CO129-328 - Governor Nathan - 1905 [1-6] — Page 315

Losure!

by Parcel

Plans,

Post I

310

dam for the low level reservoir in Tytan Tuk Bay which had

been commenced in 1902 were brought to a conclusion on the

10th. October, 1904, I annex a final report by Mr. P. N. H.

Jones, Acting Director of Public Works on these trials, ac- companied by a plan and section of the borings, etc. They show that of the two sites that have been suggested for the dam

and have been tested by well sinking and pricking that to

seaward

-

(No. 1), in spite of requiring the water-tight

diaphragm of the dam to be taken down to solid rock at a gene-

ral level of 65 feet instead of to one of from 45 to 54 feet

below Ordnance Datum, is the more advantageous as the dam

there would be little over three-quarters of the length of a

dam at No. 2 site and would impound a much larger quantity of

water.

4

With an overflow level 60 feet above

Ordnance Datum a dam on No. 1 site will impound approximately

1,200 million gallons. The catchment area of the reservoir

formed by this dam is 2,292 acres but the water falling on

690 acres out of this area is taken up by the old Tytan Reser-

voir while that falling on another 320 acres is already partial-

ly intercepted by catchwaters. The reservoir now proposed

will therefore take the complete drainage of 1,282 acres and

the partial drainage of 320 acres.

area

I enclose a report by Mr. D. Jaffe, Acting

Executive Engineer, on the relation between this drainage

and the impound of the proposed reservoir. It has been drawn

up on the data furnished by three years' low rainfall and on

certain assumptions as to the proportion of the rainfall

available for storage. It indicates that 1,200 million gallons

Conclosure 2. Chests Toss to 6

by Parcel Post

can,