presence of pocooles intermixed with a red and white substance of a gravelly and rather chalky nature would lead to the inference that it consists of what nearly the whole of the Island of Hong Kong is formed, namely of Granite in a state of decomposition, the clay being probably formed by the decomposition of the Felspar in the granite. It will be impossible to make a thorough inspection of the bed of the reservoir till after the Trials, the test holes that have been sunk are 10 feet in depth only.
The proposed Embankment will be laid on a bed of Concrete and will be formed of material from the inside bed of the Reservoir carried by coolies in baskets and rammed in 12 inch layers. The puddle wall will be formed of Canton river mud, a most excellent material for the purpose, it will be protected by decomposed Granite and Lime also rammed in layers. The up side and top of the Embankment will be faced with Granite in 12 inch courses laid in Cement, and pointed with oil Putty.
A Valve well will be constructed on the South East side of the Embankment and 25 feet above the Bed of the Reservoir, within this place Valves will be placed to draw off the water at different levels, a Culvert will communicate between the valve well and the Gauge Basin, and in this culvert 10 pipes will be laid to draw off by a syphon arrangement the lower 25 feet of water from the Reservoir. The Valve well and Culvert will enable the valves and Syphon to be always within reach of examination and repairs.
Perhaps the most important portion of this work is the means for safely passing off flood waters. Annual rainfall during the last seven years, the year 1860 excepted, will be found from the accompanying statement to be 84 inches. The area of the gathering ground is 330 acres and the Reservoir Area will probably be about 30 acres. I propose to construct the Bye Wash as shown on the plan 50 feet wide and calculate that it will discharge 11,016,000 cubic feet of water or a rain fall on the Gathering Ground of nearly 6 inches per hour; it would appear to be impossible that such a rain fall as 6 inches per hour could ever fall, there has however been a depth of 2.6 inches of water over the existing weir which is 120 feet wide, and simply give a water way of 400 square feet in place of 300 square feet which has virtually been found to be required. A Culvert under the Bye Wash is provided for use in case of emergency, this with the sluice valves in the Valve Well will discharge a further 2,091,000 cubic feet per hour.
During the Construction of the Embankment a temporary Bye Wash must be formed to carry off flood water and the nature of the ground will necessitate its being placed where the permanent Bye Wash will be formed, but of course at a lower level probably 15 feet above the Bed of the Reservoir or at the Level at which it is proposed to construct the main Culvert. I should hope to be able to complete the Embankment to...
presence of pocooles intermixed with a red and While pubstance of a gravelly and rather chaltly nature would lead to the inference that-it- Consists of what nearly the whole of the Soland of Hong Kong is formed, namely of Granite in a state of decomposition, the clay being probably forrned by the decomposition of the Helspar in the franite. It will be impovosible to marke a thorough inspection of the bed of the reservoir till after the Trains, the treat holes that have been Sunt are 10 feel indepth only.
1
The proposed Embantement-critl be laid on a The Embankme
"Concrete and will be formed of material from the inside
Bed
läkten
of
of
the Reservoir carried by coolies in baotlets and rammed in 12 erich layers. The youddle wall will be formed of Canton river mud, a most-excellent onaterial for the yourjoove, it will be pourected by decom- "Jorved Granite and Lime alor rammed in Layers. The up side and top of the Embanthment- will be faced with Granite in 12 in: courser laid in Cement, and pointed with oil Putty.
grell
polid ground
A Valve well will be constructed on, on the South East ;oide of the Embantiment-and 25 feet above the Bed of the Reservoir, within this u pluice Valves will be placed to draw of the water at different levels, a Culvert-573 will Communicati between the valve well and the Gauge Bavin, and in this culvert 10 "pipes will be laid to draw off-
by a pyjohon arrangement the lower 25 feet Syphon of water from the Reservoir The Valve orell and Aubert- will enable the valves and Syphore to be always
within reach of examination and refocirs.
400
Bye Wash Perhaps the most important poortion of this work is the means for safely passing off flood maters. Annual pain fall during the last-
average
The
Seven
years,
the year 1800 excepted will be found from the accompanying statement to be st inches - The
of the gathering ground is 330 acres and the Reservoir Area will probably be about:
area
Sacred
F propose to construct the Bye rash as shown on the plan 50 = " " x 5th and calculate that it mill discharge 11,016.000 Cft of water or apain fall on the Gathering Ground of Nearly to in per hour; it would appear to be impossible that such as rain fall
as 6 in : your hour could ever fall, there has however been a depth
a depth of 2.6" of water over the existing weir orhich is 120 feet ride, and Jsimply give a mater way of 400 &quare feet-
in place of 300 square feet which has victually been found to be required. A Culvert under the Byelvash is provided for ure in care
gemergency,
Q
this with the sluice valves in the Valve Well will discharge a further 2.
further 2.091, boo c. ft Joerhour. During the Construction of the Embankment -
temporary 18ye Wash must be formed to carry off flood water and the nature of the ground mll necervilate its being placed notere the four- manent Bye Wash will be formed, but of course at a lower level probably 15-feet-above the Bed of the Reservoir or at the Level at which it is proposed to construct the maste Culvert; Should hope to be able to complete the Embankment to
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