Rice output may
be trebled in
Kedah, Perlis
WORTHERN
IRRIGATION
Malaya
AREA
PERLIS
CENTRAL
IRRIGATION
AREA
NORTHERN CANAL
Rock dams
for Pedu
and Muda
N
SOUTHERN
IRRIGATION-
AREA
PELUSTANG HEADWORKS
PROVINCE
WELLESLEY
Pouch Sana
CENTRAL CANAL
KEDAH
SIA
LEGEND
INTERNATIONAL BOUNDARY
STATE BOUNDARY
EXISTING ROADS
RAILWAYS
THAILAND
-
PIDU BASH
ACCESS ROADS
SAONG TUNNEL
- Catchment area
boundary
PERAK
5 4 3 2 10
P
being
made
REPARATIONS are to invite tenders for construction of the Muda River Project, which will provide a firm water supply for the irrigation and intensive cultiva- tion of about 400 square miles in the coastal plains of the States of Kedah and Perlis in Malaya.
The population of this area, estimated at 325,000, is mostly depen- dent for its livelihood on rice cul- tivation. It is believed that the pre- sent yield of rice from the area can be almost trebled and will even- tually amount to about 40 per cent. of the rice output of all the States of Malaya.
of
Sir William Halcrow & Partners, London, are the consulting engineers to the Ministry of Agriculture and Co-operatives, Government Malaysia, who are themselves design- ing the system of canals which dis- tributes water from the three main canals on to the padi.
to
The essence of the proposed scheme is to make good the spasmodic deficiencies of rainfall and run-off by the supply of water from storage reservoirs; thus provide sufficient water to meet the demand for cultivation of two crops even in very dry years. To achieve this, it is proposed that a large catchment area with a small poten- tial storage capacity on the Sungei
PENANG ISLAND
KWw
Muda should be united by a tunnel with a neighbouring small catchment area with a large potential storage capacity on the Sungei Pedu. The combined reservoir thus formed would store about 1 million acre feet, sufficient for an average firm supply of about 1,100 cusecs.
Discharge from the reservoirs via the natural river channels and canals to be constructed would feed а southern irrigation area of some 43,000 acres from Muda, and some 218,000 acres from Pedu. A plan of the scheme is shown above.
The main structures will be Pedu
dam, Muda dam, Saiong tunnel, embankments at Batang, Northern canal, Central canal and Southern canal, each with associated structures.
Integrated control
It is envisaged that good use will be made of the heavy annual rainfall and the uncontrolled stream flow reaching the cultivated areas from below the reservoirs, by an integrated system of control. The essence of this will be to maintain the mini- mum acceptable water levels on the padi fields during dry periods when the reservoir is discharging. This will leave room for rainfall and stream flow when available to be absorbed in raising the water level to the maximum acceptable for cultivation
Far East Architect & Builder January, 1965
before any surplus flows away to waste. Various operational systems have been tested by the consulting en- gineers to determine which would have been favourable over the 16 years for which river flow records are available. The calculations were processed by an 1.B.M. 7094 com- puter, which carried out more than 3 million numerical operations in less than an hour of machine time.
The availability of materials, foundation conditions and hence the cost have resulted in designs for rolled rock fill dams at both Pedu and Muda. The height of the dams will be about 215 and 120 ft. respectively.
Details of the Pedu dam on the next page show an upstream im- permeable membrane of concrete. It is however expected that in the event, asphalt will be the chosen material for this membrane.
Both dams are to be provided with side channel spillways for the dis- charge of floods, which may be of high intensity at Muda. The con- necting concrete lined tunnel between the two reservoirs will be about 5 miles long and 15 ft. in diameter, and will have an isolating gate at each end. For the intended reservoir water level, saddles on the watershed will have to be closed by embank- ments at Batang.
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