3.4 Climatic considerations

Climate will have a major impact upon a water supply system. From an emergency point of view, constructing systems during the summer months in countries that experience winter and summer extremes can prove extremely challenging. The issue of freezing is the most obvious one to address and plan for.

The Tajik refugees came into Northern Afghanistan during December 1992. Temperatures were below freezing and the wind chill made it excruciatingly cold. Burying the pipes was possible and so they were not the main concern. It was the exposed parts of the distribution network, such as the small-diameter pipes to tapstands, gate valves and pumps that were most vulnerable. Large bodies of stored water are less of a problem than smaller quantities. Ways can be explored for burying storage tanks, or providing some form of insulated cover. Roofs over storage tanks need to be designed to withstand snow. Chlorine becomes far less effective with reduced temperatures and contact times therefore need to be significantly increased (see Annex 7). Consideration should also be given to how far people have to walk to collect water. Will this exposure time be a risk to them? What about snow and ice on the paths? This is particularly relevant in hilly areas.

Emergency programmes in the former Soviet Union and the former Yugoslavia have also had to deal with these problems.