Dear  Salim Adam Although the ...

Dear  Salim Adam 

Although the subject of water supply is well covered in many emergency manuals, there are additional factors which will affect the provision of fresh water for domestic supplies in conditions where the ambient temperature is close to or below 0°C. Chemical reactions are slower at low temperatures and biological processes also take more time. The physical properties of water, in the form of water, ice or snow, are temperature dependent, therefore affect processes involved in supplying water and the range of technology that can be used.

First, in mountainous areas, water emerging from springs is likely to be quite cold already, having originated higher up the slope. This increases the likelihood of the water freezing during a cold spell. If outlets from a spring boxe do freeze up, the resulting back-pressure may cause subterranean water flow channels to alter their course, causing the spring to emerge at a different place! It is essential to guard against freeze-ups by covering spring boxes with an insulating layer of soil, of a depth equivalent to the depth of maximum winter frost penetration in the ground, so that water in the spring box is never cooled to below 0°C. A thickness of 0.75m to 1m of soil cover provides adequate insulation for most situations.

  Secondly, building spring boxes in scree is very likely to cause problems. In scree subterranean flows can alter course periodically, causing the spring to emerge at a different place. The spring protection then has to be moved to the new location where the water emerges from the ground, or new protection facilities built. Scree movements are also likely to damage spring boxes, necessitating continual maintenance. If it is impossible to avoid scree, use local materials, as it is very likely that the spring box will have to be replaced periodically.

1. Locate pumps in a pump house to help prevent water freezing inside.
2. Ice is likely to form on concrete aprons around boreholes and wells. Care should be taken to provide good drainage, and to encourage people not to splash water around if at all possible.

Lift pumps

These are distinguished from suction pumps by the location of the pumping cylinder, which is submerged below the water level in the borehole. Lift pumps are normally used when the dynamic water level is more than 7-8m below ground, making suction impossible. Lift pumps make sense in cold areas precisely because the working parts of the cylinder will always be underground, where they will be insulated from the cold. Above-ground pump parts can be protected by making a small diameter ‘weephole’ in the riser pipe just above the cylinder (either below groundwater level or above the water table at a depth where freezing will not occur). Water slowly drains out of the above-ground section when the pump is not being used, reducing the likelihood of water freezing in the aboveground pump sections. This causes a small loss in the pumping efficiency, although being below water level the cylinder needs no priming.