Tour company TransMékong operates tours through the Mekong delta on three authentic wooden cabin cruisers called Bassac. The name comes from the older name of the Hậu Giang river, the second but larger branch of the Mekong. This splits from the main Mekong flow at Phnom Penh, and then grows into its largest tributary. TransMékong has generously provided us this interesting historic information on one of the largest river deltas in the world.
In Vietnamese, the Mekong is called "Cửu Long", which is Sino-Vietnamese for Nine Dragons, after the number of its mouths. However, as you try and count the branches of the Mekong that actually reach the sea today, nine is one of the few numbers you will not reach. The dragons are moving.
The estuaries of the Mekong circa 1910
With the siltation and erosion from the sea, the rains and its own flow, the Mekong is changing and evolving. Islands propagate, oxbows appear, mouths silt up.
It takes an old map to figure out the origin of the nine dragons, like this one, dated circa 1910, where we see the following mouths: on the Hậu Giang river, alias The Bassac, are the Đình An, Bassac and Trân Bé mouths, or Cửa. The Cửa Đình An is the trading way today, although so much sitled that there is now a project to open a separate canal through Trà Vinh for the larger freighters. The Bassac mouth is now completely silted up and disappeared.
The rivers Cổ Chiên, with Cửa Cung Hậu and Cửa Cổ Chiên, and Hàm Luông with Cửa Hàm Luông, are still there and are similar today to what they were in the early XXth Century. Tremendous change occurred on the Mỹ Tho river, the end of the Tiền Giang: the Cửa Ba Lai, which was the end of its own river, was entirely silted up and the river nearly completely disappeared, into what is now known as Bình Đại district, in Bến Tre. Cửa Đại and Cửa Tiểu, the large and small mouths of the first river, are still here, Cửa Đại being the main commercial route towards Cambodia today.
Since the French arrived in the then Cochinchina, they were tempted to open routes to upstream the Mekong delta into Cambodia and then Laos, and as early as 1858, at the time they landed in Tourane (Đà Nẵng), they launched a reconnaissance expedition to chart the larger ways of the Mekong delta, much earlier than the famous Doudart de Lagrée exploration in 1866.
The map from the 1858 expedition
If the geography and proportions of the rivers differ a bit from reality, their topology is rather correct, as far as navigators of the main arteries could discover at that time. Cù Lao Giêng, Cù Lao Ông Hổ, Cù Lao Mây, many details of the Mekong topography are present, and we can somewhat rely on the map to appraise the evolution and changes of the river and its trading waterways.
Many of the main canals are not there, especially Kênh Chợ Gạo and Kênh Lấp Vò, between Mỹ Tho on the Mekong and the common trunk of the Vàm Cò rivers (here named Vai Co), but there are some rạch and arroyos that were at that time of commercial use and that have since become quite secondary, as the Kinh Ba Bio, between Saigon and Cái Bè. The river Măng Thít, between Trà Ôn and Cổ Chiên, is not charted, but its mouth at the confluent on Cổ Chiên (then Co Khiên) is present on the map. The Trà Ôn canal, which was to become the Nicolai canal later in the XXth Century, was certainly already there, at least in its original, river form.
More importantly, there seems to be a natural connection from the first river to Cổ Chiên, just upstream of the effluence of Hàm Luông, at about the location of the present day's Chợ Lách canal. The canal runs 6km across the An Bình peninsula, which is nearly 2km across at its thinnest. Could there have been a natural connection? Maps of 1910 show the canal as it is today, Could it have silted up that fast? Maybe it could: a rather complete map dated 1929 does not show it, nor any connection.
TransMékong is a family company established in 2003 in Cần Thơ, in the heart of the Mekong delta, by a Franco-Vietnamese couple.