As part of the implementation of the Comprehensive Resilience Building in Chimanimani and Chipinge project, UNESCO in partnership with the Catholic University of Leuven and the University of Zimbabwe embarked on a field trip on landslides assessment from the 5th to the 13th of July 2021. This assessment will be followed by further field research measurements until the end of July 2021.
The aim of the field assessment was to further assess the landslides that occurred in Chimanimani and Chipinge particularly linked to Cyclone Idai in 2019. It was initiated after the Catholic University of Leuven had mapped out approximately 20,000 active landslides in the two districts (mainly connected to the Cyclone Idai event) using remote sensing data.
The Cyclone Idai disaster uncovered that the area is susceptible to devastating landslides, which prompted UNESCO to engage local and international experts to develop landslide susceptibility and risk maps which could be useful in land use planning and to direct land and ecosystem restoration and slope protection works. Through extensive assessments and research, the initiative aims to better understand the drivers of these destructive events and to identify pathways and interventions for mitigation of their impacts, such as the development of a landslide early warning system.
Over the past field research, the experts identified two possible landside mechanisms that occurred: classical slope failure and large debris flow. In the Rusitu area, deeply weathered soil had become saturated with water and failed. The failures are possibly associated with the steepness of slopes and land cover loss due to deforestation, which may have been worsened by the excessive rains. Unsustainable farming methods, including riverbank farming which are being practiced in the area could have also intensified the landslides. The team also noticed that there was a potential linkage between the land use and the landslides as areas with dense forest cover were less affected, more so in areas with indigenous forests. It was also noted that farming lands where conservatory farming was practiced were less affected, however, more studies are required to concretise these preliminary findings. In their first field-based insights, the experts indicated that there is a need to predict the runout lengths of (combined) landslides.
A post field assessment media briefing was held on 12 July 2021, to share information on the progress, findings of the field assessment and the way forward in the development of high-resolution landslide zonation maps for Chipinge and Chimanimani systems. The online briefing, which was attended by local journalists, also aimed to communicate the significant role of journalists to sensitize the general public at large on the impact of natural disasters, particularly the risk and devastation of landslides in vulnerable areas in Zimbabwe. Speakers who presented and shared insights into landslides included Prof. Martiale Zebaze Kana, Senior Programme Specialist at UNESCO (in representative of Prof Hubert Gijzen, Regional Director and Representative for Southern Africa); Mr Djibrilla Mazin, the Country Manager at UNOPS; Mr Nicholas Callender, a Disaster Risk Management Specialist and Task Team Leader for ZIRP at the World Bank; Mr Lameck Betera, the Acting Deputy Director from Department of Civil Protection; Dr Koen Verbist, Programme Specialist at UNESCO; Dr Matthias Vanmaercke, an associate professor at the University of Liège; Dr Maideyi Lydia Mabvira- Meck, a senior lecturer and Staff Development Fellow in the Geology Department at the University of Zimbabwe.
Landslides disaster risk reduction is one key component of an initiative being led by UNESCO on Comprehensive Resilience Building in Chimanimani and Chipinge Districts under the World Bank funded Zimbabwe Idai Recovery Project (ZIRP). The overall objective of the initiative is to reduce the vulnerability of communities in the Chimanimani and Chipinge Districts to natural disasters, such as floods, droughts and landslides; and to enhance water resource management as well as ecosystem services in response to the uncertainty of future climate change.