Coastal Village Bunds

ENTRY DATE: 23.04.2015 | LAST UPDATE: 23.04.2015

CATEGORIES:

  • Coastal Regions
  • Utilising and adapting natural surroundings

TECHNOLOGIES MATURITY:

Applicable immediately

Technology Owners:

  • Government
  • Implementing agencies e.g. GIZ
  • Community

Needs Address

Measures against erosion, storm surges, flooding, inundation 

Adaptation effects

  • Increases the resilience of coastal village communities against sea level rise and flooding by reducing the encroachment of flood water thereby reducing salinity intrusion
  • Protects agricultural land from flooding
  • Reduced flooding and salinity intrusion, enhances agricultural protection
  • Reduces mortality and injury resulting from flood events
  • Provides protection against strong winds during storms

Overview and Features

Earthen or clay built embankment structures constructed around a village to protect the community, homes and infrastructure from sea water flooding, storm surges and salinity intrusion. These can be 1-2 metres high and 2-3 metres wide, depending on requirements. The integration of shutters or gates into the design can enable the flow of water through the bund. A vegetation cover can be added to prevent erosion. The bunds are typically constructed with hard stiff clay, hard red earth and hard soil just behind the dunes.

Cost

  • Costs for equipment, human resources, maintenance, training
  • Costs dependent on location and materials used – locally sourced materials will incur less costs
  • The total costs for construction of a bund in India was USD 11,000 for pre-assessment, capacity building, design, materials and construction; maintenance is estimated at USD 50 per month E.g. The overall costs in the case of the Perumalpettai village, India, of this adaptation measure – including a local vulnerability and needs assessment, capacity building measures in the community, technical support as well as material and labour costs – amounted to approximately USD 10,000 (WeAdapt, n.d).
  • The cost of the bund construction varies depending on the location, length & height of the bund, availability of material etc.
  • Verification of the availability of soil by assessing the quantity of mud available in the proximity of 500 m of the construction site, otherwise costs increase.
  • Ensure skilled labour is available close to the location

Energy source

  • Human resources
  • Fuel for construction equipment

Ease of maintenance

Requires ongoing, but fairly simple maintenance

Technology performance

  • Coastal village bunds in India were constructed to protect villages and agricultural land from the impacts of SLR and flooding
  • E.g. The construction of a 1km long bund in Kaduvetti village in Tamil Nadu will stop the canal from flooding homes, fields, and fresh water supplies of the 273 residents of the village (AdaptCap, 2012a)

Considerations

  • Permission from land owners must be secured before construction of bunds
  • Pond or other catchment digging simultaneous with the bund construction can provide material for construction
  • In order to remain operative in the long run, several parts of the system require regular operation and maintenance (O&M). Regular O&M activities include (WeAdapt, n.d)
  • Verifying the constructed bund is intact
  • Implementing repair works on the bund
  • Taking care of the bund vegetation cover though planting and watering

Co-benefit, suitability for developing countries

  • Can provide ecological diversity
  • Can secure water resources by harvesting the water that overflows from canals and other water catchments lined by the bund
  • Creation/maintenance of freshwater resources
  • Bunds are managed and maintained by the community
  • Poorer communities may need support with initial construction design and costs, though operation and maintenance beyond this is relatively simple and affordable
  • Financial sustainability can be secured via community contributions
  • Can often be constructed with locally available material

Information Resources

AdaptCap, 2012a. Road Side Channel Bund Construction at Kaduvetti, Cuddalore District, Tamil Nadu. Available at: http://www.adaptcap.in/projects/kaduvetti-adaptation-project/ [07 April 2015]

AdaptCap, 2012b. Pond Renovation, Bund and Shutter Construction at Kadapakkam, Thiruvallur District, Tamil Nadu. Available at: http://www.adaptcap.in/projects/kadapakkam-adaptation-project/ [07 April 2015]

AdaptCap, 2012c. Backwater River Bund at Nadupalayam, Cuddalore District, Tamil Nadu. Available at: http://www.adaptcap.in/projects/nadupalayam-adaptation-project/ [07 April 2015]

GIZ. N.d. Strengthening of Bund, Coastal Plantation and Pond Renovation. GIZ Factsheet. Available at: http://www.hrdp-net.in/live/hrdpmp/hrdpmaster/hrdp-asem/content/e199/e11168/e32165/e32172/e32174/Vanagiri.pdf [21 January 2015]

WeAdapt, n.d. Preventing flooding through a coastal bund. Webpage. Available at: https://weadapt.org/placemarks/plain/view/1125 [21 January 2015]