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the upper parts of the bank fall in, a process which is
immensely accelerated by the action of a swell from the
sea, which extends a considerable distance up the river,
and causes, at every flow of the tide, a tolerably heavy
surf to beat against the upright bank. The action of
this is to undermine the bank about 6 to 7 feet
below its surface, and to cause large masses of it to
fall in, which are gradually crumbled away by
the surf, or carried away bodily by the next
flood. This action of the surf, if left to itself, would
be to form a flattish shore to the river bank, and its
destructive effect (apart from floods) could be
arrested by simple and comparatively inexpensive
means.

It remains then to point out some means by which
the scour during floods can also be arrested, and this
being accomplished, the safety of the banks will be
secured.

The ordinary piled and planked breastwork, well
filled in behind, would appear to be calculated to
resist both destroying agencies, were it put down
deep enough, but it would require to be carried out
in such a way and on such a scale, as would render it
very costly; for, although I have stated 30 feet as the
greatest depth of scour at low water, as yet experi-
enced, this by no means points out the extreme limit
which should be provided for, judging from the
extremely treacherous and shifting nature of the
river bottom, which appears to be little better than
quicksand during floods.

The peculiar form of breastwork I should recom-
mend, were this plan of protection adopted, would
be to drive piles, at least 60 feet long, on a moderate
inclination, all along the face of the work at a distance
of about 3 feet from centre to centre, the top ends
being surmounted by a capping piece, and strength-
ened by land ties.

Behind these I should fill in large pieces of rock,
forming, in fact, a rough stone wall, say of 4 feet in
thickness, and in front of the piles would also lay in
an angle or footing of rocks, to resist the downward
scour of the water.

These, as well as the rocks behind the piles, would
gradually settle during the first few floods till they
became firmly bedded and immovable.

The permanence of this work would be limited
only by the decay of the timber used in its construc-
tion.

I have not yet ascertained, but search is now being
made to determine, whether rock can be obtained at
an available distance from Westport; I have hopes
that it may be found in a spur near the Orowaiti, and
within say two miles of the port.

Assuming that a supply can be got from this place,
I should estimate the cost of this breastwork at about
£200 per chain.

Another plan, and one, I think, most worthy of
consideration, would be to throw out from the river
bank, at a safe distance above the town, a projecting
groin of such a character, as would withstand any
flood, however severe, and of such a size and shape
as would deflect the current sufficiently to protect
the line of bank below from scour, and render the
water below it comparatively still.

This being accomplished, we should then have to
deal only with the destroying action of the surf,
already described, from which the bank might be
protected by a low breastwork of piles and planks,
backed with stones and rock, which would also form
an enduring edge to the bank, and protect it as well
from the effects of traffic, &c.

The cost of this would be about £30 to £40 per
chain.

As regards the construction of the groin itself, I have
been forced to the conclusion, from careful observations,
that any work depending on the use of piles, however
well strengthened and braced, will be found insufficient
to withstand the forces brought to bear against it in
heavy floods, and we must look to the use of some
other material, in order to resist successfully the
power of the river. I can confidently recommend
heavy rock-work for this purpose as a certain means
of attaining the desired object—and with it a solid
substantial groin could be formed, which would resist
the action of the stream, and deflect the current to
any desired extent.

The manner of constructing it would be simple
and safe; the tramway laid for the supply of stone
would be continued to the edge of the river bank,
and the stone itself in large masses would be tipped
out of the trucks and left to find its own bed; the
tramway being extended along the groin itself as the
work progressed.

We have examples of groins thus formed naturally,
both in the Buller and the Grey, by the action of
tributary streams forcing masses of stone and rocks
of all sizes into the main stream during floods, and
which successfully withstand the heaviest floods in
the main river.

A frequent inspection of these natural groins, and
the manner in which they resist and divert the stream,
has convinced me of the fitness of such a structure
for the purpose intended. I estimate the cost of such
a groin, projecting say 2½ chains from the edge of the
bank, at a proper angle at about £4000. Its position
would be opposite Henley-street, that is, about 33
chains above Gladstone-street. Should its action in
stilling the water below it not reach as far as Glad-
stone-street, a smaller groin of the same character
might be run out about half-way between the two
places; and were it at any time thought desirable to
control the action of the surf rolling into the river, it
could be accomplished by constructing another imme-
diately below Gladstone-street—where the channel
becomes much shallower.

I will now summarize the works which, with a
view to the greatest economy, combined with perma-
nence and certainty of action, I should recommend to
be undertaken for the defence of the river banks,
viz :—

Large stone Groin at Henley-street ... £4,000
Say 30 chains of Breastwork at £40 ... 1,200
Formation of Wooden Tramway, say
2 miles at £500 ... ... ... 1,000

£6,200
Middle Groin, if required, say ... 1,500
Lower do. do. say ... 2,500

While on the West Coast I took an opportunity of
examining the protective works in progress at Grey-
mouth, and also at Hokitika.

The former consists of about 51 chains of wooden
breastwork, formed of piles about 32 feet long, driven
6 feet apart, capped, and planked over, about 10 feet
down, to the water line; the whole being strength-
ened at intervals by land ties and braces. Between
this and the edge of the bank, about 30 feet, there
exists a triangular space; the river beach or slope
shelving from the street level to a depth of about 23
feet at the line of piles, giving about 13 feet of water
on this line. This space it is intended to fill up
entirely with brushwood, tree tops, branches and
logs, without any admixture of earth or gravel; and
it is expected that this will effectually prevent the
scour of the river banks, if not at once, gradually, as
the mass of brushwood settles down firmly on the
bottom.

There is a reasonable hope for the success of this