Ancient Peruvian Water-Harvesting System Could Lessen Modern Water Shortages
VOA News
June 30, 2019 12:00 PM Kerry Hensley (source)
Ancient Peruvian Water-Harvesting System Could Lessen Modern Water Shortages
祕魯古老的集水系統能夠緩解現代缺水問題
June 30, 2019 12:00 PM
Kerry Hensley
Sometimes, modern problems require ancient solutions.
A 1,400-year-old Peruvian water-diverting method could supply up to 40,000 Olympic-size swimming pools' worth of water to present-day Lima each year, according to new research published in Nature Sustainability.
It's one example of how indigenous methods could supplement existing modern infrastructure in water-scarce countries worldwide.
More than a billion people across the world face water scarcity. Artificial reservoirs store rainwater and runoff for use during drier times, but reservoirs are costly, require years to plan and can still fail to meet water needs. Just last week, the reservoirs in Chennai, India, ran nearly dry, forcing its 4 million residents to rely on government water tankers.
Peru's capital, Lima, depends on water from rivers high in the Andes. It takes only a few days for water to flow down to Lima, so when the dry season begins in the mountains, the water supply rapidly vanishes. The city suffers water deficit of 43 million cubic meters during the dry season, which it alleviates with modern infrastructure such as artificial reservoirs.
Artificial reservoirs aren't the only solution, however. Over a thousand years ago, indigenous people developed another way of dealing with water shortages. Boris Ochoa-Tocachi, a postdoctoral researcher at Imperial College London and lead author of the study, saw firsthand one of the last remaining pre-Inca water-harvesting systems in the small highland community of Huamantanga, Peru.
Water diverted, delayed
The 1,400-year-old system is designed to increase the water supply during the dry season by diverting and delaying water as it travels down from the mountains. This nature-based "green" infrastructure consists of stone canals that guide water from its source to a network of earthen canals, ponds, springs and rocky hillsides, which encourage water to seep into the ground. It then slowly trickles downhill through the soil and resurfaces in streams near the community.
Ideally, the system should be able to increase the water's travel time from days to months in order to provide water throughout the dry season, "but there was no evidence at all to quantify what is the water volume that they can harvest from these practices, or really if the practices were actually increasing the yields of these springs that they used during the dry season," said Ochoa-Tocachi.
To assess the system's capabilities, the researchers measured how much it slowed the flow of water by injecting a dye tracer high upstream and noting when it resurfaced downstream. The water started to emerge two weeks later and continued flowing for eight months — a huge improvement over the hours or days it would normally take.
"I think probably the most exciting result is that we actually confirmed that this system works," Ochoa-Tocachi added. "It's not only trusting that, yeah, we know that there are traditional practices, we know that indigenous knowledge is very useful. I think that we proved that it is still relevant today. It is still a tool that we can use and we can replicate to solve modern problems."
Considerable increase in supply
The researchers next considered how implementing a scaled-up version of the system could benefit Lima. Combining what they learned from the existing setup in Huamantanga with the physical characteristics of Lima's surroundings, they estimated that the system could increase Lima's dry-season water supply by 7.5% on average, and up to 33% at the beginning of the dry season. This amounts to nearly 100 million cubic meters of water per year — the equivalent of 40,000 Olympic-size swimming pools.
Todd Gartner, director of the World Resources Institute Natural Infrastructure for Water project, noted that this study "takes what we often just talk about — that 'green [infrastructure] is as good as grey' — and it puts this into practice and does a lot of evaluation and monitoring and puts real numbers behind it."
Another benefit of the system is the cost. Ochoa-Tocachi estimated that building a series of canals similar to what exists in Huamantanga would cost 10 times less than building a reservoir of the same volume. He also noted that many highland societies elsewhere in the world have developed ways of diverting and delaying water in the past and could implement them today to supplement their more expensive modern counterparts.
"I think there is a lot of potential in revaluing these water-harvesting practices that have a very long history," Ochoa-Tocachi said. "There are a lot of these practices that still now could be rescued and could be replicated, even though probably the actual mechanics or the actual process is different than the one that we studied. But the concept of using indigenous knowledge for solving modern engineering problems, I think that is probably very valuable today."
現代面臨的問題有時需要仰賴先人的智慧。
近日一項在「自然永續」期刊（Nature Sustainability）發表的新研究顯示，具有 1400 年歷史的祕魯(Peruvian)水源分流(divert)法能夠提供現今(present-day)利馬市（Lima）的生活用水，且每年供應量可達 4 萬個奧林匹克（Olympic）標準泳池的用水量。
這個實例說明了在地原始的(indigenous)方法如何能夠彌補(supplement)全球缺水(water-scarce)國家現有基礎建設(infrastructure)的不足。
全球超過 10 億人面臨用水短缺(scarcity)的問題。人造水庫(reservoir)可貯存雨水和逕流(runoff)，提供旱季時期使用，不過水庫建造費用昂貴(costly)，計畫需時多年，而且很可能竣工後仍無法滿足供水需求。就在上週（編按：2019 年 6 月 16 日至 6 月 22 日），印度（India）清奈市（Chennai）的水庫幾乎乾涸見底，迫使 400 萬居民必須倚賴政府的水罐車(water tanker)供水。
祕魯（Peru）首都利馬市的水源來自於高處的河川，這些河川位於安地斯山脈（the Andes）。河水僅需幾天的時間就能流至利馬市，因此每逢山區乾旱期，水量供給很快就消失(vanish)殆盡。利馬市在乾旱期所面臨的用水不足(deficit)可達 4300 萬立方公尺，而現代化的基礎建設如人造水庫則緩解(alleviate)了缺水情況。
然而，人造水庫並非唯一的解決辦法。當地的原住民於 1000 多年前開發出另一種處理水源短缺(shortage)問題的方法。鮑里斯．奧喬亞多可奇（Boris Ochoa-Tocachi）是英國倫敦帝國學院（Imperial College London）的博士後研究員，也是這項研究的主持人。他在祕魯瓦曼坦加區（Huamantanga）高地(highland)的小型社區裡親身(firsthand)見到前印加時期（pre-Inca）遺留下來的集水系統（water-harvesting system），也是目前僅存的系統之一。
分流改道，延緩流速
這座集水系統具有 1400 年歷史，其目的在於藉由山區河流改道並減緩流速的方式增加乾旱期的供水量。這個以自然為本的「綠色」基礎建設包含了石造渠道，可以引導水流從源頭進入由土製(earthen)河渠、池塘、泉水和崎嶇山坡(hillside)組成的網絡，目的在於促進水流滲入(seep into . . .)地底，並能在土壤裡朝下坡(downhill)緩緩流動(trickle)，接著流入村莊附近的溪流，再次回到地表(resurface)上。
就理想上而言，這系統應該能讓水源從原本僅需幾天的流動時間增加至幾個月，以提高整個乾旱期的供水量，「不過目前還沒有足夠的資訊來推測、確定當年以這種方式所收集(harvest)到的水量有多少(quantify . . .)，也無法確認乾旱期的泉水量是否因此增加。」奧喬亞多可奇解釋道。
研究人員從上游(upstream)注入染料追蹤劑(dye tracer)，並在下游(downstream)觀測水流會在何時重回地面，藉此測量集水系統減緩流速的程度以評估其集水功能(capability)。水流於兩週後重新出現在地表上，並且持續流動達 8 個月之久，這和過往僅持續幾小時或幾天的流量相比，可說是長足的進步。
「我認為最令人興奮的結果應該是確認集水系統可以順利運作。」奧喬亞多可奇補充說明。「我們不僅了解傳統的集水方法，同時明白在地遠古的知識非常有用。而且經過證實，這些知識還能用在現代，讓我們可以如法炮製(replicate)作為解決問題的工具。」
供水量明顯增加
研究人員緊接著思考該如何運用比例加大的(scaled-up)集水系統才有益於利馬市的供水。他們把從瓦曼坦加區現有系統結構中所學到的知識與利馬市周圍的環境特性結合起來，估算出集水系統能讓利馬市乾旱期的供水量平均增加 7.5 %，且初期供水量可增加至 33%。如此一來，每年增水量共計(amount to . . .)約 1 億立方公尺，等同(equivalent)於 4 萬個奧林匹克標準泳池的水量。
陶德．高德納（Todd Gartner）指出，這項有關集水系統的研究，不僅考量了平日經常探討的「綠色與灰色兩種基礎建設一樣重要」的論點，更透過各種評估、監測(monitor)並呈現測量數據的方式，把論點付諸實行。他是世界資源研究中心（World Resources Institute）「水資源自然基礎建設（Natural Infrastructure for Water）」計畫的主持人。
〔編按："green infrastructure"「綠色基礎建設」指具有控制暴風雨、降低洪水災害及改善水質等功能的天然區域，例如公園、濕地或森林保護區。"grey infrastructure"「灰色基礎建設」則指人為的工程設施，多數由水泥鋼筋建造而成。兩者差異請參考 Green vs. Gray Infrastructure: When Nature Is Better than Concrete 一文之說明。〕
此外，運用集水系統還能帶來成本上的效益。奧喬亞多可奇估計，建造一系列與瓦曼坦加區相似的河渠比起建造相同容量的水庫，將可節省 10 倍的花費。他進一步談到，世界各地的許多高地社區以往也曾發展出各種分流改道並且延緩流速的方法，這些方法目前仍可用來彌補作用相同(counterpart)但較為昂貴的現代設施（如水庫）的不足。
「在我看來，重新評估(revalue)歷史悠久的集水方法能創造出許多可能的用途。」奧喬亞多可奇表示。「以往的很多作法都可以恢復並且重複運用，儘管實際的運作方式(the mechanics)或過程可能和我們所研究的不盡相同。不過，就目前來說，運用在地遠古的知識解決現代工程的問題應該很有用。」
Language Notes
divert [dɪ`vɝt] / [daɪ`vɝt] / [də`vɝt] (v) 使改變方向，使轉向；使改道
* 注意本字重音在第 2 音節；另有「將 . . . . . . 用於其他目的；改變 . . . . . . 的用途」或「分散，轉移（注意力）」等意
indigenous [ɪn`dɪdʒənəs] / [ɪn`dɪdʒɪnəs] (a) 當地的；本土的，土生土長的；土著的
* 注意本字重音在第 2 音節；也有「生而俱有的，固有的，內在的」之意
supplement [`sʌplə͵ment] / [`sʌplɪ͵ment] / [`sʌplə͵mɛnt] (v) 增加，補充，增補
* 本字亦可作名詞（發音為 [`sʌpləmənt] / [`sʌplɪmənt]），意指「補充物，增補物」、「（雜誌或報紙的）增刊，副刊」或「（書的）附錄，補編，補遺」
infrastructure [`ɪnfrə͵strʌktʃɚ] (n) 基礎建設；公共建設（如鐵路、公路、下水道等）
scarcity [`skersəti] / [`skɛrsəti] / [`skɛrsətɪ] (n) 缺乏；不足；短缺；蕭條（時期）
* scarce [skers] / [skɛrs] (a) 缺乏的；不足的；難得的，稀有的，罕見的
reservoir [`rezɚ͵vwɑr] / [`rezɚ͵vɔr] / [`rɛzɚ͵vɔr] (n) 水庫；蓄水池（或槽）；貯存器
* 本字也常指「儲備；儲藏；寶庫」
runoff [`rʌn͵ɔf] (n) 逕流；流量
* 本字另有「決賽；決選投票」之意
deficit [`defəsɪt] / [`defɪsɪt] / [`dɛfɪsɪt] (n) 不足額；赤字；逆差；虧損
* 建議可由字首 "de-"「減少；低下」幫助記憶與理解本字
alleviate [ə`livi͵eɪt] / [ə`livɪ͵eɪt] / [ə`livɪ͵et] (v) 減輕；緩和，緩解
* 注意本字重音在第 2 音節
seep [sip] (v) 滲出；滲漏
* 本字後常接 "out of . . ."、"into . . ." 等介系詞片語，例如：". . . seep out of farmland . . ."「. . . . . . 從農田滲出 . . . . . .」；". . . seep into the water supply . . ."「. . . . . . 滲入供水系統 . . . . . .」
trickle [`trɪkl̩] (v) 從 . . . . . . 向下滴（或淌）
downhill [͵daʊn`hɪl] (adv) 向山下，朝坡下；下山地，下坡地
* 注意本字重音在第 2 音節；也可作形容詞，指「向山下，朝坡下；下山的，下坡的」
resurface [͵ri`sɝfɪs] (v) 再次浮出；再次露出水面
* 本字由字首 "re-"「再；重新」和動詞 "surface"「浮出水面」組成；注意重音在第 2 音節；另有「（失竊、失蹤或缺席後）再露面，重新出現」及「（記憶）浮現，喚起，再次出現」等意
quantify[`kwɑntə͵faɪ] / [`kwɑntɪ͵faɪ] (v) 確定 . . . . . . 的大小（或數量）；以數量表示；使量化
* quantity [`kwɑntəti] / [`kwɑntətɪ] (n)（尤指可測量或確定的）量，數量，分量
harvest [`hɑrvɪst] / [`hɑrvəst] (v) 獲得，得到；收割，收穫，捕獲
* 本字亦可指「採集（細胞或器官以作醫學用途）」；也常作名詞，意即「收穫時節；收割，收穫；收成」
capability [͵keɪpə`bɪləti] / [͵kepə`bɪlətɪ] (n) 功能，性能；耐受力
* 本字由形容詞 "capable"「有能力的；熟練的；能幹的」和表示「性質、狀態」的抽象名詞字尾 "-ity" 組成；注意重音在第 3 音節；另常見意思為「能力；才能；水準」
upstream[͵ʌp`strim] / [`ʌp͵strim] (adv) 在上游；向上游地；逆流地
* 注意本字重音可在第 1 或第 2 音節；亦常指「在（某過程或事件的）前階段」；也可作形容詞，意即「在上游的；向上游的；逆流的」
downstream [͵daʊn`strim] / [`daʊn͵strim] (adv) 在下游；向下游地；順流地
* 注意本字重音可在第 1 或第 2 音節；也常指「後階段地」；亦可作形容詞，即「在下游的； 向下游的；順流的」
replicate [`replɪ͵keɪt] / [`rɛplɪ͵keɪt] / [`rɛplɪ͵ket] (v) 使複現；重複；複製
* 建議可由字首 "re-"「再；重新」幫助記憶與理解本字
amount to something (v phr) 合計 . . . . . .；共計 . . . . . .
* amount [ə`maʊnt] (n)（尤指不可數事物的）數量；數額；量；總數
equivalent [ɪ`kwɪvələnt] (n) 等值；相等；等同
* 注意本字重音在第 2 音節；也常作形容詞，意即「等值的；相等的；等同的」
monitor [`mɑnətɚ] / [`mɑnɪtɚ] (v) 監控；監測；監視，密切注視
* 本字亦可作名詞，指「監督員，核查員」、「監控器，監測器」或「顯示器，螢幕」
counterpart [`kaʊntɚ͵pɑrt] (n)（與不同地方或組織的人或物）作用相同者，相對應者
the mechanics (n phr) 例行方法，運作方式
* mechanics [mə`kænɪks] (n) 力學；機械學；技術性的部分；技術；技巧
Check your vocabulary!
Fill in the blanks with a word or phrase from the list above. Make necessary changes. After you finish, highlight the blanks to reveal the hidden answers.
1. Marias opens the piece by talking about how some phrases just don't have a similar equivalent in other languages.
2. It is often assumed that the resource can be harvested up to a certain level without depleting it.
3. Researchers studying flow in collapsible tubes have examined the mechanics of how blood gets pumped all the way up a giraffe's neck to its brain.
4. An exposed brick chimney retains the fire's warmth for hours, supplementing the home's central, water-based heating system.
5. Many conditions associated with old age can be treated and alleviated, if not cured.
6. Soybeans are indigenous to China and have long been a part of that country's diet.
7. The experiences the baby has in the first few years of their life determines the intellectual capability of the child.
8. The government claimed they were doing a good job of reducing the country's trade deficit and balancing the budget.
9. By 1920 state and private interests had carved four massive canals to divert water directly into the Atlantic Ocean and create dry farmland.
10. Eighteenth-century urban dwellers lived in much worse conditions than their modern counterparts.
11. Systems theory suggests that a closed loop of activity, left undisturbed, will replicate itself over and over.
12. An independence based upon an abundance of goodwill may be found even where there are scarcities in power resources.
編譯：外語教學暨資源中心 編輯小組
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