Rainwater harvesting

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configuration of domestic rainwater harvesting system in Uganda. RWH-image.jpg
configuration of domestic rainwater harvesting system in Uganda.

Rainwater harvesting (RWH) is the collection and storage of rain, rather than allowing it to run off. Rainwater is collected from a roof-like surface and redirected to a tank, cistern, deep pit (well, shaft, or borehole), aquifer, or a reservoir with percolation, so that it seeps down and restores the ground water. Rainwater harvesting differs from stormwater harvesting as the runoff is typically collected from roofs and other area surfaces for storage and subsequent reuse. [2] : 10  Its uses include watering gardens, livestock, [3] irrigation, domestic use with proper treatment, and domestic heating. The harvested water can also be used for long-term storage or groundwater recharge. [4]

Contents

Rainwater harvesting is one of the simplest and oldest methods of self-supply of water for households, having been used in South Asia and other countries for many thousands of years. [5] Installations can be designed for different scales, including households, neighborhoods, and communities, and can also serve institutions such as schools, hospitals, and other public facilities. [6]

Uses

Rainwater capture and storage system, Mexico City campus, Monterrey Institute of Technology and Higher Education 03242012Taller sostenibilidad lore037.jpg
Rainwater capture and storage system, Mexico City campus,Monterrey Institute of Technology and Higher Education
Cistern, Mission District, San Francisco, California Cistern in the Mission District, San Francisco, California.jpg
Cistern, Mission District, San Francisco, California
Rainwater capture, Gibraltar East Side, 1992 Gibraltar East Side Water Catchments in 1992.jpg
Rainwater capture, Gibraltar East Side, 1992
Home, with rain collection jars on roof, Panarea, Aeolian Islands, north of Sicily, Italy Panarea01.jpg
Home, with rain collection jars on roof, Panarea, Aeolian Islands, north of Sicily, Italy
Rainwater harvesting and hand washing system for a toilet in Kenya. UDDT with rainwater harvesting (3441547910).jpg
Rainwater harvesting and hand washing system for a toilet in Kenya.
Rainwater harvesting in Burkina Faso Rainwater harvesting in Burkina Faso (2957138439).jpg
Rainwater harvesting in Burkina Faso
Plastic Pond for Rainwater Harvesting, Nepal, 2013 Rainwater Harvesting and Plastic Pond 2.JPG
Plastic Pond for Rainwater Harvesting, Nepal, 2013
Rainwater harvesting system, Kiribati Rainwater harvesting systems in Kiribati (10715703914).jpg
Rainwater harvesting system, Kiribati

Domestic use

Rooftop rainwater harvesting is used to provide drinking water, domestic water, water for livestock, water for small irrigation, and a way to replenish groundwater levels.

Kenya has already been successfully harvesting rainwater for toilets, laundry, and irrigation. Since the establishment of the 2016 Water Act, Kenya has prioritized regulating its agriculture industry. [9] Additionally, areas in Australia use harvested rainwater for cooking and drinking. [10] Studies by Stout et al. on the feasibility of RWH in India found it most beneficial for small-scale irrigation, which provides income from produce sales, and for groundwater recharge. [10]

Agriculture

In regards to urban agriculture, rainwater harvesting in urban areas reduces the impact of runoff and flooding. The combination of urban 'green' rooftops with rainwater catchments have been found to reduce building temperatures by more than 1.3 degrees Celsius. Rainwater harvesting in conjunction with urban agriculture would be a viable way to help meet the United Nations Sustainable Development Goals for cleaner and sustainable cities, health and wellbeing, and food and water security (Sustainable Development Goal 6). The technology is available, however, it needs to be remodeled in order to use water more efficiently, especially in an urban setting.

Missions to five Caribbean countries have shown that the capture and storage of rainwater runoff for later use is able to significantly reduce the risk of losing some or all of the year's harvest because of soil or water scarcity. In addition, the risks associated with flooding and soil erosion during high rainfall seasons would decrease. Small farmers, especially those farming on hillsides, could benefit the most from rainwater harvesting because they are able to capture runoff and decrease the effects of soil erosion. [11]

Many countries, especially those with arid environments, use rainwater harvesting as a cheap and reliable source of clean water. [12] To enhance irrigation in arid environments, ridges of soil are constructed to trap and prevent rainwater from running down hills and slopes. Even in periods of low rainfall, enough water is collected for crops to grow. [13] Water can be collected from roofs, dams and ponds can be constructed to hold large quantities of rainwater so that even on days when little to no rainfall occurs, enough is available to irrigate crops.

Industry

Frankfurt Airport has the largest rainwater harvesting system in Germany, saving approximately 1 million cubic meters of water per year. The cost of the system was 1.5 million dm (US$63,000) in 1993. This system collects water from the roofs of the new terminal which has an area of 26,800 square meters. The water is collected in the basement of the airport in six tanks with a storage capacity of 100 cubic meters. The water is mainly used for toilet flushing, watering plants and cleaning the air conditioning system. [14]

Rainwater harvesting was adopted at The Velodrome – The London Olympic Park – in order to increase the sustainability of the facility. A 73% decrease in potable water demand by the park was estimated. Despite this, it was deemed that rainwater harvesting was a less efficient use of financial resources to increase sustainability than the park's blackwater recycling program. [15]

Technologies

Traditionally, stormwater management using detention basins served a single purpose. However, optimized real-time control lets this infrastructure double as a source of rainwater harvesting without compromising the existing detention capacity. [16] This has been used in the EPA headquarters to evacuate stored water prior to storm events, thus reducing wet weather flow while ensuring water availability for later reuse. This has the benefit of increasing water quality released and decreasing the volume of water released during combined sewer overflow events. [17] [18]

Generally, check dams are constructed across the streams to enhance the percolation of surface water into the subsoil strata. The water percolation in the water-impounded area of the check dams can be enhanced artificially manyfold by loosening the subsoil strata and ANFO explosives as used in open cast mining. Thus, local aquifers can be recharged quickly using the available surface water fully for use in the dry season.

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. There are common components that are installed in such systems, such as pre-filters (see e.g. vortex filter), drains/gutters, storage containers, and depending on whether the system is pressurized, also pumps, and treatment devices such as UV lights, chlorination devices and post-filtration equipment.

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 an 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).

Rainwater harvesting by solar power panels

Good quality water resources near populated areas are becoming scarce and costly for consumers. In addition to solar and wind energy, rainwater is a major renewable resource for any land. Vast areas are being covered by solar PV panels every year in all parts of the world. Solar panels can also be used for harvesting most of the rainwater falling on them and drinking quality water, free from bacteria and suspended matter, can be generated by simple filtration and disinfection processes as rainwater is very low in salinity. [19] [20] [21] Exploiting rainwater for value-added products like bottled drinking water makes solar PV power plants profitable even in high rainfall or cloudy areas by generating additional income. Recently, cost-effective rainwater collection in existing wells has been found highly effective in raising groundwater levels in India.

Other innovations

The Groasis Waterboxx is an example of low scale technology, in this case to assist planting of trees in arid area. It harvests rainwater and dew.

Advantages

Rainwater harvesting provides the independent water supply during regional water restrictions, and in developed countries, it is often used to supplement the main supply. It provides water when a drought occurs, can help mitigate flooding of low-lying areas, and reduces demand on wells which may enable groundwater levels to be sustained. Rainwater harvesting increases the availability of water during dry seasons by increasing the levels of dried borewells and wells. Surface water supply is readily available for various purposes thus reducing dependence on underground water. It improves the quality of ground by diluting salinity. It does not cause pollution and is environmentally friendly. It is cost-effective and easily affordable. It also helps in the availability of potable water, as rainwater is substantially free of salinity and other salts. Applications of rainwater harvesting in urban water system provides a substantial benefit for both water supply and wastewater subsystems by reducing the need for clean water in water distribution systems, less generated stormwater in sewer systems, [22] and a reduction in stormwater runoff polluting freshwater bodies.

A large body of work has focused on the development of life cycle assessment and its costing methodologies to assess the level of environmental impacts and money that can be saved by implementing rainwater harvesting systems. [21]

Independent water supply

Rainwater harvesting provides an independent water supply during water restrictions. In areas where clean water is costly, or difficult to come by, rainwater harvesting is a critical source of clean water. In developed countries, rainwater is often harvested to be used as a supplemental source of water rather than the main source, but the harvesting of rainwater can also decrease a household's water costs or overall usage levels. Rainwater is safe to drink if the consumers do additional treatments before drinking. Boiling water helps to kill germs. Adding another supplement to the system such as a first flush diverter is also a common procedure to avoid contaminants of the water. [23]

Supplemental in drought

When drought occurs, rainwater harvested in past months can be used. If rain is scarce but also unpredictable, the use of a rainwater harvesting system can be critical to capturing the rain when it does fall. Many countries with arid environments, use rainwater harvesting as a cheap and reliable source of clean water. To enhance irrigation in arid environments, ridges of soil are constructed to trap and prevent rainwater from running downhills. Even in periods of low rainfall, enough water is collected for crops to grow. Water can be collected from roofs and tanks can be constructed to hold large quantities of rainwater.

In addition, rainwater harvesting decreases the demand for water from wells, enabling groundwater levels to be further sustained rather than depleted.

Life-cycle assessment

Life-cycle assessment is a methodology used to evaluate the environmental impacts of a system from cradle-to-grave of its lifetime. Devkota et al, [24] [25] developed such a methodology for rainwater harvesting, and found that the building design (e.g., dimensions) and function (e.g., educational, residential, etc.) play critical roles in the environmental performance of the system.

To address the functional parameters of rainwater harvesting systems, a new metric was developed – the demand to supply ratio (D/S) – identifying the ideal building design (supply) and function (demand) in regard to the environmental performance of rainwater harvesting for toilet flushing. With the idea that supply of rainwater not only saves the potable water but also saves the stormwater entering the combined sewer network (thereby requiring treatment), the savings in environmental emissions were higher if the buildings are connected to a combined sewer network compared to separate one. [25]

Cost-effectiveness

Although standard RWH systems can provide a water source to developing regions facing poverty, the average cost for an RWH setup can be costly depending on the type of technology used. Governmental aid and NGOs can assist communities facing poverty by providing the materials and education necessary to develop and maintain RWH setups. [26]

Some studies show that rainwater harvesting is a widely applicable solution for water scarcity and other multiple usages, owing to its cost-effectiveness and eco-friendliness. [26] [27] Constructing new substantial, centralized water supply systems, such as dams, is prone to damage local ecosystems, generates external social costs, and has limited usages, especially in developing countries or impoverished communities. On the other hand, installing rainwater harvesting systems is verified by a number of studies to provide local communities a sustainable water source, accompanied by other various benefits, including protection from flood and control of water runoff, even in poor regions. [26] [28] Rainwater harvesting systems that do not require major construction or periodic maintenance by a professional from outside the community are more friendly to the environment and more likely to benefit the local people for a longer period of time. [26] Thus, rainwater harvesting systems that could be installed and maintained by local people have bigger chances to be accepted and used by more people.

The usage of in-situ technologies can reduce investment costs in rainwater harvesting. In-situ technologies for rainwater harvesting could be a feasible option for rural areas since less material is required to construct them. They can provide a reliable water source that can be utilized to expand agricultural outputs. Above-ground tanks can collect water for domestic use; however, such units can be unaffordable to people in poverty. [29]

Limitations

Rainwater harvesting is a widely used method of storing rainwater in countries presenting with drought characteristics. Several pieces of research have derived and developed different criteria and techniques to select suitable sites for harvesting rainwater. Some research was identified and selected suitable sites for the potential erection of dams, as well as derived a model builder in ArcMap 10.4.1. The model combined several parameters, such as slope, runoff potential, land cover/use, stream order, soil quality, and hydrology to determine the suitability of the site for harvesting rainwater. [30]

Harvested water from RWH systems can be minimal during below-average precipitation in arid urban regions such as the Middle East. RWH is useful for developing areas as it collects water for irrigation and domestic purposes. However, the gathered water should be adequately filtered to ensure safe drinking. [31]

Quality of water

Rainwater may need to be analyzed properly, and used in a way appropriate to its safety. In the Gansu province, for example, solar water disinfection is used by boiling harvested rainwater in parabolic solar cookers before being used for drinking. [32] These so-called "appropriate technology" methods provide low-cost disinfection options for treatment of stored rainwater for drinking.

While rainwater itself is a clean source of water, often better than groundwater or water from rivers or lakes, [33] the process of collection and storage often leaves the water polluted and non-potable. Rainwater harvested from roofs can contain human, animal and bird feces, mosses and lichens, windblown dust, particulates from urban pollution, pesticides, and inorganic ions from the sea (Ca, Mg, Na, K, Cl, SO4), and dissolved gases (CO2, NOx, SOx). High levels of pesticide have been found in rainwater in Europe with the highest concentrations occurring in the first rain immediately after a dry spell; [34] the concentration of these and other contaminants are reduced significantly by diverting the initial flow of run-off water to waste. Improved water quality can also be obtained by using a floating draw-off mechanism (rather than from the base of the tank) and by using a series of tanks, withdraw from the last in series. Prefiltration is a common practice used in the industry to keep the system healthy and ensure that the water entering the tank is free of large sediments.

A concept of rainwater harvesting and cleaning it with solar energy for rural household drinking purposes has been developed by Nimbkar Agricultural Research Institute. [35]

Conceptually, a water supply system should match the quality of water with the end-user. However, in most of the developed world, high-quality potable water is used for all end uses. This approach wastes money and energy and imposes unnecessary impacts on the environment. Supplying rainwater that has gone through preliminary filtration measures for non-potable water uses, such as toilet flushing, irrigation, and laundry, may be a significant part of a sustainable water management strategy.

Rainwater cisterns can also act as habitat for pathogen-bearing mosquitoes. As a result, care must be taken to ensure that female mosquitoes can not access the cistern to lay eggs. Larvae eating fish can also be added to the cistern, or it can be chemically treated.

Country examples

Canada

This section is an excerpt from Rainwater harvesting in Canada.[ edit ]
A small rainwater harvesting tank in Quebec. Maison solaire ecoologique, ile Sainte-Helene 12.JPG
A small rainwater harvesting tank in Quebec.

Rainwater harvesting is becoming a procedure that many Canadians are incorporating into their daily lives, although data does not give exact figures for implementation. [36] Rainwater can be used for a number of purposes including stormwater reduction, irrigation, laundry and portable toilets. [37] In addition to low costs, rainwater harvesting is useful for landscape irrigation. Many Canadians have started implementing rainwater harvesting systems for use in stormwater reduction, irrigation, laundry, and lavatory plumbing. Provincial and municipal legislation is in place for regulating the rights and uses for captured rainwater. Substantial reform to Canadian law since the mid-2000s has increased the use of this technology in agricultural, industrial, and residential use, but ambiguity remains amongst legislation in many provinces. Bylaws and local municipal codes often regulate rainwater harvesting.

Multiple organizations and companies have developed in Canada to provide education, technology, and installation for rainwater harvesting. These include the Canadian Association for Rainwater Management (CANARM), [38] Canadian Mortgage and Housing Corporation (CMHC), and CleanFlo Water Technologies. [39] CANARM is an association that prioritizes education, training and spreading awareness for those entering the rainwater harvesting industry. [38]

India

This section is an excerpt from Water supply and sanitation in India § Rainwater harvesting.[ edit ]
In the early 21st century, India began heavily investing in rainwater harvesting infrastructure and policy as an urgent response to water scarcity. [40] In 2001, Tamil Nadu became the first Indian state to make rainwater harvesting compulsory in every building to avoid groundwater depletion. In Rajasthan, rainwater harvesting has traditionally been practiced by the people of the Thar Desert. Increase in rainwater harvesting efforts across the nation have revived ancient water harvesting systems in Rajasthan, such as the chauka system from the Jaipur district. Other large cities like Pune, Mumbai and Bangalore all have varying rules for mandatory rainwater harvesting, especially in new buildings. In 2002, the Municipal Corporation of Greater Mumbai required all new buildings over 1000 square meters to have rainwater harvesting infrastructure. [41] The law was expanded in 2007 to 300 square meters. The goal was to ensure buildings had enough water to last them through non-monsoon seasons. The process included a catchment system, an initial flush, and extensive filtering. As of 2021, the Brihanmumbai Municipal Corporation (BMC) reported 3000 newly constructed or redeveloped buildings with rainwater harvesting infrastructure. [42] However, many residents have complained that the stored water is contaminated, turning saline and brackish. Experts and residents argue that BMC authorities have done little to take implementation seriously, and the actual effectiveness of the rainwater harvesting mandate is unknown. [43]

While rainwater harvesting in an urban context has gained traction in recent years, evidence points toward rainwater harvesting in rural India since ancient times.

United Kingdom

This section is an excerpt from Rainwater harvesting in the United Kingdom.[ edit ]

Rainwater harvesting in the United Kingdom is a practice of growing importance. Rainwater harvesting in the UK is both a traditional and a reviving technique for collecting water for domestic uses. The water is generally used for non-hygienic purposes like watering gardens, flushing toilets, and washing clothes. [44] In commercial premises like supermarkets it is used for things like toilet flushing where larger tank systems can be used collecting between 1000 and 7500 litres of water. It is claimed that in the South East of England there is less water available per person than in many Mediterranean countries.[ citation needed ]

Rainwater is almost always collected strictly from the roof, then heavily filtered using either a filter attached to the down pipe, a fine basket filter or for more expensive systems like self-cleaning filters placed in an underground tank. [45] UK homes using some form of rainwater harvesting system can reduce their mains water usage by 50% or more, although a 20%–30% saving is more common. [46] At present (depending on the area in the UK) mains water delivery and equivalent waste water and sewerage processing costs about £2 per cubic metre. Reducing mains-water metered volumes also reduces the sewerage and sewage disposal costs in the same proportion, because water company billing assumes that all water taken into the house is discharged into the sewers.

United States

This section is an excerpt from Water supply and sanitation in the United States § Rainwater harvesting.[ edit ]
In the United States, until 2009 in Colorado, water rights laws almost completely restricted rainwater harvesting; a property owner who captured rainwater was deemed to be stealing it from those who have the rights to take water from the watershed. Now, residential good owners who meet certain criteria may obtain a permit to install a rooftop precipitation collection system (SB 09-080). [47] Up to 10 large scale pilot studies may also be permitted (HB 09–1129). [48] The main factor in persuading the Colorado Legislature to change the law was a 2007 study that found that in an average year, 97% of the precipitation that fell in Douglas County, in the southern suburbs of Denver, never reached a stream—it was used by plants or evaporated on the ground. Rainwater catchment is mandatory for new dwellings in Santa Fe, New Mexico. [49] Texas offers a sales tax exemption on the purchase of rainwater harvesting equipment. Both Texas [50] and Ohio allow the practice even for potable purposes. Oklahoma passed the Water for 2060 Act in 2012, to promote pilot projects for rainwater and graywater use among other water-saving techniques. [51]

Other countries

Rainwater harvesting tank in Rwanda. Rainwater harvesting tank (5981896147).jpg
Rainwater harvesting tank in Rwanda.

History

The construction and use of cisterns to store rainwater can be traced back to the Neolithic Age, when waterproof lime plaster cisterns were built in the floors of houses in village locations of the Levant, a large area in Southwest Asia, south of the Taurus Mountains, bounded by the Mediterranean Sea in the west, the Arabian Desert in the south, and Mesopotamia in the east. By the late 4000 BC[ clarification needed ], cisterns were essential elements of emerging water management techniques used in dry-land farming. [58]

Many ancient cisterns have been discovered in some parts of Jerusalem and throughout what is today Israel/Palestine. At the site believed by some to be that of the biblical city of Ai (Khirbet et-Tell), a large cistern dating back to around 2500 BC was discovered that had a capacity of nearly 1,700 m3 (60,000 cu ft). It was carved out of a solid rock, lined with large stones, and sealed with clay to keep it from leaking. [58]

The Greek island of Crete is also known for its use of large cisterns for rainwater collection and storage during the Minoan period from 2,600 BC–1,100 BC. Four large cisterns have been discovered at Myrtos-Pyrgos, Archanes, and Zakroeach. The cistern found at Myrtos-Pyrgos was found to have a capacity of more than 80 m3 (2,800 cu ft) and to date back to 1700 BC. [58]

Around 300 BC, farming communities in Balochistan (now located in Pakistan, Afghanistan, and Iran), and Kutch, India, used rainwater harvesting for agriculture and many other uses. [59] Rainwater harvesting was done by Chola kings as well. [60] Rainwater from the Brihadeeswarar temple (located in Balaganapathy Nagar, Thanjavur, India) was collected in Shivaganga tank. [61] During the later Chola period, the Vīrānam tank was built (1011 to 1037 AD) 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. [62] While Roman aqueducts are well-known, Roman cisterns were also commonly used and their construction expanded with the Empire. [58] For example, in Pompeii, rooftop water storage was common before the construction of the aqueduct in the 1st century BC. [63] This history continued with the Byzantine Empire; for example, the Basilica Cistern in Istanbul.

Though little known, the town of Venice for centuries depended on rainwater harvesting. The lagoon surrounding Venice is brackish water, which is unsuitable for drinking. Venice's ancient inhabitants established a rainwater collection system based on man-made insulated collection wells. [64] 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. Still, the wells remained in use and were especially important in times of war when an enemy could block access to the mainland water.

See also

Related Research Articles

<span class="mw-page-title-main">Stormwater</span> Water that originates during precipitation events and snow/ice melt

Stormwater, also written storm water, is water that originates from precipitation (storm), including heavy rain and meltwater from hail and snow. Stormwater can soak into the soil (infiltrate) and become groundwater, be stored on depressed land surface in ponds and puddles, evaporate back into the atmosphere, or contribute to surface runoff. Most runoff is conveyed directly as surface water to nearby streams, rivers or other large water bodies without treatment.

<span class="mw-page-title-main">Greywater</span> Type of wastewater generated in households without toilet wastewater

Greywater refers to domestic wastewater generated in households or office buildings from streams without fecal contamination, i.e., all streams except for the wastewater from toilets. Sources of greywater include sinks, showers, baths, washing machines or dishwashers. As greywater contains fewer pathogens than blackwater, it is generally safer to handle and easier to treat and reuse onsite for toilet flushing, landscape or crop irrigation, and other non-potable uses. Greywater may still have some pathogen content from laundering soiled clothing or cleaning the anal area in the shower or bath.

<span class="mw-page-title-main">Water conservation</span> Policies for sustainable development of water use

Water conservation aims to sustainably manage the natural resource of fresh water, protect the hydrosphere, and meet current and future human demand. Water conservation makes it possible to avoid water scarcity. It covers all the policies, strategies and activities to reach these aims. Population, household size and growth and affluence all affect how much water is used.

A blue roof is a roof of a building that is designed explicitly to provide initial temporary water storage and then gradual release of stored water, typically rainfall. Blue roofs are constructed on flat or low sloped roofs in urban communities where flooding is a risk due to a lack of permeable surfaces for water to infiltrate, or seep back into the ground.

<span class="mw-page-title-main">Cistern</span> Waterproof receptacle for holding liquids, usually water

A cistern is a waterproof receptacle for holding liquids, usually water. Cisterns are often built to catch and store rainwater. To prevent leakage, the interior of the cistern is often lined with hydraulic plaster.

<span class="mw-page-title-main">Combined sewer</span> Sewage collection system of pipes and tunnels designed to also collect surface runoff

A combined sewer is a type of gravity sewer with a system of pipes, tunnels, pump stations etc. to transport sewage and urban runoff together to a sewage treatment plant or disposal site. This means that during rain events, the sewage gets diluted, resulting in higher flowrates at the treatment site. Uncontaminated stormwater simply dilutes sewage, but runoff may dissolve or suspend virtually anything it contacts on roofs, streets, and storage yards. As rainfall travels over roofs and the ground, it may pick up various contaminants including soil particles and other sediment, heavy metals, organic compounds, animal waste, and oil and grease. Combined sewers may also receive dry weather drainage from landscape irrigation, construction dewatering, and washing buildings and sidewalks.

The United States Environmental Protection Agency (EPA) Storm Water Management Model (SWMM) is a dynamic rainfall–runoff–subsurface runoff simulation model used for single-event to long-term (continuous) simulation of the surface/subsurface hydrology quantity and quality from primarily urban/suburban areas.

<span class="mw-page-title-main">Rain garden</span> Runoff reducing landscaping method

Rain gardens, also called bioretention facilities, are one of a variety of practices designed to increase rain runoff reabsorption by the soil. They can also be used to treat polluted stormwater runoff. Rain gardens are designed landscape sites that reduce the flow rate, total quantity, and pollutant load of runoff from impervious urban areas like roofs, driveways, walkways, parking lots, and compacted lawn areas. Rain gardens rely on plants and natural or engineered soil medium to retain stormwater and increase the lag time of infiltration, while remediating and filtering pollutants carried by urban runoff. Rain gardens provide a method to reuse and optimize any rain that falls, reducing or avoiding the need for additional irrigation. A benefit of planting rain gardens is the consequential decrease in ambient air and water temperature, a mitigation that is especially effective in urban areas containing an abundance of impervious surfaces that absorb heat in a phenomenon known as the heat-island effect.

<span class="mw-page-title-main">First flush</span> Initial surface runoff of a rainstorm

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<span class="mw-page-title-main">Sustainable drainage system</span> Designed to reduce the potential impact of development

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<span class="mw-page-title-main">Rainwater tank</span>

A rainwater tank is a water tank used to collect and store rain water runoff, typically from rooftops via pipes. Rainwater tanks are devices for collecting and maintaining harvested rain. A rainwater catchment or collection system can yield 1,000 litres (260 US gal) of water from 1 cm (0.4 in) of rain on a 100 m2 (1,100 sq ft) roof.

<span class="mw-page-title-main">Urban runoff</span> Surface runoff of water caused by urbanization

Urban runoff is surface runoff of rainwater, landscape irrigation, and car washing created by urbanization. Impervious surfaces are constructed during land development. During rain, storms, and other precipitation events, these surfaces, along with rooftops, carry polluted stormwater to storm drains, instead of allowing the water to percolate through soil. This causes lowering of the water table and flooding since the amount of water that remains on the surface is greater. Most municipal storm sewer systems discharge untreated stormwater to streams, rivers, and bays. This excess water can also make its way into people's properties through basement backups and seepage through building wall and floors.

Aquifer storage and recovery (ASR) is the direct injection of surface water supplies such as potable water, reclaimed water, or river water into an aquifer for later recovery and use. The injection and extraction is often done by means of a well. In areas where the rainwater cannot percolate the soil or where it is not capable of percolating it fast enough and where the rainwater is thus diverted to rivers, rainwater ASR could help to keep the rainwater within an area. ASR is used for municipal, industrial and agricultural purposes.

<span class="mw-page-title-main">Stormwater harvesting</span>

Stormwater harvesting or stormwater reuse is the collection, accumulation, treatment or purification, and storage of stormwater for its eventual reuse. While rainwater harvesting collects precipitation primarily from rooftops, stormwater harvesting deals with collection of runoff from creeks, gullies, ephemeral streams and underground conveyance. It can also include catchment areas from developed surfaces, such as roads or parking lots, or other urban environments such as parks, gardens and playing fields.

<span class="mw-page-title-main">Water-sensitive urban design</span> Integrated approach to urban water cycle

Water-sensitive urban design (WSUD) is a land planning and engineering design approach which integrates the urban water cycle, including stormwater, groundwater, and wastewater management and water supply, into urban design to minimise environmental degradation and improve aesthetic and recreational appeal. WSUD is a term used in the Middle East and Australia and is similar to low-impact development (LID), a term used in the United States; and Sustainable Drainage System (SuDS), a term used in the United Kingdom.

<span class="mw-page-title-main">Water storage</span> Storage of water by various means

Water storage is a broad term referring to storage of both potable water for consumption, and non potable water for use in agriculture. In both developing countries and some developed countries found in tropical climates, there is a need to store potable drinking water during the dry season. In agriculture water storage, water is stored for later use in natural water sources, such as groundwater aquifers, soil water, natural wetlands, and small artificial ponds, tanks and reservoirs behind major dams. Storing water invites a host of potential issues regardless of that water's intended purpose, including contamination through organic and inorganic means.

Rainwater harvesting in the United Kingdom is a practice of growing importance. Rainwater harvesting in the UK is both a traditional and a reviving technique for collecting water for domestic uses. The water is generally used for non-hygienic purposes like watering gardens, flushing toilets, and washing clothes. In commercial premises like supermarkets it is used for things like toilet flushing where larger tank systems can be used collecting between 1000 and 7500 litres of water. It is claimed that in the South East of England there is less water available per person than in many Mediterranean countries.

<span class="mw-page-title-main">Low-impact development (U.S. and Canada)</span>

Low-impact development (LID) is a term used in Canada and the United States to describe a land planning and engineering design approach to manage stormwater runoff as part of green infrastructure. LID emphasizes conservation and use of on-site natural features to protect water quality. This approach implements engineered small-scale hydrologic controls to replicate the pre-development hydrologic regime of watersheds through infiltrating, filtering, storing, evaporating, and detaining runoff close to its source. Green infrastructure investments are one approach that often yields multiple benefits and builds city resilience.

<span class="mw-page-title-main">Rainwater harvesting in Canada</span>

Rainwater harvesting is becoming a procedure that many Canadians are incorporating into their daily lives, although data does not give exact figures for implementation. Rainwater can be used for a number of purposes including stormwater reduction, irrigation, laundry and portable toilets. In addition to low costs, rainwater harvesting is useful for landscape irrigation. Many Canadians have started implementing rainwater harvesting systems for use in stormwater reduction, irrigation, laundry, and lavatory plumbing. Provincial and municipal legislation is in place for regulating the rights and uses for captured rainwater. Substantial reform to Canadian law since the mid-2000s has increased the use of this technology in agricultural, industrial, and residential use, but ambiguity remains amongst legislation in many provinces. Bylaws and local municipal codes often regulate rainwater harvesting.

Rainwater management is a series of countermeasures to reduce runoff volume and improve water quality by replicating the natural hydrology and water balance of a site, with consideration of rainwater harvesting, urban flood management and rainwater runoff pollution control.

References

  1. 1 2 Staddon, Chad; Rogers, Josh; Warriner, Calum; Ward, Sarah; Powell, Wayne (2018-11-17). "Why doesn't every family practice rainwater harvesting? Factors that affect the decision to adopt rainwater harvesting as a household water security strategy in central Uganda". Water International. 43 (8): 1114–1135. Bibcode:2018WatIn..43.1114S. doi: 10.1080/02508060.2018.1535417 . ISSN   0250-8060. S2CID   158857347.
  2. ↑ Managing Urban Stormwater: Harvesting and reuse (PDF) (Report). Sydney, Australia: New South Wales Department of Environment and Conservation. 1 April 2006. ISBN   1-74137-875-3. Archived from the original (PDF) on 2020-07-16.
  3. ↑ "Rainwater Harvesting for Livestock". www.ntotank.com. Archived from the original on 2018-11-21. Retrieved 2018-11-21.
  4. ↑ Kinkade-Levario, Heather (2007). Design for Water : Rainwater Harvesting, Stormwater Catchment, and Alternate Water Reuse. Gabriola Island, B.C.: New Society Publishers. p. 27. ISBN   978-0-86571-580-6.
  5. ↑ Bagel, Ravi; Stepan, Lea; Hill, Joseph K.W. (2017). Water, knowledge and the environment in Asia : epistemologies, practices and locales. London. ISBN   9781315543161.{{cite book}}: CS1 maint: location missing publisher (link)
  6. ↑ Rural Water Supply Network. "Rural Water Supply Network Self-supply site". www.rural-water-supply.net/en/self-supply. Archived from the original on 2019-01-14. Retrieved 2017-03-19.
  7. ↑ it:Architettura eoliana
  8. ↑ commons:Category:Rainwater harvesting in Nepal
  9. ↑ "Understanding the Kenya 2016 Water Act" (PDF). 2030wrg. Archived (PDF) from the original on July 26, 2021. Retrieved July 26, 2021.
  10. 1 2 Amos, Caleb Christian; Rahman, Ataur; Karim, Fazlul; Gathenya, John Mwangi (November 2018). "A scoping review of roof harvested rainwater usage in urban agriculture: Australia and Kenya in focus". Journal of Cleaner Production. 202: 174–190. Bibcode:2018JCPro.202..174A. doi:10.1016/j.jclepro.2018.08.108. ISSN   0959-6526. S2CID   158718294.
  11. ↑ Fletcher-Paul, Dr. Lystra. "Feasibility Study of Rainwater Harvesting for Agriculture in the Caribbean Subregion" (PDF). FAO. Archived (PDF) from the original on 2018-04-25. Retrieved 2018-04-25.
  12. ↑ Zhu, Qiang; et al. (2015). Rainwater Harvesting for Agriculture and Water Supply. Beijing: Springer. p. 20. ISBN   978-981-287-964-6.
  13. ↑ "Rainwater harvesting". Archived from the original on 2019-05-08. Retrieved 2016-03-03.
  14. ↑ "Rainwater harvesting in Germany". www.rainwaterharvesting.org. Archived from the original on 2019-02-19. Retrieved 2018-04-24.
  15. ↑ "Learning legacy: Lessons learned from the London 2012 Games construction project" (PDF). Olympic Delivery Authority. 2011. Archived (PDF) from the original on 2015-12-08. Retrieved 2018-04-24.
  16. ↑ "Rainwater Harvesting - Controls in the Cloud". M. C. 2013-10-03. Archived from the original on 2019-08-05. Retrieved 11 January 2015.
  17. ↑ O'Brien, Sara Ashley (2014-11-11). "The Tech Behind Smart Cities - Eliminating Water Pollution". CNN Money. Archived from the original on 2014-11-14. Retrieved 13 November 2014.
  18. ↑ Braga, Andrea. "Making Green Work, and Work Harder" (PDF). Geosyntec. p. 5. Archived from the original (PDF) on 4 March 2016. Retrieved 30 November 2014.
  19. ↑ "Rain fed solar-powered water purification systems". Archived from the original on 21 October 2017. Retrieved 21 October 2017.
  20. ↑ "Inverted Umbrella Brings Clean Water & Clean Power To India". 2017-12-04. Archived from the original on 2018-07-09. Retrieved 5 December 2017.
  21. 1 2 "New rooftop solar hydro panels harvest drinking water and energy at the same time". 29 November 2017. Archived from the original on 2019-08-10. Retrieved 2017-11-30.
  22. ↑ Behzadian, k; Kapelan, Z (2015). "Advantages of integrated and sustainability based assessment for metabolism-based strategic planning of urban water systems" (PDF). Science of the Total Environment. 527–528: 220–231. Bibcode:2015ScTEn.527..220B. doi:10.1016/j.scitotenv.2015.04.097. hdl: 10871/17351 . PMID   25965035.
  23. ↑ Centers of Disease Control and Prevention (CDC), 2013 Retrieved from https://www.cdc.gov/healthywater/drinking/private/rainwater-collection.html Archived 2020-04-06 at the Wayback Machine
  24. ↑ Devkota, J.; Schlachter, H.; Anand, C.; Phillips, R.; Apul, Defne (November 2013). "Development and application of EEAST: A lifecycle-based model for use of harvested rainwater and composting toilets in buildings". Journal of Environmental Management. 130: 397–404. Bibcode:2013JEnvM.130..397D. doi:10.1016/j.jenvman.2013.09.015. PMID   24141064.
  25. 1 2 Devkota, Jay; Schlachter, Hannah; Apul, Defne (May 2015). "Life cycle based evaluation of harvested rainwater use in toilets and for irrigation". Journal of Cleaner Production. 95: 311–321. Bibcode:2015JCPro..95..311D. doi:10.1016/j.jclepro.2015.02.021.
  26. 1 2 3 4 Cain, Nicholas L. (2014). "A Different Path: The Global Water Crisis and Rainwater Harvesting". Consilience (12): 147–157. ISSN   1948-3074. JSTOR   26476158. Archived from the original on 2021-08-10. Retrieved 2020-11-26.
  27. ↑ Staddon, Chad; Rogers, Josh; Warriner, Calum; Ward, Sarah; Powell, Wayne (17 November 2018). "Why doesn't every family practice rainwater harvesting? Factors that affect the decision to adopt rainwater harvesting as a household water security strategy in central Uganda". Water International. 43 (8): 1114–1135. Bibcode:2018WatIn..43.1114S. doi: 10.1080/02508060.2018.1535417 . S2CID   158857347.
  28. ↑ Furumai, Hiroaki (2008). Recent application of rainwater storage and harvesting in Japan.
  29. ↑ Lunduka, Rodney (2011). "ECONOMIC ANALYSIS OF RAINWATER HARVESTING AND SMALL-SCALE WATER RESOURCES DEVELOPMENT". ResearchGate. Retrieved 2020-11-25.
  30. ↑ Ibrahim, Gaylan Rasul Faqe; Rasul, Azad; Ali Hamid, Arieann; Ali, Zana Fattah; Dewana, Amanj Ahmad (April 2019). "Suitable Site Selection for Rainwater Harvesting and Storage Case Study Using Dohuk Governorate". Water. 11 (4): 864. doi: 10.3390/w11040864 . CC-BY icon.svg Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License Archived 2017-10-16 at the Wayback Machine .
  31. ↑ Lange, J.; Husary, S.; Gunkel, A.; Bastian, D.; Grodek, T. (2012-03-06). "Potentials and limits of urban rainwater harvesting in the Middle East". Hydrology and Earth System Sciences. 16 (3): 715–724. Bibcode:2012HESS...16..715L. doi: 10.5194/hess-16-715-2012 . ISSN   1607-7938. Archived from the original on 2022-07-10. Retrieved 2020-11-28.
  32. ↑ Chen, Xuefei (27 August 2007). "Rainwater harvesting benefits farmers in Gansu". People's Daily Online. Archived from the original on 20 October 2012. Retrieved 10 July 2018.
  33. ↑ Hatch, Jacob. "The Many Benefits of Rainwater Harvesting". Hydration Anywhere. Archived from the original on 13 December 2016. Retrieved 3 August 2018.
  34. ↑ Pearce, Fred; Mackenzie, Debora (3 April 1999). "It's raining pesticides". New Scientist. No. 2180. Archived from the original on 10 July 2018. Retrieved 10 July 2018.
  35. ↑ "Low cost drinking water technology – rainwater harvesting with solar purification. Current Science, Vol. 118, No.6, 25 March 2020" (PDF). Archived (PDF) from the original on 19 January 2022. Retrieved 27 March 2020.
  36. ↑ Collecting and Using Rainwater at Home. Canadian Housing and Mortgage Corporation. 2013.
  37. ↑ Duke, Katie (2014). "Ownership of Rainwater and the Legality of Rainwater Harvesting in British Columbia". Appeal. Retrieved 2016-03-29.
  38. 1 2 "CANARM.org - Canadian Association for Rainwater Management". www.canarm.org. Retrieved 2016-03-22.
  39. ↑ "Homepage - Water, Septic Tanks and Rainwater Harvesting Systems Canada - Clean-Flo Rainwater Management". Water, Septic Tanks and Rainwater Harvesting Systems Canada - Clean-Flo Rainwater Management. Retrieved 2016-03-22.
  40. ↑ Kumar, M. Dinesh; Ghosh, Shantanu; Patel, Ankit; Singh, Om Prakash; Ravindranath, R.; Kumar, M. Dinesh; Ghosh, Shantanu; Patel, Ankit; Singh, Om Prakash; Ravindranath, R. (2006). Kumar, M. Dinesh; Ghosh, Shantanu; Patel, Ankit; Singh, Om Prakash; Ravindranath, R. (eds.). "Rainwater harvesting in India: some critical issues for basin planning and research". Land Use and Water Resources Research. doi:10.22004/ag.econ.47964.
  41. ↑ Button, Cat (4 May 2017). "Domesticating water supplies through rainwater harvesting in Mumbai". Gender & Development. 25 (2): 269–282. doi:10.1080/13552074.2017.1339949. ISSN   1355-2074. S2CID   80471348.
  42. ↑ "India Rainwater Harvesting Market, By Type (Rain Barrel System, Dry System, Wet System, Green Roof System), By Harvesting Method (Above Ground {Ground Surface and Storage Tank}, Under Ground), By Application (Residential, Commercial, Industrial and Agricultural), By Region, By Competition Forecast & Opportunities, 2018–2028". TechSci Research.
  43. ↑ Johari, Aarefa (17 July 2019). "Mumbai could save water through its mandatory rainwater harvesting rule – but no one seems to care". Scroll.in. Retrieved 12 May 2023.
  44. ↑ "Harvesting rainwater for domestic uses: an information guide" (PDF). Environment Agency. October 2010. Retrieved 2021-01-23.
  45. ↑ "Rainwater Filters". Rainharvesting Systems. Retrieved 2017-03-08.
  46. ↑ "Rainwater harvesting". SVCwater. Retrieved 2013-07-27.
  47. ↑ "Rainwater Collection in Colorado" (PDF). Colorado water law, notices. Colorado Division of Water Resources. Archived from the original (PDF) on March 6, 2016. Retrieved March 24, 2012.
  48. ↑ "Criteria and Guidelines for the "Rainwater Harvesting"" (PDF). Pilot Project Program. Colorado Water Conservation Board (CWCB). January 28, 2010. Archived from the original (PDF) on March 5, 2016. Retrieved March 24, 2012.
  49. ↑ Johnson, Kirk (June 28, 2009). "It's Now Legal to Catch a Raindrop in Colorado". The New York Times . Retrieved June 30, 2009.
  50. ↑ "82(R) H.B. No. 3391. An act relating to rainwater harvesting and other water conservation initiatives. † went into effect on September 1, 2011". 82nd Regular Session. Texas Legislature Online. Retrieved February 8, 2013.
  51. ↑ "State Rainwater Harvesting Statutes, Programs and Legislation". NCSL. Archived from the original on October 8, 2013. Retrieved February 7, 2013.
  52. ↑ JMP (2016). "Joint Monitoring Programme Thailand Data" . Retrieved 2017-03-13.[ permanent dead link ]
  53. ↑ Saladin, Matthias (2016). "Rainwater Harvesting in Thailand - learning from the World Champions". Archived from the original on 2019-01-29. Retrieved 2017-03-13.
  54. ↑ Harry Low (December 23, 2016). "Why houses in Bermuda have white stepped roofs". BBC News. Archived from the original on 2016-12-23. Retrieved 2016-12-23.
  55. ↑ "Rainwater tanks". Greater Wellington Regional Council. 28 April 2016. Archived from the original on 14 April 2016. Retrieved 21 March 2017.
  56. ↑ "Parliament Of The Democratic Socialist Republic of Sri Lanka" (PDF). Archived from the original (PDF) on 2013-11-04. Retrieved 2011-12-09.
  57. ↑ "Lanka Rain Water Harvesting Forum (LRWHF)". Archived from the original on 2015-02-03. Retrieved 2011-12-09.
  58. 1 2 3 4 Mays, Larry; Antoniou, George & Angelakis, Andreas (2013). "History of water cisterns: Legacies and lessons". Water. 5 (4): 1916–1940. doi: 10.3390/w5041916 . hdl: 2286/R.I.43114 .
  59. ↑ "Rain water Harvesting". Tamil Nadu State Government, India. Archived from the original on 12 August 2019. Retrieved 23 January 2012.
  60. ↑ "Believes in past, lives in future". The Hindu . India. 17 July 2010. Archived from the original on 9 October 2012.
  61. ↑ "Rare Chola inscription found near Big Temple". The Hindu . India. 24 August 2003. Archived from the original on 22 November 2003.
  62. ↑ Kamash, Zena (2010). Archaeologies of Water in the Roman Near East. Gorgias Press.
  63. ↑ "Water Supply Systems: Cisterns, Reservoirs, Aqueducts | Roman Building Technology and Architecture, University of California Santa Barbara". ArchServe. Archived from the original on 2016-07-18. Retrieved 2018-04-13.
  64. ↑ "Venetian wells". Archived from the original on 2019-05-09. Retrieved 2016-08-29.
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