A decision support approach for the selection and implementation of water harvesting techniques in arid and semi-arid regions

Water harvesting techniques (WHTs) improve the availability of water, which is essential for growing crops, especially in arid and semi-arid areas. A decision support approach can help in the selection of WHTs suitable under site-specific bio-physical and socio-economic conditions. This paper describes a participatory approach for the selection of suitable WHTs in watersheds in (semi) arid regions. It builds on a database of suitability indicators for WHTs, which was developed by integrating worldwide knowledge on their suitability. Once developed, the approach was applied on a case study for WHTs in the upper Geba watershed in northern Ethiopia. First, based on evaluation criteria and participants' scientific and local knowledge, a pre-selection of most promising WHTs took place in a multi-stakeholder workshop. Next, the suitability indicators and a GIS-based multi-criteria analysis (MCA) were used to identify suitable areas for these WHTs. The results of the MCA were presented to stakeholders during a second stakeholder workshop. At this workshop, a final selection of WHTs to test was made based on a participatory ranking of WHTs using economic, ecological and socio-cultural criteria. The MCA approach was validated by comparing the predicted suitable areas with the already existing WHTs in the watershed. This led to the result that 90% of the existing check dams and 93% of the percolation ponds were correctly identified by the approach. We conclude therefore that this approach can be successfully applied for the participatory selection of WHTs and the identification of suitable areas for their implementation. Given that this approach is based on the newly developed database of WHTs, it can be easily applied in other (semi) arid regions.