Book III. IRRIGATION. 661 



small streams, and even in the drains and feeders of a water meadow. Wherever 

 the channels are so constructed as to make a fall, or much increase the rapidity of the 

 stream, it is constantly disposed to wear away the sides of its channel or undermine a 

 dam. To repair these defects, land must be dug away and wasted each time it is re- 

 placed with the loss of labor. The consequent ill management of the water renders it 

 more advisable, and perhaps cheaper, to make all such works of masonry. When works 

 are well done at first the owner ever finds much pleasure in viewing them ; and even 

 the laborers feel much more interested in their good management. 



4099. The expenses of making a water meadow are not easily estimated. Much de- 

 pends on the original state of the ground, the size and fall of the streams to be used, the 

 cost of hatches and leYigth of the main feeders, which may be necessary for diverting the 

 water out of its original channel, and even upon the charge for levelling land, which 

 differs materially. Some soils are much harder and more ^fficult to move than others, 

 and in certain situations, building materials are very scarce and dear. This last circum- 

 stance must make a considerable variation in the price of the hatches, where the stream is 

 large. It is also impossible to tell with any degree of certainty, what proportion these ex- 

 penses should bear to the quantity of land irrigated, for some situations will require 

 much more masonry than others. 



4100. Before entering upon the execution of a water meadow, it is necessary to consider 

 fully, whether the stream of water to be made use of will admit of a temporary wear or 

 dam to be formed across it, so as to keep the water up to a proper level for covering the 

 land without flooding or injuring other adjoining grounds; or if the water be in its na- 

 tural state sufliciently high without a wear or dam ; or to be made so by taking it from 

 the stream higher up more towards its source ; and by the conductor keeping it up nearly 

 to its level till it comes upon the meadow or other ground. And still further, whether 

 the water can be drawn off the meadow or other ground in as rapid a manner as it is brought 

 on. And having in addition to these an attention to all such other difliculties and ob- 

 structions as may present themselves, from the lands being in lease through which it may be 

 necessary to cut or form the mains or grand carriers, from the water being necessary for turn- 

 ing mills, from the rivers or brooks not being wholly at the command of the irrigator, and 

 from small necks of land intervening, so as to prevent the work from being performed to 

 the greatest advantage, the operator may be in a situation to commence his operationsr. 



4101. 7/1 order to have an equal distribution and prevent waste, Spith states, that na 

 part of a meadow, either in catch -work or beds, should be so formed as to be floated di- 

 rectly from the main feeder ; but all the main feeders should be kejU high enough to 

 discharge the water into the small feeders with considerable velocity and through a nar- 

 row opening. The motion of water is truly mechanical ; it requires a great deal of 

 ingenuity, and a perfect knowledge of lines and levels to make it move over the ground 

 in a proper manner. No two pieces of land being exactly alike, renders it still more 

 difl[icult to set out a water meadow ; but even if the figure of two pieces be alike, the 

 inequalities of surface will probably vary. Each meadow, therefore, requires a different 

 design, unless the land owner makes up his mind to the heavy expenses of paring off 

 banks, and filling up such hollows as may be necessary to reduce it to some regular me- 

 thod. The construction to be varied according to the nature of the ground. This 

 constitutes the diflerence between the water meadows of Berkshire and Devonshire. 

 Those of the latter are upon small streams carried round the sides of the hills, and are 

 chiefly catch-work ; those of the former being near large rivers and boggy ground, arc 

 thrown up into ridges to create a brisk motion in the Avater, and also for the essential 

 purpose of draining off all superfluous moisture, which might be injurious to the grasses 

 when shut up for feeding or mowing. Where there is much floating to be done with a 

 little water, or rather where the great fall of a small stream will admit of its being car- 

 ried over a vast quantity of ground and used several times, it is desirable to employ it in 

 such a way that the meadows so irrigated must not be exhibited as perfect models. 

 If it should answer the purpose of a coat of manure upon such an extent of ground, 

 it is all that can be expected, and will amply repay the expense. Losing fall is wasting 

 water. 



4102. The drains of a water meadoiv require no greater declivity than is necessary to 

 carry the water from the surface, therefore the water ought to be collected and used again 

 at every three feet of the fall, if it be not catch-work. It is sometimes difl^cult to do 

 this in bed-work meads, but where the upper part of the meadow is catch-work or in 

 level beds, and the lower part not too much elevated, it may be done. By collecting 

 and using the water again in the same piece of ground before it falls into tl-.e brook, a set 

 of hatches is saved, and it is not necessary to be very particular about getting the upper ynrt 

 into high ridges, since that part of the meadow which is near the hatches generally be- 

 comes tlie best, and the lowe^ end of the field being often the wettest or most boggy in 

 its original state, requires to be thrown up the highest. If the land is of a dry absorben% 



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