Forecast assessment of water regime efficiency and changes in water consumption on drained lands of Western Polissia of Ukraine in a changing climate

The article presents forecast data on the impact of changing weather and climatic conditions on evaporation and water demand on the drained lands of Western Polissia of Ukraine in different periods of their development. These data are the basis for the development of appropriate adaptive measures aimed at reducing the negative impact of changing weather and climate conditions on drained lands and increasing the efficiency of their use. Computer simulation modeling of various climatic scenarios was planned to accomplish the objective. The forecast was made through a machining experiment based on the implementation of a corresponding complex of forecast-simulation models regarding the main regime-technological variable parameters of drainage systems, local climatic conditions, water regime, water management technologies, and productivity of drained lands for schematized natural, agrotechnical, and meliorative conditions. Vegetation values of total evaporation and water demand formation of drained lands were determined for the long-term forecast module of water supply regarding variable climatic and agro-meliorative conditions. The technological efficiency of different irrigation technologies (subsoil irrigation, sprinkler irrigation) of drained lands was evaluated. The research showed that in the Western Polissia of Ukraine, the water supply module for irrigating drained lands varies significantly depending on the type of crops, drained soil (mineral, peat), irrigation technologies, and heat and moisture supply conditions during the vegetation period. It has been experimentally determined that under current climatic conditions, the value of the water supply module is 2.9 times higher than the existing recommended design values, and under the predicted conditions of their change, this excess is 5.2 times. At the same time, the water demand of cultivated crops increases almost 2–3 times and determines the need to increase water consumption for moistening drained lands in conditions of sufficient water shortage. It has been established that the main content of the necessary adaptive measures is to increase the moisture availability of soils with regulated water regime by switching from periodic to regular moistening of them through the use of appropriate resource-saving technologies for regulating the water regime.