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consisted merely of a cutting in the hillside of the width stated, with the necessary cross drains where required.
The construction of the reservoir also entailed raising the level of the main road to Sha Tin and Tai Po for a distance of nearly half a mile to an average extent of 1 foot 6 inches.
(ii.) Caretaker's Bungalow.---This is built on a site within 100 feet of the Tai Po Road, where it commands a view of both the main and overflow dams of the storage reservoir. The main building contains 5 rooms, 2 bathrooms and verandahs and is designed to accommodate a caretaker and any officer whose duty may require him to reside temporarily in the locality. Suitable servants' quarters are also provided. With the exception of a stone base, 4 feet high, the walls are of Canton brick in lime mortar, faced with Amoy bricks. The floors of the rooms are of teakwood on hardwood joists and the floors of verandahs of cement tiles on cement concrete.
(iii.) Catchwaters.---The natural catchment area of the reservoir, as already mentioned, is only 438 acres, the yield from which would be insufficient to fill a reservoir of such capacity in years of low rainfall and it was therefore necessary to supplement it by means of catchwaters. The main catchwater commences near the East end of the reservoir. Passing under the Tai Po Road it is carried for a distance of 2 miles along the Northern slopes of the Kowloon range of hills, terminating at the stream which flows Northward from the Lion's Head or Kowloon Pass. It intercepts the water from an area of 400 acres and, except where crossing stream-courses, is cut entirely out of the solid. Commencing with a cutting in solid rock through a gap in the hills, it has an average width of 21 feet and depth of 7′ 6′′, diminishing gradually to 15 feet by 8 feet at its upper end. A small V-shaped channel is formed at one side to carry the dry weather flow; sand pits, extending the full width of the channel, are constructed at intervals of 200 feet to intercept any grit that may be carried by the water during rainstorms and overflows are provided at most of the points where any considerable streams enter the catchwater. A path, 6 feet wide, has been constructed on the outer bank of the catchwater and is carried across the overflows by concrete bridges. The bottom of the channel is lined with cement concrete 4" thick and the sides with lime concrete of the same thickness. The catchwater has a fall of 1 in 2,400 and when running full it is calculated that it will carry 20 million gallons an hour. This capacity was provided so that it may in future be extended to intercept the water from a further area of 600 acres, or 1,000 acres in all, and it is designed to carry a rainfall of 1" per hour from the last-mentioned area. A clockwork recorder has been provided to register the depth of the water flowing in the catchwater.
The second catchwater, which is 500 feet long, with a sectional area of 7 square feet, intercepts a stream with a drainage area of 28 acres near the Caretaker's Bungalow and discharges into the Reservoir at the Byewash Dam.
(iv.) Clearwater Channel.-To avoid drawing water from the Reservoir when, after heavy rains, it may be too turbid to be easily