CIVIL ENGINEERING AND PUBLIC WORKS
Jam and reservoir looking downstream. Irrigated area is shown in left background
stream of a tributory of the Chishui River. Its functions include irriga- ion, flood control, water supply and ecreation.
After extensive study, construction work commenced in July 1961 and was finished in the summer of 1965.
An earth dam with a maximum height of 42.5 metres has been con- structed to form an impounding re-
ervoir.
The embankment volume of the lam is 1,000,000 cubic metres and he gross storage capacity of the re- servoir is 21,600,000 cubic metres. The total construction cost was NT- $205 million, which was borne joint- y by the Taiwan Provincial Govern- ment and the beneficiaries.
Main features of the project in- clude:
1. Reservoir The artificial lake formed by the dam covers an area of about two square kilometers. From the storage capacity. 19,400,- 000 cubic metres of water will be available for irrigation and other pur-
poses.
2. Main dam The rolled earth- till dam measures 210 metres long at the top and has a crest width of 12 metres. A concrete cut-off wall and curtain grouting are provided under-
neath the central impervious core. An auxiliary dam is sited on the left of the main dam: this is also earth- filled and measures 8.5 metres high and 130 metres long at the top.
3. Spillway A reinforced con- crete chute type spillway is built on the mountain slope at the right side. of the main dam. Three 8 x 5.58 metre steel fabricated tainter gates are installed to discharge the flood
water.
4. Inlet tunnel and intake tower
For irrigation two intake towers with connecting tunnels, are located on each side of the dam.
The sup- ply tunnel is installed with two 1.5 x 2.2 metre high-pressure slide gates to drain the sediments flowing into the reservoir.
5. Irrigation system The irri- gation system, including main canals, laterals, sub-laterals and farm ditches makes up a total length of 93,800 metres. Measuring devices. check gates and distributing boxes are in- stalled and rotational irrigation and land
consolidation practices have been introduced thoughout the entire irrigated area.
The Paiho project, the third multi- purpose scheme in Taiwan, will bring tremendous benefits in rice production
Some 1,866 hectares of dry land will be converted into single-crop paddies. and 1,017 hectares of single-crop pad. dies will become two-crop paddies. In addition an area of 1.063 hectares of single-crop paddies will be improv- ed by supplementary water supply.
Altogether, water from the Paiho reservoir will serve 3,946 hectares of farmland, resulting in an estimated in- crease in rice output of 7.230 metric tons annually.
Completion of the reservoir will reduce the flood discharge of the Chishui River from 890 to 670 cubic metres per second, thus removing flood threats on low lying lands.
So far as domestic water supply is concerned, some 20.000 inhabitants at Paiho and Tungshan will get tap water supply for the first time and the supply to Hsinying and Yenshui will be increased.
Tourism may be a side benefit of the reservoir project. The site is near the scenic Kwantseling and the two may be developed as a single tourist
resort.
Design and construction of the Paiho project was supervised by the chief engineer of the Taiwan Provin- cial Water Conservancy Bureau, Mr. F. Y. Liu.
Newly irrigated paddy field with lined canals
Far East Architect & Builder January, 1966
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