“Water has become expensive, and it will be even more expensive in the future, which will make it the ‘blue gold’ of the 21st century”. Ricardo Petrella, 3/2000

“For every claim to virtue made by the proponents of big dams, there is a clear-cut, factual and demonstrable refutation”. Elmer Peterson, Big Dam Foolishness, 1954

“In my view, nature is awful and what you do is cure it”. Camille Dagenais, Canadian dam engineering firm SNC, 1985

To The Friends of The Mekong
and VN2020 Mekong Group

FOREWORD: This is the last of a three-article series entitled “Mekong - A Look into the Next Half Century” dealing with the future of the Mekong Delta.

The first article sketched a general overview of the issue and offered these observations: hydroelectricity still remains the least costly source of power to meet the needs of economic development. Consequently, the exploitation of hydro-power on the Mekong is an irreversible process that will move ahead regardless of oppositions that may be raised along the way. What is needed now is a macroscopic plan to neutralize the cumulative impacts caused by climate change and the hydroelectric dams built upstream.

The second article entitled “The Multi-purpose Sea Dyke / MSD” proposed a bold project primarily geared to prevent seawater from intruding into the basin and save the Mekong Delta from being submerged should the sea level rise by 1 meter in the wake of global warming in a not-so-far future. Other added benefits to be derived from this project included: water reservoirs, land reclamation, improvement of the transportation networks, and higher standards of living for the basin’s inhabitants. (3)

This third article advocates the construction of fresh water reservoirs in the natural depressions of the Đồng Tháp Mười and Cà Mau swamplands in order to store the annual rainfall as well as the water coming down from upstream the rivers. By doing so, we will no longer watch all that water flow wastefully through the estuaries into the East Sea. On the other hand, we can use the water thus saved to meet the immediate drinking water, cultivation and industrial needs of the 20 million inhabitants of the Mekong Delta. More importantly, we will be able to preserve the underground aquifers so that they can continue to wash away the alum that causes the acidification of the entire farm lands in the region.

All the three above articles in the trilogy named “Mekong- A Look into the Next Half Century” are conceptual in nature. They offer a tentative picture of a future several decades down the road and the readers are encouraged to look at them as a collection of open-ended information that will be complemented and updated by interested parties as Mother Nature and humankind evolve with time. At the moment of this writing, in 2011, it is beyond the ability of the writer to fully visualize what that future would hold for us.

A case in point: in the first article, it was mentioned that should the sea level rise by 1 meter, 90% of the Mekong Delta’s area would be covered by seawater (2). However, Mr. Trần Thức, the Director of Vietnam’s Institute of Climatology, Hydrology, and Environment predicted that “In the event the sea level registers a one-meter increase then the entire Mekong Delta – that is 100% of it – will be submerged”. On the other hand, based on their own research on the topography of the region, MM Ngô Minh Triết and Phạm Phan Long suggested a more conservative estimate: “Should the sea level rise by one meter, 50% of the Mekong Delta would go under the water and an additional 25% would turn into storm surge zone”.

To conserve the Mekong Delta requires that we embark on a protracted journey. The works done by this writer can be compared to a “drop of water” in the open sea, a small contribution to the intellectual wealth of our people. To survive on this land of destiny, our people have to constantly struggle against the threat of invasion from the North and the increasingly unforgiving elements from Mother Nature.

THE GEOGRAPHY AND DEMOGRAPHY OF THE MEKONG DELTA

Out of the seventeen estuaries of the Mekong, seven of them are tributaries of the Tiền and Hậu Rivers. It is through these very waterways that seawater intrudes into the basin. In 2010, it reached as far as 128 kilometers inland. According to an estimate by the Institute for Hydrological Planning in the South [Vietnam], the basin’s fields are covered by as much as 1.5 billion cubic meters of seawater during the dry season per day. This figure can grow to more than 25% higher during the rising tide (7).

After 1975, dikes were built around the estuaries to ward off salinization. Unfortunately, they proved to be only temporary measures because once the sea level starts on a sustained rise, both the areas bordering the river mouths and the entire basin will become inundated by seawater. Therefore, a mega project to construct a multi-purpose sea dyke must embody a strategic approach offering long-term solutions to the problems.

It is interesting to recall an anecdote that took place between Peter White, the reporter of the National Geographic, and the Vietnamese Minister of Information, Mr. Tôn Thất Thiện in 1968. Let us read what Mr. White had to say about it: “First I studied the maps. Then a U.S. Army plane carried me high and low over all the likely place, where muddy beaches and mangroves swamps meet the South China Sea. I did my best, but I could only find eight dragons. Yet how could that be, when the Vietnamese call the Mekong River the Cửu Long Giang – the River of the Nine Dragons?... I consulted my friend Tôn Thất Thiện, long a mentor on matters Vietnamese. Now he was Minister of Information in Saigon. He smiled. “There really are only eight,” he said. “But eight is not a lucky number. It has to be seven or nine. So we had to find another one, and we did. But it is very small, very narrow, and less than 10 miles long. I hope you are not too unhappy to have missed it.” (8)

THE TWO DEPRESSIONS IN THE ĐỒNG THÁP MƯỜI AND CÀ MAU PLAINS

In addition to the water reservoirs to be built along the future 600-kilometer long Multi-Purpose Sea Dyke (MSD) (3), there are two natural depressions in the Mekong Delta that are presently serving as natural reservoirs storing the rain water of the Rainy Season. The Tonle Sap is the only river in Cambodia that cyclically reverses its course depending on the Dry or Rainy Season. For that very reason, the Tonle Sap’s area can undergo drastic changes during the year: In the Dry Season, it measures about 2,500 km2. Nevertheless, when the Rainy Season comes (from May to September), the water level in the Mekong surges dramatically creating tremendous pressure forcing the Tonle Sap River to reverse its course and flow into the Tonle Sap Lake. As a result, the water in the lake rises from 8 to 10 meters and overflows its bank causing its area to grow fivefold to about 12,000 km2. The forests around the Tonle Sap Lake become flooded and are turned into a giant breeding ground for the fish population that accounts for approximately 60% of Cambodia’s fish supply. At the end of the Rainy Season, around November, the Tonle Sap reverts to its normal course and it is the time to celebrate the Water

Figure 1: Salinity intrusion 1996-2010

Festival or Bon Om Tuk. At the Quatre Bras, the meeting place of four river tributaries, the fish migrating down from the Tonle Sap Lake will either follow the Lower Mekong to go into in the Tiền River or stay their course on the Bassac River to enter the Hậu River. In both cases, those migratory fish end up into either the ĐồngTháp Mười or Cà Mau natural depressions. There, they multiply rapidly providing a plentiful supply of food source to the inhabitants of the Mekong Delta.

While the offshore construction of the MSD does not necessitate a costly outlay to pay for land acquisition, it is a different story with the building of the two fresh water reservoirs in the basin. The need to displace then relocate the local people would prove a challenging hurdle at first. Hopefully, if they are treated fairly and remunerated equitably for their losses, it would be possible to obtain their consent and cooperation. It is all for the good of the Mekong Delta and the future generations.

We need a policy marked with transparency and aimed to serve the common good. Once that condition is met, it would not be too hard to convince the inhabitants of the Mekong Delta who nurture a deep love for their land to make the needed sacrifice to ensure a stable future for all.