Wednesday 17 June 2015

A Belated Write Up: The Water Intake Structure For Hushan Reservoir (湖山水庫)

Five weeks ago, on Sunday May 10th, I took the train back up to Douliu city in Yunlin County in order to find the river weir and intake structure for the new reservoir. It was a dull, overcast day which broke out in occassional showers. The source river is the "Ching-shui" river (清水溪), which itself is a major tributary to Taiwan's largest river, the "Zhuo-shui" river. I already knew its' approximate location from having looked at various maps online and made my way through Gukeng district on the 158甲 before switching onto the 149甲 (it would have been quicker to take the 149甲 directly out of Douliu, but the 158甲 passes by the locally famous theme park "Jenfushan", which actually turned out to be not that impressive; just a ferris wheel and a decades-old small roller coaster). The road passes over a line of large foothills prefacing the central mountain range and which also form the county border with Nantou, thus placing the Ching-shui river valley in Nantou county. And here it is...

Looking south-south-west upstream along the Ching-shui river from a road bridge on the 149 toward the new weir and intake structure in the distance. It was a dank and miserable day weather-wise but entirely welcome given the recent drought.

The same view but taken with the 300mm focusing on the low, but very wide weir crest.

Standing on the footbridge over the river looking north downstream to the weir gates; the actual intake is to the left and consists of a massive grilled aperture between the 30-foot tall concrete ballustrades.

Another view from a better angle; it is the largest structure of this type I have seen during my many reservoir trips. Note the large disparity in height between the water intake mesh and the curved outer wall and weir crest to the right: in the event of flood waters on that scale, would the curved and low weir crest allow sufficient water to enter the intake tunnel? Flood control being an obvious function of the new reservoir and its' spillway and sluiceways.

The view southwards and upstream from the same footbridge opposite the new water intake; the sculpting of the river bed to direct most of the river's current toward the weir gates and the water intake is common practice. But note also the concrete walls on either side built to prevent erosion of the river banks just before the new intake structure.

From the other side of the river looking directly across the weir crest toward the weir gates and the water intake structure. The weir must be close to a hundred meters from one end to the other.

A sluiceway hatch downstream from the weir gates; presumably the tunnel behind this hatch connects to the water intake structure and exists in order to discharge excess water in the event of flooding.

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