Rainwater Harvesting- History of Rainwater Harvesting,current use of Rainwater harvesting,Benefits of Rainwater Harvesting

Rainwater harvesting is the accumulation and storage of rainwater for reuse on-site, rather than allowing it to run off. Rainwater can be collected from rivers or roofs, and in many places, the water collected is redirected to a deep pit (well, shaft, or borehole), aquifer, a reservoir with percolation, or collected from dew or fog with nets or other tools. Its uses include water for gardens, livestock, irrigation, domestic use with proper treatment, indoor heating for houses, etc. The harvested water can also be used as drinking water, longer-term storage, and for other purposes such as groundwater recharge.

The Need of Water

Why collect rainwater? Civilizations, settlements, countries, and empires of the past had basic needs to survive just like we do in the present day. Water, food, and shelter were a continuous struggle to provide, especially in dry climates where water was scarce.

But there was a solution and people of the past came up with brilliant methods of solving these issues. One idea that became a sustaining source throughout thousands of years was rainwater collection and diversion.

History of Rainwater Harvesting

Obviously, it is nearly impossible to trace back to which civilization used the method of rainwater harvesting first, but evidence shows that different types of rainwater collection systems were used in 2000 BC in India, Mesopotamia, China, and modern day Israel.

The basic design of these systems often involved a large rock formed into a basin using clay and other rocks to seal it from leaking. And then, using different diversion tactics, water would be stored and used for drinking, washing, agriculture and more.

The middle east has a rich history in the rainwater harvesting timeline. Dating back to 2000 B.C., people in the Negev Desert, which is modern-day Israel, survived by capturing water from the hillside and storing it in Cisterns.

Around 300 BCE, farming communities in Balochistan (now located in Pakistan, Afghanistan, and Iran), and Kutch, India, used rainwater harvesting for agriculture and many other uses. Rainwater harvesting was done by Chola kings as well. Rainwater from the Brihadeeswarar temple (located in Balaganpathy Nagar, Thanjavur, India) was collected in Shivaganga tank.^[6] During the later Chola period, the Vīrānam tank was built (1011 to 1037 CE) in the Cuddalore district of Tamil Nadu to store water for drinking and irrigation purposes. Vīrānam is a 16-km-long tank with a storage capacity of 1,465,000,000 cu ft (41,500,000 m³).

Rainwater harvesting was also common in the Roman Empire. While Roman aqueducts are well-known, Roman cisterns were also commonly used and their construction expanded with the Empire. For example, in Pompeii, rooftop water storage was common before the construction of the aqueduct in the 1st century BC. This history continued with the Byzantine Empire, for example the Basilica Cistern in Istanbul.

Though little-known, for centuries the town of Venice depended on rainwater harvesting. The lagoon which surrounds Venice is brackish water, which is not suitable for drinking. The ancient inhabitants of Venice established a system of rainwater collection which was based on man-made insulated collection wells. Water percolated down the specially designed stone flooring, and was filtered by a layer of sand, then collected at the bottom of the well. Later, as Venice acquired territories on the mainland, it started to import water by boat from local rivers, but the wells remained in use, and were especially important in time of war when access to the mainland water could be blocked by an enemy.

Current uses

India

• Tamil Nadu was the first state to make rainwater harvesting compulsory for every building to avoid groundwater depletion. The scheme was launched in 2001 and has been implemented in all rural areas of Tamil Nadu. Posters all over Tamil Nadu including rural areas create awareness about harvesting rainwater. TN Govt site. It gave excellent results within five years, and slowly every state took it as a role model. Since its implementation, Chennai had a 50% rise in water level in five years and the water quality significantly improved.
• Karnataka: In Bangalore, adoption of rainwater harvesting is mandatory for every owner or the occupier of a building having the site area measuring 60 ft (18.3 m) × 40 ft (12.2 m) and above and for newly constructed building measuring 30 ft (9.1 m) × 40 ft (12.2 m) and above dimensions. In this regard, Bangalore Water Supply and Sewerage Board has initiated and constructed “Rain Water Harvesting Theme Park” in the name of Sir M. Visvesvaraya in 1.2 acres (4,900 m²) of land situated at Jayanagar, Bangalore. In this park, 26 different type of rainwater harvesting models are demonstrated along with the water conservation tips. The auditorium on the first floor is set up with a "green" air conditioning system and will be used to arrange the meeting and showing of a video clip about the rainwater harvesting to students and general public. An attempt has been made at the Department of Chemical Engineering, IISc, Bangalore to harvest rainwater using upper surface of a solar still, which was used for water distillation
• In Rajasthan, rainwater harvesting has traditionally been practiced by the people of the Thar Desert. Many ancient water harvesting systems in Rajasthan have now been revived. Water harvesting systems are widely used in other areas of Rajasthan, as well, for example the chauka system from the Jaipur district.
• Maharashtra: At present, in Pune, rainwater harvesting is compulsory for any new housing society to be registered.
• In Mumbai, Maharashtra, rainwater harvesting is not mandatory. The Mumbai City council is planning to make rainwater harvesting mandatory for large societies.

South Africa

The South African Water Research Commission has supported research into rainwater harvesting. Reports on this research are available on their "Knowledge Hub". Studies in arid, semiarid, and humid regions have confirmed that techniques such as mulching, pitting, ridging, and modified run-on plots are effective for small-scale crop production. hydrofracturing has regularly been used to improve the performance of water boreholes. From 1990 to 1992, 170 boreholes had been hydrofractured.

United Kingdom

In the United Kingdom, water butts are often found in domestic gardens and on allotments to collect rainwater, which is then used to water the garden. However, the British government's Code For Sustainable Homes encouraged fitting large underground tanks to newly built homes to collect rainwater for flushing toilets, watering, and washing. Ideal designs had the potential to reduce demand on mains water supply by half. The code was revoked in 2015.

Benefits of Rainwater Harvesting

The collection of rainwater and harvesting it for everyday use has an ample number of exciting benefits. Let’s take a look and discover some of those benefits.

Provides backup source of water

There are many uncertainties in water supply systems. Droughts may lead to shortage of water. Destruction of water supply systems may occur at specific locations. Major repairs and maintenance in water companies happen sporadically. All these variables lead to unavailability of water in your home. So, installing rainwater harvesting system is the best course of action to continue enjoying water supply in case any of the above variables occur.

The collected rainwater can be used for many different purposes around the home. This includes laundry, washing dishes and more. This would prevent groundwater depletion and augment ground water table.

Ecological benefit

The ecological benefits of rainwater harvesting are immense. An activity like flushing the toilet, for instance, attributes to about 35% of home water usage. Add up the amount of water used to irrigate the lawn, do laundry, wash cars and the total amount water used is simply astronomical. For businesses, more so hospitality establishments that accommodate a big number of guests in a single location, require a lot of water to satisfy customers. Rainwater harvesting will simply help to fill this gap.

The ecological benefit rainwater harvesting systems bring is that there will be a significant reduction in the amount of water used from the mains. This, ideally, means that water companies will not have to artificially pump in water from rivers and lakes. This will help minimize the possibility of rivers drying up. Another great ecological benefit of rainwater harvesting systems is that they help reduced the load placed upon drainage systems, minimizing the impacts of flooding by funneling the runoff water into large tanks for recycling.

Easy to maintain

Rainwater harvesting systems are considerably easy to maintain since they are not utilized for drinking, cooking or other sensitive uses. This means that they will not need installation of purification systems, which are usually expensive.

Rainwater harvesting systems are cost effective, provide high quality water, reduce dependence on wells. The surplus rainwater can also be used to recharge ground water aquifer through artificial recharge techniques.

Reduces erosion and flooding around buildings

Most buildings that utilize rainwater harvesting systems have a built-in catchment area on top of the roof, which is capable of collecting vast amounts of water in case of rain storms. It helps to reduce soil erosion as by capturing rainwater, the flow of storm water is reduced which can also prevent urban flooding. If the water were not collected efficiently, it could have resulted in serious soil erosion and flooding around the house.

Requires low upfront capital investment

Installation of rainwater harvesting system is not that expensive, plus it’s a one-time installation, and that’s it. The only routine maintenance required is cleaning out the tank. You will probably hire an expert technician to install the system for you. The technician won’t quote a high price, plus he will offer free advice on the best rainwater system to buy. He will also help out when buying the system to ensure you get the best quality rainwater harvesting system. When you sum up the overall cost of installing the system, you’ll find that it’s actually manageable.

Once you begin using rainwater you will also appreciate a reduced amount of water consumption in the home, thus all of your utility bills will greatly shrink in size. How incredible would it be to slash as much as 50 to 60% off of your water bill each month? No complaints with having additional money in the pocket each and every month.

System Setup

Rainwater harvesting systems can range in complexity, from systems that can be installed with minimal skills, to automated systems that require advanced setup and installation. The basic rainwater harvesting system is more of a plumbing job than a technical job, as all the outlets from the building's terrace are connected through a pipe to an underground tank that stores water.

Systems are ideally sized to meet the water demand throughout the dry season, since it must be big enough to support daily water consumption. Specifically, the rainfall capturing area such as a building roof must be large enough to maintain adequate flow of water. The water storage tank size should be large enough to contain the captured water. For low-tech systems, many low-tech methods are used to capture rainwater: rooftop systems, surface water capture and pumping the rainwater that has already soaked into the ground or captured in reservoirs and storing it in tanks (cisterns).

Before a rainwater harvesting system is built, use of digital tools is useful. For instance, to detect if a region has a high rainwater harvesting potential, rainwater-harvesting GIS maps can be made using an online interactive tool, or, to estimate how much water is needed to fulfill a community's water needs, the Rain is Gain tool helps. Tools like these can save time and money before a commitment to build a system is undertaken, in addition to making the project sustainable and long lasting.

Conclusion

Rainwater harvesting is something that thousands of families across the world participate in, and you could be the next to enjoy the multitude of benefits offered with rainwater harvesting. It is an easy, simple and worthwhile process, so it is only in your best interest to take a look at rainwater harvesting and its benefits to your home. You may discover many surprises and things that you did not know along the way!