Sunday 20 November 2016

Fourth Trip To Mudan Reservoir (牡丹水庫)

In front of the Mudan reservoir spillway, yesterday morning.
My plan for this weekend was to get an early night on Friday and leave the house in Tainan at 5am for the long drive south into deepest Pingtung county. I have been wanting to revisit Mudan reservoir for some time since my last trip in February 2013. I usually peg that as a three hour drive if I leave early and make good time, which means getting to the reservoir at about 8am can only be accomplished by leaving Tainan city at 5am at the latest. As it was, I ended up in bed at about midnight and awoke of my own accord at 5am, completely sleeping through my 4am and 4.30am alarms. That 5am waking time gave me a short window in which to walk the dogs, get some coffee down my neck and get out of the door as soon as possible, but it still meant driving past the Chi Mei museum on the edge of the city at 6.30am, which is quite late and meant a likely 9.30am arrival at Mudan reservoir.

Stitched panorama shot overlooking the reservoir from the north at some time after 9am.
I drove as fast as I could safely allow myself and, aided by the relatively sparse traffic, made it all the south way to Checheng village inside two hours. I had wanted to stop several times between Jiadong and Fangliao townships to photograph the spectacular early morning sunshine over the mountains, but I kept the discipline needed to make up as much time as I could after my late start. In some ways this is a regret. I stopped only at red lights and then the Hi-Life convenience store in Checheng for some coffee and a bite to eat before taking the always windswept 199 up to Shihmen village. Rather than go straight to the front of the reservoir, I took the back road up along the hillside shoulder only to find that, after a certain distance, it was being torn up by excavators in preparation for the surface to be relaid (this road has been in bad condition since I first drove on it in 2012). However, as I was preparing to turn around and leave, one of the truck drivers gestured to me that I could just drive over the broken road. I turned in surprise and the excavator driver used the head of his iron claw to pat down and flatten the broken shards of tarmac, concrete and dry earth so that I could drive across. I thanked them and found that their section of repair was only a few hundred meters in length, rounding only one corner after which I was returned to the same old cracked road I remembered from three or four years ago. That road leads to some spectacular views southward out across the reservoir toward the dam...

One of my favourite reservoir views in all Taiwan, though this shot isn't nearly as good as the ones I managed in 2012 and 2013.
I drove on with the purpose of revisiting the check dam which had been under repair and improvement back in February 2013. In the intervening years there had been significant growth in the trees and bushes along the hillside such that the same exact views were no longer available...

The now fully repaired and expanded check dam on the reservoir's northern feeder river.
The repair and expansion to this check dam included the new retaining walls on either side between the two weirs which are built from the same material and in the same way as the original baffling weir. The walls were necessary to prevent possible landslides into the stilling basin.
Another view over the check dam; all but one of the weir openings is still blocked up.
I drove down to the bottom of the hillside next to the river bed, which had previously been where the road ended and I had walked about aimlessly among the rocks. This time however, the road carried on upstream, albeit in the form of an unpaved dirt track. I left the motorbike and followed the road on foot with only my camera and 18mm lens and found that there was a second check dam a short distance upstream...

This second check dam is obviously similar to the first one in layout.
However, it differs in being built out of stacked gabion baskets rather than the brick-like appearance of dressed concrete. The same is true for the retaining walls on either side.
Although the main check dam and its retaining walls are built from stacked gabion baskets, the prefacing wall for the stilling basin is dressed concrete.
View upstream from the second check dam.
Looking back downstream at the second check dam; it is strewn with dead driftwood.
The muddy sediments deposited over the years; the purpose of the check dams is to slow the river and minimize the quantity of sediment to reach the reservoir itself.
Vast cakes of the stuff, just baking under the late morning sunshine.
Looking downstream across the silt-pans toward the second check dam.
I returned to the bike and drove back toward Shihmen village, but stopped briefly when I saw what I took to be snake tracks in the dust...

Can you correctly infer the length of a snake from the length of its' tracks? I'm not sure that you can, but if so then this track is about four meters long, which is not in any sense small. Perhaps this snake had been lying still and was suddenly disturbed making a quick, darting struggle to get out off the road, which might explain the lack of any other tracks on either side.
A parting shot south toward the dam.
Before leaving the hillside road, I decided to climb an old stone staircase adjacent to it, hoping to find a good view over the reservoir from a higher elevation. The stairs were steep, laid out in seven stories each separated by concrete rillways to discharge water and protect the soil. The staircase was also strewn with broken branches and young trees growing across it making the climb awkward at points. However, when I arrived at the end of the seventh story, there were simply no more stairs, even though the summit of the hill had not been reached. I turned around to see that I had wasted my sweat on achieving a view of nothing much in particular...

A waste of energy.
After leaving the hillside back road, I drove around to the front of the reservoir stopping to buy water at the little store. I parked my motorbike at the entrance leaving my lumberjack shirt and fleece jacket behind. Unlike at most other reservoirs in Taiwan, at Mudan reservoir vehicles are not permitted within the grounds and you have to walk to the dam. There is a little park where people sit and eat picnics with a view toward the dam and spillway...

Standing next to the stilling basin at the end of the spillway.
Erosion marks from leaking water underneath the spillway.
The stone staircase for the dam; it is steep, but the warning to people with cardiovascular disease is a symptom of a ridiculous tendency in Taiwan for public "authorities" to insure themselves against fatuous litigation by issuing public warnings or even outright prohibitions. This includes waterfalls and swimming holes, many of which are now off-limits to the public. This is the only case I know of featuring a staircase to a dam; at all other reservoirs, access to the dam crest is open to private vehicles except in those cases where there are blanket restrictions, as at Feitsui, Fongshan and Xinshan reservoirs.
Stitched panorama shot looking north over the reservoir from the approximate center of the dam crest.
I climbed back down the staircase to retake an old photograph I had spoiled with overexposure in 2012; I am still mystified as to the precise function of this tunnel as its' cul-de-sac ending means it cannot be a sluiceway, but the narrow aperture makes it seem unlikely as an access tunnel to any sort of gallery (and in any case, the dam is an earth-filled dam rather than concrete so it's unlikely to have a gallery).

What is this tunnel for?
Two pressurizing pumps serving to pipe water downstream to a treatment facility.
I am still mystified as to why Mudan reservoir's spillway, built in the 1990s was designed with tainter gates rather than the open overflow designs that became prevalent in Taiwan from the late 1970s down to today. Mudan reservoir is one of the few odd exceptions to a general trend that encompasses eight other spillways built since the late '70s...

The exception to the rule: Mudan's old fashioned radial tainter gate controlled spillway.
These dumper trucks were depositing the broken shards of tarmac and concrete from the hillside road at the front of the spillway's stilling basin, where they will eventually be washed away and returned to the ocean to form new sand particles for the beaches.
Telephoto shot of the dam from a shoulder of the 199 as it winds its' way uphill eastward. All dams should be photographed from exactly this kind of elevation and perspective - it is perfect.
The final view before the long, exhausting drive north back to Tainan city.

2 comments:

  1. A beautiful landscape!I understand why to talk about Mudan and my last post! You are a true connoisseur in dam it is incredible.I never thought that there was so many dams in Taiwan.Thanks to you I discover a new aspect of the island.

    ReplyDelete
  2. You're welcome! My interest in dams seems to bore most people to tears, but it keeps me occupied.

    ReplyDelete

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