In the Nilgiris District of Southern India, a majority of the rural population does not have access to an adequate supply of water for domestic use. With the groundwater resources showing signs of depletion, the Government of Tamil Nadu has made it mandatory to install rooftop rainwater harvesting (RWH) units on all households within the state. Figure 1 illustrates a typical small-scale rainwater harvesting system. Unfortunately, most rural villages in the region have limited ability to financially support this initiative. Since the largest cost component of the rainwater harvesting structure is the storage unit, careful planning must go into sizing RWH units to ensure the people receive an adequate supply of water, at the lowest possible price.
Dan Olsen, an intern with Engineers Without Borders, created this case study based on his experience in India and while completing his master’s degree at McMaster University.
This case study is intended to illustrate the design process and the effective use of simple models, using Excel, in the solution of engineering design problems. The social context of engineering is also highlighted.