不论河流、湖泊还是海洋，水都是中国人文化想象的重要地标。“五湖四海”至今仍然是最常用的成语，表示“来自全国各地”之意。China’s rivers, lakes and seas are an important part of the country’s cultural geography, with the phrase “five lakes, four seas” meaning something akin to “from all over the country”.
然而这个文化符号在现实中却面临着深重的危机——中国人均淡水资源不仅排在全世界最低的行列，而且还在继续减少。与此同时，仅有的淡水资源还面临着污染威胁：化肥使用量继续高居世界第一，纺织、造纸等水污染严重的工业也规模巨大，工农业水足迹居高不下。But most of the country's lakes are in a state of crisis. China has a much smaller freshwater resource by population than many other nations, and those resources are both shrinking and threatened by pollution. Not only is China the world’s largest user of fertilizers, its water-polluting industries such as textiles and paper-making are huge, and both agriculture and industry have enormous water footprints.
值世界水日之际，中外对话为您盘点中国五个标志性湖泊的现状。需要注意的是，旧的“五湖”概念仅指几百年前东、中部地区的几个淡水湖，我们的盘点则将视野扩大到整个中国内地。Here, we include a couple of China’s traditional “five lakes” in the central and eastern parts of the country, but also include others that may not have the same cultural importance but which remain valuable ecosystems.
鄱阳湖——建闸还是不建
尽管被称为中国第一大淡水湖，鄱阳湖的面积却没有一个固定的数字。这个通向长江的巨大浅湖每年都会随着长江水位的升降经历急剧的水位变化，湖泊面积在3000多平方公里和100多平方公里之间摇摆，有着 “洪水一片、枯水一线”的说法。
枯水季节的鄱阳湖为远道而来的候鸟提供了食物补给及栖息落脚之地，每年秋冬无数候鸟从西伯利亚长途跋涉来此过冬。
近10年来鄱阳湖连续出现枯水时间提前、枯水期延长、水位超低等现象。极端情况下，湖边的居民区甚至遭到停水。除了气候变化，世界最大水电站三峡大坝对鄱阳湖水位的影响也备受争议。
江西省鄱阳湖水利枢纽建设办公室打算在长江和鄱阳湖间修建一道水闸以缓解这一问题。但反对声认为，隔断长江和鄱阳湖不仅阻碍鱼类洄游，冬季过高的水位也令候鸟难以适应，造成生态灾难。此外，减少鄱阳湖输往长江的水量又会不会影响下游诸省市的水安全呢？目前看来这场争议还将继续下去。
Poyang Lake – to dam or not to dam
Despite being known as China’s largest freshwater lake, Poyang has no fixed size. The lake is huge, shallow and connected to the Yangtze, which means that every year its size fluctuates in line with the height of the river, shifting wildly from between 3,000 to only 100 square kilometres. For this reason it is known for becoming a wide expanse of clear water when in flood but little more than a river in the dry season.
But though Poyang shrinks during the dry season, it still provides a crucial habitat for migrating birds, which arrive here in autumn from Siberia to rest over the winter.
Yet for a decade now, Poyang has been experiencing earlier and longer dry seasons, and unusually low water levels. In extreme cases the locals have seen water supplies cut off entirely. Climate change is one reason, but the role of the Three Gorges Dam, the world’s biggest hydropower project, has also come in for scrutiny.
The office in charge of the lake’s water management system plans to build a barrier between the Yangtze and Poyang Lake to address the problem. But opponents say this will block migrating fish, and higher water levels will cause problems for the birds – resulting in ecological disaster. There is also a question over whether or not retaining more water in the lake will affect water security for cities downstream. The debate looks set to continue.
青海湖——第一大湖触底反弹
青海湖位于青藏高原东北部，是中国最大的咸水湖泊，也是第一大湖。和其他湖泊正面临水域面积缩小不同的是，青海湖近年的水位年年走高，似乎已走出低谷。
青海省地理监测部门从1974年开始监测其湖区面积，发现从当年到2004年，湖水面积缩小了253平方公里，为1974年面积的5.67%。10年前，中外对话曾对青海湖的连年萎缩表示担忧，但出人意料的是，青海湖面积从2005年开始逐年回升，2016年已经几乎回升到42年前的巅峰状态。
2017年2月，青海省地理普查显示，青海湖流域地区自然生态环境维护良好。青海湖国家级自然保护区管理局认为，除了退耕还林还草、植被修复等人为养护因素，气候变化导致的区域降水和冰川融水增加也是青海湖触底反弹的重要原因。威胁着诸多低海拔岛屿和海岸命运的气候变化竟成为中国第一大湖的利好因素，这实在令人五味杂陈。
Qinghai Lake – back from rock bottom
Qinghai Lake is a saltwater lake situated in the north-east of the Qinghai-Tibetan Plateau, and is China’s largest. But unlike other lakes that are shrinking, Qinghai seems to be recovering, with water levels increasing in recent years.
The provincial authorities have monitored the lake area since 1974, finding that in 2005 it had shrunk by 253 square kilometres, to 5.67% of its size in 1974. chinadialogue expressed concern about the risk to the lake a decade ago. But since 2005 the lake has, unexpectedly, been recovering. By 2016 it was almost back to its 1974 size, the largest recorded.
In February 2017 a provincial survey found the environment of the Qinghai Lake basin was well protected. The management bureau for the Qinghai Lake National Nature Reserve says that alongside interventions, such as returning farmland to forests and pastures and restoration of vegetation, another important factor is increased precipitation and glacier melt resulting from climate change. It’s ironic that while changing weather patterns are threatening low-lying islands and coastal areas, China’s largest lake is actually benefiting.
乌梁素海——靠农业维系的湖泊
这个位于内蒙古，栖息着200多种鸟类的美丽湖泊养育了世界上同一纬度最大的湿地。严格说来，乌梁素海是一个由人类活动维系的半天然半人工湖——它由黄河改道形成。但如今80%的湖水来自于周边农田排出的灌溉水，仅有少量来自降水。
从1965年到1975年，当地人民用十年时间在黄河、农田和乌梁素海之间修建了一个现代化的排水体系，使得灌溉水可以快速排入乌梁素海，好让湖中的植物和微生物吸收水中残留的化肥，“净化”后的水再从湖泊的另一个出口流回黄河。
这一整套从黄河引水，从乌梁素海泄水的灌渠网络使乌梁素海附近的河套平原地区成为中国北方最重要的农业生产基地之一。而农业退水也挽救了乌梁素海本该干涸的宿命，使其成为鸟类天堂和旅游胜地。
但这个看似完美的系统如今却处于失效边缘。专家指出，中国的化肥施用量在过去40年间增长了55倍，而如今乌梁素海已无力净化流入其中的化肥残留。近十年来，每年夏季湖水都面临着富营养化导致的黄藻爆发风险，而覆盖水面的黄藻会加剧水质恶化，从而影响从鱼到鸟的整个生态系统。
Ulunsuhai Nur
Situated in Inner Mongolia, Ulunsuhai Nur is home to 200 types of bird and is the highest wetland at this latitude. Strictly speaking, the lake is manmade, and was formed by efforts to redirect water from the Yellow River. Today, 80% of its water is directed through agricultural irrigation systems nearby, with the rest coming from rainfall.
From 1965 to 1975 local people constructed a modern drainage system between the Yellow River, farmland and Ulunsuhai Nur, to ensure water from irrigation would flow quickly into the lake where vegetation and microorganisms would break down fertilizer run-off. The “purified” water is then returned to the Yellow River.
That system of irrigation and drainage made the plains around Ulunsuhai Nur one of northern China’s most important agricultural regions, while the recovery of water from agriculture made the lake – which should be arid – a paradise for birds and a tourist hot spot.
But the system is today on the brink of failure. Experts point out that fertilizer use in China has increased 55-fold in 40 years, and Ulunsuhai Nur can no longer cope. For about ten years the lake has seen algal blooms during some summers resulting from eutrophication. This has worsened the water quality and affected the entire ecosystem, from birds to fish.
罗布泊——记忆中的湖泊
从空中俯瞰宛如一只巨耳的罗布泊是新疆的一个已经干涸的大湖。1920年代，罗布泊面积据测算还有3000平方公里，是北京城区面积的两倍多；而迟至1959年还有科考人员在罗布泊上泛舟。人们至今无法准确断定罗布泊干涸的原因和时间，只知道其所在的地区极其干旱，一旦上游河水断流，仅仅3、4米深的罗布泊就可以在几年时间内彻底干涸。
这片已经消失的水域似乎总是与传奇相伴。20世纪早期的传奇瑞典历险家斯文·赫定（Sven Anders Hedin）在一片戈壁中发现了它，后来的考古学家依据挖掘出的文物断定罗布泊流域曾是古“丝绸之路”上一片重要的绿洲。更具传奇色彩的是，1980年和1996年，两位中国著名的探险家彭加木和余纯顺先后失踪于罗布泊遗址，尸骨至今下落不明。
现在的罗布泊已成为一望无际的戈壁滩，夏季高温时天空不见一只鸟，被称为死亡之海。
Lop Nur – the Sea of Death
Look down from the air and you can see the ear-like shape of Lop Nur, once a large lake but now dried up. In the 1920s it was estimated to be 3,000 square kilometres in size – twice as large as Beijing today. In 1959, it was still possible to sail a boat on it. It’s unclear when the lake dried up exactly, but the region is incredibly arid and once the rivers stopped flowing, Lop Nur, which was only three or four metres deep, may have dried up in a matter of years.
The lake has always had a legendary quality. Sven Anders Hedin, a Swedish explorer in the early 20th century, “discovered” it while travelling through the desert. Archaeologists later excavated relics and determined that it would have been an important oasis and stop on the Silk Road. It’s also claimed the lives of a number of explorers, including two famous Chinese adventurers, Peng Jiamu and Yu Chunshun who went missing around Lop Nur in 1980 and 1996.
Lop Nur is now just another expanse of desert. In summer it reaches extreme temperatures and not a bird is to be seen in the sky. It is now known as the Sea of Death.
太湖——耗千亿元治理的湖泊
“太湖美，美就美在太湖水，水上有白帆哪，水底鱼虾肥……”，《太湖美》是中国传唱最广的一首赞美湖泊的歌曲。但在2007年，这个美好的画面被彻底打碎。当年，太湖蓝藻暴发，水质恶劣且臭不可闻，湖边的无锡市民1周用不上干净自来水的新闻传遍媒体。超市、商场桶装水被抢购一空。
太湖位于中国经济发达省份江苏省和浙江省的交界处。太湖流域以全国0.4%的国土面积创造着约占全国1/8的国民生产总值。太湖流域城市化水平居全国之首，但与此同时该地区单位面积排放的污染物量也是全国的9倍。排放进太湖的污染物不断累积致使水体富营养化，最后爆发蓝藻危机。
太湖的污染给当地政府造成了巨大代价。截至2014年，各级政府已经为太湖流域污染治理累计投资至少960亿元，并还将投入约1164亿。
但与此同时，太湖的治理也走出了新的道路，成为中国水污染治理的榜样：太湖流域是全国第一个试点排污权交易的流域; 而江苏也是全国最早建立企业环境信用评价体系的省份之一。
近年来，太湖流域水质总体有所改善，但蓝藻水华暴发的威胁仍未去除。
Lake Tai – the 100 billion yuan clean-up
The beauty of Lake Tai has long been praised in Chinese poems and songs. But by 2007 that beauty was all but gone. An algal bloom, poor water quality and a foul smell left residents of nearby Wuxi without clean drinking water for a week, resulting in widespread media coverage and panic-buying of bottled water.
Lake Tai lies between Jiangsu and Zhejiang, two of China’s most developed provinces. The Lake Tai basin covers 0.4% of China’s land mass, yet accounts for 8% of its GDP. The area is China’s most urbanised – and produces nine times more pollutants per unit of area than the national average. The pollutants pouring into the lake resulted in eutrophication, and then algal blooms.
The costs to local government were huge. As of 2014, government at all levels had spent a total of 96 billion yuan (US$14 billion) cleaning the lake, with another 116.4 billion (US$17 billion) to come.
But the approach to cleaning up the lake has also established a new model in China for similar problems elsewhere, making it possible to trade the right to release waste water. Jiangsu was also one of the first provinces to set up an environmental credit rating system for businesses.
