Saturday, 11 March 2017

Last weekend trip to Nanhua Reservoir to observe the construction work on the new sluiceway...

Downstream from Nanhua reservoir; the riverbed is split into sections by small dams designed to slow down the flow rate in order to alleviate soil erosion further downstream from fast-flowing discharge waters. To the left you can also see a series of silt traps downstream from the exit point for the new sluiceway tunnel.
That sluiceway tunnel exit mouth. Once the tunnel is completed, a channel will be dug to direct the water into the silt traps before entering the main course of the river downstream from the spillway.
The spillway; it has a discharge capacity of 4,332 cubic meters per second all of which is entirely uncontrolled due to the open overflow design of the lip-shaped sill.
The dam; 4,991,000 cubic meters in volume; which is fairly large for Taiwan.
Looking over to the higher of two adit points giving construction access to the new sluiceway tunnel.
The lower adit point with the twin-boom Fairchild C-119 in the background.
Profile of the sluiceway exit mouth from up on the hillside.
The additional, short dams downstream from the spillway's stilling basin. They double as silt traps in their own right but their primary function is to slow down the flow of water when the spillway is in operation.
The silt traps for the sluiceway.
Artificial wharf at the reservoir's southern end. This platform is used for loading equipment onto barges so that they can be sent northward (left) to the construction site at the upstream mouth of the new sluiceway. The reservoir is approximately half-full at the moment, and you can see from this image that there is a distance of about eight to ten meters between the water and the bridge. When the reservoir is full with the spillway in operation, this bridge is entirely submerged.
The construction site for the upstream point of the new sluiceway. If I am correct, then the tunnel mouth you can see is actually another adit point to allow workers' access to the sluiceway via a gallery, not the actual mouth of the sluiceway itself, which should be situated at a somewhat lower elevation.
Looking out northward over the management center from the public viewing platform with the curved arch dam in the background.

Wednesday, 8 March 2017

First YouTube Video

My friend Nathan Novak and I are starting up our own part-time video series talking about various topics related to Taiwan. Hopefully, this is the first of many videos to come, though as this is our first one there are problems with the video and audio quality which we'll get sorted out as we go on. Also, in watching it back again I cringe when I realize I used the word "county" instead of "district" when referring to the areas around Agongdian reservoir. Arggh! And my girlfriend says the laptop is too low and should be raised higher so I can look into the camera. Lots of little details to improve for the next one...

Friday, 3 March 2017

Juan Browne's Reporting Work At Oroville Reservoir

I've been following his videos from the beginning of the Oroville crisis and he has been doing splendid work reporting on what is actually happening, where other folks have been sat at home doom-mongering and speculating about what might happen. The words "reality check" are particularly apt to describe this man's work.

Wednesday, 1 March 2017

A Quick Response To Michael Turton's Article On Water Policy Published In Taiwan News, February 10th

On February 10th, earlier this month, Taiwan News published an opinion piece by Michael Turton on water policy in Taiwan. It contains numerous factual errors and distortions and several dubious claims but rather than list every single one of these, I'll just look at four of them. There are three points I want to look at first which concern factual errors or distortions and a final point I want to discuss at slightly greater length concerning a difference of opinion.

1. Reservoirs and sedimentation.

The first of these is a claim that you can often see made in Taiwan's media concerning Taiwan's reservoirs, which is that precipitation from typhoons causes landslides high up in the mountains resulting in large sediment volumes drifting downstream into the reservoirs. This does happen and as Turton rightly points out, this sedimentation process reduces the capacity of a reservoir and requires a very expensive clean up operation. Here is Turton in his own words...
"An Academia Sinica analysis showed that the incidence of severe and extremely severe precipitation has increased 100% in just 45 years, much higher than the global average. By making extreme weather events more severe, it increases the silt flows into Taiwan's reservoirs, reducing their capacity and necessitating costly silt removal programs, like the NT$16 billion program to clean up Tsengwen and Nanhua Reservoirs after Typhoon Morakot."
However, in making this claim in the generic - by referring to Taiwan's reservoirs in general - Turton neglects to mention a crucial fact: most of Taiwan's reservoirs do not actually suffer from this problem. Shihmen reservoir in Taoyuan certainly has this problem as do Tseng-wen, Nanhua and Baihe reservoirs in Chiayi and Tainan, and there are considerable sedimentation problems along Taiwan's longest river - the Zhuoshui river - starting high up in the mountains of Nantou, including Wan-Da reservoir, the bend in the river at Wuchieh and the barrage downstream at Jiji. So that amounts to five reservoirs with sedimentation problems, and seven if you loosen the definition of "reservoir" to include those two areas of the Zhuoshui river behind dams at Wuchieh and Jiji.

Taiwan's other reservoirs do not suffer from sedimentation problems either because of design, peculiar river topography or strict watershed management (or a certain combination thereof). Sixteen of Taiwan's reservoirs were actually designed "off-stream" so that water inflow can be shut off in the event of catastrophic rainfall. These are Xinshan, Baoshan I, Baoshan II, Yongheshan, Liyutan, Minghu, Mingtan, Sun Moon Lake, Hushan, Renyitan, Lantan, Wushantou, Agongdian, Fongshan, Cheng-Ching and Longxi reservoirs. A further seven reservoirs avoid this problem owing to some combination of strict watershed management (e.g. Feitsui reservoir) and peculiar topographical features that limit the inflow of water. These are Feitsui, Dapu, Mingde, Deiji, Guguan, Tianlun and Mudan reservoirs. A further nine reservoirs are comparatively much smaller and so much so that they are either rain-filled rather than fed by rivers, or their feeder rivers are so small as to not be able to carry much sediment in the first place. These are Xishe, Neipuzih, Luliao, Jianshanpi, Yenshuipi, Hutoupi, Manzhihmanpi, Jingmian and Longluantan reservoirs.

The reason I know this is because I have personally visited each and every one of the reservoirs on the main island of Taiwan with only two exceptions (the remote Longxi and Guguan reservoirs).

2. Funding, maintenance and administration of Feitsui reservoir.

The second point on which Turton is wrong concerns his claim that central government policies are biased toward Taipei city at the expense of other areas of Taiwan. I do not dispute the claim itself, but the example he uses to illustrate it. He writes that Feitsui reservoir's maintenance operations are funded by the central government and insinuates that this is unusual because Feitsui reservoir is the major reservoir which supplies water to Taipei city. Here is Turton in his own words...
"The cost of maintaining Feitsui Reservoir, which supplies the capital, is paid for by the central government, not the city, one of the many ways Taipei continues to be a colonial capital that maintains its lifestyle by draining resources from elsewhere in Taiwan."
The problem with this claim is that the maintenance costs of Taiwan's other major reservoirs are also borne by the central government. There are two relevant agencies here; the first is the Taipei Feitsui Reservoir Administration, which is funded by the central government, and the second is the Water Resources Agency, which is split into three regional offices - the Northern, Central and Southern Taiwan Water Resources Offices and all three of these offices are funded by the central government too. These three offices of the Water Resources Agency are responsible for the maintenance and upkeep of all major water-related infrastructure in their respective regions and this includes the major dams and reservoirs as well as major rivers and their flood-prevention levees, coastal erosion defenses and large underground aquifers. Taiwan's various local municipalities also have their own water resources bureaus but these offices are responsible for smaller-scale infrastructure such as minor rivers, ponds and smaller reservoirs, underground sewage systems and flood prevention mechanisms.

Now if I wanted to draw the same point, what I would point out would be the priority of funding to Taipei's Feitsui Reservoir Administration and contrast it to the long-delayed construction of the new sluiceway at Baihe reservoir down south here in Tainan. For those who don't know, Baihe reservoir is a major reservoir built during the 1950s to provide water for irrigation for sugar and rice fields in the areas in northern Tainan east of the Chianan canal. It also provided water for industrial paper mills and for the residential areas of Baihe, Dongshan and Xinying which was once the county capital. However, the reservoir and dam contained two serious design flaws that are only now being corrected with remedial engineering, and this is because maintenance of the reservoir had been kept at a bare minimum for decades as a result of budgetary constraints upon the Southern Region Water Resources Office.

3. The problem of land subsidence and the insinuation of water hording

The third point on which Turton is incorrect occurs when he writes about the problem of land subsidence. Again for those who don't know, there are certain areas of three counties in central and southern Taiwan that suffer from relatively severe forms of land subsidence, and these are the western areas of Changhua county, Yunlin county and one particular northwestern stretch of Pingtung county in Jiadong township. For a number of reasons the local farmers often pump out groundwater from underground aquifers for use in irrigating their fields and local people also rely on pumped groundwater for their own residential use. The combined overuse of groundwater creates air-filled cavities underground which cannot support the soil above and eventually collapse, which is what we call land subsidence. Turton correctly points out that when rice paddies are flooded through irrigation, the process is extremely inefficient with most of the water seeping through the soil and replenishing the underground aquifers. On this basis he then claims that not releasing agricultural water in order to save water is a false economy, since most of the water would go to replenishing underground aquifers. Here is what Turton says about it...
"It will then have to implement concrete changes in the government's administration of water, putting a halt to industrial use of groundwater, making sure that rice fields are regularly flooded to enable water to percolate back to groundwater reservoirs to curb subsidence (not releasing agricultural water to "save" water is a false economy), and investing in new pipes, treatment plants, and other facilities."
This is wrong on several grounds. First, saving water does not mean transferring water from one place to another, rather it means using less water. The problem in these areas is that the incentives for local farmers and local residents are skewed toward pumping groundwater at little to no cost to themselves and with no mechanism for assigning individual responsibility for the resulting land subsidence. It is a classic "tragedy of the commons" scenario. Secondly, it is not clear how "agricultural water" is "not being released". Neither of the three areas with land subsidence problems - western Changhua county, Yunlin county and Jiadong township in Pingtung county are served by reservoirs that can hold water back (though I must include the caveat that Yunlin county contains Taiwan's newest reservoir just completed but it is not scheduled to commence operation until the end of this year). So presumably what he means by water "not being released" is water contained in the local irrigation canals and controlled by the irrigation associations. Yet the irrigation systems in these areas are fed entirely by local rivers (Yunlin's very substantial irrigation system being fed by two large intakes on the Zhuoshui river), and so the water either enters the irrigation canal or is lost to the sea. The canals themselves do contain a series of locks and gates to control the flow of water, but their function is not to conserve water but to control the volumes of flow and prevent damage to the smaller, subordinate water channels and dikes. So Turton misleadingly writes as if water is being deliberately withheld either in reservoirs or in irrigation canals, but neither scenario is true. There are no reservoirs in these regions and the only purpose of the gates in the irrigation canals is to make sure you don't destroy your water channels, not to conserve water and prevent rice paddies from being "flooded".

4. Water Prices

The fourth point on which I take issue with Turton concerns his claims about water prices. Here we are not dealing with a factual error or distortion as such, we are dealing with a difference in opinion. He insists that water prices in Taiwan are so low as to encourage the wasteful use of water and should be raised considerably in order to prevent water shortages during times of drought. It is, on the face of it, a reasonable opinion. The implication he draws from this is that the government (or rather the Taiwan Water Corporation and Taipei Water Department more specifically) should begin to raise water prices. This is Turton in his own words...
"Water in Taiwan is strongly mispriced. When Chen Shui-bian came to power, he vowed not to raise water prices, even though at that time water in Taiwan was cheaper than in Malawi. Such policies have been followed by subsequent administrations, and Taiwan's water prices remain at about one-fifth of the global average."
And here...
"With such low prices, it is inevitable that Taipei once experienced frequent water shortages. As any economist will say, when the price of something is lower than it should be, demand will be unreasonably high." 
My difference of opinion with Turton here arises over those two words "should be"; what should the price of water be, and how should that price be determined? This boils down to a difference in political premises. Turton is arguing for government control of prices, whereas I believe prices can only be efficiently calculated in a free market. Another way of putting this is to say that Turton thinks that there are "correct" prices that can be determined relative to at least two political ends - one is allowing consumers as much water as possible and the other is preventing water shortages. The task is to discover what the "correct" or most efficient price should be that allows you to maximize both of these values. I, on the other hand, think that prices ought to be variable and set on the open market.

The problems with Turton's advocacy of continued government control of water prices are several, and it puts him in the rather odd position of arguing that water shortages have occurred due to government control of water prices and that nevertheless the solution is still government control of water prices!

One of the most obvious problems is that consumers differ in price sensitivity, so more price sensitive consumers (e.g. lower income people and industries that require large volumes of water for cooling purposes) are more likely to curb their water use at lower rises than less price sensitive consumers (e.g. higher income people and industries that use relatively little water). To address this problem he needs the Taiwan Water Corporation to charge different rates to different users, so high-volume users would have to pay more per liter of water than low volume users and perhaps people on higher incomes would have to pay more per liter of water than people on lower incomes. This does not really solve the problem however, as there are likely differences in price sensitivity within those groups and not just across them as well as differences in price sensitivity over time. And because the Water Corporation must get its' data from consultations with various different consumer groups rather than prices reflecting changes in supply and demand, it cannot therefore have sufficient data to accurately calculate and recalculate again and again what the various prices should be in order to get the most efficient use of water.

A second problem with this top-down, centralized approach to managing prices is that it ignores the possibility of water transfers and thus variable quantities of water to be consumed. Instead there is the assumption that the supply of water for industry, agriculture and residential use is fixed at certain, set quantities for a definite period of time and prices are then calculated as to how to best avoid shortages given these fixed quantities of water. But what if it were possible for one of several privatized water companies serving residential areas to act on behalf of its customers and bid for additional water from industrial or agricultural users? And vice versa - you could have industrial users bidding for additional water from privatized residential water companies. In this kind of situation, the quantity of water from which prices are to be calculated is not fixed but potentially variable, and the water economist David Zetland has written extensively about what he calls auction markets in water as the most efficient means of allocating water resources and avoiding the shortages that come from inefficient use. A good off-hand way to think about this is to consider agricultural goods that require large volumes of water to grow such as rice and then compare the price of those goods with the price residential water consumers would pay to be able to take a shower during water shortages. What would you prefer - more expensive rice, but the ability to take a shower - or cheap rice but the inability to take a shower?

Turton is right that water shortages are driven by public policy, but it is because public policy remains fixed on the premise of top-down management and fixing of prices by a State-owned utility that prevents a market emerging that would allow for more efficient transfers of water resources between different consumers at different times.

Monday, 27 February 2017

Baihe Reservoir: Pump Slope & Eagles

Somehow I dragged myself out of bed early this morning and, after the usual necessities, drove back up to Baihe reservoir near the border with Chiayi county this time with the intent of heading over to the reservoir's northern side and getting a look at what has been happening in an obscured cul-de-sac north-east from the dam's northern point where the new sluiceway is being constructed. The weather was not as bright as it had been yesterday with the sun partially obscured by a dense layer of grey cloud all morning, and although the air was also somewhat dank and humid, the strong winds which had been a nuisance yesterday had now dissipated. That made the weather good for driving, but not so good for photography...

Although I saw a lot more birds today than yesterday, they remained for the most part far out of the range of my 300mm lens. There were only two exceptions and this was moment - captured from about fifteen meters away, was one of them.
I had hoped to close the distance some more, but this Crested Serpent Eagle had other ideas.

This was what I had came to see; on the other side of that slope is the northern end of the Baihe dam and the construction site for the new sluiceway. I had wondered what exactly the engineers had been doing down in this corner and now I know; they set up a pump and generator with a pipeline over to the other side to pump water out of the reservoir to continue feeding the irrigation outlet as the normal passageways are (presumably) blocked up by sediments.
Close up shot with the black pipe draped over the side of the pontoon whilst held in place by a cable on a winch. The green boxes in the background are the generators and the black drum will probably be diesel. What the rusted metal float is for to the right of the pipeline's pontoon I am not sure.
The problem: the sediments from the Baihe river have now extended so far that the entire corridor between the north-west and south-west of the reservoir is clogged up and blocked; water no longer flows freely between the two areas. Four years ago I took a boat through here, but that is no longer possible now. After the new sluiceway is eventually completed, all of this sediment will have to be excavated and removed from the reservoir.
This is what happens; the sediment build up continues for so long that plants begin to grow on top of it, making it a permanent feature.
Looking back into the as yet unspoiled northern section of Baihe reservoir. If no attempt had been made to arrest the sedimentation creep, then in another five or six years this area would start to turn into a muddy swamp too.
The other exception to my attempt to photograph the raptors; I caught this eagle just as I was rounding my last bend in the reservoir to go home. He's perched in the tree eating what I think is either a lizard or a snake (zooming in close, you can get some idea but the resolution becomes poor).
I tried to close the distance a bit more, but this was as close as he'd let me get. He flew into a denser nearby tree where I could no longer see him. Shooting from the boat is very difficult.

Sunday, 26 February 2017

Sunday Afternoon With The Birds At Baihe Reservoir (白河水庫)

Arrival at the mid-point of the reservoir's southern shore at about 2.25pm; most of this area would be submerged during the summer but the water has now receded, not simply due to the lower precipitation in the winter but because of the ongoing draw-down for the construction of the new sluiceway.
My favourite shot of the day; for years I've been waiting to get a shot as good as this of an Osprey; they are the most difficult birds of prey to photograph in and around Taiwan's reservoirs.
A breeding pair of Black Kites attack a Crested Serpent Eagle. Guess why?
The middle half of the reservoir's southern arm - to the right (west), the reservoir becomes a de-facto swamp flooded with reed-beds, and to the left the eastern half of the reservoir remains relatively unperturbed.
I believe these are Sandpipers; they are actually standing on the mud just below the reservoir's surface; as you go further westward, the reservoir's depth continually shrinks until it is less than an inch deep.
The Black Kites mentioned earlier have a nest, which raises the question of whether the Eagle was hanging around in order to poach the chicks. An unattended chick would be easy meat for a Crested Serpent Eagle, which is about 50% larger than an adult Kite. With the reservoir's water levels now very low, there may be fewer fish to catch.

Fewer fish to catch would certainly be a problem for the Ospreys, who are now in competition with the Egrets along the reservoir's shorelines.

Another well-decent Osprey shot taken from my boat.
And another.
Papa Kite on patrol once more; the proximity of the Ospreys to the Kite's nest has not gone unnoticed.
The Ospreys are my favourite birds, partly because they are usually so difficult to photograph. Today was an exception.
Papa Kite begins to chase off one of the two Ospreys, though nowhere near as aggressively as he had attacked the eagle earlier on.
The Osprey is wary of the Kite and banks to avoid him.
After some time circling and chasing the Kite eventually left the Ospreys alone and did not attack them, though whether this was due to fatigue or some altered perception of the potential threat they posed I don't know.
The mid-point on the southern shoreline as I was leaving at about 4.30pm. This section of the reservoir is almost completely separated from both the western, eastern and norther sections of the reservoir. That is partly down to geography, partly due to the swamp-like disaster at the west end, and partly due to the very low level of the water. 
The dam crest has recently been excavated for repair; there is a new wall of fresh concrete on the upstream side and a new road will be laid along the top of the crest.
That corner of the southwestern end of the reservoir connects to the northern section and it was once possible to take a boat through there. Now excavators are driving through presumably to work on clearing out the massive sediment deposits that stretch out from the southwest and into the northern section some hundred meters or so.
The new wall along the dam crest as seen from the upstream side.
Closing panorama shot over the southwestern section of the reservoir; or what is left of it. There is an enormous amount of work to be done here in excavating all the excess sediment that underpins the reed-beds, and I can remember saying that this needed to be done about six years ago. Better late than never.

Wednesday, 15 February 2017

Reaction To The Oroville Spillway Damage In California

Three immediate thoughts on the Oroville spillway damage:

1) The main spillway is too narrow with insufficient discharge capacity. That would explain the damage to the concrete channel halfway down - the force of the discharge was too great to be supported by the channel walls.

2) The emergency spillway does not appear to have any channeling structure whatsoever to lead discharged water back to the river. So aside from the erosion of the concrete overflow lip itself, that would seem to be a cardinal design error.

3) If, as reported, there is a risk of flooding to the urban areas downstream, then the river leaving the reservoir has insufficient carrying capacity and should have been widened or supplemented with diversion channels.

(Further thoughts added later)...

4) Where is the stilling basin at the end of the main spillway channel?

5) Did the engineers err in calculating the maximum possible inflow of water into the reservoir from its' feeder river? If so, that is a catastrophic error that would not only have meant an inadequately sized main spillway, but may also mean that the dam itself will eventually prove inadequate to the sheer stresses it is currently being put under.

6) The apparent lack of any sort of channel for the emergency open overflow spillway really is astonishing, and this is made more so by the fact that the mountainside below it actually supports a number of pylons to carry power lines. Erosion of the mountainside from that emergency spillway will almost certainly mean that the pylons will fall and the power lines collapse. More importantly, if that emergency spillway collapses, along with the mountainside beneath it, then there is going to be catastrophic flooding downstream.

The design flaws here are of the order of criminal negligence, and it is astonishing that remedial measures were not taken a long, long time ago. But I suppose that's probably down to the stupid public spending priorities of successive Californian State governments and the people who elected them and failed to hold them accountable.

This guy has aerial footage from his own private plane, which is superb, but his nonchalant manner is simply astounding. This is a fairly major disaster already, and could become much worse...

More aerial video available here, start from 2.29...