Q 64
of the Tytam Tuk East Catchwater and in order to minimise the silting up of this intake by spoil from the tunnel excavations, two silt traps have been formed by the construction of granite rubble walls across the stream bed. A penalty of $2,850.00 was imposed on the contractor for non-completion in extended contract time.
237. Pottinger Peak Catchwater :- Second Section. - A contract of $53,630.00 was signed with Messrs. Sang Lee & Co. on the 11th April, 1984. Fairly good progress was made and the works were completed by the end of the year. The works consist of the construction of three small catchwaters draining the slopes of Pottinger Peak and Mount Collinson.
The Pottinger Peak North Catchwater is 6,306 feet in length and drains an area of 103 acres of the Northern slopes of Pottinger Peak. The catchwater is constructed in three different sizes, the cross-sectional areas being 8.7, 5.7, and 3.0 square feet respectively.
The Pottinger Peak South Catchwater is 4,388 feet in length and drains an area of seventy acres of the south slopes of Pottinger Peak. The catchwater is constructed in three different sizes, the cross-sectional areas being 5.9, 4.2, and 2.0 square feet respectively.
The Mount Collinson East Catchwater is 2,970 feet in length and drains an area of fifty-eight acres of the east slopes of Mount Collinson. For the majority of its length, the catchwater has a cross-sectional area of 5.9 square feet, a length of 180 feet at the intake end having a sectional area of 2.0 square feet.
The two latter catchwaters discharge through Pottinger Gap into a common outfall leading to the junction of the Pottinger Peak North Catchwater and the First Section of the Pottinger Peak Catchwater referred to in paragraph 249 of last year's Report. The general construction of the catchwaters is similar to that of the Pottinger Peak Catchwater First Section. The two Pottinger Peak Catchwaters are designed for a run-off of 1/2" per hour and the Mount Collinson Catchwater 3.5" per hour, the maximum velocities of all being six feet per second.
238. Dragon's Back Catchwater :- First Section. - This work was referred to in paragraph 250 of last year's Report. Progress on the remaining portion of the work was slow owing to the rocky nature of the ground. The works were completed on 5th March, 1934. The catchwater drains an area of 170 acres on the western slopes of Mount Collinson and the Dragon's Back Ridge and has a total length of 8,259 feet. It is designed to take a run-off of " per hour together with the discharge