Hydrological regime of Molochnyi Liman under anthropogenic and natural drivers as a basis for management decision-making

Molochnyi Liman is the largest liman (22,000 ha) at the northern coast of the Sea of Azov. Contrary to estuaries, it is an ecotone without typical tides. It is a half-closed water body, with a connection to the Sea of Azov that has periodically renewed or ceased over the course of time. Molochnyi Liman is a wetland of international importance, a hydrological reserve of state significance and is part of the Pryazovskyi National Natural Park. The results of our research have established that termination of the liman/sea connection has led to significant hydrological changes. The most crucial is a reduction in the liman's depth, accompanied with shrinkage in the water surface area, a dramatic increase in salinity to 95 g/l and the loss of several Ramsar criteria. Restoration of the Molochnyi Liman ecosystem requires a positive water balance. There is a need for ensuring the inflow of at least 100 mln m3 of marine water into the liman through a connecting channel. This will renew normal functioning of the liman and reduce the salinity to an optimal level. The methodical approach used in this work can also be applied to other closed and half-closed water bodies of the Azov-Black Sea Region. The development of a hydrological model can be effectively used as a supportive tool for the management of the Tylihulskyi, Khadzhibeiskyi and Kuyalnytskyi limans in the north-western part of the Black Sea.