396
which have fairly thick vegetation of mixed crops
and plantations, (b) the valley fi lls of laterite alluvium
and colluvial deposits with low-level areas which
are intensely cultivated and thickly populated and
(c) the fl oodplains and alluvial plains of the Kallada
River on the south which are mostly cultivated.
Hydrology
The wetland does not have any visible feeding
inlet. However, the springs at the bottom of the
wetland are supposed to supply water to the wetland throughout the year. The average annual
rainfall is 2,398 mm, while the mean annual temperature varies from 26.7 to 29.16 °C. Groundwater
table is said to be at depth of 3.89 m.
Water Quality
The wetland water is said to be free from common
salt or other minerals and metals. The quality of
surface water, interstitial water and sediments is
briefl y stated below.
Physico-chemical Features of Water
and Soil (Average Values)
(a) Surface water : pH 7.25; conductivity 63.00
millimhos/cm; PO 4 , phosphorus 4.93 μg/l;
Plate 20.71 Sasthamkotta wetland
20 Wetlands of India