The modeling tool is applied to address water management issues in the case study region (Sharm El Sheikh, South-Sinai, Egypt) that suffers from water shortage and that is located near a unique but sensitive marine environment of high ecological value. The main economic activity in the city is tourism.The modeling tool box is composed of five types of models depending on the specific site situations: water demand/need model, water supply model, wastewater reuse model, environmental model and economic model. The coupling of the models facilitates assessing different scenarios for integrated water resources management including different time-variant domestic and irrigation water demand, water supply options: long-distance piping and reverse osmosis desalination (RO), potable and non-potable water supply contracts between a hotel and a water company, optimum capacity and expansion for an RO desalination plants, renewable and non-renewable energy sources for RO desalination, and brine disposal options.