316 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 
in a very shallow layer, applied continuously for a considerable period of time, or in a 
deep layer for a short period. 
If the flooding take the form of a standing sheet of water, it may be quite deep, 
and be allowed to stand until it all settles into the ground and evaporates. A fourth 
method is to combine (he standing sheet with the (lowing one, allowing the water to 
stand for a short time ; then draw it oil' to "Some other portion of the held. This proc- 
ess is more applicable to large farms than any other method. It costs less, generally 
speaking, to prepare laud for irrigation by this process, and the work can be done 
more quickly. But it is applicable only to lands of gentle, even slopes, and a soil 
which does not cake after beiug soaked. A large volume of water, comparatively 
speaking, is required, and there is danger of great waste, unless the irrigator be a man 
of experience and the ground be well prepared There are, however, many crops for 
which this method is not the best. 
Thesecond method — by ditching — is also varied, to a considerable extent, in practice. 
It may be carried, flowing constantly, between the rows of plants, whence it perco- 
lates laterally through the intervening soil, or the water may be kept standing in 
ditches between the rows. In this case the ditches should be larger and further apart 
than in the previous case. In the case of very open, sandy soils, ditches may be led 
along the divides, or ridges, at greater or less distances apart, the lateral percolation, 
or seepage, being sufficient to carry the water over the whole ground. 
The ditching method has great advantages over the flooding method in some re- 
spects. It costs, iu general, very much less to prepare the land and to apply the water. 
On the other hand, it is ordinarily less economical of water, and requires more time 
in the application of it. 
The third and fourth methods are not. and probably never will be, in use on any 
considerable scale, for reasons too obvious to mention. 
It is impossible to form any estimate whatever of the amount of money at present 
invested iu irrigation works, as there arc very few aud very scattering statistics on thin 
subject, and it is not a subject upon which inferences can be drawn from the known 
to the unknown. Still less can any estimate be made of the amount which would be 
required to construct works which would utilize all the water flowing in the streams 
and thus bring the maximum of land under cultivation. Such au estimate, even 
in the roughest form, must await the result of detailed surveys, and the development 
of definite plans. 
During the past few years fertile brains have been busied very extensively in devis- 
ing ways and means for spending money to no purpose on grand schemes of reservoirs 
and ditches. These schemes have come from all grades of authority, from an ex- 
President of the United States, who knew nothing about it, down to <i county surveyor, 
who ought to have known better. 
None of the streams of the West carry .sufficient water, or command land in suffi- 
cient amount, to warrant the construction of any single great work in the form of 
reservoirs or irrigating canals. The fall of those streams is. almost without ex- 
ception, sufficiently great to allow the water to be taken up to the bluff lands by a 
very few miles of ditch. As the primary and almost sole object of a long canal, 
parallel to the stream is to save fall, so as to command the country, it will be seen 
that such canals are doubly unnecessary iu this region. 
When the arable lands of the arid region arc developed to the utmost capacity of 
the streams, they should be distributed in the following general way. Along the base 
of each mountain range should be a strip of land parallel to the range, more or less 
continuous, and of greater or less width, iu proportion to the amount of water flow- 
ing from the mountains. Down each stream of any consequence would follow a belt 
of cultivated land. If the stream has a rapid fall the belt may be broad, and extend 
a comparatively short distance down its course. If its current be sluggish, the strip 
should be narrow, confined, perhaps, to the bottom-lands merely, and may extend 
down the stream a longdistance. The details would depend upon local circumstances. 
