Friday, September 28, 2018

Water scarcity and Solutions for Thar Desert











Water scarcity and Solutions for Thar Desert

 Introduction
Deserts in Pakistan constitute a significant part of the country’s geography, especially in the central and south-eastern regions. The major deserts of Pakistan include Thar, Cholistan, Thall and Kharan deserts. These areas receive very little rain fall and are characterized by large tracts of barren wastelands with formation of sand dunes rising sometime to 150 meters above ground level. The vegetation cover in these deserts is sparse and primarily comprises of drought resistant and stunted bushes and trees, mainly acacias, and grasses.
The Thar Desert is a large arid region in the northwestern part of the sub continent , 50,000 km2 (19,000 sq mi) of the desert is within Pakistan.  The desert comprises a very dry part  Thar mostly consists of barren tracts of sand dunes covered with thorny bushes. The only hills of the district, named Karon-Jhar, are in the extreme south-east corner of Nagar Parkar Taluka, a part of Thar. These hills are spread over about 20 kilometers in length and attain a height of 300 meters. Covered with sparse jungle and pasturage, they give rise to two perennial springs as well as streams caused after rain. The Thar area has a tropical desert climate. The months of April, May and June are the hottest ones during the day. The average maximum and minimum temperatures during this period remain 41 centigrade to 24 centigrade respectively while December, January and February are the comparatively coldest months with average maximum and minimum temperatures 28 centigrade to 9 centigrade respectively. Rainfall varies from year to year. Most of the rain falls in the monsoon months between June and September whereas the winter rains are insignificant

The Problem

People who have been to the Thar desert understand the value of water for Thar ,  The women travel for several km to fetch 2-3 pitches of water.  .A Thar resident says “Migration was earlier a way for men to sell newly cut crops and waits for the cotton-picking months of June and July. Now, it’s our only option to stay alive.”As a result, men are now shifting their entire families to various talukas and villages across Sindh. “My biggest fear when I’m out making a living is, what if my family dies while I’m gone,” he says “Because I know for a fact that there’s nothing to eat in my village anymore.”
Sukho and his family walked for two days from Naharo Bheel village to get to Chhachhro and are now on their way out of here, too. His mother speaks up: “I’ve seen three droughts in the past 50 years but this is the worst.” Sukho’s wife has already been shifted to a village in Sanghar district named Bhairani. “Only 50 people are left in my village,” he says. “So far, 450 families have left.”
On the main road leading towards Chhachhro, which is the most affected among the six talukas in Tharparkar, signs of drought are hard to ignore. There have been ‘mass migrations’ in the recent past and present, officials say. Families can be seen on the main highway leading to Umerkot and Mithi, some walking, some huddled together on camels or on top of Suzuki pickups. Carcasses of dead livestock can be seen lying on the roadside.
“Thar has been completely dry so far. And even if it rains it will have zero impact on the dying crop, and the livestock around Chhachhro.” He adds that this year’s drought reminds him of the one in 1987. “It was called ‘Karo Dukkar’ meaning black drought,” he muses. “It was the same situation: malnutrition all around, livestock dying, people migrating as a result. The problem is that the government sees it as an isolated challenge.”
Back in Umerkot, Mohammad Siddiq, representing Aware, insists the situation is very different from what it was before. “It took countless meetings to convince the provincial officials that there is a problem in Thar. Chhachhro and a newly made taluka, Dahali, are among the worst affected when it comes to malnutrition and drought. Thirty-one people committed suicide this year, the reasons being the lack of financial resources as well as food shortages.”
Dr Ashok links the present situation in Chhachhro in particular and Thar in general to the need for introducing “long-term solutions on an emergency basis”.
“If it doesn’t rain the crop won’t grow,” he explains. “If the crop is not sold, how will a family that relies financially on livestock continue to feed it? Even livestock that survives the drought is useless for a farmer, because it won’t be able to breed and will eventually die. This situation won’t go away by itself.”
He adds that “the situation is critical, more than it was before, even though facts were indeed exaggerated earlier. By the end of last year, it hadn’t rained in five out of 17 union councils in Chhachhro. A hue and cry was made. This time around, it didn’t rain in any of the 17 union councils of Chhachhro, and yet there is no hue and cry.”
Dr Ashok says that in the long term, it might cause an irreparable damage to the land and the people. “The situation requires us to listen to a hari or a kisaan for a change.”
  Thirty-year-old Marubhat, a resident of Samo Bheel village — a two-hour drive from Chhachhro — decided to end her life on Aug 23 after she had failed to provide food for her children. Soon after her death, her home was visited by reporters and social workers where during interviews her family attributed the cause of her death to persistent financial problems. Now, the family has refused to speak to the media.
In previous years, 24 suicide cases were reported in 2011 and 35 in 2012. But this is the 31st death in Tharparkar district as a result of suicide within just seven months, officials say.
These suicides are largely attributed to a rise in cases of domestic violence and poverty in the area. A renowned social worker and CEO of Hisaar Foundation, Dr Sono Kangharani, says that the main reason behind the suicides is in fact poverty. “There are multiple factors, but poverty stands out as it points towards a need which continues to remain unfulfilled. This woman thought of taking her life as she found no way out of the dilemma she was faced with,” he adds.
According to data compiled by AWARE, an NGO working in Thar, suicide is a dilemma faced by both women and men. “We are pressurised to avoid giving exact figures,” says Ali Akbar Rahimoo, executive director at AWARE. “But these suicide cases cannot be looked at in isolation as they are part of a bigger problem which is poverty due to drought.”
In another case, a man left his home around afternoon after an argument with his wife over financial issues. By night, one of the locals found his body inside a well near Samo Bheel village and informed his wife. Explaining the gravity of the situation, Rahimoo says: “Chhachhro, which is one of the biggest out of the six talukas of Thar, has a single Rural Health Centre, which is called a Taluqa Hospital on paper.”
Every local or an NGO official whom Dawn spoke to asked to call on the public’s attention to the drought in Thar.This year the drought is reported to be the worst than the previous ones that occurred in 1974 and 1986. A drought is a direct result of late monsoon or in case of Thar a lack of it. Usually, the period for monsoon is between June 15 and August 15, after which drought is declared. Dr Khangharani, while referring to a belief here says, “The festival of Thaddri — Raksha Bandhan — is an indicator that it won’t rain anymore in Thar. And this is exactly what happened here as the festival was celebrated in the month of August.” But he adds that such a drought is rare. “Rare because there is zero grass production and zero fodder which has a direct effect on the livestock and makes it difficult for the people to cope the aftermath of drought.”
For many months, the local NGOs and newspapers were up in arms with the provincial government over the number of deaths as a result of drought. A policy on drought was recently introduced by the provincial government but Dr Khangharani, who is among the committee members who worked on the policy, is not that hopeful. “Nothing will happen in the coming months. At present, we are waiting for the said policy to be passed in the assembly. The government will most probably end the topic of Thar by distributing wheat among the residents. Distributing wheat won’t resolve it. Similarly, vaccinating children won’t end their hunger. It is a question of saving the livestock in Thar which the Tharis depend on. It continues to die as we speak,” he says.
The ensuing migration in Thar as a result of drought includes two kinds of people, those who are moving temporarily and those who are moving permanently this time around. Those who migrate with their entire families for a year, move to the western and northern parts of Sindh, mostly near a barrage. These places include Umerkot (where people settle near the Nara canal), Mirpurkhas and Badin (where most migrants settle near the Kotri barrage).
The reason the entire family moves together is to look for a chance to work on the fields. “Cotton-picking and chilli-picking starts from Sept 15, for which these people migrate earlier and then come back a year later. Also, most people who migrated recently and continue to do so may stay back. Because they have to pay off loans taken for the crop and lack of opportunities in Thar,” explains Dr Khangharani.
Gautam Rathi, who is among the board of directors at Thardeep Rural Development Programme (TRDP) Chhachhro, says there is vulnerability in Thar due to a lack of comprehensive policy. “If we want to take into account the number of policies that are made then we don’t need to look anywhere else. But we are not questioning the policy rather its implementation.”
Suggesting solutions for the Thar drought, Dr Kangharani and Rathi are of the opinion that the livestock needs to be saved on an immediate basis. “Mobile health teams should be assigned for various places so that they can help those who can’t reach the taluka hospital or a dispensary. Also, clean drinking water for Thar will help a lot in saving the livestock and if they survive then it will be easier for the people to survive longer,” says Dr Khangharani.
 Children Deaths
The provincial health authorities admitted before the Sindh High Court (SHC) on Thursday that 1,340 children have died in drought-hit areas of Tharparker .  . While statistics often mask the real tragedy, sometimes they are useful to illustrate how deep our rot is. In the past month alone, there have been 47 deaths of children in Thar due to malnutrition. The number is upwards of 155 in the last three months. The number is gut-wrenching but the response that varies from apathy to denial, deflection to lip service, is beyond shameful.
Eight children died on Saturday in Sindh's Tharparkar district due to viral infections and malnutrition, taking the total death count in the region for similar cases to 12 so far in February, sources in Mithi Civil Hospital told DawnNews.
The trend of infant deaths in the region seems to have carried on from January, during which 54 infants below the age of five lost their lives due to various health issues, sources said.
According to data shared by the medical superintendent at the rural health centre in Chhachhro, up until March 2016, the number of dead — mostly children — stood at seven. But NGOs say the number is much higher. Ali Nawaz, the social mobiliser with an NGO named Aware in Chhachhro, says, “Government-run hospitals only quote deaths that occur on their premises. They don’t count the children who die in basic health facilities and dispensaries. According to our data, 112 deaths had occurred till March.”
Solutions
According to a study of the Pakistan Council for Research on Water Resources (PCRWR), the entire Thar Desert receives around one trillion liters of rain annually “sufficient, if stored, for three years to meet domestic water needs of the Tharis and their livestock. But, more than 95 per cent of it is lost under sand dunes or evaporates in the sizzling summer due to inadequate storage and rainwater harvesting facilities
Traditionally rain water is stored in Kunds made in farms or homes for drinking purpose. Some big tanks or Talabs are constructed in villages to store rain water for bathing, animals and also for drinking water. 
The average annual rainfall in Thar Desert area is 350mm. People here are conventionally harvesting 0.06% of total annual rainfall only enough to meet their one fourth of yearly drinking water needs. Sukaar estimates that by harvesting 0.25% of total annual rainfall will maximize current rainwater harvesting capacity by three times – this could enable people to meet their drinking water needs. Moreover, by harvesting further 0.28% of total annual rainfall the 23% of total cultivable land of Tharparker could also be cultivated to produce low delta Rabi crops enough to meet entire food needs of people and to cope with hunger during frequent droughts periods in the area
Underground water storage tanks are constructed by local craftsmen with local materials. During the rainy season (once per year) the rain falls on the cemented dish-shaped yard, and goes through a small hole into the tank underneath.  Once in the tank, the water is kept cool (so it doesn’t evaporate) and relatively pure. A lid above the tank allows water to be withdrawn for use by the family for drinking and cooking. While this solution is simple, it is certainly effective and inexpensive – which is why we can build 1,600 of them.
Although there are only 12” of rain each year in the Thar Desert, it is pure water. In Thar, 80% of groundwater is too saline to drink. Since surface water is seasonal, it can’t be relied upon for the dry season. Collecting rainwater saves people in the community a lot of walking to find a well with “sweet” water in it.Solutions lie in construction of underground tanks to harvest the Rain Water whenever it would rain. The rain water stored in this manner would be used for drinking purposes by the poor people of Thar
Rainwater Harvesting (RWH) project collects and store rainwater for later usage with ponds being one of the most effective and commonly used RWH structures in the area . The larger village-level pond can store approximately 1 million liters of water while the smaller household-level pond has a storage capacity of 8,000 liters water each. RWH structures collect and store rainwater for later usage (for drinking water, cooking, etc). These are particularly important in dry, desert climates that receive little to no rainfall except for a few months during the year. One of the most effective and commonly used RWH structures in deserts, including in Pakistan’s deserts, are large ponds. Depending on the size, these large ponds store water for up to 8-9 months of the year, thus providing desert residents with drinking water for the dry months of the year.
Both pond types are circular and bowl-shaped. The larger village-level pond will be 12 feet deep, and the diameter of its upper rim will be 80 feet and the bottom, 16 feet. It has a storage 1 million liters of water. It is constructed in an excavated pit which will be pressed and lined with a water-proof geo-membrane. Brick masonry will be added on the geo-membrane before the entire structure is covered with concrete. Two hand pumps will be installed to pump water from the pond. The smaller household-level ponds will be built in the backyard of each household. They will be constructed using a very thin lining of cement and sand mortar as well as a concrete-mud mix. They will be up to 3.5 meters deep and have a diameter of 2 meters. These smaller ponds will be able to hold 8,000 liters of water each.
As Tharparkar is a hot desert with high temperatures throughout most of the year, complete avoidance of evaporation is impossible. However, evaporation from traditional rainwater structures in the region is 60%-70%, while these ponds have an average annual evaporation rate of no more than 20%. Sukaar’s RWH ponds have built-in structures that substantially reduce evaporation. Firstly, the circular shape of the pond reduces evaporation (Square or rectangular ponds have higher evaporation rates.) Secondly, shrubs and bushes will be planted outside the pond’s wall, and this too will help reduce evaporation. Finally, evaporation occurs at a faster rate if the water in the ponds remains unused for the first couple of months following the rain season.  
Water conservation experts of PCRWR have suggested that piped roof water harvesting, hamlet level chonra pond, hamlet level nadi pond, chalho pond and dug well recharging system could help conserve huge stock of rainwater. But, introduction and promotion of such water conservation techniques was not possible without one time investment by the government.
 At hamlet level, ponds are used for saving water for the community, and at the village level   delay action dams. Also, in low-lying areas, flood protection walls not only save houses from getting flooded but also allow for water to pool up and be used for other purposes. The construction of a large covered pond with the capacity to supply the domestic and drinking water needs of 20 families (135 villagers) for more than eight months. The solution lies in laying a geo-membrane sheet under the floor of these (ponds) to check seepage, and cover them with roofs that help check evaporation of stored rainwater during the sizzling summer days

Reverse Osmosis Plants

By installing a large number of reverse osmosis (RO) plants in the Thar region, the Pakistan People’s Party and the Sindh government have launched a long-term project aimed at resolving the issue of drinking water in this region once and for all.
He recalled that the Sindh government had seven years back planned installation of 880 RO plants in Tharparkar. Out of them, 88 major plants producing 100,000 gallons per day each and another 418 producing 10,000 gallons per day each had already been completed while work on the remaining plants was in full swing, the minister said.
Water Towers that can draw water from air
A tower supplying drinking water in a way that’s both practical and convenient—that served as the impetus for a new product called Warka Water,an inexpensive, easily-assembled structure that extracts gallons of fresh water from the air.

The invention from Arturo Vittori, an industrial designer, and his colleague Andreas Vogler doesn’t involve complicated gadgetry or feats of engineering, but instead relies on basic elements like shape and material and the ways in which they work together. 
At first glance, the 30-foot-tall, vase-shaped towers, named after a fig tree native to Ethiopia, have the look and feel of a showy art installation. But every detail, from carefully-placed curves to unique materials, has a functional purpose.
The rigid outer housing of each tower is comprised of lightweight and elastic juncus stalks, woven in a pattern that offers stability in the face of strong wind gusts while still allowing     air to flow through. A mesh net made of nylon or  polypropylene, which calls to mind a large Chinese lantern, hangs inside, collecting droplets of dew that form along the surface. As cold air condenses, the droplets roll down into a container at the bottom of the tower. The water in the container then passes through a tube that functions as a faucet, carrying the water to those waiting on the ground.
Using mesh to facilitate clean drinking water isn’t an entirely new concept. A few years back, an MIT student designed a fog-harvesting device with the material. But Vittori’s invention yields more water, at a lower cost, than some other concepts that came before it.
″[In Ethiopia], public infrastructures do not exist and building [something like]  well is not easy,” Vittori says of the country. “To find water, you need to drill in the ground very deep, often as much as 1,600 feet. So it’s technically difficult and expensive. Moreover, pumps need electricity to run as well as access to spare parts in case the pump breaks down.”
So how would Warka Water’s low-tech design hold up in remote sub-Saharan villages? Internal field tests have shown that one Warka Water tower can supply more than 25 gallons of water throughout the course of a day, Vittori claims. He says because the most important factor in collecting condensation is the difference in temperature between nightfall and daybreak, the towers are proving successful even in the desert, where temperatures, in that time, can differ as much as 50 degrees Fahrenheit. 
The structures, made from biodegradable materials, are easy to clean and can be erected without mechanical tools in less than a week. Plus, he says, “once locals have the necessary know-how, they will be able to teach other villages and communities to build the Warka.”
In all, it costs about $500 to set up a tower—less than a quarter of the cost of something like the Gates toilet, which costs about $2,200 to install and more to maintain. If the tower is mass produced, the price would be even lower, Vittori says. His team hopes to install two Warka Towers in Ethiopia by next year and is currently searching for investors who may be interested in scaling the water harvesting technology across the region. 
“It’s not just illnesses that we’re trying to address. Many Ethiopian children from rural villages spend several hours every day to fetch water, time they could invest for more productive activities and education,” he says. “If we can give people something that lets them be more independent, they can free themselves from this cycle.  
 Water Extraction Equipment
 Water-Gen has developed an Atmospheric Water-Generation Units using its "GENius" heat exchanger to chill air and condense water vapor."The clean air enters our GENius heat exchanger system where it is dehumidified, the water is removed from the air and collected in a collection tank inside the unit," says co-CEO Arye Kohavi.
"From there the water is passed through an extensive water filtration system which cleans it from possible chemical and microbiological contaminations," he explains. "The clean purified water is stored in an internal water tank which is kept continuously preserved to keep it at high quality over time."
Capturing atmospheric humidity isn't a ground-breaking invention in itself -- other companies already sell atmospheric water generators for commercial and domestic use -- but Water-Gen says it has made its water generator more energy efficient than others by using the cooled air created by the unit to chill incoming air.
"Several companies tried to extract water from the air," says Kohavi. "It looks simple, because air conditioning is extracting water from air. But the issue is to do it very efficiently, to produce as much water as you can per kilowatt of power consumed."
He adds: "When you're very, very efficient, it brings us to the point that it is a real solution. Water from air became actually a solution for drinking water."
The system produces 250-800 liters (65-210 gallons) of potable water a day depending on temperature and humidity conditions and Kohavi says it uses two cents' worth of electricity to produce a liter of water. Water-Gen says it has already sold units to militaries in seven countries, but Kohavi is keen to stress that the general population can also benefit from the technology.
He explains: "We believe that the products can be sold to developing countries in different civilian applications. For example in India, [drinking] water for homes is not available and will also be rare in the future. The Atmospheric Water-Generation Unit can be built as a residential unit and serve as a perfect water supply solution for homes in India."Kohavi says Water-Gen's units can produce a liter of water for 1.5 Rupees, as opposed to 15 Rupees for a liter of bottled water.
Dirty water
Another product Water-Gen has developed is a portable water purification system. It's a battery-operated water filtration unit called Spring. Spring is able to filter 180 liters (48 gallons) of water, and fits into a backpack -- enabling water filtration on the go.
"You can go to any lake, any place, any river, anything in the field, usually contaminated with industrial waste, or anything like that and actually filter it into the best drinking water that exists," says Kohavi.
Major Alisa Zevin, head of the Facilities and Specialized Equipment Section for the IDF, says the unit is revolutionary for them.
"This unit gives logistic independence for the forces and makes us ensure that we provide the soldiers high quality water," she says.
In 2013, the IDF took Spring to the Philippines after Typhoon Haiyan devastated the island country and left 4.2 million people affected by water scarcity. The system filtered what was undrinkable water into potable water, and that is what Water-Gen hopes to accomplish elsewhere where the technology is needed.
"It's something as a Westerner you cannot understand because you have perfect water in the pipe, but people are dying from lack of water," says Kohavi. Although Water-Gen's developments aren't a solution for the water crisis, Kohavi believes that the technology can do for countries that lack clean water.  


UPDATE 



I.A. Rehman
SEVERAL thousand residents of three villages in Thar are appealing to the conscience of the people of Pakistan, especially of the custodians of power, to save them from ruin, as their lands have been submerged in the waters of the Gorano Dam.
The dam is an artificial lake created in a depression where water discharged after mining for coal is collected through a 35-kilometre-long pipeline. About 1,500 acres of land are already under water and eventually the lake may cover 5,000 acres, belonging to Gorano and two other villages. Many landowners have accepted the compensation offered by the Sindh Engro Coal Mining Company (SECMC) while some have not.
The Sindh government is reported to have announced a compensation package of Rs950 million for about 750 households. Each household will receive a term deposit certificate worth Rs1.2m that should yield a monthly income of Rs10,000.
The SECMC also claims to have provided jobs for young men and has opened a school in Gorano. The Sindh government is handing over 37 schools to the company, which has also contributed to the renovation of the Islamkot press club. A family park including a recreation area for children has been built on the highest mound overlooking the lake to attract tourists. At the moment it appears to be a cruel joke, as all that the villagers can see is the land under water that was the source of their livelihood for centuries and which has been taken away from them through means they do not consider fair.
The Gorano story is only a small part of the much bigger threat the people of Thar are facing.
The claims made by the government and the mining company regarding compensation and other help to the affectees may well be true, but a good number of them are not satisfied. They do not like the master-client pattern of dealing with them instead of being treated as an equal party to a negotiated settlement. A few Gorano citizens who had declined to accept the compensation offer filed a petition in the Sindh High Court in May 2016. They are unhappy that no proceedings have taken place on the many dates fixed for hearing this year.
The complaints aired by the Gorano community at a public hearing organised for the National Commission for Human Rights last Saturday made it clear that the matter of compensating all those who have been affected by the creation of the Gorano Dam, or Gorano pond as the SECMC now describes it, is quite complicated.
Alo Kohli, the head of 10 households, claims to have been working on 500 acres and he wants to be given alternative land. Dost Ali wants to be compensated for the house that has collapsed. A peasant wants to surrender his piece of land because the lake has blocked access to it. Shrinkage of gowcher (grazing land) is a common grievance as many villagers depend more on cattle breeding than farming. The fact is that the Gorano Dam is going to disrupt the economy of the villages affected.
Land records have not been updated for many years. In many cases, land is occupied by the grandchildren of persons whose name is given in the record. Above all, the scheme of offering compensation to only landowners is unfair. It is necessary to apply to the displaced people of Thar the World Bank formula of compensating squatters too. The SECMC says it is offering land to landless haris. One should like to know the scale of this plan to be reassured of its adequacy.
It is said that originally the water pumped out for mining was to be stored at Weeravo, close to the Rann of Kutch, but the idea was given up in order to avoid any possible protest by India. The Gorano inhabitants say that as equal citizens of Pakistan they too have a right to be heard.
As the Thar Coal project progresses it will be necessary to create at least one more dam or pond or possibly more. Will the people affected by the new dams fare any better than the residents of Gorano?
The Gorano story is only a small part of the much bigger threat the people of Thar are facing. Several experts have argued that the entire economy of Thar is seriously threatened. Out of the total Thar area of 1,960 square kilometers, 900sq km, a little less than 50 per cent, has been handed over to the SECMC. What will be done with the land not used for mining? If it is not given back to the owners, where and how will they survive? The gowcher area now available for grazing is grossly inadequate for sustaining more than 5m heads of cattle.
Worse, rapid depletion of underground water resources could make the area unlivable for humans and beasts alike. The mining operation is draining not only the entire aquifer of sweet rainwater but also the reservoir of saline water before the coal bed can be reached. Reports of plans to desalinate water twice to make it fit for drinking or even for irrigation do not inspire confidence.

For years now, attention has been focused on one result of Thar’s economic crisis — the death of infants. Concentration on the supply of food and improvement of hospital services will make little difference. These efforts need to be integrated with a Thar uplift program  of employment generation and girl’s education and employment so that girls do not become mothers in childhood and don’t give birth to babies with multiple vulnerabilities.

Conclusions
 Suicide cases and children death cannot be looked at in isolation as they are part of a bigger problem which is poverty due to drought.”Livestock farming in Tharparkar has historically survived in conjunction with the seasonal migration that most residents would undertake in the dry winter months to more fertile areas of the province - both to work as farm laborers and to take their animals to areas where more fodder was available. The practice of allowing livestock to migrate seasonally, however, has been restricted by the government, and with the depletion of stores in Tharparkar, many animals have been dying of hunger or disease.  
According to a study of the Pakistan Council for Research on Water Resources (PCRWR), the entire Thar Desert receives around one trillion liters of rain annually “sufficient, if stored, for three years to meet domestic water needs of the Tharis and their livestock. But, more than 95 per cent of it is lost under sand dunes or evaporates in the sizzling summer due to inadequate storage and rainwater harvesting facilities. Traditionally rain water is stored in Kunds made in farms or homes for drinking purpose. Some big tanks or Talabs are constructed in villages to store rain water for bathing, animals and also for drinking water. 
The average annual rainfall in Thar Desert area is 350mm. People here are conventionally harvesting 0.06% of total annual rainfall only enough to meet their one fourth of yearly drinking water needs. Sukaar estimates that by harvesting 0.25% of total annual rainfall will maximize current rainwater harvesting capacity by three times – this could enable people to meet their drinking water needs. Moreover, by harvesting further 0.28% of total annual rainfall the 23% of total cultivable land of Tharparker could also be cultivated to produce low delta Rabi crops enough to meet entire food needs of people and to cope with hunger during frequent droughts periods in the area
Underground water storage tanks are constructed by local craftsmen with local materials. During the rainy season (once per year) the rain falls on the cemented dish-shaped yard, and goes through a small hole into the tank underneath.  Once in the tank, the water is kept cool (so it doesn’t evaporate) and relatively pure. A lid above the tank allows water to be withdrawn for use by the family for drinking and cooking. While this solution is simple, it is certainly effective and inexpensive – which is why we can build 1,600 of them.

For Thar’s desert dwellers, livestock is an essential part of their existence and can mean the difference between life and death.And while Tharis do migrate to other parts of Sindh to find seasonal work; reports indicate that some families are leaving their native areas permanently.
Drought-like conditions were also experienced earlier this year, with a number of children reportedly dying from malnutrition.  While the provision of food and water will temporarily stave off starvation, a plan needs to be put in place to save the area’s livestock as well. Hence supplying fodder to the people’s animals must also be a priority. And as drought is not uncommon in Thar, for the long term policies need to be framed so that the people and livestock in the area are protected from the devastating effects of natural disasters.
The Thar coal projects present both an opportunity and a danger. The development has employed local labor and technicians, heavy vehicles drivers are also local, even woman. This is a positive development. The danger, however is that the resettlement and land acquisition process will leave many families without any assets , these are nomadic families and have no documents to any land , therefore under the current resettlement regime that will get neither land nor compensation, these needs to be put in place an out of box solution for  these land nomads. The issue is that the Sindh government is a share holder in the Thar developments and is also the environmental and social watch dog, these is a serious conflict of interest. Perhaps third party involvement in these issues is desired .
We should understand that the elimination of absolute poverty is the duty of the Islamic State of Pakistan, it should simply be impossible for children to die and farmers and women tom commit suicide in Pakistan. We need to put on place a comprehensive plan that recognizes the primacy of live stock in the Tharis assets base and the need to construct improved rain harvesting ponds to ensure both fodder and basic food.

Update: Jan., 14, 2019:
Tharparkar is facing drought yet again. Droughts and famines are a regular feature of life in Tharparkar. Barring a few pockets that received rainfall in 2017, the rest of the area has not been getting any rain for the last four years. Thar`s agro-pastoral life revolves around water and fodder. Provincial and federal governments tend to address the issues faced by the local population using a relief-based approach. A sustainable, institutional oversight has so far eluded this least developed region where people endure harsh conditions regularly. Every drought triggers migration among communities. This migration is in addition to the seasonal ones that take place at the time of cotton-picking or sugar cane and wheat harvesting. Groundwater levels drop considerably in the absence of rainfall. Livestock, which is the community`s only source of livelihood, forces them to leave their area in search of fodder and water in canal command areas. No permanent arrangement for fodder availability, like fodder banks, exists in Tharparkar during the drought. This is despite the fact that livestock plays a central role in sustaining economic life in the area. It provides them with milk and butter, but animals suffer a loss of immunity during every drought. As a result, milk production drops considerably, causing undernourishment especially among expecting mothers. This makes the survival of malnourished newborns difficult. Based on the projected animal population number and the human population of 1.6 million as per the latest census, one individual maintains around four animals in Tharparkar. Immunity loss necessitates preventive vaccination among animals, but its coverage is hardly 20pc in Sindh for want of resources, an official admitted. The livestock sector has a share of 58.92pc within the country`s agriculture sector, which contributed 18.9pc to GDP as per the 2017-18 Economic Survey of Pakistan. The estimated livestock population in 2017 was 41.68m in Sindh. Only 25% vaccination coverage is available in Sindh and Thar .
,Cholistan seems relatively better managed. Cholistan, however, had a smaller estimated human population of roughly 220,000 in 2017 along with 1.6m heads of livestock. The Punjab government`s Cholistan Development Authority (CDA) deals with this area exclusively. Within the provincial livestock department, a directorate looks after the affairs of Cholistan. `We provide livestock farmers with wanda (feed supplement) on a cost-to cost basis throughout the year at fixed entry/exit points,` he said. He added that ponds are built in the area for human and livestock populations in addition to an old natural waterway that is connected with pumping stations.
Since 2018, he said, his department has been buying camel milk for Rs42 per litre and keeping it in chillers. It is then sold for Rs120 per litre in Lahore.He said that the department also purchased cattle milk in 2010. But the private firms` intervention jacked up the market price, which benefited farmers.`The animal vaccination coverage in 100pc,` he remarked.

Around 17 chillers (out of 153 in Sindh) were set up in Thar. But those were part of the foreign-funded Sindh Agriculture Growth Project (SAGP). Reportedly, only three of them are functioning. Since a large number of livestock left Thar for want for fodder, milk could not be collected in the rest of the chillers. The provincial livestock department has provided three livestock farmers with solar powered submersible pumps to lift groundwater and grow fodder on an experimental basis.He said reverse osmosis plants are not a solution to Thar`s woes. Managing these plants is difficult even in urban areas. The Sindh government needs to focus more on rainwater harvesting projects in Thar,` he said.


Analysts have rightly described Thar as a classic example of bad governance. Despite its 11 years of rule in Sindh, the PPP has not been able to resolve a simple health crisis in a single district with a population of just over one million. The death of children is just a reflection of long-time marginalisation and extreme poverty in the region, for which no one is willing to take responsibility. Until and unless the core issue of social and economic exclusion is addressed in Thar with concrete long-term planning, the mere monitoring of ad hoc government actions may never yield the desired results.• The writer works at the Pakistan Institute of Labour Education and Research in Karachi.


Thursday, September 27, 2018

Light Emitting Diodes (LED)






Light Emitting Diodes (LED)
Introduction
Light-emitting diode (LED) is a two-lead semiconductor light source. It is a p–n junction diode that emits light when activated. When a suitable current is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons.   This effect is called electroluminescence, and the color of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor. LEDs are typically small (less than 1 mm2) and integrated optical components may be used to shape the radiation pattern. Unlike a laser, the color of light emitted from an LED is neither coherent nor monochromatic, but the spectrum is narrow with respect to human vision, and for most purposes the light from a simple diode element can be regarded as functionally monochromatic
  LEDs are like tiny light bulbs. However, LEDs require a lot less power to light up by comparison. They’re also more energy efficient, so they don’t tend to get hot like conventional light bulbs do   this makes them ideal for mobile devices and other low-power applications The LED is a light source which uses semiconductors and electroluminescence to create light.  LED   uses a small semiconductor crystal with reflectors and other parts to make the light brighter and focused into a single point. Basically, LEDs are just tiny light bulbs that fit easily into an electrical circuit. But unlike ordinary incandescent bulbs, they don't have a filament that will burn out, and they don't get especially hot. They are illuminated solely by the movement of electrons in a semiconductor material, and they last just as long as a standard transistor. The lifespan of an LED surpasses the short life of an incandescent bulb by thousands of hours. Tiny LEDs are already replacing the tubes that light up LCD HDTVs to make dramatically thinner televisions.

History
LEDs appeared as practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared light. Infrared LEDs are still frequently used as transmitting elements in remote-control circuits, such as those in remote controls for a wide variety of consumer electronics. The first visible-light LEDs were of low intensity and limited to red. Modern LEDs are available across the visible, ultraviolet, and infrared wavelengths, with very high brightness.
Working
The LED consists of a chip of semiconducting material doped with impurities to create a p-n junction. As in other diodes, current flows easily from the p-side, or anode, to the n-side, or cathode, but not in the reverse direction. Charge-carriers—electrons and holes—flow into the junction from electrodes with different voltages. When an electron meets a hole, it falls into a lower energy level and releases energy in the form of a photon.
The wavelength of the light emitted, and thus its color, depends on the band gap energy of the materials forming the p-n junction. In silicon or germanium diodes, the electrons and holes usually recombine by a non-radiative transition, which produces no optical emission, because these are indirect band gap materials. The materials used for the LED have a direct band gap with energies corresponding to near-infrared, visible, or near-ultraviolet light.
LED development began with infrared and red devices made with gallium arsenide. Advances in materials science have enabled making devices with ever-shorter wavelengths, emitting light in a variety of colors.
LEDs are usually built on an n-type substrate, with an electrode attached to the p-type layer deposited on its surface. P-type substrates, while less common, occur as well. Many commercial LEDs, especially GaN/InGaN, also use sapphire substrate.
If you connect an LED directly to a current source it will try to dissipate as much power as it’s allowed to draw, and, like the tragic heroes of olde, it will destroy itself. That’s why it’s important to limit the amount of current flowing across the LED.. Resistors limit the flow of electrons in the circuit and protect the LED from trying to draw too much current. 
LEDs create light by electroluminescence in a semiconductor material. Electroluminescence is the phenomenon of a material emitting light when electric current or an electric field is passed through it - this happens when electrons are sent through the material and fill electron holes. An electron hole exists where an atom lacks electrons (negatively charged) and therefore has a positive charge. Semiconductor materials like germanium or silicon can be "doped" to create and control the number of electron holes. Doping is the adding of other elements to the semiconductor material to change its properties. By doping a semiconductor you can make two separate types of semiconductors in the same crystal. The boundary between the two types is called a p-n junction. The junction only allows current to pass through it one way, this is why they are used as diodes. LEDs are made using p-n junctions. As electrons pass through one crystal to the other they fill electron holes. They emit photons (light).

Applications
Early LEDs were often used as indicator lamps for electronic devices, replacing small incandescent bulbs. They were soon packaged into numeric readouts in the form of seven-segment displays and were commonly seen in digital clocks. Recent developments have produced LEDs suitable for environmental and task lighting. LEDs have led to new displays and sensors, while their high switching rates are useful in advanced communications technology. . Light-emitting diodes are used in applications as diverse as aviation lighting, automotive headlamps, advertising, general lighting, traffic signals, camera flashes, lighted wallpaper and medical devices. They form numbers on digital clocks, transmit information from remote controls, light up watches and tell you when your appliances are turned on. Collected together, they can form images on a jumbo television screen or illuminate a traffic light.Oter uses incuude :Indicator lights ; LCD panel backlighting Specialized white LEDs are used in flat-panel computer displays ;Fiber optic data transmission Ease of modulation allows wide communications bandwidth with minimal noise, resulting in high speed and accuracy ; Remote control Most home-entertainment "remotes" use IREDs to transmit data to the main unit; Optoisolator Stages in an electronic system can be connected together without unwanted interaction.
,LEDs serve as the foundation of networked lighting systems that also provide information to other systems connected to an internal building management network. For example, the heating, ventilation, and air conditioning systems could be alerted that certain parts of the building are empty, and could adjust the temperature or shut off the air conditioning entirely.
Energy savings
LEDs use about 85% less electricity than incandescent bulbs and as much as 50% less than fluorescents. The amount saved with fluorescents will vary depending on whether you’re using a fluorescent tube or a compact fluorescent bulb (CFL). The efficiency of a light bulb is measured in lumens per watt and currently LED technology is providing higher lumens per watt than fluorescent, but is not practical for every application a fluorescent source is being used.
One of the main problems with incandescent bulbs is they emit a great deal of energy as heat (that’s why you can burn yourself if you touch a lit incandescent bulb), and this heat signifies that some energy is being wasted instead of converted to light. On the other hand, if you touch an LED light it is typically cool to the touch and will likely not notice any heat at all. This is because more electricity is being converted to light — about 85% more.
A few of the major advantages of LEDs over CFLs are they don’t produce any UV rays, last 5 times longer, save 20% in energy costs and are lead and mercury free.
By design LEDs can last as much as 50 times longer than other bulbs and have lifetimes ranging from 30,000 to 100,000 hours or more at constant operation. Depending on how many hours a day your facility is lit, this can equal a lifespan of anywhere from 6 to 30 years. In comparison, incandescent bulbs only last an average of 1000 to 5000 hours, CFLs last 8,000 to 10,000 hours, and fluorescent tubes have lifetimes of 20,000 to 50,000 hours.
Part of the reason LEDs last so long is because they are durable (no glass components) and do not have a filament (like incandescent bulbs) that can break our burn out. Their illumination comes exclusively from the movement of electrons in a semiconductor material.

Lighting accounts for about 20 percent of the total energy usage worldwide, approximately 1,944 terawatt hours. Because lighting is relatively simple to upgrade, the trend in recent years is to switch to LEDs. Doing so greatly improves energy efficiency; mitigating global warming’s impact and reducing energy dependence on other countries.
Globally, LEDs make up less than 10 percent of lighting systems, according to the U.S. Department of Energy Solid-State Lighting R&D Plan, published in June 2016. But the DOE forecasts LEDs to become the predominant source of illumination—for indoor and outdoor spaces—over the next decade. The DOE’s “Energy Savings Forecast of Solid-State Lighting in General Illumination Applications,” released in September, predicts that by 2035, LED lamps and luminaires will be used in 86 percent of all lighting products in the United States, compared with 6 percent in 2015. That translates into an annual savings of 1,495 terawatt hours over traditional lighting systems, nearly the total annual energy consumed by 45 million U.S. homes today. This adds up to nearly $52 billion in energy costs savings.
Because LEDs are semiconductor devices, integrating additional electronics in the bulbs, such as occupancy and daylight sensors connected to a network interface, provides the bulbs with new functions. This design enables, for example, the automatic dimming of lights when there’s sufficient natural light in the room, and it senses the presence of people in a room and adjusts overhead lighting accordingly. These capabilities not only provide the optimal amount of lighting throughout a building but also save energy and money.
LEDs also help lower electricity costs in exterior lighting systems. Those used in parking lots, garages, and walkways can be configured to automatically dim or turn lights off when sensors detect an unoccupied area, and much faster than today’s systems. This type of automation is an especially attractive cost-saving option for cities. About half of a city’s monthly electricity budget is devoted to keeping the streetlights on.
Other Benefits  
LEDs also are changing the way architects and interior designers use lighting. Because the bulbs are smaller and weigh less than traditional ones, LED products allow for greater flexibility and creativity in lighting venues such as concert halls, museums, and retail stores, where aesthetics are especially important, while reducing energy usage.
LEDs in malls can motivate people to linger in a store longer and therefore boost sales. The ability to adjust from warmer to cooler shades of white, referred to as color tuning—along with precise light distribution—allows the retailer to create an inviting space that could appeal to the shopper’s sense of comfort, safety, and familiarity. In the home, LED lights could automatically mimic a bright, sunny day even if it is gloomy out. Such lighting systems will allow us to adjust our environments in ways that older technologies never could.
High Upfront Cost
Although LED prices have dropped dramatically, and continue to do so as technology advances, they typically cost more than other lighting systems. However, their high level of efficiency means you can recoup your upfront costs in a relatively short period of time. Besides requiring less electricity, LED’s long lifespan also saves you money on maintenance and replacement bulbs,  .
 Advantages:
The U.S. Department of Energy sees LEDs as the lighting source with the greatest potential for the future. They predict that, with widespread adoption of LEDs, by 2025 the country will:
·         Lower electricity demands for lighting by 62%.
·         Reduce carbon emissions by 258 million metric tons.
·         Diminish amount of materials in landfills.
·         Prevent construction of 133 new power plants.
·         Save $280 billion.
Although LEDs aren’t practical for every application (yet), they are certainly the lighting choice of the future and offer huge benefits, including energy savings, for your facility and the country as a whole.
LEDs have many advantages over incandescent light sources, including lower energy consumption, longer lifetime, improved physical robustness, smaller size, and faster switching. They are also significantly more energy efficient and, arguably, have fewer environmental concerns linked to their disposal.
Benefits of LEDs and IREDs, compared with incandescent and fluorescent illuminating devices, include: Low power requirement,  Most types can be operated with battery power supplies; High efficiency Most of the power supplied to an LED or IRED is converted into radiation in the desired form, with minimal heat production; Long life When properly installed, an LED or IRED can function for decades.
The evolution of LEDs as a source of white light has progressed dramatically in the last two decades, especially in terms of efficacy, or how well a light source produces visible light, measured in output lumens/input watts. The increase in efficacy has been achieved primarily through advances in LED chip technology, and is helping to drive LED adoption. LED products are also more affordable than incandescent bulbs over their life cycle, because their power requirements are lower and the bulbs themselves can last more than 10 years, compared with today’s incandescent bulbs they are replacing, which often last up to a year or so. Advntgaes of LEDs include:

-Energy efficient source of light for short distances and small areas. The typical LED requires only 30-60 milliwatts to operate
-Durable and shockproof unlike glass bulb lamp types
-Directional nature is useful for some applications like reducing stray light pollution on streetlights
Disadvantages:

-May be unreliable in outside applications with great variations in summer/winter temperatures, more work is being done now to solve this problem
-Semiconductors are sensitive to being damaged by heat, so large heat sinks must be employed to keep powerful arrays cool, sometimes a fan is required. This adds to cost and a fan greatly reduces the energy efficient advantage of LEDs, it is also prone to failure which leads to unit failure
-Circuit board solder and thin copper connections crack when flexed and cause sections of arrays to go out
-Rare earth metals used in LEDs are subject to price control monopolies by certain nations
-Reduced lumen output over time

Efficiency
Typical indicator LEDs are designed to operate with no more than 30–60 milliwatts (mW) of electrical power. Around 1999, Philips Lumileds introduced power LEDs capable of continuous use at one watt. These LEDs used much larger semiconductor die sizes to handle the large power inputs. Also, the semiconductor dies were mounted onto metal slugs to allow for greater heat dissipation from the LED die.
One of the key advantages of LED-based lighting sources is high luminous efficacy. White LEDs quickly matched and overtook the efficacy of standard incandescent lighting systems. In 2002, Lumileds made five-watt LEDs available with luminous efficacy of 18–22 lumens per watt (lm/W). For comparison, a conventional incandescent light bulb of 60–100 watts emits around 15 lm/W, and standard fluorescent lights emit up to 100 lm/W.
As of 2012, Philips had achieved the following efficacies for each color. The efficiency values show the physics – light power out per electrical power in. The lumen-per-watt efficacy value includes characteristics of the human eye and is derived using the luminosity function.

Color
Wavelength range (nm)
Typical efficiency coefficient
Typical efficacy (lm/W)
620 < λ < 645
0.39
72
610 < λ < 620
0.29
98
520 < λ < 550
0.15
93
490 < λ < 520
0.26
75
460 < λ < 490
0.35
37

Red and Infrared LEDs are made with gallium arsenide
Bright Blue is made with GaN -
gallium nitride
White LEDs are made with 
yttrium aluminum garnet
There are also orange, green, blue, violet, purple, ultraviolet LED

In September 2003, a new type of blue LED was demonstrated by Cree. This produced a commercially packaged white light giving 65 lm/W at 20 mA, becoming the brightest white LED commercially available at the time, and more than four times as efficient as standard incandescent. In 2006, they demonstrated a prototype with a record white LED luminous efficacy of 131 lm/W at 20 mA. Nichia Corporation has developed a white LED with luminous efficacy of 150 lm/W at a forward current of 20 mA. Cree's XLamp XM-L LEDs, commercially available in 2011, produce 100 lm/W at their full power of 10W, and up to 160 lm/W at around 2 W input power. In 2012, Cree announced a white LED giving 254 lm/W, and 303 lm/W in March 2014. Practical general lighting needs high-power LEDs, of one watt or more. Typical operating currents for such devices begin at 350 mA.

These efficiencies are for the light-emitting diode only, held at low temperature in a lab. Since LEDs installed in real fixtures operate at higher temperature and with driver losses, real-world efficiencies are much lower. United States Department of Energy (DOE) testing of commercial LED lamps designed to replace incandescent lamps or CFLs showed that average efficacy was still about 46 lm/W in 2009 (tested performance ranged from 17 lm/W to 79 lm/W).