Consequently, to the construction and operation at water power plant Gabcíkovo came to changes in water regime in adjacent area. The power canal of the Gabcíkovo power plant cut the upper parts of the drainage system in Danube Lowlands. Groundwater level changes have occurred in the vicinity of the Hrušov reservoir what caused changes in discharge and water level regime of the drainage channels. Presented contribution deals with theoretical and practical background of the water management in agriculturally exploited regions, especially with the possibility to create and store enough water for irrigation in the channels of one part of the Rye Island. It was therefore necessary to measure and calculate the capacity of given channels as well as the volume of water stored by means of improved operation on hydraulic structures or by construction of new structures. Rye Island belongs to an area where agriculture in the growing season, especially due to the irregular distribution of precipitation, very often suffers from drought. The probability of ensuring at least 10 mm of precipitation in one decade of the growing season is only 50% and the probability of 30 mm of precipitation is only 20%. It follows that without irrigation the moisture for vegetation cover is not ensured. But there can be years with heavy rainfall and then there is no need to irrigate. Rye Island is the warmest area of the Slovakia where the vegetation period is also the longest. Most of it belongs to the area of corn production type. The irrigation economy is therefore profitable. However, the technology of implementation and the effort to introduce large-scale irrigation as soon as possible led to the conclusion that this issue should be considered from several points of view.