Description
Boreholes and tubewells are important adaptation technology measures for providing a domestic water supply during times of water shortages and drought. They extract freshwater from subsurface or deeper groundwater aquifers. The approach can include both creating new boreholes and tubewells (for example as a drought response measure), or deepening or rehabilitating existing ones.
Implementation
Tubewells are relatively easy to construct and often can be installed using a hand auger. The main component of a tubewell is a narrow screened tube, pipe or casing that is driven into a subsurface aquifer. Boreholes are similar to tubewells, but differ in that they are used to access deeper and more difficult to tap water resources, as well as requiring bedrock penetration. Once constructed, both types of wells would require a pump to transport water to the surface for domestic or irrigation purposes. Pumping tools include hand-operated pumps, diesel pumps, electric pumps and solar driven pumps. Repairing already existing boreholes (for example by fixing pump mechanical failures) can be an inexpensive way to create water access without having to drill new wells. This usually costs far less than establishing new holes. Borehole and tubewell siting should consider soil type, existing water point locations, proximity of potential contamination sources, population distribution, and area water availability (including water table depth). In areas prone to flooding, the wells can be constructed on elevated platforms to avoid contamination during flood events. To maximize benefits, groundwater surveys should be conducted. If the borehole or tubewell is used as a drinking water source, precautions should be taken to ensure that water quality is acceptable.
Environmental Benefits
- Relieves pressures on surface water sources, reducing risks of pollution and degradation.
Socioeconomic Benefits
- Provides freshwater for domestic and other uses in times of drought.
- Produces high quality water, reducing health risks that may occur from use of surface water sources.
- Helps avoid interruption of significant socioeconomic activities during dry periods, for example when used for irrigation.
Opportunities and Barriers
Opportunities:
- Increased diversification of water sources provides for more water but also increases water supply resiliency.
Barriers:
- Requires pumping and associated energy supply (and costs) for larger volumes, though solar water pumps are becoming increasingly viable
- Requires knowledge of local geological conditions and assessments of chosen drilling sites
- Poorly coordinated well development can cause a groundwater table decrease and create risk of over-abstraction
- In areas with high climate variability (floods and droughts), tubewells and boreholes are at risk of being contaminated during flood events.
Implementation considerations*
Technological maturity: 5
Initial investment: 1-2
Operational costs: 1-2
Implementation timeframe: 1-2
* This adaptation technology brief includes a general assessment of four dimensions relating to implementation of the technology. It represents an indicative assessment scale of 1-5 as follows:
Technological maturity: 1 - in early stages of research and development, to 5 – fully mature and widely used
Initial investment: 1 – very low cost, to 5 – very high cost investment needed to implement technology
Operational costs: 1 – very low/no cost, to 5 – very high costs of operation and maintenance
Implementation timeframe: 1 – very quick to implement and reach desired capacity, to 5 – significant time investments needed to establish and/or reach full capacity
This assessment is to be used as an indication only and is to be seen as relative to the other technologies included in this guide. More specific costs and timelines are to be identified as relevant for the specific technology and geography.
Sources and further information
- UNEP-DHI Partnership- Boreholes and tubewells
- CABI (2015). Climate Change Challenges and Adaptations at Farm-level. Case Studies from Asia and Africa, Edited by N P Singh, Principal Scientist (Economics). ICRISAT, India, C Bantilan, Director (RP-MIP). ICRISAT, India, K Byjesh, Consultant. ICRISAT, India, S Nedumaran, Scientist (Economics). ICRISAT, India, CABI Climate Change Series, November 2015
- ClimateTechWiki (2017). Domestic water supply during drought, http://www.climatetechwiki.org/content/domestic-water-supply-during-dro…
- De Lopez, T. T. (Ed.), Elliott, M., Armstrong, A., Lobuglio, J., & Bartram, J. (2011). Technologies for Climate Change Adaptation - The Water Sector. Roskilde: Danmarks Tekniske Universitet, Risø Nationallaboratoriet for Bæredygtig Energi. (TNA Guidebook Series). Available at: orbit.dtu.dk/files/7689720/TNA_Guidebook_AdaptationWater.pdf
- UNFCCC. 2014. Technologies for Adaptation in the Water Sector. TEC Brief #5, United Nations Framework Convention on Climate Change.
- WaterAid (2012). Handbook: Climate Change and Disaster Resilient Water, Sanitation and Hygiene Practices, December 2012, WaterAid in Bangladesh
- WaterAid Bangladesh (2006). Step by step implementation guideline for tubewells, Dhaka, May 2006. Available at: www.wateraid.org/~/media/Publications/tubewell-guidelines-rural.pdf
