Disasters can befall any society and can effect any community.  Disasters include both natural and human induced crises such as floods, droughts, earthquakes and war.  Often natural disasters are exacerbated by human activities such as increased risks and consequences of floods due to poor land-use practices which are themselves the results of poverty, the pressure of increased population, misguided public policy and a host of other causes.  

Whenever disasters strike there is an immediate objective of minimizing the loss of life and damage to property as a direct consequence of the disaster.  This is followed the need to provide relief to the survivors of disasters to ensure that there is no secondary threat of disease and loss of life due to the breakdown of health services and basic infrastructure.  There then follows the process of reconstruction and development in order to re-establish the communities, to reduce dependency and to mitigate against the recurrence of the disaster.

Water plays a critical part in most disasters and relief efforts.  This is true in two main forms:- 1) the role of water in the cause of disasters, and 2) the role of water in relief and reconstruction.  

1. The most obvious role of water in the cause of disasters is in the event of floods (too much water) and in droughts (too little water).  The less obvious facts relate to root causes of these disasters where human activity is often a factor which could be addressed through improved public policy or is the result of poor policy.  These indirect causes or exacerbating factors may be very varied and include water resources management policies, agricultural policy, population development and settlement policies, environmental protection policy (or the lack thereof), industrial and economic development policies etc..  The possible implications of policy in the cause of disasters and specific mitigation measures need to be considered during the process of policy formulation. 

2. Most large scale disasters result in the disruption of the provision of basic services.  It is critical to re-establish the provision of water supplies and safe sanitation services, (as well as electricity, access to utensils, storage facilities etc.) as soon as possible.  The threat to the lives and well-being of victims due to disease caused by inadequate or contaminated services may be greater than the threat of the original disaster.  For these reasons, after the immediate rescue phase of disaster relief, relief measures often concentrate of the provision of emergency relief supplies and the restoration of basic infrastructure.  As a result many disaster relief organisations now have sections which specialise in the provision of emergency water supply and sanitation services.

An example of this is the International Committee of the Red Cross - see a very useful article entitled Water and habitat: introduction.  

Also see the page on Conflict