Analysing watersheds with 3D models

To better engage and involve farmers in the analysis of their land, we are testing use of a 3D model. This tool is used for local  management of resources and has already had success in other countries. The experiment was conducted on the watershed of the village of Adda, where we are putting in place management activities to protect the Hamkambui water source. We plan to also use this tool on the watersheds in the Outsa and Ouzini areas.

 

  • Building the 3D model

The first model shows the Adda site, a downstream watershed for which a capture system and an irrigated zone have just been built to allow farmers in the area to invest in fields lower down the slopes.

To build the model, we prepared a map showing contour lines to the required scale from SRTM data to a geometric accuracy of 30m. This map was used to create the different altitudinal layers of the model.

The final model, made with several layers of cardboard and a plaster surface, occupies an area of 60 cm x 40 cm. It shows the Hamkambui watershed to a scale of 1/3000 (1 cm = 30 m).

In addition to the contour lines, some topographic elements were painted on the model to help farmers to get their bearings: roads, the Adda football field, the capture system, hedges and major gullies.