power is equal to the head times the quantity of water, in cubic units, multiplied by the weight of the cubic unit divided by a constant in order to determine your answer in proper units. That is in English units, the horsepower is equal to head times the number of cubic feet of water per second times the weight of a cubic foot of water divided by a constant, in this case 550 times the efficiency of the installation, which gives the power development.

Representative JENKINS. I just want to know for my own information, it wouldn't be safe to say that the power is proportionately in line, in proper ratio, with the head. Volume is more important than the head, the volume back of the dam is a factor, too, because it would be perfectly easy to have one dam with a head of 100 feet, on a shoal, and the volume back of it wouldn't be very much as compared if it were a more gradual grade, where the lake would be back of it 20 miles in one case, and in another case only 1 mile.

Colonel PARKER. That volume affects the storage only and it wouldn't affect the power which is the product of the head and flow only. As long as you have a certain head, a certain quantity of water flowing, it will produce a definite amount of power.

Representative JENKINS. Regardless of the lake, the height of the lake is the only important factor, and not the amount?

Colonel PARKER. As far as the amount of power generated and the amount of energy you can store is dependent upon the size of the lake. Mr. BIDDLE. Give two or three more of those, and then we will offer it as an exhibit.

Colonel PARKER. Jackson Bluff, which I believe is in Alabama.
Mr. BIDDLE. Private?

Colonel PARKER. A privately owned plant. Has a head of 33 feet and cost $333 per kilowatt.

The Wyman Dam, which is in Maine, on the Kennebec, privately owned, head of 139 feet, cost $195 per kilowatt.

The Conowingo Dam, which is privately owned, is in Maryland, a very large development. Has a head of 89 feet, and cost $197 per kilowatt.

Safe Harbor Dam, on the same river, on the Susquehanna just above that, has a head of 55 feet, and cost about $152 per kilowatt.

Then, some of these, just to indicate what the effect of head is, the plant at Waterville, which is privately owned, has a head of 860 feet, and cost only $128 per kilowatt, a much higher head.

Some of these western plants with extremely high heads run down to such figures, but in general, any plant having a head less than 200 feet, if it costs less than $200 or less than $175, is rather phenomenal. Mr. BIDDLE. This exhibit, which I will now have marked for identification, contains a list of certain hydroelectric plants, on which is also noted the head in feet and the total cost per kilowatt capacity, is that correct-and that is taken from an article of H. K. Barrows, Hydro-Generated Energy-the proceedings of the American Society of Civil Engineers, in April 1938, from figures of the Federal Power Commission, which you will later have.

Would you mark this?

(Whereupon the document above referred to was received in evidence and marked "Exhibit No. 496.")

COMMENTS ON ENGINEERING WORK OF AUTHORITY

Colonel PARKER. Now I should like to introduce certain exhibits to illustrate the way really in which our work is carried on. I think that it will illustrate also several other things. It will illustrate the character of the work, and also the way in which our construction costs are controlled and handled, and analyzed.

I first would like to introduce a few exhibits indicating the way the different departments, an example of the way they handle the work. I have already shown one exhibit, showing the flood area in Chattanooga.

The chart marked "No. 4" in this folder, that shows the character of the lower Mississippi Valley, and I rather hesitate to introduce this because we don't want to get involved in a detailed discussion of the lower Mississippi Valley. I simply show it to indicate that we have given some thought to this and to the prevalence and character of the floods down there and to various areas involved.

We have had an engineer make a report on the effect of our flood regulation on the lower Mississippi.

Mr. BIDDLE. The top of that is Cairo, and how near to Cairo does the Tennessee Valley come into the river?

Colonel PARKER. Our Gilbertsville Dam is located right here near the mouth of the Tennessee, which I believe is something less than 50 miles from Cairo, and that, by the way, is less than 1 day's journey by water, that is the flow of the river, the water in the river requires only a day to pass from the site of Gilbertsville Dam to the mouth of the Ohio.

Mr. BIDDLE. And the bottom of the chart is New Orleans, I take it. Colonel PARKER. New Orleans is here.

Mr. BIDDLE. Do you know how long the navigation takes from New Orleans to Cairo? I meant boat travel; I didn't mean water flow.

Colonel PARKER. About a week.

Representative JENKINS. Let me ask a question about that, Colonel. You don't claim that anything that is done or will be done on the Tennessee River, by T. V. A., will have any appreciable influence on the floodwaters of the Mississippi River?

Colonel PARKER. We estimate that the regulation afforded by our proposed Gilbertsville Reservoir will lower flood crests at Cairo by at least 2 feet, from 2 to 21⁄2 feet, those flood heights on the Ohio and Mississippi at that point.

Representative JENKINS. I have here before me-do you know the name of the gentleman, the river expert, representing the Mississippi River Association, that testified in these trials?

Colonel PARKER. Major Putnam?

Representative JENKINS. No; not Major Putnam.
Mr. BIDDLE. Mr. Kurtz?

Representative JENKINS. No; I think he is president of the Mississippi River Association, or something like that. He was a witness and testified-I would like to have permission to furnish his testimony, a few lines in the record, at this point, and I can't find it here, but I can find it.

Chairman DONAHEY. You may proceed.

Colonel PARKER. Shall I proceed with chart No. 6, indicated here?

The next exhibit is labeled No. 5, in my records, and is the report on the Chickamauga project, which was compiled by our planning department, preliminary to the development of that site. It is offered as an example of this character of work; it is an example of the investigation carried on prior to the actual authorization of construction.

Mr. BIDDLE. Would you mark that, please, as "Exhibit 497?" (The document above referred to was received in evidence and marked "Exhibit No. 497.")

Mr. BIDDLE. Describe that very briefly.

Colonel PARKER. It is the result-it shows the results of the investigation which was made by the planning department to determine the proper site for this development. The general character of it, the height of the dam, amount of power to be installed, and general characteristics of the construction.

Those depend or result from a good deal of basic data acquired in the way of surveys, borings at the site, stream flow gages, and calculations of various kinds, which has to be extremely thorough in order to insure a project of this magnitude being carried out in the proper

way.

There is also a great advantage in setting up such results in this form where it affords a permanent record of our work, and a means of ready reference from all those interested in the project. It does not necessarily contain the exact dimensions of the structures as finally built; it is a guide; after approval by the Authority, by the board of directors, and authorization of the project, such a report is passed to our design department, and serves as a guide for them in developing the detailed and practical designs for the dam.

Mr. BIDDLE. Would that be a guide of estimated costs?

Colonel PARKER. It accompanies and includes an estimate of the cost of the project and in that way forms a basis for the request for authorization and for funds which we make to Congress.

Mr. BIDDLE. All right. Thank you.

Colonel PARKER. The next exhibit is labeled No. 9 in our list, chart No. 6.

Mr. BIDDLE. That is found in the exhibit which the committee already have, 494.

Colonel PARKER. This is an example of the work of our design department, to indicate in a general way what the structures look like in cross section. This figure on the left is the cross section through the Hiwassee Dam and is typical of the high dam type of project.

You will see that it shows an operating deck up here, for regulating overflow and sluiceways down here to permit the discharge of the waters which are below this crest in the event that we wish to lower the reservoir level in anticipation of flood in order to provide sufficient volume up here.

You will notice this extensive apron, so-called, plunge basin, which is devised to use up the energy of the falling water so that it won't tear away the rock below the dam and undermine the dam structure. The shape of this thing is developed in our hydraulic laboratory very carefully on models.

This diagram bere shows a typical main river dam which as you see is very different from the high dam on tributaries. It consists of a lower block of concrete with an apron to absorb the energy and high piers, which are in the case of most of our dams, about 40 feet apart, the space between these piers is occupied by large steel gates, which are ordinarily about 40 feet high, and 40 feet wide, made in two sections, which can be raised by suitable arrangement on the operating deck so that in time of floods all that is left of this structure is the sill and the piers, that you see is necessary because the volume of water which we have to contend with in the main river is so much greater than it is on the tributaries. In addition

Representative JENKINS. One question there. That doesn't mean that you let down all--you don't let down the gates; all of the gates in the dam, or you wouldn't have any left for power.

Colonel PARKER. The normal procedure is to raise enough of the gates to permit passage of the amount of water which is flowing or desired to pass and maintaining this water level at the desired elevation. We are able to control the flow entirely in this manner.

This depth of gate-they are very large, this is a very large struc

ture.

Representative JENKINS. The water would go over the top; it did go over the top of Chickamauga about 8 feet once?

Colonel PARKER. Over the sill, but that was this point here; that is only up to the elevation of the framework.

Representative JENKINS. Am I mistaken about this, that the last flood that you had in the Chickamauga section down there went clear over the top of some of the construction?

Colonel PARKER. We had certain floods which overflowed our cofferdams, but our cofferdams are merely temporary structures which are used to unwater only, and they bear no relation to the height of the permanent dam.

These gates have this unusual depth largely for the purpose also of being able to draw these reservoirs down in anticipation of a flood. We might have designed a longer spillway, with a higher crest and shallower gates, but that would not permit the reservoir to be down in anticipation of a flood. It requires that additional depth so that as the water rises, it doesn't rise up to a flood height and fill the floodcontrol storage.

Mr. BIDDLE. All right, the next one.

Colonel PARKER. Next is chart No. 7, which is shown merely as an illustration of what design work really is. Of course, for any particular project, something like 800 or 1,000 drawings are made of all sorts of details. Now, one of such drawings is this cross-section through a powerhouse, taken in this instance through the generating unit, which is here, and the headwork structure is here, and here is the water wheel and generator and this is a photograph taken of the actual water wheel which is down here, just to indicate the character of thing that we have to make drawings of, and I am not sure that we are all familiar with just what such drawings really constitute.

Over here is a general drawing of a dam, a spillway, with a crosssection shown here, and here is a photograph showing the downstream face of this power house, and this spillway over here. That is simply to indicate what these structures really are when you cut them in two and look at them like that.

Representative JENKINS. Colonel, there was a question that I asked you awhile ago about the Chickamauga Dam. Here is what I had in mind. I was a little bit at fault, but we will see if this is right. It is taken from the testimony in the Eighteen Power Co. case.

The Chickamauga Dam is completely flooded out with the top of its gates under 7 to 9 feet of water, by the maximum flood to be expected at Chattanooga. Colonel PARKER. That doesn't have reference to anything that has happened; that is a prediction that such would take place.

Representative JENKINS. But isn't it the fact that this indicates that the maximum flood to be expected in Chattanooga will be 7 or 9 feet over all of the dam structure?

Colonel PARKER. Now, may I explain what that really means again? I don't wish to go too far into Professor Woodward's territory, but I think that I can clear that up.

That might I don't know whether it is or not, but if such a flood reached Chickamauga Dam, such a statement might perhaps be true in part, but with adequate flood-control reservoirs upstream, which will constitute probably 80 or 90 percent of the flood-control storage provided, 80 or 90 percent of the amount of such flood-control storage provided would be retained in those reservoirs, and this maximum flood would never reach the Chickamauga, so that the water which reached Chickamauga would be readily regulated by it.

Representative JENKINS. If you got water in Norris like the last flood, you didn't know whether there was going to be a flood, then you wouldn't help Chattanooga.

Colonel PARKER. I don't recognize that allusion; that instance, as you describe it.

Representative JENKINS. Well, it is a fact that you had a flood that went over the top of Norris last year, didn't you?

Colonel PARKER. Well, my recollection is that we used Norris quite effectively during the last floods to aid in the flood control both at Chattanooga, and to a minor extent down the river.

Representative JENKINS. If when a flood does go over the top of a dam, at that time, that dam is clear out of commission as far as flood control or navigation is concerned, isn't it?

Colonel PARKER. I don't recall that the water passed over the top of Norris Dam.

Representative JENKINS. I am asking you of the case when the water goes over the dam, then its efficiency for navigation or flood control are both gone?

Colonel PARKER. That I think is too general a statement.

Representative JENKINS. Now, isn't it a fact-is a dam when the water is going over it, is it of any value for flood control?

Colonel PARKER. It depends upon how much water is going over it, and whether you are allowing for it.