IRRIGATION. 



which is allowed to pass by unheeded, 

 to be lost in some marsh, or eventually 

 in the ocean ! It is true, that, in some 

 parts, irrigation is not understood ; and, 

 that it is not always practicable to ob- 

 tain proper assistance ; whence many, 

 who would willingly water their mea- 

 dows, are prevented from taking- advan- 

 tage of streams capable of effecting the 

 intention. For the benefit of such per- 

 sons, in particular, as well as of our rea- 

 ders in general, we shall endeavour to 

 simplify, even this simple process, in such 

 a manner as may prove perfectly intelli- 

 gible ; and, by showing with what ease 

 irrigation may be carried on, induce a 

 portion of our landholders to attempt, 

 even without professional aid, or the tui- 

 tion of experienced persons, that reten- 

 tion and gradual distribution of waters, 

 whose sources are sufficiently elevated, 

 which may favour such a slight and 

 temporary inundation, as may give vigour 

 and freshness both to the soil and to its 

 produce. 



We shall divide this subject into two 

 distinct heads, viz. simple and compound 

 irrigation ; observing that the former may 

 be practical in various modes separately, 

 as will be shown, and that they may be 

 blended so as to come under the second 

 term. We shall also, by way of prepara- 

 tion, give the reader an insight into some 

 modes of cutting off, or of supplying wa- 

 ter, from sources of different heights, 

 and under different circumstances : by 

 this means, with a moderate portion of 

 judgment, the novice in this art may 

 speedily acquire sufficient of the princi- 

 ples to answer his own purposes, at least, 

 if not to form a correct opinion of most of 

 the cases which may come under his ob- 

 servation. 



The greatest difficulty we generally ex- 

 perience is, from the water lying below 

 the level of the lands over which it is to 

 be conducted. In many instances, the 

 springs whence streams are fed, lie wry 

 deep ; and, though copious, for want of a 

 sufficient inclination of their beds, move 

 very slowly. In other parts, jealousy of 

 improvement, personal enmity, the owner 

 being a minor, or insane, and the pro- 

 perty in the hands of trustees, or the es- 

 tate being in Chancery, mortgaged, &c 

 perhaps debars the possibility of taking 

 advantage of some peculiarly favourable 

 fall, from which the water might be 

 conducted with perfect facility and ef- 

 fect, over inclined planes, which, by their 

 sterility, seem to reproach the owner with 

 neglect ! 



In treating this subject, we must sup- 

 pose the speculator to be a free agent, 

 not shackled by such an unhappy neigh- 

 bourhood ; and content ourselves with 

 cautioning him not to injure the property 

 of others, such as mills, bleaching grounds 

 below the lands, &c. &c., by drawing off 

 that water on which their very existence 

 depends : a want of attention to this par- 

 ticular, has ruined many a deserving and 

 enterprising individual, and converted a 

 blessing into a serious mischief! 



Where the stream is rapid, the bed has 

 usually a very marked declivity, such as 

 admits of throwing the water over the 

 lands, and of withdrawing them when 

 they have flowed, in every part, to a suf- 

 ficient height. The first step towards 

 this, is to hold it up by means of a dam 

 or weir, laid across the stream, (if its 

 breadth admit, and that it be not naviga- 

 ble), so that, in the first place, the level 

 may be raised as circumstances may ad- 

 mit. In this, it will be necessary to 

 guard against injury to the property of 

 other persons above the dam; for the 

 raising a head of water, by means of a 

 dam, might subject lands, which before 

 were perfectly dry, to be inundated ; and, 

 even though such should actually prove 

 beneficial thereto, the owners might re- 

 cover in a court of law, under various 

 pleas of damage. ^ 



The water should, if practicable, be 

 raised to one foot, at least, above the 

 level of the highest land to be irrigated ; 

 because that depth may be then kept as 

 a surplus, in case of long-continued 

 ell-ought; being let in upon the first drain 

 by a very small penstock, made only to 

 the depth of the first level. The water, 

 when abundant, may flow both into the 

 upper level, and over the weir, so as to 

 make a fall. When the water is not 

 wanted over the land, the penstock may 

 be shut up altogether. It is to be re- 

 marked, that authors of eminence in this 

 brunch differ in opinion, though some 

 suppose water to be more richly impreg- 

 nated with vegetable sustenance, in pro- 

 portion as it is taken nearer to the spring; 

 provided the water be clear. The lands 

 over which it is made to flow, will be 

 benefited in exact proportion as they may 

 be near to the first level, which w'ill al- 

 ways receive the most obvious benefit. 

 In foul streams, the result is usually found 

 to be in an inverse ratio ; the water 

 being richer, in proportion as it is more 

 remote from its source, but the first level 

 will still receive the greatest portion of 

 the benefit. Where rivers are very mud- 



