Krasnodar GRES Project Volume I11 Environmental Assessment

4.2.2.2 Thickness and Occurrence of Aquifers
In the artesian basin, two hydrological floors are identified:
the upper one with free and impeded water exchange;
the lower with rather impeded water exchange.
Within the Mostovskoy region, the following aquifers and complexes of the utbper
geological floor are identified:
Water of alluvial-deluvial, eoliandeluvial, eluvial-deluvial and colluvial upper
quaternary recent formations (QIII - QVI) occurs sporadically. Water holding rocks
(loams, sandy loams, detritus) occur at a depth of 0.5 to 14.5 m (more frequently
from 2.0 to 5.0 m). The water level in river valleys and ravines is 0.2-3.0 m; on
slopes 5-12 m. The discharge of sources varies from 0.001 Ils, mineralization up
to 1 gll.
Since recent alluvium along the Laba river has no distinct boundaries with the
earlier quaternary alluvial deposits due to similar lithological composition, a single
alluvial aquifer (a QI-IV) is differentiated here. The filtration coefficient of gravel-
pebbly deposits is up to 60 mld, mineralization up to 1 gll. The average thickness
of this horizon is 15 m. These deposits are widely used for water supply.
No water-bearing complex of deposits of undivided Pliocene exists at the
construction site. .The gravel-pebbly deposits of the Pliocene terrace (Nz) can
possibly contain subsurface waters at a low depth from the surface. These are
fresh hydrocarbonate waters with mineralization of 0.6 gll.
The water-bearing complex of deposits with a typically middle Sarmatian fauna
and layers of the upper Sarmatian substage (Ns + Ns) occurs farther to the north
of the region under study.
Waters in the kryptomacro-layers of the middle Sarmatian substage (Ns) with
sporadic occurrence, are contained in sandy interlayers, under pressure, and are
usually slightly brackish. The filtration coefficient is 0.1 mid.
The water-bearing complex of the Trotonian ( N ) is linked to the interlayers of
limestones, sandstones, and sandy lenses in the Karangatian and Chokrackian
deposits. The thickness of the interlayers is up to 12-14 m. The water is
pressureless, drained by sources with a discharge from 0.01 to 2.8 Ilsec. It is
fresh (with mineralization 0.4-0.6 gll), the filtration coefficient of sands is 0.4-2.6
@ mld. and is used for water supply.
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