Project Summary

The second phase of the NATCOM (NATional COMmunication of India to UNFCCC) for climate change impact assessment on water resources of India was to improve upon the NATCOM Phase I study, in which again INRM was a partner, by using the revised projects of climate models and performing distributed hydrological modelling of the river basins of the country including the snowbound river systems.

The study was focussed at quantifying the impact of climate change on the water resources of the country. A distributed hydrological model (SWAT) has been used on all river basins using IPCC AR4 regional climate model outputs of daily weather data.

The study determines the present water availability in space and time without incorporating any man made changes like dams, diversions, etc. The same framework is then used to predict the impact of climate change on the water resources with the assumption that the land use shall not change over time. A total of 40 years of simulation over 14 river basins of the country have been conducted; 20 years belonging to control (present) and the remaining 20 years belonging to GHG (future) climate scenario.

Study Objective

Salient tasks of the study handled by INRM include:

• Hydrological modelling of all 14 major river basins of India.
• Climate change impact assessment on water resources availability.
• Vulnerability assessment for floods and droughts.
• GIS data preparation for web based GIS portal designed for dissemination of results to general users.

Findings

It has been observed that the impacts of climate change are not consistent over the country and vary across the river basins as well as sub-basins. The initial analyses have revealed that the GHG scenario may deteriorate the conditions in terms of severity of droughts and intensity of floods in various parts of the country. However, general reduction has been predicted in the quantity of the available runoff under the GHG scenario.

Figure: Annual average blue water flow availability per capita* for IPCC SRES A1B Basleline, mid century and end century scenarios

Of these wards, the vulnerability of 6 wards (14, 57, 58, 66, 67, and 108) in the eastern part and ward 80 can probably be explained by the inadequate infrastructure, unplanned land-use, and poor socio-economic and environmental conditions. The infrastructural problems are getting even worse in recent times with increased building activity as these areas have become attractive to developers after becoming part of KMC.

Linkage to the SDGs

Goal 6: Clean water and sanitation
Ensure availability and sustainable management of water and sanitation for all.

The study was the pioneer to provide the nation-wide information on the climate change implications to the water resources of the country and while doing so it provided a useful assessment of the present water resource availability for all the river basins of the country. This information is very important for sustainable management of the present water resources.

Goal 13: Climate action
Take urgent action to combat climate change and its impacts.

The assessment has provided a very detailed information on potential impacts of climate change water quantity, magnitude and frequency of floods and droughts, sediment erosion, as well as impacts on agriculture.