Water and Salt Balances of Katlabukh Lake Under Different Conditions of Water Reservoir Operation

Abstract

Katlabukh Lake is a part of the Danube Lakes system and is one of the surface water sources for water supply, for agricultural needs and irrigation of the region. Changing the conditions of operation and regulation of the reservoir led to a decrease of water levels and an increase of salinity, which makes it impossible to use water for different management needs. Calculations of the water and salt regimes of the lake based on the solution of the equation of balance said that in the water balance of Katlabukh Lake the main volume of the revenue part for the period 1980-2018 was precipitation (36.1%) and water inflow from the Danube River (38%), and the expenditure part – evaporation together with transpiration (50.5%). Salt flow into the lake is mainly due to surface inflow (53.4%) and water of the Danube River (25.5%), and loss of irrigation (45.1%) and water discharges to the Danube River (31.9%). Simulation modeling of the water-salt regime of the Katlabukh lake under different conditions of exploitation of the reservoir showed that corrective management measures are needed to improve the qualitative indicators of the water in the reservoir. They consist in the fact that for three summer months it is necessary to carry out forced pumping of poorly mineralized water from the Danube River to compensate for evaporation from the water surface (on average in volumes of the order of 55 million m3) or to carry out fences of water from the lake for irrigation in 60 million m3. This will allow to reach the design values of water mineralization in the lake equal to 1.0-1.5 g/dm3. Thus, addressing a range of problems to conserve and restore the rational use of the natural resources of Katlabukh Lake requires effective managerial water management activities that require additional feasibility studies.

Hydrochemical regime and water quality of the Danubian lake Katlabukh

“…The hydrochemical regime and water quality of lake Katlabukh are influenced by several factors: the volume of runoff of small rivers and its mineralization; the volume of water intake for irrigation and water supply; the amount of precipitation and evaporation from the water surface of lakes; the volume of filling from the Danube and discharge of water into the river (Romanova et al, 2019). Determination of water mineralization was carried out according to the laboratory of the Danube BDWR in such facilities as Lake Katlabukh, Velykyi Katlabukh, Yenika, and Tashbunar.…”

“…The Danube lakes existed mainly due to the hydrology of the Danube. At the same time, their geographical location along the banks of the Danube had little effect on their historically established hydrochemical regime (Gopchenko et al, 2011;Romanova et al, 2019). With the intensification of agriculture in the 1970s, the additional use of the floodplains of the Danube began, and to protect them, embankment dams were built along the Danube, which radically changed the hydrological and historical water regime of the Danube lakes.…”