Chao Phraya デルタの運河開発に関する一考察 (I) : Ayutthaya朝よりRatanakosin朝四世王治世まで

Abstract

The historical development of hydraulic works carried out in central Thailand seems closely determined by the physiography of the region, which is devided into the old delta, the deltaic high and the delta flat (Takaya : 1971). This article aims to analyze the regional change of the Chao Phraya delta seen as the Lebensraum (geographical living space) of the Siamese people, by investigating the formative process of the canal system before the introduction of the modern irrigation-transportation system operated by Krom Khlong (Department of Canals.) Throughout Ayutthayan and the early Ratanakosin periods, many canals of military and transportational purposes were excavated by the Siamese kings in the delta flat region. This region, being sparesely populated, was not so important for rice cultivation untill the mid-nine-teenth century. In the mid-nineteenth century, however, the Siamese Government, in order to meet the foreign demand for rice, tried increasing rice production by expanding rice land and, for this purpose, started the construction of a canal system for transportational and irrigational purposes on the west bank (Mahasawat, Phasicharoen, Damnoensaduak, etc.). In spite of the efforts of the government, the reclamation of rice land did not yield the expected result as is seen in the case of the Mahasawat canal; although the large scale land-holding developed by royal families and official nobles, vast amounts of land thus occupied were left uncultivated. (to be continued)