Sasthamkotta Lake is designated as Ramsar Wetland on August 19, 2012. This wetland is the largest freshwater lake in Kerala, a state on the south of the West Coast of India.
History of the Place
The lake is named after the ancient Sastha temple. Sastha Temple is a pilgrimage Center located in Kerala.
Sasthamkotta is a historical place where the Second World Religion Conference had been carried out, in which the Global Religious Celebrities had particularly participated.
Access to the Wetland
The locals call it as ‘Queen of Lakes,’ mainly because of the refreshing beauty that surrounds the place and cultural extravaganza in the form of temples.
Sasthamkotta Lake is situated at a distance of 25 kilometers from Quilon city, which is on the northern side of Ashtamudi Lake for tourists to visit.
Thiruvananthapuram International Airport, at 105 kilometers, is the closest airport to Kollam. Karunagapally, at a distance of 8 km, is the nearest town to the lake.
There is also a ferry service across the lake that transports people between West Kallada and Sasthamkotta.
Topography of Area
A large amount of the lake land was occupied for agriculture. Presently, the surface area of the lake is around 373 hectares. Most of the lake area was surrounded by mountains. Its average depth is 6.53 m (21.4 ft) with a maximum of 15.2 m (50 ft).
Geology of Area
The place is located at a 9.03°N 76.63°E range of latitude and longitude. The rock formations that can be found at Sasthamkotta Lake are as follows: archaean, charnockite, biotite gneiss, and dolerite. In the lake, portions of sand and silt deposits are also documented. Geomorphological divisions of the lake’s basin area comprise of:
- the undulating uplands have relatively thick vegetation of mixed crops and plantations
- the valley fills with laterite alluvium and colluvial deposits willow-level areas that are intensely cultivated and thickly populated
- the flood plains of the Kallada River on the south are mostly nurtured
Hydrology of the Land
There are no tributaries for Sasthamkotta lake to feed water. The main source of water for this lake comes from its bottom. The volume of water in the lake is measured to be of the order of 22.4 million cum.The average annual rainfall in the area is 2398 mm. The annual temperature of Sasthamkotta lake varies between 26.7 °C and 29.16 °C. The groundwater level in the area is recorded at a depth of 3.89 meters.
The plants that grow on the bank of the river are plantation crops. They are cashew, plantain, and tapioca. Drosera, generally known as the sundews, is primarily seen on the lake’s eastern shore.
Common fish species recorded here are Calichrous bimaculatus and Wallago Attu. Some of the vulnerable and endangered species are:
- Puntius ticto punctatus
- Horabagrus brachysoma
- Parambassis Thomas
Around 27 species of freshwater fishes, pearl spot and catfish, two genera of prawns, 21 species of herrings, and sardines of the family Clupeidae can be found here. Usually, a large number of monkeys are also spotted there.
Islands in the Lake
There are several smaller water bodies and waterlogged areas in the south and southwestern parts of the Sasthamkotta lake. Monroe Island is a cluster of eight tiny islands and is surrounded by the Kallada River, Ashtamudi Lake, and Sasthamkotta Lake.
The island is named after Colonel Munroe, who was the British Resident of the erstwhile state of Travancore. It is adorned with several criss-cross canals and zigzag water channels. A backwater cruise along the waterways will fetch the unblemished beauty of village sides full of coconut lagoons.
Economic Evaluation of the Lake’s Resources
This lake fulfills the drinking water needs of half a million people of the Quilon district. The purity of the lake water for drinking use is associated with the existence of a large population of larva called cavaborus that expends bacteria in the lake water. On top of that, this place also provides fishing resources. Some 27 freshwater fish species are also present in the lake, which benefits the fishermen. Tourism plays a vital role in the economic contribution of the lake.
Deterioration of the Lake Environment
The environment of the Sasthamkotta Lake is affected by the following factors:
- The people dispose of domestic and agrochemical wastes from surrounding areas into the lake.
- Soil erosion of the banks from the encroached land.
- Effluents from domestic sewage.
- Increasing anthropogenic pressure.
- Encroachment on parts of the lake for agriculture.
- Cultivating tapioca has increased soil erosion and runoff into the lake basin.
- Decrease of groundwater recharge to the lake due to increase in agriculture in the area around the lake.
- Soaking of dry leaves of coconut palm before matting is used for thatching huts.
The problems of lake protection started with the declining agricultural activities in the Kallada village. There are 400 acres of agricultural land in the village, and as per the local people and the local agricultural office, 820 paddy fields have been converted for clay mining.
Hence, the Kerala State Government formulated a Conservation and Management Action Plan in 1999 for the lake’s sustainable utilization and conservation and to address the threats faced by the lake. Financial support for this implementation has been taken from the Central Government under the National Lake Conservation Plan.
The Management Action Plan envisions the following activities:
- Agro-forestry in the catchment
- Pollution abatement
- Weed control
- Preservation of flora and fauna
- Fishery development
- Awareness campaigns among the residents
The activities are followed and planned by the Kerala Water Authority (KWA), Department of Forests and Wild Life, Department of Fisheries, State Fisheries Resource Management Society (FIRMA), and District Rural Development Agency (DRDA).