Upper River Erosion and Landslide Protection Planning: An integration of erosion and landslide hazard mapping using GIS and remote sensing and the value chain approach

By: Pham Huu Ty (Vietnam)



Learn about the Project

A decision support model assisted by GIS and remote sensing is very useful, but it may be insufficient to formulate an effective planning without involving the participation of local people. • The aim of this research is to design and implement a framework for erosion and landslide protection planning at community level in central Vietnam.

Findings

1. Mapping erosion and landslide

  • Three kinds of maps have been produced: (1) upland soil erosion map, (2) riverbank erosion map, and (3) landslide map
  • Riverbank erosion: increasingly severe, huge losses of areabale land, risky for living areas – especially for several resettlement sites
  • Upland erosion: occurred mostly on plantation forests with poor covers (young Acacia forests), rill and gully erosion are clear on the field, but not easy for local people to distinguish with landslide
  • Landslide map: created by combining models and participatory process, AHP method used to integrate local perception, AHP expertises from Dr. Chuong (one of AHP experts), and then simulated in ArcGIS software. Map accuracy is quite well, but landslide in Ta Rinh watershed is very severe in which most accurred in several communes. However, many areas are prone to be slided under changing environment and climate.

2. Results from Lo O tree investigations

  • One map of Lo O distribution is produced
  • One report of Lo O value in technical and economic and it areas. The price of Lo O is significantly increasing every year with very potential markets for toothpicks, chopsticks, hats, and other handicrafts.
  • A map is produced to show potential areas which could be suitable for Lo O to plant in terms of local perception and a set of criteria.
  • Lo O tree is selected by local authority and person and a good measure to prevent and mitigate erosion and landslide in the future, but it needs time to grow (5 to 7 years) enough to protect riverbank erosion and landslide.

3. Climate change information and its relation to erosion and landslide

  • Climate change is clear in the study site with higher rainfalls, more frequently floods with shorter concentration time and more damages, lower rainfall in the dry season. Additionally, local staffs are aware of this issue from the Government, NGO projects, and media.

4. Erosion and landslide protection planning

  • Suitability evaluation models for selecting areas to plant Lo O tree were developed. These models come from a set of criteria and then built in ArcGIS thematic layers, and then run by Calculator model. AHP is the method used to estimate suitability indices.
  • After that, suitability indices were checked with local people and validated in the field. There are 4 levels of suitability (very, moderate, low, and none), validations show that areas specified to plant Lo O trees are acceptable in practice.
  • Protection planning maps have been built and shared with local communities. Now, we are finalizing maps and making a full protection report sending to A luoi district and SIRCA.

5. Monitoring the Lo O plantation

  • Lo O tree is easy to plant and local people has very good experience on planting and taking care of them
  • The process is still on-going, but we see that Lo O is only one of measures to prevent erosion and landslide and it is required a long period to have it grown enough. Therefore, we need different options to stop very severe erosion areas currently.

PI’s Current Progress (To be made available soon)