148 Transactions,.—-Miscellaneous. 
thick. At Cranz, on the Baltic, rows of piles 8 x 8 inches and 10 to 12 feet 
long, spaced 18 inches apart, have been successful, with a breastwork of 
piles and fascines, Breastworks are often required in cases of low foreshore 
or where a cliff is exposed to rapid erosion by the sea. 
Beaches have also been successfully formed along the sea barriers of recla- 
mation works by means ofgroynes. At Sunderland, successive additions were 
made to the reclaimed area as the beach formed. In 1874-5 the author had 
charge of similar works at Ayr; a reclamation of 24 acres of foreshore for & 
dock was made, and six groynes with stone filling, each 150 feet in length 
and 250 feet apart (see figs. 8 and 4), were constructed along the line of sea 
barrier in order to collect a beach in front of it. In the first year after their 
erection a rise of two to three feet took place. With main piles, having a 
nett length of 81 lin. feet, the rate per yard run with scrub and stone filling, 
instead of wholly stone as shown in the drawing, would be 18,5, lin. feet 
main piles, 23 CBM timber in way-balks, walings, cross-ties, and planking, 
and 50 lbs. iron work in bolts, 83 lbs. spikes and 21 lbs. in shoes; scrub 
and stone filling 173 cubic yards. The cost of 6 groynes, each 66 lin. yards, 
would be about £5,800. 
On spits and low beaches exposed to encroachment, groynes require to be 
constructed first, and then rows of fascines and scrub can be placed with 
advantage along the crest of the beach. The serub placed along the beach 
at Hokitika probably assisted the accumulation of sand behind it; but 
without groynes it cannot affect the action of the sea at the foot of the beach 
where the erosion is greatest, and encroachment proceeds until the scrub is 
undermined. The rough cribwork groynes that Mr. Rochfort placed on the 
beach in 1867 and 1868* were efforts in the right direction, but a much 
greater length would be required for efficient protection. The formation of 
a broad beach upon which the waves can expend their force is of far greater 
importance than a high narrow ridge which must always be liable to be 
washed down by heavy seas. 
The fetch or reach of open sea is considerably greater here than at those 
places that I have mentioned, and the waves from that cause must be larger ; 
but the depth of water off Hokitika at 1 mile and 1 mile distance is 26 and 
42 feet, at Sunderland it is 27 and 52 feet; while the range of spring tides 
at Hokitika is 9 feet, and at Sunderland it is 14 feet 6 inches; and it must 
follow that the power of the waves are more broken here, having to pass. 
over shallower water. I believe the design shown in figs. 1 and 2 would be 
efficacious, and it has the merit of presenting the minimum amount of 
surface to the seas. 
* Seo Trans. N.Z, Inst., 1871, Vol. IV., p. 299. 
