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4. SITE OF PROPOSED DAM, GUNNISON CANYON, COLORADO.

B. TYPICAL VIEW IN GUNNISON CANYON, COLORADO.

done in 1902 above Beaver Camp, and with the points at the dam site from Camp Hill and Signal Hill. Distances were computed from the Olathe base line, this having been more accurately measured than the Bostwick Park base. The bearings were all taken with reference to Bostwick Park base, however, as all bearings of the survey were referred to this.

Owing to high water in the river it was impossible to do more than locate a flag at the foot of Boat-Landing trail, and other flags at the top of the cliffs visible from points near the proposed dam. All points are either hubs under tripods or chisel marks on rocks or else on short sights, short straight poles set at a central point between four hubs with tacks in their tops, set in a circle of about 1 foot radius.

The greatest error discovered in this system of triangulation was 11 seconds. On the connection with the dam site the greatest error was 17 seconds. These errors were adjusted, and it is not likely that there is any error greater than 10 seconds in any of the angles.

It should now be possible to run a tunnel tangent from station 19, the northwest end of Bostwick Park base, to whatever points may be selected at the valley end and at the double heading of the tunnel. This tangent, based upon the work of the year 1902, should hit the desired points within 1 or 2 feet, although the triangles of 1902 were not all closed, consequently minor adjustments could not be made.

It may also be possible to run a tangent line from the double heading to the gulch below the site of the proposed dam by extending the line back from each portal-from the west end across to the spur on the west side of the double-heading gulch, and from the east end by extending the line across to the top of the cliff on the north side of the river, and then running cast again with the points on the ledge over the intake. It will, however, be a difficult matter to run this tangent throughout, even if it is possible.

At the same time a traverse line along the 6,250-foot contour was run out by Mr. Charles, for the purpose of determining where the deepest indentations were to be found in the shale foothills on the Uncompahgre Valley side of Vernal Mesa. This line was run for several miles in each direction from the portal to the State tunnel. The contour line was first accurately run out by level and then mapped with the aid of a transit.

LAND SURVEYS.

In May and June W. P. Edwards, engineer, made a somewhat extended land survey upon Vernal Mesa and in Cedar Creek Valley for the purpose of determining whether or not the township and section lines had ever been run out, and for the further purpose of locating the tunnel lines and triangulation points with reference to Land Office surveys. He was furnished with a certified copy of the field notes of the original survey.

In the latter part of May he started at the marked corner of secs. 25 and 36, T. 49 N., R. 8 W., New Mexico principal meridian (in place), on the bank of Cedar Creek east of the station and ran north 7 miles to Gunnison River, finding neither corners nor any indications of lines ever having been run. Three corners on the east-west township line near Cedar Creek railroad station were, however, found and tied into the Boat-Landing triangulation. From this the section line can be plotted to the north.

It has been necessary to run certain other section lines in the Uncompahgre Valley. The Land Office surveys of this valley were fairly well made, so that in general it is not difficult to locate corners. Vernal Mesa and Bostwick Park were, however, clearly not surveyed at all, so far, at least, as the establishing of corners was concerned.

SURVEY OF ROADS.

In the early part of the season W. P. Edwards, engineer, was directed to make a survey for a road from the Uncompahgre Valley end of the proposed tunnel to the top of the Vernal Mesa, and then to the heads of the trails leading to the site of the proposed dam and to the double heading of the proposed tunnel. On June 9 Mr. Edwards reported on the stadia line survey for wagon roads from State tunnel to the dam site and double heading in effect as follows:

Starting on Vernal Mesa, at the head of the dam-site trail, the line ascends for 6,100 feet, with a grade of from 1 to 3 per cent, through good country to the summit saddle, one-half mile north of Jones's cabin; thence from station 0 to station 419, at the State tunnel, a distance of 44,000 feet, the road has a 5 per cent grade, excepting the one-half mile through Bostwick Park, which has an adverse up grade of 2 per cent. The total distance from the head of the dam-site trail to the State tunnel is 9 miles. It was planned that the roadbed should have a width of 12 feet, 3 feet of which it was intended should be occupied by a small drainage ditch, leaving 9 feet of actual roadway. Estimates were made on basis of cut slopes 1 to 1, fill 14 to 1.

A line for a branch road to the tunnel heading was also surveyed. This line leaves the main road line at the saddle one-half mile north of Jones's cabin, and runs for 2.2 miles on the north side of the divide to the head of the trail north of Dawsons Summit. Grades are as follows: From station 0 to station 31 the line is level. From station 31 to station 48 is a 2 per cent up grade, and from that point there is a 1 per cent up grade through easy country. This line is somewhat longer than the line surveyed in 1902, as the maximum grade was diminished from 7 and 8 per cent, and sometimes as high as 12 per cent, to 5 per cent for the new line. For about two-thirds of the distance, starting from the State tunnel, the two lines are through

practically the same kind of country, but for the remaining distance the location of the new line will be very much cheaper, in addition to being upon a better grade, than the line run in 1902. The road along the line selected will be an easy one to build.

There is already a fairly good road from Montrose to the State tunnel, so that little expense would be necessary on this part of the line.

RESERVOIR SITES.

During the month of August and part of September, W. P. Edwards, engineer, was directed to make a careful examination of the drainage basin of Gunnison River and its tributaries for the purpose of ascertaining whether any feasible reservoir sites could be found that might be used for the purpose of equalizing the flow of Gunnison River. In accordance with these instructions Mr. Edwards left Cimarron on August 1 and spent several weeks making the examination. On October 6 he submitted a report, the substance of which is as follows:

GUNNISON RIVER.

Gunnison River was examined on the south side from Gunnison to Iola, no reservoir sites being found. From Iola down on the north side the river was not examined.

TAYLOR- RIVER.

Investigations were made on Taylor River from Almont to near the headwaters above Dorchester post-office, in Taylor Park, T. 12 S., R. 83 W. Topographic surveys were made of two possible reservoir sites.

The lower site lies at the lower end of Taylor Park, in secs. 8, 17, 18, 19, and 20, T. 14 S., R. 82 W., sixth principal meridian. The discharge of the river at the dam site at the canyon entrance, on August 12, 1903, was 141 cubic feet per second. The indications are that solid granite rock may be found at the dam site by stripping 20 feet of soil and loose rock on the hillsides, and probably also below the river bed, under 30 feet of bowlders and gravel. The land which would be covered is pasture land.

The upper site is in secs. 26, 27, 28, 33, 34, and 35, T. 12 S., R. 83 W., sixth principal meridian, below Dorchester post-office. The material at the dam site is earth, gravel, and granite bowlders, with no sign of bed rock. The land which would be covered is pasture land. The discharge of the stream on August 14, 1903, was 37 cubic feet per second.

No reservoir sites were discovered on the following tributaries of Taylor River: Spring Creek, Lotty Creek, Willow Creek, Illinois Creek.

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