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In recapitulating the several routes by which the canal may be directed through them, wo will observe that they all extend from the mouth of Savage River, either by the valley of that stream or Crabtree Creek, to the base-mark on the bridge of Deep Creek, and that the descent or fail of the canal by all these routes is 1,4:32 feet,

1st. The first ascends by Savage River, Monroe Run, Meadow Mountain Run, and Deep Creek. Its total length, from the mouth of Savage River to the base-mark, is twenty-one miles 325 yards. The length of the tunnel which it requires through the ridge is five miles 8334 yards, and the height of the ridge above its bed, 213 feet.

2d. The second ascends by Savage River, Crabtree Creek, Middle Fork, Meadow Mountain Run, and Deep Creek. Its total length is nineteen miles 915 yards. The length of the tunnel which it requires through the ridge is three miles 1,333} yards, and the height of the ridge above its bed is 210 feet.

3d. The third ascends by Savage River, Crabtree Creek, Middle Fork, the western branch of the same fork, North Glade Run, and Deep Creek. Its total length is twenty miles 1,128 yards; the length of the tunnel which it requires tbrough the ridge, three miles 125 yards, and the height of the ridge above its bed, 144 feet.

4th. The fourth ascends by Savage River, Crabtree Creek, Middle Fork, the eastern branch of the same, North Glade Run, and Deep Creek. Its total length is twenty miles 1,306 yards ; tbe length of the tunnel which it requires through the ridge, three miles 83 yards; the height of the ridge above its bed, 184 feet.

5th. The fifth ascends by Savage River, Crabtree Creek, Rocky Camp Ruu, North Glade Run, and Deep Creek. Its total length is nineteen miles 630 yards; the length of the tunnel wbich it requires through the ridge, four miles, and the height of the ridge above its bed, 222 feet.

61h. The sixth ascends by Savage River, Crabtree Creek, Savage Lick Run, North Fork, aud Deep Creek. Its total length is twenty-one miles 435 yards; the length of the tunnel which it requires through the ridge, two miles 1,083 yards, and the height of the ridge above its bed, 148 feet.

7th. The seventh ascends by Savage River, Crabtree Creek, Hipcb's Arm, Glade Road Run, North Fork, and Deep Creek. Its total length is twenty-one miles 1,158 yards; the length of the tunnel which it requires through the ridge, one mile 1,166 yards, and the height of the ridge above its bed, 205 feet.

8th. The eighth ascends by Savage River, Crabtree Creek, a ravine of Crabby's Arm, Dry Arm, North Fork, and Deep Creek. Its total length is twenty-one miles 1,368 yards; the length of the tunnel which it requires through the ridge, one mile 916 yards; and the height of the ridge above its bed, 271 feet.

9th. The ninth ascends by Savage River, Crabtree Creek, a ravine of Crabby's Arm, Dewickmau's Arm, North Fork, and Deep Creek. Its total length is twenty-one miles 718 yards; the length of the tunnel which it requires through the ridge, one mile 6834 yards; and the height of the ridge above its bed, 227 feet.

From the base-mark the localities of the ground leave us a choice between three routes to the mouth of Bear Creek.

The first runs by Deep Creek, Buffalo Marsh Run, Rocklick Run, a tributary stream to the western branch of Bear Creek, that western branch to its month in Bear Creek, and Bear Creek itself to the Youghiogheny. This route crosses, by a tunnel, the ridge which divides the heads of the western and eastern branches of Bear Creek. This tunnel beginning at McHenry's, and with an open cut of the depth of 35 feet at its southern extremity, near McHenry's, and at its northern extremity, would extend about two miles in length, and the greatest height of the ridge above its bed, supposed on a level with the base-mark, would be about 170 feet. The whole ground along this route, except where it passes throngh the gap of Winding Ridge, is of a soft and good quality; and its rhole length, from the base-mark to the mouth of Bear Creek, would be only twelve miles.

A second route might turn round the west of Marsh Mountain, and wind about Panther's Point. It would then turn snccessively round the heads of the ravines of Hoy's Run, Steep Run, Sang Run, Gap Run, and descend along Friend Run, a tributary of the western branch of Bear Creek. This route is very circuitous, and in winding round Pantber's Point runs through a rocky and difficult ground. It could only be shortenedl by running an aqueduct 250 feet high, and above a quarter of a mile long, through the western branch of Hoy's Run, or a tunnel half a mile in length from that western branch to the head of Steep Run. The height of the ridge above the bottom of that tunnel would be about 250 feet. A level was also run over a bend of ground at Hoy's Pire Bottom to endeavor to shorten it and avoid the winding round of Panther's Point, but to run the canal over this line would require a deep cut of 1,431 yards in length, and of the depth of 99.06 feet, at the highest point of the ridge. The total length of this route would be twenty-four miles.

The third route, descending the valley of Deep Creek from the base-mark, might follow the eastern shore of the Youghiogheny to the mouth of Bear Creek, crossing successively on aqueducts Hoy's Rum, Steep Run, Sang Run, Gap Run, Bear Creek, and the smaller tributary streams of that river. The ground along this route is rocky

and difficult for one mile and three-quarters from Deep Creek to Hoy's Run; then light and easy for four miles to Gap Run; then rocky for the space of six miles, following the western bank of Winding Ridge ; tben for two and a quarter miles light and easy to the mouth of Bear Creek. The total length of this route would be twenty miles.

We bave not mentioned a fourth route, which, from the base-mark, running by a tunnel through Negro Mountain, might unite Deep Creek with the eastern branch of Bear Creek, because it would require a tunnel of eight miles in length, and that the height of the ridge above its bed would be from 400 to 500 feet in the most elevated portion. The length of this route would also pass twenty miles.

Such are all the routes which lead from the valleys of Savage River and Crabtreee Creek, in passing by that of Deep Creek to the mouth of Bear Creek, in the Youghio. gheny. We must now examine those wbich, departing from the head of Crabtree Creek, reach the same point in passing by the valleys of the Little and Great Youghiogheny.

For this purpose the canal should follow the valley of Savage River from the mouth of that stream, and ascend along Crabtree Creek till it reaches two miles above Swan's Mill, where opens the eastern extremity of the tunnel of Crabby's Arm, inentioned on page 10 as the shortest of those by which Savage River can be connected with the Yougbiogheny. Passing through that tunnel it would descend the valleys of the Little aud Great Youghiogheny, winding along their eastern sides. When it reaches the mouth of Deep Creek, it may follow one of these three directions:

1st. Ascend Deep Creek and Buffalo Marsh Run, following the first of the three rontes which we have just indicated for passing from the base-mark to the mouth of Bear Creek. This route, as we have seen, presents a tunnel two miles in length. The total distance over which it runs is as follows:

Miles. Yards. From the month of Savage River to the east extremity of the tunnel of Crabby's Arm

15 86 From thence to the mouth of Deep Creek

22 426 From thence to the mouth of Buffalo Marsh Run.

6 From thence to the month of Bear Creek..

11 440

Total distance from the mouth of Savage River to that of Bear Creek.. 54 952 This route would present two tunnels, one three miles 1,538 yards in length at Crabby's Arm, and the otber two miles in length between Buffalo Marsh Run and Rocklick Run; total, nearly six miles of tunneling.

2d. The canal might cross Deep Creek and follow the second route indicated for passjpg from the base-mark to Bear Creek, by winding round Panther's Point, and the heads of the ravines of Hoy's Run, Steep Run, Sang Run, Gap Run, and Friend Run to the westeru branch of Bear Creek. Its total length would be:

Miles. Yards. From the mouth of Savage River to that of Deep Creek, as above.. 37 512 From thence to Bear Creek

17 660 Total length

54 1, 172 This route presents only one tunnel, of the length of three miles 1,538 yards, or nearly four iniles, at Crabby's Arm. It may also be shortened, as mentioned above, by an aqueduct one fourth of a mile in length and 250 feet high, or a tunnel one-half mile in length, with 250 feet of height of ridge above its bed.

3d. The canal might fall on this third ronte indicated above, after crossing Deep Creek, by keeping along the eastern side of the valley of the Yonghiogheny, and crossing its tributaries on aqneducts. Its total length would be as follows:

Miles. Yards. From the mouth of Savage River to that of Deep Creek, as above..

37 512 From thence to Bear Creek

13 660

Total length ....

50 1, 172 This ronte would require, like the preceding one, one tunnel, of three miles 1,538 yards, or nearly four miles in length.

From the comparison of these three routes it is evident that the second is preferable to the first. Their length is nearly the same, but the first requires six miles of tunneling and two tunnels, while the second requires only one tunnel, of something less than four miles in length. The third is shorter again, by four miles, than the second, and passes by the same tunnel. Aqueducts must be constructed on this route to cross Hoy's Rún, Steep Run, Sang Rup, Gap Run, and Bear Creek, but by the successive dropping of its levels they will require but a small elevation, and the waters of these runs and of the Great Youghiogheny may be raised and used to feed the canal, an advan

tage which the other routes do not offer. It should also be observed that these runs are not above 200 or 300 feet wide at their mouths in the Youghiogheny. The third route is therefore preferable to the two others, on the hypothesis of uniting the months of Savage River and Bear Creek through the valleys of the Little and Great Youghiogheny.

We will now compare this route, which we will call the Youghiogheny route, with those which lead from Crabtree Creek to Deep Creek.

Nine routes, which all unite at the base-mark, have, as we have stated before, been examined for this purpose. Their length varies only from nineteen to twenty-two miles, but their tunnels present a much greater difference. The longest extends five miles 8335 yards, or about five and a half miles; and the shortest, one mile 6835 yards, or about one and one-third miles in length. The last should certainly be preferred. Its whole levgth is twenty-one miles 718 yards; and the greatest height of the ridge above its tunnel is 227 feet. We shall call it Dewickman's Arin route.

We have also observed that there are three routes from the base-mark to the mouth of Bear Creek. Tbe first runs twelve miles, by Buffalo Marsh Run, and Rock Lick Run. It is the shortest, but requires two miles of tunneling. Were it not for this obstacle it offers a favorable ground for digging the canal. The second, winding round Panther's Point and the heads of Hoy's Run, Steep Run, Sang Run, Gap Run, &c., is twenty-four miles long, and is objectionable, not only for its length, but from the difficulties which it presents in turning Panther's Point. The third, by the valleys of Deep Creek and of the eastern bank of the Youghiogheny, is twenty miles long. It is shorter by four miles than the second, and requires no tunneling. In tbis respect it is superior to the first; for two miles of tunnel costs more than eight miles of canal, which is the difference of their length. The passage of an active trade will also meet with more delay on a tunnel of two miles, unless its dimensions are very large, than on four or six miles of canal. This route possessing, besides, over the two others, the advantage of feeding the canal below the mouth of Deep Creek, by raising the waters of the Great Youghiogheny and its tributaries, is preferable to them in all respects.

If we add the twenty miles of this route to the twenty-one miles 718 yards of Dewickman's Arm route, we shall have for the whole length of the canal, passing along Cabtree Creek, Deep Creek, and the valley of the Youghiogheny, forty-one miles 718 yards, with one tunnel one and a third miles in length, and the height of the ridge above it 227 feet. We shall call this route Deep Creek route, in opposition to the Youghiogheny route.

To decide between these two routes, which alone can enter in competition, we must compare their length, and the time, expense, difficulties, and trouble of their construction, viewed in a general manner.

The length of the Deep Creek route is forty-one miles 718 yards; that of the Youghiogheny route fifty miles 1,172 yards. The former is, therefore, shorter by nine miles than the other.

The tunnel from Dewickman's Arm on the Deep Creek route is one mile 6834 yards in length, and the height of the ridge above its bed is 227 feet. The tunnel between Crabby's Arm and the Little Youghiogheny, on the Youghiogheny route, is three miles 1,538 yards in length, and the height of the ridge above its bed is 464 feet. The former requires two miles 855ğ yards less of tunneling, and the height of the ridge above the bed of its tunnel is 237 feet less. With respect to the expense of tunneling, the route by Deep Creek is, therefore, preferable to the other.

As to the deep cuts at each extremity of these tunnels, the deep cut at the western extremity of the tunnel, toward the Little Youghiogheny, is two miles 930 yards in length. The deep cnt at its eastern extremity, toward Crabby's Arm, is 900 yards. The whole deep cutting on the Yougbiogheny route is thus three miles 70 yards.

The deep cut at the western extremity of the other tunnel, toward Deep Creek, extends five miles 1,096 yards. The deep cut at its eastern extremity, toward Dewickman's Aim, 572 yards. Total, five miles 1,668 yards.

The Youghiogheny route will therefore require two miles 1,598 yards less of deep cutting than the other at the extremities of its tunnels. But this advantage is not to be weighed with the expense of two miles 8.55 yards more of tunneling.

In comparing the nature of the soil on each of these routes and the obstacles which it may present, it must be remembered that their eastern portion, from Savage River to Crabby's Arm, and their western portion, from the mouth of Deep Creek to that of Bear Creek, are the same. In the intermediate space the ground is equally favorable and easy to work on both routes.

On the whole comparison of their respective lengths, of the time necessary to pass through the one or the other of the obstacles which they meet, and the expense and probable tiouble of their construction, we believe the Deep Creek route preferable to the route by the Youghiogheny.

Our next task must be to compare the supplies of water which the canal may receive on either of these routes, and this will lead us to a detailed investigation of the re

sources which are offered by the water-courses of the country to feed the iniddle section and summit-level of the proposed canal.

Savage River and its tributary, Crabtree Creek, may feed the eastern branch of the middle section, and the great Yonghiogheny its western branch. The summit-level must draw its resources from Deep Creek and the heads of the Little and Great Youghiogheny.

These streams were all gauged in 1824 at their lowest stage. We will give, in a general mauner, the result of these operations, the minimum, in cubic feet of water, that tlows through each stream in a second.

EASTERN BRANCH OF THE MIDDLE SECTION.

Cubic ft. Savage River gave on the 25th September below the mouth of Crabtree Creek, in a second...

17.73 Savage River gave on the 23th September at its mouth, (it had, however, rained this day)...

46. 09 Savage River gave on the 20 September below Monroe Run.

28.62 Monroe Run gave on the 28th September at its mouth..

0.83 Monroe Run gave on the 16th September at its mouth.

2.23 Crabtree Creek gave on the 14th September at Swan's mill.

0,97 Middle Fork gave on the 15th September at its mouth in Crabtree Creek. 0.81 Rock Camp Run gave on the 20 September at its month in Crabtree Creek... 0.12 Savage Lick River gave on the 14th September at its month in Crabtree Creek 0.33 Crabby's Arm gave on the 17th Angnst at its mouth in Crabtree Creek..

0.21 Wilson's Fork gave on the 17th August at its inouth in Crabtree Creek.

0.35 If we consider that the water consumed in the lockage of this branch is supplied from the summit-level, these streams, turned into reservoirs by dams throwu across the tributaries of Crabtree Creek and Savage River, above the mouth of that creek will serve to supply its losses from filtrations and evaporation. Between the month of Crabtree Creek and the Potomac, on a distance of five and one-half miles, Savage River, which gives 17.73 cubie feet in a second at its lowest stage, will serve for this purpose. In the remaining nine and one-half miles from the tunnel to the mouth of Crabtree Creek the Middle Fork gives 0.81 cubic foot; Rock Camp Ruin, 0.12 cubic foot; Savage Lick Run, 0.33 cubic foot; anı Crabtree Creek itself, 0.97 cubic foot, at Swan's mill, at their lowest stages; total, 2.25 cubic feet. Reservoirs may besides bo formed in the Middle Fork, Savage Lick Run, and Rock Camp Run. Filtrations may also be prevented, in a great degree, by a careful construction of the bed of the canal; and from observations taken in the summer of 1824 the loss from evaporation did not exceed the quantity received by summer rains. It may also be observed that any deficit will prove to be amply supplied by the waters of the summit-level.

From the mouth of Savage River the canal may be supplied from the North Branch of the Potomac, wbich, on the 18th September, gave 106 cubic feet in a second; and a great reservoir may be formed in it above the mouth of Savage River. From this point, therefore, it needs no longer the waters of Savage River nor of its tributaries. And if we except the waters required for its lockage, which will be supplied from the summit-level, this branch of the middle section may be fed in a great degree by the streams which fall into it.

WESTERN BRANCH OF THE MIDDLE SECTION,

This portion of the canal begins in Deep Creek, five miles below the base-mark, and erds at the mouth of Bear Creek. Its length is fourteen and three-fourths of a mile, and, like the former branch, it will receive from the summit-level the waters requireil for its lockage.

Hoy's Run, Steep Run, Sang Run, and Gap Run may be employed to feed it and repair its losses; but these streams have not been gauged. They may, nevertheless, offer some resources for reservoirs, Bear Creek may also form a great reservoir, by damming its valley and feeding the western section of the canal, but cannot feed the western branch of the middle section, from the difference of their levels.

Deep Creek is the only stream of any importance whose waters may supply the losses of this branch from filtrations and evaporation. We should, therefore, examine aceirately the means which it offers for this purpose. Its usnal depth under the bridge is 3 feet; but in its freshets it rises to 12 feet. High freshets generally occur in this stream twice or thrice a year, and last from three to four days; when the rains last so long, it gives, during that time, from 400 to 500 cubic feet a second. During the most unfavorable season it still has fresbets, less considerable, but which, nevertheless, give it a mean discharge about 100 cubic feet in a second each time; these occur from six to eight times a year. In the dryest months it gives, under the bridge, from 10 to 5}

cubic feet a second ; on the 27th August, 1824, it gave 5.12 cubic feet, which was the lowest quantity we ever found.

Supposing a dam erected across Deep Creek at the head of its rapids, and five miles below the base-mark, its basis would be 194 feet below that mark; its length would be 1367 yards, and to raise its waters 4 feet above the base-mark its height should be 231 feet. This dam would raise the waters of Deep Creek so as to overflow an area of 948,924 square yards, from accurate surveys. The prism of this reservoir, comprised between its surface and a horizontal plane, run 3 feet below the base-park, would be 7 feet high, and contain in capacity 2,214,156 cubic yards. In less than three months of the rainy season, if we allow only 9 cubic feet, or one-third of a cubic yard a second to the average supply of Deep Creek, this reservoir would be filled. It would be filled in less than five months in summer if the stream yielded at the rate of 5 cubic feet. Thus, every year, and for nine months of navigation, from the middle of March to the middle of December, we may depend on a supply equal to twice the capacity of this basin, or 4,428,312 cubic yards. Töis is equivalent to 492,034 cubic yards a month, and supposes only a mean supply of 5} cubic feet a second. This is the minimum of what Deep Creek can supply to repair the losses of the western branch of the middle section from filtrations and evaporation. To ascertain its sufficiency, we must examine next what those losses may amount to.

The length of this section is fourteen and three-quarter miles. Supposing it 5 feet deep, 28 feet broad at the bottom, and 44 feet at the surface of the water, the prism of its capacity will have a base of 20 cubic yards, on a length of fourteen and threequarter miles, equal to a cube of 519,200 cubic yards. This will be filled in the first days of March without deranging the economy of water which we have just analyzed. We have already observed that Deep Creek may supply every month a cube nearly corresponding to this, or 492,034 cubic yards, at the minimum rate, and lowest stage of its flow; we must now examine whether this supply will suffice every month to the filtrations and evaporation of fourteen and three-quarter miles of canal.

Without entering into minute calculations which properly belong to the report accompanying the final project of the canal, we will state generally the most positive results which experience has given as to the joint amount of filtrations and evaporation. Having ascertained that no experiments of this nature have been tried on the Erie Canal, where the supply of water was found evidently more than sufficient, we were obliged to consult the results of those canals constructed in Europe, under a climate which, in the summer, comes Dearest to our own. We have selected for this purpose the canal of Narbonne, in the south of France. Narbonne and Baltimore, compared as to climate and rain, are as follows:

Narbonne, latitude north 430' 11', (from observations made during twenty years.) Mean greatest heat, 95° ; mean temperature, 60°; mean greatest cold, 24° ; mean quantity of rain, 29.30 inches.

Baltimore, latitude north 39° 17', (from observations made 1817–1822, by Mr. Lewis Brantz, of Maryland.) Mean greatest heat, 910.56 ; mean temperature, 520.23 ; mean greatest cold, 00.12; mean quantity of rain, 38.60 inches.

Of all such works, the capal of Narbonne has given most trouble to its engineers, from its excessive filtrations and loss of water in the gravelly soil through which it is

It is a branch from the canal of Languedoc to the city of Narbonne, three miles in length. As soon as it was opened, in 1788, it lost the value or contents of its prism in a few days and overflowed the surrounding country; in 1789 it still lost the value of its prism in six days; and in 1800 it lost it in eighteen days, or the value of its prism and two-thirds every month-sixteen and two-thirds times its contents in ten months' navigation. This evaluation is the result of careful and accurate observations; and, considering the climate and soil through which this canal runs, it may fairly be taken as a specimen of the maximum loss which a canal can suffer through filtrations and evaporation.

The ground through which runs the western branch of our middle section is of a quality far superior to the country through which runs the Narbonne Canal. It is, for six and one-fourth miles, of an excellent quality; the remaining eight and one-half miles run through a rugged and rocky soil, but clay is everywhere at hand to puddle the bed of the canal, if necessary. Supposing, therefore, that its losses from filtrations and evaporation equaled in one month the cube of its prism, or 519,200 cubic yards, this would certainly be their maximum, while the evaluation of 492,034 cubic yards of water, which we have given as the supply from the reservoir of Deep Creek in one month, is its minimum. For it must be remembered that we valued this supply from the lowest result, obtained at the lowest stage of Deep Creek, when it gave only five and one-eighth cubic feet in a second.

We have allowed no loss for the evaporation from the surface of the reservoir, as it will be compensated by the frequent rains which fall on the summit of the Alleghany. From observations made in July, August, September, aud October, 1824, in the valley of Deep Creek, we have ascertained that there fell, from 19th to 30th July, four days of rain, 4.36 inches, 55° mean temperature; from 1st to 31st August, eight days of rain, 2.31

run.

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