MEKONG DELTA SERIES PART 4 - FOUR FUTURE CONCERNS

A series of dams have already been built in the upper catchment areas of the Mekong Basin . The largest are within the area of China but other countries (Laos, Myanmar, Thailand and Cambodia) have also constructed dams along the main Mekong or on tributaries of the Mekong. More are planned. These dams have both positive and negative consequences. On the positive side they store and control water flow which assist during dry seasons. They have the capacity to reduce the level of flooding in the lower basin. Negative impacts include the displacement of people as river valleys flood behind the walls of the dams in developing lakes. Of greater concern is the siphoning of water away from the Mekong and the reduction of sand/silt flows into the lower basin. In Cambodia the Tonle Sap Lake will reduce in volume and the reverse flows into the lake could cease. This annual reservoir of water which arrives when the Mekong is in flood may not be released into the lower rivers and the delta. Other concerns focus on the rising salinity levels within the waters of the delta which will impact on on crop yields. Global warming is another concern. As sea levels rise the impact of oncoming waves will affect the coastline. Already some coastal areas are retreating inland - although other areas are showing advances seaward. The ecological value of mangroves as buffer zones between the salt water environment and the fresh water distributaries is recognised. The rate of illegal mangrove clearance is a concern. This section covers a local village approach to protect and add to mangrove areas. The unit is summarised with a map and recognition of the top 10 world deltas. Clues are given so that students can cover the activity. A blank world map is provided and if help is needed a completed answer sheet is provided. However, don’t be too eager to use this. Allow your students to work through the clues to see how close they can get to the correct and complete table and world delta placements.