EN
The results of the investigations concerning the needs and possibilities of water conditions renaturization on hydrogenic areas in the Middle Biebrza Basin were discussed. This Basin represents the wetlands which are located within the Biebrza National Park the part of them were transformed as a result of drainage. Because of the large area of the Middle Biebrza Basin and its different conditions, the investigations concerning renaturalization were concentrated on the selected part of the Basin within the triangle area bounded by the Jegrznia River, the Ełk River and the Woźnawiejski Canal. Basing on the results obtained from these investigations for this part of the basin the mathematical models were worked out. The interactively working models are capable to simulate water cycle in the hydrographical network as well as soil moisture conditions in the unsaturated zone of soil profile. The developed optimisation-simulation model allows the selection of the possible solutions from the point of view of the performance of different renaturization activities. The necessity of water conditions changes on selected pilot area by increase discharge capacity of the old beds of the Jegrznia and Ełk rivers and reduction of flows in the Woźnawiejski Canal was shown. Some activities related to implementation of this objectives were undertaken. Primary observations results of such activities shows that planed aim i.e. increase of the soil moisture conditions on the drained area can be achieved.