This is a large dam in the Coonoor taluk, used for supplying drinking water to Coonoor town. The reservoir and wetland are situated in the upper area with a forest of Acacia, Eucalyptus and some sholas as catchments. The wetland is vast. There is a large water body and then a dry, swampy region. On one side are small wetlands next to the large water body. Some of them as small as a few meters, yet performing the functions of the wetland. Here we found an abundance of insectivorous plants. The insectivorous plants are mostly found in highly nutrient deficit wetlands. The wetland becomes nutrient deficit when the recharge of water does not take place. In a wetland like Raliah adjoining the reservoir recharge is unlikely to happen and so the high density of insectivorous plants.
An interesting feature in the area was the presence of a peat bog. It was small in size, marshy with red scum coating on the soil as well as on the water. It smelled heavily of methane and gaseous emitions. It is surrounded by wattle. Near to this peat swamp was a stream which finally joined the main reservoir.
Biological and Botanical Narrative
The wetland is the source of water to the reservoir. The wetland was dominated by Eriocaulon spp. and Juncus spp. (which was dry).The soil was dry on the surface and wet underground. Viola and Centella were found in moist places near the edges. Gentiana quardifaria and an insectivorous plant, Drosera burmanni was found abundant on the black moist soil.
The wetland was surrounded by Wattle and Pine plantation and small patch of shola forest on one side. Sighting of birds like Barn owl, Pond Heron, Egret and Common grass yellow butterfly was seen.
Frogs, water spiders, dragon fly, bees (Apis cerana) were seen near the water course. Signs of cow dung, scat of, Panther, Beer showed the presence of grazing and wildlife in the area. Malabar giant squirrel was sighted in the shola
Numeric Criteria – Water quality
The following table gives the water quality for various parameters.
|Permissible limits||Observed value|
|Residual Chloride (mg/l)||0.2||0.2