Missing Markets and Redundant Reservoirs

This paper uses a two-sector, two-period,spatial model of groundwater usage withstochastic surface water supply to illustratethe potential for the suboptimal management ofthe timing of groundwater uses. A ``timeprofile externality'' is said to exist when thetiming of groundwater extraction by one set ofusers impacts on the time profile of wateravailability to another set of users. Theexistence of the time of use externalitydepends on the presence of importantdifferences in the preferences between thecontrol and non-control sectors. It alsodepends on the absence of the markets thatwould internalise these differences. Oneimportant implication of the existence of suchexternalities is that they can inducesub-optimal insurance investments in the formof water storage capital, i.e., unnecessarysurface water reservoirs.