The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1885-1921, 1906-08-18

/ e-1t's -fi taAC water EE1lzl I4ituTl1hT
] stream july Is, 1905. and found about
one-half cutie foot per second fiowine
| over.yyelr- As the rains fer several t!aVs
| back We're up IS the average. / am in
| elined TO believe that the water avail
| able Tor sluieiag from the sources
| mentioned, could not be depended upon
| for more than one cubic foot per second
ana TINS for about two-thirds of the
time.
Estimating twelve per cent, which
| IS the best average we could make I'M
der similar circumstances at Wahiawa,
II would take sixteen months to put in
the 100000 yards for the dam.
Although the above conditions are
not favorable for sluicing, the earth
can be put in cheaper by this method
and 1t Is easier to secure a good piece
of work that will be uniform through
out the whole section.
An abundant supply of rock can be
obtained on the side hill about 1000
feet from the dam. which will be suit
able for the rock fill and can be
brought down very cheaply There
fore, taking this fact into considera-
ton, together with the shortage of
water and the necessity for good drain
age, / have decided that the most feas-
able and economical plan is TO put in
rock fill across the main canon between
sections 9 and 11+10 for the back slope
of the dam.
At the pit sunk over the point termed
mushpile - at Station 8+T5. the plas-
tic material before referred to was
reached at the go foot level. An open
formation containing per cent. of
rotten rock lies Immediately over it,
with a strata of volcanic sand, as al
ready described. which carries consid-
cradle ground water. l found the plas-
tic material nine feet in depth over the
rock upon which the concrete core wall
across the canon rests This was quite
soft owing to the accumulation of
water in the trench. Therefore, from
Station 8-r22 to Station 9, / would
recommend that the earth be removed
on the back side of the core down to
the $50 foot level and fine crushed rock
be tamped into the plastic material
until it becomes perfectly solid under
heavy tamper.
a strata of pure rock twelve inches
IN thickness shall then be put in place
across the width of the trench to pro-
vide for drainage and at the end of
the concrete core wall, a four-inch pipe
projections eighteen inches mauka of
the core and surrounded with an eigh-
teeninch thickness of fine rock. The
trench behind the wooden core shall
then be filed as before.
From Station lilo to 11+60, after
filing the trench with good quality of
earth on the makai side up to the 963
foot level. put III a strata of fine rock
eighteen inches in thickness and fill
with earth to the top
At the Waikiki end Of the concrete
about Station 10+50, place 4-inch !
pipe through the core wall, projecting
eighteen inches mauka from the core, |
covering the end with eighteen inches |
thickness of fine rock.
SECTION OF DAM; BE-
TWEEN STATIONS AND lilo.
From holes I had drilled near the
upper toe of the dam, | find there is a !
con gIomerate mass of earth and rock |
about sixteen feet in thickness, over |
lying a strata of hard earth and rock |
of varying thickness. over the strata |
of hard rock which was found at the |
foot of the core wall on center line of |
dam. OWING TO THE FACT THAT |
THIS IS MORE OR LESS OPEN, |
AND PORUS, | deem it advisable to |
put in cutoff wall, as shown on the |
plans. This could be made out of sheet |
piling but more satisfactory plan,
which would cost very little more.
would be to DIG A TRENCH ABOUT /
FIVE FEET IN WIDTH DOWN TO
SOLID FORMATION, AND PUT IN
A SHEETING OF PLANK ON THE
MAKAI SIDE, TOWARDS THE DAM,
3AULKING ALL THE CRACKS in
he same and placing about fourteen
inches of concrete on the bottom next
o plank and then filling the trench
With a good puddle material. The top
If these planks should be carried to
he 966 foot level and the length of
sheeting should be about Us feet,
well into the bank on either
ide.
BASE OF THE DAM:
The whole base of the dam should
,e stripped to depth of not less than
ourteen inches. The sides of the canon
hould be stepped into benches. The
critical rising being not less than two
nd half feet, said steps to be as ir
egular as possible; WHILE THIS
LAY APPEAR TO BE AN UNNEC-
1SSARY PROBATION, IT'S I'M
'ORTANCE CANNOT BE OVER
4OOKED in securing a contact and
ond with the natural formation.
,oRE WALL:
While statistics show that pine i'm
edded in earth and saturated with
Tater, is practically indestructible, 1t
oes not commend itself to me IN
tructure of this kind, where there
light be possibility of drying out to
certain extent, during periods of low
-ater. but on the shallow sections of
ne dam, at the ends, the portion in the
ore trench will at all times be entirely I
lbmerged and in the made portion OF '
le dam, it will have served its pur-
ose in compacting the puddle during
I
But across the central section OF 5
lie dam now under consideration, L n
link A BETTER AND STRONGER c
is DEMANDED. /
he present construction with two c
icknesses of 2x12 inch plank and I
a inch posts spaced FIVE feet apart is a
OF STRONG ENOUGH.
In the WahiayNa dam TWO fhickneSSeS II