Simple measures like preventing the rainwater from leaving the premises can prevent flooding of the streets. The water can be directed for recharge. Dual purpose wells, for withdrawal as well as for transfer of surface water into aquifers, can be constructed. Water harvesting can supplement wastewater recycling. Using soil-aquifer treatment systems it is possible to clean up wastewater for recharging and other purposes.
Urban lakes are in a deplorable condition in almost all urban towns and cities.
To restore them to their past glory biological remediation can be availed of. Using a combination of physical and biological filters, drinking water can be made safe. In rainfed agricultural areas in semi-arid regions, production can be boosted by simple technologies that capture the rain and retain it in the soil. Even one supplementary irrigation makes a significant difference in yields. It is important to study traditional systems.