Optimal Conjunctive Use of Surface and Groundwater with Recharge and Return Flows: Dynamic and Spatial Patterns

Abstract

scarcity and the environmental impact of water use is a topic of growing concern. Improving efficiency in irrigation water allocation, in terms of both scarcity and environmental impact, has drawn considerable attention from many economists and planners. Traditional studies usually model water allocation assuming that the users are independent. However, many early water resource economists pointed out the interdependency in water users (Hartman and Seastone; Johnson, Gisser, and Werner; and O'mara). Considering the external impacts of water use on other farms, equating the marginal product of consumptive use is not necessarily an optimal outcome.Water rights and transfers are widely recommended instruments used to promote efficiency of allocation (see, for example, Easter, Rosegrant, and Dinar). But since water transactions may result in water being transferred/transformed over space, time, and form, administrative review processes have been deemed a necessary oversight mechanism. These procedures, however, represent substantial transaction costs and tend to inhibit actual water transfers and robust water markets (Howe). This calls for a system for determining efficiency prices over space, time, and form. By announcing exchange rates based on efficiency prices, the governing authority can streamline the review processes and expand trading.This article derives the efficiency price patterns for a comprehensive spatial and dynamic model of conjunctive water use that incorporates externalities

On the Environmental Efficiency of Water Storage: the Case of a Conjunctive use of Ground and Rainwater

“…Azaiez [2] develops a multi-stage model to determine how much surface water must be imported for irrigation and to arti…cially recharge the aquifer, which is also and simultaneously used for irrigation. Pongkijvorasin and Roumasset [26] develop an optimal control model where groundwater users enjoy positive externalities from canal conveyance loss and from return ‡ows to the aquifer from irrigation. But, these studies still consider surface and groundwater as two separate entities, only related by the fact that some surface water is lost to deep percolation or is used for aquifer recharge, representing positive externalities on the aquifer.…”

Rainwater Harvesting and Groundwater Conservation: When Endogenous Heterogeneity Matters

“…One strand of the literature deals with optimal management of multiple groundwater resources (see Wada 2012 or Zeitouni andDinar 1997). Another strand studies the conjunctive use of ground and surface water (see Burt 1964;Chakravorty and Umetsu 2003;Gemma and Tsur 2007;Knapp and Olson 1995;Krulce et al 1997;Pongkijvorasin and Roumasset 2007;Stahn and Tomini 2009, 2011or Tsur and Graham-Tomasi 1991. Roumasset and Wada (2012) showed that optimal management of several independent groundwater resources depend on their marginal opportunity cost: only the resource with the lowest marginal opportunity cost is used initially, whereas in the steady state, all resources are used.…”