1837] 



FARMERS' REGISTER. 



62^ 



Draining Sheep Pastures, Sfd 

 Plate V. 



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/A 



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iiiiilipSiW^ 





' till! 





A A A A Open drain in the wet h«llow. 

 B B flooding trendies for irrigating the dry ground. 



The difliculty and expense of draining lakes 

 must depend on their depth, the nature of the 

 ground through which the drain has to be cut, 

 and the distance to whicii it must be carried, to ob- 

 tain the requisite fall and outlet. These circum- 

 stances are easily ascertained, by exploring the 

 depth of the water, and the materials to be cut 

 through, and by taking levels accordingly. W hen 

 this is done, an accurate estimate of the expense 

 can be formed; and when that is compared with 

 the probable result, the utility or impropriety of 

 the undertaking can then be determined. It may 

 often occur, that it ie preferable to make the cut for 

 draining a loch in a new and different direction 

 from that in which the water has its natural outlet, 

 and this can be readily ascertained by the means 

 that have been stated; Lakes have also been 

 drained by opening a mine or subterraneous tun- 

 nel from the nearest outlet to the level of the low- 

 est part of their bottom, and this may in some 

 cases be done at the least expense ; but in others, 

 it may be a hazardous, and sometimes a danger- 

 ous undertaking. In these cases, shafts or pits 

 should be sunk from the surface down to the mine, 

 at certain distances, which would give light, air, 

 and less risk during the operation. It may some- 

 times be advisable to arch the drain, and cover it 

 in when very deep, which adds to its security, in 

 situations vvhere the ground is soft, and liable to 

 fall in, and when it also lessens the labor of rais- 

 ing the stuff from the bottom, which must other- 

 wise be carried to a distance from the sides. By 

 this means, the width of the cut may be less ; and 

 as a few yards are arched, the stuff of the next 

 few yards is thrown above that part of the arch 

 last made ; and eo on, in this manner, through the 

 whole length of the line. 



That lakes may be drained by boring, or sinking 

 pits to some absorbent strata below, is impractica- 

 ble, on account of the great body ai' water, which 

 Vol. V— 67 



no pit, nor any numbef of auger holes, could re- 

 ceive. This, however, has been imagined by 

 some, and has been described in a treatise by the 

 late Dr. Anderson, but has never in any case been 

 put in practice. 



Besides lakes containing a great body of water^ 

 to which the foregoing observations particularly 

 apply, there are, in many parts of the country,' 

 bogs and watery morasses, surrounded by fertile 

 grounds, which it would be an object of no less 

 importance to drain. These are neither produced 

 by water rising in themselves, nor by that of 

 springs in the adjoining banks ; but became wet, 

 by an accumulation of rain water stagnating on 

 an impervious subsoil, through which it can have 

 no descent, and being surrounded by higher 

 ground, through which there is no vent nor natu- 

 ral discharge for the water. 



Such are commonly called land-locked bogs, or 

 morasses. In the eastern part of the county of 

 Peebles, there are many bogs of this description, 

 and some of them have been drained in the man- 

 ner to be described ; and on the estate of Mount- 

 Annan, in Dumfries-shire, General Dirom suc- 

 cessfully drained one of considerable extent, in a 

 similar manner. 



The situation of these bogs being often much 

 lower than the ground that surrounds and confines 

 them, the cutting a drain or conductor through the 

 bank, for conveying the water collected withirt/ 

 would be attended vvith an expense greater than 

 the value of the land when gained. The thick- 

 ness and closeness of the retaining stratum of clay 

 is olten such, that although the strata under it M 

 of a porous and absorbent nature, as rock, sand,- 

 or gravel, the water can find no passage by which 

 to descend ; and therefore, by its long stagnation 

 causing the decay of the coarse vegetation that is 

 produced, it forms a morass, equally soft, and less 

 productive than any spring bog, is seldom pastura 



