Topic
- Aquifers 50
- Water--Purification 46
- Dams 34
- Climate 33
- Drinking water 33
- Precipitation (Meteorology) 33
- Wells 31
- Sewage--Purification 30
- Resource allocation 27
- Water-power 27
- Technical assistance 25
- Soils 24
- Population 23
- Reservoirs 22
- Industries 21
- Salinity 21
- Tiberias (Israel) 16
- Recycling 15
- International regimes 13
- Rivers 13