Vol. 6, No.3
Final EIS Filed on Grand
Valley Unit
Reclamation is completing final activities before issuing specifications and awarding a contract for the first phase of Grand Valley Unit Stage Two
construction.
The final environmental statement was filed with the Environmental Protection Agency in May 1986. Once a decision is made to construct Stage Two, we make a contract award, scheduled for September 1986, that involves membrane-lining approximately 7 miles of the Government Highline Canal in a portion called the west end.
The canal extends from the end of the canal segment lined under Stage One to the canal's terminus approximately 6 miles northwest of Mack. Replacing or improving farm and lateral turnouts and other canal structures is also part of the canal improvement project expected to be completed in 1988. The next portion of the Stage Two plan will replace with pipe laterals approximately 36 miles of open-earth laterals served by the west end portion of the Government Highline Canal.
The entire Stage Two plan provides for membrane-lining a total of 38 miles of the Government Highline Canal and replacing a total of 308 miles of existing laterals with pipe. The membrane lining would be 20-mil polyvinyl chloride covered with 14 to 19 inches of earth and gravel.
CrosJ-drainage features will be constructed and would include detention ditches and dikes. Four detention dams would be used to create small
impoundments for leveling out streamflows in natural drainages. Two automated moss and debris removal structures will also be installed.
Measures are also included in the Stage Two plan to compensate for wildlife habitat losses that result from increased development from the entire Grand Valley Unit. Construction costs for the entire Stage Two plan are estimated at approximately $190 million. Salt loading to the Colorado River will be reduced by
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U.S. 'Department of the Interior
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Colorado River Water Q(lality
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July 1986
This wooden bridge across the west end portion of the Government Highline Canal, located west of Mack, Colorado, in Mesa County, is typical of other bridges which will be replaced as part of Stage Two development of the Grand Valley Unit.
Approximately 308 miles of unlined Government Highline Canal laterals will be lined with buried pipe as part of Stage Two development. This photograph was taken in the winter of 1982 during Stage One construction.
approximtely 143,500 tons annually, with an estimated cost effectiveness of approximately $89 per ton.
Stage One development, completed in April 1983, included concrete-lining 6.8 miles of the Government Highline Canal and constructing numerous cross-drainage features. In addition, 13 open earth laterals were consolidated into 12 pipe laterals. A moss and debris removal structure was placed at the beginning of the improved portion of the canal.
San Juan River Unit Studies
Progressing
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 23,000 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 system.
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 Shiprock 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, 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 that 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
Salt discharge from abandoned well.
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 total
dissolved solids (TDS) 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, just east of Shiprock, for about 30 miles 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 Project (also a Navajo Indian project) contain the principal irrigation sources of salt in the basin. Preliminary canal seepage and drainage investigations have been made on the Hammond Pro-ject and justify the need for more detailed testing. Historic flow and water quality data from subsurface drains show that the irrigated area contributes about 18,500 tons TDS annually.
The NIIP irrigated area has recently
started discharging water above 3000 mg/L, mostly in the Gallegos and Ojo Amarillo Washes. These are both wide and deep sandy washes and the drainage water could be collected in them
if disposal or industrial-use alternatives appear feasible.
The Hogback Project contributes heavy salt loading but the mechanisms have not yet been explored. Ground water accruing to the San Juan alluvium in this vicinity shows TDS concentrations of over 15,000 mg/L. Other manmade salt
contributions include abandoned gas or oil wells that have developed leaks at the wellhead, coolant discharges from powerplants, and wastewater from a petroleum refinery.
As the information in this early stage of investigation is gathered, potential solutions are being developed. Costs for lining the canals in the area are being estimated, methods of controlling the salt discharge from those areas north of the river are being identified, and potential industrial users will be contacted. Envi-ronmental and other planning
considerations, such as water rights, are being evaluated.
The conclusions from this appraisal of the basin will be made by this fall. If at least one cost-effective and acceptable alternative can be identified, the study will continue toward identifying the best plans for reducing salinity in the basin. A planning report and environmental docu-ment is scheduled for the fall of 1989. Questions or comments on this study can be sent to the Durango Projects Office, U.S. Bureau of Reclamation, P.O. Box 640, Durango, CO 81302 or by phone at (303) 385-6500.
Hybrid Grass May Help
Reclaim Salt-Laden Land
Reprinted from the Journal of Soil & Water Conservation, May-June 1986, Vol. 41, No. 3.
A hybrid grass grown for livestock feed also acts as a soil cleanser and could help reclaim millions of acres of salt-laden soil in the West, according to an Agricultural Research Service scientist.
Salt, or sodium, that accumulates in soil can form a crust on the soil surface, impeding crop growth. But the new grass, a cross of sorghum and sudan-grass, releases a high level of carbon dioxide into the soil, which frees the salt so that rainfall or irrigation water can leach the salt out of the soil, according to Soil Scientist Charles Robbins of Kimberly, Idaho.
The hybrid grass grows to 11 or 12 feet and produces about 25 tons of grass per acre. It is drought-resistant and can be used for livestock feed and silage in low rainfall areas. Robbins' studies indicate the grass could be used to reclaim millions of acres of salt-bound soils in the arid West, parts of the northern Great Plains, western Canada, and similar regions throughout the world.
In one test, on a soil so high in sodium content that no crop of value could be grown, the grass averaged 20 tons per acre.
The grass, says Robbins, might also help cut costs of applying gypsum to reclaim soil. In irrigated regions farmers must apply 10 to 20 tons of gypsum per acre at a cost of $65 to $70 a ton. "We
are getting surprisingly better results by
planting the hybrid grass than we got by
applying gypsum," Robbins said.
Visitors Tour Grand Valley
Stage One
On April 15, 1986, 22 people from India were given a field review of Stage One, the completed portion of the Grand Valley Unit, Colorado.
The Indians are touring the Western United States to study waterlogging, drainage, and salinity control. One report estimates that 35 percent of India's irrigated land is seriously saline.
Tracking Salty Soil
Excerpted from an article by Dennis Senft, Albany, California, in the publication Agricultural Research, U.S. Department of Agriculture, Agricultural Research Service, January 1986.
A pickup truck pulls off the highway and stops. A high school student gets out, removes a probe which is attached by wires to a backpack data recorder, swings the equipment over his back, and walks about 100 yards into an adjoining field. There he shoves the probe six inches into the soil and pushes a button to automatically record soil salinity and exact location in the field.
When several hundred such measure-ments have been recorded, the young employee returns to the local irrigation manager's office and electronically transmits the information into a
computer. The computer, no larger than some home models, analyzes the information and prints a map that indicates areas where yield-reducing salts are accumulating in farmers' fields.
Agricultural Research Service scientists have developed the measuring probe, now commercially available, and the computer programs. They are now evaluating ways to make the large-scale collection of data
economical, perhaps much like the
tech-nique portrayed above.
The USDA's Soil Conservation Service has contributed $100,000 this year to help make such soil salinity mapping possible.
California has 8.6 million acres of irrigated land and about half, 4.5 million acres, is affected to some degree by
salinity. Similar problems are occurring throughout the western United States. One report estimates that 35 percent of India's irrigated land is seriously saline and that one-quarter to one-half of South America's irrigated acreage is adversely affected by salts.
"Estimates are educated guesses," says Jan van Schilfgaarde, former director of the U.S. Salinity Laboratory, Riverside, CA, "but until we develop ways to monitor the degree of increasing salinity, I won't argue with anyone who says we have a very serious problem both here and overseas."
Long-term corrective action is needed to protect irrigated agriculture, but first we need to be able to detect the onset of problems and to predict where they will occur," says ARS soil scientist James D.
Rhoades, Riverside.
Rhoades says salinity measuring is currently done in laboratories, and each sample can cost up to $25 with several dozen needed for each field. Such expense is prohibitive for mapping large areas.
"The sampling technique and maps we are developing will eliminate the major need for soil sampling and laboratory analysis. Cost figures haven't been calculated yet, but if we can get the system automated, it should cost a mere fraction compared with present tech-niques."
Maps that minimize the need for direct measurement use computer overlay tech-niques and can be likened to maps in some geography text books. Geographic features are printed on one page and additional information, such as how boundaries have changed over time, is printed on individual overlays made of clear plastic.
In this case, each overlay contains information on one factor that can contribute to salinity in soil.
These factors include water table depth, soil permeability, leaching fraction (the amount of excess irrigation water applied to leach salts below the root
zone), and ground-water salinity. A
composite of these factors defines areas of probable salinity development.
Several thousand pieces of information
can be entered into the computer for each map. Then computer programs
written by Dennis L. Corwin, formerly
with ARS, manipulate the information.
The programs analyze values assigned to each salinity factor. When these values exceed an assigned number, the computer indicates a potential trouble area. Armed with these maps, farmers and growers will be able to locate areas on their land where salt problems are likely
to occur. They can then change the way
they farm to avert or reduce damage. Such damage, unchecked, would not only put farmers out of business, but could
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permanently destroy the agricultural productivity of the land.
Government agencies will be able to use the maps to anticipate the extent and degree of future salinity problems and formulate policy.
Land use planners will be able to find best locations for industrial, commercial, and housing needs, locating these on more salt prone areas.
Rhoades developed the measuring probe which contains four electrodes. An electrical current flows through the soil-passing between the outside pair of electrodes. A meter indicates how much resistance the current flow encounters-a direct indication of salinity. Each poke of the probe measures a soil sample roughly 6 inches deep and· 6 inches in diarr.eter.
Rhoades is also using a salinity monitor tha1 may make measurements even easier. It consists of a generator that produces an electromagnetic field that emanates invisibly from a 3-foot-long bar. This field causes an electric current flow within the soil that is proportional to salinity. With such electronic measuring devices, Rhoades determines how salty the soil is. As soil salt increases, the secondary current flow increases proportionally.
"I don't even have to lay the monitor on the soil. It gives a correct reading when suspended at hip height. And by rotating the magnetic field, I can determine salinity at specific depths."
"The ideal measuring device might be some form of this electromagnetic measurer. It is possible, in principle, to mount it on an all-terrain vehicle or even suspend it from a low-flying aircraft. This would dramatically reduce the time and labor needed for data collection," Rhoades says.
"We're fairly confident with our present measuring devices and computer programs. Our biggest challenge will be matching our data with exact locations where we collected it," says Rhoades. He envisions someday using portable "direction finders" capable of receiving LORAN-type navigational radio beams either directly or relayed via satellite stations. Such systems are used commercially to aid ocean vessels and
aircraft in routine navigation and to locate them in emergencies.
Joint Reclamation-SCS
Price-San Rafael Rivers Unit Study
to Proceed
Reclamation and SCS (Soil
Conservation Service) have been studying the potential of a combined Reclamation-SCS plan for reducing salt loading to the Colorado River. The plan would be pressurized sprinkler irrigation combined with watering troughs for livestock thereby eliminating seepage from
stockwater ponds.
The incremental cost of the combined plan for Reclamation was greater than $100 per ton; therefore, the information was presented to the Colorado River
Basin Salinity Control Forum's Work
Group for their analysis and recommendation.
A report prepared for the Work Group summarized the efforts of SCS and Reclamation and the costs associated with these plans. The total costs of the combined plan was approximately $70 per ton of salt removed, and the amount of salt that could be prevented from entering the river system was more than with either of the separate plans. The
Work Group, therefore, recommended
that Reclamation and SCS continue with the studies of the combined plan.
Contract Awarded for Salinity
Damages Update
Award of contract was made in June for updating the economic study made earlier by Alan P. Kleinman and F. Bruce Brown, Colorado River Salinity -Economic Impacts on Agricultural, Municipal, and Industrial Users in
December 1980.
A Denver firm, Milliken, Chapman Research Group, Inc., has been awarded a six-month study contract to update salinity damages in the municipal and industrial sector for the major water users in the lower Colorado River Basin.
Wyoming Farmers Favor
Low-head Sprinkler Plan in Big
Sandy River Unit
At a public meeting April 2, in Faron, Wyoming, the SCS (Soil Conservation Service) presented their selected low-head sprinkler plan to reduce salinity in the Colorado River system. Although SCS does not have funding to implement the plan at this time, they wanted to determine if sufficient support was available for the proposed plan to
warrant completing their report. If
funding became available, the plan could
then be implemented.
The local farmers generally favored the
SCS plan. An update of Reclamation
activities was also provided to the group. The update included (1) a brief
explanation of ponding tests to determine canal and lateral seepage rates and (2)
other field activities that are being conducted this spring, summer, and fall.
Dirty Devil River Unit Studies
Suspended
Advance planning studies have been delayed at the request of the Colorado River Basin Salinity Control Forum. The inability to secure water rights from the State of Utah was the stated reason for the delay. All advance planning will be suspended until further notice.
The recommended plan was to collect saline water by pumping from shallow wells and then disposing of the flows by deep well injection.
Report Available from
Conservation Foundation
A report entitled The Salty Colorado has been published by the Conservation
Foundation and the John Muir Institute.
Copies are available by writing Lydia Anderson, Sales Manager, The Conservation Foundation, 1255 23rd Street NW, Washington, DC 20036 or by calling her at (202) 293-4800. The price per paperback book is $9.50 plus $1.00 ($2.00 minimum) for shipping and handling. Bulk order discounts are available.
Editor: Patty J. Gillespie
Salinity Update is published 4 times per year by the Colorado River Water Quality Office, Bureau of Reclamation, Department of the Interior, in cooperation with other Interior agencies, the Department of Agriculture, and the Colorado River Basin Salinity Control Forum.
United States
Department of the Interior Bureau of Reclamation D-10<Xl
P.O. Box 25007 Denver Federal Center
Denver, Colorado 80225-0007
OFFICIAL BUSINESS
Questions concerning the program or specific projects should be addressed to:
Colorado River Water Quality Office Bureau of Reclamation, D-1000 P.O. Box 25007
Denver, Colorado 80225 Telephone: FfS 776-6782 Commercial: (303) 236-6782
When writing to request address changes or deletions, please include a recent address label. Contributions to the newsletter are
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