ABOUT LAKE CHAD

Lake Chad is one of the largest inland lakes in Africa. It is believed to be a remnant of an inland sea. Geologica evidences show that this lake has changed its size several times in the past 12000 years. Its area was about 400000 sq kilometers in 4000 BC.The name Chad is a local word meaning "large expanse of water," in other words simply "lake." In 1823 the lake was first surveyd by the Europeans. This lake is shared by four african nations: Chad, Cameroon, Niger, and Nigeria. 20 million people of these nations live around this lake. Though this lake covers a large area its depth is very shallow to the extent of 10.5 metres.
In the 1960s it had an area of more than 26,000 km², making it the fourth largest lake in Africa. By 2000 its extent had fallen to less than 1,500 km². This is due to reduced rainfall combined with greatly increased amounts of irrigation water being drawn from the lake and the rivers which feed it, the largest being the Chari/Logone system,

Due to shrinkage of the lake water crisis has developed in the surrounding countries. This has developed serious conflict among the sharers of the lake. Farmers and herders want the water for their crops and livestock and are constantly diverting the water. The fishermen however want the remaining water in the lake to stay for their fishing.

Source : wikipedia.org
Image: ShrinkingLakeChad-1973-1997 Courtesy: NASA

Africa's Lake Chad Shrinks By 20 Times Due To Irrigation Demands, Climate Change

Africa's Lake Chad Shrinks By 20 Times Due To Irrigation Demands, Climate Change

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DRINKING WATER CRISIS IN SOUTH AFRICA

Drinking Water Crisis in South Africa - What You Don't Know Can Hurt You Badly
By Michael W Jones

Since 1948 our water quality has been steadily declining. In those days pollution was not an issue and post war expansion and industrialization took off at a rapid pace.Little thought was given to pollution controls in the future and by the time we did wake up we were in crisis where we still are today.

Water distribution networks are over-worked and crumbling, insufficient money , not enough political will , general apathy from local municipalities and insufficient skills in the water industry are driving us to disaster . Water Guidelines instituted in late 1996 are really inadequate, compared to overseas and First World countries. Some contaminants allowed in South Africa, such as Arsenic are up to 10 times the allowable levels designated threatening by the Environmental Protection Agency in the USA and Europe.

Contamination is just one of a myriad of problems. The major chemicals used in the treatment of water, ( Chlorine, Aluminum & Fluoride) have such bad side effects that one wonders whether we are not better off taking our chances with the water. Tests done in the USA have found a direct link between chlorine and cancers of the bladder , liver, pancreas, colon , rectum and urinary tract. Used in the Great War of 1914 & World War II as a chemical warfare agent, it is still used in gas form and pumped into the water supplies to kill cells. In this case bacteria causing Diphtheria and Cholera etc and it is very good at what it does. When last did you hear of an outbreak of Cholera ?

Problem is, Chlorine can not differentiate between living cells and bacteria so you and your family are on it's hit list, albeit unknowingly. Aluminum or Aluminum as it is termed here in Southern Africa is just as bad having being linked to senility, senile dementia and Alzheimer's disease.

Fluoride - heaven forbid they introduce that here, is a killer if not controlled very carefully. 1 part per million is beneficial to suppress tooth-decay and cavities in children only, 2 parts per million is poisonous. For everyone else it is merely another poison to digest and deal with.

pH levels and soft corrosive water cause huge damage not only to distribution networks but to consumers metal plumbing, piping, heaters, kettles and geysers.

Ongoing studies at the University of Cape Town for the last 7 years in conjunction with the Council for Scientific & Industrial Research and the Water Research Commission have resulted in limited success and small pilot projects. For the homeowner few solutions are inexpensive . Water Treatment companies hold all the cards and they sure know how to charge!

We drive through the beautiful Garden Route and admire the many rivers which look so "naturally clean " dark from the source and plant life, high in the mountains and catchment area, not realizing that that "darkness" is the cause of many a heart-ache. The water is loaded with tannic acids from our beautiful flora known as the Fynbos, for which the South African is world famous.

Tannins are one of the most difficult substances to eradicate causing brown stains on clothes during washing and staining cisterns , toilet bowls and basins. When in combination with other water elements such as low ph , iron or manganese they become almost impossible to eradicate. Water filters last but 6 weeks before having to be changed . This insidious substance is more like a dye stuff than a particle and penetrates everything.

Michael J runs a successful Water Filter distribution company in South Africa and is particularly active in the Western Cape Coastal area. Having acted as technical & sales trainer for larger water filtration & wholesale suppliers he is qualified both in practical and theoretical experience to advise on numerous water related conditions in South Africa and abroad.

Aqua-elite supplies not only South African home owners with equipment but also numerous African countries , parts of the USA, UK, Holland and clients in Dubai. Customized systems are available for the frequent traveler and can be built-into 4x4 vehicles, R.V's or even hand luggage. Visit our website & blog for in depth information on matters water related http://www.aqua-elite.com and
specialized information is available for the aspirant water bottler at http://www.nbws.org

Article Source: http://EzineArticles.com/?expert=Michael_W_Jones
http://EzineArticles.com/?Drinking-Water-Crisis-in-South-Africa---What-You-Dont-Know-Can-Hurt-You-Badly&id=1052894

ARSENIC AND FLUORIDE IN GROUNDWATER

Arsenic Contamination
Groundwater in a large part of the Bengal Basin contains high levels of arsenic. Large number of people of India and Bangladesh are compelled to drink water having arsenic concentration above the permissible limit.

At present, the primary source of drinking water in rural areas is the private domestic tube wells, which withdraws water from shallow aquifers (50 to 200 ft). Data from different sources indicate high arsenic content in water from such shallow aquifers in extensive areas in the delta. However, in many areas the deeper (> 500 ft) aquifers too show arsenic content above the permissible limit of 0.05 mg/litre according to the Indian standards.

Several countries in the world suffer from arsenic contamination of groundwater. The highest magnitude of this contamination is seen in Bangladesh and West Bengal. But in other parts of the world, e.g. Mongolia, Brazil, United States, Argentina, Ghana, Nepal, Pakistan etc are worst effected. In India, arsenic contamination is reported from Bihar, Uttar Pradesh, Madhya Pradesh, Tripura and Assam.

Arsenic Toxicity
Acute: severe abdominal pain, fever, cardiac arrhythmia.
Chronic: muscle weakness and pain, gross edema, Gastrointestinal disturbances, liver and kidney damage, swelling of peripheral nerves (neuritis), paralysis, liver injury, jaundice, peripheral vascular disease - blackfoot disease. Chronic drinking water exposure causes cancer (skin, lung and other organs).

Fluoride Contamination
Fluoride is another toxic material generally present in ground water. Prolonged drinking of water containing high fluoride may cause degeneration of bone and teeth. This is called fluorosis. About 300 people from the village of Nasipur (with a population of about 2000) in Birbhum, have been paralysed after drinking water contaminated with fluoride. According to media report, the local residents claim that the number is more than 1200. Investigations have proved that the fluoride content in Nasipur's water is 14 ppm, against the permissible limit of 1 to 1.5 ppm. There are other districts in West Bengal where fluoride is also found in groundwater.

Fluoride contamination in groundwater is not new in India. Fluoride above toxic limit is found in groundwater of many states like Jharkhand, Assam, Meghalaya, Madhya Pradesh, Orissa, Chhattishgarh, Tamil Nadu, and Andhra Pradesh. In West Bengal presence of fluoride in groundwater has been detected in the year 1998 by the State Water Investigation Directorate, West Bengal. It was found that in a single village of Birbhum district about 2000 people fell victim of the contamination.

Fluoride is readily incorporated into the crystalline structure of bone, and accumulates over time. The condition of fluoride poisoning is called skeletal fluorosis which increases risks of bone fracture. Skeletal fluorosis is a bone and joint condition associated with prolonged exposure to high concentrations of fluoride. Fluoride increases bone density and causes changes in the bone that lead to joint stiffness and pain.

Arsenic and fluoride contamination in groundwater are geogenic in nature. Detection of contamination through hydrogeological investigation is the only preventive measure.

WATER CRISIS IN PURULIA

WAter crisis in Purulia district is not new. Every year some parts of this district face severe water crisis during the summer. But whenever drought or similar situation arrives the development authorities oft for sinking tubewells in the affected area. But while sinking such tube wells attention should be given to the hydrogeological condition of the district. This district is mainly a granitic terrain consisting of crystalline basement rocks thinly covered with weathered mantle. There is a shallow fracture zone. This thin porous medium can not store sufficient quantity of groundwater. So most of the tube wells fail to yield water for a long time. It is always wise to opt for harnessing rainwater on the surface. Here is a high resolution hydrogeological map of Purulia.

RAINWATER HARVESTING IN KOLKATA MUNICIPAL CORPORATION AREA

INTRODUCTION: Kolkata is now a great megalopolis with about ten million populations. This city is not only growing in size but also growing in population day by day. This growth of population has cast a great impact on the land on one hand and on the other hand the demand for drinking water has grown by many folds.

The history of Kolkata water supply starts from the initiation of the British settlement in 1717 and runs up to 1870 when Calcutta Municipality was establish. During the various phases of formation of Calcutta municipality, topmost priority was given to water supply problems. The water supply of the newly constituted municipality commenced in the year 1870 with a 6 mgd plant at Palta. To cope with the increasing demand of portable water, the capacity of the water treatment plant was augmented in stages. In addition, there is 60 mgd of unfiltered water supply and ground water supply of 22 mgd by 260 deep tube wells.

At the increase in demand of water more and more hand tube wells were installed during the last two decades. Apart from private initiative the corporation has also installed a number of deep tube wells fitted with hand pumps.

The actual number of private deep tube wells is yet to be known. But withdrawal of ground water has increased to a great extent during the last two decades. This unaccounted has developed two major groundwater problems: -

a) Depletion of water level to the tune of 10-12mbgl at places.
b) Deterioration of water quality.

Geologically and geomorphologically Kolkata belongs to the lower deltaic plain of the Ganga-Padma river system.. The surface material is clay and clay loam. This clay extends up to a depth of 10 to 25 m bgl in most of the area. Below this clay bed a fine sand bed is found which extends up to a depth of 30-to 35-metre bgl. Below this level another clay, dark brown to grayish brown in colour occur up to a depth of 60 to 100-metre bgl. From this depth another sand zone occur which comprises of fine, medium and coarse sand and extends up to a depth of 120 to 180 metre bgl. Below this sand zone gravel bed occurs. Tertiary black and sticky clay occurs at the bottom of the sand and gravel zone.

Due to unique geological setting rainfall in Kolkata does not percolate downwards to recharge the groundwater regime. Rainwater is totally wasted and poses a serious problem like water logging and sewage overload.

The demand of water for domestic purpose in Kolkata is increasing day by day. The municipal water supply to some extent and private domestic water supply in some areas also depend on ground water. Since Kolkata is not within the groundwater recharge zone and the withdrawal of groundwater is very high in comparison with the groundwater recharge from remote area groundwater level has already depleted to a great extent. Recent studies have revealed that groundwater level of Kolkata has already gone down to 10 to 13 metre below sea level. .

To combat all the problems related to the water supply and demand, and also for the problems developed due to over withdrawal of groundwater scientists are advising to utilize rainwater in urban areas.

BENEFIT: Rainfall in Kolkata occurs during the monsoon. Maximum rainfall occurs from June to October. The average annual rainy days are 60. Average daily rainfall is about 30 mm considering only the rainy days. The monthly average rainfall is given below.

The volume of total annual rainfall in Kolkata over a 184 sq km area is 1.402X 184= 258 million cubic metres. This amount of water is required for 10 million people for 151 days. In the same way rainwater available on a 100 sq metre roof is 1.402 X 100 cubic metre annually= 140200 litres. This is enough for a family of five for 140 days.

PRACTICAL VIEW

It will never be possible to harness all available rainwater through any type of harvesting system. Moreover the water requirement of Kolkata is much higher than the amount of rainfall falling directly overhead. So Kolkata will remain dependant on the transported water from upstream regions. But rainwater harvesting in Kolkata has three visible benefits.

1) If a large amount of rainwater is used for groundwater recharge it will supplement the natural recharge to some extent.
2) If about 10% of rainwater is harvested properly through some well managed system in specific locations it will significantly reduce water logging during storm seasons.
3) If rainwater is harvested by individuals or by community housing societies the consumption of piped water will be reduced to a great extent. The Loreto Day School in Sealdah is utilizing rainwater for its toilets and significantly reduced municipal water consumption.