CO129-572-3 Jubilee Reservoir- Shing Mun- defect in Pineapple Pass Dam. For extracted photographs see CN 3-48.... 1-12-1937 - 15-6-1938 — Page 11

10

Enclosure No .1.

Hon. Director of Public Works.

1.

JUBILEE RESERVOIR - PINEAPPLE PASS DAM.

The Reservoir reached overflow le vel on 21st August

and has remained full since that date.

2.

In August slight bulging of the granite pitching

on the downstream face of Pineapple Pass Dam was observed.

This was considered to be due to irregular settlement of

the rock fill forming the backing of the Dam, and was not

viewed with great concern. Mr. Campbell reported this matter to Mr. Hull verbally early in September.

3.

On 17th September considerable settlement of the

earth bank and pitching on the upstream face was noticed and further movement of the pitching on the downstream face had undoubtedly occurred.

On 21st September I visited the Dam with Mr. Campbell, who had been making frequent visits. The settle- ment seemed rather serious and I arranged for sections

across both faces of the Dam to be taken weekly, to ascertain what further movement was taking place. It was also arranged to have a set of photographs taken.

5.

Eight prints, (six taken on 21st September, 1937, and two on 23rd September, 1937), accompany this minute. Copies have been supplied to Mr. Hull.

6.

I informed you of the position the same day and

you requested me to get in touch with Mr. Hull and visit

with him. I did so and we visited the Dam on 23rd September accompanied by Mr. Campbell.

7.

It was then observed, for the first time, that the Dam parapet was distinctly out of line, having a definite bulge downstream, roughly about the centre of the Dam. The parapet stands on top of the reinforced concrete core wall, constructed in the heart of the Dam, and it was at once suspected that the core wall on which the stability and watertightness of the Dam mainly depends, had failed.