Follow Us:

Freshwater plunge~I

Healthy lakes not only provide a number of environmental benefits but also influence the quality of life and strengthen our economy.

Statesman News Service |

The Earth is a closed system, meaning that very little matter, including water, ever leaves or enters the atmosphere. Its water is finite, meaning that the amount of water in, on and above the planet does not increase or decrease. Water that was here billions of years ago is still here now. In photographs taken from space, one can see that 71 per cent of our planet’s surface is covered with water. Hence, the Earth is called the ‘Blue Planet’. The abundance of water is distributed in different forms ~ Ocean water: 97.2 per cent; Glaciers and other ice: 2.0 per cent; Ground water: 0.62 per cent; freshwater lakes: 0.009 per cent; Inland seas/salt lakes: 0.008 per cent; Soil moisture: 0.005 per cent; Atmosphere: 0.001 per cent, and rivers: 0.0001 percent. Intransigent, obdurate, intractable, perverse ~ these and similar words are commonly used and are often suitable descriptions of freshwater in today’s world.

Indeed, though the earth has an abundance of water, roughly 97 per cent is saltwater and less than 3 per cent is freshwater. Most of Earth’s freshwater, around 79 per cent, is frozen in glaciers and ice caps; and around 20 per cent is in deep underground aquifers. Less than one per cent of the Earth’s freshwater is easily accessible to us or meeting our needs and most of that water is replenished by precipitation ~ vital component of the water cycle, affecting every living thing on Earth. Put another way, if all the water on Earth had the same volume as an egg, only eight drops would be available for human consumption. If a faucet leaks at the rate of one drop per second, it loses ten thousand litres in a year. These two facts aptly underline the scarcity as well as the precious nature of this resource necessary for life on the planet.

Three things happen to the water that falls from the clouds: it evaporates, percolates or stands in the form of water bodies such as lakes, which provide water in our immediate vicinity. Lakes are indispensable for agriculture as well as industry, for rural areas as well as urban centres. Lakes are relatively large water bodies of slow moving or standing water that occupy an inland basin of appreciable size. These are important lentic freshwater ecosystems, where the water quality is governed by many environmental and seasonal attributes. They not only support aquatic life, but also cater to our socio-economic needs. They provide opportunities for recreation, tourism, fishing and for our drinking. They also help replenish ground water and have an impact of flood and droughts. Healthy lakes not only provide a number of environmental benefits but also influence the quality of life and strengthen our economy. But profit motivation has lowered our ecological sense.

India’s huge and growing population is putting a severe strain on all the country’s natural resources. Disparity in water coverage exists across the country. Increased anthropogenic activities have led to a nutrient build-up in the lakes, especially phosphorous and nitrogen, leading to algal blooms and eutrophic conditions. Algal bloom produces hepatotoxins and neurotoxins that are of ecological and public health concern. A report entitled ‘Composite Water Management Index (CWMI)’, published by NITI Aayog in June 2018, mentioned that India was undergoing the worst water crisis in its history; that nearly 600 million people were facing high to extreme water stress, and about 2 lakh people were dying every year due to inadequate access to safe water. The report added that India was placed at the 120th rank amongst 122 countries in the water quality index, with nearly 70 per cent of water being contaminated.

Indeed, the situation in India is dire. In the 75 years since Independence, annual per capita availability of water has declined by 75 per cent- from 6,042 cubic meters in 1947 to 1,486 cubic meters in 2021. Not only are we staring at depletion of groundwater and pollution of surface water, but also vanishing water bodes ~ ponds, lakes, tanks and wetlands ~ thanks to encroachment. The way out is to make communities care for these waterbodies. Hence, it is the responsibility of all citizens to protect, preserve and benefit from the valuable freshwater resources. The global water cycle in which evaporation from the oceans falls as precipitation on the land and flows back to the oceans through streams that become rivers is being radically intensified and accelerated by global warming. The warmer oceans allow significantly more water vapour to evaporate into the sky. Scientists have measured an extra 4 per cent of water vapour in the atmosphere above the oceans, and even though 4 per cent does not sound like much, it has a large effect on the hydrological cycle.

Because storms often reach up to 2,000 kilometres, they gather water vapour from large areas of the sky and funnel it inward into the regions where storm conditions trigger a downpour. By analogy, if we pull the drain in a bathtub filled with water, the water rushing down the drain does not come just from the part of the tub directly over the drain, it comes from the whole tub. In the same way, the great basins of water vapour in the sky are funnelled to the ‘drains’ opened above the land by rainstorms and snowstorms. When these basins are filled with much more water vapour than in the past, the downpours are more intense. Bigger downpours lead to bigger floods. They rush across the land, eroding the soil. And less of the water seeps down through the soil to recharge the underground aquifers. On 10 February 2020, the Union Minister of State for Jal Shakti & Social Justice and Empowerment in his written reply informed the Rajya Sabha that India receives annual precipitation of about 3880 billion Cubic Metre (BCM).

After accounting for evaporation and evapo-transpiration etc. the average annual water availability in the country has been assessed as 1999.20 BCM as natural run-off. It has been estimated that owing to topographic, hydrological and other constraints, the utilizable water is 1122 BCM which comprises of around 690 BCM of surface water and 432 BCM of total annual groundwater (GW) recharge. The country has an estimated live storage capacity of 257.812 BCM. Mahatma Gandhi aptly said: ‘Owing to our neglect and folly, the years’ rains are allowed to run down into the Bay of Bengal and the Arabian Sea.’