Engineering-geological and geomorphological conditions of Kaspiysk in connection with flooding

Abstract

Relevance. Determining the geomorphological and hydrogeological conditions of the area of the city of Kaspiysk, including the Karabudakhkent district, in connection with the development of the city and the processes of flooding of the territory is of great importance. At present, the city of Kaspiysk, as well as the city of Makhachkala, is intensively expanding in all directions. The study area belongs to the Primorskaya Plain with negative and positive relief marks. Due to the high level of groundwater (GWL), more than a critical value, their high aggressiveness is noted, as well as soils lying above the GWL, the seismoacoustic properties of soils also change. Aim. Determine the zones of drained (Z-D), poorly drained (Z-SD) and very poorly drained (Z-VSD) territories, determine stagnant areas and hydrogeological regions depending on the ratio of the filtration properties of the upper and lower (if any) soil strata. Methods. Collection of accumulated material on engineering surveys. Compilation of tables of groundwater chemistry. Determination and interpretation of the filtration properties of the upper water-bearing soil strata, including up to the regional aquiclude. Determination of the slope of the day surface on characteristic sections with a general depression towards the sea. Results. Given the chemical composition of groundwater for 15 objects. The hydrogeological conditions of the city area are shown according to engineering and geological surveys, for 35 objects, including the depth of groundwater, the type of soil in terms of seismicity, the depth of the regional aquiclude, the types of three hydrogeological regions, and the slopes of the terrain. The drainage zones of the territory and the boundaries between them are determined. Thus, the area of the buried lagoon with groundwater mineralization from 21 g/liter (near Lake Ak-Gel) to 89 g/liter (MKR-9) is shown. For the hydrogeological region GR-1, a horizontal type of drainage is recommended, for GR-2 – vertical or combined types of drainage, for GR-3 – underground drainage is not effective. The need for seismic microzoning of the city of Kaspiysk with the prospect of further development was indicated. The need for seismic microzoning of not only the studied area, but the entire city of Makhachkala, with the prospect of further development, was indicated.