SCIENCE & TECHNOLOGY Thursday, August 7, 2003, Chandigarh, India

Coping with cloudbursts
D.N. Handa
ue to locational and geographical features, the hill State of Himachal Pradesh is one of the major disaster-prone states in the country in respect of earthquakes, flash floods triggered by cloudbursts, landslides, avalanches and forest fires.

Hair and nails are formed of dead cells, but both keep growing. Why?
The fact that hair and nails are made of dead cells does mean that these cells cannot exchange information. That is why you do not feel any pain when you cut your hair or trim your nails.

New products & discoveries

  • Dark energy ripping cosmos apart

  • Old worms, new aging genes




Coping with cloudbursts
D.N. Handa

Due to locational and geographical features, the hill State of Himachal Pradesh is one of the major disaster-prone states in the country in respect of earthquakes, flash floods triggered by cloudbursts, landslides, avalanches and forest fires. The recent cloudburst in the Gadsa area of the Kulu valley and resultant flash flood on July 16 in Pulia nallah has again brought on surface our unpreparedness, inadequacies and complacent attitude in disaster management.

While calamity of this kind is understandable in hills, it however soon became evident that the loss of lives could have been avoided had we learnt from number of such happenings in the past particularly in Satluj and Beas basins. Prominent among them were the massive and violent flash flood in the river Satluj during the night on July 31, 2000, cloudburst and flash flood in the Beas in September, 1995, and cloudbursts that wreaked havoc in Chirgaon in the Rohru and Wangtu areas in Kinnaur district in 1997.

A cloudburst is a devastating weather phenomenon representing sudden burst of highly concentrated rain associated with thunderstorm over a small geographical area. Cloudbursts are common to all hilly areas but the states of Himachal Pradesh and Uttaranchal etc. are most affected due to topographical conditions. Most of the damages to properties, communication system and human casualties are as a result of flash floods. The phenomenon occurs due to sudden upward drift of moisture-laden clouds as a tall vertical column termed "Cumulonimbus Clouds" usually associated with cloudbursts. The hilly terrain and heavy moisture contents facilitate rapid condensation and the cloud formation sheds its water load with ferocity over localised area with rainfall intensity as high as 100mm per hour. The flash floods are a growing concern in hills due to removal of trees and vegetation cover. The barren steep rocky slopes that absorb little water facilitate quick runoff. The factors affecting the runoff from a catchment area are:

i. Intensity, distribution and duration of rainfall.

ii. Area and shape of catchment both as to external boundary and internal drainage system.

iii. Slope of the catchment.

iv. Nature and permeability of the hill slope.

The intensity and duration of the cloudburst in the Gadsa valley was high, as it had been raining very heavily since the previous night. "Time of Concentration" at a particular point is time required for the water from the farthest part of drainage area to reach that point. If the storm lasts for a period more than this, the runoff will be maximum and devastating.

In hills there are many drainage courses along the steep slopes contributing lot of discharge to the main nallah. The water loaded with debris, boulders and uprooted trees moves down the steep hill slope with terrific speed and deadly noise destroying everything on its way.

The topography of the state enhances the devastation. It would be desirable for the hydel project authorities to realise that such happenings do occur in hills and take care of the possibilities of the risks these pose especially during construction. Nathpa Jhakri Hydel Project and some other projects have already experienced such events.

The unplanned construction of hydel projects, roads and large-scale mining/quarrying have put a severe strain on the delicate and fragile ecology of Himalayas gifted with lush green landscape and fascinating environment. With removal of forest and vegetative cover, the destructive action of water gets further pronounced. The excavated materials disposed of carelessly on hill slopes besides damaging the green cover, trees and agricultural land, are carried down during heavy rains causing siltation and consequent reduction in the storage capacity of the reservoirs.

Enormous quantity of soil and boulders is moving down from Largi hydel project causing siltation of the bed of the Beas and Pandoh Dam reservoir. The excavated debris should therefore be moved to selected locations to fill the depressions or to some safe outlets.

Too much human interference i.e. indiscriminate mining/quarrying along the bed of the Beas and even putting hurdles in its flow are responsible for the extensive damages suffered by the Kulu-Manali section of National Highway 21 during the unprecedented floods in the years 1993 & 1995.

The causes of such disasters thus are both natural and man made. Whereas nothing can be done about topographical, geological and geographical features responsible for calamities, the contributory factors by humans can certainly be identified and controlled to a great extent.

The large-scale deforestation, excavation and haphazard disposal of debris, boulders and rock fragments after blasting, therefore, need to be controlled and checked. Maximum stones from the excavated earth and rock cutting should be retrieved and stacked which will not only minimise the damage to the eco-system and limited agricultural land in hills but can also be fruitfully utilised in a cost-effective way on protective works.

Prevention begins with information and awareness. Public awareness and participation is therefore crucial in limiting the loss of life and public assets. On occurrence of such calamities, the response speed and its quality are of great importance in saving lives immediately. There is thus need to establish "Quick Reaction Teams" both at District level and State level to deal with such situations promptly.

Another suggestion is that insurance against calamities in high-risk zones, particularly in hydel projects, may be made compulsory for the workers. This will have an added indirect advantage of serving as a check on enforcing the safety measures, as insurance companies interested in limiting their liabilities will insist on certain minimum precautions and safety measures.

A senior level Labour Officer is also required to be posted in each project. Despite all precautions and man having no control over the nature, hazards will exist because human activities, deliberate or inadvertent, are responsible for such disasters.

We should, however, do our best well in advance.

The writer is a former Engineer-in-Chief, Himachal Pradesh P.W.D.



Hair and nails are formed of dead cells, but both keep growing. Why?

The fact that hair and nails are made of dead cells does mean that these cells cannot exchange information. That is why you do not feel any pain when you cut your hair or trim your nails. That is the reason that horse’s hoofs allow them to run on stony rough surfaces without being hurt or the claws of some animals, or beaks of birds and the horns of deer provide such useful appendages. The hair of a beautiful girl makes her more beautiful and the hair on the body of sheep keeps it insulated from the environments and, when shorn, allows us to make woolen clothes. Invention of the possibility of hair and nails was an intriguing and useful outcome of evolution. But these dead parts must also arise from locations that are alive.

In the case of nails, say on our fingers and toes, the insensitive part we see, and sometimes apply nail polish to, is called the nail plate. This plate is coupled to the skin at the bottom. This is called the nail bed. There is a matrix, a hidden part of the nail where the growth takes place. Nails do not grow at the end but from this matrix under the skin of the finger. This is called the cuticle. If you put a mark on your nail with indelible ink, you would see this mark travelling towards the end as time passes. The nail plate, even though made of dead cells, is continuously renewed at the rate of about a millimeter a week.

Hair is somewhat similar. The growth is at the follicles under the skin. The dead cells keep being added and the hair grows long. Both, the hair and the nails are made of dense, compacted proteins.

Ozone layer alone has the power to block the ultraviolet rays from sun. What is the reason?

Let me try to explain the drama of formation of the ozone layer and its role. Ozone is a molecule of oxygen with three atoms. These molecules are heavier than those of ordinary oxygen or nitrogen. Therefore one would expect that such a gas would be found closer to the ground and not at very high altitude! The reason for this anomalous phenomenon is that ozone is formed in the rare upper atmosphere and it is easily destroyed in collisions with other molecules and absorption of ultraviolet from the sun. It does not have enough time to diffuse down to the ground level. But how is it formed and why does it provide the essential shield against that part of the ultraviolet that would otherwise reach down to where we live? The answer to both these questions has to be understood together.

In order to make a molecule of ozone we need a free atom of oxygen that can come close to a molecule of ordinary oxygen and stick with it. Ultraviolet rays whose energy is high enough to break oxygen molecules into atoms produce these free atoms of oxygen. In the process such ultraviolet rays are themselves screened out - there is enough oxygen and other material in the atmosphere. Part of the ultraviolet that does not have sufficient energy to split oxygen atoms does not get shielded in this way. It can just scatter without harming the atoms on the way without being absorbed. This is precisely what would happen if there were no ozone. In ozone the oxygen atoms are not as strongly bound as in ordinary oxygen with three atoms to a molecule. Lower energy ultraviolet can peel off one of these atoms and in the process itself die. Thus we have a drama in which the ozone is created with the help of the high-energy ultraviolet and then becomes instrumental in shielding us from the low energy part of the ultraviolet spectrum of the sun! It is estimated that a molecule of ozone has a life of about three minutes. It is born high up in the atmosphere and in a short while dies while protecting us - a real martyr.


New products & discoveries

Dark energy ripping cosmos apart

Some of the colour differences in this temperature map of the cosmic microwave background, researchers say, result from a mysterious substance called dark energy
DARK FINGERPRINT. Some of the colour differences in this temperature map of the cosmic microwave background, researchers say, result from a mysterious substance called
 dark energy.

Astronomers have found new evidence for one of the strangest properties of the universe. A mysterious substance, dubbed dark energy, appears to be ripping the cosmos apart, causing the universe to expand at an ever-faster rate. The wrenching findings come from a correlation between two kinds of sky maps—one that denotes the positions of large numbers of galaxies and another, a snapshot of the cosmic microwave background, which is the remnant radiation from the Big Bang.

By comparing the maps, astronomers have found the imprint of dark energy, which pushes objects apart and thus counters gravity’s familiar tug. Previous support for dark energy has been based on the brightness of distant stellar explosions known as supernovas. With only one line of evidence, however, some researchers weren’t convinced.

"Since the implications of dark energy are so profound for physics, having multiple, independent lines of evidence for its existence is absolutely essential," says Joshua A. Frieman of the Fermi National Accelerator Laboratory in Batavia, Ill., a coauthor of one of four dark-energy studies recently posted online. Each study uses data from the Wilkinson Microwave Anisotropy Probe (WMAP), a satellite that is generating detailed maps of the cosmic microwave background .

This remnant radiation is riddled with hot and cold spots, most of which reflect the lumpiness of the infant universe, from which galaxies grew. But some of the energy in the hot spots may have been acquired later, as light travelled for billions of years to reach Earth.

During their long journey, photons from the microwave background encounter huge concentrations of matter, such as superclusters of galaxies. As the photons fall into these clouds of matter, they gain energy, like a marble that speeds up as it rolls downhill. As the photons climb out of these areas, they lose energy.

If the universe were flat — so that parallel lines never meet — and contained no dark energy, photons traversing matter-filled regions would gain exactly as much energy as they lose. But in a flat universe containing dark energy, there would be no such cancellation, says Frieman.

Old worms, new aging genes

For more than a decade, Cynthia Kenyon has watched microscopic worms of the species Caenorhabditis elegans live far longer than they should. She has seen mutant strains of this worm, which is normally dead and gone after a mere two or three weeks, last well into their second month. It’s as if a person lived to be 200 years old. Kenyon’s long-lived worms are a result of mutations in individual genes. That’s a radical notion to many scientists who have long thought of aging as an uncontrollable process of deterioration that isn’t regulated by single genes.

"There have to be genes that affect life span," counters Kenyon of the University of California, San Francisco. Noting the dramatic differences in life span among various animals — a mouse may last for 2 years while a bat can live for half a century — Kenyon has become convinced that longevity has evolved in animals many times. She argues that her long-lived nematodes can reveal some of the fundamental molecular biology that controls longevity in more-complex organisms, even people.

In 1993, Kenyon and her colleagues jump-started the field of aging genetics when they reported on a mutant strain of C. elegans that lives twice as long as normal. It showed the largest proportional lifespan extension of any animal known at the time.