Geotechnical Impacts of August 2018 Floods of Kerala, India Event: August 2018

The Southern State of Kerala in India experienced extreme rain in August from the 1st to the 20th, 2018. The state received a cumulative rainfall of 771 mm during that period, which is 140% more than the normal for that time period. The extreme rain event led to flooding and landslide hazards leading to 483 deaths and severe destruction of property.

The NSF sponsored GEER team members (Dr. Thomas Oommen, Michigan Tech; Dr. Richard Coffman, University of Arkansas) in coordination with colleagues from University of Kerala (Dr. Sajinkumar K.S. & C.L. Vishnu) conducted a reconnaissance study to gather perishable data. The study was carried out from September 4th to 9th, 2018. The team traveled to three districts that have been affected by the disaster (Alleppey, Idukki, & Ernakulam).

The preliminary finding indicates that the failure of bund in Alleppey further aggravated the flooding and led to the slow recession of flood waters. The flooding in Alleppey has also led to the differential settlement of several buildings. In the district of Idukki, several landslides were identified near recent construction. The alteration in the topography for construction has led to more infiltration and increased groundwater levels during the rain event that have led to these landslides. In addition, soil piping and subsurface drainage channels were also frequently identified at landslide sites in Idukki. This is a preliminary report that the team has produced. A detailed report will be submitted in 3 months.