ABSTRACT. – Man-made storage-lakes – between necessity and environmental change. The ancient practice of building storage-lakes registered an explosive development in the 20th century. Originally used as drinking water sources, these lakes have aquired complex utilisations today: hydroenergetic, drinking, irrigation, fish-rearing, flood attenuation and agreement. But their primary purpose remains the supply of energy and of drinking and irrigation water. However, the construction of pretty large reservoirs (in terms of volume and area) has also produced many changes in the geographical landscape. The present paper discusses the differences between man-made and natural storage-lakes, altered the environmental geographical system that have been suffering alterations and gives a regionalisation outline of the Romanian territory connected with the opportunity of further building these types of lake.