Since Botswana is part of drought prone region of Southern Africa due to its semi-arid climate, conservation and careful management of the water resources is a matter of necessity and great importance. Hence, the focus on water resources management and, in particular, integrated management has become critical over the past decade. This paper addresses the problem of water resources development with a particular reference to Botswana, which is a semi-desert region. The vagaries of climate, unpredictable, patchy rainfall, and even more erratic run-off events all make hydrological modeling difficult. High rates of evaporation and evapotranspiration losses present an additional challenge to water resources planners. Lack of good dam sites is another problem in Botswana's ancient, flat, and eroded landscape. This paper describes the present and future water demands of this country and a suggestion is made to improve the situation of water shortage. The Botswana National Master Plan has been developed to meet the challenge. The aim is to integrate the expanding water supply system of eastern Botswana, through a north-south carrier pipeline. A brief presentation and discussion of this system is given along with other challenges faced by the water resources planners, such as conjunctive use of the groundwater and surface water resources.