that the construction and maintenance of these levees would become progressively more costly, so much so as to become infeasible, and would be unsafe even if feasible.

10. It will be cheaper in the end to rectify the river channel to the gulf and maintain it between levees than to continue present levee methods. This method would also be unsafe and would be more costly than flood protection by reservoirs.

11. The mean discharge of the river is about 22,700 second-feet. From Yuma to the gulf the river does not overflow its natural banks on a rising river until it reaches a stage of from 30,000 to 50,000 second-feet, varying somewhat, due to local conditions. While the river meanders and cuts its banks at practically all stages, levees protected with rock revetment are not endangered until a now of 50,000 second-feet or more is reached.

12. With floods controlled to a maximum of 40,000 second-feet by storage above Yuma, most of the difficulties with floods below there would be at an end. While existing levees would have to be maintained, this maintenance would be a minor matter.

13. A reservoir of 10,000,000 acre-feet capacity will be required for flood control.

14. A reservoir of 10,000.000 acre-feet capacity can be constructed at Mohave for about $26,000,000, provided foundation conditions are as favorable as at Black Canyon, which, from present information, is not thought probable (foundation conditions at this site have not yet been tested). This site is objectionable for the reason that it would flood 40,000 acres of irrigable land and about 20 miles of double track of the Santa Fe Railway and the city of Needles, a division point on the Santa Fe Railway system. It is not suited for a large reservoir as would be required for creating storage for irrigation of the area below or for creating a head for power.

15. A reservoir of 10,000,000 acre-feet capacity can be constructed at Glen Canyon for about $77,500,000. Besides this high cost this reservoir is open to the objection that it would not control the floods coming into the Colorado from large tributaries below it.

16. A reservoir of 10,000 000 acre-foot capacity can be constructed at Boulder Canyon for about $28,000,000. Such a dam could be raised later on so as to equalize the flow of the river in such a way as to admit the entire feasible irrigable area below to be reclaimed and at the same time not interfere with the development of about 4,300,000 acres of land above the reservoir. A reservoir of this capacity would also take care of the silt problem for about 100 years or more. It would be far better both from a structural and economic standpoint to construct the dam to its final height at the start and for a 34,000,000 acre-foot reservoir capacity, this can be done for about $49,500,000, or only $21,500,000 more than for a reservoir for flood control alone.

17. The advantages of this site for flood regulation, irrigation storage, and silt storage are as follows:

(a) It is readily accessible.

(b) Foundation conditions at the dam site are excellent.

(c) Construction materials of demonstrated suitability are available near the dam site in sufficient quantity for the construction of any dam considered. (d) In contrast with a reservoir at Mohave Valley it would not interfere with any proposed irrigation project.

(e) Within the limits considered estimates indicate that storage can be created in Boulder Canyon reservoir at less cost than at any other known site on the lower river, with the exception of a floor-control reservoir, which could possibly be built at about the same cost at Mohave Valley.

(f) In case of the larger reservoirs the area of water surface exposed to loss through evaporation is far less than at Mohave Valley.

(g) Is so located as to control discharge from all important tributaries with the exception of the Williams and Gila Rivers.

(h) Is the nearest to the lands to be benefited of any point on the river where it is feasible to construct a reservoir adequately providing for ultimate requirements of flood control, silt storage, and irrigation storage combined. 18. In considering the development of Colorado River, consideration was given:

First. To river regulation and flood control.

Second. To storage for irrigation.

Third. To power development.

It has been shown that river regulation, flood control, and storage for irrigation can be best and most economically obtained at Boulder Canyon with a dam at Black Canyon.

19. Any dam or reservoir constructed should fit into a general scheme of maximum practicable development for the purposes of irrigation and power. To this end sufficient storage must be provided to adequately control the floods, at first largely for the prevention of avoidable damage and later to obtain the maximum benefit from the use of such waters for irrigation and the production of power. Other considerations permitting, deep reservoirs should be chosen in preference to shallow ones, as the exposed area and consequent evaporation losses are less. Heads should not needlessly be sacrificed. 20. Numerous studies have been made of alternative power possibilities on the lower river, using several different combinations of sites. The most promising combinations of sites are set out in Table 22 of this report. The results of the studies as set out in this table show conclusively that power can be more economically developed at Boulder Canyon alone than at any other site or combination of sites, and since storage for silt, flood control, and irrigation can also be most economically developed there, it follows that Boulder Canyon is the site that should be first developed.

21. It has been shown, as set out in Table 23, on page 148, that power can be developed at less cost per horsepower or per kilowatt hour for a dam 605 feet high than for a dam with less height.

22. The Geological Survey in 1923 discovered what appears to be a favorable dam site in Bridge Canyon at an elevation of about 1,210. Should the physical conditions at this site upon test and investigation prove suitable for a dam, the interests of Colorado River development may possibly be best served by reducing the height of the proposed dam in Black Canyon from 605 feet to 550 feet.

The CHAIRMAN. Where was the dam site they discovered; what is the name?

Mr. WEYMOUTH. Bridge Canyon.

The CHAIRMAN. Where is that?

Mr. WEYMOUTH. Bridge Canyon is a short distance below Diamond Creek, I understand, 10 or 15 miles.

The CHAIRMAN. That is not the same as Spencer Canyon?
Mr. WEYMOUTH. No, sir; Spencer Canyon is farther down.

Mr. RICHARDS. Does your reference to the Boulder site have reference to Black Canyon all the time?

Mr. WEYMOUTH. It is the dam. It would cost less to build the dam at that site, for the reason that a dam 605 feet high would require about a million less feet of concrete and would give about a million more acre-feet of storage.

Mr. RICHARDS. You had reference to Black Canyon all the time? Mr. WEYMOUTH. That is true. I will repeat what I said. The Geological Survey, in 1923, discovered what appears to be a favorable dam site in Bridge Canyon at an elevation of about 1,210. Should the physical conditions at this site upon test and investigation prove suitable for a dam, the interests of Colorado River development may possibly be best served by reducing the height of the proposed dam in Black Canyon from 605 feet to 550 feet. The storage capacity would thereby be reduced from 34,000,000 acre-feet to 26,000,000 acre-feet, and with adequate allowance for the needs of irrigation and flood control in both cases the possible continuous power output would be reduced from 667,000 horsepower with the higher dam to 550,000 horsepower with the lower dam. The cost of the dam would be reduced from $49,500,000 to about $41,500,000. With a load factor of 55 per cent, the 605-foot dam would permit a development of 1,200,000 installed horsepower at a total cost of construction for dam, power house, and primary transmissin lines

of $131,000,000 or $109 per horsepower, while the 550-foot dam would permit a similar installation of 1,000,000 horsepower at a total cost of $111,000,000 or $111 per horsepower. While power can therefore be produced cheaper with the 605-foot dam than with the 550-foot dam, the cost, even with the latter, is very reasonable. !Reading:]

23. Dams at Bridge Canyon and Black Canyon and a regulating reservoir at Bullshead, where considerable power also be produced, would utilize the head from Grand Canyon National Park to Needles to the highest degree attainable and in the most economical manner to efficiently regulate the river in this section to the fullest extent for flood control, irrigation development. and power without interfering with upstream developments.

24. The report also shows that there is a market capable of absorbing within a period of seven years after completion of the dam the power output of a plant with a capacity of 1.200,000 horsepower with a 55 per cent load factor or 667,000 continuous horsepower and at a price that will return the entire cost of the Boulder Canyon development.

25. It therefore appears that the solution of the immediately urgent problem of the Colorado Basin, with due regard to future development, is comprised in(a) The construction of the Boulder Canyon reservoir with a dam in Black Canyon raising the water surface 605 feet and forming a reservoir of 34,000.000 acre-feet capacity, with a possible alternative as described in paragraph 22. (b) The reservation of 8.000,000 acre-feet capacity at the top of this reservoir for flood control, this reservation to be decreased in amount finally to 4,000,000 acre-feet as development upstream may justify.

(c) The provision of priority for irrigation use over power development for the remaining storage.

(d) The construction of a power house with 1,200,000 horsepower installed capacity with necessary transmision lines and other equipment, with a possible reduction to 1,000,000 horsepower, as described in paragraph 22.

(e) The construction of the all-American canal from Laguna Dam to Imperial Valley.

That concludes the synopsis.

Mr. HAYDEN. The figures you gave of the area in the upper basin and the area in the lower basin are somewhat different from the figures in the Davis report on the Imperial Valley. I notice that you have increased the possible irrigable area in the upper basin from 4,000,000 to 4,325,000 acres. Is that as a result of later studies of the irrigable area in the upper basin?

Mr. WEYMOUTH. Yes. We have, in each State, secured as much information as we could from the State officials and State engineers. Mr. HAYDEN. Do you find the tendency on the part of the State engineers to see new areas, new projects, new possibilities, as time goes on in each State?

Mr. WEYMOUTH. There is a tendency in all the States to fix up their estimate of the areas as large as they possibly can; yes, sir.

Mr. HAYDEN. If there were 4,325,000 acres irrigable in the upper basin and under the Colorado River compact there were allotted to them seven and a half million acre-feet of water, would that quantity of water be sufficient for all purposes?

Mr. WEYMOUTH. Yes, sir.

Mr. HAYDEN. More than sufficient?

Mr. WEYMOUTH. I think it would be sufficient. There would be a large return flow from that upper country that would come back into the river that could be utilized below.

Mr. LEATHERWOOD. You mean used in the upper basin the second time? Do you mean, Mr. Weymouth, that there would be a return flow, after the water had been taken out on the land, back into the

river, back into the basin, so that it could be diverted a second time into the upper basin?

Mr. WEYMOUTH. There might be at some times, in some cases, yes; but there would be a great deal of the return flow that could not be used in the upper basin, that would come into the river too low down, and it could only be used in the lower basin.

Mr. LEATHERWOOD. The thing that interested me was whether there would be a return of the flow back into the upper basin.

Mr. WEYMOUTH. It could be picked up again and used in the upper basin to some extent.

Mr. HAYDEN. The allocation of the water under the compact is not based on water diverted from the stream, but the net consumptive use, accounting for the return flow.

Mr. WEYMOUTH. Yes, sir.

Mr. HAYDEN. And you are satisfied that the amount allocated for the upper basin for this area of land is ample for all purposes? Mr. WEYMOUTH. I think so; yes, sir.

Mr. HAYDEN. In the lower basin, you stated there was a possible area of irrigation above the Laguna dam, of 469,000 acres, and, below Laguna dam, 1,699,000 acres. That makes a total of 2,168,000 acres, as compared to a total of 2,020,000 acres in the Davis report, again indicating that you found additional areas that might be irrigated in Nevada, Arizona, and California, which were not included in the original report. Does that figure include anything for lands in Mexico?

Mr. WEYMOUTH. Yes, sir; 800,000 acres.

Mr. HAYDEN. You still abide by the original estimate of 800,000 acres in Mexico?

Mr. WEYMOUTH. Yes, sir.

Mr. HAYDEN. Have you made any effort to check up the lands in Mexico that could be irrigated?

Mr. WEYMOUTH. No, sir; not since the last report.

Mr. HAYDEN. So your estimate is based on the same assumption and not upon any new investigation?

Mr. WEYMOUTH. No, sir.

Mr. HAYDEN. Taking up the various power sites: As I understand it, you recommend the construction of a dam at Black Canyon, to create the Boulder Canyon reservoir?

Mr. WEYMOUTH. Yes, sir.

Mr. HAYDEN. And that at an estimated cost of $49,500,000?

Mr. WEYMOUTH. $49,500,000.

Mr. HAYDEN. That is for a 605-foot dam?

Mr. WEYMOUTH. Yes, sir.

Mr. HAYDEN. There has been some talk of the so-called Kelley site in that same region. I understood it to be a reservoir site discovered or recommended by Colonel Kelley, of the Federal Power Commission. Have any borings been made at that site?

Mr. WEYMOUTH. I have just been on a board with Colonel Kelley for several weeks, and I never heard of the Kelley site.

Mr. HAYDEN. It was mentioned by Mr. Ballard, of the Southern California Edison Co. He stated, that if his company were given permission to carry out its plans with respect to the Colorado River, he was of the opinion the Kelley site would be utilized. Mr. SWING. Maybe he meant the Kelley plan?

Mr. HAYDEN. No; he talked about the Kelley reservoir site on the Colorado River, between Black Canyon and Boulder Canyon. Mr. SWING. I think the Kelley plan and the Edison Co.'s plan are very close together.

Mr. HAYDEN. That is beside the question. You stated that the cost of a similar reservoir at Glen Canyon would be $77,000,000: Mr. WEYMOUTH. No. That would be for a reservoir of only 10,000,000 acre-feet capacity, $77,000,000. It would be a much smaller reservoir.

Mr. HAYDEN. Have you any estimate of the cost of controlling the floods of the river at Glen Canyon?

Mr. WEYMOUTH. Just to control the floods?

Mr. HAYDEN. Yes.

Mr. WEYMOUTH. $77,500,000.

Mr. HAYDEN. How much would it cost to control the floods and store the water for power and irrigation at Glen Canyon in the same manner as at Boulder Canyon?

Mr. WEYMOUTH. $126,500,000.

Mr. HAYDEN. That would be a dam how high?

Mr. WEYMOUTH. 605 feet.

Mr. HAYDEN. How do you account for the tremendous difference in price between dams, equally high, the one at Boulder Canyon $49,500,000 and the other at Glen Canyon, $126,500,000?

One is the dam site

Mr. WEYMOUTH. There are several reasons. at Glen Canyon is much larger, that is, much wider; therefore, requiring much more concrete in the dam. Another reason is the foundation conditions there are very different than in Black Canyon. It is very soft sandstone in Glen Canyon; in fact, it is as soft as a very soft brick, and our consulting engineers advised in that particular case that they would not recommend foundation pressures of more than 20 tons per square foot; but this estimate I just gave you of the $126,500,000, was for a dam of 30 tons pressure. And our engineers would not recommend a dam there with that

pressure.

Mr. HAYDEN. What did you find the difference to be in the depth of the bedrock at Black Canyon and at Glen Canyon?

Mr. WEYMOUTH. At Glen Canyon we did not have very many holes; they only put down three, I think, in the river and, if I remember correctly, the depth was about 80 feet; but the site was not well enough tested to definitely prove whether that was the deepest point in the river for that dam site or not.

Mr. HAYDEN. What is the deepest drill hole in Black Canyon? Mr. WEYMOUTH. One hundred and twenty feet. But there we put down a great many more holes and really developed the foundations, so that we know what the depth to foundation is.

Mr. HAYDEN. Has any dam been built anywhere in the United States with so great a depth to bedrock?

Mr. WEYMOUTH. Not to my knowledge; but at Arrowrock a dam which was constructed under my charge we went down over 100 feet. Mr. HAYDEN. Did you have any difficulty in combating the water pressure at that depth?

Mr. WEYMOUTH. No: not serious.

Mr. HAYDEN. Do you consider that that additional depth at Black Canyon could be as easily overcome as the 100 feet at Arrowrock?