Alongside a severe shortage of oxygen and ICU beds during the current second wave of Coronavirus, India’s capital Delhi is now in the midst of a water crisis, compounded by the pandemic and rising heat.
According to Delhi Jal Board (DJB), the city-state gets 900 million litres of water per day from various water processing and filtration plants in the city. Over 90 percent of this water is sourced from various river canals such as Ganga Canal, Bhakhra and Sutlej Canal beside the river Yamuna that passes through the city.
Most of these canal systems are owned and operated by the irrigation departments of the neighbouring states of Uttar Pradesh, Punjab and Haryana.
On Friday, the Supreme Court refused to entertain DJB’s plea alleging shortage of water supply from Haryana and Punjab and asked it to approach the Upper Yamuna River Board with grievances.
Delhi could however greatly reduce its water dependence on other states if it starts storing the rainwater it receives during the monsoons.
This translates into annual rainwater of around 930 billion litres given Delhi’s surface area of 1484 sq km. This is nearly thrice the annual water supply capacity of DJB that stands at around 329 billion litres every year.
Rainwater harvesting at a large scale is not wishful thinking. This is how fort cities used to sustain themselves in the pre-modern era despite being situated at mountain tops, away from water sources.
Remember the scene in the movie Padmaavat, where Mewar’s King Ratan Singh decides to endure the siege of his fort city of Chittor by Alauddin Khilji when he learns from his minister that rainwater tanks in the fort could last months? That was the strength of water conservation in the bygone centuries.
Delhi can learn a lesson or two from water harvesting marvels of these five forts in different parts of India:
1. Rajgad Fort, Maharashtra: This fort was the capital of the Maratha Empire under the rule of Chhatrapati Shivaji Maharaj for almost 26 years. Spread over 1300 acres, the fort has large facilities for water storage, including two big lakes and 84 reservoirs and rock-cut cisterns. The natural gradient and slope of the fort were used to ensure that water from nearby springs and during rainy seasons was collected in tanks for use throughout the year. Water experts in the Maratha administration had the knowledge of water stored in the rocks, which were blasted to extract the water.
2. Mandu Fort, Madhya Pradesh: Located on the Vidhya ranges in Madhya Pradesh, this fort has no natural source of water but the fort city was inhabited by people for thousands of years. The fort has 1200 lakes, step-wells (baodis or baolis) and tanks that are full of water in monsoons even now and the water lasts through the year. A maze of channels throughout the fort ensured efficient collection and conservation of water.
3. Golconda Fort, Telangana: The Golconda Fort on a 400ft high hill in Hyderabad used Persian wheels that raised the water, which was then stored in overhead tanks at three different levels. This water was distributed throughout the fort through stone aqueducts and pipes, which are intact even today. The Qutb Shahi kings also built square stone towers at different levels that have water collection points at the top. This water was used in the fort’s fountains and for royal baths.
4. Nahargarh Fort, Rajasthan: Built by Maharaja Sawai Jai Singh in 1734, the fort has a water collection, harvesting and storage system which remains a technological marvel even today. The gradient of the hill is used to direct the flow of water and the canals and aqueducts carry rainwater to the two baolis in the fort. A smaller step well, called kund, is where the rainwater harvested from the fort is collected. The Roman-style aqueducts that connect mini watersheds at different heights in the hilly terrain remain one of Jaipur’s best-kept secrets.
5. Gingee or Senji Fort, Tamil Nadu: This fort, originally built in 1190 Ananta Kon of the Konar dynasty and modified by later rulers, used storage ponds and catchment tanks for rainwater harvesting. The fort used two systems for water supply - the first supplied perennial water to the inner fort from a pond which was fed by surface drainage. It used the principles of gravity flow and the siphon to carry water through earthen pipes to the palaces, tanks and fountains. The outer fort linked the water bodies to urban settlements around the fort.