Pearl River -

The largest river in the South China region of China. Also known as the Yuejiang River. It has three major tributaries, the Xijiang River, the Beijiang River, and the Dongjiang River, but the Xijiang River is the longest and the main stream. It has a total length of 2,129 km and a drainage area of ​​425,700 square km. The Xijiang River originates from the Nanpanjiang River flowing out of Yunnan Province, and on its way east it merges with the Beipanjiang River to become the Hongshuihe River, and then merges with the Liujiang River to become the Qianjiang River, and with the Yujiang River at Guiping to become the Xunjiang River, and is called the Xijiang River after merging with the Guijiang River at Wuzhou. After Sanshui, west of Guangzhou City, it flows through the Pearl River Delta and empties into the sea at Mataomen. The Xijiang River drainage area accounts for approximately 78% of the Pearl River basin area. The upper and middle reaches of the Xijiang River are famous limestone areas in China, and are rich in scenic beauty, including limestone gorges Huangmao Gorge, Dateng Gorge, and Guilin. The upper reaches of the tributary Jiang River are connected to the Yangtze River (Changjiang) system by the Lingqu Canal. The Beijiang River originates at Dayuling, which forms the border between Jiangxi and Guangdong provinces, flows south, and its main stream empties into the sea at Hongqili. It is 582 km long. The Dongjiang River originates in the southern part of Jiangxi Province, flows southwest, and finally empties into the sea at Humen. It is 503 km long.

These three tributaries are actually three independent rivers, but in the Pearl River Delta they branch out and are interconnected in a net-like pattern. The amount of rainfall is high in summer, so the water volume also increases in summer. Typhoons also frequently strike in summer, and the heavy rains that accompany them often cause floods. Flood damage is greatest in the flat delta region. However, the overall abundance of water makes navigation favorable, with a year-round navigation distance of 1,200 kilometers. In terms of power generation, eleven dams have been built in a stepped pattern from the Panjiang River to the Hongshui River, including Tianshengqiao, Yantan, Lubuge, Dahua, and Autan. There are also power plants at Xijin on the Yujiang River, Zhaoping on the Guijiang River, Ruyuan on the Beijiang River, and Huangjiang River. There are also power plants that use underground rivers.

[Aoki Chieko and Kono Michihiro]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

中国、華南(かなん／ホワナン)地方最大の川。別称粤江(えっこう／ユエチヤン)。西江(せいこう／シーチヤン)、北江(ほくこう／ペイチヤン)、東江(とうこう／トンチヤン)の三大支流があるが、もっとも長い西江を主流としている。全長2129キロメートル、流域面積は42万5700平方キロメートル。西江は雲南(うんなん／ユンナン)省から流出する南盤江(なんばんこう)を源流とし、東流する途上で北盤江をあわせて紅水河(こうすいが／ホンショイホー)とよばれ、さらに柳江(りゅうこう)をあわせて黔江(けんこう)、桂平(けいへい／コンピン)で郁江(いくこう)をあわせて潯江(じんこう)と名を変え、梧州(ごしゅう／ウーチョウ)で桂江(けいこう／コイチヤン)と合流したのち西江と称する。広州(こうしゅう／コワンチョウ)市西方の三水(さんすい／サンショイ)以後は珠江デルタを経て磨刀門(まとうもん)で海に注ぐ。西江の流域面積は珠江流域面積の約78％を占める。西江の上・中流域は中国でも著名な石灰岩地帯であり、名勝が多く、石灰岩峡谷の黄茅(こうぼう)峡、大藤(だいとう)峡、桂林(けいりん／コイリン)を中心とした景勝地がある。また支流の江(りこう)上流では霊渠(れいきょ)により長江(ちょうこう／チャンチヤン)（揚子江(ようすこう／ヤンツーチヤン)）水系と結ばれている。北江は江西(こうせい／チヤンシー)・広東(カントン)両省の境界をなす大庾嶺(だいゆれい／ターユイリン)に発し、南流して本流は洪奇瀝(こうきれき)で海に注ぐ。全長582キロメートル。東江は江西省南部に発し、南西流して最後は虎門(こもん／フーメン)で海に注ぐ。全長503キロメートル。

　以上の3支流は実際は三つの独立の河川であるが、珠江デルタにおいて網状に分岐し相互に連なっている。夏季の降水量が多量となるため、水量も夏に増加する。また夏季には台風の襲来が多く、これに伴う大雨によって洪水の発生をみることも多い。洪水の被害は平坦(へいたん)なデルタ地帯に大きい。しかし全般的に水量が豊富であるところから航運の条件に恵まれ、通年航行距離は1200キロメートルに及ぶ。発電利用の面では南盤江から紅水河にかけて天生橋、岩灘、魯布格(ルプゲ)、大化、悪灘など階段状に11のダムが建設され、また郁江の西津(せいしん)、桂江の昭平、北江の乳源、滃江(おうこう)などにも発電所があり、地下河川利用の発電所もある。

［青木千枝子・河野通博］

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