Water Harvesting – Definition, Importance, Methods, Limitations

Water is one of the most essential natural resources that are present on this planet. Water plays a major role on the earth. Water covers more than 70% of the earth’s surface. It is essential in human, aquatic, and animal life. Water covers the everyday essentials of humans and comes in free form. About 60 to 70% of the human body covers with water. However, it is a basic ingredient of any living being. According to the Atharva Veda, life is believed to be first evolved and nourished in water. The Rig Veda says water has a lifesaving medicinal quality, so it needs to be conserved. Water is also required in large quantities for different sectors like irrigation, industries, transportation, hydroelectricity plants, and household activities. All extraordinary civilizations began and flourished close to water bodies. In the 21st hundred years, we can never again reject that water is turning out to be increasingly scanter continuously. Taking into account that water is the key element that empowers all life to make due and flourish, the preservation of water has turned into a significant part of a greener tomorrow. The world requires a minimal expense clean stockpile of water into the indefinite future. Furthermore, there could be no greater way to this than water harvesting. Many regions of the planet are confronting high to outrageous water stresses. This pressure is because of a shortage of underground water, a botch of existing water bodies, expansion in stream water contamination by permitting modern and metropolitan poisons to stream into streams, absence of water reusing, no astute use, and wastage of water. Consequently, there is a need for a shrewd water management system.

Water Harvesting

The term water harvesting alludes to the collection of rainstorms from a catchment to give water to humans, animals, or agriculture use. The water in this manner gathered can either be used right away, with respect to the water system, or be put away in over-the-ground lakes or in subsurface repositories, like storage or shallow springs, for ensuing use. Thusly, water harvesting is an old practice that has empowered a few social orders to stay alive in semiarid and dry regions that were meager or inaccessible.

Major Sources for Rainwater Harvesting 

• Roofs: Buildings with impenetrable rooftops give viable water for different purposes.
• Cleared and Unpaved Areas: Landscapes, open fields, parks, stormwater channels, streets, and other open regions can be actually used to reap the overflow. The primary benefit of involving the ground as a gathering surface is that water can be gathered from a bigger region. This is especially favorable in areas of low precipitation.
• Waterbodies: Lakes, tanks, and canals are valuable stores of water. The collected water cannot exclusively be utilized to meet the water prerequisites of the city; however, it likewise re-energizes groundwater springs.
• Stormwater Drains: Those districts which have a legitimate organization of stormwater channels give straightforward and savvy implications for harvesting water.

Water Harvesting can be embraced in various ways

• Catching overflow from roofs
• Catching overflow from neighborhood catchments
• Catching occasional floodwaters from local streams
• Rationing water through watershed the executives

These methods can fill the accompanying needs

• Serves drinking water.
• Serves water for the irrigation system.
• Increment in groundwater re-energize.
• Decrease stormwater releases, metropolitan floods, and over-burdening of sewage treatment plants.
• Decrease seawater entrance in seaside regions.

How an individual can harvest water?

An individual or individuals can easily harvest water by using their houses as an advantage of capturing runoff rainwater from rooftops.

• Rooftops alignment setup: Setups required for the water harvesting system in the house
• Catchment region/gutter setup: The more the slants of catchment regions, the speedier the overflow and thus quicker assortment of water. The rate should be controlled utilizing plastic sheets, black-top, or tiles alongside slant.
• Conveyance structures: These designs are the necessary resources to move the gathered water from the catchment surface to the putting away vessels. (Pipelines, valves, etc.)
• Collection tanks: The gathered water from the catchment region is expected to be gathered and put away in appropriate storage.
• Filters: To make the gathered water usable, it should be tainting-free, safe, and economical. The accompanying separating framework might be utilized, for example, sand gravel filter, charcoal filter, and PVC pipe filter, and sponge filter.
• Pumps: A pumping system is required to force collected filter water from the main storage tank to an overhead tank of the house for household purposes.

Component required

1. Rooftop catchment/ gutter setups.
2. Convenient system (PVC pipes, tubes, adjustment valves, diversion valves, sealing balls, etc.)
3. Filtering system.
4. Collection and storage equipment (galvanized tanks, Ferro cement tanks, concrete tanks, etc.)
5. Pumping system.
6. Tools and other equipment for the construction setup.

Methods of water harvesting

Traditional methods:

Kund’

In the sandy towns of the Thar Desert, a clever arrangement of water harvesting is known as Kund’s or Kundis. Kund is the neighborhood’s name given to a covered underground tank, that was grown essentially for handling drinking water issues. The Kund comprises a saucer-molded catchment region with a delicate slant towards the middle where a tank is arranged. Openings or gulfs for water to go into the tank are typically monitored by a wire lattice to forestall the section of drifting flotsam and jetsam, birds, and reptiles. The top is normally covered with a top from where water can be really long with a can. Kunds are all-around round in shape, with little variety between the depth and width which goes from 3-4.5 m.

Saza Kuva

An open well with different proprietors, saza kuva is the main wellspring of the water system in the Aravalli slopes in Mewar, eastern Rajasthan. The name saza means to partner. Harva, a man with exceptional abilities in groundwater identification, helps fix the site. Saza kuva is developed by farmers. The dirt recovered to make the well pit is utilized to develop a tremendous round establishment or a raised stage slanting away from the well. The first is worked to accommodate the rehat, a customary water-lifting gadget; the slanting stage is for the chada, in which bison are utilized to lift water. 

Bamboo Drip Irrigation

In Meghalaya, one more procedure for the tapping of stream and spring water is pervasive in which bamboo is utilized to water crops. It is amazing to such an extent that around 18-20 liters of water entering the bamboo pipe framework each moment gets shipped north of a few hundred meters lastly gets decreased to 20-80 drops each moment at the site of the plant. The ancestral ranchers of Khasi and Jaintia slopes utilize the 200-year-old framework. The bamboo drip water system is typically used to water the betel leaf or dark pepper crops planted in Arecanut plantations.

Pat

Pats are the unique systems designed in the Bhitada village of Madhya Pradesh. This framework was designed on the basis of the landscape to redirect water from quick streaming slope streams into water system channels called pats. The redirection bunds across the stream are made by stacking up stones and afterward fixing them with teak leaves and mud to make them sealed. The pat channel needs to haggle little nullahs that join the stream now and again, and furthermore sheer bluffs prior to arriving at the fields. These segments perpetually washed away during the rainstorm.

Modern methods of water harvesting

Surface Water harvesting

The vast majority of the cutting-edge houses have it. It comprises a downpour drain and a seepage pipe associated with it. It helps in gathering in one spot all the water that the top of a house gets. In the event that you don’t have it then your rooftop will disperse away from the water and it would become difficult to gather it. Example: Rooftop Rainwater harvesting.

Re-energizing Borewells and Tube wells

The borewells and tube wells for the most part get re-energized by the underground water. Be that as it may, you can likewise utilize your gathered water to re-energize them. Simply interface the downpour seepage line to a channel that prompts the borewell. It won’t just assist you it with willing additionally help individuals around you. The water gathered by the borewells leaks through holes in its walls and it recharges the groundwater. 

Ground water recharging

One can expand the level of groundwater by re-energizing strategies. To do this, first, make a pit in the ground, and fill it with sand and rocks. On top of the pit, make a chamber for an assortment of water, which will arrive through the lines of structure housetops. One more method for doing this is to construct a well in the ground and cover it with substantial fronts of fitting thickness so that individuals and vehicles could move without limitation on top. Channelize the water through pipes into the well.

Groundwater Dams

The essential rule of the groundwater dam is that water is put away underground other than at the surface. The fundamental benefits of water stockpiling in groundwater dams are that dissipation misfortunes are considerably less for water put away underground. and another advantage is it has less prone to contamination and less raise or entry of parasites. The issue of submergence of land which is typically connected with surface dams is absent with sub-surface dams.

Sub-surface Dam

A Sub-surface dam captures or blocks the progression of spring and diminishes the variety of the level of the groundwater table upstream of the dam. It is fabricated completely under the ground.

Sand Storage Dam

It is built over the ground. Sand and soil particles shipped during times of high stream are permitted to store behind the dam, and water is put away in these dirt stores. The sand stockpiling dam is developed in layers to permit sand to be kept and better material is washed downstream A groundwater dam can likewise be a mix of these two kinds. While developing a sub-surface dam in a waterway bed, one can build the capacity volume by letting the mass of the Dam ascend over the surface, hence causing extra gathering of silt. Likewise, when a sand-stockpiling dam is built, it is important to exhume a channel in the sand bed to arrive at bedrock, which can be utilized to make a sub-surface dam as well.

Rain pod

David L Hote of France developed the rain pod. It permits you to gather water with its novel structure and features. It works like a downpour barrel, the calculated Rain unit gathers water in an enormous tank and, standing taller than a man, has the level and reach to cover a huge region around it, sprinkling the region utilizing only gravity.

Lotus Flower system

The framework has been created with the joint effort of Green Cross Italia. its inspiration was taken from a lotus flower. Very much like a lotus blossom, the framework opens its copper petals during storms and keeps them shut during the other piece of the year to safeguard the virtue of water. The framework can be constructed utilizing nearby materials like cement, copper, and wood.

Watree

Watree is a water gathering framework that closely resembles an umbrella flipped around. The framework is intended to be put in clear areas and parks. The framework gathers every one of the valuable drops that fall on it and moves it to tanks situated in an alternate area. During summers when there is a scarcity of water, the capacity tanks can siphon water back through a progression of underground lines.

The advantages of the water harvesting system

1. Less expense.
2. Spending money on water bills can be minimized.
3. Reduces water scarcity.
4. Diminishes the requirement for imported water.
5. Advances in both water and energy protection.
6. Works on the quality and amount of groundwater.
7. Doesn’t need filtration for basic and gardening purposes.
8. This innovation is basic, simple to introduce, and work.
9. It lessens soil erosion, rainwater runoff, flooding, and contamination of surface water with composts, pesticides, metals, and different dregs.
10. It is a great source of water for landscape irrigation without adding any chemical substances.

Drawbacks of the water harvesting process

1. Maintenance and upkeep are required.
2. Requires a few specialized abilities for establishment.
3. less and no precipitation can restrict the stockpile of water.
4. If the structure installed is not accurate, it might draw in mosquitoes and other waterborne sicknesses.
5. Storage limits for the storing tanks. During heavy rains and high overflows, it makes problematic.

Conceptual Question

Question 1: What is NWHN?

Answer:

National Water Harvesters Network (NWHN) is a broad organization that tends to water issues through individuals from the different foundations in India and abroad. The individuals from NWHN are principally experts, civil servants, grassroots functionaries, intrigued residents, and every one of those serious about creating or undertaking a water gathering program. The organization locations and features the neighborhood issues and the conventional frameworks connecting with water gathering to add the reason for local area-based water management.

Question 2: What are the objectives of rainwater harvesting?

Answer: Some of the objectives of rainwater harvesting are:

• Increment volume of water bodies: During the dry season, there is very little or no downpour. Because of this, the water bodies like lakes, streams, and so on are dried. By utilizing these strategies, the water bodies can be re-energized, and their volume can be expanded.
• Stopping floods and soil erosion: By putting away water, it decreases the surface overflow. This lessens the surface disintegration. By catching water in repositories, the flood issue in huge rainfalls is likewise lessened.
• Preventing over-usage of groundwater:  Because of the increasing population, the degree of underground water is diminishing quickly. By utilizing rainwater, the usage of groundwater can be decreased.
• Saving money: Money can be saved on water bills and importing of water. Pumping up underground water is more expensive than that water collection. Thus, the utilization of water sets aside cash.

Question 3: What is the importance of water harvesting?

Answer:

Precipitation Pattern and Rain Potential assume a definitive part in storage or re-energizing water in a specific district. The sub-surface geography additionally assumes a significant part in settling on this choice. In some places, the surface is impermeable re-energizing won’t be attainable. Thus, it would be ideal to decide on capacity. Where the groundwater is saline or not of consumable guidelines, the substitute framework could be that of storing rainwater. Water harvesting is the strategy of a social affair or aggregating and putting away of water. Water harvesting gives drinking water, homegrown water, water for domesticated animals, water for the little water system,s and a method for expanding groundwater levels.

Question 4: How are water harvesting practices around the world?

Answer:

It has become essential for water specialists across various nations to take on water harvesting and protection procedures.

• Rooftop rainwater harvesting is ongoing in China and Brazil. Gansu province in China and semi-arid northeast Brazil have the undergoing largest rooftop rainwater harvesting projects.
• In Bermuda, the law requires all new development to incorporate water gathering properly for the occupants.
• The U.S. Virgin Islands have a comparative regulation.
• In Senegal/Guinea-Bissau, the houses of the Diola-individuals are continuously equipped with homebrew rainwater harvesters made from nearby, natural bio material.
• In the UK, water butts are many times tracked down in homegrown nurseries to gather water which is then used to water the nursery.

Question 5: What are the factors influencing the limit of water harvesting?

Answer:

A few factors assume a crucial part in how much water is harvested. A portion of these factors are:

• The quantum of spillover.
• Elements of the catchments.
• Influence on the climate.
• Accessibility of the innovation.
• The limit of the stockpiling tanks.
• Sorts of the rooftop, its alignment, and its materials.
• The recurrence, amount, and nature of the precipitation.
• The speed and simplicity with which the water infiltrates through the soil to re-energize the groundwater.

Question 6: What type of filters can be installed in water harvesting system?

Answers:

Filters are very important in the water harvesting systems to make collected water usable and free from other impurities. Some of them are: 

• Sand filters: Sand filters are normally the most generally utilized channels. These block brickwork structures. Little stones and sand are filled in this construction to act as a separating medium. Every one of these separating media is made of one channel layer. Every last one of these layers is partitioned utilizing a wired network.
• Charcoal filters: Charcoal filters are drum molded structures. These are topped off with charcoal notwithstanding little stones, significantly smaller gravels, and sand layer by layer. Here additional layers are isolated utilizing a wired network.
• PVC filters: PVC filters are comprised of PVC pipes loaded up with sand and rock isolated by a layer of rock.
• Sponge filters: Sponge filters are the most straightforward and modest water channel. It comprises a PVC drum with a sponge layer halfway. It is proper for house use.