Water Management

Water Management

1. increasing water consumption

   • growth of world's population
   • economic development
   • more irrigation to produce food

2. factors affecting water availability

   • geology
     • water in permeable rock
   • climate
   • pollution
   • over-abstraction

3. strategies to increase water supply

   • diverting water
     • stored in alluvial salts
       • eg Oklahoma, USA
   • dams and reservoirs
     • advantages
       • control river flow
       • prevent flooding
     • disadvantages
       • expensive
       • displacement of many
       • reduce flow downstream
   • desalination
     • remove salt from seawater
   • water transfer
     • eg Lesotho Highland Water Project
       • 40% water in R. Segu transferred to R. Vaal
       • advantages
         • Lesotho
           • 75% GDP
           • covers all hydro-electric requirements
         • South Africa
           • safe water for extra 10%
           • reduces acidity of R. Vaal
       • disadvantages
         • Lesotho
           • 30 000 displaced by 1st two dams
           • destruction of wetland
           • corruption
         • South Africa
           • US$4 billion
           • 40% lost through leakages

4. sustainable water supply

   • eg Wakel River Basin Project
     • issues
       • over-irrigation
         • waterlogging and salinisation
     • increasing supply
       • taankas
         • underground storage systems
         • water from roofs
       • johed
         • earth dams
       • pats
         • irrigation channels to fields
   • groundwater management
     • abstraction balanced by recharge
   • using grey water
     • in Jordan, 70% of irrigation is grey water
   • recycling
     • eg in nuclear power plants

5. impacts of water insecurity

   • waterborne diseases
   • water pollution
     • eg River Ganges, India
       • 1 billion litres of raw sewage enter river each day
       • toxic chemicals and pesticides
   • food production
     • agriculture uses 70% of water
   • water conflict