Uncertainty with climate change is a big factor in accurately planning and preparing for WASH resilience. But planning only on changes in rainfall would be too simplistic, as water ''availability'' is not solely affected by climate change – population growth and changing water demand also contribute. Supply-side strategies (water volumes and availabilities) therefore need to be planned together with demand-side strategies (population growth, projected increases in demand). Lastly, greater rainfall intensity events may require some structures to be reduced (e.g. embankments, bunds) rather than increased.
===Definitions of drought===
[[Image:ClimateChangeDiagram.jpg|thumb|right|250px| Four Approaches to Drought. National Drought Mitigation Center (NDMC), University of Nebraska-Lincoln, USA.]]
[[Image:DroughtMap.jpg|thumb|right|250px|Regions of drought recorded between 1979 and 2008, where drought events are identified as three consecutive months with less than 50% of rainfall as compared with the average.]]
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|[[Image:water stress.jpg|thumb|center|300px|Water stress in relation to population. Figures are in m3 of water per person per year for 2008. Source: [http://www.fao.org/nr/water/aquastat/globalmapsdata/query/index.stm html?lang=en FAO Aquastat database.]]]
|[[Image:WaterAvailabilityChangeMap.jpg|thumb|center|300px|Change in water availability compared with average 1961-1990 (%). 2050 based on IPCC scenario A1.]]
|[[Image:water scarcity map.jpg|thumb|center|300px|Areas in orange lack sufficient water resources to meet basic needs, while purple has water available but lacks the financial and/or technical resources to access the water. Source: USAID, 2010.]]
===Drought links===
====Climate change====
====Groundwater, wells, infiltration galleries, boreholes====
# Danert, K.; Armstrong, T.; Adekile, D.; Duffau, B.; Ouedraogo, I.; Kwei, C. (2010) [http://www.rwsnrural-water-supply.chnet/en/documentationresources/skatdocumentation.2010-08-23.4523209156details/file 128 Code of Practice for Cost Effective Boreholes.] RWSN, St. Gallen, Switzerland. Code of practice for effective borehole drilling.
# Roscoe Moss Company (1990) [http://books.google.co.uk Handbook of ground water development.] John Wiley & Sons, USA. How to deepen existing boreholes.
===Acknowledgements===
* CARE Nederland, ''Desk Study Resilient WASH systems in drought prone areas.'' October 2010.