OF THE COMMISSIONERS OF PUBLIC WORKS.
217 is from 3 to 4 feet lower than at Charlemont, where the present river joins the Blackwater, Appendix (E.)
so that the fall in the new course will be that much greater, and it will be relieved from so much backwater :â€”2d-The benefit which will be afforded to the Blackwater itself between Annual Report of Charlemont and Vomer's Bridge, by relieving that portion of its channel from the very large ^ C* ?â€¢
9ttIe^Â» volume of water at present brought into it by the Tall and Callan.
This is the more important j?
District from the circumstance of that part of the Blackwater being shoal whereas at the intended nÂ»meer-debouche of the new Callan River it is amply wide and deep.
The new course above described has been in progress of excavation since July.
It runs principally through flow bog, which requires complete and gradual draining before removal; a system of longitudinal and transverse drains have accordingly been made throughout the length of ihe cut, which is 2^ miles, and these drains have been kept cleared and sunk, so that subsidence in the surface to the extent of 2 feet 6 inches has already taken place.
Upwards of half a mile of the new course at downstream end has also been finished, its bottom breadth being 21 feet, and its depth 6 feet below intended summer water in Lough Neagh.
The completion of this bog cut, which in one place is upwards of 30 feet in depth, will be tedious, but when accomplished the drainage of the lands along the Tall and Callan will be perfect, which I believe it never could have been under the originally intended system of embankments, which is always objectionable, if any direct mode of drainage can be devised.
The Rhone is a river of some importance, running into the Blackwater from the Tyrone side about 2-^ miles below Moy.
The lands along the Rhone banks have heretofore been always either flooded or saturated with water; but now they are altogether relieved from water, and 350 acres have thus been transformed from a swamp, or little better, into good land available for any purposes of agriculture.
The whole course of the Rhone was totally inadequate to discharge the water belonging to it, on account of its circuitious, character and its very insufficient dimensions both as to breadth and depth.
These defects have both been rectified by the formation of an entirely new channel, direct in its course and ample in capacity, one and a half miles in length, protected on its south side for the portion next the Blackwater by embankments sufficiently high to save the low lands there from flooding.
A further length of new channel for the Rhone is also in progress, and will be finished early in 1852.
In every ease the old course has been or is in progress of being filled up with the stuff excavated from the new one, so that it is presumed no land whatever will have to be paid for.
The Closet River runs into Lough Ncagh at Roughlan near Lurgan.
It is naturally sluggish, and the lands about it are particularly low.
The most defective part of it has been straightened and made deep, so that immediate relief was afforded to the lands which had suffered most from water.
Upper Tall River.
The upper reach of the Tall River was found to be very much choked up^with weeds, of many years growth and pending the further improvements to be made in this river; when its new outlet is established, these obstructions have been cleared out, and the water thereby has been visibly lowered, so as io afford much temporary benefit, at a small cost, to the wet lands adjoining it.
Since the excavation in the Blackwater was completed, we have had a hand-bucket dredger constantly at work removing the cross-dams, &c, and for the use of this machine we are indebted to Mr.
Dargan, who readily lent her to us for the purpose.
The following items of work have have been performed on the Blackwater and its tribuÂ¬ taries in 1851:â€”
-126,180 cubic yards.
Embankments made --5,945 lineal yards.
Back drains to ditto --735 perches.
Bog drains made ---3,900 perches.
In reference to the item of excavation, I have to explain, that it does not include the second shifting into the old course of the stuff excavated in straightening the Blackwaf er, although that work was done, and the quantity so shifted amounted to 48,000 cubic yards.
General summary of measured work done on the Lough Neagh district from the comÂ¬ mencement up to the close of the year 1851 :â€”
Rock excavation ---253,874 cubic yards.
Clay, gravel, &c.
ditto -934,584 â€ž
Total 1,188,458 â€ž The above quantity of excavation is altogether exclusive of desultory work done by the day, and is also exclusive of making and removing dams and filling old nver-courses.
Stone quarried and dressed --201,927 cubic feet.
Masonry built -13,677 cubic yards.