Do Solar Powered Irrigation Systems (SPIS) Contribute to the Overexploitation of Groundwater Reserves

Introduction

The common argument against the utilisation of SPIS is that this technology goes hand in hand with overexploitation and eventually depletion of limited water resources such as groundwater. Concerns are based on the following reasoning: SPIS lead to free pumping and hence an overexploitation of groundwater reserves is inevitable or at least very likely.

From a resource economist perspective, this argument is known as the Herder Problem or “the Tragedy of the Commons”  first described by Hardin in 1968: If there is a finite common-pool resource (e.g. groundwater) where it is difficult and costly to exclude potential users, this resource will eventually be exhausted because the rational individual will maximise his/her own utility rather than conserving the resource for the benefit of all. Meaning that an open-access resource will inevitably be over-exploited unless access and use of this resource are restricted by some form of governmental regulation or the allocation of property rights .

As an effect of the over-exploitation of a groundwater resource not only the environment but also the economy and society within the affected region have to suffer from several effects:

• Unsecure water availability through drying wells and springs increase the risk of crop failure;
• Aquifer salinization and seawater intrusion with long-term implications for agricultural productivity;
• Increased risk of conflicts between different users (e.g. farmers, domestic water supplier, industrial users);
• Environmental impacts on groundwater-dependent ecosystems, such as drying up of wetlands and river base flows