摘要：Following recent policy changes by the United States Bureau of Reclamation (USBR) irrigationdistricts in the Central Valley Project of California (CVP) are now required to adopt volumetricpricing for irrigation water as a Best Management Practice (USBR, 1998). This requirement isalso being promoted in other western regions and is the most recent in a series of USBR policiesaimed at reducing agricultural water consumption in the arid west. Adoption of conservationpricing by irrigation districts has, however, been limited in both scope and effectiveness. Arecent survey by Michelsen et al. (1999) found that most irrigation districts charge for waterbased on acreage served rather than water delivered, and that those districts which do haveconservation pricing policies set water rates sufficiently low as to have no impact on demand. It is not clear if conservation pricing actually reduces water consumption. Recenttheoretical results by Huffaker et al. (1998) raise serious questions about the value of price as aconservation tool and suggest that more empirical analysis is needed. In particular, Huffaker etal. demonstrate how a combination of return flows and price-induced changes in irrigationefficiency can overcome the demand effects of a change in water price.
