Urban water, an essential part of Integrated Water Resources Management
ABSTRACT: The necessity of managing water in an integral way is currently not argued. It is considered unavoidable. This comes forth from the scarcity and intense concurrence for good quality fresh water in many areas of the world and the important political and social stresses this generates inside a country and between different territories. Integrated management is linked to the concept of considering the river basin as a unit for management, or exceptionally the aquifer system. Human beings cannot change this physical reality except by performing major works to link distinctive basins, but even in these cases physical boundaries do exist. Due to the relatively small fraction of water resources humans use directly to attend their needs, a preliminary analysis of water resources quantity problems – water quality is a different point of view – tend to ignore urban water as an essential part of a water resources planning when compared to the much larger water volumes required to produce food, fibers, and energy, and to sustain important ecological services, especially in semi-arid countries. However, the situation is very different when an analysis is made taking into account the real value of water for human supply and the different urban cycles the water passes through in a river basin or linked river basins. This is due to the strategic importance of adequate water supply for the human being to attain desirable standards of health, sanitation, life, and economic activity, as well as due to the important impacts and conditioning that urban cycles impose on the river basin. From a quantity point of view, water scarcity is mostly linked to agricultural demand since in general water supply can easily meet the water demand for direct human in a wide territorial context, although quality problems may become a limiting factor in areas that have limited financial resources. Important urban problems may be solved through making adjustments in the agricultural water use domain. Only an integrated analysis of all the involved factors, giving the due weight to urban water, may minimize problems and provide reasonable solutions to current stresses. This integrated analysis has to consider both quantity and quality aspects, and also the involved energy, ecological and territorial implications. Although the discussion has a general scope, comments are largely based on the experience in Spain.