Around 96.5 per cent of all the earth's water is stored in oceans. The water in the oceans is saline in nature and hence is not drinkable. The remaining 3% are freshwater, with less salt, but they are mostly trapped in the vast glaciers and ice sheets of Greenland. Lakes, rivers, soils, and the atmosphere partly hold fractions of freshwater.
Freshwater reservoirs on land replenished by the hydrological cycle are extremely important for people, animals, and plants. These water bodies provide water not only to animals and people but also replenish groundwater and encourage vegetation.
Rain falling on the earth is retained as soil moisture, essential for the earth's vegetation. Rainwater percolates through soil layers and pores to reach the underground water bed, which are freshwater aquifers. This forms the groundwater, which is a source of drinking water for us.
Water plays an important role in the life functioning of the Plant. Plants draw water from the soil through their roots, which contain essential nutrients for the plant’s growth. Water pressure (turgidity) helps maintain the cell structure of plants. Plants need water to make their foods through photosynthesis.
Plants exchange water for maintaining temperature. The water absorbed through roots flows through the plants due to osmotic pressure circulating nutrients, and removing waste. The leaf stomata open up to release the water back into the environment.
Drying up the soil leading to water scarcity, can disrupt this essential process. Extreme temperatures cause heat stroke in plants. The common effect of water stress in plants is wilting of leaves. The plant appears to limp and begins to collapse as the plant cell loses the turgor pressure.
Lack of water hampers photosynthesis and can even completely halt the process. The leaves become yellow at this point.
Water stress can affect plant respiration, by which plants break down nutrients to generate energy. Lack of water reduces photosynthesis which in turn affects respiration.
Water Scarcity in plants can eventually kill them by influencing all the above processes. Few desert plants have evolved to survive in dry areas. They have penetrating roots to search deep under the ground for water. Their leaves are modified to reduce water loss by adopting a thorn-like structure.
The causes of water scarcity are mainly human actions along with some environmental factors. Some common reasons for water scarcity are:
Human activities have deeply harmed the water ecosystem of the earth, as large human habitats are reporting water crises. Population increase has pressurised the already scarce water resources. Dense urban habitat overconsumes the groundwater in the region for drinking purposes.
Concretisation of cities prevents rainwater from percolating through the soil and replenishing the groundwater reservoir. Most of the rainwater runs off and gets polluted. Industrial effluents and sewage also pollute the water bodies rendering them unusable, which then goes on to degrade the vegetation around them.
Increases in global temperature have shifted the weather pattern. High-temperature results in greater evaporation of water from the oceans leading to abnormal rainfall. Sometimes there is sudden heavy rain followed by long dry spells leading to drought.
Degrading or destroying the natural freshwater reservoir like ponds, lakes, and wetlands due to urbanisation adds to the water woes. They are natural water retainers and purifiers. These reservoirs are a lifeline for the local vegetation.
Overuse of groundwater due to irrigation can run the underground water bed dry, resulting in desertification and subsequent water scarcity.
The condition of water resources has deteriorated due to environmental degradation, human irresponsibility, and climate change. Water scarcity is also a result of poor social planning and underdevelopment. The mitigation effort has to address these problems. We should adopt practices to manage the water available to us better.
Few ways to improve water scarcity-
Better wastewater management facilities should be built to reuse the wastewater from households for other purposes, such as gardening.
Sewage and industrial effluents should be treated before releasing them into rivers or lakes to protect the surrounding vegetation.
Natural water bodies need to be preserved and maintained across our landscape. We should avoid dumping waste into these water bodies and provide proper legal and social protection to these reservoirs to save them from encroachment and construction.
30% of land in India has undergone desertification due to the depletion of wetlands, deforestation, and over-cultivation.
Hygrometer and soil moisture sensors are used to measure the volumetric water content in the cell.
71% of the earth’s surface is covered by water.
Only a small fraction, about 3%, is freshwater which is essential for plants, animals, and humans.
Generally, water scarcity is caused due to depletion of natural sources, which leads to the degradation of vegetation.
Plants need water to maintain basic life functions.
Water scarcity disrupts the basic processes in plants and causes heat shock.
1. What are the types of water scarcity?
Water scarcity can be physical or economical-
Physical scarcity is due to the absence of water. Climatic conditions such as intense heat or drought can cause a severe water shortage. Lack of infrastructure to store water or deterioration of natural reservoirs can cause physical loss of water.
Economic water scarcity is simply the lack of money to build adequate facilities which can use the water from available sources to meet the demand. It points to poor investment in infrastructure and capacity building for proper drinking water distribution.
2. How does soil retain moisture for plants?
Adding organic compost helps soil retain water, and covering the soil surface with leaves, shredded paper, and bark prevents drying up of the soil. Less frequently, but deep watering helps plants grow better.
3. What are the signs of water scarcity?
Trees usually begin to shed leaves, and bare dead branches are exposed upon facing water stress. The leaves wilt or become yellow. In the area hit by severe water shortage, the soil begins to lose the green cover, and the bare soil becomes hard and develops cracks.