Introduction

Rapid urban development and industrial growth puts direct and indirect pressure on freshwater resources in many water-scarce basins. Direct pressure derives from domestic and industrial demands, while indirect pressure relates to an increasing urban food demand. In fully allocated basins, both demands can often only be met by reallocation of water (for example, from irrigated agriculture, which is in most cases the largest water user), and through conscious efforts to reuse urban return flows (Falkenmark and Molden, 2008). Using waste water volumes (which are continuously increasing) can have negative environmental and health effects in cases where a large share of the waste water is returned untreated to surface water bodies; however, this problem can be addressed and the water remains a significant resource that cannot be overlooked. Such water has a natural place along the rural–urban gradient in integrated water resources management (IWRM). When scope for increasing water supply has become exhausted, another response to water demand pressure is water conservation – increasing water use efficiency or introducing water reuse at source.

The speed and extent of any adaptation to water pressure varies between countries and their understanding of IWRM, and depends on the strength of various drivers such as the country's political economy, the technology available, and shock events (Molle, 2003). Taking India as an example, the World Bank expects that demand for water for industrial uses and energy production will grow at an annual rate of 4.2% up to 2025 (World Bank, 1998), even though the projected population growth rate will decline from 1.4% to 0.9% between 2006 and 2025 (GoI, 2006).