Controlled Sedimentation

Needs Address

Measures against erosion, storm surges, flooding, inundation

Adaptation effects

• Provides a drainage facility
• Increased crop production

Overview and Features

Controlled sedimentation to balance sedimentation transport allowing controlled flooding or sedimentation accumulation enabling stability of coastal surfaces. Sediment controls are usually employed together with erosion controls, which are designed to prevent or minimise erosion and thus reduce the need for sediment controls. Sediment controls are generally designed to be temporary measures, however, some can be used for storm water management purposes. E.g. Pilot testing of raising coastal land levels by means of controlled sedimentation in the Sundarbans, Bangladesh (Agrawala, et. al. 2003). 

Cost

• Equipment for guiding sediment loads
• Labour

Energy source

• Fuel etc. for construction equipment
• Human resources for constructions and maintenance

Ease of maintenance

Require continuous maintenance activities and attention according to changing ecological environments, anthropogenic activities and sediment cycles. 

Technology performance

• Have enabled increased river drainage
• Has helped to maintain natural coastal protection ecosystems such as mangroves

Considerations

Requires comprehensive management systems that incorporate understanding of inter-system processes to ensure outcomes do not imbalance ecosystems further upstream

Co-benefit, suitability for developing countries

• Effective flood drainage enhances agricultural productivity 
• Post project appraisals for the Khulna-Jessore Drainage Rehabilitation Project have indicated that this approach is locally-acceptable

Information Resources

Agrawala, S., Ota, T., Ahmed, A.U., Smith, J. and van Aaist, M. 2003. Development and Climate Change in Bangladesh: Focus on Coastal Flooding and the Sundarbans. Organisation for Economic Co-operation and Development. Available at: http://www.oecd.org/env/cc/21055658.pdf [04 December 2014]