Purpose & Audience

This guidance tool seeks to increase knowledge among World Bank teams of nature-based solutions (NBS) for landslide risk management, particularly at the landscape scale. A recent study found that in some areas landslides are nearly 6x more likely to occur on non-forested lands than on forested lands, and estimated that it was 16 times more cost-effective to promote forest corridors (conservation or reforestation along roads) than to pay for the expected landslides damages. While one study cannot be generalized globally, research suggests that NBS have an important role to play in reducing landslide risk and protecting people and assets. Further, NBS confers multiple co-benefits for people, biodiversity, and the environment through leveraging forests and vegetation to reduce risk. The Sendai Framework for Disaster Risk Reduction (2015-2030) has recognized NBS as a strategy that can reduce disaster risk across various disasters and at the same time increase climate adaptation and community resilience. Understanding NBS as a potential solution to manage disaster risk is growing, particularly for mitigating floods and coastal erosion, but application to landslide risk is more limited. This guidance tool seeks to fill this knowledge gap by collating information about landslide risk assessment and providing examples of how NBS can be integrated into the landslide risk assessment and management process to prioritize its use.

Definition of Nature-based Solutions:

This guidance note adopts the definition of NBS used in earlier World Bank work on the topic (

World Bank 2019, Integrating Green and Gray: Creating Next Generation Infrastructure

): NBS refers to “actions to protect, sustainably manage, and restore natural or modified ecosystems that address societal challenges effectively and adaptively, simultaneously providing human well-being and biodiversity benefits.” (

Cohen-Shacham et al 2016

as cited in

World Bank 2019

) Green infrastructure is a subset of NBS, “…that intentionally and strategically preserves, enhances, or restores elements of a natural system to help produce higher-quality, more resilient, and lower-cost infrastructure services.” (

World Bank 2019

)

The goal of this guidance tool is to increase awareness among World Bank teams to methodologies that exist for landslide risk assessment, and NBS to manage identified risks. World Bank activities are both affected by landslides and other types of geohazards and, if not properly implemented, can contribute to increased landslide and geohazard risk. Specifically, landslides interface with forestry, agriculture, water, transportation, housing and urban sectors, among others, both increasing risks of loss of life and economic damages to these sectors as well as being impacted (potentially triggered) by activity within these sectors. Identifying and managing landslide risk is critical to the success of development projects across multiple sectors, and to the lives and livelihoods of the people who are meant to benefit from development activities.

Specifically, the guidance seeks to help World Bank teams to:
Identify

Identify suitable landslide risk assessment methods for their project

Understand

Understand how NBS can be integrated into the landslide risk assessment process and how to prioritize areas for NBS implementation to manage identified risk

Assess

Assess the level of effort and relative cost of landslide risk assessment at different scales and varying levels of sophistication in order to match risk assessment and management activities to project goals, timeline and budget

This guidance tool seeks to answer the following question, raised through numerous consultations with Bank staff, development partners, scientists, and experts working in the field of landslide risk assessment and NBS:

  • I have a landslide-prone project area. How can I understand the landslide risk and methods available to reduce landslide risk?

  • How can I advise my client on using gray vs. green solutions?

This guidance tool provides insights to these questions through answering the following sub-questions:

  • What are the types and characteristics of landslides?

  • How do we know when a landslide might happen and what potential impacts may be?

  • What is landslide risk assessment modeling and what outputs can I expect?

  • What are the relative pros and cons, and associated costs, of landslide risk reduction measures?