The state herald., 1892-03-11
SIMPLE EARrHEN DAMS.
Practical sugsessss.s - Farmers Build
ing Small Reservoirs for Irrigation.

CATION Age:
One Of tho first things to be done after tbs
site Is secured Is to make provision to draw Of
the water. Wooden boxes or cribs Of timber,
although sometimes used, are not to be recon-.
mcnded from the fact that they soon decay
and arc extremely difficult to replace, arc q
sort Of weakness to the reservoir and do not
admit Of easily inserting q gate which can bc
freely operated. Stone culverts, laid In
,cmcnt, are costly and substantial as rule
but require a special gate which may give
trouble. Piping, Of which there arc several
kinds in the market, Is perhaps the most
suitable and by its use one can purchase the
standard low pressure water valves, such as
are in use In city water works, that are guar
antecd to give satisfaction.
In most makes one can order valves with
sockets for u long rod which would be used
on the inside Of reservoirs and Of sufficient
length TO reach above high water where
hand wheel is attached. It is much safer to
place all valves or stop gates near the inner
end Of the piping.
Where water free Of sediment Is wanted as
for city use the outlet pipe Is placed two OF
more feet above the bottom with drain pipe
Mt tho lowest point to flush ont the sediment,
but for irrigation II may be placed Mt the bot
tom. In laying the pipe care must be taken
70 provide safe and continuous bearing be-
meath 1t, otherwise the load imposed by the
earth above will cause portions to settle and so
loosen the joints. 1t Is necessary, too, TO dig
one or more cross trenches from the pipe and
pack them full Of cement concrete, clay or
good cafthen puddle, bringing the same up
two or more feet above the pipe so as to arrest
any leakage along the outlet pipe. The sur
face upon which cmbankments arc to rest
should be plowcd and the roots Of brush and
weeds removed to. the outer toe Of the slope
after which the ground is again plowed and
trench dug along the center of each cmbank.
mcnt When this much Is done water should
be applied. The writer considers the abund-
ant use Of water Of prime Importance
In all works Of this nature
Usually 1t can be conveyed TO the site through
| ilume or pipe and made to discharge at a
height equal to the top Of the cmbankmont
when finished
| As the contents OF the scrapcrs, carts or
wagons are dumped on the fill, have them
thoroughly sprinkled by an ordinary street
sprinkling wagon. II such Is not available, II
good substitute may be made out of u large
barrel or redwood plank box with piece OF
perforated pipe for sprinkler, controlled by
hinged flap valve faced with leather. II the
material Is still too dry to pack well, it is ad.
visablc to sprinkle or wet In some way the ma
tcrial before taken from the pit. As the fill
| rises more water Is turned Into the trench 81
that the whole base presents the appearance
of two low, wide cmbankments, with .
canal of water between. The better way,
theoretically, would be to allow both halves Of
the base TO slope up stream, but. 1t is some
what difficult to do this In practice and the
plan followed by the writer has been TO ALLOW
both sides to slope toward the canal In the
center. BY so doing the material is readily
crowded into the water and the outer edge.
being highest, the whole top can be flooded II
necessary, when the teams are not working.
| BY building in water In the center one SC
cures practically the same results as with Q
core Of puddled clay, concrete, or masonry
without the serious disadvantage OF joint OF
| each side Of such core, which often proves
fatal To tire structure By the other way thert
are no distinct joints, since the water In the
canal pcrcolatcs quite n distance on cacf
side, and these half cmbankmcnts are wateret
by sprinkler and packed by the passage o
the teams into mass nearly rs compact u.
that done under water.
Another suggestion to those inexperienced
In such work may be made, In relation to tn,
sorting Of the materials. In nearly every cas-,
dlffcr, RUNNING from fine to coarse and fron
porus to impcrvious, and successful practlc,
requires the placing Of that which Is the bes
adapted to retain water next To the edge Of tn,
water, or on the inner half, while the rocks
larger gravel and heavy substances In genera
arc ranged from the outside toward the cen
ter ON the outer half.
In storing water for Irrigation II Is advisable
TO make the slopes particularly the Inner ono
quite fiat and To protect II where Il Is liable Il
wash by riprapping with rock or Stag, or lininI
with lumber
| Notwithstanding all these precautions,
there Is not sufficient space for the water, II
great floods, to escape other than over the tol
| Of the dam, washout Is inevitable. In mani
| proposed sites n narrow rocky ridge can b
blasted Oh down TO level Of the surface o
the water In the reservoir when full. In othe
sites an carthcn bank may he cxcayatcd dow
Ia similar level, aud the surplus waite
wasted through a short, Wide canal made To-
that purpose, having as steep n grade Ms III,
nature Of the earth will permit. II the ma
| tcrlal Is not suitable humc Of some kind vii
answer all requirements, aud In deciding upol
iis area II Is well to figure up the total maxi
mum now Of the surplus water which is eve
likely To flow through this flume, and then /,
make II as large again as such volume ~
quircs.