Том 51, № 6 (2024)

The diversity of natural conditions of the Crimean Peninsula determines different regimes of the main meteorological characteristics that determine the water availability for the territory. The estimation of the spatiotemporal heterogeneity of these characteristics and the solution of the problem of gaps in the ground-based observation data can be based on the results of calculations by general circulation models of the Earth’s atmosphere with assimilation of ground-based observation data, also known as atmospheric reanalysis. Estimates of the quality of reproduction of the surface air temperature and the total precipitation by atmospheric reanalysis models EWEMBI, ERA5-Land, and MSWEP are given and compared with data from ground-based meteorological observations. The main characteristics of the data sets used (both observational and calculated), the main verification methods, the results of estimates and the conclusions regarding the applicability of the data used in simulation problems are given. The mean errors of the models in air temperature and the amount of precipitation over various averaging periods (day, month, year) are given. Thus, the mean coefficients of correlation over different averaging periods vary within 0.74–0.97 for temperature and 0.52–0.79 for precipitation. The results show that all model reproduce the values of the temperature and total precipitation over different averaging periods with an acceptable accuracy; however, all of them show a tendency toward underestimation of the daily sums of precipitation along with an overestimation of the number of days with precipitation.

For experimental basins of karst aquifer systems of Mountainous Crimea, a three-component mixing model has been adapted using geochemical tracers. On its basis, the following stable sources of supply have been established: epikarst water formed mainly in the near-surface fractured and weathered zone of karst rocks; surface-slope water differing in the formation mechanism; base flow water of including a mixture of groundwater from the aeration zones of karst massifs below the epikarst and phreatic zones, providing the base part of the runoff hydrograph. Epikarst waters make up a significant share of the supply in the runoff of karst aquifer systems (> 30%). Close empirical relationships between the shares of the runoff components and the water discharges in the closing sections have been revealed.

An express method for determining water discharge based on calculating the surface flow velocity using the PIV method is considered. The method of performing measurements and the software operation algorithm for video images processing of a water stream are shown. The results of field studies performed using the developed method are presented, as well as the collation results obtained using standard techniques. The developed method makes it possible to obtain operational data on the water discharge data in a river or canal without expensive measuring instruments and specially trained personnel. Due to the determination of the flow velocity field along the entire transverse alignment of the studied water body, the method makes it possible to obtain more accurate water discharge data than standard measuring instruments (hydrometric turntables, float method), which are operated point-by-point at certain stations. The obtained data on water discharge can be used for scientific justification of work in the design of coastal protection, channel-regulating marine and river structures, as well as environmental assessment of the water body condition when studying the problem of water pollution. The use of this method at existing hydrological stations will make it possible to quickly determine the water discharge in rivers remotely using appropriate equipment, which is especially important in Crimea to assess peak runoff during the periods of high-water and floods.

A regional groundwater flow model of southwestern Crimea within the Alma artesian basin and the adjacent area of fissure-karst groundwater in Mountain Crimea was developed and calibrated for the modern period. On the basis of numerical experiments with this model, changes in groundwater resources under the influence of expected climatic changes in the 21st century were estimated. For this purpose, predictive maps of infiltration recharge were constructed for the selected study area. The predictive maps of groundwater recharge were developed for the plain part of the study area using infiltration water exchange modeling. For the mountainous part, precipitation accumulation by surface karst forms was considered in the prediction of recharge. The extreme climate change scenario SSP5-8.5 from the GSM models of the CMPI 5 family, which assumes maximum warming, was used as the prediction scenario. As a result of ensemble forecasting, the most contrasting scenarios of aridity index change were selected and three projected maps of groundwarer recharge change in the 21st century were obtained, which were then used in numerical experiments. The predicted infiltration recharge values significantly differ from the current figure of 366400 m³/day: under the «dry» climate, the recharge is 187900 m³/day, under the «average» climate, 283600 m³/day, and under the «wet» climate, 403300 m³/day. The results of the predictive groundwater balance modeling for the 21st century, using these recharge maps, demonstrated the high adaptive capacity of groundwater reserves and the reduction of minimum river runoff over the study period of about a hundred years, assuming the continuation of the current groundwater extraction rates.

The catastrophic situations of recent years – in June 2021 in the Yalta region and in January 2024 in Sevastopol – associated with heavy precipitation, rising water levels in rivers and the formation of mudflows, once again demonstrated the need for an early forecast of events with extreme precipitation in Crimea for a timely response and minimization of economic losses. The region of mountainous Crimea with its complex terrain and large slopes is especially susceptible to the emergence of dangerous situations after heavy (often multi-day) rains. Based on daily precipitation data from the Ai-Petri meteorological station, cases with a precipitation amount of ≥40 mm over three consecutive days were calculated and analyzed. Such conditions were used in the analysis as a threshold for extreme precipitation leading to erosion of river beds in mountainous Crimea and the formation of mudflows. The situation of a catastrophic flood on the river Chernaya in January 2024 is considered, caused by extreme precipitation that fell over three days in the Sevastopol region. Then, for such a situation, a study was conducted on the possibility of forecasting them with a lead time of 3 months using the developed artificial neural network model. The results showed satisfactory quality of the developed neural network for forecasting with a lead time of 3 months of 2–3-day extreme precipitation that intensifies erosion processes in the mountainous Crimea.

The main factors in the formation of the chemical composition of river waters of the northwestern slope of the Crimean Mountains have been studied, and the ecological state of river waters has been assessed. The data for the presented work were obtained as a result of summer field work in 2003–2022. The chemical composition of rivers is not constant and varies depending on meteorological conditions of a particular year and anthropogenic impact. The influence of geological and hydrogeological conditions on the composition of macro- and microcomponents in natural waters of the region is shown. Concentrations of chemical elements in surface waters of the Bodrak River basin can be used as natural (background) contents of chemical elements.

The aim of the article is analytical assessment of transformation of water management and reclamative complex of Crimea under water resource shortage. The study was conducted by using system, and information and analytical approaches with the use of methods of logical and comparative analysis, qualitative and quantitative analysis of statistical data. Dramatic change in the structure of fresh water withdrawal is revealed. The data on the growth of water losses as a result of increasing deterioration of water supply systems and small volumes of its rehabilitation is presented. The dynamics of reduction of specific water consumption for drinking and domestic purposes, insufficient supply of population with drinking water of high quality is shown. The influence of recycled water supply on saving in fresh water use for production purposes is considered. Dramatic decrease of the area of irrigated land, change in the structure of irrigated land use, rapid development of drip irrigation, and the role of irrigation in the production of the most important agricultural products are shown. It is revealed that the share of polluted wastewater is increasing, and the share of normatively treated water is decreasing. In the Republic of Crimea there is both a decrease and an increase in the discharge of certain pollutants. Water quality of most rivers of Crimea does not deteriorate.