The San Juan County index. (Aztec, N.M.) 1890-19??, 1904-06-03
SUBTERANEAN
RESERVOIRS
Development et Water in Dry
Stream Beds a Frequent
Recourse.

Development Of water in dry stream
beds is Of frequent recourse when the
bed is largely composed of sand, gravel
or rock derbis ct arious kinds. In the
arid regions espec ally the visible stream
is often only a fraction Of the water
moving along stream bed and when no
water is in sight there is frequently
considerable underhow during the dry
season. On larssAtreams water enough
has been intercepted to supply large
irrigation enterprises and in many cases
a small stream will yield a valuable
farm supply. The. fret thing to do is to
determine by prospect in the dry sea-
son whether al underflow exists
when the surface flow has ceased Sc
lecta point in the stream bed where it
seems to be confined to deep narrow
channel as well as IAN be judged by the
steep, rocky banks and excavate a hole
or well down to tha water ard open out
the bottom 30 rs tG obtain water sur
face like that in veil.
By observing this it can be determin-
ed whether water pocket or an under
ground stream hes been struck. In
case of stream the movement eau be
detected by the collection of light litter,
etc, on the downstream side or in case OF
considerable movement the flow of the
water can be detected by the action Of
the lighter sediment. II no movement
can be detected tn effect Of pumping
from the hole will give an idea OF the
amount Of water available by the length
OF time the hole will stand pumping,
Suppoeing the prospect is promising by
the tests applied, the stoppage OF the
underaow by submerged dam is the
next step. To construct this an excava.
tion must be made across the stream
bed to rock or hayr clay on the banks
and must be carried town to bedrock or
hardpan at the bottom Of the channel.
Ordinary precautions against caving
Of the sdes OF this vide trench must be
taken according e the nature of the
material tounc . water must be
tenporily ian,b. a1G forced to flow
r'..4.5dgn' Dol NJ 4,s,Gea. t..4t
est possible contact must be secured by
etfecting odsement in imprevious mate
rial at the sides and bottom. The dam
shoId be constructed OF concrete rich
in cement, the upstream fatg being vel
plastered with cement or with coating
OF asphatum if available. When the
work has set Tell, tie temporary escape
may be stopped and the loose material
replaced or both sides of the dam. The
top Of the dam usually rises sufficiently
above the stream bed to hold back q
certain depth OF visible water and t
oliver at level where it can bo conven
iently taken in to pipe or tlume anC
carried to a ditch below, where firu
ground Is reached. OF course the water
can often be taken out by an under
ground pipe from a low point in thI
dam it the grade to the point OF uee il
sharp enough.
Y Holding water by submerged dam
] has advantages. 1t employs subter.
| ranean reservoir and largely reduces los
by evaporation, which is 80 great il
= surface storage. 1t is also a reservoir
3 presumably with tight sides, else tn,
. prospect would not have shown suffic
!. lent water to impound. 1t is safe dan
] because it offers no resistance to fresh
= cts. II it lacks elevation for outflow, il
b. serves as fine cistern for pumping ant
3 conseryes water for that purpose.
point OF excellence in submerged dan
= is its perfect bedding and construction
2 30 as to be water-tight. This is moi
: always attained, especially when al
r attempt s made to intercept a rid,
s valley stream without definite bank
: and some submerged dams are not a
, efficient as calculated. In work on
+ small scale it is not advised to try an
b. experiment with such source. For tn
D farm supply the underground streau
d should be comparatively small and wei
confined on both sides. Denver Fi5lC
j. aud Farm.