#Hydraulic dam

[iowacitypast]

Iowa River and the Hydraulics Laboratory, The University of Iowa, October 24, 1923

Creator: Rumsey, A.L.

[m1male2]

Shushtar Hydraulic System.

Persepolis is not the only wonder of architecture in the Achaemenid era. Shushtar is an ancient fortress city in Khuzestan Province, Iran. The Shushtar hydraulic system, a masterpiece of creative genius, dates back to the reign of Darius the Great in the 5th century BC. The Shushtar hydraulic complex was a complex irrigation system consisting of two diversion canals on the Kârun River, one of which is still working to provide water to the city through a chain of tunnels.

This complex includes Salasel Castle, a tower for measuring the water level, dams, mills, bridges and basins. Water cascades down a dramatic cliff into a basin, then enters a plain located south of Shushtar, creating the possibility of farming on an area of ​​40,000.

“This systematic masterpiece is the result of the technical knowledge of the Mesopotamians and Elamites in ancient times that greatly surprises all viewers. Madame Jean Diolafoa, the famous French archaeologist, in her travel literature describes the Shushtar hydraulic system as the largest industrial complex before the industrial revolution.

[reasonsforhope]

"Beneath 1,350 square miles of dense jungle in northern Guatemala, scientists have discovered 417 cities that date back to circa 1000 B.C. and that are connected by nearly 110 miles of “superhighways” — a network of what researchers called “the first freeway system in the world.”

Scientist say this extensive road-and-city network, along with sophisticated ceremonial complexes, hydraulic systems and agricultural infrastructure, suggests that the ancient Maya civilization, which stretched through what is now Central America, was far more advanced than previously thought.

Mapping the area since 2015 using lidar technology — an advanced type of radar that reveals things hidden by dense vegetation and the tree canopy — researchers have found what they say is evidence of a well-organized economic, political and social system operating some two millennia ago.

The discovery is sparking a rethinking of the accepted idea that the people of the mid- to late-Preclassic Maya civilization (1000 B.C. to A.D. 250) would have been only hunter-gatherers, “roving bands of nomads, planting corn,” says Richard Hansen, the lead author of a study about the finding that was published in January and an affiliate research professor of archaeology at the University of Idaho.

“We now know that the Preclassic period was one of extraordinary complexity and architectural sophistication, with some of the largest buildings in world history being constructed during this time,” says Hansen, president of the Foundation for Anthropological Research and Environmental Studies, a nonprofit scientific research institution that focuses on ancient Maya history.

These findings in the El Mirador jungle region are a “game changer” in thinking about the history of the Americas, Hansen said. The lidar findings have unveiled “a whole volume of human history that we’ve never known” because of the scarcity of artifacts from that period, which were probably buried by later construction by the Maya and then covered by jungle.

Lidar, which stands for light detection and ranging, works via an aerial transmitter that bounces millions of infrared laser pulses off the ground, essentially sketching 3D images of structures hidden by the jungle. It has become a vital tool for archaeologists who previously relied on hand-drawings of where they estimated areas of note might be and, by the late 1980s, the first 3D maps.

When scientists digitally removed ceiba and sapodilla trees that cloak the area, the lidar images revealed ancient dams, reservoirs, pyramids and ball courts. El Mirador has long been considered the “cradle of the Maya civilization,” but the proof of a complex society already being in place circa 1000 B.C. suggests “a whole volume of human history that we’ve never known before,” the study says."

-via The Washington Post, via MSN, because Washington Post links don't work on tumblr for some godawful reason. May 20, 2023.

[materialsscienceandengineering]

Case Study: Sayano-Shushenskaya Power Station Accident

The Sayano-Shushenskaya is the largest power plant in Russia and one of the largest hydroelectric power stations in the world, by average power generation. Construction began in 1963 and the dam first began generating power in 1978. Around 30 years later, in August of 2009, turbine 2 failed catastrophically, flooding the turbine hall, collapsing a portion of the roof, and leading to widespread power failures in the region. Seventy-five people were reported killed in the accident. The reported cause of the failure was fatigue cracking due to poor and improper maintenance.

Sources/Further Reading: (Image source - Wikipedia) (Power Magazine) (Water Power Magazine) (Hydraulic Transients)

[mariacallous]

It’s been one of the wettest years in California since records began. From October 2022 to March 2023, the state was blasted by 31 atmospheric rivers—colossal bands of water vapor that form above the Pacific and become firehoses when they reach the West Coast. What surprised climate scientists wasn’t the number of storms, but their strength and rat-a-tat frequency. The downpours shocked a water system that had just experienced the driest three years in recorded state history, causing floods, mass evacuations, and at least 22 deaths.

Swinging between wet and dry extremes is typical for California, but last winter’s rain, potentially intensified by climate change, was almost unmanageable. Add to that the arrival of El Niño, and more extreme weather looks likely for the state. This is going to make life very difficult for the dam operators tasked with capturing and controlling much of the state’s water.

Like most of the world’s 58,700 large dams, those in California were built for yesterday’s more stable climate patterns. But as climate change taxes the world’s water systems—affecting rainfall, snowmelt, and evaporation—it’s getting tough to predict how much water gets to a dam, and when. Dams are increasingly either water-starved, unable to maintain supplies of power and water for their communities, or overwhelmed and forced to release more water than desired—risking flooding downstream.

But at one major dam in Northern California, operators have been demonstrating how to not just weather these erratic and intense storms, but capitalize on them. Management crews at New Bullards Bar, built in 1970, entered last winter armed with new forecasting tools that gave unprecedented insight into the size and strength of the coming storms—allowing them to strategize how to handle the rain.

First, they let the rains refill their reservoir, a typical move after a long drought. Then, as more storms formed at sea, they made the tough choice to release some of this precious hoard through their hydropower turbines, confident that more rain was coming. “I felt a little nervous at first,” says John James, director of resource planning at Yuba Water Agency in northern California. Fresh showers soon validated the move. New Bullards Bar ended winter with plumped water supplies, a 150 percent boost in power generation, and a clean safety record. The strategy offers a glimpse of how better forecasting can allow hydropower to adapt to the climate age.

Modeling studies have long suggested that better weather forecasts would be invaluable for dam managers. Now this is being confirmed in real life. New Bullards Bar is one of a half-dozen pilot sites teaming up with the US Army Corps of Engineers to test how cutting-edge forecasting can be used to optimize operations in the real world. Early tests of the methods, called forecast-informed reservoir operations, have given operators the confidence to hold 5-20 percent reserve margins beyond their reservoirs’ typical capacity, says Cary Talbot, who heads the initiative for the Army Corps.

To Talbot, FIRO could mean a paradigm shift in how the Corps and others run dams. Historically, dam operators under the Army Corps umbrella had to ignore weather forecasts and respond only to rain and snow that was already on the ground. This rule traces back to the notorious capriciousness of traditional forecasts: If an operator takes a bad gamble on a forecasted weather event, the results can be dangerous. But in practice, this forces operators to react later than their gut tells them to, says Riley Post, a University of Iowa researcher who spent over a decade as a hydraulic engineer for the Corps. They might, for example, be expected to hold water in a nearly full reservoir even as heavy rains approach.

Recent developments, however, have sharpened the trustworthiness of forecasts, particularly for atmospheric rivers on the West Coast. Leaps in computing power have enabled ever-more-muscular climate and weather modeling. To pump these models with data, scientists led by the Scripps Institution of Oceanography have since 2016 launched reconnaissance flights over atmospheric rivers of interest, where they release dozens of dropsondes, sensor packs shaped like Pringles cans. The result is a detailed profile of a storm’s strength, size, and intentions, which can then feed into FIRO.

These reports aren’t clairvoyant; all weather forecasts involve a measure of uncertainty. But a dam operator with increased confidence in when, where, and how much water will strike their watershed can take a more “surgical” approach to holding or releasing water, Post says.

And if they know how much time they have, they can also make the most of their existing water. Take Prado Dam, a vintage 1941 facility that was built to shield Orange County from flooding but can also distribute water to 25 groundwater-recharge stations. This past winter, forecasts showed a well-spaced parade of storms tracking its way. So operators pulsed water from the dam into storage at an optimal cadence, giving it time to soak into the landscape. Adam Hutchinson of the Orange County Water District, which manages the groundwater-recharge system, said publicly in July that these actions delivered an “exceptional” boost to water supplies for “those dry years we know are coming.”

Jinsun Lim is an analyst with the International Energy Agency think tank who studies climate resilience in the energy sector. Lim says that this sort of specificity is exactly what hydro officials in many countries wish for: tools that can translate climate impacts at a local level for their unique watersheds and infrastructure. Talbot hasn’t seen anything quite like FIRO deployed abroad, but he says that curious parties from the UK, Chile, Southeast Asia, Australia, and other regions have contacted him. Meanwhile, other corners of the hydro world are applying similar logic to their own climate challenges.

For BC Hydro, which serves 95 percent of British Columbia’s population, heat waves have proven a bigger problem than drought. Rivers and rains remain strong, but the province’s historically mellow springs and summers have warmed up, prompting many people to switch on air conditioners, which jacks up power demand. To keep the ACs humming, BC Hydro keeps a close eye on its fuel supply, that is, its watershed. About 150 monitoring stations, equipped with snow, climate, and surface-water sensors, enable a near-real-time picture of water flows. This helps operators store up water for demand spikes in summer and winter alike.

Tajikistan, which gets fully 98 percent of its power from hydroelectricity, is adapting its fleet with a mix of hard and soft measures. Renovations at the 126-megawatt Quairokkum power plant, built in 1956, were screened against a range of climate scenarios—such as the diminution of its source glaciers. Just replacing its six Soviet-era turbines will hike output to 170 megawatts; the dam will also be reinforced for a 10,000-year flood whose intensity could exceed the previous design standard by anywhere from 15 to 70 percent. Meanwhile, investments by international funders in HydroMet, the country’s long-dysfunctional meteorology service, are paying off: The agency recently gave power generators early notice of a dry year, enabling forward planning.

Recent trends have underlined the need for such changes. Earlier this year, the International Energy Agency said today’s hydropower facilities are on average 2 percent less productive than dams were from 1990 to 2016. Droughts have weakened flows at many plants, the agency said, leaving fossil-based energy to fill a gap the size of Spain’s annual power use. Other dams have been exposed to extreme events for which they weren’t strictly engineered, as in north India in 2021, when a crumbling glacier sent forth a wall of water that wrecked dams and towns downstream. Last month’s disaster in Libya, due to the failure of two flood-control dams hit by a supersized Mediterranean storm, further underlines the risks of maladapted facilities.

Even hydropower’s harshest critics take no issue with nip-and-tuck improvements at today’s dams. But amid a massive expansion planned in the Global South, they warn against overconfidence that hydropower can adapt its way out of climate change. In July, an environmental group in Namibia urged the government to rethink a large dam proposed for the Kunene River, saying it’s prone to the same climate extremes that have sapped the energy of Namibia’s other dams.

As climate disruption sets in, solar and wind can provide equivalent power with less risk, says Josh Klemm, co-executive director of International Rivers, a human rights organization focused on river communities. “We need to really reexamine plans to develop new hydropower,” he says. “We’re only going to deepen our reliance on a climate-vulnerable energy source.”

The Army Corps, meanwhile, is in the early stages of studying whether FIRO can be attempted at 419 other dams under its umbrella. Scaling up FIRO isn’t entirely straightforward; other parts of the US have different kinds of precipitation events than California does, and some of these are currently a lot harder to predict than atmospheric rivers. But Talbot is optimistic that the ever-improving forecast science can find efficiency gains there for the taking. “It’s making your existing infrastructure work harder for you,” he said. “In the face of climate change, this sounds like a great way to position ourselves for buffering that.”

[fatehbaz]

In 1678, a Chaldean priest from Baghdad reached the Imperial Villa of Potosí, the world’s richest silver-mining camp and at the time the world’s highest city at more than 4,000 metres (13,100 feet) above sea level. A regional capital in the heart of the Bolivian Andes, Potosí remains – more than three and a half centuries later – a mining city today. [...] The great red Cerro Rico or ‘Rich Hill’ towered over the city of Potosí. It had been mined since 1545 [...]. When Don Elias arrived [...], the great boom of 1575-1635 – when Potosí alone produced nearly half the world’s silver – was over, but the mines were still yielding the precious metal. [...]

On Potosí’s main market plaza, indigenous and African women served up maize beer, hot soup and yerba mate. Shops displayed the world’s finest silk and linen fabrics, Chinese porcelain, Venetian glassware, Russian leather goods, Japanese lacquerware, Flemish paintings and bestselling books in a dozen languages. [...]

Pious or otherwise, wealthy women clicked Potosí’s cobbled streets in silver-heeled platform shoes, their gold earrings, chokers and bracelets studded with Indian diamonds and Burmese rubies. Colombian emeralds and Caribbean pearls were almost too common. Peninsular Spanish ‘foodies’ could savour imported almonds, capers, olives, arborio rice, saffron, and sweet and dry Castilian wines. Black pepper arrived from Sumatra and southwest India, cinnamon from Sri Lanka, cloves from Maluku and nutmeg from the Banda Islands. Jamaica provided allspice. Overloaded galleons spent months transporting these luxuries across the Pacific, Indian and Atlantic oceans. Plodding mule and llama trains carried them up to the lofty Imperial Villa.

---

Potosi supplied the world with silver, the lifeblood of trade and sinews of war [...]. In turn, the city consumed the world’s top commodities and manufactures. [...] The city’s dozen-plus notaries worked non-stop inventorying silver bars and sacks of pesos [...]. Mule trains returning from the Pacific brought merchandise and mercury, the essential ingredient for silver refining. [...] From Buenos Aires came slavers with captive Africans from Congo and Angola, transshipped via Rio de Janeiro. Many of the enslaved were children branded with marks mirroring those, including the royal crown, inscribed on silver bars.

Soon after its 1545 discovery, Potosí gained world renown [...]. Mexico’s many mining camps [...] peaked only after 1690. [...] Even in the Andes of South America there were other silver cities [...]. But no silver deposit in the world matched the Cerro Rico, and no other mining-refining conglomeration grew so large. Potosí was unique: a mining metropolis.

Thus Don Elias, like others, made the pilgrimage to the silver mountain. It was a divine prodigy, a hierophany. In 1580, Ottoman artists depicted Potosí as a slice of earthly paradise, the Cerro Rico lush and green, the city surrounded by crenellated walls. Potosí, as Don Quixote proclaimed, was the stuff of dreams. Another alms seeker, in 1600, declared the Cerro Rico the Eighth Wonder of the World. A [...] visitor in 1615 gushed: ‘Thanks to its mines, Castile is Castile, Rome is Rome, the pope is the pope, and the king is monarch of the world.’ [...]

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For all its glory, Potosí was also the stuff of nightmares [...].

Almost a century before Don Elias visited Potosí, Viceroy Francisco de Toledo revolutionised world silver production. Toledo was a hard-driving bureaucrat of the Spanish empire [...]. Toledo reached Potosí in 1572, anxious to flip it into the empire’s motor of commerce and war. By 1575, the viceroy had organised a sweeping labour draft, launched a ‘high-tech’ mill-building campaign, and overseen construction of a web of dams and canals to supply the Imperial Villa with year-round hydraulic power, all in the high Andes at the nadir of the Little Ice Age. Toledo also oversaw construction of the Potosí mint, staffed full-time with enslaved Africans. [...] Toledo’s successes came with a steep price. Thanks to the viceroy’s ‘reforms’, hundreds of thousands of Andeans became virtual refugees (those who survived) and, in the search for timber and fuel, colonists denuded hundreds of miles of fragile, high-altitude land. [...] The city’s smelteries belched lead and zinc-rich smoke [...].

The Habsburg kings of Spain cared little about Potosí’s social and environmental horrors. [...] For more than a century, the Cerro Rico fuelled the world’s first global military-industrial complex, granting Spain the means to prosecute decades-long wars on a dozen fronts – on land and at sea. No one else could do all this and still afford to lose. [...]

By [...] 1909 [...], mineral rushes had helped to produce cities such as San Francisco and Johannesburg, but nothing quite compared for sheer audacity with the Imperial Villa of Potosí, a neo-medieval mining metropolis perched in the Andes of South America.

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Text by: Kris Lane. “Potosi: the mountain of silver that was the first global city.” Aeon. 30 July 2019. [Bold emphasis and some paragraph breaks/contractions added by me.]

[basicgeology]

Knickpoints, base level, and waterfalls

I won't go into detail about hydraulics, but hi! Let's talk about rivers a little!

Base level: in geomorphology, the "base level" is the lowest point at which erosion can occur, or in the case of rivers, it's the lowest altitude at which a river can flow. A common base level for most rivers is the sea, though for some of them it might be a lake, a different river that the first river is a tributary to, or a dam.

The base level for any given river can change through time, since sea levels can vary, dams can be built, etc. A variation in base level, causes a variation in the river's energy, which can lead to more erosion, or more sediment deposition depending on if the river has more or less energy than before.

Here are two examples, the first is of a river whose base level dropped lower, it gained more energy and started eroding the substrate more, the second one is of a river whose base level was raised higher, and it started depositing more sediment to compensare with lowered energy.

This was an introduction to explain the concept of base level, now let's move on to knickpoints.

Knickpoint: a sudden and sharp variation of a river's slope, often leading to the formation of waterfalls and/or lakes. Some reasons why a knickpoint might form are: base level drop, tectonic activity, or a later of erosionally resistant rock:

There are generally two types of knickpoints: migrating and fixed.

Migrating knickpoints are mainly caused by base level drop and tectonic activity. They are called migrating because due to the erosion that the river applies on the substrate, the knickpoint is able to travel upstream. In the case of a base level drop type of knickpoint that affects an entire hydrography basins, usually the baisin will have all of its migrating knickpoints at the same altitude:

Sometimes, knickpoints are caused by differential uplift (two areas within a hydrographic basin are subject to different rates of tectonic uplift), and this causes a "barrier" of knickpoints that can easily be drawn within the baisin:

Fixed knickpoints instead are caused mostly by the presence of a layer of erosionally resistant rock, as it is something that the river cannot easily erode through, and will remain fixed.

Waterfalls can form from any of these kinds of knickpoints, it really depends on the river's erosion ability, it's energy, it's mass flow rate, the kind of sediments it carries, etc.

[noirandchocolate]

Pyramids are dams in the stream of time.  Correctly shaped and orientated, with the proper paracosmic measurements correctly plumbed in, the temporal potential of the great mass of stone can be diverted to accelerate or reverse time over a very small area, in the same way that a hydraulic ram can be induced to pump water against the flow.

The original builders, who were of course ancients and therefore wise, knew this very well and the whole point of a correctly-built pyramid was to achieve absolute null time in the central chamber so that a dying king, tucked up there, would indeed live forever–or at least, never actually die.  The time that should have passed in the chamber was stored in the bulk of the pyramid and allowed to flare off once every twenty-four hours.

After a few eons people forgot this and thought you could achieve the same effect by a) ritual b) pickling people and c) storing their soft inner bits in jars.  

This seldom works.

--Terry Pratchett, “Pyramids” (SELDOM works???)

[rabbitcruiser]

Pantà de la Baells, Spain (No. 1)

The Baells reservoir is a Spanish hydraulic infrastructure located on the Llobregat River, in the Bergadá region, province of Barcelona, Catalonia. It consists of a dam located in the municipality of Serchs. It extends through the terms of Serchs and Vilada, between the pre-Pyrenean mountains of Catllarás, to the east, and Figuerassa and Arades, to the west. To the right of the reservoir runs the C-16 road, between the Cadí tunnel and Berga-Manresa, and is crossed by the C-26, which links Berga and Ripoll.

The aim of the reservoir is to regulate the upper basin of the Llobregat River, supply water to the metropolitan area of Barcelona and produce hydroelectric energy.

Source: Wikipedia

[silverslipstream]

An Acquired Taste

It was an uncommonly hot autumn day when Yulia Lebedeva first tasted fruit.

By the standards of New Seoul, the phrase ‘uncommonly hot’ seemed naive. From the great hydro-powered pumps and dams working around the clock to keep the Yellow Sea at bay, to the multicoloured throng of fans whirring from roadside bazaars, the city of twenty-six million was shaped, moulded, created by heat. It may not have been Hell, but there was no denying both places had a connection to the same feverish warmth.

The teeming thoroughfare of Sambong-ro yawned before her. Rickshaws shot past lumbering solar landbarges, the cacophony of pedalling legs and hydraulic whines drowned out by the background hum of sheer humanity. The pavements and main roads were supposed to be a pristine, reflective white: years of wear underfoot had turned them into a dirty ochre. It reminded Yulia of videos she’d seen about the Amazonian savannah, and the humans crawling across it of the late wildebeest; flowing like sand through fingers. Despite each individual destination, the masses kept an unconscious, graceful totality quite unlike anything she’d ever seen.

Nevertheless, it was a little overwhelming. Shuffling left past a haggling seaweed-seller and kicking aside a discarded plastic bag, Yulia eased her way into a claustrophobic canyon. Her first thought was that the sun had been inexplicably cut off; the staggering heights of the surrounding buildings had plunged this narrow alleyway into a strange twilight. Whereas before she had been sweating in the stagnant humidity, now an artificially funnelled breeze was at her back. 

The light was bluer here, relying more on artificial lighting than the meagre strip of sky daubed overhead. Faded, mottled walls, a pervading sickly stench and a collection of ramshackle vendor’s huts conveyed the area’s poverty. A window-mounted softscreen overhead flickered and buzzed, sending a trail of boron-green sparks skittering down like ash from a cigarette’s tip. Music quietened as she walked further; the clang of metal gantries echoed above as inquisitive inhabitants rushed out, peering closely at the presumably lost foreigner.

The stench grew stronger as she reached the vendors and their wares; the faint, leafy scent of algae vats, the spicy, cloyingly sweet tang of soy-beef and the metallic stink of blood and assorted bodily fluids. An old lady, perched behind what looked to be a fruit stall, yelled a few words in what sounded like Mandarin. Yulia smiled back in what she hoped was an encouraging way and pointed to the translator device looped around her left ear. A moment later, the fruit seller’s words were whispered in perfect, monotone English, directly into her ear.

“Hey! Lost lady! Want to try some fruit? Real fruit, from Hokkaido, not vat-grown, no soy-fruit! 60 Sphere-yuan each!”

Real fruit? From a real tree? I’ll believe it when I see it, thought Yulia. The few remaining fruit plantations were guarded and tended to by corporations or the ultra-rich; not piled in front of a stall in some backwater New Seoul alley. She peered closer; the fruits were pear-shaped and a deep ruby red, with small green seeds rippling their skin. It was probably just another vat-grown scammer, she rationalised to herself.

Yet, her curiosity was piqued.

“Can I…” Yulia said slowly in English, pointing to herself, “...try one first?” she asked, pointing to the fruit and miming a bite. The woman nodded, and held out her right index finger to transfer the funds. Yulia’s fingerpad pressed against the old woman’s for a moment, then down, grabbing a fruit from the topmost row. A sharp word was uttered by the seller as Yulia brought the fruit to her lips.

“Enjoy!” said the translator as she bit down.

Her first thought was confusion. The flesh of the fruit was moist but not juicy, and had a surprising amount of thickness to it. It was almost…chewy? Crisp sweetness rolled around her mouth, a sugary taste so unlike the food tubes she was used to back home at the Institute. The seeds stuck to her teeth and cracked: they filled her mouth with a tart, sour tang. It seemed similar to the flavour pouches she’d once eaten marked ‘passionfruit’ yet a world away in execution. Delicious had never before seemed so ordinary a word.

“What…” Yulia asked, pointing at the fruit in an almost reverent way, “is this called?” 

The fruit seller smiled, straightening her apron as she talked. The grin splitting her face made it seem as if she was chatting to an old friend.

The translation device filled in the gaps: her son was a genesplicer in Hokkaido North, and had sent his mother a bag of his corporation’s newest crop. Bad reviews had sunk the fruit’s commercial rating while thousands were still to be harvested; therefore, her son could send these discarded fruits to New Seoul for a very low price.

Yulia nodded. “How much for the rest?” she said, pointing at several fruits and then at her index finger.

“If you want a dozen, I'll charge 550 Sphere-yuan. Save you some money.”

Yulia shook her head and swept her arm in a wide arc, over all of the fruit. The old woman’s eyes widened and she ducked below the booth, muttering too faintly for the translator to hear. A moment later, she resurfaced with a fabric bag clutched tightly in her gnarled right hand.

“3,000 Sphere-yuan for the lot. You sure? I’ll tell my son: his fruit may not be successful in Hokkaido, but it certainly is here!”

Yulia nodded. Taking the proffered bag and briefly touching fingers again, she placed each fruit into the plastic bag, taking meticulous care not to bruise it. If she could return to the Institute with some of this… reverse-engineer it in the genetics lab… why, the fruits would be worth their weight in gold. No flavour pouch, no algae, no soy-meat would ever come close to the taste she had just experienced.

Smiling, she bowed to bid the fruit seller farewell, and continued further into the artificial canyon she found herself in. As the stall receded, the translator picked up one last, garbled whisper from the old woman’s direction.

“Tourist,” it said. Yulia thought she could feel the contempt, hidden somewhere in its impersonal tone.

[dailyanarchistposts]

Mega Schemes

Huge hydraulic schemes are made possible by advanced modern civil engineering techniques. They require vast international contracts that are only possible at the level of central governments, international free floating capital and supranational government organisations. The financiers borrow money and lend it at commercial rates, so they favour largescale engineering projects that promise increasing production for export markets at the expense of local subsistence economies, with disastrous social and environmental effects. Cash crops destroy settled communities and cause pollution of soil and water. For instance, Ethiopia’s Third Five-Year Plan brought 60% of cultivated land in the fertile Awash Valley under cotton, evicting Afar pastoralists onto fragile uplands which accelerated deforestation and contributed to the country’s ecological crisis and famine. There’s a vicious circle at work. Development needs money. Loans can only be repaid through cash crops that earn foreign currency. These need lots more water than subsistence farming. Large hydraulic schemes to provide this water are development. Development needs money. And so it goes.

Large-scale projects everywhere are the consequence and justification for authoritarian government: one of America’s great dam-building organisations is the US Army Corps of Engineering. Stalin’s secret police supervised the construction of dams and canals. Soldiers such as Nasser of Egypt and Gadafi of Libya and military regimes in South America have been prominent in promoting such projects. Nasser built the Anwar High dam in 1971. The long-term consequences have been to stop the annual flow of silt onto delta land, requiring a growing use of expensive chemical fertilisers, and increased vulnerability to erosion from the Mediterranean. Formerly the annual flooding washed away the build-up of natural salts; now they increase the salt content of irrigated land. The buildup of silt behind the dam is reducing its electricity generating capacity; the lake is also responsible for the dramatic increase in water-borne diseases. Nationalism leads to hydraulic projects without thought to what happens downstream in other countries. The 1992 floods of the Ganga-Brahmaputra-Barak system killed 10,000 people. 500m people live in the region, nearly 10% of the world’s population, and they are constantly at risk from water exploitation and mismanagement. Technological imperialism has replaced the empire building of the past: large-scale hydro projects are exported to countries despite many inter-related problems – deforestation, intensive land use and disputes and so on. Large-scale water engineering projects foment international disputes and have become economic bargaining counters, for example the Pergau dam in Malaysia. The British Government agreed to spend £234m on it in 1989 in exchange for a £1.3bn arms deal. In 1994 the High Court ruled that the aid decision was unlawful but these kinds of corrupt deals continue.

In Sri Lanka the disruption caused by the Mahawelli dams and plantation projects resulted in the forcible eviction of 1 million people and helped maintain the insurgency of the Tamil Tigers that resulted in thousands of deaths as they fought government forces from the late 1980s onwards. In 1993 the Marsh Arabs of southern Iraq were threatened by Saddam Hussein’s plans to drain the area – the most heavily populated part of the region. Many of the 100,000 inhabitants fled after being warned that any opposition risked death. Selincourt estimated that 3 million people would lose their homes, livelihoods, land and cultural identity by giant dam projects in the 1990s. The Kedung Ombo dam (Indonesia) displaced 25,000; the Akasombo dam (Ghana) 80,000; Caborra Bassa (South Africa) 25,000. Three dams in Laos alone will have displaced 142,000 people. The proposed Xiao Langdi dam in China would displace 140,000; the Three Gorges project 1.1 million people. Only war inflicts a similar level of human and environmental destruction, yet large dam projects have a chronic record in delivering water and power, or eliminating flooding in downstream valleys.

[redheadedgirl]

My son has decided that dams are his focus for the day, and we’re leaning into it for homeschooling.

Now I get to hear about him building a dam turbine, a dam structure, we took a dam walk to see the local dam. Now he’s wondering if there are dam hydraulics. He drew a dam diagram, did a dam coloring page, and we watched some dam videos. He’s got more dam knowledge in his little noggin than most 7 year olds and he’ll gladly explain to you how the dam water turns into dam power (it’s dam turbines and generators).

I am delighted and he has no idea that there’s a joke floating around in all this. He’s just excited about dams.

[swedebeast]

Oh yeah, hard to miss the news yesterday about the big as hell dam breaking in Ukraine. I have peripheral experience with hydropower, and I called pops to talk with the man about it - as he has worked in the biz for over 30 years.

And it was a bleak rundown I got. Normally, in any flood like this it leaves the farmland pretty much unusable for years with trash and debris floating over it - but the 150 tons of hydraulic oil will be the worst of it.

And that will likely destroy the farmland for years to come. And then there is not to mentioned the Russian landmines being washed away and deposited who knows where. If not blasting some poor farmer or child, they will rust and seep out chemicals into the ground around it.

And there is little chance of it being a Ukrainian operation. Russia threatened to destroy it before, and artillery will not break the concrete housing or the doors. It needs to be a deliberate task of sabotage to make that happen.

And this will be one mighty “F.U” to Ukraine to destroy the power infrastructure. But I somehow believe it is entirely in line with military commanders from that side of the conflict to make petty and vastly ill-informed decisions like these.

[floresjostyn]

Modern history: Water dams -a marvel of hydraulic engineering-

The first known dam to be built is the Jawa Dam, which is actually the largest in a series of dams that are all part of one reservoir system.

But… ¿What is a water dam?

A water dam is a kind of barrier that can sometimes prevent catastrophes because it restricts the use of surface water and subway streams, which prevents flooding and not only that, also provides people for different activities such as irrigation, human consumption, navigability, etc.. Dams often also provide hydroelectric power production and river navigation.

The origins of the first dam water are located in modern-day Jordan; the Jawa dam was originally constructed around 3,000 BCE in what was then Mesopotamia. Unlike ancient dams, the Jawa Dam was reinforced with rock fill behind the upstream wall in order to protect the wall from water pressure breach. The Jawa dam was the most important archaeological site in the history of large scale hydraulic projects, it was well designed and built, until later years it deteriorated due to a physical intervention. Different societies progressively evolved in the advancement of hydraulic engineering.

 

Approximately 400 years after the construction of the Jawa Dam, the Egyptians built a dam for the quarries in their area and not for irrigation, as the Nile River supplied enough water for the farmers. They took approximately 10 years with the construction of the dam, but due to poor design and structure, it was washed away during the heavy rains. Thanks to the first attempts, the civilizations of the following years were able to have a better idea in the design of water dams. The Romans also built the world's first arch dam in the Roman province of Gallia Narbonensis, present-day southwestern France, in the 1st century BC. They were also responsible for the first buttress dam constructions.  The Asians also contributed to dam engineering. During 400 AD they built earth dams to store water in different cities. The Sinhalese used these structures to form reservoirs to collect monsoon rains for their intricate irrigation system. Dam engineering did not improve until the 1850s, when civil engineering professor William John Macquorn Rankine of Glasgow University demonstrated a better understanding of ground stability and structural behavior. Thanks to Rankine, the understanding of dam engineering has improved significantly.

Between 1813 and 1910, British and French engineers contributed to major advances in concrete dams, which during that period recognized the complexity of the structure and understanding its interconnections, so that engineers were able to make exponential advances in dam engineering. 

Today, this deep understanding has resulted in the practice of digital modeling, which allows for multifaceted and comprehensive testing and examination of structural stability. Although dams have been built since ancient times, today we can see more significant contributions in dam engineering. Thanks to knowledge of the earth, it has been determined that some dams are detrimental to the planet's ecology and the United States has eliminated more than 900 dams. In addition, a better understanding of dam safety has advanced significantly in recent years.

In short, with the evolution of the constant construction of dams due to various factors or reasons, certain failures have been determined that functioned as support to avoid making the same mistakes in the following years. They were able to become well informed about different parameters that make up the dams and advances in hydraulic engineering made it possible for us to better understand the safety and structuring of dams for the most important thing, which is to ensure the basic needs of the population. It is here that the famous phrase "He who does not know his history, will be condemned to repeat it" applies, and it makes sense in all this analysis made of the chronological evolution of the construction of the dams.

[brightclothesforwinter]

Sneaking in right under the wire (it's 23:15 on the 21st where I am!) for @mdzswomen's week 3 - I'd only just been talking about the yanqing fix-it AU which is at least 50% an excuse to bang on about TCM, so when I saw that one of the themes was 'healing' that was obviously a sign.

So here's the very beginning, I make no promises about ever getting to the end, I am excruciatingly slow as a writer, but I think works OK as a self-contained piece in the meantime.

.

It happens like this: Wen-Zongzhu sends Wen Qing to the Cloud Recesses, to investigate their defences. Identify points of interest. She goes, because she must, her family's safety always held over her head, her little brother at her heels because that is all the concession she can wring.

She has her mission, which she cannot reject nor fail at.

She also has her calling as a physician, and even Wen-Zongzhu would not lightly command her to set that aside. He understands the levers of filial loyalty too well for that.

. . .

Wen Chao is not subtle, delivering them to the Cloud Recesses.

Wen Qing is extremely subtle. She wears a guest disciple's robes; encourages her brother to attend lectures on the men's side as she does on the women's. She is as confident as she can be in his safety, here, this quiet place set aside from the world, with its rules standing carven in changeless stone and apply equally to all. As siblings, they are granted guest quarters set between the two sides, allowing each family a little privacy.

Thus the Jiang are their neighbours, and Jiang Yanli is sweet and kind and friendly, and, to Wen Qing's trained eye, obviously unwell. She tires easily; pauses for breath on the steep paths where a stronger cultivator would not need to, and on some mornings she moves as stiffly as a much older woman. To have friends is a dangerous thing, in the Nightless City. But here - Wen-Zongzhu's plans will surely pose danger to Jiang-Zongzhu's only daughter, in the fullness of time, but Wen Qing's friendship will at least not make that danger worse. She cannot let her guard down - she can never let her guard down - but in this time, in this place, she need not be quite so guarded.

Should Wen-Zongzhu ever ask, she can say plainly and truthfully that she felt it wise to maintain a friendly facade, to avoid suspicion, and that she also felt there might be some value in gathering what observations she could of the Jiang sibilings, who can be expected to go on to be leader and first disciple of one Great Sect, and mistress of another.

As a physician and a friend, she offers, delicately, to examine Jiang Yanli.

Jiang Yanli has been examined and treated by any number of doctors. The flow of qi in her meridians is sluggish, her core correspondingly underdeveloped. She has been prescribed, at various times, exercises to stimulate qi movement, exercises to slow qi movement, and several entirely contradictory herbs; one of the ones she's been taking is probably partly responsible for the shortness of breath. It's obvious her esteemed professional colleagues have been grasping at straws.

It is not at all clear quite what is wrong with her meridians, but certainly something is. Were her core stronger, she would be at serious risk of qi deviation. Had certain of her prescribed treatments been effective, they would have caused a qi deviation. The blockages are partial and specific; at certain points, qi flow is restricted, and the regular core-strengthening exercises taught to cultivators' children have erratic results.

'A bit like a hydraulic dam,' Jiang Yanli says, explaining Wen Qing's findings to her brothers. The metaphor would not have occurred to her, but Wen Qing supposes it is natural to Lotus Pier's children to think first of water.

A-Ning is somewhat distressingly impressed with Jiang Yanli's shidi; his confidence, mostly, but also his innovative thought-processes. He is, she will grudgingly admit, intelligent and creative, at least when it comes to matters not involving Lan-er-gongzi. And he is in fine form now, theorising noisily aloud and messily on paper, while Wen Ning grinds ink and Wen Qing intervenes when his lack of medical knowledge leads his flights of fancy too far astray.

She is sharp-tongued by habit, but he seems, if anything, grateful to be corrected - his grin is quite indecorous - and Jiang Yanli's smile is soft, watching them all. It is possible Wei Wuxian is as brilliant in his own field as she is in hers. It is possible that together they can come up with something which might not do more harm than good.

'You do both like a challenge,' Jiang Yanli says, gentle and amused, as she draws Jiang Wanyin away from the increasingly involved discussion.

Jiang Wanyin is the most reserved; the most aware, despite being youngest, of the prospect that war will divide them. Not that Yanli-mei is unaware, but she chooses to take the moments they have, to offer friendship now, and leave the things that must divide them to their own time.

Wei Wuxian quite possibly does not think beyond the current moment. It is possible that without the project to help his beloved sect-sister keeping his mind occupied, he would be getting into even more trouble, from restless boredom and what she suspects isn't so much an inability to grasp the concept of decorum, but the inability to remember, in the pinch, that it matters.

They are unlike anyone she has ever known. His brilliance would not have saved him from his inability to play politics, among the Wen, and what would have become of Yanli-mei's gentleness doesn't bear thinking about. Jiang Wanyin might, perhaps, have learnt to curb his temper into bitter viciousness before he pulled the tiger's tail too hard.

There are dozens of arrays the Jiang use for the general purpose of clearing the river-ways. Some are ancient, passed down through the generations; others, Wei Wuxian has already had a hand in refining. They are, she learns, different for an obstruction which is floating or submerged, partial or complete, if it is of earth or of wood, or some combination. There is one for metal, mostly employed in retrieving dropped tools, several which put her in mind of the greater yang meridians, but are apparently employed in particular hydrological circumstances she still doesn't entirely grasp despite an enthusiastic attempt to make a miniature demonstration in sand, and one untested and entirely theoretical creation of Wei Wuxian's which he claims would be effective in the deeply implausible scenario that the flow of the river was somehow blocked by fire.

Implausible as a behaviour of physical geography, at least. As a political statement, that time may well come. And as an analogy to the flow of qi and the functioning of the body - the river-management arrays are the key she needs.

. . .

Wei Wuxian is protective; Jiang Wanyin is brusquely sceptical; Yanli-mei is steadfast and resolute. "Let us," she says quietly, "attempt the impossible."

Wen Qing is cautious. The first treatment is brief, tentative, the application of the smallest amount of energy she can muster to one of the blockages of the liver meridian. It is appropriate in function, it is a faint meridian, and most importantly for this experiment, it is a yin meridian; her own cultivation energies suffice, filtered through an array they have adapted from one which would be used to break up a submerged partial blockage of wood in circumstances where the disruption downstream must be minimised. She carries out the treatment at the hour of the sheep, when it will have the mildest possible effect, with all three of their brothers waiting anxiously on the other side of the privacy screen.

The liver meridian opens into the eyes. When Yanli-mei opens eyes just a little brighter, Wen Qing believes that it has worked.

When she actually snaps at her brothers for fussing over her, she is certain; the liver is also the seat of anger.

Nonetheless, she chases the boys away again, examines her patient's pulse and tongue, and traces the meridian from toe to crown before she pronounces their experiment a tentative success.

It is fortunate they did not attempt this experiment at the hour of the ox; Wei Wuxian actually whoops in triumph.

For the next few days, Wen Qing attends the women's lectures, observes her patient, and documents her process. Wen-Zongzhu gave instructions regarding the secrecy of her mission here, but none concerning any unexpected advances in medical cultivation. Nor is it something he is at all likely to enquire about, afterwards. She takes a copy to the Lan healers, for their knowledge and their archives; speaks quietly and respectfully, and tells them she feels it is always wise to keep multiple copies of such things. She dare not give voice to any more direct warning, but perhaps it will be enough.

They concur with her plan to address Yanli-mei's meridians by pairs, which if nothing else speaks well of their competence. There will be imbalances over the proposed six days of treatment, but to address all in one day cycle would be excessively strenuous for both patient and healers.

One of the Lan healers is a tall, quiet woman who - with obvious discomfort - describes herself as 'uniquely qualified' to assist with the yang-dominant meridians for the sake of decorum; Wen Qing thanks her kindly, but says she is accustomed to working with A-Ning, and that Yanli-mei's brothers are surely suitable chaperones. Delicacy and precision matter more for this than cultivation power or healing skill, and she is accustomed to directing him. That, too, is a hint, perhaps; that her didi has more skills than grinding her inks, brewing her herbs, and preserving her reputation as a young woman among men.

She leaves with a copy of one of their oldest and most poetically obscure treatises on healing, an invitation to study their other medical texts, and written permission for the five of them to rise at the hour of the tiger, to most effectively begin the treatments of the lung meridian.

. . .

Even in summer, the tiger hour is dark; when she and A-Ning cross the courtyard to the Jiangs' guest-house, and here on the mountain-side it is even a little cool.

Jiang Wanyin is groggy, grumpy, afraid for his sister, and trying with limited success to conceal all three. Wei Wuxian has obviously not slept at all, and can apparently keep quiet or still but not both. And Yanli-mei - her face is a pretty mask. A stranger would think her neither tired nor anxious, but she is brewing tea, and steaming sweet buns she must have prepared last night. Yanli-mei's anxieties manifest in food, drink, and practical matters, just as her discomfort manifests in warm politeness.

Even with a limited palette of ingredients, she is an exquisite cook. It speaks, perhaps, to a childhood less idyllically carefree than Wen Qing first thought.

The existing river-clearing array for metal prioritised intact recovery of valuable tools; the synthesis to one which would break down harmlessly was predominantly Wei Wuxian's work, checked over by Jiang Wanyin with his more reliable eye for detail. She has had them both check over her own work, the further conversion from the hydrological context to the medical.

She works methodically. The Jiangs have been at pains to warn that clearing a blockage upstream risks flooding - or in this case, qi deviation - downstream; she works in reverse, from the thumbs to the triple-burner, opening each blockage only a little on the first pass. It takes three passes, overall, and Yanli-mei slips into a drowsy doze, though this cannot be comfortable. The hour is almost over by the time she can remove her needles and rouse her patient.

Beyond the screen, their brothers have fallen quiet. Perhaps sleeping. She is the only one who hears Yanli-mei whisper, "it's so unfair," with tears welling in her dark eyes.

"It is," Wen Qing whispers back, holding her close. It might be her health, the incompetence of her previous doctors, whatever family trouble it is that has left her so inclined to make herself small, to show her love in practical ways, to wear a smiling face and play the peacemaker. It might be something else entirely, but Wen Qing does not for a moment doubt that it is unfair. Many things are.

The moment passes, as these moments do. Yanli-mei steadies her breath; dries her eyes. Presses her palms together as if to apologise -

- Wen Qing catches her forearms. "The lungs are the seat of grief. It is natural that your buried griefs would surface. It will pass."

Yanli-mei nods. "It is better," she says quietly, "that we are here."

And not in Yunmeng.

They wake their brothers; Jiang Wanyin gruffly insists on taking charge of the brewing of fresh tea. Outside, the dawn is breaking.

It requires several folded blankets and a certain amount of experimentation to position Yanli-mei so that she is sitting comfortably enough, but Wen Qing is still able to place all the necessary needles. Only when they are both satisfied does she call A-Ning and move the screen aside. She would sooner not have the distraction, but decorum is better satisfied if Yanli-mei's brothers are present and able to swear there has been nothing untoward; their word will carry more weight than hers.

There is nothing indecorous about the process, even by non-medical standards. Each array is bound to a pair of needles; A-Ning sits at the table where they are laid out, weighted down by pebbles from the courtyard garden, and applies power as Wen Qing directs. She is distantly conscious of the weight of Yanli-mei's brothers' attention, aware enough of Yanli-mei's swelling sadness to give an occasional, careful squeeze to the last three fingers of her hand, where the needles are not, but otherwise intensely focused on her patient's meridians and her shifting pulse-patterns.

"That smells wonderful," Yanli-mei says, as Wen Qing rises from the haze of concentration.

"It's plain rice porridge, again," Wei Wuxian replies, in a voice for tragedies, and almost drops the bowls he is setting out on the table.

It's Jiang Wanyin who actually explains, busy with brazier and kettle again. "The Lan kitchens sent someone with a tray." Wen Qing removes her needles and finds Yanli-mei a cloth to wipe her face and blow her nose, while A-Ning carefully rolls and ties the papers with the arrays, and sets them with Wen Qing's other tools.

Yanli-mei is shaky on her feet, when Wen Qing helps her up, but she insists on going to her brothers, drawing them away from their separate tasks.

"I am so sorry," she murmurs, embracing them both at once, and Wen Qing takes over the tea-making and files away the apologies she can't help but hear. The Violet Spider naturally favours her own son, while Jiang-Zongzhu, somewhat less naturally, shows greater favour to Wei Wuxian. Yanli-mei, she suspects, has been mediating between the four of them almost her whole life.

It's an exploitable rift, and Wen Qing wishes she didn't have to know that. She doubts it will be something she is able to keep back, when Wen-Zongzhu questions her.

. . .

They rest for the remainder of the morning, and attend the afternoon lectures, even Yanli-mei, who insists that major medical treatment or not, she feels at least as well as she ever has, and that she can't bear to lose any more time to lying around and resting. She sticks close to Wen Qing, wreathed in formless sadness, until one of the Jin girls - not Mianmian, the one with the sharp eyes who Wen Qing is certain is viciously jealous of her sect-sister's standing - raises an eyebrow at the pair of them together. Wen Qing is inclined to lift her chin and ignore her, secure in her own standing, but Yanli-mei steps forward, greets the snake with her usual impeccable manners, and says smoothly, "you know, of course, that this one's health has always been poor; since we are study-sisters here, the renowned physician-jie has kindly condescended to offer her skills." Which is several shades more polite than the first daughter of the Jiang needs to be to an Jin outer disciple who is not even particularly skilled in any regard herself, but there is the betrothal; perhaps Yanli-mei schemes to ensure these ones will look on her with kindness, later.

Their lecture is otherwise uneventful; the focus is on the various kinds of ghost for which a woman cultivator is most likely to be called; there are several which are particularly known to trouble brides-to-be, newlywed women, and those carrying a first child, and it is regrettably common for the afflicted young women to die because their families hesitated to bring a strange man into the household until it was too late.

Wei Wuxian's already poor impulse-control is, naturally, made worse by the lack of sleep; whatever he says in the men's lecture - or possibly the manner in which he says it - infuriates the teacher badly enough that he is confined to the library, copying the Lan code of conduct under Lan-er-gongzi's supervision.

Wen Qing and Yanli-mei request that he be permitted to absent himself from that task the following morning to be present for the treatment of Yanli-mei's stomach and spleen meridians. It is Wen Qing's reasoning - that opening these meridians will bring Yanli-mei's buried worries to the surface, and that to have both her brothers present will be some reassurance - but it is Yanli-mei's earnest, apologetic mien which wins them that concession.

The treatment goes as well as Wen Qing could have hoped for. Yanli-mei's worries are regrettably informative; of course - especially after yesterday's lecture - she worries for own future, as anyone would whose betrothed shows so little care for them; who will be her defender, alone and unwanted in the halls of Jinlintai?

She worries for her parents and her brothers, without her there to play peacemaker. Shocked protest, from them both, until Wen Qing rolls her eyes and points out that she can see exactly what Yanli-mei means, that they don't know how to express affection without shoving and fighting and sharp words; that they hurt each other, sometimes, and that she is always the one to help them reconcile.

Perhaps that has given them thought. Perhaps it will help.

The third concern is nothing Wen Qing can set at ease. Yanli-mei sees the way the wind is blowing, as clear as Wen Qing does; that there is war on the horizon, and it will set them on opposite sides. "You are not here to learn," she says, in a whisper, Wen Qing's hand clutched in hers.

Wen Qing could deny it. It wouldn't even be a lie; it's just that the things she is here to learn are not what the Lan are intending to teach.

"And yet I have," she murmurs instead. "I was not sent here to make friends, either, and yet."

"Must it come to war?" Yanli-mei the peacemaker pleads.

There is no kind way to say it. "The alternatives are worse." Wen-Zongzhu's ambitions will not be stopped by anything less, but that, she cannot say aloud. A fine line. "I wish it were not so." Yanli-mei is soft and kind and delicate over a core of determined practicality. She is as precious and lovely in Wen Qing's eyes as she is in her brothers', and Jin Zixuan is a fool not to see it. "That we might choose a path for ourselves, and not be pulled apart by duty."

"Even the boys don't get that freedom; what hope have we?"

"Tomorrow will be better," Wen Qing replies.

. . .

Tomorrow is better, but only because the heart is the seat of joy, Wei Wuxian's theoretical fire-blockage array works as intended, and Yanli-mei's joy is contagious. They have skipped the afternoon lecture for the treatment, and she spends the monkey and rooster hours preparing a celebratory meal for the five of them, animated with delight. Perhaps her culinary art is not rooted entirely in her fears after all.

Wen Qing wants to kiss her in the worst way. She cannot imagine a more ridiculously hopeless courtship than this.

Unfortunately, she doesn't have to; Wei Wuxian appears to be conducting one with Lan-er-gongzi. She's not convinced either of them have noticed.

The day after that, Wen Qing is expecting the treatment to awaken fear. She almost goes so far as to warn Yanli-mei's brothers, then concludes that their reactions will be deeply unhelpful. Yanli-mei herself, she does warn, which gets her a solemn nod, and, "promise me you'll finish it anyway?"

It's both an easy and a hard promise to give; she would be quite derelict in her duty to abandon this treatment now, but if Wen-Zongzhu were to arrive tomorrow and summon her back, she doubts any argument about her given word and the sect reputation would sway him. She tells Yanli-mei as much.

Not giving thought to the kidney's role as governor of desire may have been a mistake; Yanli-mei kisses her, enough steel in her spine that Wen Qing really internalises, for the first time, that this is the Violet Spider's daughter. Wen Qing is the one who has to pull away, to say, "Yanli-mei, you are reacting to the treatment, we cannot do this now."

There is all of her mother's fierceness in Yanli-mei's eyes when she says, "not now," and accedes.

. . .

They need written dispensation from the Lan healers again, the next day, if they are to continue the treatment past the hour of the pig. In spite of everything, it is easily granted; people - with the pointed exception of her betrothed, who has no idea how lucky he is - like Jiang Yanli, even the stiffest and most formal of the Lan.

Restoring the faint yin and lesser yang meridians of the hand brings emotional balance at last; Yanli-mei apologises to them all, quietly and unnecessarily, for her shifting moods.

The final pair, finishing with the liver at the hour of the ox, do not bring the anger associated with that organ, only an exhausted relief. They fall asleep on each others' shoulders, and Wen Qing suspects it is night-rat Wei Wuxian who covers them with a blanket.

. . .

"It's hard to believe it's real," Yanli-mei admits. "There were so many promises, when I was younger, and then I just - gave up hoping."

The extraordinary meridians do not seem to be afflicted with the same trouble. The three seas ebb and flow in their proper courses. It is likely that Yanli-mei would never have had any particular difficulty in conceiving and carrying a child.

When she mentions that a Jin midwife told her as much, Wen Qing has to fight down a red wash of fury at Jin presumption, that they would dare -

- of course they would dare. Their first young master, betrothed to one known to be in poor health; of course they would think it their right to know. Jin-Zongzhu would want a fertile brood mare for his single legitimate son. When Wen-Zongzhu's vast plans come to fruition, she will not be sad to see that one brought low.

If only Wen-Zongzhu would be content to plunder the vast wealth of Jinlintai and let the rest of the cultivation world alone.

They have the summer, at least, and if Yanli-mei is suddenly immensely busy, throwing herself into the training she has so long neglected, well, not even haughty Jin girls will raise their eyebrows when one so recently restored to health continues to visit regularly with her physician.

[candm-brittany-2023]

The Barrage d’Arzal-Camoël is the largest estuary dam in Europe, built in 1970 by the Institution d'Aménagement de la Vilaine. It prevents the tides from rising up the Vilaine and it regulates the height of the river during the year, which makes it possible to achieve several objectives: limiting floods, creating a reservoir for drinking water and developing river tourism. The lock here is the last before the tidal estuary, the next lock is 50 miles up stream 3 miles south of Messac. That’s some reservoir.

There are 6 piers and therefore 5 gates. The huge hydraulic gates regulate the flow of the river.

To protect the drinking water resource, the salt water that gets in on the river side during floods is rejected on the sea side by an ingenious syphon.

The water must not be salty, not only for its potability but also for certain industries that need fresh water. It was therefore necessary to devise a method of keeping the salt water out. Salt water flows in when the water enters the lock, and in summer when the lock is busy, this happens quite a lot. So they needed to set up a salt water drainage system: this is the purpose of the syphon. The sea water that enters the river side is denser than fresh water: it stays deep. The engineers therefore designed a “pit trap”. Salt water collects there, and the syphon pipes can suck it up. Carried by a raft moored to a fixed position, probes automatically measure the level of salt in the water. If this rate is above a certain threshold, the syphon comes into operation only of course when the sea level is below the level of the river.

By blocking the sea, the dam also blocked the fish! The sea fish and shellfish had to go elsewhere, but the eels, the salmon, the shad, and the lampreys are great migrants, who come from very far to go up the Vilaine. Since 1995, the situation has been remedied and a pass has been arranged for them.

Les Civelles (eels) benefit from preferential treatment. They are poor swimmers, and to make them cross the dam, they have built inclined sections lined with brushes, on which they climb while crawling.