Principles of water management for people and the environment.
This book chapter identifies and discusses 10 basic principles of water resource management that take into account population dynamics and environmental protection. The earth has 1.4 billion cu. km of water, but only 41,000 cu. km circulate in the hydrological cycle. Human population reached 5.3 billion in 1995 and is expected to reach 7.9-9.1 billion by 2025. Human demands for water for domestic, industrial, and agricultural use have risen rapidly. 10 principles of water management and the environment pertain to valuing water, using water sustainably, developing suitable institutions to manage water, collecting and disseminating information, maintaining a social and cultural perspective, ensuring equitable access to water, using appropriate technology, trying to solve causes not symptoms, taking an ecosystem approach, and working as a multidisciplinary team. Water should be allocated to uses that result in a net gain for society and that are measured by economic benefits minus costs. Barbieri et al. (1997) find that the economic value of water for intensive irrigation is much less than its value for supporting fisheries, agriculture, and fuelwood in wetlands downstream. Efficiency criteria do not account for who wins and loses in a particular management scheme. Water valuation may rely on inadequate information on ecological and hydrological processes. Economic valuation may compete with ecological concerns; thus it is just one input into water management. Water sustainability is enhanced by drip irrigation, water charges, reuse of waste water, desalinization of seawater, and waste treatment at the source.