河流是地球的生命動脈，它哺育了生命，孕育了文化，灌溉了人類文明，帶給人類諸多享受和樂趣。但如今有很多河流面臨各種威脅，往昔的自然之美瀕臨破壞與消逝。下面就隨本文一起去探索世界三大瀕危河流，讓我們投入它們的懷抱，盡情感受它們酣暢淋漓的美，更喚醒我們內(nèi)心保護它們的本能。

The fate that a scheduled dam project forever disrupts the flow or something similar， has befallen1） most major river systems on earth—and though we often lament2） their loss， we continue to dam， divert or otherwise mar3） or destroy our last remaining wild rivers. Even a dammed river can remain an enduring symbol of its landscape， as do the extensively developed Mississippi and the Nile. But such hydro4）-developed rivers may face other threats， especially overuse of their waters， which can eliminate a river entirely. Following are three of the most beautiful but most threatened rivers worth seeing while they still flow.

The Danube

Length： 1776 miles

Discharge： 229，000 cubic feet per second

Main threat： pollution， development of adjacent lands and development of the river as a shipping channel

Europe's second-largest river after the Volga， the Danube is remarkable for the many cultures it touches， and the many borders it crosses， en route5） from the Alps to the Black Sea. The Danube has been characterized as dividing， uniting， and defining Central Europe. The river's source is in the Black Forest of Germany， while it gains much of its volume6） from the Alps. It's a fine way for a river to begin—but things get complicated for the Danube the more countries it touches. Government conservation efforts may be hampered7） by the Danube's very diversity—for the river， which the World Wildlife Fund has called the "most international river in the world"， literally absorbs the direct runoff8） of 18 countries—including the war-scarred Balkan nations and the industrial landscapes of parts of Poland， Germany， and Hungary. Named in 2007 as one of the ten most threatened rivers in the world， the Danube offers a variety of beautiful trip opportunities. People may cycle tour the length of the river， traveling as they go either through or near Germany， Austria， the Czech Republic， Slovakia， Romania， and many more nations. Or they may walk the gentle valley of the Danube， among vineyards and orchards， past Transylvanian castles， and through great cities like Belgrade， Budapest， and Vienna. Or they may explore this great river by boat.

The Murray

Length： 1476 miles

Discharge： 27，086 cubic feet per second

Main threat： dwindling9） fish species and overuse of waterendprint

Australia's longest and most massive river， the Murray flows from the Australian Alps southeastward and into the Southern Ocean near the city of Adelaide. Like nearly any river in a dry and thirsty land， the Murray is a critical life source—both for native fish and wildlife， like the barramundi， dolphin， and the man-size Murray cod， and for local agriculture， including southern Australia's famed wine industry. Though dams and locks cross the river at numerous places， the Murray is nonetheless a popular destination for paddlers10）—some of whom may float the entire river. The Murray is a gentle waterway， broad and slow for much of its length， and is relatively welcoming to novice11） river paddlers—though it does have a few whitewater12） sections. The future of the Murray is in question. The river's flow is naturally erratic13）， and in dry years it has failed entirely to reach its end. As demand for the Murray's water grows， climate change is expected to become a major stressor on this threatened river.

The Mackenzie

Length： 2637 miles to head of Finlay River

Discharge： 349，968 cubic feet per second

Main threat： possible hydroelectric development

The Mackenzie drainage system receives the precipitation14） from almost 20 percent of Canada's land area and abuts15） that of the Yukon River， the Fraser， the Columbia， and the Churchill. Measured from the head of the Finlay River， the Mackenzie is one of the longest rivers in the world. However， many people—and canoeists—discuss the Mackenzie only in terms of its main branch， an un-dammed 1000-mile run that flows north out of the massive Great Slave Lake. This river's remote location has made it largely immune to many of the threats that have affected other great rivers—and almost certainly， the Mackenzie is one river system that will never dry up at the doings of people. And while the Mackenzie itself remains un-dammed， several hydroelectric projects have been built on its tributaries16） and there is growing interest in tapping into the energy of the Mackenzie's main stem. Still， the Mackenzie drainage offers among the greatest wilderness experiences left on earth. Probably the best option is to let the river do the work and float downstream via canoe， raft， or kayak. Where to start is the question. Some adventurers may start on the South Nahanni， while others may tackle the Mackenzie beginning at Great Slave Lake， a roughly month-long trip of probable bear encounters， wild camping， and excellent fly fishing17）. Because it may someday be hydro-developed， the Mackenzie has been named among Canada's most threatened waterways. For now， though， this Arctic giant remains one of the world's freest， cleanest， wildest rivers.endprint

水流被規(guī)劃好的筑壩工程永久阻斷的命運或諸如此類的事已經(jīng)降臨于地球上大部分主要的水系。而且雖然我們常常為它們的損失感到惋惜，但我們?nèi)岳^續(xù)筑壩，使河流改道或者用別的方式損毀或破壞我們最后僅剩的那些自然河流。即使筑了壩的河流可以繼續(xù)做該地區(qū)永久的標志性景觀，就像被廣泛開發(fā)的密西西比河和尼羅河那樣，但這些被開發(fā)來發(fā)電的河流可能面臨其他威脅，尤其是河水的過度利用——那可以徹底毀滅一條河。下面是三條最美麗但也最瀕危的河流，值得我們趁它們?nèi)栽诒剂鲿r去一飽眼福。

多瑙河

長度：1776英里

流量：229，000立方英尺/秒

主要威脅：污染、沿岸開發(fā)、河流被開發(fā)用作船運河道

作為僅次于伏爾加河的歐洲第二大河流，多瑙河一路從阿爾卑斯山脈流至黑海，以其觸及文化之廣、跨越國界之多而聞名于世。多瑙河一直具有分割、連接和界定中歐地區(qū)的特征。多瑙河發(fā)源于德國的黑林山，不過其大部分水量卻來自阿爾卑斯山。對于一條河來說，這是個很好的發(fā)源方式，但多瑙河因為流經(jīng)國家較多，情況變得復(fù)雜起來。政府做保護工作付出的努力可能會因多瑙河的這種多樣性而受阻礙，因為被世界野生動植物基金會稱為“世界上最國際化的河流”的多瑙河確實吸納了18個國家的地面徑流——這些國家中有飽受戰(zhàn)爭創(chuàng)傷的巴爾干半島各國、波蘭的部分工業(yè)發(fā)達地區(qū)、德國和匈牙利。多瑙河曾在2007年被列為世界十大瀕危河流之一。它給游人提供了各種美好旅程的機會。人們可以騎車沿河游覽，橫穿德國、奧地利、捷克、斯洛伐克、羅馬尼亞還有更多國家，或是在這些國家附近游覽；也可以徜徉在多瑙河溫和的河谷，漫步于一個個葡萄莊園和果園，觀賞沿途的特蘭西瓦尼亞城堡，穿過諸如貝爾格萊德、布達佩斯、維也納這樣的名城；或者還可以乘船探索這條美麗的河流。

墨累河

長度：1476英里

流量：27，086立方英尺/秒

主要威脅：魚的種類不斷減少、河水過度利用

墨累河是澳大利亞最長、流域面積最廣的河流，發(fā)源于澳大利亞阿爾卑斯山的東南部，在阿德萊德市附近注入南大洋。像幾乎任何一條流經(jīng)干旱少雨的土地的河一樣，墨累河是至關(guān)重要的生命之源，不論是對原生魚類和野生動物（如澳洲肺魚、海豚、成人大小的墨累鱈魚），還是對包括南澳地區(qū)著名的紅酒業(yè)在內(nèi)的當?shù)剞r(nóng)業(yè)。雖然河上很多地方都橫跨著水壩和水閘，但墨累河仍然是漂流者們很喜歡的去處，其中有些人可能會在整個河段漂流。墨累河是一條平緩的航道，大部分河段水面寬闊、水流緩慢，相對來說更受漂流新手們的歡迎，雖然它確實有幾個急流河段。墨累河的未來尚不明確。河水水流本身就不穩(wěn)定，在干旱的年份曾徹底斷流。隨著人們對墨累河用水需求的增加，氣候變化可能會成為這條瀕危河流最大的威脅。

馬更些河

長度：2637英里（從芬利河源頭算起）

流量：349，968立方英尺/秒

主要威脅：潛在的水電開發(fā)

馬更些河水系吸納了加拿大陸地近20%的降水量，還毗鄰育空河、弗雷澤河、哥倫比亞河和丘吉爾河水系。從芬利河源頭算起，馬更些河是世界上最長的河流之一。然而，許多人——還有獨木舟愛好者——談?wù)撈瘃R更些河時只是指它的干流——從巨大的大奴湖向北奔流1000英里的無水壩河段。馬更些河地處偏遠，這使其在很大程度上免受很多其他一些大河業(yè)已遭受的威脅。而且我們幾乎可以肯定，馬更些河是一個永遠不會因為人類活動而枯竭的水系。雖然馬更些河本身還沒有被筑壩，但它的支流上已經(jīng)建了一些水力發(fā)電工程，人們對挖掘其干流能源的興趣也在增長。不過，目前馬更些河流域仍能為游客們提供地球上最令人驚嘆的自然體驗之一?；蛟S最好的選擇就是讓河水來當差，你只管乘著獨木舟、竹筏或橡皮艇順流而下。從哪里開始游覽才是你要關(guān)心的問題。有些探險者可能會從南納漢尼河開始，其他人可能會從大奴湖開始游覽馬更些河——在這約一個月的旅程里，你可能會遇到熊，可能要在野外露營，或是來次非凡的飛釣。由于這里有朝一日可能會興建水力發(fā)電工程，馬更些河已經(jīng)被列為加拿大最瀕危的水道之一。不過目前看來，這條流經(jīng)北極圈的長河仍是世界上最自由、最干凈、最富自然氣息的河流之一。endprint