Charlevoix county herald. (East Jordan, Mich.) 189?-1953, 1904-11-05
Practical Advice
on Draining

HAVING ueclueu 10 III dill, AZ" $500
we go at it?
First. to do first-class work, IL IS
necessary to have drainers lever
mounted on tripod, an extension rou' 4
and a common surveyors chain. Az
tape line would answer, but the chaih
Is much more convenient as 1t is not
injured by being dragged around In
the wet Do not attempt to do any
draining without an instrument, or en-
gaging a surveyor; as it is Impossible
to do a first-class job by guess work,
unless you have fall of several inches
to the hundred feet or continuous
running water. Even then 1T is mucn
easier and quicker to have ditch LAID
out. Set instrument perfectly level ana
where you can see over the entire
tract to be drained, if that is practical;
If not, see where the lower end can be
seen and ascertain the comparative
elevation of the outlet and the tract
to be drained as far as can be seen.
Then move instrument to some oSl
point from which the balance of tSe,
tract can be seen. To get at the differ
ence in elevation Of your instrument
in the two sittings, set the rod at the
last point sighted from the first stand
and the difference in the indicated ele-
walton is the difference in elevation
sought for; then, if the elevation indi-
Gated from the first stand be ga feet
and from the second stand the same
point shows 7.9 feet the difference, 2.5
feet is the height of the second stand
above the first.
After going over the ground in a
rough way once or twice. one can
readily ascertain where the lowest
points are, and the amount of fall you
have between the lowest points Of the
upper section and the outlet. Now
measure with the chain and get the
distance from the outlet to the farthest
point, by the line of the proposed ditch.
Suppose the distance is 80 chains or
120 rods. You want depth of three
feet at the upper end, add to is
a fall of one-tenth of a foot to evch
chain, 80 tenths, which makes in all
six feet. If, on comparing this with
the difference in elevation. you find
this will bring you below where the
outlet must come, cut off one-half OF
the grade on the main ditch and raise
the laterals little if necessary II
this will not let you out, reduce the
grade one-half on the laterals, as good
work can be done with one-twentieth
of foot to the chain CA rods). II
there is greater fall than six feet,
simply keep the required depth and
give little more fall where land is
sloping.
Now as to stalking out the ditch. If
ground is nearly level, pegs about ~
feet long are most convenient If there
is considerable unevenness have as
sorted lengths. Pegs should be smooth
on one side at tops SO pencil marks
can be made on them. Start ~ the
outlet and measure with the chain, put
ting a peg at each length, then drive
them, the man at the instrument di-
recting the driver by motions of his
hand When the first one is driven set
the rod on it and adjust the target in
line with the instrument, then follow
up the ditch and drive as many as pos
sible to the same level. When it is
necessary to make a new elevation,
drive an extra one near the last one,
leaving it one foot higher, re-adjust
target and go on as before.
Next comes the markings. Suppose
the peg at the outlet is 375 feet above
where the bottom of the ditch is to be.
Subtract this from $50 feet and you
have 275 feet. Then write with a
heavy pencil 2.75 above the 3.75 below
on the peg. The lower figures indi-
cate the depth from top Of peg to bot
tom of ditch, and the upper figures the
distance from peg to grading line, the
sum of the two, $50 feet, indicat fthe
distance from bottom of ditch to Grad
ing line, also giving you check on the
correctness of your work. AS you go
up the ditch subtract from the lower
figures the amount of the grade and
add same to the upper set. The sum
Of both must always be the same.
If your ditch be very deep, it would
be necessary to set the lire more than
$50 feet from bottom, but this is a
very convenient height for ordinary
work. To set line, drive n post near
the first grade peg and another on OPP
posite side Of ditch or eight feet apart.
and with common spirit level set
straight edge board at the height in
dicated above the peg, and nail.
Set another similarly at second peg
and then draw common carpenters
line very tight from one to the other
and then put two supporting boards
across under the line to take up the
sag of the line. These may be sighted
over the tops of the first two to gdkhe
level. In digging it is desirablE to
straighten up the surface, If uneven.
the first time over, so one may dig a
full or partial length of spade each
successive time and still maintain the
same grade. To make the final finish
ing grade, use common tile SCOOP of
nroner size and q LIGHT nnln about