Freshwater – Introduction
Since the last century, we have misused water sources so much that we are inching towards a situation where there will not be much left to do our basic chores.
We are yet to find a substitute for water. There is just so much water to go around, and we keep leaving a large water footprint. We depend upon freshwater for almost all of our uses.
Earth has 2.5% freshwater in it. Most of this freshwater is in the form of ice sheets (glaciers) or are rooted in the ground. The only freshwater is usable.
Water with less than 1% salt content is freshwater. Freshwater also does not have dissolved solids. Freshwater includes mineral-rich water of chalybeate springs. All pool is freshwater except for seawater and brackish water.
Freshwater is found in lakes, ponds, bogs, aquifers, springs, etc. Much of the freshwater is locked in glaciers and ice sheets.
Freshwater is not portable ( drinking ) water. Most of the water cannot be used as drinking water without some kind of treatment.
Apart from drinking, fresh water is used in agriculture, industries, and dairies. Agriculture utilizes the bulk of freshwater followed by industries, especially by meat industries, dairies and domestic consumption.
Source of freshwater
Ponds and lakes:
ponds and lakes are scattered throughout the earth’s surface. The pond may be large or small, having an area of a few square meters to thousands of square meters. Many lakes are seasonal, which dry up during the dry and hot season. They are filled with water only during monsoon season (especially lakes existing in the regions experiencing monsoon type of climate).
Ponds support limited species diversity as they are often isolated from one another and other water sources like rivers or streams. Lakes are more significant than a pond. Many lakes are remnants of Pleistocene glaciation. Lakes existed for hundreds of years. Lakes have limited diversity for not being connected to rivers and seas.
Rivers and streams:
These are masses of moving water flowing in one direction. They get their start either from snowmelt, springs, or even lakes. They travel to their mouth through the middle course. These rivers and streams drain either in the sea or in other water bodies.
Rivers, in their upper course, have a high oxygen level, water is more transparent, and more freshwater fishes, trouts, and heterotrophs are found. By the time the river reaches the middle stage, it widens and has more species diversity.
Freshwater in the river at this point is not good because of pollutants being added to it regularly. By the time it reaches the lower stage, it gets murkier with sediment. Oxygen level too is less, so very few species are found at this part of the river.
Wetland includes marshes, bogs, ponds, swamps. These are formed on flat land around rivers or streams, the water level is high, and runoff is slow. Water fluctuates due to seasonal flooding. Plants like lotus, cypress water lilies are common. Plants growing in wetlands are called hydrophytes.
Freshwater is also found in aquifers.
It is a body of rock and sediment which holds groundwater. There are two types of aquifers-
a) confined aquifer:
when groundwater is over a layer of solid foundation or clay, water is limited to a place where its free movement is restricted to some extent.
When these are penetrated well, the water rises because the water in a confined aquifer is under pressure, which is more than that of atmospheric pressure. These confined aquifers are called artesian wells.
b) Unconfined aquifers
Here, water seeps from the ground directly above the aquifer. Unconfined aquifers are found below watercourses. Water from these sources flows down to form aquifers.
Importance of freshwater
Civilizations have developed around freshwater systems. All the major rivers of the world have seen the extensive development of civilizations.
Nile and Tigress rivers were the epicenter of Mesopotamian Civilization, Indus and Ganga rivers had Indus valley civilization, Yellow River had its civilization in China.
Today too, the concentration of population and development is more on places around the river.
Freshwater is vital for life. It supports the ecosystem and human civilization.
Uses of water are integral to our daily life. Freshwater supports our food production, power generation, sanitation, manufacturing even recreation.
The first and foremost importance of freshwater is providing us with drinking water. Clean drinking water is essential for our well being.
Since freshwater is the primary source of drinking water, the cleaner it is lesser we need to treat it to convert it to portable water.
Freshwater has also become a source of clean generation of power. Thermal power plants cause pollution, so there is an urgent need to shift to a more legitimate source of power generation. Dams and reservoirs built across rivers provide an opportunity to generate power.
Freshwater and sanitation are essential for human development and prevention of the spread of diseases.
Many manufacturing units need freshwater to manufacture. Agriculture uses freshwater to produce. Freshwater bodies provide food and employment to millions of people.
People living around lakes, ponds, and wetlands have essential connections with the water bodies through experience, practices, and history. They have a sense of belonging and identity. Maoris in New Zealand have their lives revolve around lakes they have lived since eons.
Freshwater on the land surface is an integral part of our life. Earth’s surface water is considered renewable resources, but they depend on other parts of the water cycle.
The water cycle begins with the evaporation of surface waters by the sun. It is carried to higher altitude by air current where it cools because of low temperature and condenses to liquid again. These water droplets are held in clouds.
When it becomes too heavy to carry, it falls back to earth as rain or snow. Most of it falls in oceans and some directly in freshwater. Some of the rain flows to freshwater as runoff, some seeps into the ground and collects as groundwater.
The amount of water in lakes and rivers keep changing because of changes in inflows and outflows. Factors affecting inflows are precipitation, overland runoff, groundwater seepage, and tributary inflows. Flow from these water bodies includes evaporation, movement of water into groundwater withdrawals by people.
Over the centuries, the act of people have been reckless and indiscriminate, and abusive use of fresh water has resulted in renewable resource turning into a scarce resource.
Freshwater sources support a broad range of plants and animals ecosystem. This ecosystem is determined by the level of oxygen present, sunlight it receives, availability of food, and temperature. The freshwater ecosystem is an essential center of biodiversity.
In a dry environment like an oasis in deserts, freshwater provides a haven for plant animals and humans alike. The freshwater ecosystem has been subject to relentless attacks of pollution due to human activities, deforestation, and urban development.
Freshwater is a vital resource for humanity. Its overuse and misuse over the centuries have rendered it polluted and unfit for any form of life.
We need to put our act straight and take every step to prevent pollution and depletion. If we do not act immediately, then we are staring at water crises in the immediate future.
Pollution in freshwater and depletion of freshwater
We have overused and misused our freshwater resources to the point that scarcity has alarmingly set upon us.
Freshwater available to us for use is finite, with only 1% if it was usable. Pollutants like chemicals microorganism present in the water render it unsuitable for human consumption and harmful to the environment.
Water is easily contaminated because of it being a universal solvent. Toxic substances from farms, factories, and towns pollute freshwater bodies. It affects not only human life causing health hazards, but it also affects animals and plants dependant on it.
Global warming, pollution coupled with over-used freshwater, many lakes, rivers, and other water bodies have dried up, leading to the disruption of a healthy life.
Freshwater is essential to the survival of the human race. Therefore, we need to protect it and use it judiciously so that other species dependant on it can use its water.