WSP04095

• File Number: 8270.100
• Description: Colorado River Basin Water Quality/Salinity -- Misc Water Quality
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1987
• Author: USDOI
• Title: Quality of Water - Colorado River Basin - Progress Report No. 13 - January 1987
• Water Supply Pro - Doc Type: Report/Study

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near Las Vegas, Nevada. The study will establish the in-plant costs of using
brackish water from the Lower Virgin River as compared to alternative
supplies. Opportunities for cost sharing further studies and construction of
a water supply system for the proposed (1996) powerplant will be pursued with
Nevada Power Company. Test results from the Etiwanda study will be
incorporated into the process concepts proposed for the Harry Allen Plant.

Aquaculture.--International 8io Resources, Inc. and Denver
Engineering Corporation completed a contract study for the use of a Salt
Tolerant Emergent Plant (STEP) process to beneficially use, concentrate, and
dispose of saline water. Economics of the STEP process were applied to the
Glenwood-Dotsero Springs Unit. Although unit costs under $100 per ton were
claimed in the study, technical issues related to production rate, evaporation
rate, forage value, etc., could not be addressed due to lack of field
experience. Moreover, remaining questions related to beneficial use and water
rights of Glenwood Springs, coupled with lack of government funding for
continued research, have halted the study effort.

20. San Juan River Unit (Reclamation)

The San Juan River Unit investigations began in November 1985 with
the objectives of locating salt sources and identifying control methods. The
study area includes the entire 23,OOO-square-mile watershed from its
headwaters in south-central Colorado to its mouth at Lake Powell. The
drainage contributes approximately one million tons of salt annually to the
Colorado River Basin. Early reconnaissance shows significant salt loading in
the river between Shiprock, New Mexico, and the Four Corners. At Bluff, Utah,
the annual flow of 2,047,000 acre-feet of water contains 1,165,000 tons of
salt. About 18 percent of this salt loading occurs between Ship rock and
Bluff, but only 7 percent of the water is added in this reach.

The study area was broken into about 20 sub-watersheds and
geographic areas. Since November 1985, water quality sampling and flow
measurements throughout these subbasins have been made to gain an
understanding of salinity mechanisms. The study area covers many thousands of
square miles of natural resource lands as well as agricultural, municipal and
industrial areas which may contribute controllable salt. Most of the natural
source of salt is contributed by surface runoff and ground water discharge
from the Nacimiento Formation and Mancos Shale. Many thousands of acres of
vegetation, along the streams and washes, worsen the conditions by
concentrating the salts. Irrigation projects, coal-fired powerplants, surface
mining operations, oil and gas fields, and refinery operations also contribute
to the salinity problems.

The sparsely vegetated Mancos Shale and Nacimiento Formation
badlands, covering much of the Basin, contribute large amounts of sediment and
salinity particularly during summer thunderstorms. The Mancos Shale is also
the source of saline springs and ground water.

This shale is exposed to the river's alluvium from the hogback,
almost 30 miles east of Shiprock to just upstream of the confluence with the
Mancos River near Four Corners. The Mancos River cuts across the Mancos Shale
for about 25 miles before entering the San Juan River.

The Hammond Project, Navajo Indian Irrigation Project (NIIP), and
the Hogback Irrigation Project (also a Navajo Indian project) are the

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