Managing the Chao Phraya River and Delta in Bangkok, Thailand: Flood Control, Navigation and Land Subsidence Mitigation

Abstract

Land subsidence as a result of the groundwater withdrawals in the Chao Phraya Delta in Thailand will be studied along with any successful remediation efforts. Most of the deltas of South East Asia are sinking for a variety of reasons. Thailand has national concerns related to land subsidence as a result of sea level rise, climate change, flooding, storm surges, skyscrapers, compaction, and groundwater extraction for rice paddies, shrimp ponds and the drinking water and household needs of approximately 15 million people living on the Chao Phraya Delta. The Chao Phraya River shoreline line is eroding and significant land areas and wetlands are being lost and becoming open water. Urban areas are periodically flooded and require earthen levees or floodwalls. The objective is to assess and mitigate land subsidence as a result of groundwater withdrawals for rice paddies, aquaculture, shrimp ponds, industry, drinking water and household needs of 15 million people living on Chao Phraya Delta in Bangkok. The impact of groundwater extraction and reduced sedimentation on land subsidence in the Chao Phraya Delta will be assessed and mitigation methods recommended. Lessons learned and successful remediation efforts in one Southeast Asia delta may or may not be applicable to other South East Asia deltas. There need to be mitigation methods identified to add sediment to existing Chao Phraya Delta wetlands. River water also needs to be injected deep into the underlying alluvial sediments in the delta. Navigation in the canal systems could be adversely affected by proposed massive Chao Phraya River water injections into the Chao Phraya Delta alluvial sediments underlying Bangkok.