230 



THK CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



Jl'LY, 



navisralioii is rendered more dilTleult than at either of the fords below; 

 and, in clearing it, considerable works of excavation will be required. 

 In sj'ring tides the rise of the \v :t •;• at the lower end of this ford is IG 

 ft. It in., and at the upper end !'( ft. 4 in.: there is therefore a fall of 

 3 ft. 2 in., on a length of about 1150 yards, which occasions a rapid 

 at low water, when the river is in its summer state. In neap tides, 

 the ri?e is about 11 ft. 2 in. at the lower end, and S feet at tlie upper 

 end. The length of the channel intended to be excavated at this ford 

 is about liG i yards, and its breadth will, as already proposed, be 30 

 yards at the bottom. An average depth of cutting over its whole ex- 

 tent of about one foot u ill be required in order to give a depth of IS 

 feet at high water of spring tides. A perch is to be placed on the 

 larboard hand at the lower end of this ford, and a buoy at the upper 

 end. A perch must also be placed at Fallin Toint on the larboard 

 hand. In passing Polmaise and Scobliie's Pow, no difficulty occurs; 

 near Bannockburn, liowever, there is a bank where a perch will be re- 

 quired as a direction for the deepest-channel. 



Manor Ford, about two miles and a quarter above Bandeath, has an 

 irregidar and stoney bottom. At the lower end of this ford, the rise 

 in spring tides is 13 ft. >> in., and at the upper end 12 ft. G in. ; and in 

 neap tides about 8 feet and G ft. 10 in. respectively ; there is conse- 

 quently a fall at low water of 14 inches which occurs on a length of 

 GG6 yards, and produces a considerable rapid at this place. The ex- 

 tent of ford proposed to be cleared measures about G6G yards in length, 

 and the breadth and depth of tlie channel to be formed will be the 

 sane as that already specified. This will require an average cutting 

 of IS inches in depth. From the curved form of this channel, a perch 

 will require to be laid down on the larboard side, for each end of the 

 ford, and a buoy must be moored in a central position on the starboard 

 hand. 



The .Sow Ford is about three quarters of a mile above the Manor 

 Ford, the bottom is stoney and irregular, and its direction also forms a 

 curved line, but as the bottom presents fewer obstructions to the cur- 

 rent than the two fords immediately below, there is no visible rapid 

 at this place. Spring fides here give a rise of 11 ft. 9 in., and neap 

 tides (i ft. 9 in. It will be seen, on referring to the plan and section 

 that the works of excavation at the Sow Ford are not extensive. In- 

 stead of mooring buoys to point out the direction of the deepest water, 

 it is proposed to erect two perches, the one on the starboard and the 

 other upon the larboard hand. Wherever perches can hn introduced 

 they are considered preferable to buoys, vi'hich are more expensive 

 both in their first cost and future maintenance. 



The Abbey Ford is situate about a mile above the Sow Ford, and 

 has already been excavated to a limited extent with a view to its im- 

 provement ; but the excavation wants extension, both in breadth and 

 in depth, fo render it useful. The current here is still so much ob- 

 structed that it causes a considerable rapid when the river is in its 

 summer state ; the fall being no less than 2 ft. G in., on an extent of 

 about .'iOU yards. Spring tines rise, at the lower end of this ford, 11 

 ft. 6 in., and at the upper end only 9 feet; and neap fides rise G ft. 9 

 in. at the bottom, and 4 ft. 3 in. at the top. The length of the exca- 

 Tation will be about 565 yards, with a breadth of 30 yards, similar to 

 that of the other fords. The average depth of excavation, in order to 

 obtain 13 feet at high water of spring tides, will be about 2 feet. 

 Connected w ith this ford, two buoys are proposed to be moored on the 

 larboard hand, the one at the lower, and the other at the upper ex- 

 tremity of the ford ; and a perch must also be erected on the star- 

 board hand. 



The Town's Ford is situate about 500 yards above the Abbey Ford. 

 The foul ground at this place extends about 1000 yards in length, and 

 the works of excavation, in obtaining a navigable track, similar to that 

 of the other fords, will be jiroporfionally more extensive. Spring 

 tides rise only 7 ft. S in. at the Town's Ford, and neap tides about 3 

 feet. Its bottom is very irregular and rocky, forming a great obstruc- 

 tion to the trade of the town, and the navigation of the upper parts of 

 the river. The average depth of cutting at this ford will be 2 feet. 

 For pointing out the deepest water of the new channel which it is in- 

 tended to excavate, three buoys upon the larboard hand are considered 

 necessary. 



The results of the operations which the Reporter has described will 

 be to deejien the river at those points where the obstructions occur ; 

 and the depths which are intended to be obtained at high wafer of 

 spring tides are as follows at the various fords, viz.: — Turosk Ford, 

 22 feet; Cambus Ford, 20 feet ; Bandeath Ford, IS feet; Manor Ford, 

 IGfeet: Sow Ford, 15 feet; Abbev Ford, 13 feet; Town's Ford, 13 

 feet. 



By thus proportioning the depths at high water on each ford to its 

 distance from Stirling, it is expected that vessels drawing 13 feet will 

 have sufficient wafer over the lower fords at any period of Hood, and 

 will thus be enabled to reach Stirling at the very top of high water. 



and get the full advantage of the most favourable lime of tide in the 

 shallowest parts of the river. 



The shore, or quay of Stirling, extends 20o feet or thereby along 

 the right bank of the river, and consists of a breast-wall built iii a rude 

 manner with boulder stones, without the usual and necessary provision 

 of defenders or wooden stretchers to prevent vessels from receiving 

 injury while lying at their moorings. Vessels must consequently lie 

 off in the stream to the great inconvenience of the mariner and trader. 

 In any improvement, therefore, upon the navigation of the river, the 

 unserviceable state of the quay-wall at Stirling should not be forgotten ; 

 but measures should be taken fur rebuilding it, at least to some extent. 

 The accommodation on this wharf is also very circumscribed and de- 

 fective, but it may easily be extended and improved, as proposed to 

 the Magistrates by the Reporter some years since. The road from 

 the shore should also be formed on a more easy line of draught. It 

 would likewise ]>rove a great convenience to the southern parts of the 

 town and the lower districts of the county, if an additional wharf, and 

 a road from thence, were formed about the central part of the Town's 

 Ford ; as also proposed in the report above alluded to. In conclusion, 

 the. Reporter has to state as the general result of his inquiry, that it 

 appears, from the annexed estimate, that by an expenditure of about 

 £10,V26 4s. the fords of the Forth might be cleared, so as in spring 

 fides to admit the passage up to .Siirling of the ordinary class of mer- 

 chant vessels drawing about 13 feet water; and he cannot but think 

 the importance of sucli an improvement far outweighs the capital re- 

 quired for its attainment. The position and rising importance of 

 Stirling is too obvious to be longer neglected. It is the natitfal em- 

 porium of the Western Highlands, and lies in front of an extensive and 

 fertile district, containing many valuable waterfalls and other facilities 

 for the establishment of large manufactories. 



Robert Stevenson*. 



Abstract estimate of the probable expense of the works of excava- 

 tion, mooring buoys, and erecting perches or beacons in the several 

 fords and reaches, on the river Forth, between Alloa and Stirling, 

 agreeably fo the foregoing report. 



For the expense of works of excavation and removal of stuff, and 

 for mooring a buoy and erecting a perch connected with the reach 

 between Alloa and Throsk, - - - £ 72 1 



For works of excavation, &c., at Cambus Ford - 618 18 



For ditto ditto Bandeath Ford - 654 13 



For ditto ditto Manor Ford - 918 7 



For ditto ditto Sow Ford - 439 10 



For ditto ditto Abbev Ford - irsr IG 



For ditto ditto Town's Ford - 2747 5 



For works of masonry and for re-building and ex- 

 tending Stirling Quay .... I2u0 



£8438 10 

 Incidents on the above sum of £3438 10s., at 20 per 



cent. ...... 1687 14 



£10,126 4 



"0\ THE IMPROVEMENT OF RIVERS, &c." 



Sir — In your review last month of my Treatise on the Improvement 

 of the Navigation of Rivers, you have given an entirely erroneous 

 version of my views, by an unfortunate mal -arrangement of your quota- 

 tions. This has possibly arisen in the press, nevertheless every scienti- 

 fic or practical man must feel bound, after merely reading your review, 

 to pronounce the work quite undeserving of the approbation with 

 which you and other literary characters have been pleased to honour 

 it. 



In chapter 2, is my definition of the regimen, or state of those rivers 

 which are free from bars, and the plain inference to be drawn from 

 this chapter alone must be, inasmuch as " like causes produce like 

 effects," that we can only ensure the improvement of defective, or bar 

 rivers, by approximating their condition to that of those n hich are in 

 the required state. 



In chapter 3, I give a representation of those features of the regi- 

 men, or state of bar rivers, which mark the difference between them 

 and those which are free from bars. 



In chapter 7, " on the course to be adopted for the improvement of tie 

 dtplh on the bars of n'Ktvs, and in their chaniie/s," I state, " the reason- 

 ing in the preceding pages on the causes of the formation of bars, 

 suggests the course to be adopted for their amelioration, by the re- 

 moval of all those inner banks, or shoals, stretching like dams across 



