REPORT OF MR. R. DAVENPORT, ASSISTANT Engineer.

SAINT PAUL, MINN., June 30, 1884. SIR: I have the honor to submit the following report of a trip over that portion of the headwaters of the Mississippi River lying between Leech Lake, Winnibigoshish, Pokegama Falls, and Aitken, during the time that the log-drives were being turned into the main river from Pokegama Lake, Prairie River, Swan River, &c.

I first, as ordered, proceeded to Aitken, and established a gauge in the Mississippi River at that point.

At Aitken I found that the river above was full of logs, and that it would be impossible for a steamboat to get through to Grand Rapids for at least ten days. I therefore returned to Brainerd and started for Leech Lake Dam via the agency. I arrived at Leech Lake Dam at 8 p. m. on the 22d.

The dam was closed, the work-the completion of the apron-requiring that no water should be allowed to pass. Mr. Cullen reported that the work would be so far advanced as to enable him to open the gates on the 28th.

From Leech Lake I went to Winnibigoshish, arriving at the dam at 7 p. m. on the 24th. Mr. Wanzer, by order of Mr. Johnson, had allowed 900 cubic feet of water per second to pass the dam, from 2 p. m. on the 16th until 2 p. m. on the 24th, when a rainfall caused him, according to orders, to reduce the discharge to 750 cubic feet per second.

On the 26th Mr. Wanzer, by order from Mr. Johnson, opened the gates so as to allow a discharge of 1,500 cubic feet per second, but reported that with the head of water at the dam but little more than 1,200 cubic feet per second would pass.

The gates at Winnibigoshish had been closed up to the 16th to allow the rock required to complete the dam to be taken from the rapids below.

On the 25th I left Winnibigoshish for Pokegama Falls. The river between the dams, with a discharge of 750 cubic feet per second, was at a good navigable stage. All the lakes between Winnibigoshish and Pokegama are very low, the bar at the outlet of Ball Club Lake having only 6 inches of water over it. The 750 feet discharge from the dam fills the river well but does not overflow the banks or back up the water into the lakes or sloughs.

On my arrival at Pokegama Falls Dam on the 25th, I found that about 700 cubic feet of water per second was passing through the sluices. From the 14th to the 20th Mr. Johnson had kept the sluices closed in order that the water might be backed up into the outlet of Pokegama Lake, so that the "drive" from that lake, about 9,000,000 feet B. M., might be got out into the river and over the falls, as the logs were interfering with the work at the dam, and would continue to do so until they were moved below the falls.

I gave Mr. Johnson your views as to the advisability of allowing sufficient water to pass to insure the movement of logs between Grand Rapids and Aitken.

He informed me that he had ordered a discharge of 1,500 cubic feet per second from Winnibigoshish, and that he would order sufficient water to be let out from Leech Lake to make up 1,800 cubic feet per second. He further said that the discharge from the dams might be contingent on the condition of the work.

On the 27th, at 6 a. m., the logs from Pokegama being mostly in the river, a further opening of the gates was made at the falls and an estimated discharge of about 1,100 cubic feet per second was allowed to pass.

At 3 p. m. I left the falls with a canoe and started down river for Aitken; at this time the logs were being sluiced over the falls. From the falls to Grand Rapids there were many logs on the bars, but the main channel was open and logs running freely. From the appearance of the river and the manner in which the logs were moving I should judge that, in the present unimproved condition of this section of river, from 1,000 to 1,200 cubic feet per second would be required at this point for a fair driving stage. I passed the head of the Pokegama Drive about 15 miles below the rapids; there were no jams and there was plenty of water for either logs or steamboats.

Prairie River was discharging little or no water; I was informed that the lumbermen's dam was closed. Logs for the mills at Aitken were being held in Prairie River until the logs from Pokegama should pass that point, so they could be stopped at Aitken unmixed with the logs intended for the lower river.

I overtook and passed, at 6 a. m. on the 28th, the "rear" of the Prairie River Drive at Crooked Rapids; from this point to Sandy Lake the logs were thick but were running freely; there were no jams.

The stage of water at Sandy Lake was equivalent to a discharge of over 2,000 cubic feet per second, though the jams below might make the discharge less than the stage would call for under ordinary circumstances.

From Sandy Lake to Aitken the river was full of logs, with frequent jams. The wind for a number of days had blown hard up river; at any but flood stage this would cause jams at many places on this section of river.

I arrived at Aitken at 3 p. m. on the 28th, thirty hours after leaving Pokegama Falls. The stage of water at that place, elevation 1,191.143, would, under ordinary circumstances, without logs in the river, represent a discharge of about 3,000 cubic feet per second.

The water at Aitken was falling slowly; the additional discharge from the Pokegama Dam, commencing at 6 a. m. on the 27th, could not reach Aitken for several days.

With reference to the complaints made by the lumbermen as to detention to logdriving by the retention of the water at the dams, I am convinced, from personal observation, general information gained during the trip, and the records now on file in this office, that the detention, if any, has been largely overestimated.

It was absolutely necessary to close the dams for a short time; at Leech Lake to finish the apron, after the 3d of June; up to that time from 100 to 200 cubic feet per second had been allowed to pass; at Winnibigoshish, to allow the stone necessary for facing the dam to be taken from the rapids 3 miles below little Winnibigoshish. The dam at Pokegama Falls was closed only to back the water up into the lakes, at the outlet of Pokegama, so that the logs from that lake, as before mentioned, might be got out into the river and out of the way.

The failure to get the Pokegama logs out in time was principally owing to the construction, by the loggers, of an imperfect cutaway dam near the main lake.

The Prairie River logs reached the main river on the 16th or 17th, after being held by wind twenty days in Prairie Lake.

The Swan River logs reached the river on the 21st or 22d.

All the drives were from two to three weeks late in getting their " main river, and consequently were too late for the first high water.

rear" into the

Owing to the unusually dry fall of last year, the marshes and lakes were very low, and consequently the second, or June flood, did not amount to much.

The jam in the reservoirs, excepting the short time that it was necessary to close the dams on account of the work, was principally from the first spring flood, at which time there was plenty of water in the river below.

I am of the opinion that but for the aid of the water from the reservoirs this season the three "drives" before mentioned would have been "hung-up," or at least have had great difficulty in getting out at all.

Very respectfully, your obedient servant,

Maj. CHAS. J. ALLEN.

Y II.

SURVEYS FOR RESERVOIRS AT THE SOURCES OF THE MISSISSIPPI, SAINT CROIX, CHIPPEWA, AND WISCONSIN RIVERS.

If the reservoir work now begun in Minnesota at the headwaters of the Mississippi River is to extend to the Saint Croix, Chippewa, and Wisconsin rivers, it will be necessary, in order to meet questions constantly arising, as well as to be enabled to make closer estimates of cost of dams, &c., to continue hydrological observations, to continue borings at proposed dam sites, to recontour some of the sites, and to work up the maps, drawings, and estimates.

The estimated cost of such examinations for one year is $50,000. There having been no appropriation for such work during the past fiscal year nothing was done under this head.

Money statement.

Amount that can be profitably expended in fiscal year ending June 30, 1886. $50,000 00

Y 12.

PRELIMINARY EXAMINATION OF THE SOURCE OF THE MINNESOTA RIVER, NEAR THE FOOT OF BIG STONE LAKE, WITH A VIEW TO ITS BEING ADDED TO THE RESERVOIR SYSTEM OF THE MISSISSIPPI RIVER AND ITS TRIBUTARIES.

UNITED STATES ENGINEEr Office,

Saint Paul, Minn., November 24, 1882. GENERAL: I have the honor to render the following preliminary report upon an examination of the source of the Minnesota River, near the foot of Big Stone Lake, ordered by river and harbor act of Congress, passed August 2, 1882. The words of the act are: "The source of the Minnesota River, near the foot of Big Stone Lake, with a view of its being added to the reservoir system of the Mississippi River and its tributaries."

The examination of the ground was intrusted to Assistant R. Dav enport. Extracts from his report are submitted herewith.

The maps in this office of Big Stone Lake and vicinity, made in 1872 by Col. J. N. Macomb, Corps of Engineers, were of great value in connection with the examination.

Big Stone Lake drains an area of about 1,636 square miles, including in this area the watershed of Whetstone Creek, the principal tributary near the foot of the lake. The average annual precipitation-rain and melted snow-upon this area is 21.2 inches. Assuming that but onefourth of this quantity actually finds its way into the lake, the rest being lost by evaporation, infiltration, absorption by vegetation, &c., the annual supply to the lake would not be less than 20,000,000,000 cubic feet of water.

The lake is about 25 miles in length, with width varying from a half mile to 1 mile; an average depth at low water of 10 feet.

A dam at the lower end of the lake of 10-foot lift above ordinary low water would produce a reservoir of about 22 square miles area and 5,742,950,400 cubic feet capacity, furnishing for one hundred days about 665 cubic fet per second, a quantity which, if impounded to add to the low-water flow of the stream, would in the upper part of the Minnesota River be of value were there any commerce of consequence to be benefited.

The supply, it will be seen, is about 14,000,000,000 cubic feet more than the capacity of the reservoir. It would probably be advisable, were a reservoir constructed here, to divert the discharge of Whetstone Creek to its old channel, thus bringing it below the dam site, in order to reduce the level of floods at the time of a full reservoir. This diversion of the Whetstone would reduce the annual supply to about 9,200,000 000 cubic feet, still leaving a surplus supply of nearly 3,500,000,000 cubic feet of water.

A 10-foot lift, which is probably the lowest that should be given, would flow out, according to Assistant Davenport, eight hundred to one thousand acres of meadow land belonging to private parties, damaging the latter to the extent of about $60,000.

Nothing like an exact estimate of the cost of a dam or of damage to private property can be arrived at without a full survey of the locality, the cost of which survey I should place at $2,500.

If the reservoir system should ever be carried to the full extent of which it is capable, Big Stone Lake and other holding grounds proba

bly would be included. At present, however, the commerce of the Minnesota River would not appear to warrant the expense of turning Big Stone Lake into a reservoir.

There are no commercial statistics to report.
Very respectfully, your obedient servant,

Brig. Gen. H. G. WRIGHT,

Chief of Engineers, U. S. A.

CHAS. J. ALLEN,

Captain of Engineers.

REPORT OF MR. R. DAVENPORT, ASSISTANT ENGINEER.

ENGINEER'S OFFICE, UNITED STATES ARMY,

Saint Paul, Minn., November 20, 1882.

SIR: As instructed in yours of November 3, 1882, I have the honor to submit the following report of an examination of Big Stone Lake, made with a view to its being added to the reservoir system of the Mississippi River and its tributaries.

Big Stone Lake, on the line between Minnesota and Dakota, is about 25 miles long, from one-half mile to one mile wide, and has an average depth at low water of about 10 feet. The bottom of the lake is generally sandy, with frequent beds of bowlders near the shore. The banks are composed of sand and bowlders and are from 6 to 15 feet high, except at the extreme ends of the lake, where there are extensive marshes and meadows. Back of the banks, and parallel with them, are narrow strips of bottom land, generally not more than 400 feet wide, that extend to the foot of the bluffs that rise from 150 to 160 feet to the level of the surrounding prairies.

There are three villages on the lake-at the south end, Ortonville, in Minnesota, and Big Stone in Dakota; they have a joint population of about 1,300. The Hastings and Dakota Railroad touches the lake at this point. The village of Brown's Valley, population about 400, is at the north end, and is the present terminus of the Little Falls and Dakota Railroad.

The valley at the point where the proposed dam would probably be built is a shallow marsh or bog, of an average width of about 4,000 feet. Underlying the marsh is a deposit of sand and bowlders. A thick bed of clay is found at an average depth of about 15 feet below the surface of the marsh. Clay is also found in the adjoining bluffs at from 5 to 15 feet below the surface. Stone for the construction of a dam would be available and cheap, as there are large outcroppings of granite in the immediate vicinity.

The Minnesota River, at this point a very small creek at low water, runs through the lake and is the only constant contributor to its volume, though a number of ravines or conlés, dry during the summer, extend back from the lake in various directions, and drain a large area of country during the flood season (April to June).

The Whetstone, a creek of about the same size as the Minnesota, originally joined the Minnesota in Big Stone Valley, about 2 miles below the lake, but the water is deflected by a dam constructed for milling purposes, and the discharge is now practically into the lake.

The discharge of both the Whetstone and Minnesota at low water is not more than 50 cubic feet per second, but during the spring floods the discharge of both streams is very large. The Whetstone alone has frequently filled the entire valley below, the backwater for a time forcing a strong current up the lake. Owing to the location of its outlet the discharge from the Whetstone can be included in the supply for the proposed reservoir, or it can be left out without any particular detriment.

The rise in the lake during the spring floods is from 5 to 10 feet, and it usually remains at the flood stage from April 15 to June 1; after that time the water gradually recedes, generally reaching its normal level by the 1st of July.

As a holding ground, Big Stone Lake has a low-water area of 18 square miles; at 7 feet above low water, an area of 20 square miles; and at 10 feet, it is estimated that the area would be increased to 22 square miles. Any considerable rise above 10 feet would increase the area very rapidly, and so large a tract of valuable land, including probably a part of the village of Brown's Valley, would be liable to damage, that, in this report, 10 feet has been considered the maximum height that it would be desirabe to raise the water.

It is estimated that at the north end of the lake a 7-foot flowage would destroy nearly 500 acres of meadow lands, valued at $50 per acre; a 10-foot flowage would destroy or damage from eight hundred to one thousand acres, valued at $50 per acre. At the south end and on the east and west banks the damage would be light. The

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