Why indigenous water systems are declining and how to revive them: A rough set analysis

For many centuries, rainwater harvesting (RWH) was the main source of water in many ancient countries. However, over the last four decades, its use has been declining steadily. RWH structures fell into disrepair and were abandoned or were only occasionally used. Taking Sana'a Basin in Yemen as a case study, we examined the underlying factors for the decline and explored ways to reverse it. We interviewed 100 farmers and 65 experts and visited 22 RWH systems, both abandoned and still in use. We used rough set analysis to analyze RWH systems data. The overall results showed that the government plays a crucial role in the operational status of the RWH systems. However, the government's rhetoric on the importance of investing in traditional RWH, very few projects were actually implemented or maintained. In contrast, access to groundwater was heavily promoted making it the preferred water source. However, the water table became depleted and there was a dependency on diesel. Other socioeconomic factors including ownership, limited capacity of RWH systems, the availability of imported food, and rural-urban migration were other secondary reasons for abandonment. Without a shift in government support from groundwater to rainwater harvesting, this long-term decline is likely to continue. •Indigenous RWH systems are in a state of decline.•The role of government is a major variable in the declining of RWH systems.•Availability of water and food alternatives also affected the use of RWH systems.•During crises and extreme water shortages, people appreciate indigenous RWH systems.