MODULE 1
SUBMODULE: WATER RESOURCES
Definition and Types of water resources
Water resources refer to the sources of water that are useful or potentially useful to humans and
ecosystems. They include:
1. Surface Water: Water from rivers, lakes, reservoirs, and streams. This is the most commonly used
source for drinking water, agriculture, and industrial processes.
2. Groundwater: Water located beneath the earth's surface in soil pore spaces and in the fractures of rock
formations. It is accessed through wells and is a crucial source for irrigation and drinking water,
especially in arid regions.
3. Desalinated Water: Water that has been treated to remove salts and minerals to make it suitable for
human consumption and irrigation. This is particularly important in regions with limited freshwater
resources, such as the Middle East.
4. Rainwater: Water collected from rainfall. It can be harvested and stored for various uses, including
drinking, irrigation, and recharging groundwater supplies.
5. Snow and Ice: Melting snow and ice from glaciers and ice caps can be significant sources of
freshwater, particularly in mountainous regions.
6. Recycled Water: Also known as reclaimed or reused water, this is wastewater that has been treated to
remove contaminants and can be used for non-drinking purposes, such as irrigation, industrial processes,
and replenishing groundwater.
Watershed Management
Watershed management is the process of creating and implementing strategies to manage the resources and activities
within a watershed to protect and improve water quality, enhance water availability, and support sustainable land
use. A watershed is an area of land where all the water that falls in it and drains off goes into a common outlet, such
as a river, lake, or ocean. Effective watershed management involves a holistic approach that considers the
interconnections between land, water, and living organisms.
Rainwater harvesting in India has gained significant importance as a sustainable water management practice,
especially given the country's varied climate and increasing water scarcity issues. It involves collecting and storing
rainwater for various uses, such as drinking, irrigation, and recharging groundwater. Here are key aspects of
rainwater harvesting in India:
Types of Rainwater Harvesting
Rooftop Rainwater Harvesting:
Collection: Rainwater is collected from rooftops and directed to storage tanks or recharge pits through a system of
gutters and pipes.
Storage: Water is stored in tanks made of plastic, concrete, or metal for later use.
Recharge: Excess water can be directed to recharge groundwater through soak pits, recharge wells, or percolation
pits.
Surface Runoff Harvesting:
Check Dams: Small dams are built across streams to slow down water flow and enhance percolation into the ground.
Percolation Ponds: Shallow ponds are created to capture runoff and allow it to percolate into the soil.
Recharge Trenches: Trenches filled with gravel and sand are used to capture and channel rainwater into the ground.
Benefits
Water Availability: Enhances water availability during dry seasons and droughts.
Groundwater Recharge: Helps in replenishing depleted groundwater levels.
Flood Mitigation: Reduces the risk of flooding by capturing and storing excess rainwater.
Water Quality Improvement: Reduces the reliance on contaminated surface water sources.
Cost-Effective: Lowers the cost of water supply in areas with limited access to piped water.
Implementation in India
Government Initiatives:
Jal Shakti Abhiyan: A government campaign focusing on water conservation and rainwater harvesting.
Atal Bhujal Yojana: Aims to improve groundwater management and encourage rainwater harvesting practices.
Success Stories
Rajasthan: The state has seen remarkable success in rainwater harvesting, particularly in Alwar district, where
traditional water harvesting structures like Johads have been revived.
Tamil Nadu: Chennai’s mandatory rainwater harvesting policy has significantly improved groundwater levels and
water availability.
Rainwater harvesting in India is a crucial step towards sustainable water management, addressing the challenges of
water scarcity and improving the resilience of communities to climate variability.
Water resources depletion
When the use of water is hampered by poor quality or when demand exceeds supply during a specific time period.
This phenomenon is known as Water Stress. It occurs due to the depletion of water resources. The causes that led to
the depletion of water resources are listed below:
Pollution: The majority of the wastewater from industries is dumped into these water sources. This ultimately
contaminates and pollutes water. This is yet another factor that contributes to the depletion of water supplies.
Saltwater Contamination: It occurs when freshwater sources deep in the earth are contaminated with saltwater. This
consequently decreases the supply of usable water.
Deforestation: Water depletion is primarily caused by deforestation. Large-scale-deforestation significantly reduces
the soil's ability to retain water, which has an impact on the water.
Poor storage of Water: A lot of rainwater is lost due to inadequate storage facilities. The ability to collect
rainwater and store it for later use has not advanced significantly technologically. Again, ignorance causes
significant water to be lost. Again, this results in depletion. Low precipitation: There has been a significant decline
in Precipitation and Distribution of Rainfall over time. Large-scale deforestation and abrupt climatic changes are the
main causes of this. These contribute to the decrease in water resources.
Urbanization is a phenomenon that both the government and the populace support. Widespread deforestation has
significantly impacted water resources.
Seepage: A significant amount of water is lost when the collected water is transported through the canals and pumps.
This water seeps into the ground. Again, this results in depletion.
Evaporation: As a result of climate change and global warming, more surface and groundwater is evaporating as a
result of the intense heat. Evaporation causes the water level in the reservoir and dams to decrease.
Agriculture: As agricultural activity increases day by day, more water is pumped for use in the process. More
groundwater is pumped for agricultural purposes because it is free. A bore well can be fixed to accomplish this. This
lowers the water levels that are causing its depletion.
Water usage in India is diverse and varies across different sectors, reflecting the country's large population,
agricultural dependency, industrial activities, and domestic needs. Here is a breakdown of water usage in India:
Agriculture:
Percentage: Approximately 80-90% of total water usage.
Usage: Mainly for irrigation of crops such as rice, wheat, and sugarcane. Traditional flood irrigation methods
dominate, though there is a growing shift towards more efficient practices like drip and sprinkler irrigation.
Domestic:
Percentage: Around 5-10% of total water usage.
Usage: Drinking, cooking, bathing, sanitation, and cleaning. Urban areas have higher per capita water consumption
compared to rural areas.
Industrial:
Percentage: About 2-5% of total water usage.
Usage: Various industries, including textiles, paper, chemicals, and steel, require water for processes, cooling, and
cleaning.
Power Generation:
Usage: Thermal power plants, which constitute a significant portion of India's electricity generation, require
substantial amounts of water for cooling purposes.
Environmental and Recreational:
Usage: Water is also used for maintaining natural ecosystems, parks, and recreational facilities.
Regional Variations
Northern India: Predominantly agricultural with extensive irrigation needs, particularly in states like Punjab,
Haryana, and Uttar Pradesh.
Southern and Western India: Diverse usage patterns, with significant industrial and domestic consumption in states
like Maharashtra, Tamil Nadu, and Karnataka.
Eastern India: High agricultural water use, especially in states like West Bengal and Odisha, where rice cultivation is
common.
Challenges
Water Scarcity:
Many parts of India face acute water shortages, especially during dry seasons. Over-extraction and climate change
exacerbate the problem.
Pollution:
Industrial discharge, agricultural runoff, and untreated sewage contaminate water sources, making it unsafe for
consumption and ecosystem health.
Inefficient Usage:
Traditional irrigation practices and lack of efficient water management techniques lead to substantial wastage.
Urbanization:
Rapid urban growth increases demand for water, straining existing supply systems and infrastructure.
