Slide evaluations in El Salvador

The Hurricane IDA which hit El Salvador on 8th November led to a series of landslides and flooding. On assignment from UNDP and the World Bank, NGI has contributed to finding mitigation and safety measures to reduce the risk for similar incidents in the future.

The Hurricane IDA which struck El Salvador in Central America 8th November this year caused extreme precipitation (317 mm in 7hours). This led to a series of landslides and floods in the many steep hills of El Salvador. The most severe landslides occurred from the volcano San Vicente, about 50 km east of the capitol, San Salvador, where one village was exposed in particular. Roughly 60 dwellings were demolished by the landslide debris and more than 100 people were killed.

An estimated 200 to 250 casualties resulted from landslides and floods after the Hurricane IDA in El Salvador. Many roads were destroyed and utility lines were broken. Current estimates indicates that the damages add up to about US$ 500 mill.

Actions to reduce risk
NGI was contacted by the World Bank to assist a commission led by the UNDP (United Nations Development Program) with scientific evaluations to what caused the landslides and to suggest actions to reduce the risk for similar incidents in the future.

Frode Sandersen, one of NGI's experts with broad experience from a variety of geohazards, had an on-site inspection in the affected areas in the period 22-29 November this year. The work was done in close cooperation with MARN, the local authority unit responsible for such incidents in El Salvador. NGI helped build up competence and know-how at MARN from 2002.

Suggestions to mitigation and safety measures for the village most severely struck by the slides were made. These include construction of a 850 metres long and 10 metres high embankment which will lead future slide masses and debris away from the dwellings. The commission will present their report to the authorities in El Salvador on 5th December 2009.