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feet or more is reached. It therefore appears that with the floods of the main Colorado controlled by reservoirs to a maximum of 40,000 second-feet, most of the difficulties with floods below Yuma would be at an end. While existing levees would have to be maintained, especially until the Gila floods are controlled, this maintenance would be a minor matter compared with the continuous costly and strenuous undertaking that now constitutes such a burden on the lower river lands. It has been argued by some that practically nothing is gained by controlling the floods below 75,000 or 80,000 second-feet, but the experience of the engineers of the Réclamation Service in the protection of levees have shown conclusively that such a position is absurd and that the river should be controlled to a maximum discharge of about 40,000 second-feet, if at all possible.
The area in cultivation below Boulder Canyon at the present time is about 700,000 acres. It has been estimated that an additional 1,470,000 can be reclaimed, making a total of 2,170,000 acres. It has been estimated that the area now irrigated above Boulder Canyon amounts to about 1,500,000 acres and that an additional 2,825,000 acres can be reclaimed, making a total of 4,325,000 acres above Boulder Canyon.
A careful study of the flow of the river has shown that at least 8,000,000 acre-feet of storage is required for flood control alone on the lower river to regulate the floods to 40,000 second-feet, or less, and about 15,000,000 acre-feet of storage is required for irrigation. Since the river discharges about 100,000 acre-feet of silt annually a wise precaution would indicate that about 5,000,000 acre-feet should be allowed for silt storage. So that about 27,000,000 acrefeet of storage should be provided.
It has been claimed by some that the reservoirs above the canyon should be used to regulate the river for use below. This is impossible because the reservoirs in the upper river have not sufficient capacity and are situated so that they intercept only a part of the flow, leaving a large area of watershed unregulated. The Ouray site has been considered by some as a possible reservoir, but it should be eliminated as one of the Secretaries of the Interior promised in writing to dedicate this site to the construction of a railroad. It is doubtful, anyhow, if it is feasible to construct a dam for a reservoir at that point, for the foundation is very deep, and above the foundation there is a fine sand, almost a quicksand, which would make the excavation of the foundation extremely difficult, if not impossible, at any reasonable cost. The Kremmling Reservoir, that has been mentioned as a possible storage site in the upper river, already has a railroad through it. This leaves as the principal known feasible sites in the upper basin the following—and I have listed here the names of the reservoirs that Mr. Davis has already mentioned, so I will not take the time to read them but the capacity of these reservoirs is about 8,000,000 acre-feet and the estimated cost would be $40,000,000, or at least two and a half times per acre-foot as much as the Boulder Canyon site.
These reservoirs aggregate an insufficient capacity and would be relatively inefficient, as two of them, if put to use, would seldom fill for lack of water, and a third is too small to control the drainage into it. Far more important, however, is the fact that these reser
voir sites are needed for local use, for which they would not be available if operated to accommodate the needs of the lower basin, The opportunity for storage in the lower basin is larger, cheaper, and more efficient than in the upper basin. Boulder Canyon Reservoir can be built to a capacity five times as great as all the reservoirs noted in the above table combined, and at much less cost per acrefoot. If desired, it can be built to a smaller size at much less unit cost than the reservoir above named, and can later be enlarged when the encroachment of silt deposits makes it necessary.
At one time it was strongly argued by some that the best large reservoir site on the river is the one located at Glen Canyon, just above Lees Ferry, near the northern boundary of the State of Arizona. Two different dam sites were considered at Glen Canyonone 4 miles and the other 9 miles upstream from Lees Ferry. The rock at both sites is a soft sandstone, massive in structure, but made up of exceedingly fine grained quartz loosely cemented. The rock resembles in hardness the type of soft brick known as salmon brick. It crushes under shock, such as that of ordinary blasting, and small fragments can be crushed to sand between the fingers. The section of the dam is much larger than a dam for a reservoir of equal size at Boulder Canyon, and owing to the unfavorable foundation conditions in the larger section a dam at that point would cost from two and one-half to three times as much as one that would store an equal amount at Boulder Canyon.
Senator ASHURST. Considerable opinion prevails, and some of it is highly respectable, to the effect that Glen Canyon would be an appropriate place for a dam. I would be glad to have you discuss that now. Your conclusion seems to be to the effect that a dam at Glen Canyon would not be more feasible than at Boulder Canyon?
Mr. WEYMOUTH. No, indeed.
Senator AshtRST. You surely do not mean to say--and I have a high regard for your opinion--that the idea of the construction of the dam at Glen Canyon is fantastic?
Mr. WEYMOUTH. Not for a low dam; no, sir. But I think it is nearly fantastic for a high dam.
Senator ASHURST. Do you think it too far to bedrock?
Mr. WEYMOUTH. The foundation is so soft. It is like soft brick, as I have described it. For instance, I went in there with a board of consulting engineers, and we did our best to get some of the best samples. We put them in our packages, and when they were opened that stone was all sand.
Senator ASHURST. How far down did you bore? Mr. WEYMOUTH. In this particular case the Southern California Edison Co. was drilling in there, and they selected a site in the canyon walls where was located about the best rock that we could find. We shot the side wall a small charge of powder, and then we selected some for our samples of stone in that section. The stone there is not suitable to make gravel for concrete; neither would it be suitable for sand. So if a concrete dam is built there, it would be necessary to ship the material in. Now, it may be possible to find suitable material for concrete about 18 miles downstream, but even so, we would be required to build on this soft foundation. So, in my judgment, it would not be safe to build a really high đam at Glen Canyon. A low dam could be built, but it would be very expensive. Neither would this sandstone be suitable for rock filling, because it would disintegrate into a sand pile.
Senator Ashurst. For practical purposes, you seem to treat Glen Canyon dam as fantastic.
Mr. WEYMOUTH. Not for a real low dam.
Senator ASHURST. I am a layman, from the point of view of the engineer, but engineers of repute have announced that a dam could be built there.
Mr. WEYMOUTH. I have not said that a dam could not be built there, but I certainly would not build a high dam there.
Senator Ashurst. I will not pursue the matter any further at this time.
Mr. WEYMOUTH. Besides, there are apparently no suitable mate rials for a dam, either of concrete or rock-fill type. The material therefore would have to be hauled a long distance, 18 or 20 miles. The dam is inaccessible in comparison with other proposed reservoir sites. It is too far from the lands to be protected to serve adequately in the prevention of floods in the lower valley unless another reservoir is provided near the lands to be irrigated. Another very important reason is the distance of this site from the principal power markets, it being about 300 miles greater than from the Boulder Canyon. The cost of a dam at this site would be from two and a half to 'three times as much as a dam built to store an equal amount of water at Boulder Canyon.
Senator ASHURST. Have you been at Glen Canyon?
Mr. WEYMOUTH. Yes, sir. I went there in company with a board of engineers, with Mr. A. J. Wiley and Mr. Luis Hill and with Professor Ransome, the geologist. We spent some time there examining the site.
Senator ASHURST. I have a large number of well-informed constituents who may read this report, and I want them to have information about Glen Canyon as well as about Boulder Canyon.
Mr. WEYMOUTH. We have a voluminous report in the files of the committee in reference to Glen Canyon, one whole volume devoted to that subject.
Senator ASHURST. But that has not been printed.
Mr. WEYMOUTH. That is not printed. If you should have it printed, they could all read it.
Senator JOHNSON of California. When you were there, you were there for the purpose of determining an appropriate place to construct a dam, were you not?
Mr. WEYMOUTH. Yes, sir. Since storage in the upper basin or at Glen Canyon does not meet the requirements, it follows that storage should be provided below the Grand Canyon National Park. Various dam sites that have been considered from the Grand Canyon National Park, named in their order downstream are as follows: Diamond Creek, Bridge Canyon, Spencer Canyon, Devil's Slide, Boulder Canyon, Black Canyon, Bull's Head, Mohave and Parker The more important factors involved in the proper development of the entire section below the Grand Canyon National Park in the order of importance are as follows:
1. Adequate storage capacity for irrigation and flood control with a minimum evaporation loss.
2. Construction cost.
3. Maximum power output with maximum flexibility. This includes no needless sacrifices of head.
4. Minimum destruction of developed and undeveloped property.
A good reservoir site is a somewhat rare topographic feature. Satisfactory foundation conditions must exist at the dam site from the standpoint of strength, tightness, and depth. The reservoir should be large and must be tight so that the losses will be small. Other considerations are its accessibility, available construction material, and amount of evaporation from the reservoir surface. It is therefore not surprising that of the hundreds of proposed reservoir sites that have been investigated only a few are worthy of serious consideration.
Now, as to adequate storage capacity for irrigation and flood control. This factor is by far the most important, as the use of water for irrigation must take precedence over that for power in the Colorado River Basin. The object of development should be, first, the protection of present irrigated land from the ever-present dangers of inundation and water shortage, and thereafter the provision of adequate storage capacity to permit the utmost development of the water resources of the entire basin. With the further development in the Colorado River Basin the volume of storage required will increase rapidly. While a 25,000,000 acre-foot capacity reservoir is not needed for storage and flood control at the present time, it will be ultimately. That such a capacity is not needed to care for irrigation, flood control, and silt in the immediate future is apparent. The provision of this or even a greater capacity at the present time is not an economic blunder, however, as the full control of present flow for the prevention of waste and therefore the maximum power output requires the storage of more than 30,000,000 acre-feet.
Although adequate provision must be made for irrigation and flood control, any accepted plan must offer no avoidable interference with the maximum possible power development. Maximum power output is desirable, as the presence of a market in the near future for all power that may be developed below the park is generally conceded. As power depends on head and quantity of water, it follows that the maximum possible output would be obtained with stream control at the upper reaches of a section and utilization of the entire head below. As no feasible storage possibilities with sufficient capacity exist above the Boulder Canyon Reservoir site, it follows that in order to obtain a maximum product the plan adopted must be a compromise between a sacrifice of operating head and of storage capacity. The best use of Colorado River power is possible only with a large storage reserve at a strategic point that will permit a flexible power output.
In attempting to work out the best solution of the problem as a whole for the development of the river below the Grand Canyon National Park it has been necessary to make careful engineering
estimates of the cost of the several dams considered and mentioned. It may be well to advise you briefly of the information available for designing work in estimating the cost of the several sites:
For the Diamond Creek site, the topography and drilling data were obtained from Mr. J. B. Girand, applicant before the Federal Power Commission for that site.
Senator ASHURST. You are discussing the Diamond Creek site. Mr. Girand has filed an application for a license there, has he not?
Mr. WEYMOUTH. Yes, sir.
Senator ASHURST. How far is that above the Boulder Canyon Dam site?
Mr. WEYMOUTH. Something like 150 miles; I do not know exactly.
Senator ASHURST. Then the construction of the Boulder Canyon reservoir or dam would not inundate or submerge the Girand project?
Mr. WEYMOUTH. No, indeed. It would be possible to build a dam at the Boulder site to back water up to the Girand site. That could be done.
Senator ASHURST. A dam under 650 feet at Boulder, where they propose this dam to be, would not submerge the Girand project at Diamond Creek?
Mr. WEYMOUTH. No, it would not.
Mr. WEYMOUTH. I can tell you the height there. It is 690 feet in elevation—the Diamond Creek site is 690 feet at low water.
Senator ASHURST. Then the Boulder Canyon reservoir would have to be 690 feet high above low water to reach the Girand project?
Mr. WEYMOUTH. Yes.
Mr. WEYMOUTH. It would just back the water up to it. For Bridge Canyon, Spencer Canyon
Senator ASHURST (interposing). Now, as to Spencer Canyon. There is a considerable technical opinion, respectable in number and respectable in authority, which holds that a dam could be built at Spencer Canyon 1,300 feet high and divert all the water into Arizona. What do you say about that, about the feasibility and the probable cost of such a project? Are you familiar with the so-called high-line project.
Mr. WEYMOUTH. I know something about that; yes, sir.
Senator ASHURST. I should like to have your opinion as to the feasibility and cost—in a few words of the so-called high-line project at Spencer Canyon.
Mr. WEYMOUTH. I do not think it is feasible. Nearly a year ago I was one of a board of engineers that made a report to the Secretary of the Interior on that very subject, and that report is in the files of this committee, I presume.
Senator ASHURST. Is it your opinion that the high-line project is not feasible?
Mr. WEYMOUTH. Yes, sir.
Senator ASHURST. Are we to understand it is not feasible from your viewpoint as an engineer?
Mr. WEYMOUTH. No, indeed.