Résumé
This paper studies groundwater management in the presence of rainwater harvesting (RWH). We propose a two-state model that takes into account the standard dynamics of the aquifer and the dynamics of the storage capacity and we assume that the collection of rainwater reduces the natural recharge. We analyze the trade-o¤ between these two water harvesting techniques in an optimal control model. In particular, we show that when these techniques are pure substitutes, the development of RWH leads in the long run to a depletion of the water table even if pumping is reduced.