The Development of a flood forecasting system for the Sistan plain in Iran

The Sistan plain is located in Sistan-Baluchistan in the south-east of Iran, bordering Afghanistan. The plain is home to approximately 350,000 people and supports 230,000 ha of irrigated agriculture fed by distributaries of the Hirmand River. The Hirmand River drains a 178,000 km2 catchment that is primarily located in Afghanistan. The Sistan plain is regularly affected by devastating flood events that usually result from the sudden melting of snow covering the Kuh-i-Baba mountains in Afghanistan several hundred kilometres away from the Sistan Plain. There is often little warning of these floods in Iran because they usually occur under “blue sky” conditions. A number of mitigation measures have been implemented by the Iranian Government to reduce the damage to infrastructure and the risk to life from major floods. This paper describes these measures including a prototype flood forecasting system for the Sistan plain based on the use of a weather forecasting model and the estimated snow cover on the Kuh-i-Baba mountains in Afghanistan.