Check Dams

Needs Address

Reduced vulnerability to landslides

Adaptation effects

Reduces the impact of landslides upon communities in mountainous regions

Overview and Features

Check dams can be constructed from different material types, e.g. bamboo, gabion, stone. Their function is to reduce the flow of debris, such as mud, stone, sand, gravel, boulders, and water from mountain side. The two types of check dams, closed type and open type, are distinguished by the necessity to remove sediment artificially or not. Open check dams can retain their trapping capacity without the need for manual removal of sediment. Check dams are often implemented in tandem with soft prevention and reduction methods.

Figure 1: Gabion Check Dam (Source: Sthapit and Tennyson, n.d.)

Figure 2: Bamboo Check Dam (Source: Sthapit and Tennyson, n.d.)

Figure 3: Bamboo with Loose Stone Check Dam (Source: Sthapit and Tennyson, n.d.)

Figure 4: Different Dam Types for Reducing Debris Flow (Source: Lien, 2003)

Cost

• Costs of materials – locally available materials more cost-effective
• Cost of labour
• Cost of maintenance

Energy source

• Human resources
• Fuel for construction equipment

Ease of maintenance

• Continuous maintenance necessary, particularly after surges of debris
• Closed types need ongoing manual removal of sediment

Technology performance

• Have been used for many years as a principal method of increasing sediment transport and debris flow control
• Closed check dams have in the past failed to effectively catch the debris flow, leading to a preference for open check dams in some places
• Sediment trapping capacity is more effective in a grid-type check dam

Considerations

• The planning of check dams must incorporate the consideration of various scenarios and involve the evaluation of the hydrological, hydraulic, sediment size, and topographical characteristics of the local context
• The check dam must be built with adequate storage capacity to store the flow of debris

Co-benefit, suitability for developing countries

• Secure life support in communities in the mountainous regions.
• Needs careful assessment of the impact before building (large scale dam).
• Can be community-constructed and owned
• Can be constructed from locally available materials

Information Resources

Larcher, M. and Armanini, A. 2000. Design Criteria of Slit Check Dams and Downstream Channels for Debris Flows. International Workshop on the Debris Flow Disaster of December 1999 in Venezuala.

Lien, P. 2003. Design of Silt Dams for Controlling Stony Debris Flow. International Journal of Sediment Research, Vol. 18, No. 1, 2003, pp. 74-87

Shreshta, B.B. et al. 2008. Numerical Simulation on Debris-Flow Deposition and Erosion Processes Upstream of a Check Dam with Experimental Verification. Annuals of Disaster Prevention Research Institute, Kyoto University, No. 51B.

Sthapit, K.M. and Tennyson, L.C. n.d. Bio-engineering erosion control in Nepal. FAO. Available at: http://www.fao.org/docrep/u1510e/u1510e04.htm [28 December 2014]