The analysis of the current state of weather and climatic conditions and evaluation of their predicted changes for immediate and distant prospect in the drained areas of Ukrainian Polissia region was carried out in the article. The main trends in changes of meteorological characteristics and their possible effect on the conditions of functioning water management and ameliorative objects and complexes as well as on the natural and ameliorative state of drained areas were identified. The research uses a method of predictive-simulation modelling with used predictive assessment models of normalized distribution of the basic meteorological characteristics in the long-term and one-year vegetation context. According to the results of the research it was established that, for today a high variability in meteorological characteristics can lead to the significant deterioration of operation conditions of water management and ameliorative objects and units, as well as natural and ameliorative conditions of drained lands in Polissia region as a whole. Core measures regarding the adaptive potential enhancement and development in the region under the conditions of climate change were examined.

Drainage on drained lands is the main regulator of water-air and general natural reclamation regime. Currently, the most promising economic and mathematical method is considered, which combines the advantages of hydro-mechanical and empirical methods and is based on the implementation of a set of forecast and optimization calculations. However, in the conditions of transition to market relations, this method, as it is implemented, does not allow to determine the optimal drainage parameters differentially with respect to different levels of crop yield in compliance with modern economic and environmental requirements in the changeable natural-agro-reclamation conditions of the real object, so it needs further improvement. In this regard, the principles of construction and implementation of a comprehensive model for optimizing agricultural drainage parameters are developed, taking into account the climatological strategy of object management, based on the implementation of interrelated structural and technological, forecast-simulation and optimization blocks of models. This makes it possible to determine economically feasible and environmentally acceptable design solutions based on the relevant criteria. As economic criteria and conditions of the optimization deal with the minimization of costs subject to climatic risk, and environmental component -condition in the form of a matching constraint values of the module of drainage flow within the system ecologically acceptable value. The scientific principles of construction and implementation of structural-technological, forecast-simulation and optimization blocks of models based on changeable natural-agro-meliorative conditions of a real object have been developed, which allow obtaining differentiated values of yield corresponding to the considered variants of drainage parameters, as well as evaluating the technological and environmental efficiency of its operation within the project period.