The importance of preservation of ground water level is as important. For this the suggestion of Ms Komalavally to harvest the rain water is very important. She has mentioned the other benefits like helping in having a check, though minimal, on atmospheric warmth. This harvested water can be used for horticulture, Floriculture etc. As suggested in her comment most houses will have well and can be used to harvest the water. Since Kerala gets plenty of rain, The wells might already be getting food quantity of water. So the families can go for a mini well or pond. This measure of harvesting rain water will definitely help in climate control, ground water level maintenance which will again have a cyclic effect to get good rain in the next season.
Ramanathan A R