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Mekong Sea Dyke – Concept Paper

October 1, 2011 3:28 am

Mekong Sea Dyke – Concept Paper

May 29 2011 in agriculture, aquaculture, climate change, communications, finance, flooding, food, Governance, habitat, hydropower, livelihoods, mekong delta, mekong ecoregion, salinity, sedimentation, The Mekong River, tourism, transport, Vietnam, wetland by Paul Stewart

In lieu of the previous post about sedimentation and marine fisheries and the recent meeting in Hanoi. This concept paper dropped into my postbag here at Mouth to Source.

It’s what can only be described as a MEGA project, the likes of which I’ve never seen before.

A 600 kilometre sea wall to enclose the Mekong Delta.

What do you think?

By Ngo The Vinh, M.D. of Viet Ecology Foundation.

The Multi-Purpose Sea Dyke – The Mekong Delta

From Possibility to Realization.

This is the second of three articles entitled “A Look Forward into the Next Half Century” discussing the prospects confronting the Mekong Delta. The first article offers an overview of the situation with this main conclusion: the governments bordering the Mekong are still convinced that hydropower remains the least expensive power source to sustain their national pace of economic development. Sooner or later, the exploitation of the hydropower potentials of the Mekong will prove to be an irreversible process that will forge ahead during the last half of this century regardless of the impacts that may be brought to bear on the eco-system of the Mekong, particularly of the Mekong Delta in Vietnam.

Evaluation of a short-term policy

Granted that the exploitation of the Mekong’s potentials for hydroelectricity is almost an ongoing process; the 70 million people of the Mekong still have the right to demand transparency in the assessments of the ecological impacts to ensure a policy of sustainable development.

We do need time to mount advocacy campaigns not only at the regional but also at the global levels. The pro-active experience with the Xayaburi Dam represents a welcome lesson for all.

Evaluation of a long-term policy

The following accumulative impacts are posing a threat to the Mekong Delta:

1/ The hydroelectric dams built upstream; especially the Mekong Cascades in Yunnan, China; and their mammoth reservoirs are reducing the water and the alluvium flow downstream. On top of that, the cutting down of mangrove forests, those natural barriers against seawater intrusion, brought about salinization in a good part of the Mekong Delta and soil erosion in the Ca Mau Peninsula.

2/ Global warming resulting from the emission of carbon dioxide causes the melting of glaciers at the North and South Poles or the Tibetan Highland also known as the Third Pole. Consequently, we are now witnessing a rise in the sea level. Scientists studying climate changes estimated that the sea level could rise from 0.80 meter to 1.5 meters by the year 2100. Should the sea level rise by only 1 meter, then, more than 75% of the Mekong Delta would be submerged under sea water.

 

Mekong Delta zones below mean sea level (in violet)

Confronted with the prospect of a Mekong Delta, being threatened by a penury of fresh water, soil erosion, and seawater intrusion; Vietnam has no other alternative but to implement a mega-project that calls for the construction of:

1) a multi-purpose dyke to prevent seawater intrusion and 2) two fresh water reservoirs in the natural depressions at Dong Thap Muoi and Dong Ca Mau.

This second article presents the major outlines of the Multi-Purpose Sea Dyke Project for the Mekong Delta.

(1) The idea is still in its conceptual phase and technical studies are being done jointly by Ngo Minh Triet, P.E., structural engineer and Pham Phan Long, P.E.. Mister Pham is also a founding member of the Viet Ecology Foundation.

The Objectives of the Multi-Purpose Sea Dyke

The main objective of the sea dyke is to prevent salinization resulting from a rise in the sea level coupled with a diminishing “minimum current flow” running down from upstream the Mekong to its Delta.

The long-term benefits to be derived from this project are manifold:

1) Prevention of salt intrusion and preservation of the eco-system in the Mekong Delta;
2) Ability to control floods and droughts and solve the problem of fresh water shortage;
3) Revitalization of the economic production in the basin by providing a strategic highway system along the coastlines;
4) Raising the quality of life for the Mekong Delta’s inhabitants in regards to its cultural, educational, and health aspects.

The immediate advantages are:

The dyke system is not located on land but offshore. As a result, no acquisition of private land is required and no opposition from the displaced population is to be expected. By the same token, since the proposed dyke is situated from 3 to 5 kilometers offshore, there would be numerous reservoirs built in the buffer zone between the dyke and natural coastlines.

With time, rain water combined with the fresh water flowing down from the rivers will help reduce the salinity of the water in those reservoirs. The resulting brackish water will allow for the raising of aquatic crops and bring in a substantial source of revenue.

The sea dyke will prevent soil erosions and help in the soil conservation efforts. In addition, it will add new land for farming and opportunities to build new cities. This must be regarded as one of the major returns on the substantial initial investment cost of the project.

The sea dyke will also serve as a beltway of the Mekong Delta. In engineer Ngo Minh Triet’s calculation, the dyke’s surface may measure up to 24 meters wide – large enough to construct a two-way highway which is indispensable for the maintenance of the dyke. Moreover, it also holds strategic implications in matters of transportation, economic development and defense.

 

Proposed 600 km Mekong Sea Dyke (broken blue line); sea depths 10m, 20m (yellow lines)

Experts in renewable energy believe that wind or sun are abundant along the sea dyke and can be harnessed. Another source of considerable revenue that cannot be overlooked is the development of ecotourism offering land sports like biking or water sports like waterskiing, boat racing, fishing…. to attract tourists to the region and improve the cultural and material life of the inhabitants of the Mekong Delta who greatly deserve it.

The projects outline and it’s feasibility

The geological composition of the sea bed in the vicinity of the coastlines off the Mekong Delta is as follows: 65% silt, 25% clay, and the remainder sand. The offshore area close to the coast is rather shallow and flat. It has an incline of 0.8:1000 around the estuaries and 5.0:1000 at the Ca Mau Peninsula.

The sea dyke will hug the coastline at an average depth of 3 meters. It will run from Go Cong in the east, go around the Ca Mau Peninsula and end at Ha Tien in the West. Its length will be about 600 kilometers measured from satellite photographs.

At the estuaries, sections of the dyke will be connected to each other by a network of movable bridges to ensure unhindered two-way boat traffic between the sea and the Mekong, all the way to Phnom Penh, considering that this river is an international waterway.

The labor force and technology employed will be for the most part local. The raw materials used will consist mainly of clay and sand taken from the seabed. They will be reinforced with pebbles, concrete cement and held in geotextile containers made of durable and water-absorbent polyesters.

 

Illustration of a typical cross section of the proposed Mekong sea dyke

Inland riverine ports like Can Tho will be relocated outside the dyke. Highways in fan shape will spread out from the dyke to the estuaries leading to the cities, towns or other important locations in the Mekong Delta. The ensuing shorter travel time will contribute immensely to the economic development as well as prosperity of the Mekong Delta.

This project was envisioned to benefit not only Vietnam but the entire Greater Mekong Subregion. Its implementation would require “decades” of work and its budget would reach in the tens of billions of U.S. Dollars coming from:

1) Vietnam’s national budget;
2) foreign aids from the United States, Japan, Australia, Germany, Denmark…
3) International institutions like the World Bank/ WB, the Asia Development Bank/ ADB, Japan International Cooperation Agency/ JICA, World Wide Fund/ WWF, Oxfam International, Food and Agriculture Organization of the United Nations/ FAO…

Over the past years, those organizations have shown interest in and extended their aids to a number of provinces like Ben Tre, Tra Vinh, Soc Trang to save the rice paddies or orchards that were being critically threatened by salinization. Unfortunately, their efforts only met with partial success due to the limited scope of their programs.

Most importantly, we need the participation of a “think tank” consisting of experts from different disciplines like hydrologists, geological surveyors, climatologists, ecologists… and Vietnamese of all walks of life both inside and outside the country. It would also be beneficial if experts with past experience from the Netherlands and South Korea (the Saemageum Seawall) were invited to participate in this effort.

In addition, the Mississippi River Commission, could be convinced to share its rich experience with dykes and dams with the project’s administrators. Through the initiative of the American Secretary of State, Mrs. Hillary Clinton, this Commission has established a sister relationship with the Mekong River Commission in July, 2009. (5)
.
A Vietnam faced with Life or death choice?

It is hard to visualize in anybody’s mind that in the second half of the 21st century, the following ominous scenario could possibly take place: the Mekong Delta, that rice bowl of the whole country, would no longer exist while the Tien and Hau would turn into dead rivers because the fresh water that flows down from the north is being retained in the dam reservoirs upstream and replaced by the seawater intruding from the rising East Sea.

Confronted with such a gloomy prospect, a question immediately comes to mind: “What must we do?”

The answer to that question surely requires a lot of hard thinking on the part of the people. To come up with a “great idea” they will have to summon up novel thoughts, innovative approaches, and unyielding determination. Vietnam, throughout its long history, is scourged by constant warfare. Now is the time for the Vietnamese to leave behind them a “Culture of War” and embrace a “Culture of Peace”. Should this project be adopted, it would mark a construction endeavor not only crucial for the Vietnamese people’s survival but also a major pioneering “Green Growth Project” in this Millennium.

The food security of the World

To this day, Thailand and Vietnam still remain the two top rice producers in the world. But the irony is: the farmers in the Mekong Delta still live under the “poverty level” while their offspring are facing the prospect of losing their “living space”. Furthermore, the world population is growing at an exponential rate in spite of a decline in the major food sources.

To save the Mekong Delta does not simply mean to save a fertile region of Vietnam. It also implies the preservation of an important rice bowl of the world. The advisor on climate changes to the United Nations, Mr. Koos Neefjes, had this “inconvenient truth” to say: “Climate change isn’t caused by a developing country like Vietnam, but it is suffering the consequences” (6)

Looking at the issue from the above perspective, we can say that the participation of the developed countries in the Multi-Purpose Sea Dyke Project is an act of “social justice” to fulfill an international obligation in this era of globalization.

Ngo The Vinh, M.D. California, 05-24-2011

References:

1/ Mekong Sea Dyke, A Concept Paper / Draft, April, 2011, Ngo Minh Triet, P.E.; Pham Phan Long, P.E., Viet Ecology Foundation
2/ Lancang-Mekong Initiative_ A Foundation for the Long Term Cooperation and Prosperity for Chian and ASEAN, Phạm Phan Long, P.E., Viet Ecology Foundation Jan, 2011, http://www.vietecology.org/Article.aspx/Article/64
3/ Mekong-Cuu Long 2011_ A Look Forward Into the Next Half Century[1]; Ngo The Vinh, M.D. Viet Ecology Foundation, Jan 11, 2011, http://www.vietecology.org/Article.aspx/Article/63
4/ US – Mekong Basin Cooperation follows ASEAN Meeting, Vientiane, Laos PDR, Jul 30, 2009, http://www.mrcmekong.org
5/ Mekong-Mississippi Sister-River Partnership_ Similarities and Differences; Ngo The Vinh, M.D. Viet Ecology Foundation, Aug 2009, http://www.vietecology.org/Article.aspx/Article/58
6/ Vietnam Finds Itself Vulnerable if Sea Rises; Seth Mydans. The New York Times, September 24, 2009

Visit Viet Ecology Foundation

http://mouthtosource.org/rivers/mekong/2011/05/29/mekong-sea-dyke-concept-paper/

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