Dear All,

The Dr. Behrouz Ahmadi-Nedushan`s CITY.

https://www.researchgate.net/profile/Behrouz_Ahmadi-Nedushan?_sg=aWyK0NtCNoOYNxEbf1GYhfMh6ZQJUhQJbUXe53zSL%2B9qZbWYhG77ZGwrh2ediDvJP6QVCf1fNPsUzYP6SWDzlA%3D%3D

GANAT Water Harvesting System behind the highest windward in the WORLD!

DOWLAT-ABAD Garden, Yazd Province, Yazd, Iran,

As elsewhere throughout the country’s high desert, water is delivered to the garden via GANATs.

A ganat,a Persian invention that began around 2000BC, is a deep well from which tunnels, some running as long as 25 miles contribute to a system of more than 100,000 miles of water delivery.

Attached Photo:

Captured by me:

9th National Conference on Watershed Management, Yazd, 30-31 Oct, 2013

Dear Golam, Very good topic in this era. Yes definitely harvesting rain water is being practice in hill areas, where there less source of drinking water. It is well in practice in many villages also. I think I have come across one project on this in the North Eastern hilly state of India. Rain water can be very good substitute in domestic uses as you mentioned. It may also be useful in Jhoom cultivation in hills. we can also use this as drinking water after certain treatment. More over, Collection of rainwater to be done in a place away from the pollution and which is more close to natural site. I think, Govt should take an initiative to conserve rainwater and make it available for domestic use.

Dear Soma,

Thank you and glad to know that rain water is being used in hill areas, villages and slash and burn agriculture in India

I guess it is proved beyond doubt that rainwater harvesting is good. I guess many countries have made it mandatory for new constructions to have rain water harvesting structures. But it being a reliable or significant source in urban areas as Golam has suggested will be very challanging. To cite an example a 1500 sq ft flat 15 - 20 stories as it is these days in NCR will help in collecting 75 m3 of water on average in NCR, India. How long 20 families can use it for over a year time?.

Apparently rainwater harvesting is used in many countries:

Currently in China and Brazil rooftop rainwater harvesting is being practiced for providing drinking water, domestic water, water for livestock, water for small irrigation and a way to replenish ground water levels. Gansu province in China and semi-arid north east Brazil have the largest rooftop rainwater harvesting projects ongoing.

In Bermuda, the law requires all new construction to include rainwater harvesting adequate for the residents.

Compulsory Rain water harvesting in Ireland and India

According to Independent Ireland (2 June 2014), all new buildings including houses, apartments, offices and schools in Ireland will be obliged to install rainwater harvesting systems to reduce consumption and help drive down utility bills. New buildings will be fitted with systems to divert rainwater from gullies into storage tanks, after which it is pumped through the plumbing system to reduce consumption of mains water. It will help reduce average household consumption by up to 50pc, leading to lower bills.

In few states in India, rainwater harvesting has been/ to be made compulsory for all new buildings (such as in Tamil Nadu, Kerala). Rainwater harvesting is also being promoted in hilly areas where it is difficult to pump water

Dear Golam,

I found the following website very useful containing information on water harvesting in different parts of the world with many nice videos and images.

http://www.harvestingrainwater.com/imagesvideoaudio/water-harvesting-video-and-audio/

@Golam et al. we have high rainfall in Malaysia. Actually river water is from rain water; and our tap water is recycled from such water. But individually, we can collect some rain water. I use it for washing floors etc. However our roofs are not flat. So we lose quite a lot of this resource. Sad, agree?

Dear Golam,

Rainwater is a sustainable resource everywhere. Certainly, it should be used in each country even rainwater should be used as important water supply in each household. As far as I know the attention in Hungary does not focus on it.

Dear Miranda,

Yes I do know Malaysia receives > 2000 mm annually, at least it is a good practice that you use rainwater for washing floors (saves some precious resource on earth)

Dear Andras,

Rainwater will save your water bills as well reduce pressure on town water supplies

Despite the limited data on quality, domestic rainwater harvesting, as a source of water supply, has been a common practice in most regions of Cameroon due to limited public water supply schemes and high demand. Few recent studies in the country have shown that the quality of rainwater is suitable for human consumption. Thus, future and large scale rainwater harvesting in Cameroon can help augment water supply schemes.

Dear Mengnjo,

Thank you for informing that rainwater harvesting is a common practice in most regions of Cameroon and should be expanded!

Golam to me it still looks that a very small quantity can be harvested in urban areas. The other issue will be of quality, the roofs have dust etc, which will be washed with the rainwater. underground storage will lead to bacteria/virus buildup. Its drinking water usage is not very advisable.

Dear Golam

I am not familiar with it though I know some start is made in India in some parts where the water scarcity is a problem. You can see the details in the National Geographic coverage here.

http://environment.nationalgeographic.com/environment/freshwater/l/lessons-from-the-field-rainwater-harvesting-in-hiware-bazaar--india/

In Japan it is done much wider. A good coverage of Japanese water harvesting is presented here.

Can make rainwater permanent source of water use and take good if one of the proposals is to provide areas to absorb and store rain water and treat it to be safe to drink as that rain water can also be used in agriculture, especially in the desert areas.

Dear Saif et al

Rainwater harvested can be used directly for landscape irrigation, garden ponds, and most exterior applications. However, for use in buildings, supplemental filtration will be essential and disinfection is highly recommended. For toilet flushing and clotheswashing, a sediment filter will remove suspended solids which can clog and damage valves, and an activated-carbon filter will remove dissolved organic matter which can cause discoloration and odours.

It is not generally recommended for direct drinking

Dear Nageswara,

many thanks for the two important links. I had a quick read the summary of which are as follows;

Japan: In Japan Rainwater harvesting is promoted as an alternative water resources, preventing urban flooding and securing emergency water for disaster-responses. Currently more than 60 municipalities subsidize the installation of rainwater tanks, while more than 45 municipalities subsidize the conversion of old septic tank to the rainwater storage tank for flood control

India: Over 85 percent of the cultivated area in India is either directly dependent on rain or depends on rain to recharge its groundwater. Seasonal rain provides water for irrigation, drinking, and household needs. It provides water to livestock and is necessary to grow fodder for animals.

@Golam, I am aware of the water importance in both ways, floods as well as water shortage! In Montenegro,the former Yugoslav republic, I spent some time every year at Adriatic see. A lot of these days are without water. It kills tourist potentials of this country. In Montenegro as well as in Serbia, there is no strategy for use of rainwater as sustainable source!!! There are just individual attempts storage of rainwater, but not systematic solutions!

"A number of measures exist that may potentially reduce the use of publicly supplied water. These can be broadly grouped into the categories of water saving devices; greywater re-use; RAINWATER harvesting and the efficient use of water in gardens and parks; leakage reduction; behavioural change through raising awareness; water pricing; and metering. Since treating, pumping and heating water consumes significant amounts of energy, using less publicly supplied water also reduces energy consumption"! This is a part of fresh water research in Montenegro, but there are facts for every country, for Serbia also!

http://www.climateadaptation.eu/montenegro/fresh-water-resources/

Very important topic. I Propose to set up a low-cost water projects, projects of desert dams and ponds to collect rain water and floods for use in the provision of water for watering livestock , and meet the minimum requirements in the agricultural hinterland Statistics has shown that about ninety percent of the rain water in Jordan, for example, which falls every year in vain and can not take advantage of them , and that many of the plans have been developed to establish dams desert , was chosen twenty sites including ponds ancient desert , which provides thousands of cubic meters of water because the citizen's life in the Jordanian desert and the desert , villages and rural areas lies in securing water for watering livestock , which is the main source of income for tens of thousands of Jordanian families .

The government succeeded in establishing a large dams such as the King Talal Dam and Arab's Dam, so that the amount of water stored in these dams is increasing about the " 70 " million cubic meters and most of the rain this winter , and that these quantities of water will contribute to the Dam is part of the projected deficit in the water during the summer for irrigation in the Jordan Valley and other areas .

Experts contend that the cost of desert dams and ponds are almost limited compared with many benefits, particularly the achievement of water security in remote areas , but the obstacles are still placed in front of the implementation of these projects despite the fact that government encouraged mobilizing tools , engineers for these projects in order to reduce cost .

Dear Jenan, You have explained professionally the need for rainwater storage as one of the measures for water security (livestock, remote rural areas, livelihoods), in a low rainfall country such as Jordan. Harvesting rain water via dams is one of the most important climate change adaptation strategy, however environmental impacts should be assessed prior to dams planning and development

Dear Kamal,

No rain no life, a very intelligent way of expressing the significance of rainwater in Jordan!

Dear Ljubomir,

Many thanks for the info (water shortage due to low rainfall and impacts on tourism) and the links related to Montenegro. Climate change is projected that there will be less rainfall in Southern Europe. However public awareness on smart use of town water, harvesting rainwater will save both water bills and energy consumption and reduce emissions of greenhouse gases!

Dear Prof Kamal and friends, I wish we can send lots of water to you!

Here is 1 incident that I can share. I have a church friend who often calls up our Water Department to report leaks in public pipes and taps. He received a letter last year thanking him, and asking him to attend a lucky draw on a Saturday. Saturdays are our busy days of housework and running errands. So he arrived, and was the last person to pick his draw. He thought he would get the prize nobody wanted (perhaps the hair dryer); and everyone was eyeing the 43 inch plasma TV. To his great surprise, he won the TV.

Dear Golam,

Thanks for inviting me to answer the relevance of rainwater harvesting in my country. Off-course, in India, rain water harvesting is one of the major tools for water resource management. India is a diverse country in terms of availability and use pattern of water. There is plenty of water and at the same time, severe scarcity of water prevail many parts of India. The western part is characterized by arid climate, where throughout the year, water scarcity prevails. The northern plain has excess water while in the southern peninsula, water is most scars. The Himalayan region is the home for major perennial river systems i.e. the Ganges system, the Brahmaputra system and the Sind system, but the people living in this area observe severe water scarcity. Meanwhile, the largest parts India receive rainwater during the three months of Monsoon season and that water is mostly run-off. The other months of the year remain dry. It is therefore, harvesting of rainwater through various means such as roof-water harvesting by individual household, and from the community level, construction of small check dams, construction of ponds, field budding and etc. to store the monsoon rain and supply it during the dry season, indeed will be a milestone in the field of water conservation, particularly a country like ours where the above-said situation of plenty and scarcity prevails. However, rain water harvesting is essential for every country, which is characterized by scarcity of water.

Dear Vishwambhar,

Many thanks for an excellent overview about the current status of water resources in India. It is mixed with dry arid climate in the south where there is water scarcity, while in the north there is an excess water.People living in the Ganges system, the Brahmaputra system and the Sind system observed severe water scarcity, perhaps related to the melting & receding of the Himalayan glaciers. Such shortages, i.e. river flows will have severe consequences on irrigation, agriculture, aquatic biodiversity for example. Rainwater harvesting as you suggested at the rural community level would be much beneficial, as I understand in some parts of India groundwater is contaminated with arsenic (e.g. West Bengal, Bihar, Assam, Uttar Pradesh) and surface water is heavily contaminated with chemicals and microbial pathogens

Odisha proposes to harvest rain water. The new scheme under which total 16,955 buildings will be covered proposed to completed by 2019. The subsidy will be limited 50% of the actual investment. The Hindu,Bhubaneswar, May 13,2014.

Dear Lala,

An important statistic about Odisha. I came to know that rainwater harvesting has been made compulsory for all new buildings in Tamil Nadu, Kerala

@Golam, it happens that Kerala in South India is where Lijo was born and grew up. For Environment Day, he has sent some of us this pic of Atharapilly waterfall, so I share it with friends on this thread, the beauty of water. Without rainwater harvesting, rain goes inside this waterfall and rivers naturally...

Dear Kamal,

Glad to know that you have asked to introduce mandatory water harvesting at your Hashemite University buildings

Thanks for requesting me to answer the relevance of rainwater harvesting in my country.

In Sri Lanka, annual rainfall is 2500 to 5800 mm in south west and about 1250mm in the other parts of the island. Sri Lanka is blessed with two monsoons, namely the South-West from May to September, and the North-East from December to February. Rainfall during the monsoon is more than enough to provide the water needs if properly collected. However, the effects of extreme climatic changes of natural phenomena are being affected the seasonal rainfall patter in Sri Lanka. In fact, in the dry zones of the island (three quarters of area of the island) people suffer from long drought periods with dried-up wells and no natural sources for water. In most of the cities, people have treated pipe-borne tap water, therefore the majority of the households find no reasons for installing a rainwater harvesting system. However, awareness raising in Sri Lanka is necessary on harvesting and effective utilization of rainwater as a solution for a sustainable water management that will lead to economic and environmental benefits.

Rain water harvesting in rural area has been practiced throughout the history by collecting water in tanks. There are projects which are implementing in dry rural areas that are in the most emergent need of water. Today more than 31,000 rain water harvesting systems are in operation throughout the country most of them in rural areas where the most emergent need of water. In the rural areas, rain water is used for agriculture and various other purposes.

Dear Golam

The stored rainwater is independent of any centralized system and thus can promote self-sufficiency and contribute to fostering a greater appreciation for this precious and essential resource. The stored rainwater means not only water conservation,but energy saving . Collecting rainwater also helps to minimize local and floods caused by runoff from impervious surfaces and rooftops erosion because of this collected water is stored

Rainwater is one of the purest sources of water available. The quality of rainwater is a great incentive for people who choose the rain as their primary source of water. The quality of rainwater often exceeds the quality of groundwater and surface water: it is not in contact with the soil that can be a source of various pollutants that are often dumped into surface waters and can contaminate groundwater. However, the quality of rainwater can be influenced by where it falls, because localized industrial air emissions may affect its purity

Dear Nirmala,

Many thanks for providing an excellent overview of water resources situation in Sri Lanka. It looks you have both high (south) and low rain fall (north). Contrary to other countries, you are in a better situation with regard to water resources. But still water savings in the context of green house gas emissions (treated water requires very high energy consumption) still be an awareness approach. I read some reports related to Sri Lanka where (probably in Jaffna) surface water found to be contaminated with high risk chemicals, there rainwater may be important! Despite all as you informed that 31,000 rain water harvesting systems supporting the rural people is indeed a show case the beneficial aspects of rainwater harvesting

Dear Nelson,

Thank you for providing an insight about rainwater. I do agree that in some circumstances the quality of rainwater often exceeds the quality of groundwater and surface water, best example is in the Indian subcontinent where groundwater is contaminated with arsenic and surface water with both domestic and industrials effluents

Both the Govt. & the effected communities have taken some steps in India to address the problem.

Govt. now seriously thinks to connect all the rivers in India,so that excess of water can be supplied to needy regions - but this will take time.Gujarat state in Western India has constructed numerous man made ponds,& check dams along the water way,to make available water to villages. It has constructed huge canals all along the coastal belt where there is salinity ingress problem,by this way,fresh water is now available to far flung rural coastal areas.Districts like Surat,Nadiad & Anand has a good net work of water canals, so that all the ponds & lakes in these districts are now perennial. Excess water from Narmada river has been diverted through canals laid in all arid districts of the state. The same river water has also been diverted through the Sabarmati river,which used to get dry during summer months.

Central Govt. had also constructed the Indira Canal harnessing water from the Sutlej River in Punjab right through the three most arid districts of India, i.e.Ganga Nagar, Bikaner & Jaisalmer of Western Rajasthan State of India.

Community level:

Now there is good public awareness to recharge the ground water through rain water, & this helps bring up the water table & assures year round supply of ground water, when needed.In past decades, individuals have constructed underground water storage very huge tanks, right below their own house, to store rain water, which assured potable water through the year. By this way, they are self sufficient.

When I was working in a rural coastal place, where there was scarcity of potable water, we used to make distilled water from sea water with the help of 1 sq. meter solar distillation units which were covered with glass.Each one of them yielded about 7 to 10 liters/day.

In short, It's possible to be self sufficient in water,provided humans has the will to overcome the problem.

Dear Chandravadan,

Thank you for your inputs. I have gathered there has been significant effort to store rain water via constructing ponds and small dams, underground storage tanks, recharging groundwater to augment freshwater reserve in arid part of India. Many thanks again

Rain water harvesting in Bolivia

• Precipitation range in Bolivia is zero to 7000 mm/year

• In rural areas rainwater is always an important resource

• In some dry places in the Andes, water is even harvested using nets that collect morning fog

• In the Amazon, during the last flooding/inundations many people depended on rainwater for consumption, since all other sources (wells, streams, etc.) were flooded and contaminated

• Many people still puts buckets under the roof every time the rains start pouring

(an answer from Vincent Antoine Vos- a Dutch researcher who is currently living and working in the Bolivian Amazon sent to me directly)

Rainwater can be a sustainable resource in Zimbabwe. We already rely heavily on rain-fed agriculture and if the rainwater can be harvested and stored can be used for irrigation during the dry months as well as for urban water use such as flushing. In think for us the issue of harvesting at household level it is what needs to be intensified.

Dear Annatoria,

It looks Zimbabwes agriculture is primarily depends on rain, in fact, about 90% agriculture in sub-Saharan Africa is rain-fed. I understand few farmers in south Matebeleland is already harvesting rainwater and there has already been an association entitled ‘Rainwater Harvesting Association of Zimbabwe’?

In all countries of the world there has been a big water, but it can cause great damage if it turned out to Seoul to take on the way each faced so must for researchers and governments to find a way to exploit the rain water and thereby eliminate the risk of flooding at the same time take advantage of the water as we do so we spend Ali drought, which affects some regions of the world.

As the driest inhabited continent, Australia is very dependent upon rain water. Most places depend upon that. Town water supplies use rainfall, stored in larger dams. Most rural residents have tanks. In some towns and cities any new house has to have a small tank, often used for gardens, washing etc. There is still a problem that some people insist on having excess water for silly things like roses. Elsewhere native gardens are preferred. Agriculture does require a lot of water though to maintain food supply. Forty years ago there was a CSIRO report suggesting Australia's population limit was 25m people, constrained by water supplies & where people live. We could handle more, though it does make a mess of the landscape, by desalination plants (there are some already) and very expensive pipelines from areas with higher rainfall. Unfortunately Governments are only partially serious about better management of water.

Dear Ahmed,

Egypt is one of the water stressed countries and has limited water resources. Therefore exploitation of rainwater would be vital for agriculture and other domestic purposes (drinking). Furthermore development of sustainable catchments at appropriate locations may also be needed

Dear David,

Thank you for your valuable inputs. I do agree with you being the driest continent, Australia depends on rainwater for irrigation, rain fed agriculture and other beneficial purposes including town supply. It is alarming since most of the southern and eastern Australia (major food growing regions) will be impacted due to projected reduced in rainfall. Perhaps you are also aware that the annual stream flow in the Murray-Darling basin (Australia) is projected to fall (e.g. by 10-25% by 2050) which would have severe consequences on irrigated agriculture in the region.However, there have been some initiatives to save waters via irrigation channel automation, more accurate metering and irrigation channel lining (plastic and clay lining) and hope these measures will help!

Tamara V. Tulaikova, a senior researcher with the Russian Academy of Sciences sent a message direct to me about this topic

Rain-water is an additional water resource

She (Tamara V. Tulaikova) would like to coordinates with scientists in Australia to perform experiments with clouds to stimulate the rains

Scientists are testing laser beam which could control weather and stimulate rain and lightning. The new method could help increasingly drought-stricken areas around the The scientists at the University of Central Florida’s College and Optics & Photonics and the University of Arizona are working on a new way to point a high-energy laser beam into a cloud to stimulate rain and lightning. Demetrios Christodoulides, a professor collaborating with graduate students, said: “This work could ultimately lead to ultra-long optically induced filaments or plasma channels that are otherwise impossible to establish under normal conditions. In principle. such dressed filaments could propagate for more than 50 meters or so, thus enabling a number of applications. This family of optical filaments may one day be used to selectively guide microwave signals along very long plasma channels, perhaps for hundreds of meters.”http://hotwire.platfuse.com/tech/laser-beams-can-control-weather-stimulate-rain/

Dear Lala

Many thanks for the links and an important innovative research (laser beam) to stimulate rain; much needed for drought stricken countries.

Dear Wayne,

Your situation (north Australia) is different from major part of Australia (South East-Sydney, Melbourne, Adelaide and Perth where bulk of populations resides and much water stressed). However still if you use rainwater for your garden that is savings, not only in terms of money (which could be minimal) but you also helped in reducing energy use and greenhouse gas emissions. Everyone’s contribution counts! Awareness and education would be vital. See some links of ‘The Rainwater Harvesting Association of Australia (RHAA)’ which suggested an increase in consumer awareness of water and energy conservation through using alternative sources such as rainwater, greywater, and recycled water for Australia

http://www.rainwaterharvesting.org.au/

http://www.rainwaterharvesting.org.au/publications

Dear Golam Kibria,

In Sri Lanka, rainwater is being harvested from long (it dates back to 4th centry BC). Please refer http://en.wikipedia.org/wiki/Ancient_constructions_of_Sri_Lanka for general information. The rainwater harvesting was done into man made tanks or reservoirs which are in a cascade tank system. Please refer http://www.gsslweb.org/home/files/14-29-34.pdf. These systems are still functional and thousands of hectares are irrigated under these water harvesting systems. Therefore, rainwater harvesting is sustainable.

Rainwater harvesting provides an independent water supply during regional water restrictions and in developed countries is often used to supplement the main supply.

It provides water when there is a drought, can help mitigate flooding of low-lying areas, and reduces demand on wells which may enable ground water levels to be sustained.

It also helps in the availability of potable water as rainwater is substantially free of salinity and other salts, especially in arid and semi-arid regions.

Given the importance of water in dry regions, it became the third international conference of the Rainwater Catchment Systems that will be held on 18 and 19 February, 2015 in the University of Birjand, Iran.

http://www.iscconferences.ir/635/en/

Dear Najim,

Many thanks for the two weblinks. The Tank Cascade Systems (TCS)’ to harvest rainwater to support irrigation (paddies) in dry zone in Sri Lanka is of unique in the context of ancient technology. I am pleased that this ancient technology (TCS) is still functional and applied!

Dear Behrouz,

Thank you for the notification related to forthcoming ‘International conference of the Rainwater Catchment Systems’ which highlights the importance of rainwater and the topic we are currently discussing in this session!

“Let not a single drop of water that falls from the skies flow to the sea, without being used for the benefit of man”

King Parakramabahu the Great- Sri Lanka (1153-1186 A.D)

Potential of rainwater in Chile

(Javier Lira, Pontifical Catholic University of Chile, Departamento de Economía Agraria sent an answer direct to me on this topic)

In Chile, more than half the country has large amount of rainfall, which can be used for domestic, irrigation consumption in rainfed crops, etc. Another fact, more than 70% of the fresh water in Chile, from the Andes meets the sea at the same season and can be stored in dams. There are areas of southern Chile, mostly rural, that are supplied independently of rainwater. These areas do not have the infrastructure to make efficient use of the resource.

In short, in places where the water resource is available in large quantity, there is no incentive to use, efficient and productive consumption

In my country, Sudan the rainwater widely used in harvesting.

Dear Sara,

Thank you. I came to know that in Northern Darfur, farmers and livestock keepers construct ‘hafirs’ in low lying areas to capture/to store rainwater?

Sri Lanka has a national policy on rain water harvesting since 2005. Legislation which followed has made rain water harvesting mandatory in all new buildings above a certain roof area in Municipal and urban areas since 2009. Although most city households has pipe water supply as stated by earlier writer, this covers only 42% of the population, others who live in rural areas has to rely on other sources such as dug wells, tube wells ect. In some parts of the island specially in the North Central, Northern and North western province there are reports of increased Chronic Kidney Disease of un know etiology. All though the cause is not identified yet ( thus unknown etiology), drinking water contaminated with excessive use of agriculture fertilizers and pesticides is thought to be one of the causative factor. Rain water harvesting is ideal solution for this problem without going in for expensive and unsustainable treatment systems. Since rain water does not contain any of these toxic chemicals. More details of rain water harvesting in Sri Lanka policy legislation can be viewed at www.lankarainwater.org

Dear Tanuja,

Thank you for your valuable inputs in particular identifying agriculture fertilizers and pesticides as one of the contaminants in surface waters in Sri Lanka. Pesticides, herbicides and trace metals are also one of the most frequently detected chemicals in Australian surface as well as groundwater’s!. Yes, rainwater is always preferred (traditionally) in rural areas in developing countries where there is lacking of town supply, in particular rainwater harvesting prevents women in developing countries not to travel much distances to fetch for water. In recent time, rainwater harvesting has been identified as one of the useful tool for developing countries in advancing their attainment of the Millennium Development Goals on water, sanitation and poverty alleviation and gender equality!

Yes, but at the same time we should all start investing in desalinization technology / infrustructures since precipitation paterens are getting harder and harder to rely on.

Dear Jonathan,

Yes, Climate change projected that rainfalls would be much reduced in some regions such as Sub-Saharan Africa, South Eastern Australia, and Southern Europe. Poor countries may not be able to afford a desalination plant (could be very expensive)!

Thank you for inviting me to comment on your question.

If I were involved in managing an arid country to combat the impacts of global warming and at the same time making an effort to increase the natural rainfall, instead of collecting rainfall from roofs, I would put a government-provided solar panel on every single roof in the country.

Then I would set aside large areas as Ecological Restoration Preserves that are currently deserts, and replant the original native perennial grasslands, to increase the rainfall of the area. And if any of those desert areas produce airborne dust, work on those areas first.

Today in California we are experiencing the worst drought in 400 years, and there is zero rainfall to harvest, and our problems stem from at least seven issues,

1.) The airborne dust getting into the atmosphere from China dissipating the rain clouds before they ever get to us. You can see a movie of the Dust Cloud coming to us from China at http://www.ecoseeds.com/dust.gif . Unfortunately climate and rainfall computer models have not yet added atmospheric dust to their calculations, and are still stuck in the El Nino, La Nina models, but my observations indicate that atmospheric dust is the most powerful climate modifier, able to eat Category-5 cyclones for breakfast, like GONU at http://www.ecoseeds.com/newGONU.html.

2.) We have converted all of our perennial grasslands to annual weed patches, so that instead of conserving the soil moisture in summer like the natives did, the annuals suck out all of the soil moisture to produce their seeds in spring, drying out the soil.

3.) Added our exotic grazing animals as the same biomass weight as the 38 million humans, in most places creating barren soil in the summer from grazing the annuals to the ground, and the bare soil heating the air warmer than it would be if it had vegetation on it, like my picture at http://www.ecoseeds.com/cool.html.

4.) Dammed every river, pumping every aquifer, and got rid of the wetlands that kept moisture in the soil year round.

5.) Global warming changing the dew point, making it more difficult for clouds to form, and normally we would have some measurable dew fall even in summer which sustained the native plants like the redwood trees, but with the change in dewpoint, that important source of moisture is gone.

6.) The interplay between natural vegetation and rainfall or the lack vegetation and the lack of rainfall, is clearly played out each year in the mountains above Salalah in the Sultanate of Oman, that you can see at http://www.ecoseeds.com/salalah.html. Where there is vegetation, there is rainfall each summer. Where there is no vegetation, you have deserts for thousands of miles.

7.) The interplay between native vegetation and the cloud forming Pseudomonas syringae bacteria that live on that vegetation, need a closer look.

My conclusion is that in order to have adequate rainfall so humans can live in arid and semi-arid places, we may need to have large scale ecological restoration of the surrounding wild lands that provide that rainfall for that area each year.

When we have to do things like harvest rooftop rain or build desal plants, that should be a sign that we have allow our natural surroundings to get in a very bad condition, that human life is on the edge of survival in those areas.

The major issue that permanently ends civilizations, is long term droughts.

We may need to admit to ourselves, we will need to abandon certain areas--while at the same time start the process of ecological restoration of these areas so they can be reoccupied at some time in the distant future. And we may need to abandon key currently farmed wetlands and permanently convert them back to wetlands, and break dams, and lower grazing to perhaps as low as 5% of previous densities, to allow the native ecosystems to recover.

It is difficult to go from hoping that harvesting rooftop rainfall will save us, to get our minds around the scale of the problem. But when you are in the situation that 38 million people in California are in right now, of NO rainfall to harvest, we need to look at the big picture to see what needs to be done so we can continue to live in certain places into the future.

When the water pressure in a California water system drops below 15 pounds per square inch for example, you legally cannot stay there--like the people from Oklahoma in the 1930s, you must go where there is still some rain falling.

Dear Craig,

Thank you for your long discussion, noted about the worst drought in 400 yrs in California and suggestions that replantation (ecological restoration) of native perennial grasslands may increase the rainfall to occur. This is an important observation (based on your weblinks http://www.ecoseeds.com/salalah.html) that where there is vegetation, there is rainfall and where there is no vegetation, there is no rainfall (case study with the mountains around Salalah, the Sultanate of Oman)

Every little rain counts as per paper in press attached

Dear David,

Thank you for your galley proof paper (Water Quality Assessment in Parts of the Niger Delta Region of Nigeria Part II), which showed that community water quality including rain water in the Niger Delta region is safe and within the recommended guidelines for drinking water, and other beneficial usages (livestock, recreational and irrigation).

I had a quick read and according to your paper the microbial pathogens (Escherichia coli and total coliforms) and physicochemical (pH, calcium. sodium, chloride, nitrate, sulphate and bicarbonate) are within the international guidelines.

From the results it looks that you donot have much agricultural activities in the region and water is not contaminated by sewerage wastes for example. I presume people use rainwater in the studied area for drinking purposes as well?

The drinking, irrigation, recreation and livestock WQ fall under fair category (out of excellent, good, fair and marginal category compared to Canadian WQ index for water supply) which is a good news for the communities I feel!

Frank Frank Veroustraete , University of Antwerp · Department of Bioscience Engineering, Belgium sent an answer direct to me, the summary of which is as follows:

I guess when you have about 300 to 500 mm of rainfall annually, rainwater is a sustainable resource for the apps you have so completely mentioned. I collect rainwater of the green roof of my city dwelling. In my country we have about 900 mm of precipitation (rain and snow) annually). I have enough rainwater collected underground (6m³) to flush the toilet, to wash clothes, to clean the street and to irrigate a small garden when it becomes to dry during summer.

Very useful question to answer as well as to create awareness about rainwater. Definitely, rainwater can be a a sustainable resource for electricity generation, agriculture and fishery industry etc. But the dilemma is to preserve this precious natural resource, effective strategies are not well implemented in a sustainable manner. Consequently, rainwater loss of lives and properties every year.

Good observation dear @Asmat. Rainwater MUST be a sustainable resource all over the world!

Thanks for compliments, respected @Ljubomir Jacić.

we need a mass awareness camp to sustainable use and conservation of rain water. It should broadcast in every national news channels, Radio specially for remote villages, news papers and in several other media. There is a need of sensitization activity by the Government and strong execution of the plans.

Dear Soma,

Rainwater harvesting is being promoted in many countries!

Dear Golam, Yes it is done in many countries. active promotion and regular practice is must to observe in this case.

Dear Golam ,

As everyone I also agree that rainwater harvesting should promoted all the over the world, especially with water scarcity problem which will be very serious problem in the future. It is interesting there are also ancient ways of rainwater harvesting. One of them is Qanat.

A qanat is a system of water supply consisting of a ground tunnel connected to the surface by a series of shafts, which uses gravity to bring water table to the surface. Qanats are usually dug where there is no surface water and were originally invented by Iranians. It is believed that around 800 BC, coal miners in northeastern Iran improvised some canals in order to extract the water from the coal mines. The technology was gradually applied by farmers and spread all over the plateau of Iran. About 525 BC it reached Oman and Saudi Arabia by Iranians and Persian campaigns.

Muslims introduced Qanat to Africa and Yafuga (a qanat) was created by Muslims in Madrid . The Spanish initiated qanats in Mexico in 1520 AD. From there, it was taken to Los Angeles in 1520 AD. This Hydraulic system was spotted in Chile, too. Creation of qanats in Asia enjoys great antiquity as well. Qanats are also known as ‘karez’ (Afghanistan), ‘galeria’ (Spain), ‘khotara’ (morocco), ‘aflaj’ (Arabian peninsula), ‘forggara’ (north Africa), ‘kanerjing’ (china), ‘auon’ (Saudi Arabia/Egypt), reflecting the widespread dissemination of the technology across ancient trading routes and political maps. The immediate outlet, mazhar, is the point is very important: it is well maintained and cemented.

The use of water use is monitored on regular basis. A tunnel, or payab, channels water under the residential area to the cultivated land. A sloping corridor with steps leads from the surface to the payab. The first payab is located in the main square and is used for taking drinking water. A network of smaller payabs runs from the main payab.

http://www.rainwaterharvesting.org/international/qanats_iran.htm

Dear Behrouz,

An interesting links. The links tells us the ancient ways /technology of rainwater harvesting ‘Qanat.’which started/invented in Iran and later spread to Oman, Saudi Arabia, to Africa, Asia and Europe, and even in Latin America

@Behrouz Ahmadi-Nedushan, excellent links and detailed reply. Thanks for this great sharing.

The natural detention of rainfall is diminished by so many human activities. The best way could often be to restore woods and other humid areas.

Rainwater in Germany is polluted, the aerosols being washed from the air. It cannot be recommended for drinking.

Rainfall water may be not recommended for drinking , but I think it was good for agriculture.

SIRAF- A Successful TRADITIONAL Way of Water - Harvesting in Iran

http://www.comap.ca/kmland/display.php?ID=141&DISPOP=VRCPR

Another Sample of Iranian ART in water harvesting systems.

Attached Photos:

Captured by me:

8th National Conference on Watershed Management, Lorestan, 16-17 May, 2012

Follow the link to see the additional photos.

http://safireaflak.ir/fa/news/11990/%DA%AF%D8%B1%D8%AF%D8%A7%D8%A8%20%D8%B3%D9%86%DA%AF%DB%8C%20%D8%AE%D8%B1%D9%85%20%D8%A2%D8%A8%D8%A7%D8%AF%20/

Dear All,

The Dr. Behrouz Ahmadi-Nedushan`s CITY.

https://www.researchgate.net/profile/Behrouz_Ahmadi-Nedushan?_sg=aWyK0NtCNoOYNxEbf1GYhfMh6ZQJUhQJbUXe53zSL%2B9qZbWYhG77ZGwrh2ediDvJP6QVCf1fNPsUzYP6SWDzlA%3D%3D

GANAT Water Harvesting System behind the highest windward in the WORLD!

DOWLAT-ABAD Garden, Yazd Province, Yazd, Iran,

As elsewhere throughout the country’s high desert, water is delivered to the garden via GANATs.

A ganat,a Persian invention that began around 2000BC, is a deep well from which tunnels, some running as long as 25 miles contribute to a system of more than 100,000 miles of water delivery.

Attached Photo:

Captured by me:

9th National Conference on Watershed Management, Yazd, 30-31 Oct, 2013

Thanks dear @Raoof for very valuable information and resources regarding this thread! Our friend @Behrouz, You and other scientists from Iran do very good job, an ART in water harvesting systems!

Dear @Ljubomir, @All.

IRANIANS have a long history in the Water-related sciences.

A Great hydrologist:

Abubakr-Mohammed-Ebn-Alhassan-Ashaseb-Alkaraji in IXth Century.

http://en.wikipedia.org/wiki/Al-Karaji

http://www.waterhistory.org/histories/karaji/

Dear Ronald,

Thanks for informing that rainwater is used in Romania only in few drought affected areas!

Dear Raoof et al.

I read with an interest of the publication related to traditional rain harvesting in Iran by "Soheil Mohajeri. 2010. SIRAF- A Successful Traditional Way of Water- Harvesting in Iran . European Commission".

The key points are as follows:

• the average annual rainfall in Iran is 252 mm, water is a scare resource and 85% percent of the country consists of dry lands

• the traditional water supply system in Iran was a combination of rainwater harvesting, underground water reservoirs and underground gardens

• traditionally rainwater harvesting consists of rectangular dugout puddles built on the mountain. These rainwater harvesting puddles had outlets to transfer extra water to the next pounding and to wells and underground water reserves

• traditional rainwater harvesting puddles were mistakenly identified by archaeologists as graves!

Dear Behrouz,

your time table for introducing Qanats to America is somewhat to early.

Mexico was conquered and destroyed 1519/20 and it took the Spaniards a few years to get deeper into the country, the main interest being mining.

The first Spaniard getting to the plain where finally Los Angeles developed arrived more than twenty years later.

Where water is scarce, it is appreciated much and used often well.

However, irrigation in India, North Africa and Mexico/Southern US uses ground water, which is used mostly individually at the expense of drying out the whole landcsape - not good for a prosperous future. If everybody can use as much as he wants, the reserves are dwindling away fast.

Another problem of drying out the continents and raising the level of the oceans is the amount of water used in the mushrooming cities. It is flowing down fast through the canalizations.

I agree with the comments above. Management of water resources is very important issue and we have to use every possible resources carefully and think of future generations as well!.

As water becomes more scarce the importance of how it is managed grows vastly. Finding a balance between what is needed by humans and what is needed in the environment is an important step in the sustainability of water resources.

The field of water resources management will have to continue to adapt to the current and future issues facing the allocation of water. With the growing uncertainties of global climate change and the long term impacts of management actions, the decision-making will be even more difficult. It is likely that ongoing climate change will lead to situations that have not been encountered. As a result new management strategies will have to be implemented in order to avoid setbacks in the allocation of water resources.

Management of water resources is necessary because these resources are becoming less.

Dear Herbert,

Thank you for your inputs. we have to find out alternative water resources like rainwater!

Dear Roland,

By harvesting rainwater we can reduce pressure on the existing water resources

“Let not a single drop of water that falls from the skies flow to the sea, without being used for the benefit of man” King Parakramabahu the Great- Sri Lanka (1153-1186 A.D)

Dear Behrouz,

As part of sustainable use of water resources, allocations of water should be made in such a way so that the needs of consumptive use (urban, irrigation, stock and domestic, and commercial) and environmental uses (wetlands, aquatic biota, estuaries and groundwater-dependent ecosystem) are balanced. Climate change (changes in rainfall, rise of temperature, sea level rise-salt water intrusion, evaporation) all will have an impact on future water resources; therefore we have to make efforts to save these precious resources!

Brad Lancaster`s Travel Memorabilia to IRAN:

Trip to Iran by Invitation of the Iranian Rainwater Catchment Systems Association

http://www.harvestingrainwater.com/2014/05/17/my-trip-to-iran-by-invitation-of-the-iranian-rainwater-catchment-systems-association/