This paper discusses the possible effects of various ways of charging for water in an integrated modeling framework adapted to the Drâa River Basin in southeastern Morocco. Declining surface water availability in the basin has led to an increase in groundwater use for irrigation in recent decades, even though groundwater extraction is more costly than using surface water. The trade-off between the pricing of ground and surface water is discussed based on recursive-dynamic simulations over a ten-year period. The results identify groundwater pricing as an economically and environmentally favorable option, assuming that revenues from water charges are redistributed to farmers.