EROSION AT SUMNER.

Press, Volume LXVI, Issue 20024, 4 September 1930, Page 13

EROSION AT SUMNER.

TO THB E3ITOB OF THB PBESS Sir,—On Saturday afternoon last I sat in my car on Scarborough Head and noticed the tremendous changes that have taken place in Sumner from Shag Rock to the old baths under Scarborough. I belieye the primary cause of these changes and the scouring of the sandhills to be the tramway causeway under the cliffs of Clifton, and the secondary cause to be that part of the Esplanade east of the jetty, and the consequent sealing of the narrow channel, between Cave Hock and what I, as a boy, knew as Castle Rock, through which the sea had a free run at high tide. First take the causeway. Before this was built, the estuary at low tide used to flow close • up to the roadway rcund the small bay under the cliffs, close past the western end of the tram bridge, thence in a continuous curve under the jetty and so out to sea in

a north-north-easterly direction. The causeway was built, and naturally the water of the estuary was pushed over towards New Brighton; and soon a portion of the water made a shallow outlet between New Brighton beach and the sandbank that ran out to the bar. At the end of New Brighton beach was a naval reserve of- fifty acres, I believe. This consisted of very high sandhills; but in March, 1918, I think, a heavy easterly gale drove the tide up the estuary with such force as to sweep away acres of these sandhills. This was the day on which some of the. boats anchored at Redcliffs were washed across the road on to the rifle range.. From then on the shallow outlet; I speak of above became deeper and. carried more water out' to sea, apart from the main stream. Now take that portion of the Esplanade east of the jetty. This at high tide had the same effect as the causeway, in pushing the water back on to itself, as it prevented the free range of tlie sea, through and round the Cave Rock, which • used to take place very frequently in the course of each

year. Pushing the water back in this way must naturally have . gradually forced the current of the estuary over towards New Brighton in this locality also. In course - of time the sandbank, between the smaller and larger channels, was washed away and, the stream now has a perfectly; straight run out to 'sea-' from Shag Kock, in almost an easterly direction, instead of the long continuous curveit used to have. (This shows up very plainly from Scarborough Head-at low tide, as it was on Saturday.) i The current therefore now flows partially across Sumner bay in a direction just off Scarborough Head, and on the inside of this current is forming a sandbank right out into the bay. This must have the effect of narrowing the entrance for the tide into the'bay, and the strongest flow of it. is therefore along the foot of Scarborough, on to the beach at the ends of Head and Eiiston streets. The trend of the. tide .is-then' along the beach towards- Cave>Rock, carrying with it the sand which it has scoured away and .which goes'towards making up the sandbank already referred to as forming between the-esta-

I ary stream; and the beach just east of' Cave Bock. .... ~.-., , > ..>. ■ I have known Sumnerpintimately for* the past forty-odd "years and feel that, my conclusions are very., near, the mark.—Yours, etc., '.. OBSERVER. September 3rd, 1930.