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Rehabilitating small-scale piped water distribution systems

Technical note 4 on drinking-water, sanitation and hygiene in emergencies

Step 1: Assess the extent of the damage

The damage caused by natural disasters to networks for piped drinking-water distribution can be widespread and extensive. It can range from minor breaks to complete loss of whole sections of the system. A systematic survey of the entire network is the only way of identifying the true extent of the damage. This may not be possible in an emergency where the priority is to re-instate a basic level of supply. This technical note examines these priorities and the process of rehabilitating small-scale piped water distribution systems.

Steps of rehabilitation

The first priority is to repair major breakages in the system. This will allow the re-instatement of a supply but with the knowledge that much of the water entering the network will be lost through breaks not yet fixed. Once the emergency supply is in place, work can begin to identify and repair smaller breaks. Figure 4.1 shows the steps for repairing major breaks in pipe networks.

Step 1: Assess the extent of the damage

Identify local staff with knowledge of the distribution system as their involvement in the rehabilitation will make the job much easier. Obtain any available drawings of the distribution network layout, including information about the size of pipes and positions of fittings such as valves and washouts.

At the very least, obtain a plan of the community showing main roads and important buildings. For many parts of the world, suitable maps can be freely downloaded from the Internet. Inspect the whole of the piped network and mark on the plans the positions of all major damage, its nature (for instance whether it is a broken valve, a fractured pipe, a lost pipe section) as well as the type of pipe affected (see Figure 4.3).

Focus on visible damage. It is likely that there will be damage underground but this can be dealt with later. Check the local stores to see if there are enough spare pipes and fittings of the correct size, and materials and equipment to begin the repairs. If not, order these immediately.