Yodogawa

The river flows out from the southern end of Lake Biwa, through the Kyoto Basin and the northern half of the Osaka Plain, and empties into Osaka Bay. It is 75 kilometers long and has a drainage area of ​​8,240 square kilometers, which is about one-quarter of the area of ​​the Kinki region. There are many cities in the basin, including Osaka and Kyoto, and it forms the basis of social, economic, and cultural development in the Kinki region. The upper reaches are called the Seta River, which eventually becomes the Uji River, and at the narrow section of Yamazaki on the border between Kyoto and Osaka Prefectures, it joins with the Kizu River and Katsura River to form the Yodo River. In the downstream, it separates from the Kanzakigawa River at Eguchi in Higashiyodogawa Ward, separates from the Shin-Yodogawa River at Kema in Miyakojima Ward and runs through the Osaka city area, branches into the Dojimagawa River and the Tosaborigawa River at Nakanoshima, and from the western end of Nakanoshima it separates into three rivers, the Ajigawa River, the Shirinashigawa River, and the Kizugawa River, before flowing into the sea. In terms of river administration, the Yodogawa River is referred to as the section from the Amagase Dam in Uji City (the outlet of the Kansai Electric Power Company's power plant) to the mouth of the Shin-Yodogawa River (1965 Ministry of Construction Notice), and the course from Kema to the Ajigawa River is distinguished as the Old Yodogawa River.

Since ancient times, the Yodo River has been deeply involved in political and cultural trends as a transportation artery in the Kinai region. In ancient times, Naniwa-kyo was located at the mouth of the river, Nagaoka-kyo in the middle reaches, and Heian-kyo in the upper reaches. In the Middle Ages, water transportation at the mouth of the river shifted to the Kanzaki River, and Eguchi and Kanzaki (Amagasaki City) flourished as river ports. In the early modern period, riverboats frequently traveled between Fushimi and Hakkenya in Osaka. Toyotomi Hideyoshi built a levee (Bunroku Tsutsumi) on the left bank of the Yodo River in 1596 (Bunroku 5) to create a shortcut between Fushimi and Osaka, and in the Edo period the levee was improved and the road was renamed the Kyoto Kaido as an extension of the Tokaido, with post stations at Fushimi, Yodo (Fushimi Ward), Hirakata, and Moriguchi established along the river, and the road flourished as a river port. Although water transportation declined after the Meiji period, the river continued to play an extremely important role as a source of drinking water and industrial water for the Kyoto-Osaka-Kobe region. However, floods frequently occurred, and flood control works were carried out, such as the Araiseki Weir at Nango and Kema, the three river diversions at Yodo, and the excavation of the New Yodo River, and in 1983 (Showa 58), the Yodo River Ozeki Weir was built in Kema.

[Noboru Maeda]

"Yodo River - Nature and History (Osaka Bunko 1)" by Sei Tetsukawa and others (1980, Shoraisha)

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

琵琶湖(びわこ)の南端から流れ出し、京都盆地、大阪平野北半部を流れて大阪湾に注ぐ川。延長75キロメートル。流域面積8240平方キロメートルに及び、近畿地方の約4分の1の広さにあたる。流域には大阪市、京都市をはじめ都市も多く、近畿における社会、経済、文化の発展の基盤をなしている。上流部は瀬田川(せたがわ)といい、やがて宇治川(うじがわ)となり、京都・大阪府境の山崎(やまざき)の狭隘(きょうあい)部で木津川(きづがわ)・桂川(かつらがわ)をあわせて淀川となる。下流では、東淀川区江口(えぐち)で神崎川(かんざきがわ)を分かち、都島(みやこじま)区毛馬(けま)で新淀川と分かれて大阪市街地を貫通、中之島(なかのしま)で堂島川(どうじまがわ)と土佐堀川(とさぼりがわ)に分流、中之島西端からは安治川(あじがわ)、尻無川(しりなしがわ)、木津川の3分流となって海に流入する。河川行政上、淀川とよぶのは宇治市天ヶ瀬(あまがせ)ダム（関西電力発電所放水口）から新淀川河口までで（1965年建設省告示）、毛馬から安治川に至る流路は旧淀川として区別している。

　淀川は古来、畿内(きない)の交通動脈として政治・文化の動向に深く関係してきた。古代には河口部に難波京(なにわのみやこ)が、中流部に長岡京(ながおかきょう)、上流部に平安京が置かれた。中世には河口部の水運が神崎川に移り、江口と神崎（尼崎(あまがさき)市）が河港として栄えた。近世には伏見(ふしみ)と大坂の八軒家(はっけんや)との間に川舟が盛んに通航した。豊臣(とよとみ)秀吉は1596年（文禄5）淀川左岸に堤防（文禄堤(ぶんろくづつみ)）をつくり、伏見(ふしみ)―大坂間の近道としたが、江戸時代になって堤が整備されて東海道の延長として京街道となり、伏見、淀（伏見区）、枚方(ひらかた)、守口(もりぐち)の宿駅が置かれ、河港としても栄えた。明治以降、水運は衰えたが、京阪神地方の上水源、工業用水源としてきわめて重要な役割を果たしている。一方、洪水をたびたび起こし、治水対策として南郷(なんごう)・毛馬の洗堰(あらいぜき)、淀の3川分流、新淀川の開削などの治水工事が行われ、1983年（昭和58）には毛馬に淀川大堰(おおぜき)が設けられた。

［前田　昇］

『鉄川精他著『淀川――自然と歴史〈大阪文庫1〉』（1980・松籟社）』

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