What is a rainwater harvesting system?

MK. PENGELOLAAN SDALH

TEKNOLOGI

PANEN AIR HUJAN

&

PEMANFAATANNYA

diabstraksikan oleh: smno, psdl.pdkl.ppsub2013

PANEN AIR HUJAN

Rainwater harvesting is the accumulation and storage of rainwater for reuse before it reaches the aquifer.

Uses include water for garden, water for livestock, water for irrigation, etc. In many places the water collected is just redirected to a deep pit with percolation.

The harvested water can be used for drinking water as well if the storage is a tank that can be accessed and cleaned when needed.

Rainwater harvesting provides an independent water supply during regional water restrictions, and in developed countries is often used to supplement the mains supply. Rainwater harvesting systems are appealing as they are easy to understand, install and operate. They are effective in 'green droughts' as water is captured from rainfall where runoff is insufficient to flow into dam storages. The quality of captured rainwater is usually sufficient for most household needs, reducing the need for detergents because rainwater is soft. Financial benefits to the users include that rain is 'renewable' at acceptable volumes despite climate change forecasts, and rainwater harvesting systems generally have low running costs, providing water at the point of consumption (Ferguson 2012).

Benefits of widespread rainwater harvesting to the regional reticulated supply system may include reduced treatment, pumping, operation and augmentation costs, reducing peak storm water runoff and storm water processing costs, as well as reduced greenhouse gas emissions due to reduced dependence on pumping and potential augmentation through sources such as desalination (Coombes 2007, White, 2009).

1. Coombes PJ (2007). Energy and economic impacts of rainwater tanks on the operation of regional water systems. Australian Journal of Water

Resources 11 (2) 177 – 191.

2. Ferguson M (2012) a 12-month rainwater tank water savings and energy use study for 52 real life installations. Ozwater12 COnference,

Sydney, Australia: May 2012.

3. White I (2009). Decentralised Environmental Technology Adoption: The household experience with rainwater harvesting. PhD Thesis.

Griffith University.

Diunduh dari: http://en.wikipedia.org/wiki/Rainwater_harvesting ………… 18/1/2013

RAINWATER HARVESTING SYSTEM

Teknologi hijau ini adalah memanen dan mengolah air hujan sehingga kualitasnya sesuai untuk penggunaan lain.

Jumlah Air Hujan

Konfigurasi Atap

Panen Air Hujan Bahan Atap

Sistem

Perlakuan

Diunduh dari: http://waterqualityinsingapore.blogspot.com/2012/05/my-current-green-project-part-2.html …………

18/1/2013

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KUALITAS AIR HUJAN

The concentration of contaminants is reduced significantly by diverting the initial flow of runoff 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, with draw from the last in series. The stored rainwater may need to be analyzed properly before use in a way appropriate to its safety.


Kualitas Air dan Risiko Kesehatan

Rainwater is relatively free from impurities except those picked up by rain from the atmosphere, but the quality of rainwater may deteriorate during harvesting, storage and household use. Wind-blown dirt, leaves, faecal droppings from birds and animals, insects and contaminated litter on the catchment areas can be sources of contamination of rainwater, leading to health risks from the consumption of contaminated water from storage tanks. Poor hygiene in storing water in and abstracting water from tanks or at the point of use can also represent a health concern. However, risks from these hazards can be minimized by good design and practice. Well designed rainwater harvesting systems with clean catchments and storage tanks supported by good hygiene at point of use can offer drinking-water with very low health risk, whereas a poorly designed and managed system can pose high health risks.

Diunduh dari: https://docs.google.com/viewer?a=v&q=cache:GEXXuPgYvpEJ:www.who.int/water_sanitation_health/gdwqrevision/rainwater.pdf+&hl=en&pid

=bl&srcid=ADGEEShSyNPyhojWp-m0eII8ncj63YVUaob62uGVrThNXfz-b6eQjB6YUI-

5AuzOijRNqyZ6n49GCOffBXZp9Ahutj9AFUVaP0Kr6b70P8TaUn8MJqor_o1onUX2Wzte0987I_89imvb&sig=AHIEtbQVuuDWjOa-

31OfDvnjAqyVWhE7Pg ………… 18/1/2013

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PEMASANGAN SISTEM

Rainwater harvesting systems can be installed with minimal skills (White , (2009). The system should be 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. Likewise, the water storage tank should be large enough to contain the captured water.

1.


Griffith University, Australia).

KOMPONEN SISTEM PEMANEN AIR HUJAN

A rainwater harvesting system comprises components of various stages - transporting rainwater through pipes or drains, filtration, and storage in tanks for reuse or recharge. The common components of a rainwater harvesting system involved in these stages are illustrated here.

1. Catchments:

The catchment of a water harvesting system is the surface which directly receives the rainfall and provides water to the system. It can be a paved area like a terrace or courtyard of a building, or an unpaved area like a lawn or open ground. A roof made of reinforced cement concrete (RCC), galvanised iron or corrugated sheets can also be used for water harvesting.

Diunduh dari: http://www.rainwaterharvesting.org/Urban/Components.htm………… 18/1/2013

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2. Coarse mesh at the roof to prevent the passage of debris

3. Gutters:

Channels all around the edge of a sloping roof to collect and transport rainwater to the storage tank.

Gutters can be semi-circular or rectangular and could be made using:

1.

Locally available material such as plain galvanised iron sheet (20 to 22 gauge), folded to required shapes.

2.

Semi-circular gutters of PVC material can be readily prepared by cutting those pipes into two equal semi-circular channels.

3.

Bamboo or betel trunks cut vertically in half.

The size of the gutter should be according to the flow during the highest intensity rain. It is advisable to make them 10 to 15 per cent oversize.

Gutters need to be supported so they do not sag or fall off when loaded with water. The way in which gutters are fixed depends on the construction of the house; it is possible to fix iron or timber brackets into the walls, but for houses having wider eaves, some method of attachment to the rafters is necessary.


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COMPONENTS OF A RAINWATER HARVESTING SYSTEM

4. Conduits

Conduits are pipelines or drains that carry rainwater from the catchment or rooftop area to the harvesting system. Conduits can be of any material like polyvinyl chloride (PVC) or galvanized iron (GI), materials that are commonly available. The following table gives an idea about the diameter of pipe required for draining out rainwater based on rainfall intensity and roof area:

Sizing of rainwater pipe for roof drainage :

Diameter Of pipe

(mm)

50

65

75

100

125

150

50

13.4

24.1

40.8

85.4

-

-

75

8.9

16.0

27.0

57.0

-

mm/ h - millimeters per hour; m - meters

Source: National Building Code

Average rate of rainfall in mm/h

100

6.6

12.0

20.4

42.7

80.5

-

125

5.3

9.6

16.3

34.2

64.3

-

150

4.4

8.0

13.6

28.5

53.5

83.6

200

3.3

6.0

10.2

21.3

40.0

62.7


COMPONENTS OF A RAINWATER HARVESTING SYSTEM

5. First-flushing

A first flush device is a valve that ensures that runoff from the first spell of rain is flushed out and does not enter the system. This needs to be done since the first spell of rain carries a relatively larger amount of pollutants from the air and catchment surface.

Source: A water harvesting manual for urban areas


.

Komponen Sistem Panen Air

Hujan

6. Filter

The filter is used to remove suspended pollutants from rainwater collected over roof. A filter unit is a chamber filled with filtering media such as fibre, coarse sand and gravel layers to remove debris and dirt from water before it enters the storage tank or recharge structure. Charcoal can be added for additional filtration.

1.

Charcoal water filter

A simple charcoal filter can be made in a drum or an earthen pot. The filter is made of gravel, sand and charcoal, all of which are easily available.

2.

Sand filters

Sand filters have commonly available sand as filter media. Sand filters are easy and inexpensive to construct.

These filters can be employed for treatment of water to effectively remove turbidity (suspended particles like silt and clay), colour and microorganisms.

In a simple sand filter that can be constructed domestically, the top layer comprises coarse sand followed by a 5-10 mm layer of gravel followed by

Source:

A water harvesting manual for urban areas

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7. Fasilitas Penyimpanan Air Hujan

There are various options available for the construction of these tanks with respect to the shape, size and the material of construction.

1.

Shape: Cylindrical, rectangular and square.

2.

Material of construction: Reinforced cement concrete, (RCC), ferrocement, masonry, plastic

(polyethylene) or metal (galvanised iron) sheets are commonly used.

3.

Position of tank: Depending on space availability these tanks could be constructed above ground, partly underground or fully underground. Some maintenance measures like cleaning and disinfection are required to ensure the quality of water stored in the container.


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8. Recharge structures

Rainwater may be charged into the groundwater aquifers through any suitable structures like dugwells, borewells, recharge trenches and recharge pits.

Various recharge structures are possible - some which promote the percolation of water through soil strata at shallower depth (e.g., recharge trenches, permeable pavements) whereas others conduct water to greater depths from where it joins the groundwater (e.g. recharge wells). At many locations, existing structures like wells, pits and tanks can be modified as recharge structures, eliminating the need to construct any structures afresh. Here are a few commonly used recharging methods:

1. Recharging of dugwells and abandoned tubewells.

In alluvial and hard rock areas, there are thousands of wells which have either gone dry or whose water levels have declined considerably. These can be recharged directly with rooftop run-off. Rainwater that is collected on the rooftop of the building is diverted by drainpipes to a settlement or filtration tank, from which it flows into the recharge well (borewell or dugwell).

If a tubewell is used for recharging, then the casing (outer pipe) should preferably be a slotted or perforated pipe so that more surface area is available for the water to percolate. Developing a borewell would increase its recharging capacity (developing is the process where water or air is forced into the well under pressure to loosen the soil strata surrounding the bore to make it more permeable).

If a dugwell is used for recharge, the well lining should have openings (weep-holes) at regular intervals to allow seepage of water through the sides. Dugwells should be covered to prevent mosquito breeding and entry of leaves and debris. The bottom of recharge wells should be desilted annually to maintain the intake capacity.

Providing the following elements in the system can ensure the quality of water entering the recharge wells:

1. Filter mesh at entrance point of rooftop drains

3. Filter bed

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2. Settlement Tank

Settlement tanks are used to remove silt and other floating impurities from rainwater. A settlement tank is like an ordinary storage container having provisions for inflow (bringing water from the catchment), outflow

(carrying water to the recharge well) and overflow. A settlement tank can have an unpaved bottom surface to allow standing water to percolate into the soil.

In case of excess rainfall, the rate of recharge, especially of borewells, may not match the rate of rainfall. In such situations, the desilting chamber holds the excess amount of water till it is soaked up by the recharge structure. Thus, the settlement chamber acts like a buffer in the system.

Any container, (masonry or concrete underground tanks, old unused tanks, pre-fabricated PVC or ferrocement tanks) with adequate capacity of storage can be used as a settlement tank.



1.

Recharging of service tubewells.

In this case the rooftop runoff is not directly led into the service tubewells, to avoid chances of contamination of groundwater. Instead rainwater is collected in a recharge well, which is a temporary storage tank (located near the service tubewell), with a borehole, which is shallower than the water table.

This borehole has to be provided with a casing pipe to prevent the caving in of soil, if the strata is loose.

A filter chamber comprising of sand, gravel and boulders is provided to arrest the impurities.

2.

Recharge pits – Lubang Resapan

A recharge pit is 1.5m to 3m wide and 2m to 3m deep. The excavated pit is lined with a brick/stone wall with openings (weep-holes) at regular intervals. The top area of the pit can be covered with a perforated cover. Design procedure is the same as that of a settlement tank.

3.

Soakaways / Percolation pit – Lubang Perkolasi

Filter materials in a soakaway

Percolation pits, one of the easiest and most effective means of harvesting rainwater, are generally not more than 60 x 60 x 60 cm pits, (designed on the basis of expected runoff as described for settlement tanks), filled with pebbles or brick jelly and river sand, covered with perforated concrete slabs wherever necessary.

Filter materials in a soakaway


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6. Recharge trenches

A recharge trench is a continuous trench excavated in the ground and refilled with porous media like pebbles, boulders or broken bricks.

A recharge trench can be 0.5 m to 1 m wide and 1 m to 1.5 m deep. The length of the recharge trench is decided as per the amount of runoff expected.

The recharge trench should be periodically cleaned of accumulated debris to maintain the intake capacity.

In terms of recharge rates, recharge trenches are relatively less effective since the soil strata at depth of about

1.5 metres is generally less permeable.

For recharging through recharge trenches, fewer precautions have to be taken to maintain the quality of the rainfall runoff.

Runoff from both paved and unpaved catchments can be tapped.



7. Recharge troughs

To collect the runoff from paved or unpaved areas draining out of a compound, recharge troughs are commonly placed at the entrance of a residential/ institutional complex.These structures are similar to recharge trenches except for the fact that the excavated portion is not filled with filter materials.

In order to facilitate speedy recharge, boreholes are drilled at regular intervals in this trench. In design part, there is no need of incorporating the influence of filter materials.

This structure is capable of harvesting only a limited amount of runoff because of the limitation with regard to size.

Source: A water harvesting manual for urban areas


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KOMPONEN SISTEM

PEMANEN AIR HUJAN

8. Modified injection well

(Modifikasi Sumur Injeksi)

In this method water is not pumped into the aquifer but allowed to percolate through a filter bed, which comprises sand and gravel.

A modified injection well is generally a borehole,

500 mm diameter, which is drilled to the desired depth depending upon the geological conditions, preferably 2 to 3 m below the water table in the area. Inside this hole a slotted casing pipe of 200 mm diameter is inserted. The annular space between the borehole and the pipe is filled with gravel and developed with a compressor till it gives clear water. To stop the suspended solids from entering the recharge tubewell, a filter mechanism is provided at the top.


PANEN AIR HUJAN

Memanen Air hujan dengan Hutan Genangan Air-Tawar

Rain water harvesting is possible by growing fresh water flooded forests without losing the income from the used /submerged land.

The main purpose of the rain water harvesting is to utilize the locally available rain water to meet water requirements throughout the year without the need of huge capital expenditure. This would facilitate availability of uncontaminated water for domestic, industrial and irrigation needs.

UTILITY OF FRESH WATER FLOODED FORESTS IN INDIA

( N. Sasidhar. : http://www.scribd.com/doc/58789361/Rain-Water-Harvesting-by-Freshwater-

Flooded-Forests )

There are vast areas of fresh water flooded forests in Amazon River, Mekong River andMeghna

River (Bangladesh) basins. In these flooded forests, the flora & fauna is richer than tropical ever green forests and many tree species grow more than 20 meters inheight. These forests are inundated / submerged by river flood water up to ten metersdepth for 5 to 7 months duration at a stretch. The portion of forest under the water,remain verdant similar to the portion above the water level.Many trees with commercial value yielding fruits, seeds, timber, fodder, herbs, biodiesel,etc are native to flooded forests. In flooded forests, the fish growth is also veryencouraging as they feed on tree seeds, fruits, vegetation, etc


PANEN AIR HUJAN

Memanen Air Hujan:

The flooded forest plants/trees are very useful in rain water harvesting / ground water recharging anywhere such as house plots, farm lands, forest lands, open areas, river courses, etc. Rain water wherever available and needed are stored in small pits/ponds/tanks by growing ‘flooded forest trees’ which will earn income exceeding that of normalcrops /trees.

Recharging rain water in the house compounds:

1.

Mmebuat lubang resapan air hujan.

Make a pit of 1.5 meters depthwith sufficient storage volume to collect moderate fortnight rain fall. Plant the ‘flooded forest trees’ in this pond area. When there is rain, the rain water collectsin this pond and slowly percolates in to the ground building up ground water.Thus trees can be grown and the ground water is recharged simultaneously for dryseason drinking water purpose.

1.

Meresapkan air hujan pada lahan terbuka di wilayah desa dan kota :

Build a check damto store water up to 1.5 meters depth and plant ‘flooded forest trees’ in the water stored area. The entire area becomes woody area in few years and also the groundwater is recharged.

3.

Memanen Air Hujan di Lahan PErtanian:

Generally the time gap between good rains is 15or more days. It is very useful to store the rain water in a small area of the fieldand use it to water the crop till the next rain. Thus the crop yield is assured evenin erratic rain fall. Create a pond of depth 1.5 meters in 5% area of the field and plant the ‘flooded forest trees’. Thus the pond area land also contributes equallyfor agriculture produce and stores water for the needs of the crop.

4.

Memanen Air Hujan di Lahan Hutan:

On the small streams in the forest area,construct check dams of nearly 1.5 meters high and plant ‘flooded forest trees’

Diunduh dari: N. Sasidhar. : http://www.scribd.com/doc/58789361/Rain-Water-Harvesting-by-Freshwater-Flooded-Forests subsoil moisture will help the forest in preventing water stress during summer months. Thus the growth of the forest

)

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Rainwater Harvesting Basic Components

Rainwater systems come in all shapes and sizes, from simple catchment system under a downspout to large above and/or underground cisterns with complex filtration systems that can store thousands of gallons of water. Most rainwater collection systems are comprised of the following basic components:

1.

Catchment surface - rooftop or other raised solid surface. The best catchment systems have hard, smooth surfaces such as metal roofs or concrete areas. The amount of water harvested depends on the quantity of rainfall, and the size of the surface and the slope of the catchment area.

2.

Gutters and downspouts - also known as distribution systems that channel the water from the catchment area to a holding container such as a barrel, cistern, planted area, etc.

3.

Leaf screens - a screen that removes or catches debris.

4.

Roof washers - a device that diverts the "first flush" of rain before it enters the storage tank. Most rainwater suppliers recommend that the "first flush" of water is diverted to an outside area of the storage system, since the catchment surface may accumulate bird droppings, debris and other pollution.

5.

Storage tanks - In general, the storage tank is the most expensive component of a rainwater harvesting system. There are numerous types and styles of storage tanks available. Storage can be above-ground or underground. Storage containers can be made from galvanized steel, wood, concrete, clay, plastic, fiberglass, polyethylene, masonry, etc.

Examples of above-ground storage include; cisterns, barrels, tanks, garbage cans, above ground swimming pools, etc.

Storage tank prices vary based on different variables such as size, material and complexity. To inhibit the growth of algae, storage tanks should be opaque and preferably placed away from direct sunlight. The tanks should also be placed close to the areas of use and supply line to reduce the distance over which the water is delivered. Also consider placing the storage at an elevated area to take advantage of gravity flow. The tank should always be placed on a stable and level area to prevent it from leaning and possibly collapsing.

6.

Delivery systems - gravity-fed or pumped to the landscape or other end use areas.

7.

Purification/treatment system - needed for potable systems to make the water safe for human consumption. Please check with your local health department for information on filtration systems and certification requirements.

Diunduh dari: http://www.sandiego.gov/water/conservation/rainwater.shtml ………… 18/1/2013

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KEUNTUNGAN DAN KERUGIAN

Keuntungan Panen Air Hujan

1.

Makes use of a natural resource and reduces flooding, storm water runoff, erosion, and contamination of surface water with pesticides, sediment, metals, and fertilizers

2.

Reduces the need for imported water (the San Diego region imports between 80%-90% of its water from

Northern California and Colorado River)

3.

Excellent source of water for landscape irrigation, with no chemicals such as fluoride and chlorine, and no dissolved salts and minerals from the soil

4.

Home systems can be relatively simple to install and operate May reduce your water bill

5.

Promotes both water and energy conservation

6.

No filtration system required for landscape irrigation

Kerugian / Kelemahan Panen Air Hujan

1.

Limited and uncertain local rainfall

2.

Can be costly to install - rainwater storage and delivery systems can cost between $200 to $2,000+ depending on the size and sophistication of the system

3.

The payback period varies depending on the size of storage and complexity of the system

4.

Can take considerable amount of time to "pay for itself"

5.

Requires some technical skills to install and provide regular maintenance

6.

If not installed correctly, may attract mosquitoes (i.e.; West Nile Disease and other waterborne illnesses)

7.

Certain roof types may seep chemicals, pesticides, and other pollutants into the water that can harm the plants

8.

Rainwater collected during the first rain season is generally not needed by plants until the dry season.

Shivakumar offered to take us on a tour of his eco-friendly house Sourabha, in Vijayanagar, to display his advanced rain water harvesting system that makes him completely independent of Bangalore Water Supply and Sewerage Board (BWSSB).

Shivakumar’s wife Suma is used to his eccentricities as a scientist.

Diunduh dari: http://myviews4life.wordpress.com/tag/rain-water/ ………… 18/1/2013

Low Energy House - Rainwater Harvesting - Water Collection

A Rainwater Harvesting System can be installed in a house to reduce mains water usage and maintain water supplies in periods of drought

Rainwater Harvesting System Design

Rainwater harvesting is a specialised field so when considering an installation it is advisable to takes the advice of a competent installer. The rainwater harvesting system must be designed so that the supply of rain water meets the demand. Rainfall is intermittant so it will be necessary to store enough rainwater to avoid running out in dry spells.

Diunduh dari: http://www.lowenergyhouse.com/rainwater-harvesting.html ………… 18/1/2013

MEMANEN AIR HUJAN

How to save 50% on metered water costs

The UK practice of using mains water to supply all our water needs is needlessly wasteful, both financially and environmentally. Mains water is expensively purified to drinking water standards

- but much of the water is used for non-potable purposes, like flushing toilets, cleaning and gardening. Harvested rainwater can be substituted for mains water, saving money and contributing to the protection of a key natural resource.

Diunduh dari: http://www.constructionresources.com/products/services/rainwater_overview.asp ………… 18/1/2013

SISTEM PANEN AIR HUJAN YANG LEBIH BAIK

Think beyond the rain barrel: This simpler, cheaper approach to rainwater harvesting will help you harvest much more water for your garden!

By Cheryl Long. August/September 2012

Read more: http://www.motherearthnews.com/modern-homesteading/rainwater-harvestingzm0z12aszhun.aspx#ixzz2IGyDrW4J

Harvesting rainwater to use for growing vegetables makes a great deal of sense. Unfortunately, the most common method of rainwater harvesting isn’t the most effective. Typically, gardeners invest in a rain barrel — which holds only 50 or 60 gallons of water

— and then dole out the captured water to plants as needed, hopefully emptying the barrel before the next storm.

Read more: http://www.motherearthnews.com/modernhomesteading/rainwater-harvestingzm0z12aszhun.aspx#ixzz2IGyl2MQI

Diunduh dari: http://www.motherearthnews.com/modern-homesteading/rainwater-harvesting-zm0z12aszhun.aspx …………

18/1/2013

KOMPONEN – DESAIN – KONSTRUKSI

Components - Design -

Construction

The components of rainwater harvesting systems include:

1. catchment

2. conveyance or conduit system

3. first flush

4. filters

5. storage or recharge system

Diunduh dari: http://cseindia.org/category/thesaurus/rainwaterharvesting………… 18/1/2013

MEMANEN AIR HUJAN

1. Rainwater harvesting involves collection and storage of rainwater for future use.

2. Rainwater can also be discharged into the ground without loss through evaporation or seepage.

Rainwater can be recharged into the ground.

The main components of a rainwater harvesting system are:

1. The catchment area where the water is collected.

2. The conduits through which the harvested water is carried.

3. Storage and recharge facilities where the harvested water is stored or recharged into the ground.

Diunduh dari: http://ncict.net/Parameters/WaterHarvesting1.aspx ………… 18/1/2013

RAIN GARDENS

.

A rain garden is a planted depression or a hole that allows rainwater runoff from impervious urban areas like roofs, driveways, walkways, parking lots, and compacted lawn areas the opportunity to be absorbed. This reduces rain runoff by allowing stormwater to soak into the ground (as opposed to flowing into storm drains and surface waters which causes erosion, water pollution, flooding, and diminished groundwater). They can be designed for specific soils and climates. The purpose of a rain garden is to improve water quality in nearby bodies of water. Rain gardens can cut down on the amount of pollution reaching creeks and streams by up to 30%.

Native plants are recommended for rain gardens because they generally do not require fertilizer and are more tolerant of one’s local climate, soil, and water conditions, and attract local wildlife such as native birds. The plants — a selection of wetland edge vegetation, such as wildflowers, sedges, rushes, ferns, shrubs and small trees — take up excess water flowing into the rain garden. Water filters through soil layers before entering the groundwater system.

Root systems enhance infiltration, maintain or even augment soil permeability, provide moisture redistribution, and sustain diverse microbial populations involved in biofiltration. Also, through the process of transpiration, rain garden plants return water vapor to the atmosphere.

A more wide-ranging definition covers all the possible elements that can be used to capture, channel, divert, and make the most of the natural rain and snow that falls on a property. The whole garden can become a rain garden, and each component of the whole can become a small-scale rain garden in itself.

Diunduh dari: http://en.wikipedia.org/wiki/Rain_garden………… 18/1/2013

RAIN GARDENS

A rain garden requires an area where water can collect and infiltrate, and plants to maintain infiltration rates, diverse microbe communities, and water holding capacity. Transpiration by growing plants accelerates soil drying between storms. This includes any plant extending roots to the garden area.

Simply adjusting the landscape so that downspouts and paved surfaces drain into existing gardens may be all that is needed because the soil has been well loosened and plants are well established.

However, many plants do not tolerate saturated roots for long and often more water runs off one's roof than people realize. Often the required location and storage capacity of the garden area must be determined first. Rain garden plants are then selected to match the situation, not the other way around.

When an area’s soils are not permeable enough to allow water to drain and filter properly, the soil should be replaced and an underdrain installed. This bioretention mixture should typically contain 60% sand , 20% compost , and 20% topsoil . Existing soil must be removed and replaced. Do not combine the sandy soil

(bioretention) mixture with a surrounding soil that does not have high sand content. Otherwise, the clay particles will settle in between the sand particles and form a concrete-like substance. Deep plant roots also create additional channels for storm water to filter into the ground. Microbial populations feed off plant root secretions and break down carbon (such as in mulch or desiccated plant roots) to aggregate soil particles which increases infiltration rates.

A five year USGS study indicates that rain gardens in urban clay soils can be effective without the use of underdrains or replacement of native soils with the bioretention mix. Pre-installation infiltration rates should be at least .25 in/hour, however. Type D soils will require an underdrain paired with the sandy soil mix in order to drain properly.

Diunduh dari: http://en.wikipedia.org/wiki/Rain_garden………… 18/1/2013

Perlunya tumbuhan pada suatu RAIN-GARDEN

As we all know, freshwater is becoming increasingly scarce due to pollution despite its increasing necessity.

Thankfully, rain help garden reduce pollution and preserve our water system by keeping clean and fresh rainwater out of the sewer system. It can capture the runoff and hold not only thousands of gallons of rainwater that can be used in your own garden and yard but all of the pollutants that contaminate our waterways. After that, the water will infiltrate deep into the ground so that it can be used by nearby plants and trees.

Saving the earth may sound like a grand and complicated work which should be assigned to ecologists.

However, just by planting a rain garden and spreading the words, you can improve the community the world you live in. Will this be enough of an reason for you to plant a rain garden? Oh and also, rain garden is quite beautiful. You can impress your neighbors not only by its gorgeous look but also by its function as a habitat fo birds and beneficial insects.

Diunduh dari: http://fuzeus.wordpress.com/2012/09/04/a-beautiful-rain-garden-at-absolutely-no-cost-for-any-laresidents/………… 18/1/2013

RAIN GARDENS: One size fits all

When planning the garden’s construction, the first principle to remember is that any sized rain garden is better than no rain garden at all. However, if you want to take a scientific approach to minimize rooftop runoff, start by calculating the size of your roof. For example, let’s say that your roof is 186 square metres and that rainwater runs to each corner equally. That means that each of the four down spouts drains about 46 square metres of roof. Next (stay with me now!), divide the 46 square metres by 6 (because someone somewhere discovered that was the magic number) to determine the optimum size of garden you need, which in this case is about 8 square metres.

The construction is relatively simple. Choose a location that’s not on too steep of a slope (this will eliminate erosion), dig the garden to a depth of 15 cm and ensure that you have well-drained soil—the sandier, the better. A good way to test your soil for drainage is to dig a 15-cm deep trial ‘pit’ and to fill it with water. If it drains within 24 hours, you’re set. If water remains after 24 hours, either replace the soil or amend it with a mixture of coarse sand and loam. The only step that’s left after that is to plant the entire rain garden (not just the periphery) with suitable plants.

Diunduh dari: http://water.greenventure.ca/rain-gardens ………… 18/1/2013

1.

Slow Down, Soak In & Clean Up Stormwater -

Naturally

View the Rain Gardens signage placed at Griggs

& Hoover Reservoirs

2.

How Do They Work?

When it rains, a rain garden acts as a basin to capture and absorb water runoff.

.

Nutrients, oils and other pollutants are then filtered by the soil and plants.

Deep roots and pervious soils help to slow stormwater's flow, filtering out pollutants and keeping surface & ground water cleaner.

3.

Water Fact: Did You Know?

Rain gardens absorb 30% more water than the same size area of turfgrass.

4.

Plant A Beneficial Bouquet of Natives

Ohio-native plants have deep root systems and tolerate drought. This means less maintainance & watering. They also provide wildlife habitat.

5.

Sow the Seeds, Reap the Benefits

Plant a rain garden in your yard to protect water quality and:

Reduce lawn maintainance

Minimize area flooding

Recharge groundwater

RAIN-GARDEN di halaman rumah

Diunduh dari: http://publicutilities.columbus.gov/content.aspx?id=53917 ………… 18/1/2013

Iowa Rain Garden Design Manual

Diunduh dari: http://stopmountaintopremoval.blogspot.com/2012/08/rain-garden-design.html ………… 18/1/2013

Concept drawing of example Rain Garden

When using Rain Gardens, it is advisable to:

1. Use more and smaller rain gardens than using few larger ones

2. Contributing catchments should be limited to ~0.1 ha

3. Design as off-line systems

4. Aesthetically designed systems will encourage greater public support and acceptance

Diunduh dari: http://wsud.melbournewater.com.au/content/treatment_measures/rain_gardens/design_details.asp ………… 18/1/2013

AIR HUJAN

UNTUK

MENGATASI KELANGKAAN

AIR BERSIH

KUALITAS AIR HUJAN

Microbial contamination of collected rainwater indicated by E. coli (or, alternatively, thermotolerants coliforms) is quite common, particularly in samples collected shortly after rainfall. Pathogens such as Cryptosporidium, Giardia, Campylobacter, Vibrio, Salmonella,

Shigella and Pseudomonas have also been detected in rainwater.

However, the occurrence of pathogens is generally lower in rainwater than in unprotected surface waters, and the presence of non-bacterial pathogens, in particular, can be minimized.

Higher microbial concentrations are generally found in the first flush of rainwater, and the level of contamination reduces as the rain continues.

A significant reduction of microbial contamination can be found in rainy seasons when catchments are frequently washed with fresh rainwater.

Storage tanks can present breeding sites for mosquitoes, including species that transmit dengue virus.

Diunduh dari: https://docs.google.com/viewer?a=v&q=cache:GEXXuPgYvpEJ:www.who.int/water_sanitation_health/gdwqrevision/rainwater.pdf+&hl=en&pid=bl&srcid=A

DGEEShSyNPyhojWp-m0eII8ncj63YVUaob62uGVrThNXfz-b6eQjB6YUI-



KUALITAS AIR HUJAN

Rainwater is slightly acidic and very low in dissolved minerals; as such, it is relatively aggressive. Rainwater can dissolve heavy metals and other impurities from materials of the catchment and storage tank.

In most cases, chemical concentrations in rainwater are within acceptable limits; however, elevated levels of zinc and lead have sometimes been reported.

This could be from leaching from metallic roofs and storage tanks or from atmospheric pollution.

Diunduh dari: https://docs.google.com/viewer?a=v&q=cache:GEXXuPgYvpEJ:www.who.int/water_sanitation_health/gdwqrevision/rainwater.pdf+&hl=en&pid=bl&srcid=ADGEES hSyNPyhojWp-m0eII8ncj63YVUaob62uGVrThNXfz-b6eQjB6YUI-

5AuzOijRNqyZ6n49GCOffBXZp9Ahutj9AFUVaP0Kr6b70P8TaUn8MJqor_o1onUX2Wzte0987I_89imvb&sig=AHIEtbQVuuDWjOa-31OfDvnjAqyVWhE7Pg

………… 18/1/2013

Faktor-faktor yang menentukan kualitas air hujan yang dipanen

Water quality is determined by the composition of water as affected by natural processes and human activities. Water quality depends on the constituents dissolved or contained within the water. It is often presumed that the chemical composition of water is the only factor involved.

However, especially (micro) biological factors are of main importance when considering water quality.

Diunduh dari: http://webcache.googleusercontent.com/search?q=cache:yUYlQg6UFloJ:www.rainfoundation.org/fileadmin/PublicSite/Manuals/RAIN_Rainwate r_Quality_Policy_and_Guidelines_2009_v1.pdf+&hl=en ……….. 19/1/2013

KONTAMINASI AIR HUJAN

Atmospheric pollution can have a major effect on the composition of rainwater. Water that reaches the earth as rain, acquires other substances from processes such as leaching, weathering, and dissolution. Living organisms may enter the water. All these processes affect the composition of the water. Depending on the source of the contamination, three types can be distinguished:

1. (Micro)biological contamination:

The most common hazard in water sources obtained from roof or surface catchments is microbial (biological and microbiological) contamination, especially enteric pathogens. Enteric pathogens are micro-organisms

(bacteria, viruses, and protozoa) that cause gastrointestinal illness. These organisms are introduced into drinking water supplies by contamination with faecal material (from human or animal origin) or dead animals and insects (enHealth, 2004). The most important indicator is E-Coli.

2. Chemical contamination:

Chemical contamination results from air pollution (industrial and traffic emissions), runoff and leaching of chemical substances (agricultural and human activities) and toxic material use. All these factors can pose a serious a health threat. However, in rural areas of developing countries, these activities are mostly absent or very small- scale (for example: fireplaces near a roof or having a chimney can cause soot to settle on the roof), and are therefore unlikely to cause significant impacts on the quality of the collected rainwater

(enHealth, 2004).

3. Physical contamination:

Physical contamination includes inorganic and organic sediments like sand, silt, clay, or plant material.

Physical contamination affects the colour, odour or taste of the water, but it poses no direct health risk. Users can however object to water if its colour, odour and taste are found less attractive

Diunduh dari: http://webcache.googleusercontent.com/search?q=cache:yUYlQg6UFloJ:www.rainfoundation.org/fileadmin/PublicSite/Manuals/RAIN_Rainwate r_Quality_Policy_and_Guidelines_2009_v1.pdf+&hl=en ……….. 19/1/2013

KUALITAS AIR HUJAN

RAINs water quality criteria

Based on the WHO Guidelines for Drinking Water Quality (2004), water quality analyses from RAINs water quality surveys in Burkina Faso, Ethiopia en Nepal in 2007, RAIN has set water quality criteria for potable water as listed in the table below.

RAINs criteria for water quality based on WHO guidelines.

Roofwater harvesting Surface Runoff Sand dams

< 10 cfu/100 ml E-Coli

Ammonia < 1.5 mg/l

<10 cfu/100 ml

< 1.5 mg/l

<10 cfu/100 ml

< 1.5 mg/l

Khlorine > 0.2 – 0.5 and < 5 mg/l > 0.2 – 0.5 and < 5 mg/l > 0.2 – 0.5 and < 5 mg/l

Aluminium pH

Turbiditas

Nitrate / Nitrite

Not relevant

6.5.- 8.5

Not relevant

Not relevant

< 0.2 mg /l

6.5 – 8.5

< 15 NTU

< 50 mg/l and < 3 mg/l

< 0.2 mg /l

6.5 – 8.5

< 5 NTU

< 50 mg/l and < 3 mg/l

Diunduh dari: http://webcache.googleusercontent.com/search?q=cache:yUYlQg6UFloJ:www.rainfoundation.org/fileadmin/PublicSite/Manuals/RAIN_Rainwater_Quality_Pol icy_and_Guidelines_2009_v1.pdf+&hl=en ……….. 19/1/2013

KUALITAS AIR HUJAN

Baseline and long-term water quality survey

After the first rainy season after completion of a RWH system, a water quality survey should be done. This survey will also give a general idea of the performance of each system, the skills of construction of the implementing partner and the community operation and management. The results of this first survey will lead to fine-tuning of RWH system; identifying construction flaws, identifying operational, maintenance and management flaws and selecting most optimal treatment measures.

RAINs methodology for water quality surveys

Baseline survey Long-term survey

Period

Nr. of RWH systems

After 1st rainy season after construction

All RWH systems constructed that year

After rainy season

Random selection of 30% of all tanks (> 1 year old)

Parameters

Period

All parameters Roofwater harvesting:

• E-Coli,

• Chlorine, if chlorination has been applied.

November – December

Diunduh dari: ……….. 19/1/2013

Surface runoff and sand dams:

• E-Coli,

• Turbidity,

• Chlorine, if hlorination has been applied,

• Aluminium, if it has been applied.

KUALITAS AIR HUJAN

Risks to human health and aesthetic acceptance of RAIN water quality criteria

E-Coli or faecal coliforms

Examples of diseases which are waterborne (caused by contaminated drinking water) include cholera, typhoid, hepatitis, amoebiasis, and dracunculiasis. The causes of the high levels of contamination/pollution of surface water are often due to hanging latrines and direct sewage discharge (without any minimum treatment etc.) into surface waters and close proximity of latrines or drains (WaterAid, 2008).

Ammonia

Ammonia is an indicator of water pollution caused due to human activities and natural decay processed. Harvested rainwater may contain ammonia as a result of the decay process in the storage tank. Groundwater often contains some ammonia due to natural reduction of nitrate by bacteria, but sudden change in ammonia may be due to contamination of wastewater through seepage (WaterAid, 2008).

Chlorine

Free (or residual) chlorine in drinking water is only relevant where supplies are chlorinated, or where routine or emergency chlorination has taken place. The presence of free (residual) chlorine is an indication that removal of bacterial contamination is continuing within the supply. Exposure to extremely high levels of pure chlorine gas can cause lung collapse and death (WaterAid, 2008).

Aluminium

In humans, aluminium and its compounds appear to be poorly absorbed, although the rate and extent of absorption have not been adequately studied for all sectors of the population. There is little indication that orally ingested aluminium is acutely toxic to humans despite the widespread occurrence of the element in foods, drinking-water and many antacid preparations. It has been hypothesized that aluminium exposure is a risk factor for the development or acceleration of onset of Alzheimer disease (AD) in humans (Guidelines for Drinking Water Quality, WHO, 2004).

Diunduh dari: ……….. 19/1/2013

KUALITAS AIR HUJAN

Risks to human health and aesthetic acceptance of RAIN water quality criteria pH

According to the WHO guidelines, no health-based guideline value is proposed for pH, although eye irritation and exacerbation of skin disorders have been associated with pH values greater than 11. Although pH usually has no direct impact on consumers, it is one of the most important indicative water quality parameter for operational management, since pH determines the effectiveness of the treatment (WaterAid, 2008).

Turbidity

Turbidity which is a measure of extent to which light is either absorbed or scattered by suspended materials in water is an indicator of suspended solids present in water. These suspended solids can be in the form of silt, clay, sand, industrial wastes, sewage, organic matter, phytoplankton and other microbial organisms. Turbidity is an important parameter to be considered in drinking water supplies due to aesthetics, filterability and disinfection. Turbidity is also measured to determine what type and level of treatment are needed (WaterAid, 2008).

Nitrate and Nitrite

Nitrate is the most widespread agriculture contaminant but presence of nitrate/nitrite is considered to have minimal effect on the disease burden. The WHO guideline value for nitrate in drinking water of 50mg/litre (equivalent to

10mg/litre nitrate-nitrogen) and 3mg/l for nitrite (short-term exposure) is established solely to prevent Cyanosis

(methaemoglobinaemia) in babies: bottle-fed infants of less than 3 months of age are most susceptible although occasional cases have been reported in some adult populations. The long term exposure to Nitrate/Nitrite is, however, a human health concern as it may increase stomach cancer. A recent study suggested that miscarriage might also be linked to high nitrate levels, although scientists have not confirmed this (WaterAid, 2008).

Diunduh dari: ……….. 19/1/2013

System assessment: mapping the risks of contamination

Generally treating and filtering of water seems the obvious method for obtaining a certain water quality. This, however, is an end-of-pipe solution. If contamination resulted from for example use of toxic materials or by poor maintenance, re-contamination will certainly occur.

By following a top-down method of preventing contamination, a more cost-effective approach can be reached.

Area

Pemetaan risiko kontaminasi pada sistem Pemanenan air hujan

(based on www.eng.warwick.ac.uk/DTU/rwh/components1.html)

Industrial, agricultural or human activities influencing water quality by air, water or soil

Catchment surface

Conveyance

Storage

Delivery

Roof, paved or unpaved surface, dry riverbed, maintenance

Gutters, inlet constructions or riverbeds, maintenance

RWH systems, maintenance

Taps, hand pumps, operation and management

Preven-tion

Filtra-tion

Treat-ment

Filtra-tion


KUALITAS AIR HUJAN

Faktor Keadaan Area

The area can be described as the external factors influencing the background or reference water quality in a RWH system and can be divided into physical and social factors:

1. Physical factors:

The air, water and soil pollution present within the area, resulting from industrial and agricultural activities and geology directly influences the water quality of the

RWH system. Mostly these factors are difficult to influence, but should be taken into account when starting a RWH project. In rural areas their influence is relatively small and can often be excluded, but can reflect unexpected outcomes in water quality tests.

2. Social factors:

Human conduct and level of education, reflected in the level of awareness of the relation between water and health, hygiene and sanitation, management and maintenance skills of RWH systems are social factors controlling water quality of a

RWH system.


KUALITAS AIR HUJAN

Permukaan Daerah Tangkanan air hujan

The catchment surface can be described as the area on which the rainfall is collected. Depending on the type of RWH system, several catchment surfaces can be defined, i.e. roofs, paved or unpaved surfaces, dry sandy river beds.

Contamination can be prevented by:

1.

Using non-toxic materials for roofing, like cement, corrugated and galvanised iron. Metal roofs subjected to atmospheric corrosion can act as a source of heavy metals;

2.

Frequently cleaning and clearing of the catchment surface (from human, animal and organic matter), removing overhanging branches and fencing off of the catchment area in the case of surface runoff.

Faecal contamination of water from rooftops can result from animal droppings on the roof surface. Water harvested from ground surfaces is vulnerable to contamination by animal or human faeces. The larger the catchment surface, the bigger the chance for contamination due to more complex management of the catchment.


KUALITAS AIR HUJAN

Penyaluran Air Hujan

The conveyance can be described as the means of transportation of the collected rainfall from the catchment surface to the storage system. Depending on the type of RWH systems, several conveyances can be defined: gutters, inlet pipes, and collection and inlet canals.

Contamination can be prevented by:

1.

Using non-toxic materials;

2.

Frequently cleaning of the conveyances. Debris and pools should not remain in the gutters, since they can become pools of contamination.

Contamination might have occurred in the previous level (the catchment area). Therefore filters should be installed at the entrance or end of the gutters or inlet canals to prevent (small) animals, organic matter and debris from entering the RWH system.

A first-flush device should be installed to divert the first (millimetres of) rainfall, which contains the main load of pollution.


PEMANENAN AIR HUJAN

Penyimpanan Air Hujan

The storage can be described as the structure or medium in which the rainwater is stored. In

RAINs current programme three different types of RWH systems can be defined: above ground tanks, below ground tanks and sand dams. Contamination can be prevented by:

1.

Using non-toxic construction materials;

2.

Using adequate covering to prevent influence from direct sunlight, human, animal and organic matter from entering the storage system and mosquito breeding.

Contamination might have occurred in the previous levels. Treatment of the water can be applied when found necessary (see table 1 and annexes 3 a, b and c). Residence in the storage system itself provides opportunities for water purifying processes such as sedimentation, bacterial die-off and filtration (for sand dams), increasing the water quality over time. Cleaning of the storage system should only be done if the previous water was found to be contaminated (see annex 6). Surface runoff storage systems will contain a lot of soil material which has to be removed every year when the tank is empty (before the rainy season) since it not only affects the water quality, but also decreases the tank capacity. Sand dams have no closed storage system which makes it even more important to limit contamination risks as much as possible in the previous levels.

Other possible risks of contamination at the storage level are:

1.

Frequent opening of the manhole. Although many people see opening of the manhole as necessary to investigate the water quality (by colour, odour, debris etc); it will pose a bigger risk to contamination since debris might fall into the tank. Children sometimes use the tank to bath in, which is not only dangerous, but will increase risks of contamination.

2.

Mixing of tank water or filling of a tank with water from other sources. If water from another source has been tested and found not contaminated, the water can be mixed under well-controlled circumstances with the water in the RWH system.

If the water is not tested, chlorination should always be applied after mixing with the water in the RWH system.

•


PEMANENAN AIR HUJAN

Distribusi Air Hujan (Delivery)

The delivery can be described as delivery point to the user, hence the pump or tap by which the user fetches the water.

Kontaminasi air hujan dapat dicegah dnegan jalan:

1.

Proper management of the water distribution;

2.

Creating awareness on hygiene issues (hygiene education). People can contaminate the water by nonhygienic use of the taps or pumps, as well as use of unclean containers after extraction.

3.

Closing the area around the delivery point for animals, because they can infect the water by drinking from the (leaking) taps or pumps;

4.

Preventing water pools around the RWH systems which could enhance mosquito breeding for example by increasing the infiltration capacity of the soil at the delivery point (gravel). The picture on the right shows a good example of increasing the infiltration capacity near the tap of an above ground tank.


PANEN AIR HUJAN: Improving water quality

Recommended treatment and filtering methods

Water treatment only makes sense if it is done properly, and if hygienic collection, storage and use of water ensure prevention of recontamination. Due to the fact that RAIN works in remote areas, a selection has been made of practical and acknowledged treatment and filter techniques, presented in table 1. Until now RAIN only has had experience with chlorination.

RAINs recommended treatment and filtering methods for RWH systems

Treatment method Roof runoff Surface runoff Sand dam

Solutions or substances to be added to water:

Chlorination Tank Household Household

Silver coated ceramic balls Tank Household Household

Aluminium sulphate Household /Tank Household

Filters:

Heat and UV radiation:

Moringa oleifera and stenopetala

Ceramic pot filter

Bio-sand filter

Boiling

SODIS

Household

Household

Household

Household

Household/ Tank

Household

Household

Household

Household

Household

Household

Household

Household

Household


KERANGKA-KERJA Perbaikan Higienis Air Hujan

Hygiene promotion works best when combined with improvements in water supply and sanitation services. The

Environmental Health Project EHP therefore developed the Hygiene Improvement Framework (HIF), which combines the multiple fronts to fight water-related diseases and uses lessons learned from y ears of program experience. Three key elements can be defined: access to the necessary technologies, promotion of healthy behaviours, and support to ensure longterm sustainability. The HIF can be used as a framework to find the missing elements within a water supply and sanitation project.

Sanitation and hygiene play an important role in water supply projects. However RAIN will focus on providing sufficient and safe drinking water and will seek collaborations with national or international organisations with experience on sanitation and hygiene.

1.

2.

3.

The Hygiene Improvement Framework (The Hygiene Improvement Framework, 2004).

Access to Water and

Sanitation

Water supply systems

Sanitation Facilities

Household-level technologies and materials

Access to Water and

Sanitation

1.

Behavioral / Social change methods

2.

Community mobilization

3.

Social Marketing

4.

School programs

5.

Community participation in problem identification and Solutions

Enabling Environments

1.

Policy improvement

2.

Institutional strengthening

3.

Community involvement

4.

Financing and cost recovery

5.

Cross-sector and public-private partnerships

Hygiene Improvement


KUALITAS AIR HUJAN

Rainwater lacks minerals, but some minerals, such as calcium, magnesium, iron and fluoride, in appropriate concentrations are considered very essential for health.

Although most essential nutrients are derived from food, the lack of minerals, including calcium and magnesium, in rainwater may represent a concern for those on a mineraldeficient diet.

In this circumstance, the implications of using rainwater as the primary source of drinking-water should be considered. The absence of minerals also means that rainwater has a particular taste or lack of taste that may not acceptable to people used to drinking other mineral-rich natural waters.

Water quality should be managed through development and application of WSPs that should deal with all components from catchment areas to point of supply.





KUALITAS AIR HUJAN

The first flush of rainwater carries most contaminants into storages. A system is, therefore, necessary to divert the contaminated first flow of rainwater from roof surfaces.

Some devices and good practices are available to divert the first foul flush of rainwater.

Automatic devices that prevent the first 20–25 litres of runoff from being collected in storages are recommended. If diverters are not available, a detachable down-pipe can be used manually to provide the same result. Even with these measures in place, storages will require periodic cleaning to remove sediment.

Storages without covers or with unprotected openings will encourage mosquito breeding, and sunlight reaching the water will promote algal growth. Covers should be fitted, and openings need to be protected by mosquito-proof mesh. Cracks in the tank and withdrawing of water using contaminated pots can contaminate stored water.

Storages should preferably be fitted with a mechanism such as a tap or outlet pipe that enables hygienic abstraction of water. Some households incorporate cartridge filters or other treatments at the point of consumption to ensure better quality of drinking-water and reduce health risk.





AIR HUJAN DAN KEKURANGAN AIR

• Population increase

• Industrialization

• Urbanization

(a) Increase in per capita utilization

(b) Less peculation area

• In places where rain fed/ irrigation based crops are cultivated through ground water

• Decrease in surface area of Lakes, talab, tanks etc.

What is a rainwater harvesting system?

A rainwater harvesting system basically collects rainwater and stores it for later use. All throughout history, this has been done but with the creation of mains water supply, this practice has all but died out in the western world.

Ireland is a country that is lucky enough to have a large amount of rainfall over any one year period. rainwater harvesting systems store rainwater and use it to supplement the uses of the non potable water.

How Can I harvest Rainwater?

There are quite a few different ways you can harvest rainwater.

The most popular way is the use of water barrels which can hold over 200 litres of water.

Many of these barrels have a tap built into the base of the water butt.

The next step would be to add a water pump. There are plenty on the market and the same water can be used for watering gardens, cleaning cars and patio areas etc. The beauty of water barrels is that they require very little maintenance apart from the occasional cleaning

MENGAPA KEKURANGAN AIR ?

• Deforestation

(i) Less precipitation

(ii) Absence of Barriers

(a) Rain drops checked by leaves of tree

(b) Water slowly descends through twigs & trunk

© Humus – acts as reservoir

(d) Tiny creatures – helps percolation

1 hectare of forest-6-7 Lac ton of water

(after filtering) top layer can hold 1.2 Lac tons of water

Sumber: Rain water harvesting, Gautam Banerjee, UP Jal Nigam

What is the solution ?

• Rain water is the ultimate source of fresh water

• Potential of rain to meet water demand is tremendous

• Rain water harvesting helps to overcome water scarcity

• To conserve ground water the aquifers must be recharged with rain water

• Rain water harvesting is the ultimate answer

Why Rain water be harvested

• To conserve & augment the storage of ground water

• To reduce water table depletion

• To improve the quality of ground water

• To arrest sea water intrusion in coastal areas

• To avoid flood & water stagnation in urban areas


What is rain water harvesting ?

1. It is the activity of direct collection of rain water

2. Rain water can be stored for direct use or can be recharged into the ground water aquifer

The roof catchment are selectively cleaner when compared to the ground level catchment

1.

Losses from roof catchment are minimum

2.

Built & Maintained by local communities

3.

No Chemical contamination & only required filtration

4.

Available at door step with least cost


The typical roof top rain water harvesting system comprises

• Roof catchment

• Gutters

• Down pipe & first flushing pipe

• Filter Unit

• Storage Tank

Roof catchment

The roof of the house is used as the catchment for collecting rain water. The style construction and material of the roof effect its suitability as a catchment, Roofs made of corrugated iron sheet , asbestos sheet, Tiles or Concrete can be utilized for harvesting the rain water


Gutters - Talang Air Hujan

Gutters are channels fixed to the edges of roof all around to collect & transport the rainwater from the roof. Gutters can be made in semi-circular and rectangular shape with cement pipe, plain galvanized iron sheet, PVC pipes, bamboos etc. Use of locally available material reduce the overall cost of the system.


Each rainwater harvesting system consists of at least the following components (INFONET-

BIOVISION 2010):

1. Rainfall

2. A catchment area or roof surface to collect rainwater.

3. Delivery systems (gutters) to transport the water from the roof or collection surface to the storage reservoir .

4. Storage reservoirs or tanks to store the water until it is used.

5. An extraction device (depending on the location of the tank - may be a tap, rope and bucket, or a pump (HATUM & WORM 2006); or a infiltration device in the case the collected water is used for well or groundwater recharge.

Diunduh dari: Sumber: http://www.sswm.info/category/implementation-tools/water-sources/hardware/precipitation-harvesting/rainwaterharvesting-r …………. 19/1/2013

Down Pipe

It is the pipe which carries the rainwater from the gutters to the filter & storage tank. Down pipe is joined with the gutters at one end & the other end is connected to the filter unit of the storage tank. PVC or GI pipe of 50mm to 75mm (2 to”) are commonly used for down pipe. Bamboo can be also used wherever available and possible


Rain Water Harvest Plant:

The water reaching the Roof through precipitation is allowed to flow down by an exhaust pipe which can be connected to a filter which further empties itself into the tube wells.

As a result of this small method we can recharge the groundwater and prevent the underground water table from further deterioration.

Diunduh dari: http://www.udaipurblog.com/save-water.html…………. 19/1/2013

First Flush Pipe

Debris, dust & dirt collect on the roof during non rainy periods when the first rain arrive.

A first flush system arrangement is made to avoid the entering unwanted material into the Filter media & storage tank. This is a simple manually operated arrangement or semi-automatic system with a valve below the ‘T’ junction


Roof materials and pipes

Some roofing materials are not suitable for rainwater collection-check with the manufacturer.

A typical rainwater system is set up to minimise contamination.

Diu8nduh dari Sumber: http://www.whakatane.govt.nz/Services/Water/Water-Usage/Collecting-and-using-rainwater/… 19/1/2013

Filter Unit

The filter unit is a container or chamber filled with filter media such as coarse sand, charcoal, coconut fiber, pebbles & gravels to remove the debris & dirt from water that enters the tank. The filter unit is placed over the storage tank or separately. It may be of Ferro cement filter unit, Aluminum, Cement rings or Plastic bucket etc.

Sumber: Rain water harvesting, Gautam Banerjee, UP Jal Nigam llustration of water flow scheme of a RTRWH system. Basic components: roof, gutters, first flush device (first rain separator), rain barrel with filter and tap and recharge well.

Source: RAINWATERCLUB (Editor) ( n .y.)

Diu8nduh dari Sumber: http://www.sswm.info/category/implementation-tools/water-sources/hardware/precipitation-harvesting/rainwaterharvesting-r … 19/1/2013

Storage Tank

It is used to store the water that is collected from the roof through filter. For small scale water storage plastic buckets, jerry cans, clay or cement jars, ceramic jars, drums may be used. For larger quantities of water, the system will require a bigger tank with cylindrical or rectangular or square in shape constructed with Ferro cement or cement rings or plain cement concrete or reinforced cement concrete or brick or stone etc. The storage tank is provided with a cover on the top to avoid the contamination of water from external sources .

The storage tank is provided with pipe fixtures at appropriate places to draw the water to clean the tank & to dispose of extra water. A provision for keeping the vessel to collect the water is to be made.


Schematic of a rainwater catchment and storage system.

Diu8nduh dari Sumber: http://www.nzdl.org/gsdlmod?e=d-00000-00---off-0fnl2.2--00-0----0-10-0---0---0direct-10---4-------0-1l--11-en-50---20-about---00-0-

1-00-0--4----0-0-11-10-0utfZz-8-00&cl=CL3.31&d=HASH3d2b712eafacff9c7fe5f7.4.1.1.1&gt=1 ………….. 19/1/2013

UKURAN TANKI PENYIMPAN AIR HUJAN

Ukuran tanki berdasarkan:

– No. of person in the House hold

– Per capita water requirement

– No. of days for which water is required.

Example

Drinking water requirement for a household with 5 family members, period 8 months & 6 lpcd

= 5x 180x 6 = 7200 Liters


The rainwater can be collected in pots at the edge of the roof or ideally from down-pipes connected to gutters. When it first starts to rain, debris from the top of the roof or gutters is washed into the downpipe, so it takes a while for clean water to filter through the system. A technique to remove this first flush of dirty water is by the use of down-pipe flaps.

When it starts to rain, the flap is closed and the water is directed away from the storage tank onto the ground . Once clean water can be collected, the down pipe flap can be opened and the clean water is diverted into a storage tank. Fitting sieves to the top of the down pipe further decreases the risk of dirt getting into the water.

Sumber: http://www.theinnovationdiaries.com/811/rainwater-harvesting-techniques/…… 19/1/2013

Air hujan yang tersedia dari cucuran atap bangunan

Annual rainfall (in mm) x roof area (in sq. m) x co-efficient of run off for roof co-efficient of run off

GI sheet

Asbestos

Tiled

Plaster on bricks/ Concrete

0.9

0.8

0.75

0.7

Water available from roof top 800 mm x 20 sq.m = 12800 Liters per annum


Air hujan yang tersedia dari

Size of Tank

cucuran atap bangunan

=1.2 m dia 1.8 m height

No. of Tanks 4

Volume of Tanks 3.14x1.2x1.2x1.5/4 2.03 cum 2000 liters

Volume of of 4 tanks = 4x2000 8000 Liters

(this can be designed as per requirement)

Schematic of a rainwater catchment system.

Diu8nduh dari Sumber: http://www.nzdl.org/gsdlmod?e=d-00000-00---off-0fnl2.2--00-0----0-10-0---0---0direct-10---4-------0-1l--11-en-50---20-about---00-0-

1-00-0--4----0-0-11-10-0utfZz-8-00&cl=CL3.31&d=HASH3d2b712eafacff9c7fe5f7.4.1.1.1&gt=1 ………….. 19/1/2013

Sistem Pemanen Air Hujan mempunyai tiga fase:

1) Mengumpulkan dan mengangkut air hujan

This is done through catchment areas & conduits. The catchment of a water harvesting system is the surface which receives rainfall directly. It can be a paved area like the terrace or courtyard of a building.

Conduits are the pipelines that carry rainwater from the catchment or rooftop to the harvesting system.

2) Filtrasi = Menyaring untuk membersihkan

In case of rooftop rainwater harvesting specially designed filters are used to filter the rainwater before it is stored in a storage tank for non-potable usage. PURE RAIN has the Purain range of

RWH filters for the same

For groundwater recharging, the rooftop or ground water needs to be properly filtered so that the water does not contaminate the underground aquifers. PURE RAIN has a specially design groundwater recharging system - Jal Rakshak that not only filters the water but also holds it while it percolates into the ground.

3) Menyimpan dalam tanki untuk dimanfaatkan / untuk mengisi groundwater

The harvested water can now be stored in storage tanks for immediate non-potable usage, which are designed according to your water requirements.

Existing non-potable water storage tanks in the society can also be used to store the harvested rainwater.

For groundwater recharging you need to design a collection chamber that holds the water while it percolates into the ground as the rate of percolation is much lower than the intensity at which it rains.

Diu8nduh dari Sumber: http://gibo13-purerain-primary.cluster2.hostgator.co.in/rainwater-harvesting ………….. 19/1/2013

MEMANEN AIR HUJAN.

Riomay

®

Renewable Energies has a range of rainwater harvesting products that provide versatile, economic and ecological solutions and give consumers the ability to freely collect water and use it without feeling guilty; on their plants and lawns, for washing their cars, in their washing machines and in their toilets.

Sumber: ….. http://www.riomay.com/renewable-technologies/rain-water-harvesting

Bagaimana meminimumkan problematik?

1 By providing pipe water system with source (electric based)

(a) Surface water

(b) Deep tubewells

2 Recharging stratas through rainwater harvesting methods

(No. of villages of lower range concentration can be decreased)

3 Storing rain water for drinking purpose

(a) In areas where electricity problem is more

(b) In areas where concentration is more

( c) In areas where PWS is uneconomical

(d) In areas where dependable source is not available


HASIL-HASIL

PENELITIAN

Rainwater harvesting for human consumption and livelihood improvement in rural Nepal: benefits and risks

Laia Domènech 1,* , Han Heijnen 2 , David Saurí

Water and Environment Journal. Volume 26, Issue 4, pages 465–472, December 2012

Use of rooftop rainwater as a source of drinking water in developing countries is increasing. However, scepticism about the potential of this source and the associated health risks is still prevalent among water planners. A free listing and a household survey among 120 households was conducted in the hills of Nepal to examine the performance of rainwater harvesting systems. Users perceive few health risks and in contrast, reported a wide range of benefits, including health benefits associated with the consumption of rainwater. Water quality testing results generally demonstrate good water quality but confirm that appropriate operation and maintenance practices are critical to ensure the collection of good quality water. Deficiencies in technical design and construction, lack of awareness, no market for spare parts and the inability of vulnerable households to maintain the system pose a risk to the collection and storage of safe water and to the long-lasting performance of the systems.

Diunduh dari: http://onlinelibrary.wiley.com/doi/10.1111/j.1747-6593.2011.00305.x/abstract ………… 18/1/2013

Cost-efficiency of rainwater harvesting strategies in dense Mediterranean neighbourhoods

R. Farreny , X. Gabarrell , J. Rieradevall

Resources, Conservation and Recycling. Volume 55, Issue 7 , May 2011, Pages 686–694

Rainwater harvesting (RWH) presents many benefits for urban sustainability and it is emerging as a key strategy in order to cope with water scarcity in cities. However, there is still a lack of knowledge regarding the most adequate scale in financial terms for RWH infrastructures particularly in dense areas. The aim of this research is to answer this question by analysing the cost-efficiency of several RWH strategies in urban environments. The research is based on a case study consisting of a neighbourhood of dense social housing (600 inhabitants/ha) with multi-storey buildings. The neighbourhood is located in the city of Granollers (Spain), which has a Mediterranean climate (average rainfall 650 mm/year). Four strategies are defined according to the spatial scale of implementation and the moment of

RWH infrastructure construction (building/neighbourhood scale and retrofit action vs. new construction). Two scenarios of water prices have been considered (current water prices and future increased water prices efficiency of these strategies, the necessary rainwater conveyance,




Methodology for the design of infrastructures and calculation of performance of indicators.

Diunduh dari: http://www.sciencedirect.com/science/article/pii/S0921344911000103………… 18/1/2013




NPV (Net Present Value) function depending on the pipe water price.

The minimum water price that entails positive NPV is shown.


Roof-harvested rainwater for potable purposes: Application of solar collector disinfection

(SOCO-DIS)

M.T. Amin , M.Y. Han

Water Research. Volume 43, Issue 20 , December 2009, Pages 5225–5235

The efficiency of solar disinfection (SODIS), recommended by the World Health Organization, has been determined for rainwater disinfection, and potential benefits and limitations discussed. The limitations of

SODIS have now been overcome by the use of solar collector disinfection (SOCO-DIS), for potential use of rainwater as a small-scale potable water supply, especially in developing countries. Rainwater samples collected from the underground storage tanks of a rooftop rainwater harvesting (RWH) system were exposed to different conditions of sunlight radiation in 2-L polyethylene terephthalate bottles in a solar collector with rectangular base and reflective open wings. Total and fecal coliforms were used, together with Escherichia coli and heterotrophic plate counts, as basic microbial and indicator organisms of water quality for disinfection efficiency evaluation. In the SOCO-DIS system, disinfection improved by 20–30% compared with the SODIS system, and rainwater was fully disinfected even under moderate weather conditions, due to the effects of concentrated sunlight radiation and the synergistic effects of thermal and optical inactivation.

The SOCO-DIS system was optimized based on the collector configuration and the reflective base: an inclined position led to an increased disinfection efficiency of 10–15%. Microbial inactivation increased by

10–20% simply by reducing the initial pH value of the rainwater to 5. High turbidities also affected the

SOCO-DIS system; the disinfection efficiency decreased by 10–15%, which indicated that rainwater needed to be filtered before treatment. The problem of microbial regrowth was significantly reduced in the SOCO-

DIS system compared with the SODIS system because of residual sunlight effects. Only total coliform regrowth was detected at higher turbidities. The SOCO-DIS system was ineffective only under poor weather conditions, when longer exposure times or other practical means of reducing the pH were required for the treatment of stored rainwater for potable purposes.



(SOCO-DIS)



Schematic diagram of Rooftop RWH system.



(SOCO-DIS)



Irradiance changes with exposure time under different weather conditions.



(SOCO-DIS)



Water temperature comparison between SODIS and SOCO-DIS system under different weather conditions.



(SOCO-DIS)



Microbial inactivation with different base surfaces of solar collector with low turbidity

(5NTU) and neutral pH values under moderate weather conditions.



(SOCO-DIS)



Microbial inactivation in SOCO-DIS system under different weather conditions with low turbidity (5NTU) and neutral pH values.



(SOCO-DIS)



Effects of different initial pH values on microbial inactivation with time for low turbidity (5NTU) rainwater under moderate weather conditions.



(SOCO-DIS)



Effects of different initial turbidity values on microbial inactivation with time for neutral pH rainwater under weak weather conditions.



(SOCO-DIS)



Microbial re-growths for different initial; (a) pH values under moderate sunlight with low turbidity (5NTU), and (b) turbidity values under weak sunlight with neutral pH.


.

Non-dimensional design parameters and performance assessment of rainwater harvesting systems

A. Palla , I. Gnecco , L.G. Lanza

Journal of Hydrology. Volume 401, Issues 1–2 , 20 April 2011, Pages 65–76

The use of non-dimensional parameters is proposed in this study to investigate optimum performance of rainwater harvesting systems. A suitable behavioral model is implemented to assess the inflow, outflow and change in storage volume of a rainwater harvesting system according to a daily mass balance equation under historical precipitation observations.

The model determines the water-saving efficiency, overflow ratio and detention time. These are interpreted as a measure of the system performance over the long-term simulation period. Performance is examined under various scenarios in terms of environmental conditions that are typical of the Italian territory (3 precipitation regimes and 3 levels of water demand) and system characteristics (10 storage capacity levels). Optimum sizing of the rainwater harvesting system is investigated as a function of two non-dimensional parameters: the demand fraction and the storage fraction. The demand fraction is shown to affect significantly the watersaving efficiency and overflow ratio, while the storage fraction controls the detention time thus influencing the water quality degradation within the system. Sensitivity analysis is carried out to investigate the influence of the length of the time series climate records on the reliability of the selected performance indices.

Results demonstrate that 30 years of daily rainfall records are sufficient to allow suitable assessment of the system performance. Optimum system design based on the medium demand fraction and the low storage fraction determines system performance that appears almost independent on the three precipitation regimes investigated.

Diunduh dari: http://www.sciencedirect.com/science/article/pii/S0022169411001144 ………… 18/1/2013

.




Configuration of the rainwater harvesting system used for the behavior analysis model. the inflow, V t the stored volume, Y t the rainwater supply, D t the water demand, M t

R t is the rainfall, Q t the main supply, O t the overflow, S the tank capacity and S min the minimum technical capacity.


.




. Mean values of monthly rainfall depth and the corresponding standard deviation values for the precipitation time series of Genoa, Florence and Catania.


.




Frequency distribution (fd) and the corresponding

Cumulative Frequency

Distribution (CFD) of the

Antecedent Dry Weather

Period (ADWP), the rainfall event depth ( H ) and duration

(dur) for the precipitation time series of Genoa,

Florence and Catania.


.




Total efficiency vs. the storage fraction for the precipitation time series of

Genoa, Florence and Catania with respect to three water demand fractions (high, medium and low).


.




Total overflow vs. the storage fraction for the precipitation time series of Genoa, Florence and

Catania with respect to three water demand fractions (high, medium and low).


.




The 50th, 75th and 90th percentiles of the detention time as a function of the storage fraction for Genoa

(gray dots), Florence

(white dots) and Catania

(black dots). Regression curves corresponding to the 50th, 75th and 90th percentiles are also reported. Note that detention time values correspond at the medium demand fraction scenario.


.

Silver disinfection of Pseudomonas aeruginosa and E. coli in rooftop harvested rainwater for potable purposes

M. Nawaz , M.Y. Han , Tschung-il Kim , U. Manzoor ,M.T. Amin

Science of The Total Environment. Volume 431 , 1 August 2012, Pages 20–25

Rainwater harvesting being an alternate source in water scarce areas is becoming a common practice. Catchment contact, however, deteriorates the quality of rainwater making it unfit for potable purposes.

To improve the quality of harvested rainwater, silver was used as antimicrobial agent in this study. Rainwater samples were taken from underground storage tank of a rooftop rainwater harvesting system installed in one of the buildings at Seoul National University, Seoul, South

Korea.

The target microorganisms (MOs) were Pseudomonas aerug inosa and Escherichia coli which were measured by using plate count method and standard MPN method, respectively. The efficiency of silver disinfection was evaluated at concentrations, ranging from 0.01 to 0.1 mg/l; the safe limit approved by WHO.

The experiments were performed for 168 h with different time intervals to evaluate the parameters including inactivation rate, residual effect of silver and re-growth in both MOs at lower (i.e. 0.01–0.04 mg/l) as well as the higher concentrations of silver (i.e. 0.08–0.1 mg/l).

Results showed the re-growth in both MOs was only in the case of lower concentrations of silver.

The possible reason of re-growth at these concentrations of silver may be the halting of bacterial cell replication process for some time without permanent damage.

The kinetics of this study suggest that higher inactivation and long term residual effect towards both MOs can be achieved with the application of silver at 0.08 mg/l or higher under safe limit.


.




Schematic diagram of RWH system at the campus.


.




Inactivation of P. aeruginosa at different concentrations of silver

(a) for the first 14 h, (b) re-growth at lower concentrations of silver after 14 h.

The inset of (b) is the same graph with zoomed y-axis to show the regrowth of P. aeruginosa .


.




Different modes of action of silver with bacterial cell.


.




Inactivation of E. coli at different concentrations of silver (a) for the first 24 h, (b) re-growth at lower concentrations of silver after 24 h. The inset of (b) is the same graph with zoomed y-axis to show the re-growth of E. coli .


.




. Graphical representation of (a)

P. aeruginosa

, (b)

E. coli

log inactivation with respect to time (experimental vs. calculated results).


.

The application of an analytical probabilistic model for estimating the rainfall–runoff reductions achieved using a rainwater harvesting system

Hyoungjun Kim , Mooyoung Han , Ju Young Lee

Science of The Total Environment. Volume 424 , 1 May 2012, Pages 213–218

Rainwater harvesting systems cannot only supplement on-site water needs, but also reduce water runoff and lessen downstream flooding.

In this study, an existing analytic model for estimating the runoff in urban areas is modified to provide a more economical and effective model that can be used for describing rainwater harvesting.

This model calculates the rainfall–runoff reduction by taking into account the catchment, storage tank, and infiltration facility of a water harvesting system; this calculation is based on the water balance equation, and the cumulative distribution, probability density, and average rainfall–runoff functions.

This model was applied to a water harvesting system at the Seoul National University in order to verify its practicality.

The derived model was useful for evaluating runoff reduction and for designing the storage tank capacity.


.




The schematic diagram of a rainwater harvesting system.





The schematic diagram illustrating the rainfall–runoff processes in a catchment.


.




Water flow in the storage tank.


.




Water flow in the infiltration system.


.




The effect of storage tank volume on rainfall–runoff reductions in a rainwater harvesting system.


.




The average runoff depending on the storage tank volume of a rainwater harvesting system.


.

Elemental composition at different points of the rainwater harvesting system

A.C. Morrow , R.H. Dunstan , P.J. Coombes

Science of The Total Environment. Volume 408, Issue 20 , 15 September 2010, Pages 4542–4548.

Entry of contaminants, such as metals and non-metals, into rainwater harvesting systems can occur directly from rainfall with contributions from collection surfaces, accumulated debris and leachate from storage systems, pipes and taps. Ten rainwater harvesting systems on the east coast of Australia were selected for sampling of roof runoff, storage systems and tap outlets to investigate the variations in rainwater composition as it moved throughout the system, and to identify potential points of contribution to elemental loads.

A total of 26 elements were screened at each site. Iron was the only element which was present in significantly higher concentrations in roof runoff samples compared with tank tap samples ( P < 0.05). At one case study site, results suggested that piping and tap material can contribute to contaminant loads of harvested rainwater. Increased loads of copper were observed in hot tap samples supplied by the rainwater harvesting system via copper piping and a storage hot water system ( P < 0.05). Similarly, zinc, lead, arsenic, strontium and molybdenum were significantly elevated in samples collected from a polyvinyl chloride pipe sampling point that does not supply household uses, compared with corresponding roof runoff samples

( P < 0.05). Elemental composition was also found to vary significantly between the tank tap and an internal cold tap at one of the sites investigated, with several elements fluctuating significantly between the two outlets of interest at this site, including potassium, zinc, manganese, barium, copper, vanadium, chromium and arsenic.

These results highlighted the variability in the elemental composition of collected rainwater between different study sites and between different sampling points. Atmospheric deposition was not a major contributor to the rainwater contaminant load at the sites tested. Piping materials, however, were shown to contribute significantly to the total elemental load at some locations.


.




Average (± SE) total contaminant load (μg/L) excluding sodium, potassium and magnesium, in roof runoff versus tank tap samples from Tanks A, B, C and D.


.




F

Diagram of RWHS collection points for Tank E. A: Roof runoff; B: Indoor cold tap supplied by tank water,

C: Indoor hot tap supplied by tank water, D: Sampling Point delivered via PVC pipe.


.




Average (± SE) total contaminant load (excluding sodium, potassium and magnesium) at site E, at different points of the rainwater harvesting system. Samples from the PVC pipe sampling point (D) contained significantly higher average loads than roof runoff samples (A) at this site ( P < 0.05).


.




. Average (± SE) total contaminant load in cold tap and tank tap samples (excluding sodium, potassium and magnesium).


.

Comparison of the microbiological and chemical characterization of harvested rainwater and reservoir water as alternative water resources

Ju Young Lee , Jung-Seok Yang , Mooyoung Han , Jaeyoung Choi.

Science of The Total Environment. Volume 408, Issue 4 , 15 January 2010, Pages 896–905

Rainwater harvesting (RWH) offers considerable potential as an alternative water supply. In this study, all of the harvested rainwater samples met the requirements for grey water but not for drinking water. In terms of microbiological parameters, total coliform (TC) and Escherichia coli

(EC) were measured in 91.6% and 72%, respectively, of harvested rainwater samples at levels exceeding the guidelines for drinking water, consistent with rainfall events.

In the case of the reservoir water samples, TC and EC were detected in 94.4% and 85.2%, respectively, of the samples at levels exceeding the guidelines for drinking water. Both indicators gradually increased in summer and fall. The highest median values of both TC and EC were detected during the fall.

Chemical parameters such as common anions and major cations as well as metal ions in harvested rainwater were within the acceptable ranges for drinking water. By contrast, Al shows a notable increase to over 200 μg L

− 1 in the spring due to the intense periodic dust storms that can pass over the Gobi Desert in northern China.

In terms of statistical analysis, the harvested rainwater quality showed that TC and EC exhibit high positive correlations with NO

3

−

(

ρ

TC

(

ρ

TC

= 0.786 and

ρ

EC

= − 0.688 and

ρ

EC

= 0.42) and PO

4

−

= − 0.484) and Na + (

ρ

TC

(

ρ

TC

= 0.646 and

ρ

EC

= 0.653), which originally derive from catchment contamination, but strong negative correlations with Cl

−

= − 0.469 and

ρ

= − 0.418), which originate from seawater.

.




Monthly variations in average rainfall volume and pH in the city of

Gangneung (2007–2008).


.




Box plots for pH and conductivity values of rainwater, harvested rainwater, and reservoir water samples. The significance is

α

= 0.05.


.




Box plots for the concentrations of major metal ions in rainwater, harvested rainwater, and reservoir water samples. The significance is

α

= 0.05.


.




Seasonal variations in terms of microbiological indicators for harvested rainwater and reservoir water samples. The significant is

α

= 0.05.


The effect of roofing material on the quality of harvested rainwater

Carolina B. Mendez a, J. Brandon Klenzendorf a,1, Brigit R. Afshar a,2, Mark T. Simmons b,

Michael E. Barrett a, Kerry A. Kinney a, Mary Jo Kirisits

Water Research 45 ( 2011 ) 2049 - 2059

Due to decreases in the availability and quality of traditional water resources, harvested rainwater is increasingly used for potable and non-potable purposes. In this study, we examined the effect of conventional roofing materials (i.e., asphalt fiberglass shingle, Galvalume metal, and concrete tile) and alternative roofing materials (i.e., cool and green) on the quality of harvested rainwater.

Results frompilot-scale and full-scale roofs demonstrated that rainwater harvested from any of these roofing materials would require treatment if the consumer wanted to meet United States Environmental Protection

Agency primary and secondary drinking water standards or non-potable water reuse guidelines; at a minimum, first-flush diversion, filtration, and disinfection are recommended.Metal roofs are commonly recommended for rainwater harvesting applications, and this study showed that rainwater harvested from metal roofs tends to have lower concentrations of fecal indicator bacteria as compared to other roofingmaterials.However, concrete tileandcool roofs producedharvested rainwater quality similar to that from the metal roofs, indicating that these roofing materials also are suitable for rainwater harvesting applications. Although the shingle and green roofs produced water quality comparable in many respects to that fromthe other roofingmaterials, their dissolved organic carbon concentrations were very high

(approximately one order of magnitude higher thanwhat is typical for afinisheddrinkingwater in theUnitedStates),which might lead to high concentrations of disinfection byproducts after chlorination.

Furthermore the concentrations of some metals (e.g., arsenic) in rainwater harvested from the green roof suggest that the quality of commercial growing media should be carefully examined if the harvested rainwater is being considered for domestic use. Hence, roofing material is an important consideration when designing a rainwater catchment.

Diunduh dari: http://nsf.kavi.com/apps/group_public/download.php/18211/Kirisits%202011%20roof.pdf ………… 18/1/2013




Water Research 45 ( 2011 ) 2049 - 2059

The type of roofing material used for the catchment can affect the quality of harvested rainwater.

Nicholson et al. (2009) compared harvested rainwater quality among six roof types: galvanized metal, cedar shake, asphalt shingle, two types of treated wood, and green (i.e., vegetated). The galvanized metal, asphalt shingle, and green roofs neutralized the acidic rainwater to a greater extent than did the other roofing materials. The treated woods yielded the highest copper concentrations (mg/L range), and the galvanized metal yielded the highest zinc concentrations (mg/L range), as compared to the mg/L concentrations of these metals from the other roofing materials.

Van Metre and Mahler (2003) found galvanized metal roofs to be a source of particulate zinc and cadmium and asphalt shingle roofs to be a source of particulate lead and potentially mercury.

Kingett Mitchell Ltd. (2003) found higher zinc concentrations in rainwater harvested from painted galvanized iron roofs that showed evidence of weathering as compared to those in excellent condition.

Despins et al. (2009) found that harvested rainwater quality from steel roofs was superior to that from asphalt shingle roofs, particularly with respect to turbidity, total organic carbon, and color.

1. Despins, C., Farahbakhsh, K., Leidl, C., 2009. Assessment of rainwater quality from rainwater harvesting systems in Ontario, Canada. Journal of Water Supply: Research and Technology-AQUA 58 (2), 117e134.

2. Kingett Mitchell Ltd., 2003. A Study of Roof Runoff Quality in Auckland New Zealand: Implications for Stormwater Management. Auckland

Regional Council, Auckland, New Zealand.

3. Nicholson, N., Clark, S.E., Long, B.V., Spicher, J., Steele,K.A., 2009. Rainwater harvesting for non-potable use in gardens: a comparison of runoff water quality fromgreen vs. traditional roofs. In: Proceedings of World Environmental andWater.

4. Van Metre, P.C., Mahler, B.J., 2003. The contribution of particles washed from rooftops to contaminant loading to urban streams.

Chemosphere 52 (10), 1727e1741.





Water Research 45 ( 2011 ) 2049 - 2059

Several types of chemical contaminants have been found in harvested rainwater including heavy metals (Fo rster, 1999; Lee et al., 2010), polycyclic aromatic hydrocarbons (PAHs) (Forster, 1998, 1999), pesticides

(Zobrist et al., 2000), and herbicides (Bucheli et al., 1998). Microorganisms also are present in roofrunoff, and fecal indicator bacteria and potentially pathogenic bacteria and protozoa have been detected (Ahmed et al., 2008).

1. Ahmed, W., Huygens, F., Goonetilleke, A., Gardner, T., 2008. Real-time PCR detection of pathogenic microorganisms in roof-harvested rainwater in southeast Queensland, Australia. Applied and Environmental Microbiology 74 (17), 5490-5496.

2. Bucheli, T.D., Mu¨ ller, S.R., Voegelin, A., Schwarzenbach, R.P., 1998. Bituminous roof sealing membranes as major sources of the herbicide

(R,S )-mecoprop in roof runoff waters: potential contamination of groundwater and surface waters. Environmental Science and Technology 32

(22), 3465-3471.

3. Forster, J., 1998. The influence of location and season on the concentrations of macroions and organic trace pollutants in roof runoff. Water

Science and Technology 38 (10), 83e90.

4. Forster, J., 1999. Variability of roof runoff quality. Water Science and Technology 39 (5), 137e144.

5. Lee, J.Y., Yang, J.S., Han, M., Choi, J., 2010. Comparison of the microbiological and chemical characterization of harvested rainwater and reservoir water as alternative water resources. Science of the Total Environment 408 (4), 896-905.

6. Zobrist, J., Mu¨ ller, S.R., Ammann, A., Bucheli, T.D., Mottier, V., Ochs, M., Schoenenberger, R., Eugster, J., Boller, M., 2000. Quality of roof runoff for groundwater infiltration. Water Research 34 (5), 1455-1462.





Water Research 45 ( 2011 ) 2049 - 2059

Schematic of the sampling device.





Water Research 45 ( 2011 ) 2049 - 2059

Average pH (panel A) and conductivity (panel B) for the pilot-scale events: ( ) Quality of the first-flush, ( )

Quality after the first-flush (average of tank 1 and tank 2), USEPA secondary drinking water standard range for pH (6.5e8.5), - - - Ambient sampler. One standard deviation is shown.





Water Research 45 ( 2011 ) 2049 - 2059

Average nitrate (panel A) and nitrite (panel B) concentrations for the pilot-scale events: ( ) Quality of the first-flush, ( ) Quality after the first-flush (average of tank 1 and tank 2), USEPA MCLs for nitrate (10 mg-

N/L) and nitrite (1 mg-N/L), - - - Ambient sampler. One standard deviation is shown.





Water Research 45 ( 2011 ) 2049 - 2059

Effect of antecedent dry days on average nitrate concentrations in first-flush samples from the pilot-scale roofs: dCd Shingle, dBd Metal, d;d Tile, d6d Cool, d-d Green, USEPA MCL for nitrate (10 mg-N/L).





Water Research 45 ( 2011 ) 2049 - 2059

Average DOC concentrations for the pilot-scale events: ( ) Quality of the first-flush, ( ) Quality after the first-flush (average of tank 1 and tank 2), - - - Ambient sampler. One standard deviation is shown.





Water Research 45 ( 2011 ) 2049 - 2059

Average total aluminum (panel A), arsenic (panel B), copper (panel C), iron (panel D), lead (panel E), and zinc (panel F) concentrations for the pilot-scale events: ( ) Quality of the first-flush, ( ) Quality after the firstflush (average of tank 1 and tank 2), USEPA primary or secondary drinking water standards or action levels: aluminum (200 mg/L), arsenic (10 mg/L), copper (1300 mg/L), iron (300 mg/L), lead (15 mg/L), and zinc

(5000 mg/L). - - - Ambient sampler. One standard deviation is shown.





Water Research 45 ( 2011 ) 2049 - 2059

Water quality parameters (minimumemaximum) of the rainwater harvested after the first-flush for the pilot-scale and full-scale roofs.


Soil water dynamics, growth of Dendrocalamus strictus and herbage productivity influenced by rainwater harvesting in Aravalli hills of Rajasthan

G. Singh

Forest Ecology and Management. Volume 258, Issue 11 , 10 November 2009, Pages 2519–2528

Degraded Aravalli hills in western India require rehabilitation through resource conservation and afforestation for meeting the biomass needs of resource-poor tribes of the region. Rainwater harvesting treatments i.e., control, Contour trench (CT), Gradonie (G), Box trench (BT) and V-ditch (VD) were prepared in <10%, 10–20% and >20% slopes categories and Dendrocalamus strictus L. seedlings were planted in

August 2005 with a view to conserve soil and water and increase the productivity of the hills. Soil water content (SWC), survival and height of D. strictus plants were highest ( P < 0.05) in <10% slope and all these variables decreased with increase in slope. SWC increased by 27.45% and 25.68% in <10% and >20% slopes, respectively than in 10–20% slope. From lowest in control SWC increased by 11.95%, 20.21%,

17.61% and 11.49% in CT, G, BT and VD treatments, respectively. Growth variables were highest in VD plots but the increase in shoot number was highest (2.9-fold) in CT plots. Increase in effects of rainwater harvesting with time indicated by a change in production pattern from highest ( P < 0.05) fresh and dry herbage in <10% slope in 2005 to 10–20% slope (24.66% and 26.09%) in 2006 and >20% slope (42.42% and

48.35%, respectively) in 2007. The increase in herbage was 1.17–2.40-fold in fresh and 1.20–2.52-fold in dry herbage over control. Highest ( P < 0.01) production was in V-ditch plots. The treatments order for herbage production was C < CT < G < BT < VD. But the production was highest in BT in <10% and in V-ditch plots in 10–20 and >20% slopes. Conclusively, soil water status is affected by natural slope, stony soil surface and rainwater harvesting structures influencing seedling growth and herbage production. Box trench and V-ditch enhanced surface soil water facilitating herbage growth, whereas contour trench facilitated deep soil water storage, which was made available to the plants after monsoon. Thus rainwater harvesting practices enhanced vegetation cover and productivity of the degraded hills and can be replicated to conserve soil resource and increase biomass for rural poor of the region.



G. Singh


Soil water dynamics influenced by natural slopes and rain water harvesting treatments in degraded hills of

Aravalli. C: control; CT: contour trench; G: gradonie; BT: box trench and VD: V-ditch. Error bars are ±SE of five replicate plots.



G. Singh


Growth pattern of height and number of shoots of D. strictus influenced by natural slopes and rain water harvesting treatments in degraded Aravalli hills. C: control; CT: contour trench; G: gradonie; BT: box trench and VD: V-ditch. Error bars are ±SE of five replicate plots.


Rainwater harvesting and greywater treatment systems for domesticapplication in Ireland

Zhe Li , Fergal Boyle, Anthony Reynolds

Desalination. Volume 260, Issues 1–3 , 30 September 2010, Pages 1–8

Water shortage has been recognised as one of the key issues facing many countries.

Fortunately, there are relatively abundant water resources available in Ireland because of its plenty of rainfall. However, Ireland will inevitably encounter water shortage in the future, especially in urban areas.

The water consumption per capita per day in Ireland is one of the highest in Europe.

The water demand is still increasing due to population growth and higher standard of living.

The use of domestic rainwater harvesting and greywater treatment systems has the potential to supply nearly 94% of domestic water in Irish households.

The utilisation of these systems can help Irish householders achieve significant water savings and avoid the domestic water bills that are due to be reintroduced. It also helps take pressure of the centralised water supply to meet the increasing water demand in

Ireland and eliminates issues such as high leakage during delivery and large treatment costs for domestic utilisation.

Domestic rainwater harvesting and greywater treatment systems can play a very important role in future water management and prospective sustainable living in




Average domestic water consumption per capita per day in selected EU countries in

2006 [4] .





A typical roof rainwater harvesting system in Ireland.





A typical domestic greywater treatment system in Ireland.


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Rainwater harvesting and management in rainfed agricultural systems in sub-Saharan

Africa – A review

Birhanu Biazin , Geert Sterk , Melesse Temesgen , Abdu Abdulkedir , Leo Stroosnijder

Physics and Chemistry of the Earth, Parts A/B/C. Volumes 47–48 , 2012, Pages 139–151

. Agricultural water scarcity in the predominantly rainfed agricultural system of sub-Saharan Africa (SSA) is more related to the variability of rainfall and excessive non-productive losses, than the total annual precipitation in the growing season. Less than 15% of the terrestrial precipitation takes the form of productive ‘green’ transpiration. Hence, rainwater harvesting and management (RWHM) technologies hold a significant potential for improving rainwater-use efficiency and sustaining rainfed agriculture in the region.

This paper outlines the various RWHM techniques being practiced in SSA, and reviews recent research results on the performance of selected practices. So far, micro-catchment and in situ rainwater harvesting techniques are more common than rainwater irrigation techniques from macro-catchment systems.

Depending on rainfall patterns and local soil characteristics, appropriate application of in situ and microcatchment techniques could improve the soil water content of the rooting zone by up to 30%. Up to sixfold crop yields have been obtained through combinations of rainwater harvesting and fertiliser use, as compared to traditional practices. Supplemental irrigation of rainfed agriculture through rainwater harvesting not only reduces the risk of total crop failure due to dry spells, but also substantially improves water and crop productivity. Depending on the type of crop and the seasonal rainfall pattern, the application of RWHM techniques makes net profits more possible, compared to the meagre profit or net loss of existing systems.

Implementation of rainwater harvesting may allow cereal-based smallholder farmers to shift to diversified crops, hence improving household food security, dietary status, and economic return. The much needed green revolution and adaptations to climate change in SSA should blend rainwater harvesting ideals with agronomic principles. More efforts are needed to improve the indigenous practices, and to disseminate best practices on a wider scale.

Diunduh dari: http://www.sciencedirect.com/science/article/pii/S147470651100235X ………… 18/1/2013

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Rainwater harvesting and management in rainfed agricultural systems in sub-Saharan

Africa – A review



. Typical designation of the micro-catchment rainwater harvesting systems.


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Rainwater harvesting and management in rainfed agricultural systems in sub-

Saharan Africa – A review



A typical designation of the macro-catchment rainwater harvesting systems (modified from Oweis et al. (2001)).


Micro-catchment water harvesting potential of an arid environment

Akhtar Ali , Attila Yazar , Atef Abdul Aal , Theib Oweis , Pierre Hayek

Agricultural Water Management. Volume 98, Issue 1 , 1 December 2010, Pages 96–104

. Micro-catchment water harvesting (MCWH) requires development of small structures across mild land slopes, which capture overland flow and store it in soil profile for subsequent plant uses. Water availability to plants depends on the micro-catchment runoff yield and water storage capacity of both the plant basin and the soil profile in the plant root zone. This study assessed the MCWH potential of a Mediterranean arid environment by using runoff micro-catchment and soil water balance approaches. Average annual rainfall and evapotranspiration of the studied environment were estimated as 111 and 1671 mm, respectively. This environment hardly supports vegetation without supplementary water. During the study period, the annual rain was 158 mm in year 2004/2005, 45 mm in year 2005/2006 and 127 mm in year 2006/2007. About 5000

MCWH basins were developed for shrub raising on a land slope between 2 and 5% by using three different techniques. Runoff at the outlets of 26 micro-catchments with catchment areas between 13 and 50 m 2 was measured. Also the runoff was indirectly assessed for another 40 micro-catchments by using soil water balance in the micro-catchments and the plant basins. Results show that runoff yield varied between 5 and

187 m 3 ha

−1 for various rainfall events. It was between 5 and 85% of the incidental rainfall with an average value of 30%.

The rainfall threshold for runoff generation was estimated about 4 mm. Overall; the soil water balance approach predicted 38–57% less water than micro-catchment runoff approach. This difference was due to the reason that the micro-catchment runoff approach accounted for entire event runoff in the tanks; thus showed a maximum water harvesting potential of the micro-catchments. Soil water balance approach estimated water storage in soil profile and did not incorporate water losses through spillage from plant basins and deep percolation. Therefore, this method depicted water storage capacity of the plant basins and the root zone soil profile. The different between maximum water harvesting potential and soil-water storage capacity is surplus runoff that can be better utilized through appropriate MCWH planning.





Typical layout of MCWH basin.





Definition sketch of water harvesting processes in a microcatchment.





(a) Annual runoff yield in relation to microcatchment area.

(b) Unit runoff yield in relation to microcatchment area.





Annual runoff to rainfall ratio for different micro-catchment areas.





Runoff yield in relation to event rainfall.





Predicted MCWH potential in relation to rainfall amount by using runoff micro-catchment and soil water balance approaches.
