In river basins throughout the world, rivers connect and pass through urban and rural districts; and groundwater aquifers, which underlie urban and rural areas, are connected to the rivers. Sources of pollution occur in both urban and rural areas: point sources, such as sewer outfalls and industrial discharges, are the main sources in urban areas; while nonpoint sources are generally worse in rural areas, including runoff from agricultural lands and discharges from intensive animal husbandry. Regardless of sources, pollution adversely affects urban and rural residents, contaminating groundwater and degrading water quality of rivers and lakes that are the sources of urban and rural water supply. The river health of most rivers in developing countries is deplorable, and past efforts to address the problems have been inadequate and piecemeal. Because the sources of water and the sources of water pollution extend through urban and rural parts of river basins with visible and invisible linkages, a new approach that simultaneously tackles the problems in both urban and rural areas promises to be more effective.
This new approach, the urban–rural water linkages (URWLs) approach, also relates to land use, which alters runoff and infiltration, in turn modifying characteristics of floods and droughts. Land use change can trigger accelerated rates of soil erosion; leach nutrients that degrade water quality; and cause river sedimentation that modifies the morphology of rivers and streams, which alters flood risk. Integrated water resources management (IWRM) has long been a central principle in this regard, requiring a holistic, river basin-scale approach to water resources and environmental management with spatial and functional integration of management measures, including structural and nonstructural measures. The URWLs approach advocated in this report complements IWRM by focusing on the need for integration of interventions in urban and rural parts of river basins to secure benefits sought (i) to improve the welfare and livelihoods of urban and rural communities; (ii) to maximize prosperity and equity; and (iii) to conserve natural resources, like rivers, upon which prosperity depends while enabling their sustainable exploitation. A URWLs approach recognizes the interdependency of urban and rural society, and identifies the important linkages between quantity and quality of water resources and their management in urban and rural areas.
