Thailand has a comprehensive and developed inland waterways system
which covers well over one-third of the country and extends over some 1,300
km of navigable waterways. Most of this length is in the Northern Corridor
between Bangkok and Uttaradit along the rivers Chao Phrya
and Nan, and the remainder along the Mekong river on the Thai-Laotian
border. The following discussions refer exclusively to the waterways in the
Northern Corridor which are the subject of the proposed project. The
principal navigable rivers are