陈富强

丽水通济堰，建成已逾1500年，入选世界灌溉工程遗产。通济堰上建有一座立体交叉石函引水桥，俗称“三洞桥”。曾有一位名叫福田的日本人站在“三洞桥”上赞叹说：“当世界上尚无立交桥时，中国人已在这山乡建造了水的立交桥。”

南宋名臣范成大入处州（今浙江丽水），是乾道三年（公元1167年），距今逾850年。由此再上溯至南朝萧梁天监四年（公元505年），逾660年，两数相加，逾1500年。这是丽水通济堰的年龄。

梳理中国的水利设施，如果遗漏通济堰，通常是一个常识性错误。虽然我没有十分丰富的水利方面学识，但对于中国最著名的水利设施，我还是大致能说出一二。我研究电力多年，而水利总是和电力连在一起。水电一家，是近现代史上最明显不过的孪生双胞，密不可分，所谓无水不成电。当然，古代的水利设施，则更侧重于治水，比如新疆的坎尔井，成都的都江堰，丽水的通济堰。

但我确实犯了一个常识性的甚至是不可原谅的错误。多年以前，我参与《中国治水史诗》的创作，这部堪称中国治水百科全书的巨作，汇集了当代近百名作家的智慧。我主笔浙江篇。从大禹治水的传说写起，由鉴湖而至苏东坡疏浚西湖，再由京杭大运河南端而循钱塘江源头顺流而下，写到了千岛湖的形成，富春江的山水。凡浙江水利，皆一一收录。但我居然将浙江重要的通济堰放在一边，在成文时，竟然遗忘了。直至书出版，我还没有意识到这个重大失误。

数月后，一封来自丽水的手写书信出现在我的案头。自从有了网络，我已经很少接触到类似书信。我展开一阅，居然读出一身冷汗。此信作者是丽水一位很有声望的老作家，名叫吴刚戟。吴老先生在信中指出，既然写浙江水利，怎么可以不写通济堰？我从吴老先生的字里行间，能感受到他的失望，甚至气愤。冷静思想，我在写作过程中，的确没有把通济堰列上重点，以至于在最后成稿时，将其遗漏。一方面是我缺乏对通济堰重要性的认识，另一方面，也可见自己治学的不够严谨。我当即给吴老先生回函，除了检讨，我也向他保证，会修订我主笔的浙江治水篇，尽可能弥补这个缺憾。

后来，虽然有关通济堰的内容，我作了增补，并且在发表和收录其他文本时，用的是完整篇章，但这个遗憾却一直压在我的心头，难以排解。且不说通济堰的历史可与都江堰媲美，仅世界上最早的拱形坝体这个记录，就足以说明通济堰在世界水利史上的不同凡响。国外最早的拱坝是西班牙人建于16世纪的爱尔其拱坝和意大利人建于1612年的邦达尔多拱坝，而始建于公元505年的通济堰比它们的历史要早1000多年。所以，后来通济堰能入选世界灌溉工程遗产，也变得理所当然。

在我主笔浙江治水篇10年后，我第一次见到通济堰真容。虽然稍晚了一些，但相比古堰1500年的历史，10年不过沧海一粟。

从石函引水桥，过文昌阁，向古堰行500米，即到通济堰坝体。石函引水桥是一座水上立交桥，建造的起因是距离古堰拱形大坝500米处有一条名为泉坑的山坑，其水横贯通济堰渠道，每遇山洪暴发就挟带大量沙砾和卵石冲泄而下，淤塞渠道，使堰水受阻，需经常疏通。面对如此水患，很久以来似乎没有很好的根除方法。直到北宋政和元年，时任知县王褆按邑人叶秉心的建议，在通济堰上建造了一座立体交叉石函引水桥，俗称“三洞桥”。引泉坑水从桥面上通过，进入瓯江，渠水从桥下穿流，两者互不相扰。由此避免了坑水的沙石堵塞堰渠，使渠水畅通无阻，不需年年疏导，真有“石函一成……五十年无工役之扰”的功效。可见当时设计、建筑水平已经十分高超。据称，曾有一位名叫福田的日本人站在“三洞桥”上赞叹说：“当世界上尚无立交桥时，中国人已在这山乡建造了水的立交桥”。

护堤的古樟群堪称通济堰一景。这些香樟树，树龄通常有数百年之久。其中一棵已枯死，但神奇的是，如果不经点拨，很难看出这棵古樟已无绿叶，因为在水渠的对岸，也有一棵同样古老的香樟，那棵树依旧枝繁叶茂，两树的枝叶在水渠上空相触，茂密的绿叶覆盖住枯树的枝叶，倘若不加细辨，很难区分。这些樟树苍劲挺拔，遮天盖地，扎根于泥土之下，盘根错节，为护堰尽毕生之力。而樟树散发出来的特有清香，有时间的味道，绕百年而不散。

通济堰的修建，在古代算得上大工程，参与人无数，但给后世留下的史料，经过民间千年口口相传，其实并不丰富。在堰口堤坝上，竖有詹司马、南司马石像，“二司马”是最初的建造者。石像边上的碑文，简述“二司马”建堰史。南朝梁天监四年，即公元505年，詹司马奏请在松阴溪与大溪江合流处筑堰坝，朝廷又遣南司马共治其事，首创拱坝形式得以建成，汇松阴溪水入堰渠，渠道自大坝至白桥注入大溪，全长23公里，灌溉农田2.5万亩。此后，又有郡人参政何澹，民间也称何丞相，奏请朝廷“为图久远，不费修筑”，调兵3000人，历时3年重建通济堰，大坝由原来的木筱结构改为结石结构。为使其永固，并造铁炉36座，用铁水灌入石坝缝隙中，使大坝牢不可摧。

通济堰名的出现，几乎是在古堰建造完成600多年以后。南宋绍兴八年，也就是公元1138年，据沈国琛《通济堰》载：“南渡后，汶上赵学老分宰县事，深羡是堰之利民勘博也，赐名‘通济以美之……”从此，通济古堰以其卓然的姿态，立碧湖平原之上，让瓯江两岸风调雨顺，再无水患之忧。

时间过去1500年，除“二司马”、何澹，与通济堰关系非同一般的还有南宋诗人范成大。范氏以田园诗留名，一生创作诗歌近2000首，其中大多为田园诗。但颇为诡奇的是范成大任处州（即如今的丽水），任职时间只有短短9个月，却成为处州史上功绩最为卓著的一位知府。而且，在范成大浩瀚的田园诗里，居然找不到与丽水有关的田园诗。不过，他与通济堰的不解之缘，却让他以另一种书写方式留下不朽诗篇。

通濟堰自古留有堰史、堰规，对筑堰、护堰有功者，均刻碑立于世。宋代范成大、明代汤显祖等曾任职处州的官员都曾经为通济堰树碑撰文。其中最著名的当系范成大《通济堰规》碑和南宋初年《通济堰图》碑及水系图碑。这些都是研究通济堰历史和管理制度的最珍贵水利文物和实物资料，不可多得。

范成大任職处州期间，主持修整通济堰。更为重要的是，他亲自制定和撰写堰规，立碑勒石，“文意赅简，书逼苏黄”，手迹犹在。他兴工3个月修复通济堰，并挥毫书写《通济堰规》20条，记言14行，立碑以告来者。此《堰规》已经沿用了数百年。《括苍金石志》称：“范公条规，百世遵守可也”，可见其价值所在。

至于范成大为何没有在处州留下他的田园诗，丽水博物馆张慧琴曾撰文分析。张文称：范成大乾道三年（1167年）十二月知处州，真正赴任是在乾道四年七月，乾道五年五月离任，因此在处州只有9个月。时间虽短暂，但为民办的实事甚多。如创义役，以解百姓当差的后顾之忧;修复通济堰，使民享其利;上《论不举子疏》，置专款养孤儿，并为民请命，减浙东丁钱等;同时，新建处州带郭浮桥——平政桥，此桥几经重修，在1984年小水门大桥建成前，一直是府城南北的唯一通道。其中创义役、修复通济堰在《宋史》本传中均有详细的记载。正是因为有“忧稼穑、悯老农”的忧民意识，诗人很想通过自己的吏治去为民办事，对于田园风光自然无暇顾及了。

然而，范成大留在通济堰的《堰规》，显然是更有浩然之气的田园诗。

我去丽水，正值雨季，连续数日密雨，从上游下泄的流水，已淹没古堰，只见微黄的流水，在堰坝之前汇成一个安静的湖，等到漫过坝体，向下游浩荡而去时，就是激流。激流之上，露出水面的，是两岸青山，和堰下的绿洲。其中一处小洲，流水溢过树丛，叠石不动，不由让人想起宋代晁公溯描写通济堰的诗句：“横江三百丈，遥见石嶙峋。”

沿通济堰顺流而下，两岸风景如画。其地天生丽质，也就有了古堰画乡的美名。坐船从古堰一侧渡向对岸，埠头一棵樟树，堪称树王。一树成林，遮住一个不小的广场，使烈日之下，也有了清凉之所。而在树旁的饭馆，如能吃上一尾瓯江的鱼，则更好。坐于窗下，可眺瓯江，远山如黛，几叶帆影，疏影横斜过窗前。

从远处眺望通济堰，我想起曾经主笔创作的浙江治水篇，有一种巨大的缺憾终于弥补的欣慰。同为宋，北宋有苏轼，疏浚西湖，因湖上一堤，为苏堤;南宋有范成大，西湖西行五百里，修古堰通济，而名留青史。他们都是诗人，都以诗名流芳，但都以改造或修缮水利设施而为民得利。一南一北，一前一后，异曲同工，“天下同归而殊途，一致而百虑”，说的就是范成大和苏东坡吧。

I made an unforgivable mistake years ago when I was in charge of writing a volume tracing Zhejiangs accomplished water control systems since very ancient times. I somehow failed to mention the Tongji Weir in Lishui in southern Zhejiang. The volume was part of a national collection of prominent water control systems in Chinese history. The collection came out in November 2011. A few months later， I received a letter from Wu Guangji， a prominent writer based in Lishui. He scolded me for my omission of the ancient irrigation system in Lishui. A cold sweat broke out in me and I shuddered at my glaring oversight when I was reading his letter. 

I apologized to him and promised to correct the dire mistake in a new edition of the volume. I was able to correct the mistake by adding a full-length essay on the ancient water control miracle in the new edition， but the oversight has been haunting me.

The Tongji Weir is a vast water control system first built in 505 AD and expanded， upgraded and maintained in the subsequent centuries. The curved low dam is 275 meters long， 25 meters wide and 2.5 meters high. It saves rainfalls in an area of 3，150 square kilometers in its upper streams. That is， it diverts about 200，000 cubic meters daily into ponds and reservoirs through a vast network of irrigation canals in the region.

In 2001， the weir system was inscribed on a national list and placed under protection of the state government. In 2014， it was honorably designated as a World Irrigation Project Heritage.

A temple stands near the weir in honor of the ancients who contributed to the building and maintaining of the water control system. Of the ancient relics are two stone statues in honor of Zhan Sima and Nan Sima. Zhan and Nan were two government officials in charge of building the original weir and a 23-kilometer canal which irrigated 16.6-square-kilometer farmlands. Later the low dam was restructured into a stone system strengthened with rocks all sealed off with iron poured into the dam. In 1138， which was about 600 years after the system first came into function， the weir system was officially called Tongji， which literally means bringing comprehensive benefits to people.

The Tongji Weir is well preserved in many ways. One of the outstanding features of the water control system is that it has maintained a complete set of stone steles created over the past dynasties. One of the steles， created by Fan Chengda （1126-1193） of the Southern Song Dynasty （1127-1279）， bears a complete text that documents 20 must-do rules for administration and maintenance of the weir. Created in the early years of the Southern Song， another stele presents a map of the weir system

Fan Chengda is celebrated in the history of Chinese literature for his nature poems which number over 2，000. He served as a local governor where the Tongji Weir system was for only nine months， but wrote no poems there. Instead， he was busily engaged in his administrative duties. He spent three months masterminding and carrying out a restoration project of the Tongji Weir system. Moreover， he conducted a number of projects that benefited local people a great deal. For example， he set up an orphanage system. He carried out a tax reduction. He had a bridge built. The bridge， which functioned well up to 1984， was a key part of the local road system.

Today， the well preserved ancient weir is at the core of a well known tourist attraction in Lishui. The landscape around the ancient weir is picturesque and there is a colony of artists based in a nearby waterside town. Artists and photographers gravitate toward the colony and fascinate themselves with the views of the natural beauty around them.

It was not until about ten years after I had penned an essay about the Tongji Weir that I first visited the ancient system. My visit occurred in a rainy season. After a few days of rain， the low dam was submerged by waters from the upper stream， forming a quiet lake. Waters cascaded over the low dam， flanked by emerald peaks on both sides. A small shoal， covered with a stand of trees， tried to resist the overflowing currents. The trees swayed， but the rocks there didnt budge an inch. A ferry pier by the weir was covered by a giant shady camphor tree， which was very ancient. A restaurant by the camphor tree was the right place to enjoy a fish dinner and enjoy the sight of the river and the peaks.