The Mekong ViewedFrom The Mississippi
By Chinh Phuc & Ho Hung
Climate change and human development have exerted pressure on all the rivers and big deltas around the world. The Mekong River shares many similarities with the Mississippi River in the U.S. and may encounter the same problems.
There have been many natural disasters in the Mississippi Delta, including Hurricane Katrina, which flooded 150,000 houses, killed over 1,000 people, inflicted damage of as much as US$100 billion and caused 40 hectares of land in the delta to vanish. These problems arose due to excessive exploitation of natural resources and the adverse impacts of climate change.
Threat fromhydropower plants
The Mississippi River is 3,734km long and passes through 10 states in the U.S. In 1700, the first canal was built in New Orleans, connecting the river to the sea. In 1850, a law governing the exploitation of marshes triggered the development of hundreds of kilometers of canals and dikes, with many pumping stations, sewage pipes and irrigation systems, aimed at boosting transport and transforming the wetlands into residential, industrial and agricultural areas.
Dozens of hydropower plants sprang up on the upper Mississippi River in 1953-1963 to meet the demand for electricity and deal with floods. Ironically, immediately after the establishment of these plants, natural disasters started to sweep through the region with greater intensity. Many downstream areas suffered severe floods.
Efforts to construct dikes in 1963-1990 to rectify these problems turned out to be another mistake. Prior to the construction of these dikes, the river often overflowed its banks, enriching nearby farmland with silt and keeping the ground above sea level. Unfortunately, these benefits vanished after the proliferation of the dikes, which caused the silt to flow into the Gulf of Mexico. So far, the costs and benefits of these dikes remain unclear.
Hurricane Katrina in 2005 and Hurricane Rita in 2007 destroyed the coastal areas of Louisiana and New Orleans in particular. Subsequent reconstruction efforts were both tardy and costly. Many longtime settlers encountered enormous problems and had to leave the area, while the remainder had to build new houses six meters above sea level to cope with future disasters.
The authorities are aware that coastal wetlands cope with natural disasters better than the most solid buildings. Mangrove forests, marshes and coastal grasslands can withstand natural disasters effectively. Cindy Thatcher from the U.S. Geological Survey (USGS) says that, unfortunately, New Orleans has only a few wetlands left. These wetlands are widely considered as the best shelter against natural disasters. Without them, the city would suffer greater damage, given the rising number of natural disasters sparked off by climate change and rising sea levels. Humans have altered the flow of the Mississippi River. To worsen matters, climate change is increasingly evident, adversely affecting the ecological system of wetlands.
To tackle these problems, the U.S. federal government financed 200 projects aimed at redeveloping the coastal wetlands in Louisiana, with a total investment of nearly US$1 billion, in 1990. However, Dr. Scott Wilson from USGS says that if Louisiana and the city of New Orleans want to succeed in such endeavors, they will need US$15-20 billion. Of course, it is virtually impossible to undo all the damage. Wilson says that the best thing to do is to set the rivers free.
The Mekong River –a closer look
The Mekong River passes through China, Myanmar, Thailand, Laos, Cambodia and Vietnam, and encounters the same problems as the Mississippi River does. Dr. Chu Thai Hoanh from the International Water Management Institute says that the hydropower plants which China and Laos are developing upstream will store up to 16% of the water volume in the river (475 billion cubic meters per annum), affecting 50% of the Mekong River’s water volume. The water flow and silt volume downstream will certainly change.
Countries such as Thailand and, most notably, Laos and Cambodia, are also trying to capitalize on water from the Mekong River to develop farmland, estimated to balloon by over 1.8 million hectares.
In the downstream areas, canals aimed at boosting transport, irrigation and so on are destroying cajuput forests. Dikes set up to deal with floods, combat saltwater intrusion and help with shrimp farming have also hampered coastal mangrove forests. The tragedy plaguing the Mississippi River over the past four decades may also play out along the Mekong River.
Since this river passes through six countries, a consensus on how to exploit it optimally while battling against both climate change and rising sea levels is hard to reach. The consequences for the Mekong River are forecast to be as grave as those gripping the Mississippi River, while the remedies are far more difficult to implement.
Erosion is inflicting damage on areas along the Hau River and the Tien River, which are tributaries of the Mekong River. Several wetlands are vanishing due to human exploitation and climate change. The pressure on the Mekong Delta is huge.
Up to 54.7 million people residing downstream along the Mekong River depend on it for a living and are likely to suffer tremendously when disasters strike. Therefore, U.S. scientists believe that lessons drawn from construction and development projects along the Mississippi River should be shared with the authorities of the countries along the Mekong River. Forecasting the detrimental impacts of human activities and climate change on the Mekong River will prove immensely useful to those who count on the river for survival.