Two Weekend Trips: The Tseng-wen Reservoir Trans-Basin Diversion Tunnel

For my first act this weekend, I drove out to the back of Tseng-wen reservoir on Saturday to photograph the trans-basin diversion tunnel exit point, which lies at the head of the tributary stream I had followed last weekend. This time however, I took a detour from the reservoir onto a road I had never previously followed - the Chiayi 147. This road, as I had checked on google earth, takes you directly to the head of the stream where the diversion tunnel ends.

When I arrived at Tseng-wen reservoir I initially took two wrong roads by relying on an insufficiently detailed memory of what the correct turn-off looked like (all three have similar features). I ended up in farmers' cul-de-sacs before finding a place that combined sufficient reception and sufficient shade to allow me to consult with google earth again to re-check my position relative to the correct turn-off point. While I was there, I accidentally disturbed an eagle by the roadside. She took off and found an alternative perch some distance away...

Despite several other relatively close encounters today, this was the best shot I managed to take.

Eventually I arrived at the correct turn off for the 147, which was in fact signposted, and drove past the few dotted little houses and up onto the climb. A note on that road: the first half of it - from the highway 3 turn-off until a few kilometers before the crest of the ridge - is a joy to drive; its' asphalt surface is smooth and has been very well maintained, there is almost no other traffic on it whatsoever and it runs parallel to a narrow stream gorge surrounded by bits of broken cliff with the odd dead tree sticking out among the intense foliage (perfect for eagles to perch in whilst keeping an eye out for snakes and lizards). Just before the crest of the ridge however, it becomes a nightmare of a broken up stone and gravel interspersed with patches of cracked and rock-studded cement. It is like that from the crest onward and downhill all the way into the valley on the other side. I didn't get beyond 2nd gear and was in 1st or neutral most of the time.

The eventual view down into the valley - the diversion tunnel is visible off to the right of the image...

The site as a whole is still far from complete. The embankments for the stream are still unfinished, there are culvert pipes lying around and a makeshift bridge is still in use for now...

The tunnel mouth itself, with various machines parked outside...

Another shot of the tunnel mouth showing the tunnel bore machine just outside...

The same view with additional context below. Notice the concrete bunker-like structure below; there are in fact two structures - that one, and another immediately behind the TBM and fenced off with railing. I suspect that one of these will function as the penstock of water to be measured and released into the existing stream bed and the other will function as flood-control device via an underground culvert leading to a second stream bed off camera to the left.

This shot below shows what I mean. There is a natural confluence of two stream beds here; the one to the right will be fed by the diversion tunnel, whilst the one to the left will be used for flood control so as to prevent erosion damage to the first stream bed...

The public information sign for the project put up by the Water Bureau. The scheduled date of completion has been pushed back at least once (with the numbers edited rather than the whole sign replaced). The current due date for completion is 30th June this year...

The perspective drawing illustrates the two-part nature of the tunnel; the longer, eastern tunnel removes water from the Laonung river in the east of Kaohsiung and diverts it west-north-west underground to the shorter, western tunnel which exits here...

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For my second act, I drove out on Sunday to try (once again) to locate the entrance to the eastern half of the trans-basin diversion tunnel on the Laonung river up in Kaohsiung county. From what I had read, the tunnel begins at a weir named after the small village of "Chinghe" which it is (apparently) sited by, just north of Taoyuan village. On two recent trips to this very same area however, I failed to find anything resembling a weir and entrapment pen for a diversion tunnel. After reading up a bit more on the tunnel, I wondered whether I had missed something.

I stopped briefly on the Jiaxian bridge to take a look at the Jiaxian weir, which serves as the entrance for the Nanhua reservoir diversion channel...

Below: a bare cliff-face being given remedial anti-erosion treatment; the same thing was done at "the Big Cliff" to the north of Taoyuan village and that has since collapsed as I discovered a few weeks back.

The new dike just outside Taoyuan village. I had suspected that I had missed something here previously, but no. Not only did I photograph the area from across the river, but I actually entered the building site to have a closer look - there really isn't anything resembling a weir or a diversion tunnel there at all. This left me in a state of confusion as to where the weir could possibly be.

I tried the next village ("Chinghe" after which the weir is named) in case I had missed something else there, but found nothing. I was looking across the river from the east side (on which Chinghe village is located) toward the west, but just as on my trips a few weeks ago, I couldn't see a thing even remotely resembling what I was looking out for. I then asked some locals at a shop, and they told me there wasn't any such weir. But then another guy said that there was a weir and that it was near the village. So I decided to head back to Taoyuan and drive up the mountain which overlooks Chinghe village and the river bed to see if I could see something I had been missing. I kept thinking this was stupid though because logically, the tunnel must be located on the west side of the river, not the east side. Here's the view looking down to Chinghe - nothing there, other than the anti-erosion work on the tributary...

Another shot looking upstream - the river is over on the western side of the river bed, but there is an obvious lack of visible infrastructure from that here all the way up to the next bend in the river...

I cannot believe it. Either the documents and public information about the tunnel is incorrect or misleading, or there is something there somewhere. One possibility that does occur to me is excavation; perhaps the tunnel is underground here on the east side somewhere, with the weir and entrapment pen which feeds it lying far further north upstream. But for now, I am stumped. I didn't have time to go and investigate further because it was already four o' clock, the light was fading and the dogs needed feeding and taking out to the park back home in Tainan city...

A disappointing day overall, and the best picture I managed all day was probably this one on the way back home going through Gaozhong village...