1835.] 



FARMERS' REGISTER. 



301 



flat lands were more indented with ponds, and 

 disfigured with quagmires, than at present. This 

 cannot be ascribed to ditching, and draining oi' 

 low grounds of late years altogether, (for although 

 ditches drain ponds, they do not fill them up, un- 

 less a constant current [.asses through them,) but 

 ig chiefly to ploughing the hills, and re- 

 moving the trees from the low grounds, by the 

 trunks of which, the current is divided into nume- 

 rous channels, and around the roots of whit 

 holes are scooped out, to the great impoverish; 

 ment and disfiguration of the laud. 



At the termination of the ditch C, there is an 

 excellent draw-off for the water; (which is very 

 important in an effectual piece of work of this 

 kind) the old bed of the creek being there wide, 

 and nearly straight for a considerable distance: it 

 is also straight above, at the upper end, which af- 

 fords a good inlet, which is also very essential; so 

 that the water has a straight course now for about 

 a mile and a quarter, without obstructions. Any 

 one may see at once the advantage of a continua- 

 tion of the new channel below, and from the crook- 

 edness of this part of the creek, may form some 

 idea of the necessity of straightening the natural 

 beds of streams in general; for which purpose, this 

 part of the old channel was appended to the fi- 

 gure. Though my land below this point is very 

 little subject to inundation, except immedia. 

 the bends of the creek, it being for the most part 

 what is called "seconds," and of course out of the 

 reach of freshets. The advi d rived to the 



land below, by an extension of the ditch, might 

 not justify the expense, unless combined with 

 those resulting to the low grounds above, where 

 the effect would be greater. These two considera- 

 tions jointly, might justify perhaps, a continua- 

 tion. 



In regard to the execution of the work under 

 consideration, it does not differ materially from 

 what is in common practice. Figure 2, is design- 

 ed to exhibit at once, the manner of excavating 

 the earth, in cutting the ditch. It represents a 

 transverse section of the canal: h and jo represent 

 the sides of the canal; B B the bottom; h s p a line 

 drawn across the top to measure the ditch; s«oa 

 plumb line dropped from this to measure,the per- 

 pendicular depth of the ditch: oa section of the 

 little ditch, cut in the middle of the. bottom, B B, 

 of the canal. The object of cutting a canal oi' 

 this sort, that is to contain and carry as much wa- 

 ter as possible, depends on the form of this figure, 

 for the velocity on which the washing apd q\ 

 of water carried depends on it. The velocity de- 

 pends upon the narrowness of the bottom: but the 

 narrowness of the bottom depends (the width re- 

 maining the same) on the inclination of the sides, 

 or the angle they make with the bottom; there- 

 fore the velocity is as the inclination of the sides: 

 but the action on the sides and bottom depend on 

 the velocity, therefore the washing depends on the 

 narrowness of the bottom. So that it appears that 

 if the form of the figure was altered in such a 

 manner as that the sides would meet in an angle 

 at the middle of the bottom of the ditch, the ve- 

 locity of the water would be greatly increased. 

 But as this could not be practised in so large a 

 ditch, the sides ought to slope in such a manner as 

 to make the bottom not more than a fourth of the 

 width of the top. But it must be observed, that 

 if the velocity of the water depends on the incli- 



nation of the sides, the cavinii', which is a consid- 

 eration, depends on their perpendicular form; so 

 that the ditch ought to be cut in such a manner as 

 ' ine the two advantages derived from ca- 

 ving, and increased velocity of the water. The 

 fact that lite same volume of water would run 

 swifter by diminishing the width of the bottom, 

 induced me to collect the thin sheet of water run- 

 i the bottom B B of the canal, into a phan- 

 uel with a narrower bottom, o. But the e'ffei 

 produced by admitting the. current into the new 

 channel, we shall. notice more particularly hereaf- 

 ter, my object here being simply to show how the 

 work should be executed, without entering mi- 

 nutely into the reasons for it, or to enumerate the 

 t iges derived from it, which come more pro- 

 perly under our second division oi the subject. 

 The mouth of the ditch should be cut wider than 

 the other part of it, ibr 50 or ICO yards down — and 

 a stop made in the old channel. The next n 

 adopted, in point of importance to the canal, to 

 drain the land in question, was the cutting of the 

 margin ditch, and other smaller ditches and con- 

 ductors, already mentioned, a better idea of which 

 may be had by looking on the figure, than by any 

 verbal description, which would be unnecessarily 

 tedious — -when cur object is brevity, *vithout leav- 

 ing out essentials. Sufficient allusion however 

 will be made to them to show their design and im- 

 portance in the figure, as we pass on. 



Havit ; out the method adopted to drain 



and reclaim the land, we proceed — 



dly — To show the effects produced by 

 straightening the old channel, end the advantages 

 derived to the land through which it runs. Be- 

 o her advantages which we shall hereafter 

 enumerate, the two principal ones, in view of 

 which the work was undertaken, were completely 

 obtained; that is, a thorough drainage of the land, 

 and the reduction of freshets. 



The manner in which the ditch operates as a 

 drainer, and its absolute necessity in this body of 

 flats, to drain it effectually, will be first pointed 

 out. What, renders it necessary to drain a body 

 oi' land of any description, is the redundancy of 

 water, over what is necessary of that element, for 

 vegetation. This is of three sorts: rain, spring, 

 and pond waters; but as ponds are collections of 

 rain or spring water, they may be reduced to two 

 only. The method which has been adopted 

 to get rid of these, when in excess, is called 

 draining. The aqueducts generally necessary 

 to drain a body of flat land, are eight in number: 

 the main drain, or "main carrier," as it is some- 

 times called, (a term borrowed from the irrigation 

 of land,) margin ditch, surface ditches, grips, 

 trenches, or what are commonly called water-lur- 

 rows, pond ditches, pits or perlbraticns, and hill- 

 side trenches, (usually called conductors,) though 

 every ditch, or trench, which carries water is pro- 

 perly a conductor. The main carrier, is a large 

 ditch cut through the middle of the low grounds, 

 the object of which is to intersect all the subterra- 

 nean passages of water, or veins, that it may flow 

 off, and to answer the purpose of an outlet to the- 

 water, more particularly of the margin ditch. The 

 margin ditch is generally a crooked conductor, 

 opened either at the seam of the first and second 

 low grounds, or at the foot of the hill, at the mar- 

 gin of the first low grounds; the object of which 

 i is, to receive the water of the surface ditches, and 



