The Chao Phraya (แม่น้ำเจ้าพระยา) is a major river in Thailand, with its low alluvial river plain marking the mainland of the country.
According to many European old maps, the river is named as Menam
or Mae Nam
, the Thai word for river (Me or Mae is "Mother", Nam is "Water"). The name Chao Phraya
is a Thai feudal title
, which can be translated as General
. In the English-language media in Thailand the name is often translated as River of Kings
The Chao Phraya begins at the confluence of the Ping
river at Nakhon Sawan
(also called Pak Nam Pho) in the Nakhon Sawan province
. It then flows from north to south for 372 km
from the central plains
and the Gulf of Thailand
. In Chainat
, the river splits into the main river course and the Tha Chin
river, which then flows parallel to the main river and exits to Gulf of Thailand the about 35 km west of Bangkok in Samut Sakhon. In the low alluvial plain which begins below the Chainat dam, many small canals (khlong
) split off from the main river. The khlong are used for the irrigation of the region's rice paddies.
The cities along the Chao Phraya are Nakhon Sawan, Uthai Thani, Chainat, Singburi, Ang Thong, Ayutthaya, Pathum Thani, Nonthaburi, Bangkok and Samut Prakan, listed from north to south. These cities are among the most historically significant and densely populated settlements of Thailand precisely because of their access to the waterway.
In Bangkok, the Chao Phraya is a major transportation artery for a vast network of ferries and water taxis, also known as longtails.
The principal tributaries of the Chao Phraya River are the Pa Sak River
, the Sakae Krang River
, the Nan River
(along with its principal confluent the Yom River
), the Ping River
(with its principal confluent the Wang River
), and the Tha Chin River
. Each of these tributaries (and the Chao Phraya itself) is further tributed by additional minor tributaries often referred to as khwae
. All of the tributaries, including the lesser khwae, form an extensive tree-like pattern, with branches flowing through nearly every province in central and northern Thailand
. None of the tributaries of the Chao Phraya extend beyond the nation's borders. The Nan and the Yom River flow nearly parallel from Phitsanulok
to Chumsaeng in the north of Nakhon Sawan province. The Wang River
enters the Ping River near Sam Ngao district in Tak province
Chao Phraya Watershed
The expanse of the Chao Phraya River and its tributaries, i.e. the Chao Phraya river system, together with the land upon which falling rain drains into these bodies of water, form the Chao Phraya watershed.
The Chao Phraya watershed is the largest watershed in Thailand, covering approximately 35% of the nation's land, and draining an area of 157,924 km².
The watershed is divided into the following basins:
The mountainous natural boundary of the watershed forms a divide, which has, to some degree, historically isolated Thailand from other Southeast Asian civilizations. In fact, in northern Thailand, the divide roughly corresponds to a long section of the political border of present-day Thailand. Southern portions of the divide's boundary correspond less to the nation's political border, because isolation in this area was prevented by the ease of transportation along the lowlands surrounding the Gulf of Thailand, allowing a unified Thai civilization to extend beoynd the watershed without issue.
Chao Phraya Basin
The Chao Phraya Basin is defined as the portion of the Chao Phraya Watershed drained by the Chao Phraya River itself, and not by its major tributaries or distributaries. As such, the Chao Phraya Basin drains 20,126 km² of land.
Chao Phraya Delta
The Tha Chin River
is the major distributary of the Chao Phraya River. The expanse of the Chao Phraya and Tha Chin
Rivers and their distributaries, starting at the point at which the distributaries diverge, together with the land amid the triangle formed by the outermost and innermost distributary, form the Chao Phraya Delta.
The many distributaries of the Chao Phraya delta are interconnected by canals that serve both for irrigation and for transportation.
- Bangkok Waterways, William Warren and R. Ian Lloyd, Asia Books, ISBN 981-00-1011-7.