The diversification of water sources reduces the pressure on the individual source and minimizes the danger of running out of water by bridging possibilities in times of scarcities. Connected to climate change rainfall patterns change and become more unpredictable. The altered infiltration rate into groundwater bodies as well as the possible lower capacity of stored water in reservoirs threatens the long term availability of water resources. Additionally the melting of glaciers and snow brings a loss in storage capacity and alters run-off regimes of rivers.
Often the water supply relies on only a few sources. Therefore, it is highly dependent on them and vulnerable on changes of the available amount of water in the source.
Possible solutions to diversify water sources depend on the regional and national circumstances and have to be well adapted. One possibility is the building of dams and reservoirs to store water in times of plentifulness. Furthermore rainwater harvesting creates additional amounts of available water. For agriculture in-situ rainwater harvesting is of special interest, as it includes land management strategies for better infiltration. Artificial recharge of underground waters enhances the capacity of aquifers. Additional underground storage is less prone of evaporation. The exploitation of new groundwater sources can also been applied. Desalination makes saline water sources, like sea or brackish water available for human use. The reuse of raw or partly cleaned waste water, especially in agriculture, further reduces the pressure on water resources.
GIZ (2012): Climate Change Adaptation in the Water Sector. Factsheet.