These lakes were formed by the process of water filtration from
the Canal. Depressions in sand dunes were filled with water and
desert vegetation was flooded. Water logging began and desert
soil transformed to the meadow type. In connection with that de-
sert vegetation was replaced by hydrophilows plants. The belt of
filtration lakes reaches 2 km on the right bank, on the left bank
it is comparativery low (200 m). Some of these lakes evaporate in
connection with the flactuation of water table in the Canal, so
the process of soil salinization occured.
IY. The state of desert environment after the 20 years
period of the Canal construction. Nowadays sand dunes are stabi-
lized by vegetation and new sand relief is formed. The belf of
filtration lakes become wider.
One time and especilly repeated aerial photography allow
not only study gualitatative features but also to obtain guantita-
tive criterea. Fig I. gives an example of such analysis based on
repeated aerial photography covered the same area affected by the
Canal.
The area occupied by lakes and hydrophilous vegetation .
reached in I965 about I4 4 of the total area of the key plot. In
I976 this srea increased to 32 %. The area covered with water didn't
change during this period, it was egual 3,5 %. The comparative study
showed that the Canal was widened. On the key area per cent of area
covered with the Canal in I965 was 4,5 and in I976 it reached 7,5 %.
In the areas affected by the Karakum Canal we have also
studied by aerial photos the coefficient of the process efficiency
(table 2). The information of such type may be used to elaborate
measures on melioration of desert lands affected by the Karakum
Canal. These lands occupy vast areas (table 4).
Table 3.
Comparative criteria of the lake
formation process efficiency in the
areas affected by the Karakum Canal
Gee GH) GED Geen Ges GEE Gms GEN emo GENS Ges GEST NOW GNSS GEES m o o GES Sees mae GEE me
Years i Total num- | existed | New formed | Coefficient of the
1 ber of lakes ! lakes ! lakes i efficienby
I965 4I I6 25 0,6
1976 64 27 37 0,6
CD END aD WE ME U meee Gee ENS A "=" SD GE SESS Gems Ged qum» cnm Ge GES anum c m een cm
656
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I965