COMPUTATIONAL STUDY OF WATER LOSS FROM UNLINED CANALS TAKING INTO ACCOUNT THE GEOLOGICAL AND SOIL FEATURES OF THE NORTH OF KALMYKIA

Abstract

Purpose: carrying out filtration calculations of the main canals (MC) and comparison (comparative analysis) of the obtained values. Materials and methods. The object of study is the water supply network of the Sarpinsky irrigation and watering system (SOOS) in the North of Kalmykia. The initial data for the study were the field survey data of the system canals, as well as materials for official use obtained in the operating organization. When performing filtration calculations, the physical and geographical features of the irrigation network location area were taken into account and the method for calculating backed filtration from a canal (in an earth channel) was used under conditions of a steady movement of the seepage discharge. The calculation was based on the application of the filtration resistance method. Results and discussion. Taking into account the features of the geological and soil conditions of the northern regions of Kalmykia, the calculated values of filtration losses from the MC system were determined, which amounted to 2.7–6.51 l/(day sq. m) for the calculated sections of the MC VR-1 and 5.46 l/(day sq. m) – for MС R-1. Comparison of the data obtained for the MC SOOS with the results of studies of unlined sections of the Great Stavropol Canal, laid in the similar geological conditions, confirmed the authors' assumption that the values of seepage flow rates from the MC were significantly affected by the presence of clay soils at the canal bottom. Conclusions. As a result of the research, it was found that the value of filtration losses from MC SOOS is significantly affected by the geological and soil features of the system location area, and in particular the low permeability of mantle loams, as well as the presence of impervious Khvalyn clays of marine origin. The studies of other authors have confirmed that the close occurrence of these clays to the day surface contributes to flooding and land salinization, this was not taken into account when developing irrigation in the north of the region.

Keywords

• irrigation systems
• irrigation
• groundwater
• backed seepage
• filtration coefficient
• main canal
• earth channel
• groundwater regime
• khvalyn clays