Importance of Rain Water Harvesting in Cities and Urban Landscapes

Importance of Rain Water Harvesting in Cities and Urban Landscapes

Aug 14, 2021

Amplify Infra

70% of the planet earth is filled with water but only 2.5 percent of it is freshwater. The rest is saline and ocean-based. 1% of freshwater is accessible and which maximum is in the form of ice caps or glaciers.  Only 0.007% of the planet's water resources is drinkable and have to fuel and feed its 8 billion people. The water table below our ground is also fast depleting in the cities, we have to go 1000-2000 ft in cities like Hyderabad to get groundwater. Governments are moiling drinking water by connecting the rivers and altering their natural courses to create dams and reservoirs to satisfy our rainwater needs. All this has a substantial effect on our planet and future generations. We need to act now, it cannot be delayed further. There are many techniques like rainwater harvesting, greywater recycling, saline water recycling, etc. The most effective and cheapest with the least environmental effects is Rainwater harvesting.

 

 

 

A country like Singapore with 728 square kilometers of the area has no freshwater resources so it has a water agreement with Malaysia until 2061, the agreement was executed in 1962. Singapore has done a wonderful job of collecting all the rainwater effectively and every drop of greywater is recycled and reused. They have effectively planned to become self-sufficient by 2050 by tapping into rainwater harvesting projects. Hyderabad gets 718.1 mm of rainfall on an average year, this year it has received 1260 mm of rainfall that is 75% excess (data according to Telangana State Development Planning Society) due to the ill effects of climate change. We had no proper storage or drainage systems for the rainfall to get collected or drained so it resulted in the flooding of the city. Hyderabad is around 625 square kilometers, even if it gets an average rainfall of 718 mm in a year, and taking a run-off coefficient of concrete as 0.8

 

Formula for Catchment Area Calculation= Average Rainfall in a year (mm/Year) X Run-off Coefficient of the Surface Area X Area of the Surface (Square Meters)

 

= 718 X 0.8 X 625000000 = 3,90,500 Million Litres of Water

 

If we divide it by the population of Hyderabad around 100 Lakhs, each person will get 35900 liters of water per year. We need not capture the maximum rainwater like Singapore but we can devise ways to maximize the capture by having distributed rainwater harvesting tanks along with rainwater harvesting ponds and pits. Rain Water Harvesting tanks can be constructed at a low cost with a filtration system and the water can directly be used for consumption with minimum or no treatment.

 

Consider a house of 1000 Square feet (92 Square meters) roof area in Hyderabad. It can collect upto

Formula for Catchment Area Calculation= Average Rainfall in a year (mm/Year) X Run-off Coefficient of the Surface Area X Area of the Surface (Square Meters)

= 718 X 0.8 X 92 = 52, 845 Litres of Rain Water Can be collected.

 

 Even if he collects half of it he will need a tank of 25,000 Litres and the rest 27,000 Litres can be diverted to the rainwater harvesting pit to recharge the groundwater levels. He will need a tank area of 9 ft x 7 ft x 12 ft ( Length x Breadth x Depth), it can be done at an affordable cost. In summer a water tanker of 5000 liters costs around Rs. 4000, he can recover the cost in 3 years and gain a lifetime of savings as the scarcity of water goes up.

 

Amplify Infra constructs rainwater harvesting tanks along with all new constructions where it executes turnkey home construction projects in Hyderabad and Vizag. We can also provide the rainwater harvesting tank construction services to already built or upcoming apartments and individual homes. For more information please visit our website www.amplifyinfra.com

 

 

 

Written By

Yashwant Ram Meesala

CEO

Amplify Infra