Introduction to Rain water harvesting

Rainwater harvesting is a key practice in environmental engineering that involves collecting and storing rainwater through various methods. These can include systems like rain barrels, rooftop collection, surface and subsurface systems, and large storage tanks. The harvested water can then be used for different purposes, such as:

• Agriculture: To water crops and support farming.
• Drinking: After proper filtration, it can provide clean drinking water.
• Non-potable uses: For activities like cleaning, irrigation, or flushing.

The problem of water scarcity is becoming more severe day by day in many regions due to the effects of climate change. Whether in India or elsewhere, droughts are becoming more common and it is becoming difficult to depend on traditional water sources. This is why it is very important to find sustainable solutions like rainwater harvesting. By harvesting rainwater, we can reduce our dependence on overused water supplies and create a more sustainable way to meet our water needs.

Important Points

• Rainwater harvesting conserves groundwater ensuring a sustainable water supply.
• Collecting rainwater during monsoons creates a reserve for dry months.
• It reduces pressure on existing water systems & promotes eco-friendly practices.

Why Not Rainwater Harvesting?

Let’s not forget the history of rainwater harvesting in India

Water scarcity and poor water quality are serious issues faced by both urban and rural areas in – India. Even large cities Such as Delhi have recently experienced major water crises, highlighting the widespread nature of the problem. As water scarcity worsens, water bills continue to rise, making it increasingly difficult for people to afford clean water. Despite the growing need, it’s surprising that rainwater harvesting is not more widely adopted, especially when it is a simple, effective solution that is often taught in schools and colleges Find out why rainwater harvesting is so important here.

Indeed, we are cognizant that only a mere 2-3% of the Earth’s total water constitutes freshwater. This stark reality underscores the utmost importance of rainwater harvesting as a vital practice to harness this precious freshwater resource for drinking and other essential purposes. Let’s delve into history before exploring modern technology.(Research Paper)

Well-Rainwater harvesting is not a recent innovation in India – In fact, this is an ancient and traditional method. About 6000 years ago, during the Harappan civilization, rainwater was collected in wells. The designs of traditional structures vary from state to state and even from region to region depending on the monsoon patterns.

According to Archaeological And Historical Records, Indians were experts in building Dams, Lakes, and irrigation systems during the reign of Chandragupta Maurya [392-297 BCE]. India’s largest artificial lake was built by Raja Bhoj of Bhopal in the 11th century AD. It covered an area of more than 65,000 hectares and was fed by 365 rivers and springs. The Indians had developed indigenous techniques of diverting river water into artificial channels for agriculture through simple engineering structures.

Another historical account of rainwater harvesting lies in the practices of farmers in Baluchistan (now part of Pakistan, Afghanistan, and Kutch in India). They began collecting rainwater for irrigation and various uses, showcasing the simple infrastructure modifications needed to initiate rainwater harvesting.

Furthermore, rainwater harvesting was implemented by Chola kings, marking a significant historical stride in India. Rainwater collected from the Britadeeswarar temple in Baragwanath Nagar, Thanjavur, India, was later stored in the Shivganga pond during the Chola dynasty.

During the years 907–956 CE, the Viranam tank was constructed in the Cuddalore area of Tamil Nadu to store water for both drinking and agricultural purposes. This historical evidence highlights the enduring importance and practice of rainwater harvesting throughout different regions and periods in India.

What is the Need of Rain water Harvesting in India?

As climate change continues to intensify – India is increasingly facing water-related issues. Many states are projected to encounter severe water crises in the near future. Recently, Delhi has been experiencing a significant water crisis due to falling water levels. It is very important to revitalize and rebuild the water management structures that were used in previous centuries. While many of these structures can still be utilized but they need some modifications to be effective.

• Water Scarcity: 80% of districts in India face water scarcity.
• Groundwater Depletion: Over 50% of wells are declining, threatening water security.
• Uneven Rainfall: Erratic monsoons lead to floods and droughts.
• Agricultural Dependency: 70% of water is used for agriculture; efficient use is crucial.
• Population Pressure: India’s growing population strains existing water resources.
• Climate Change Impact: Changing climate patterns disrupt traditional water sources.
• Urbanization Challenges: Rapid urban growth demands innovative water solutions. Rainwater harvesting addresses these pressing issues, providing a sustainable water source and building resilience. Click here to read in detailed.

What Are the Objectives of Rainwater Harvesting?

1. Water Conservation: Preserve and optimize the usage of rainwater, reducing dependency on external water sources.
2. Groundwater Recharge: Replenish depleting groundwater levels by allowing rainwater to percolate into the ground.
3. Mitigate Floods and Erosion: Control excess rainwater, minimizing flooding and soil erosion through proper channeling and storage.
4. Sustainable Agriculture: Support agriculture by providing a reliable source of water for irrigation during dry spells.
5. Augment Water Supply: Supplement traditional water sources to meet the growing demand for water, especially in urban areas.
6. Environment-Friendly Practices: Promote eco-friendliness by reducing the strain on ecosystems and lowering the carbon footprint associated with centralized water supply.
7. Community Resilience: Enhance community resilience by ensuring a consistent water supply, especially in drought-prone regions.

• Urban Water Management: Optimize water use in urban areas, reducing the burden on municipal water supply systems.

• Climate Change Adaptation: Act as an adaptive measure to climate change by providing a decentralized and dependable water source.

• Education and Awareness: Raise awareness and educate the public about sustainable water management and conservation practices.

FAQ’s

What is rainwater harvesting?

Rainwater harvesting is collecting and storing rain using methods like rain barrels, surface and rooftop collection. It serves various purposes like agriculture and drinking.

Why is rainwater harvesting important?

It’s vital due to increasing water scarcity and climate change. Only 2-3% of Earth’s water is freshwater, making rainwater harvesting crucial to preserve this resource.

How long has it been practiced in India?

Rainwater harvesting dates back more, than 6000 years in India, seen during the Harappan civilization, evolving with regional monsoons.

How does it help during droughts?

Rainwater harvesting provides a reliable water source during droughts, replenishing groundwater and easing the strain on conventional sources.

Can it reduce water bills?

Yes, it significantly reduces water bills by supplementing conventional sources in both cities and villages.

What historical evidence supports it in India?

Historical and archaeological records reveal ancient expertise in water management through structures, dams, and irrigation systems.

How much water can be collected?

Rainwater harvesting can yield millions of litres annually from an acre of land with average rainfall.

Is it eco-friendly?

Yes, it’s eco-friendly, reducing strain on ecosystems and promoting sustainable water management.