The Effects of Agricultural Water Pricing Policies on the Sustainability of the Water Resources: A Case of Irrigation Network in Qazvin Plain

摘要

Qazvin plain in Iran is one of the most fertile regions for crop production, but it has been suffering from severe crises in water resources, inefficient water allocation, and improper cropping pattern due to low tariffs in recent years. One influential policy in the context of sustainable water resource management is suitable pricing. Given the legal potentials and technical conditions for the adoption of various pricing policies, the present paper addresses the effect of area, volumetric or two-part tariff pricing policies with the scenarios of pricing by water supply cost, economic value, or residual value of water on economic variables and water use rate. To this end, positive mathematical programming method was adopted and the data were collected through a questionnaire from the farmers served by the irrigation network of Qazvin plain. Also, experts' opinions were collected and a library study was conducted. The results show that area pricing policy has no impact on water use management in crops irrigated with sprinkler or flood systems and increased water use by as high as 72% in alfalfa farms irrigated by flood system. Volumetric policy and two-part tariff policy reduces water use by as high as 45% in most cropping systems with various irrigation technologies and encourages farmers to use sprinkler or tape irrigation technologies. However, given the negative economic impacts of these pricing policies on local farming, it is imperative to offset their adverse impacts by alternative policies that can improve water resource sustainability and at the same time, do not cause fluctuations in economic interests of users.