344 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[October, 



The I'pper Lougli may be termed a scries or chain of I^ikes, branching ami 

 .ramifying its courte along tlic vallies of the country, forming numerous inlets, 

 whicli arc sufficiently rleep at the lov.est water to navigate vessels of con- 

 siderable burthen, and which att'ord a ready means of transit for merchandize, 

 and the produce of tlie country, in eveiy direction, particularly to Belturbet, 

 Enniskillen, and Belleek, which latter place is situated on the Lower Lake, 

 and is only tliree miles distant from the seaport town of Ballyshannon. 



Near Wattle Bridge, on the eastern side of the Lough, the Ulster Canal 

 enters, which I expect will be opened in the course of a few months. This 

 canal will form one of the grand outlets for the produce of this finely culti- 

 vated country to Belfast, -Newry, ic, it being at present shut out completely 

 from competition in these markets, on accouut of the want of a ready and 

 cheap conveyance by water ; and when such great facilities for intercourse 

 and trade present themselves, and requiring comparatively so small a sum for 

 accomplishing such a desirable object, it appears somewhat extraordinary 

 that the improvement of the navigation of this fine sheet of water should 

 have been so long deferred. 



Tlie several shoals, eel weirs, and other impediments to the navigation, 

 besides causing the before-mentioned disadvantages, also act as dams across 

 the channel, and retard the natural and regular flow of the water, which is 

 backed up to an incalculable extent, and thrown over the low lands along 

 the ditterent vallies bordering on the lakes, sulnnerging and inundating for 

 several months of the year, from 20,000 to 30,000 acres of the finest land in 

 the country, which, if the water could be taken off, might be brought under 

 the most perfect state of cultivation. 



I found, from observations and levels taken on the spot, that the difference 

 of level between the winter floods in January last, and the summer water in 

 May, at the undermentioned points, wa - as follows, viz. 



Belturbet and Wattle Bridge 9 ft. inches. 



Enniskillen 7 10 



Belleek 4 



and the surface of the water, between these points, forms nearly an inclined 

 plane. The least or smallest rise is at Belleek, which is owing to the Lower 

 Lake being of so much greater extent than the Upper one, and acting as a 

 compensation reservoir, and allowing the water to escape more uniformly. 



Having given a general description of the lake, I will now enter more into 

 detail, and describe the impediments which exist in the narrow parts of the 

 river, their effects, and what alterations are necessary to improve the navi- 

 gation and drainage of the country from Belleek to Belturbet, and having 

 been supplied, as 1 before mentioned, with the very accurate charts i)ublished 

 by order of the .\dmiralty, w hicli point out distinctly the deep and shallow 

 parts of the lake ; it became, therefore, unnecessary for me to take the 

 soundings of the whole extent of the lakes, my principal duty was to investi- 

 gate tlie shoals and impediments existing at the following places and points, 

 viz. 



1st. From Belleek to Roscor. 



2nd. Portora. 



3rd. The two channels and bridges at Enniskillen. 



4th. Dane's Eel Weirs. 



5th. Carry Bridge. 



6th. Black Rock, and some small ridges of gravel, on the south west 

 passage near Crom Castle. 



7th. Blockson Shoal, which is within two miles of Belturbet, and com- 

 posed*of solid limestone rock. 



Accurate soundings were taken at the above places, and plans, longitudinal 

 and transverse sections have been jirepared wiiich I now forward, showing 

 the depth of water, with the line of proposed deepening for improving the 

 navigation and drainage. 



The soundings and other observations were taken at a very favourable 

 timfe, viz., the latter end of hist .\pril and the beginning of May, when the 

 season was remarkably fine and dry ; so much so that the water was within 

 six inches of the lowest point ever reracndjered by the oldest inhabitant re- 

 siding on the Lake — the floods during the previous winter season being the 

 highest ever recollected. 



The above being the case, I was afforded a good opportunity of judging of 

 the effects likely to be produced by " reducing the waters to a uniform 

 level." 



The datum or surface of water shown on the sections, is supposed to be 

 nine feet eight inches under the lower edge of the string-course at the 

 springing of the abutment arch, S. W. angle of the West bridge at Ennis- 

 killen. 



At this level, the water being very tranquil, and with scarcely any percep- 

 tible current, I found, by taking accurate levels of the shoals at Portora. En- 

 niskillen, and Dane's Eel Weirs, that the difference of surface between the 

 Upper and Lower Lakes, at their extreme points, only amounted to 2| ins. — 

 I was gratified upon determining this fact to find there was no necessity for 

 erecting a lock, as I had been led to suppose there was a fall of from two 

 feet to three feet between the two lakes. This not being the case, it will 

 simplify the works required to be done, both in the execution and the ex- 

 penditure. 



The bridge of Belleek is of old construction, and appears in a very dilapi- 

 dated state. It is built with rubble masonry, and composed of four arches 

 of the following dimensions, viz. — 35 feet, 19 feet 4 inches, 20 feet, and 

 7 feet G inches span. It rests on a soHd rock of limestone ; the water in the 

 river flows through the large arcb, under which there is a deep chasm cut 



out of the rock 30 feet in depth, causeil by the incessant rushing of the 

 water from the falls above, wliich descend with great violence and rapidity, 

 falling, from the surface of the water at the Eel Weir to the level below, 15 

 feet in the distance of 100 feet in length. 



The arches are e\ idently too small in capacity for so great a body of water 

 rushing dpwn during tlic floods, at which times it shakes the bridge very 

 much, making it appear in danger of being carried away. 



I would recommend a new bridge being built at this place, in a more 

 direct line with the entrance of the town, with stone piers and abutments, 

 and a cast-iron arch of 100 feet span, witli two side arches of stone, 30 feet 

 span each. 



The Eel Weirs at the top of the fall are a great obstruction to the free 

 passage of the water, being built of stone, and forming solid walls about 4 

 feet 6 inches high, and 4 feet Ijroad at tlie base, by which means two-thirds 

 of the distance across the river is blocked up. These walls or weirs should 

 be cleared entirely away, and a wall erected about five or six inches below 

 the summer level, and 1,100 feet in length, according to the form described 

 on the drawings. The i)roposed site is a very favourable one for the purpose, 

 being of solid limestone rock — the surface will require very little levelling or 

 preparing, and upon an average one course of stone will be sufficient to build 

 the Dam from one end to another ; for this pmpose and also for b\iilding the 

 proposed bridge there is abundance of flat bedded stone on the spot. 



The falls of water at this place arc remarkably fine and well worth atten- 

 tion, as they present several such sites for mill power as are rarely to be met 

 with. 



The old corn mill at the end of the bridge, which is now working to great 

 disadvantage, will require to be removed (to make way for the proposed weir) 

 to a far better site to be selected. 



The three channels of the river course leading to tlie dam will require to be 

 deepened from one foot six inclies to two feet, which can easily be effected, 

 to allow the water to flow freely to the dam ; also tlie point of rock below 

 the line of the proposed dam should be taken oft" to allow the water to escape 

 to the chasm below. Above the dam there are several good sites for landing 

 places and quays for Steam Packets and Trade Boats. 



The channel of the river from Belleek to Roscor, entering the lake is fine, 

 and strait, and of sufficient width. Tliere are several shoals which are com- 

 posed of gravel and clay, besides the Carry Eel Weir, which is similar to the 

 one at Belleek, (formed of stone) and dams up the water in a much greater 

 degree, causing a head of from one foot six inches to two feet during the 

 floods. 



The above shoals and Eel W"eirs require to be removed to the breadth and 

 depth sliown on the plans and sections, ^■iz., 200 feet wide, and seven feet deep. 



Tlie shoal at Portora is formed of gravel and clay, and will require to be 

 deepened as shown on tlie plan and section. 



The West bridge at Enniskillen is of recent construction, and built of rub- 

 ble masonry, ashlar quoins and arch stones, string courses and parapet for 

 fixing the railing ; it has three arches of 45 feet inches span each ; segments 

 of circles rise 15 feet G inches, and 19 feet 6 inches in height from the sur- 

 face of water to soflit of arches ; piers are 1 1 feet thick. I was informed by 

 Mr. Maguirc, the builder, that the west abutment is sunk G feet under the 

 bed of tlie river, and the other abutment and the two piers 3 feet. The 

 water-way under the arclies is very shallow, and the piers and east abutment 

 would require under-pinning, as shown in the elevation; and the channel 

 both above and below the bridge, as well as under it, requires deepening from 

 opposite tlie Castle to the deej) water near the Distilleries below the bridge. 



There are several encroachments on the river at this place, in the shape of 

 walls and quays, which should be taken down, so as to give the river its ori- 

 ginal sectional area. 



The East bridge is an old structure and built of rubble masonrj', it is com- 

 posed of five arches of the following dimensions, viz., 22 feet 3 inches; 24 

 feet ; 23 feet ; 2G feet ; and 21 feet span, and from the surface of the water 

 to the soffit of the arches is 17 feet in height. At this time nearly all the 

 arches were dry, with the exception of one of them, through which small 

 boats might pass. I would recommend the bed of the river under the arches 

 to be deepened and the piers under-pinned. 



There are several shoals in tlie river in the East Channel, which require 

 deepening, particularly at Boston's Ford. 



The Eel Weirs at Dane's Weirs appear very formidable erections which 

 ■ilmost choke up the channel of the river, merely leaving a small space of 

 about 20 feet in w idth for the boats to pass through. In other respects, also, 

 it forms a very diflicult channel for the Navigation at any time ; but particu- 

 larly so in the winter season ; and when the head of water is great, and is 

 necessarily attended with much danger to the boats navigating up and down 

 stream. In summer the boats are required to be lightened, in order that 

 they may be enabled to pass over the shoal. The Eel Weirs are constructed 

 according to the form represented on the plan, and composed of piles, stakes, 

 &c., and made to close with wattles, &c., that few fish can pass through the 

 eyes or gaps. The bed of the river where the Weirs are erected is very 

 shallow, and is composed of clay and gravel. 



The banks of the river at this place are high and slope towards the river's 

 edge. 



This shoal and Eel Weir, and the shoal and contraction of the Bridges at 

 Enniskillen, are the principal obstructions in this quarter, and which cause 

 the lands and property on the Upper Lake to be inundated to a great extent 

 — these Eel Weirs to be cleared away, and the shoal deepened. 



