The New Nation - Internet Edition

History of dam failures

A few case histories of dam failures in India and in USA are described briefly below. The details regarding other failures are reported by Mahesh Kumar (1992) and Singh. Kaddam Project Dam, Andhra Pradesh, India Built in Adilabad, Andhra in 1957 - 58, the dam was a composite structure, earth fill and/or rock fill and gravity dam. It was 30.78 m high and 3.28 m wide at its crest. The storage at full was 1.366 108 m3. The observed floods were 1.47 104 m3/s. The dam was overtopped by 46 cm of water above the crest, inspite of a free board allowance of 2.4 m that was provided, causing a major breach of 137.2 m wide that occurred on the left bank. Two more breaches developed on the right section of the dam. The dam failed in August 1958. Kaila Dam, Gujarat, India The Kaila Dam in Kachch, Gujarat, India was constructed during 1952 - 55 as an earth fill dam with a height of 23.08 m above the river bed and a crest length of 213.36 m. The storage of full reservoir level was 13.98 million m3.

The foundation was made of shale. The spillway was of ogee shaped and ungated. The depth of cutoff was 3.21 m below the river bed. Inspite of a freeboard allowance of 1.83 m at the normal reservoir level and 3.96 m at the maximum reservoir level the energy dissipation devices first failed and later the embankment collapsed due to the weak foundation bed in 1959. Kodaganar Dam, Tamil Nadu, India This dam in the India, was constructed in 1977 on a tributary of Cauvery River as an earthen dam with regulators, with five vertical lift shutters each 3.05 m wide. The dam was 15.75 m high above the deepest foundation, having a 11.45 m of height above the river bed. The storage at full reservoir level was 12.3 million m3, while the flood capacity was 1275 m3/s. A 2.5 m free board above the maximum water level was provided. The dam failed due to overtopping by flood waters which flowed over the downstream slopes of the embankment and breached the dam along various reaches. There was an earthquake registered during the period of failure although the foundation was strong. The shutters were promptly operated during flood, but the staff could only partially lift the shutters, because of failure of power.

Although a stand-by generator set was commissioned soon, this could not help and they resorted to manual operation of shutters. Inspite of all efforts, water eventually overtopped the embankment. Water gushed over the rear slopes, as a cascade of water was eroding the slopes. Breaches of length 20 m to 200 m were observed. It appeared as if the entire dam was overtopped and breached. Machhu II (Irrigation Scheme) Dam, Gujarat, India This dam was built near Rajkot in Gujarat, India, on River Machhu in August, 1972, as a composite structure. It consisted of a masonry spillway in river section and earthen embankments on both sides. The embankment had a 6.1 m top width, with slopes 1 V :3 H and 1 V : 2 H respectively for the upstream and downstream slopes and a clay core extending through alluvium to the rocks below.

The upstream face had a 61 cm small gravel and a 61 cm hand packed riprap. The dam was meant to serve an irrigation scheme. Its, storage capacity of 1.1 108 m3. The dam had a height of 22.56 m above the river bed, a 164.5 m of crest length of overflow section, and a total of 3742 m of crest length for the earth dam. The dam failed on August 1, 1979, because of abnormal floods and inadequate spillway capacity. Consequent overtopping of the embankment caused a loss of 1800 lives. A maximum depth of 6.1 m of water was over the crest and within two hours, the dam failed. While the dam failed at a peak discharge of 7693 m3/s, the figure was revised to 26,650 m3/s after failure, with a free board of 2.45 m given, providing also an auxiliary spillway with a full capacity of 21,471 m3/s. The observed actual flood depth over spillway crest was 4.6 m with an observed 14,168 to 19,835 m3/s, while the design depth over spillway crest was 2.4 m. Nanaksagar Dam, Punjab, India Situated in Punjab in northwestern India, the dam was constructed in 1962 at Bhakra, with a reservoir capacity of 2.1 106 m3. An estimated maximum discharge of 9,711 m3/s had occurred on August 27, 1967, due to heavy monsoon rains that were heaviest in twenty years.

This caused dam to fail. The water that gushed through the leakage created a 7.6 m breach, which later widened to 45.7 m. The condition of the reservoir had worsened, causing a 16.8 m boil downstream of toe, which was responsible for the settlement of the embankment. As the dam was overtopped, causing a breach 150 m wide. A downstream filter blanket and relief wells were provided near the toe but were insufficient to control the seepage. The relief wells each 50 mm in diameter were spaced at a distance of 15.2 to 30.4 m. Panshet Dam: (Ambi, Maharashtra, India, 1961 - 1961) The Panshet Dam, near Pune in Maharashtra India, was under construction when the dam had failed. It was zoned at a height of 51 m and having an impervious central core outlet gates located in a trench of the left abutment and hoists were not fully installed when floods occurred at the site of construction. The reservoir had a capacity of 2.70 million m3. Between June 18 and July 12, 1961, the recorded rainfall was 1778 mm. The rain caused such a rapid rise of the reservoir water level that the new embankment could not adjust to the new loading condition. The peak flow was estimated at 4870 m3/s .

Water rose at the rate of 9 m per day initially, which rose up to 24 m in 12 days. Due to incomplete rough outlet surface the flow through was unsteady which caused pressure surges. Cracks were formed along the edges of the right angles to the axis of the dam causing a subsidence of 9 m wide. An estimated 1.4 m of subsidence had occurred in 2.5 hours, leaving the crest of the dam 0.6 m above the reservoir level. Failure was neither due to insufficient spillway capacity nor due to foundation effect. It was attributed to inadequate provision of the outlet facility during emergency.

This caused collapse of the structure above the outlets. Khadakwasla Dam (Mutha, Maharashtra, India, 1864 - 1961) The Khadkawasla Dam, near Pune in Maharashtra, India was constructed in 1879 as a masonry gravity dam, founded on hard rock. It had a height of 31.25 m above the river bed, with a 8.37 m depth of foundation. Its crest length was 1.471 m and had a free board of 2.74 m. The dam had a flood capacity of 2,775 m3/s and a reservoir of 2.78 * 103 m3. The failure of the dam occurred because of the breach that developed in Panshet Dam, upstream of the Khadkawasla reservoir. The upstream dam released a tremendous volume of water into the downstream reservoir at a time when the Khadkawasla reservoir was already full, with the gates discharging at near full capacity. This caused overtopping of the dam because inflow was much above the design flood. The entire length of the dam spilling 2.7 m of water. Vibration of the structure was reported, as the incoming flood was battering the dam. Failure occurred within four hours of the visiting flood waters. Tigra Dam: (Sank, Madhya Pradesh, India, 1917 - 1917) This was a hand placed masonry (in time mortar) gravity dam of 24 m height, constructed for the purpose of water supply. A depth of 0.85 m of water overtopped the dam over a length of 400 m. This was equivalent to an overflow of 850 m3s-1 (estimated).

Two major blocks were bodily pushed away. The failure was due to sliding. The dam was reconstructed in 1929. Teton Dam, Teton river canyon, Idaho, USA, NA - 1976 The construction began in April, 1972, and the dam was completed on November 26, 1975. The dam was designed as a zoned earth and gravel fill embankment, having slopes of 3.5 H : 1 V on the upstream and 2 H : 1 V and 3 H : 1 V on the downstream, a height above the bed rock of 126 m, and a 945 m long crest. The dam had a height of 93 m, a crest width of 10.5 m, and had side slopes of 1 V : 3 H on the upstream side and 1 V : 2.5 H on its downstream side. It had a reservoir capacity of 3.08 * 108 m3. The embankment material consisted of clayey silt, sand, and rock fragments taken from excavations and burrow areas of the river's canyon area. It had a compacted central core. Narrow trenches 21 m deep, excavated in rock and compacted with sandy silt and a deep grout curtain beneath a grout cap the central zone were the measures taken to control the foundation seepage. The dam failed on June 5, 1976, releasing 308 million m3 of reservoir water. A flood at an estimated peak discharge in excess of 28,300 m3/s had occurred. The peak outflow discharge at the time of failure was 4.67 * 104 m3/s. A breach 46 m wide at its bottom and 79 m deep had formed. The time of failure was recorded as four hours.

The cause of failure was attributed to piping progressing at a rapid rate through the body of the embankment. The two panels that investigated into the causes of failures were unanimous in agreement that the violence and extent of failure completely removed all direct evidence of the details and sequence of failure.

However, the main findings suggested that erosion on the underside of the core zone by excessive leakage through and over the grout curtain was the cause of destruction. "Wet seams" of very low density in the left abutment extended into the actual failure area. These caused local deficiencies in the compaction of the fill, and might have been the locus of the initial piping failure.

Earlier on the day of failure, leaks were observed about 30 m below the top of the dam. After four hours, efforts to fill the holes failed and the dam breached by the noon time. The fundamental cause of failure was regarded as a combination of geological factors and design decisions, which taken together allowed the failure to occur. Numerous open joints in abutment rock and scarcity of more suitable materials for the impervious zone were pointed out by the panel as the main causes for the failure of the dam. Futhermore, complete dependence on deep dry key trenches that developed arch action, cracking and hydraulic fracturing as a measure adopted against seepage and reliance on compacted material for impervious zone were also attributed as possible causes of failure.

Malpasset Dam An arch dam of height 66 m, with 22 m long crest at its crown. When the collapse occurred, the dam was subjected to a record head of water, which was just about 0.3 m below the highest water level, resulting from 5 days of unprecedented rainfall. The failure occurred as the arch ruptured, as the left abutment gave away. The left abutment moved 2 m horizontally without any notable vertical movement.

The water marks left by the wave revealed that the release of water was almost at once. The volume of water relieved was 4.94 Mm3 of water. 421 lives were lost and the damage was estimated at 68 million US dollars. Vaiont Dam This is an arch dam, 267 m high. During the test filling of the dam, a land slide of volume 0.765 Mm3 occurred into the reservoir and was not taken note of. During 1963, the entire mountain slide into the reservoir (the volume of the slide being about 238 Mm3, which was slightly more than the reservoir volume itself).

This material occupied 2 km of reservoir up to a height of about 175 m above reservoir level. This resulted in a overtopping of 101 m high flood wave, which caused a loss of 3,000 lives.

Baldwin Dam This earthen dam of height 80 m, was constructed for water supply, with its main earthen embankment at northern end of the reservoir, and the five minor ones to cover low lying areas along the perimeter. The failure occurred at the northern embankment portion, adjacent to the spillway (indicated a gradual deterioration of the foundation during the life of the structure) over one of the fault zones.

The V-shaped breach was 27.5 m deep and 23 m wide. The damages were estimated at 50 million US dollar. Hell Hole Dam The Hell Hole (lower) dam was a rock fill dam of height 125 m, failed during construction, when the rains filled the reservoir to an elevation of 30 m above the clay core. The capacity of this multipurpose reservoir after completion was 2.6 M m3.

(Source: Waterwatch. History of Dam Failures Prof. B.S. Thandaveswara Indian Institute of Technology Madras)

Land degradation threatens dryland populations

The survival of more than 250 million people living in the drylands of the developing world is being threatened by a chronic problem - land degradation.

Drylands cover about 41% of the earth's surface. The poor people in the drylands depend mainly on rainfed agriculture and natural rangelands for their survival. Their livelihoods are at risk due to land degradation, which is exacerbated by increasing population growth that is putting considerable pressure on fragile land resources.

However, science-based innovations can be mobilized to help arrest land degradation. The International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) headquartered in Patancheru in southern India, addresses the problem of land degradation through sustainable land management (SLM) techniques.

According to ICRISAT Director General Dr William D Dar, "Investing in SLM to control and prevent land degradation in the wider landscape is an essential and cost-effective way to deliver other global environmental benefits, such as maintenance of biodiversity, mitigation of climate change and protection of international waters".

ICRISAT is the executing agency and coordinator of the Desert Margins Program (DMP) funded by the Global Environment Facility (GEF). DMP is a collaborative initiative among nine sub-Saharan African countries - Botswana, Burkina Faso, Kenya, Mali, Namibia, Niger, Senegal, South Africa and Zimbabwe, which are assisted by five Centers supported by the Consultative Group on International Agricultural Research (CGIAR) and three advanced research institutes. The DMP focuses on better understanding land and biodiversity degradation and finding ways to counter them.

ICRISAT, jointly with a sister CGIAR Center the International Center for Agricultural Research in the Dry Areas (ICARDA) based in Syria, is catalyzing a global research program called 'Oasis' to intensify the effort against dryland degradation and desertification. Oasis brings the best global science partnerships to bear across Africa, Asia and Latin America.

To address the issue of poor soil fertility, some consider this a greater food-production constraint than drought in semi-arid Africa, ICRISAT has developed a "microdosing" technique that involves the application of small, affordable quantities of fertilizer with the seed at planting time or as a top dressing 3 or 4 weeks after emergence. This enhances fertilizer use efficiency and improves productivity.

The Institute is also testing two market development strategies to address constraints such as difficult access to fertilizer and credit; insufficient flow of information and training to farmers; and inappropriate policies. In West Africa, the 'Warrantage' or inventory credit system aims to resolve the farmers' capital constraint.

Farmers place part of their harvest in a local storehouse in return for loans, which they use to pay debts and start various income-earning activities to tide over the long dry season. The stored grain is sold later in the year when prices are high, and the farmer is able to repay the loan. ICRISAT has also succeeded in getting private fertilizer companies to sell fertilizers in small packs that smallholder farmers can afford.

The Institute has partnered with other organizations and has evolved a new consortium watershed management model to control land degradation and improve rural livelihoods. The approach is built on the principle of harnessing the strengths of the consortium partners for the benefit of all the stakeholders, and is based on a holistic systems approach called the Integrated Genetic and Natural Resource Management (IGNRM) strategy.

The Drylands Eco-farm (DEF) is an innovative trees-crops-livestock system for rainfed crop production. Fast-growing, drought tolerant Australian Acacias and a high value tree crop (Zizyphus mauritania) are intercropped with annual crops. It also incorporates principles of crop rotation, mulch application, windbreaks and nitrogen fixing trees. Profits from the DEF are 3-5 times higher than profits from current cropping systems.

The Institute is also undertaking Bioreclamation of Degraded Lands (BDL) project in barren, unproductive soils that are widespread in the West African Sahel. This combines simple effective techniques such as zaï holes, planting-basin cultivation, trenches and land scarification that concentrate limited water and nutrient resources close to the plant roots.

In addition the planting of high-value crops that restore organic matter and soil texture earn a handsome profit for the poor from fruit and gum trees, hardy leafy vegetables and legumes.

Besides developing and promoting these techniques to curb land degradation and improve the quality of agricultural soil, ICRISAT is putting great emphasis on strengthening the national capacities in studying climate, soil, vegetation and livestock trends and dynamics, standardization of methodologies to ensure data quality. It is also looking at building effective partnerships with national (NGOs, rural communities and CBOs), regional and international institutions and the private sector.

(Source: The International Crops Research Institute for the Semi-Arid Tropics (ICRISAT)

Can Indian Jamuna be brought back to life?

Money and expensive technology are not the solutions. We have already spent close to Rs 1,500 crore on cleaning the Yamuna -- and the river has become dirtier. New Delhi, April 18, 2007: Delhi has spent a whopping Rs 1,188-1,491 crore on cleaning the Yamuna till 2006. Or, Rs 71-85 crore per km in the 22-km stretch of the river as it passes through the city. But in spite of this massive investment, the river Yamuna runs dirtier.

"There is obviously something fundamentally wrong in the way we are managing our river cleaning programmes. Our planners believe in spending money without understanding the connection between sewage and its disposal and river pollution," said Sunita Narain, director, Centre for Science and Environment (CSE) here today. She was speaking at the release function of CSE's latest publication, Sewage Canal: How to Clean the Yamuna. The book was released by the Union minister for water resources, Saifuddin Soz and the chief minister of Delhi, Sheila Dikshit.

CSE also premiered a 32-minute video on the subject, Faecal Attraction: Political Economy of Defecation, which explodes various myths about river cleaning. "The film is our way of connecting the river to our water and sewage," says its director, Pradip Saha. Becoming dirtier all along "The Yamuna has become dirtier, and so have the towns along its stretch. And Delhi is its biggest polluter, followed by Agra, Ghaziabad and Faridabad. The Yamuna's 22-km stretch in Delhi is barely 2 per cent of the length of the river, but contributes over 70 per cent of the pollution load," said S V Suresh Babu, deputy coordinator, river pollution campaign, CSE.

Delhi, with only 5 per cent of the nation's urban population, has 40 per cent of India's sewage treatment capacity. Despite this huge investment, the Yamuna remains as dirty as ever. The river, in fact, is relatively clean till it enters Delhi at Wazirabad. It leaves the city transformed into a murky sewer. In Delhi, the river has virtually no freshwater for nine months. Delhi impounds all its water at Wazirabad, where the dammed up river practically ceases to exist; what flows subsequently is only sewage and waste from Delhi's 22 drains. There is just no water available to dilute this waste.

Pollution levels in the Yamuna have risen. BOD load has increased 2.5 times between 1980 and 2005 -- from 117 tonne per day (tpd) in 1980 to 276 tpd in 2005. Dissolved oxygen (DO) - to check if the river is alive -- in the upper segments, considered pristine, is dipping, indicating an increase in organic pollution. By the time the river is midway through Delhi, the total coliform count is so high that it is difficult to count the zeroes. Pesticides and heavy metals are also present in the river.

In fact, the river does not meet minimum standards for bathing even after treatment. There has been no change in pollution levels in Delhi from 1996. On April 10, 2001, the Supreme Court had directed that DO levels were to be maintained at a minimum concentration of 4 mg/l -- but five years after, the river is still dead.

It is clear that all the money spent to clean the Yamuna has literally flown down the drain, say the writers of Sewage Canal. In spite of that, in 2006, the Delhi government submitted another grand Rs 4,000 crore proposal under the Jawaharlal Nehru National Urban Renewal Mission. If approved, investment per km under this programme would be Rs 235-250 crore.

Investment not enough Pollution of the river is directly linked to the inefficient water planning and management in Delhi. Our planners have no clue about how much water the city uses, and neither do they know how much waste the city generates. It is not surprising, therefore, that the growth in sewage treatment capacity has not kept pace with the increase in population and waste. Treatment capacity has increased almost eight-fold in the last 40 years, but wastewater generation has grown 12-fold in the same period.

"We also suffer from under-utilisation. Delhi has a sewage treatment capacity of 2,330 mld -- 17 STPs -- of its own. But only 68 per cent of this capacity is utilised," says Suresh. The reasons are many: sewage has to be transported over long distances for treatment, through largely defunct conveyance systems. In 2001, only 15 per cent of Delhi's sewerage system was functional. On top of this, almost 45 per cent of Delhi lives in unauthorised colonies, generating 'illegal' sewage, which is unaccounted for.

The sheer mindlessness of Delhi's pollution control efforts is evident from one example: a major portion of whatever Delhi manages to treat is released back into the city's drains. This treated effluent mixes with untreated and 'illegal' waste flowing in from large parts of the city, thereby nullifying all efforts to clean it. Also, efforts at reuse have been completely insufficient, to say the least. According to the DJB, about 535 mld is supplied for reuse.

Needed: a Revival Action Plan "What we need is to maximise utilisation of the existing treatment facilities and ensure reuse of treated effluents," says Narain. All waste -- legal and illegal, sewered and unsewered -- must be trapped and treated and not mixed with untreated sewage. Centralised STPs cannot be the only option --- the cost of transporting waste to the treatment facility and transporting treated effluent back to the point of reuse makes them too expensive to run. Therefore, treatment facilities need to be constructed close to the source of sewage generation. Based on these principles, a detailed plan for the top six drains of the city, which contribute 90 per cent of the pollution in the river, should be made and implemented.

Simultaneously, steps should also be taken to achieve dilution in the river -- mainly by reducing the city's demand for freshwater. The river needs water for a minimum flow to keep it alive. Fiscal instruments - like taxing water-guzzling flush toilets -- can work. Simultaneously an attempt needs to be made to revive the waterbodies and their catchment areas to store maximum run-off, which could then be used for local water needs or could be released into the river for dilution. Says Narain, "We must remember that whatever amount of waste we manage to treat will be inadequate, and the technology to treat the waste is hugely expensive. It will be a battle which we will never win if we continue fighting it the way that we have been doing all this while. The only way out is to rethink our approach." The book and the film expose the political economy of defecation, where the rich are subsidised to defecate in convenience and the poor pay for pollution with their ill health because of dirty water. This is not acceptable, says CSE.

Global business leaders' climate change plan

Detailed climate change recommendations to the Group of Eight leaders, backed by an influential group of CEOs from many of the world's largest companies, were delivered on 20 June to Prime Minister Yasuo Fukuda of Japan, who will host the G8's annual summit next month in Hokkaido, Japan. The document outlines a new, more "environmentally effective and economically efficient" long-term policy framework to succeed the Kyoto Accord. It was presented on behalf of the group of 91 chairmen and CEOs by World Economic Forum Executive Chairman and Founder Klaus Schwab.

In their recommendations, the CEOs urge adoption of a rapid and fundamental strategy by governments to bring about a low-carbon world economy. They call on the G8 and other developed country governments to provide leadership through deep absolute cuts in their greenhouse gas emissions (GHG), as well as direct work with the international business community to develop a pragmatic strategy of cost-effective, medium-term carbon abatement opportunities.

Facilitated by the World Economic Forum and the World Business Council for Sustainable Development (WBCSD), the new policy framework recommended by the CEOs represents a significant departure from the structure of the 1997 Kyoto Accord - more flexible and more results-oriented.

The business leaders suggest a combination of "top-down" international commitments by governments, particularly by developed economies but also including emerging economies, and practical "bottom-up" efforts within and across industry sectors in the form of a multifaceted agenda of intensified public-private cooperation. These efforts will be aimed at speeding the development and diffusion of low-carbon technologies, mobilizing financial support to help developing countries adopt such technologies, spurring changes in consumer purchasing behaviour, and establishing common metrics to create a positive dynamic of improved corporate benchmarking, disclosure and investment decision-making with respect to GHG mitigation.

At the same time, business leaders urge adoption of both a long-term goal, such as the aspiration to at least halve global GHG emissions by 2050, and a series of clear intermediate targets to be achieved in the most cost-effective manner possible through the use of market mechanisms that create clear economic value from emission reductions, including a deep and liquid international market for carbon.

World Economic Forum Founder and Executive Chairman Klaus Schwab said: "The business community has a crucial contribution to make to the design of a more effective global strategy to combat global warming, and these business leaders are sending a clear message to governments that they are willing and able to engage with ideas and other support if invited to do so. Having reached consensus among leading firms from virtually every industry and region, they have given us a concrete vision of how the international community could construct a plan that is both environmentally and economically sound. I congratulate them for the pragmatic, can-do spirit with which they approached this initiative, which ought to be a source of inspiration for everyone, not least the G8 leaders who will meet in two weeks."

In a hopeful sign for the United Nations negotiating process that is due to culminate in December 2009 in Copenhagen, Denmark, CEOs of major companies endorsed the consensus recommendations in a wide range of developed and developing countries, including Australia, Brazil, Canada, China, India, Japan, Malaysia, Mexico, the Middle East, Russia and South Africa, as well as from Europe and the US. The group includes at least one CEO of a major company from each of the G8 and +5 economies, encompassing virtually every industry sector, such as energy, utilities, aviation, automotive, mining and metals, logistics, information and telecommunications, and financial services.

A multi-industry, cross-regional steering committee, including Alcoa, Applied Materials, AIG , Basic Elements, British Airways, Deutsche Bank, Duke Energy, EDF, Eskom, Petrobras, RusHydro, Shell, Telstra, Tepco, TNT and Vattenfall, led the development of the recommendations over the past 16 months.

The Pew Center for Global Climate Change served as a resource partner in the process to develop the recommendations, which involved over 500 participants in discussions in 11 meetings on five continents as part of the business contribution to the G8's Gleneagles Dialogue on Climate Change, Clean Energy and Sustainable Development. Involving 20 of the world's leading energy producing and consuming nations, the Gleneagles Dialogue was created as part of the outcome of the G8's 2005 summit hosted by then United Kingdom Prime Minister Tony Blair in Gleneagles, Scotland.