Dodge City times. [volume] (Dodge City, Kan.) 1876-1892, 1882-08-31

formation we take pleasure in furnishing eI-
tracts from the report Of the Commissioner
of Agriculture on Practical irrigation In
Colorado" submitted in the year ISL. We
shall give extracts from week to week.
THE HEAD MAIN DITCH.
This ditch is first marked out by the sur
veyor's stakes, usually 100 feet apart, and
fsilowed by a good pillow TO mark the line;
it is not essential TO follow the surveyor in
every minute turn of the line, a. the differ
cree Of level in 100 feet, at a fall OF 2! feet
to the miie, i. only about half an inch; so if
close approximation is arrived at, 1t will
be sufficient. The eye of an intelligent far
mer or team.ier can save quite distance in
a mile, by watching these corners, without
any loss of fall. When the line Of the
ditch is well marked, then return and run
parallel line to marx the width OF the ditch;
then the heavy disching pillow and scrsper
-hould be used Some very excellent ditch
.. are made, both in Europe and in the
United States, which make ditching very
easy job.
In regard to the size OF the ditch, calcu-
lation must be made as TO the number of
sores to irrigate; so inches for so acres
would usually suffice Tor ordinary farm
crops; garden crops want more; the rice
crop still more Then, again, other mat
tiers mus, be taken into consideration, such
"a the quality of the soil and the amount OF
evaporation and seepage. II it is very
sandy, more water must be used, "a il will
lose by percoiation more than an impervi-
GUS clay soil.
The amount Of evaporation il large
item in long ditch. Mr.. J. W. Smith, o..
Denver, one of the stockholders Of the
Platte Water C.nai company, informs me
that out Of about ], 700 inches of water at
one point in their ditch, not above 900 are
sold and utilized when il reaches point s
miles below; the remainder, about 200
incbee, is los, by evaporation and seepage.
This is a wide and shallow ditch. In some
places it il eight feet, in Others six, and
down 10 eighteen inches OF fall to the mile.
Il, isa well established principle that the
deeper the amount of water carried by a
ditch, in proportion TO its width, the less
fall il necessary. According to the best au-
thorities, velocity of seven or eight inches
per second is necessary TO prevent the de-
post Of slime and vegetable growth, and
about fifteen inches per second the deposit OF
sand Thus the mean velocity need not ex-
coed, over a shiny bed, s inches per second;
over a common clay bed, inches per
second; over river sand bed, 10 inches
per second; over gravelly bed, is inches
per SECOND.
A superficial observer might suppose thai
seepags is influenced very much by atmos-
pheric or even the waters own vertical
pressure; but il is not SC, except in very
minute degree. Let US remember that an
cak iume n channel water tight, holds
water without seepsge; fumes and channels
OF other material can be made impervious &c
sespage. There are many kinds OF mater.
ial used in the construction of bitches thai
viii proven, seepsge. and different materials
can be found ON a graduating scale, calcu-
lated upon acknowledged scientific formulas,
of every kind of porosiiy, intending white
sand, fine gravel, coarse gravel, shingle
email powders, up 10 large ones, through
which the water win percolste as through 4
seive. In fact, all soils are really selves OF
different degrees Of ineness.
Materials properly prepared can be found
other than wood, stone, iron, &c, which
will prevent the seepage Of water, at least tC
any great extent A ditch can be cor
structed over sand hill, where 50 inchei
will be lost in running 100 feet. The sam,
ditch can be prepared by artificial bottom
ing which will carry the 80 inches Of waite
for length of ten miles, with scarce an,
percepuble loss
A deeper ditch eau be run at less fall
thus economiEing surface exposed TO In
heat of the =uo's rays, and thereby decreas
ing the evaporation. In cons'ructin;
bitches Of a small fall, the deposit of slime
sand and Tegetstion diminishes the sectiona
ares. and impedes the current The,
should be always kept well cleaned. Tn
course OF ditch should be IS straight a