies around the world.

IV-4