Irrigation water demand for the decision maker

Abstract

This paper deals with the problems of estimating irrigation water demand. We propose an original method of estimation in two steps. First, we develop a dynamic programming model in order to explain the optimal irrigation management plan. Based on a microeconomic approach describing the farmer's behavior, this economic model, introducing an agronomic model, and an algorithm of solution search, is used to compute a realistic database. Second, these data are used to estimate profit functions by a non-parametric method. The irrigation water demand function is estimated using a non-parametric derivation procedure.An application to irrigation water demand is proposed in the southwestern area of France where conflicts appear frequently. The same results appear for different climates: for small quantities of water available, irrigation water demand seems to be quite inelastic. If one increases the total quantity of water available, the shape of the curve changes and the demand appears more elastic. The threshold price at which the changes in price-responsiveness appears, depends on weather conditions and range from 0.30 F/m 3 in a wet year to 1.60 F/m 3 in a dry year. These results are crucial information for the regulator in order to analyze the effects of a water regulation policy, based on prices. The impact of an increase in the water price will depend not only on the climate but also on the location of the initial and final prices on the demand function.

Quels instruments pour gérer les prélèvements individuels en eau souterraine ?

“…Bien que la demande en eau soit générale-ment considérée comme peu élastique à court terme (Bontemps et Couture, 2002), une hausse de la redevance prélèvement des Agences de l'eau est susceptible, dans certains contextes, de conduire les agriculteurs à modifier leurs pratiques d'irrigation (réduction des apports et baisse des rendements objectifs), à remplacer les cultures irriguées par des cultures pluviales ou à choisir des cultures moins consommatrices en eau. À plus long terme, cette hausse peut inciter les exploitants à investir dans des équipements d'irrigation plus performants pour améliorer l'efficience technique (comme le goutte à goutte).…”

Price elasticity reconsidered: Panel estimation of an agricultural water demand function

“…As mentioned above, previous papers have generally used programming models [Bontemps and Couture, 2002;Hooker and Alexander, 1998;Schaible, 1997]. Econometric estimates by Kanazawa [1992] use a much greater level of aggregation.…”

“…[4] Many previous studies of agricultural water demand rely on simulated data and linear programming techniques [Bontemps and Couture, 2002;Hooker and Alexander, 1998]. In general, these studies consider an individual's response to changes in the price of water under varying conditions.…”

Impact of Water Reallocation on the Economy in the Fertile Crescent

“…Since the 1910s, most policy-makers and researchers have considered the scarcity of water and its effects on both developing and developed countries as a global threat (Bontemps and Couture 2002). Water shortages restrict economic development, impact urban industries and may affect the environment (United Nations 2003).…”