The project will be implemented in the area of the Nida River valley on a section with a length of approx. 39 km between Brzeźno and Pińczów. Its main objective is to pave and restore the continuity of the ecological corridor of supra-regional importance, including the Nida River Valley. The objective of the project will be achieved through the implementation of investment activities consisting in the elimination of existing migration barriers and artificial restrictions for aquatic organisms. These actions will include, first of all, the clearing of 8 barriers on the Nida River and 4 on the Mierzawa River. The project also provides for other activities ensuring the possibility of migration of living organisms, consisting in restoring and increasing the valley retention of the Nida section covered by the project, including as a result of the liquidation of existing embankments, the activation of ageing forests and the use of natural floodplains located in the Nida valley. Achieving the objectives of the project will be achieved by performing 6 tasks: 1. Increase in surface and submersible retention in Umianowice. 2. Restoring the patency of the ecological corridor of the Nida River and its tributaries - clearing migration barriers for aquatic organisms on the Nida and Brzeźnica rivers. 3. Restoring the patency of the ecological corridor of the Mierzawa River - clearing migration barriers for aquatic organisms on the Mierzawa River. 4. Revitalization of the Nida river in Brzeźno. 5. Revitalization of the Pińczów Lagoon and the Nida River Old Orchard in the area of the Pińczów city treatment plant. 6. Restoration of the inland delta of the Nida River. As part of the Project, it is planned to carry out demolition works related to the removal of weirs and floor thresholds, demolition of existing sections of embankments, shaft and road culverts, elements of drainage trench networks together with equipment. Within the scope of the project, it is also planned to carry out construction and assembly works related to the construction of overpasses, construction of new sections of embankments and culverts, construction and reconstruction of access roads to buildings, expansion of shaft ramps, reconstruction of old-growth and drainage ditches, installation of flaps on shaft culverts and installation of measuring devices. The section of the Nida River covered by the project was anthropogenicly modified by performing a series of drainage treatments in the 20th century. As a result of drainage and drainage, the natural river valley was destroyed, which had soil and surface retention capabilities. The drainage activities carried out, including the hydrotechnical construction, led to the crossing of natural ecological corridors and limiting the possibility of free migration of aquatic organisms. There was also an acceleration of the run-off and the flow of the Nida river bed below the regulated section. This resulted in an increase in the frequency of flooding phenomena and an increase in the extent of flooding, and thus an increase in the level of flood risk in areas inhabited and developed in the Nida river valley. The implementation of the activities provided for in the Project, related to the increase of valley retention, will contribute, in addition to the typically environmental benefits, also to the restoration and improvement of the hydrological regime as a result of increasing the water catchment retention capacity. As a result, the additional benefit of the project will be to reduce the level of flood risk for inhabited areas located in the Nida River Valley.