| Intro |
As the demand for water resources continues to grow, the current “demand management” approach oftenfails to deliver the expected results in terms of reduced water consumption, release of water to otheruses, or improved environmental conditions. Recognizing that evapotranspiration (ET) represents thedominant consumptive use of water in the hydrologic cycle, this paper describes an approach to basin-scale water resources management based on ET. The ET management approach comprises four stages:(i) a basin-scale water consumption balance; (ii) determination of a target ET consistent with sustain-able water consumption; (iii) identification of water consumption tradeoffs, competition and feedbackamong different water sectors (agricultural, industrial, domestic, and socio-environmental); and (iv)basin-wide monitoring of sustainable water consumption. Continuous, basin-wide ET data obtained fromthe ETWatch models are combined with estimates of water consumption as a result of mechanical, chem-ical, and biological energy to assess the water consumption balance, and set targets. On this basis, waterresource managers can identify opportunities to achieve sustainable, productive use of water resourcesby (i) reducing non-beneficial ET; (ii) converting non-beneficial ET to beneficial ET; and (iii) increasingthe productivity of beneficial ET. Irrigated agriculture is usually the largest controllable contribution toET in a basin, so meeting the target ET for agriculture is key. A water balance analysis for Hai Basinand the implementation of ET management in the Basin are presented to illustrate the ET managementapproach. |
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