ASSESSING URBAN WATER-USE AND THE ROLE OF WATER CONSERVATION MEASURESUNDER CLIMATE UNCERTAINTY

There has been substantial analysis of the possible impact of climate change on water supply, especially with respect to runoff and river fl ows. Less attention has been given to urban water use. Little is known of the suitability of various water use forecasting models for predic ting climate impacts or of the best procedures for assessing this issu e. This paper will: (1) demonstrate the feasibility of a scenario appr oach to describing possible changes in climate, (2) evaluate the IWR-M AIN model as a source of plausible water use forecasts given uncertain future climate, (3) test the effectiveness of conservation and pricin g interventions in reversing the postulated effects of climate change, and (4) assess the significance of climate change for future urban wa ter management. Other possible responses to climate change, such as su pply augmentation, are not explicitly considered. Using data for the W ashington (DC) metropolitan area, the study reveals problems with IWR- MAIN version 5.1 when used for this purpose, but results in a reasonab le assessment of the possible water use consequences of climate change . Variation in future water use due to climate uncertainty was found t o be moderate compared to other uncertain influences, and well within reach of feasible policy interventions.