-2-
25
sufficiently advanced for an examination by our senior
partner
Mr. Binnie early in November.
-
Generally, the design - skeleton drawings of
which have been sent by Air Mail to Mr. Hull - embodies
a watertight concrete cut-off wall carried into the
solid rock which will be grouted as may be required.
Above ground the waterface will consist of a reinforced
concrete slab wall inclined at 1 horizontal to 3.4
vertical, resting against a concrete retaining wall,
which, in itself, will be supported by a rock embankment
on the downstream side formed of large "plums" and
crushed stone to give a pervious but adequate support to
the concrete retaining wall.
The foundations of the retaining wall and rock
embankment will not require to be founded on sound rock
as is the case with the cut-off wall, and the design is
so arranged that the concrete retaining wall and rock-fill
embankment are free to settle independently of the
reinforced concrete slab wall.
The site for the dam is some 200 feet
downstream of the large waterfall, and some 400 to 500
feet downstream of the various possible sites considered
above the waterfall. The selected site involves an
additional height of 50 feet as compared with a site above
the waterfall or some 275 feet above stream bed, but it is
definitely the most suitable having regard to foundation
conditions.
We have taken out an estimate of the cost, and
have no reason to anticipate that it will exceed our
/original