Rainfall and other forms of Precipitation

It has been dominated by reports of  a major cyclone Thane that lay centered on the the 29th December 2011 near latitude 12.30N and longitude 83.00E, about 300 km east-southeast of Chennai (Tamilnadu) and 480 km north-northeast of Trincomalee (Sri Lanka). Earlier reports related to the cyclone Thane indicate predictions and cyclone warnings made by the IMD for the north of Tamil Nadu and the south Andhra Pradesh coast along with possibility of heavy rains and severe winds and warnings for fishermen to refrain from going into the sea.

Later reports indicate that Cyclone Thane has hit the landfall between the Union territory of Puducherry and neighbouring Cuddalore district in Tamil Nadu at about 9 am leaving behind a trail of devastation followed by later reports of weakening of the cyclone activity and predictions of heavy rainfall over Kerala, south interior Karnataka and north interior Tamil Nadu

The most affected will be Tamil Nadu followed by Puducherry, Andhra Pradesh and Kerala leading to floods, overflowing of dams and damage to property. Assessments of the earthquake in Sikkim are now ready as information is finally available.

Guest post by : Aarti Kelkar-Khambete

The news this fortnight has been dominated by the north-east monsoon in South India, mainly in Tamil Nadu and Kerala. Periyar, Vagai, Krishnarajasagar, Mettur and Chemberampakkam reservoirs have either reached full capacity or are expected to in the next few days. Areas downstream of Vagai reservoir received flood warnings.

In the cities of Tamil Nadu, heavy rains and inadequate infrastructure have led to damage to life and property, with 10 people dead in two separate incidents. 

Winter precipitation has begun in Kashmir, with the higher reaches receiving snowfall. 

Adequate potable water supply to the community has become an uphill task to the administration both in rural and urban areas. This is because of dwindling groundwater sources, over-extraction, pollution of surface water bodies, negligence of fresh water bodies, poor water management, etc.

The monsoon has become active in the states of Tamil Nadu, Kerala, Lakshadweep and parts of coastal Andhra Pradesh. There are also reports of heavy rainfall in parts of Karnataka. At the same time, news from the north in the states of Himachal Pradesh and Kashmir includes reports of a cold wave and rains and the first snowfall of the season.

Northeast monsoon

This report by the Kerala State Council for Science, Technology and Environment (KSCSTE) and Centre for Water Resources Development and Management (CWRDM) on water quality monitoring in Kerala covers all its forty four river basins. This is being done under the “Environmental Monitoring Programme on Water Quality” under which samples are being collected both from surface and groundwater sources.

Groundwater sampling stations were fixed after conducting a sanitary survey in the panchayats. Water Quality Information System is being developed using Geographical Information Systems (GIS) to manage the water quality from point or non-point source of pollution.

In the first phase of the project, three river basins of Kerala viz. Kabbini, Periyar and Neyyar were monitored. The network was later expanded to basins such as Chaliyar, Kadalundi, Meenachil, Karamana, Anjarakandi, Pamba, Muvattupuzha, Bharatapuzha, and Chalakudy. 

This paper published in the journal Current Science presents the findings of a study has been taken up to quantify the possible impacts of the climate change on the water resources of Indian river systems within the constraints of the uncertainty of climate change predictions. The study uses the PRECIS daily weather data to determine the spatio-temporal water availability in the river systems.

A distributed hydrological model, namely SWAT has been used to simulate all the river basins of the country. The analysis has been performed to evaluate the severity of droughts and floods and thus identify the vulnerable hotspots that may require attention in view of the climate change in various parts of the country.

Impacts of climate change and climate variability on the water resources are likely to affect irrigated agriculture, installed power capacity, environmental flows in the dry season and higher flows during the wet season, thereby causing severe droughts and floods in urban and rural areas. Climate change impacts on water resources which are addressed and analysed in the present study include impacts on annual and inter-annual water availability as well as extreme events of droughts and floods.