Water Resources Planning Branch, WRA, MOEAWater Resources Planning Branch, WRA, MOEA

Baihe Reservoir is in the hilly area of southern Taiwan and is built on Baishui River(as shown in Figure 1). It was completed in 1965 for a multi-objective reservoir, including water supply, irrigation, flood control, and tourism. Agricultural irrigation is its main water supply target. Its capacity was 25 million cubic meters as completed in 1965. Present storage capacity is about 10 million cubic meters(i.e. 43% of the original capacity).

Due to serious siltation problem, Water Resources Planning Institute, Water Resources Agency, Ministry of Economic Affairs (WRPI) has done experiments about the sediment sluicing tunnel and provided experimental results for engineering design. After the completion of the sediment slucing tunnel, it can not only increase the amount of flood discharge by 287 m3/s, but also serve as the bottom outlet to eliminate the sediment. The Original case of Physical Model was built in 2013 as shown in Figure 2.

After serious experiments and modified design, the final plan view and profile of the tunnel are shown in Figure 3 & Figure 4. The sediment sluicing tunnel is under construction and will be finished in 2019.

Another tunnel is under planning for sediment bypass function. The intake of sediment bypass tunnel will be located on Baishui River, the upstream side of Baihe Reservoir in Figure 5 & Figure 6. In the storage period, a sediment bypass tunnel is necessary for sediment venting. This tunnel uses a five-year frequency flood as the design flow and the discharge is 200 m3/s. When floods occur, sediment will be bypassed from this tunnel to the downstream of the reservoir. The experiments of sediment bypass tunnel are executing and the results will provide for engineering design.