Understanding Canals in Bangkok Using Historic Maps and GIS

Abstract

Bangkok the capital of Thailand is a semi –aquatic city. Constructed in, rather than around, the Chao Phraya delta for centuries it has relied on canals for irrigation, flood mitigation and transportation. As the city has expanded, especially in the last three decades, the canal networks have been disrupted; filled in, paved over, and cut off from the river in favor of paved roads. Canals once connected almost every home, temple and palace in Bangkok. Canal access to the water was a central aspect of Bangkokian public life, today that access is becoming increasingly limited and privatized. Canals have a special connection to the urban design of Bangkok; besides their obvious uses for irrigation, flood control and transportation canals have another element central to their relationship to the urban life; spirit. In Thai Buddhism water is a scared element, a regional syncretism carried into the present from pre-Buddhist animist shaman cults. This can be seen in many ways and has been documents by many scholars, including Sumet Jumsai the renowned Thai anthropologist (Jumsai, 1988). The Naga, the sacred water serpent of Buddhist cosmology, is said to have protected the Buddha from a flood, sheltering him under its giant cobra hood and lifting the Buddha up from the water with its own coiled body (Jumsai, 1988)Throughout Thai temples tribute is played to the brave Naga, often the serpent adorns the stairs leading into temples, but it is also a common motif in frescos, paintings and tattoos. This study investigates the hypothesis that the symbolic connection between the temples and the spiritual role of water has been enough to shape the urban landscape of Bangkok. I hypothesize that where there are temples there are also canals. I believe that areas where temples exist are more likely to be connected to waterways and that the waterway networks may be less disturbed in areas with many temples than waterway networks that are not near temples. This study will use a variety of methods but will mostly focus on map analysis, both physical maps and GIS data. Historical research was conducted through online databases, the Harvard libraries, and with the help of the Thai National Archives in Bangkok. The study relies on 8 sample areas, each selected from a different zone along the Chao Phraya River in Bangkok. Aerial photos from a 1932 Thai Navy Survey were compared manually with satellite images taken in 2016. Measurements were made concerning the observable length of canals and percentages of disturbance calculated. The sample areas were then examined for temples, with notes taken regarding the status of water features in the 1932 photos as compared to the 2016 images. The study found temples have reliably retained their connection to canal access, and canal networks were more likely to be robust in study area with more temples than in those with fewer temples.