Combating water scarcity through roof water harvesting: planning and design with stakeholders' perception in Sikkim (India)

Sikkim is one of the constituent states of India endowed with huge water resources. However, due to steep terrain and non availability of ground water aquifer, water conservation is a challenge. The water received as rainfall drains away through the steep terrain in the deep valleys thereby creating a water stress after withdrawal of the monsoon. To overcome such situation a study was undertaken to design a suitable rain water harvesting system for the state. To design a suitable water harvesting system we estimated the water demand of the end users, assessed the water availability during non rainy period and designed the volume of storage structure. The study revealed that more than 80% of the respondent experienced water stress during the period December to March. The average daily water demand of individual household was observed to be around 400 litres. The rainfall pattern indicated that 90% of the rainfall is concentrated during 6 rainy months. In average 24 consecutive dry days were observed in the state. The volume of storage structure based on water availability and demand obtained was 5 m 3 per household. It is felt that the volume can take care the domestic water demand.