Currently, importance of water has increase many fold due to the constant pressure it faces as a result of the increasing population and all the other related activities it brings along. On top of it, the changing climate may also alter the distribution and quality of water resources, which will definitely affect the livelihood of the people. Further, extreme conditions of floods and droughts are a common feature, which affect the availability of water for various purposes.
The impacts of climate change on water resources have been highlighted in the Fifth assessment report of the Intergovernmental Panel on Climate Change (IPCC) indicating an intensification of the global hydrological cycle affecting both the ground water and surface water supply. Climate change is likely to have an adverse affect on the water balance in different parts of the state due to changes in precipitation and evapo-transpiration. Increased rainfall intensity during the rainy season may lead to high level of runoff and the available topography of the state would possibly reduced the ground water recharge.
WATER RESOURCES IN THE STATE
The National Wetland Atlas 2010, developed by Space Application Centre has identified 167 wetlands (≥ 2.25 Ha) and 541 wetlands (<2.25 Ha) covering 63,616 ha i.e. 2.85% of total geographic area under different types of wetlands like lake / pond (61.5%), river/steam (26.2%), waterlogged (5.5%), aquaculture pond (4.2%) and others (2.58).
It also reported that Manipur has 15 major rivers / streams having 166.77 sq. km. of total area i.e. about 0.75 % of the total geographical area of the state. About 90% of the drinking water supply in urban area of the state is from the three major rivers namely Imphal River, Nambul River and Iril River. There are four major river basins of Manipur state -
· the Manipur River Basin in central Manipur,
· the Yu River Basin in the east, and
· a portion of the Liyai River Basin in the north.
The wetland of the state is mostly confined to three valley districts of Bishnupur (30.7 % of total district of total district geographic area under wetland), Thoubal (30.3% of total district geographical area) and Imphal West (2.6 % of total geographical area under wetland).
Groundwater in the state is mostly exploited through open wells. As per reported by the Central Ground Water Board (CGWB), ground water in the deeper aquifers occurs under sub-artesian and artesian conditions. Tube wells have also been installed at various places of the valley areas. Considering the clayey nature of formation in the top aquifer, development of this resource is not considered promising on a large scale.
WATER SUPPLY SYSTEM IN MANIPUR
Manipur, though falls under high intensity of rainfall area also faces acute shortage of water particularly during dry / lean season i.e. January - May every year. All the riverine system of the state originates from the hills and their flow depend on the annual monsoon. Deforestation in the hill area of the state also leads to heavy siltation and disturb the water flow of the rivers. The problem is further aggravated due to the climate variability, as a result, the state is also facing erratic monsoon for the past few years resulting to shortage of water supply every year.
Every year, the state is facing acute drought like situation, particularly during the months of February to May, mainly due to depletion of raw water at source and drying up of all the water bodies like Ponds, Lakes, Moats, etc. More over, about 2 % of the domestic water supply in urban area is being supplemented by the private transporting tankers. At present water storage & distribution system in both the urban & rural areas of the state are reported.
RAINFALL IN MANIPUR
Manipur receives heavy rainfall from the South West (SW) and North East (NE) monsoons, the average annual rainfall readings were 1116 mm in 1972 and 2646 mm in 1983 and 2887.6 mm in 1995. However, overall average total rainfall during the last 6 decades (1961-2010) was 1435 mm. Most of the districts of Manipur experienced a decrease in precipitation in the last few years. In 2014, the annual average rainfall of Manipur was recorded as 750.21 mm, which is way to low to be called a high intensity rainfall area. The distribution of the annual rainfall widely varies with Imphal West recording just 164.94 mm while Tamenglong recorded the highest at 2160.6 mm.
The lost of water due to evaporation in Manipur for 2014 was recorded at 196.03 mm. The highest evaporation rate was recorded at Imphal West with 325.5 mm and the lowest in Chandel with 16.2 mm.
Water use efficiency should be increased by optimizing the water use with the help of different state government’s agencies like PHED, IFCD, Forests & Environment etc. to continue availability of water for various purposes. Strategy is framed on water resources under state action plan on climate change to ensure integrated water resource management including conservation & protection for improvement of water resources, minimize wastage and more equitable distribution both across & within states.