CONFIDENTIAL
NOTE
S
Additional Item
For consideration
on 8-8-67 as item 2A of the
Agenda.
Enclosure I
XCC(67)71
Copy No...... of 27
MEMORANDUM FOR EXECUTIVE COUNCIL
WATER SUPPLY FOSITION
Since the last paper on water supply was presented to Honourable Members on 11th July 1967 the position has become considerably more grave. This has resulted from the continued absence of seasonal rainfall, and from a demand, on the current supply pattern, considerably higher than was envisaged.
2
Demand has averaged slightly over 62 million gallons per day, and, allowing for the fact that the fall in consumption normally associated with the winter months ahead will be much less pronounced on severely restricted supply, and its effect will be counteracted by a natural increase in consump- tion with time, it now seems reasonable to assume, in planning, that 62 million gallons per day will have to be provided between now and next July, to maintain a 4 hours supply every fourth day, with the present concessions to industry, resettlement and standpipe users. (This figure can be compared with the figure of 36 M. G. D. used in 1963/64, and with our earlier estimate of 45 M. G. D. for this year).
3
The rainfall recorded at the Royal Observatory for the 12 month period 1st August 1966 - 31st July 1967 was 43, 33 inches, compared with an average of 85, 39 inches. This is the lowest rainfall for the period ever recorded at the Royal Observatory. (The previous lowest in 1963/64 was 50.4 inches).
4
The storage position on 1st August was 5, 380 M. G. in all storage reservoirs excluding Plover Cove, with approximately a further 700 million gallons in Plover Cove above the -27 P. D. level - i. e. the level of the new temporary outlet point which is presently being installed. Although it is far from certain that water from Plover Cove can be used this winter and, all other difficulties aside, it will only be possible to use it if rather high salinities are accepted in the water supply, it is proposed to include the presently available and future storages of Plover Cove in the calculations of the water supply position.
5
If we continue on the present supply, the total consumption between 1st August 1967 and 1st July 1968 will be 20,700 M.G. (334 days @ 62 M. G. D). The resources at present are:
Plover Cove
Other Reservoirs
Total:
700 M. G. 5,380
6,080 M. G.
*
The yields which can be anticipated during a very dry winter roughly corresponding to the winter of 1963/64 are:
CONFIDENTIAL