My heart goes out to the families who have lost their dear ones during the recent unprecedented devastation in the north Indian state of Uttarakhand. The author is also saddened to see the damage to the landscape around the river systems, including private and public properties and infrastructure projects. The author has worked in the area and was there visiting projects during this very period a decade ago. It is going to take a long time to make a real assessment of the loss.
As is natural, people announce their snap judgements regarding the causes of this tragedy and question if the losses could have been mitigated–some out of extreme anger while others to demonstrate that their apprehensions have come true. It is intended for this article to explore the situation in a holistic manner without any bias.
It has to be well understood that the very formation of the Himalayas is entirely different than other mountains. They have been formed by the crust of the earth folding under great pressure resulting from the movement of the Indian Plate against the Tibetan Plateau. Consequently, the rocks are as varying as the crust of the earth that has gone into the formation of Himalayas. The Himalayan rocks are under great stress due to the folding.
The stresses get released now and then causing minor or major earthquakes and in the slippage of rock mass along faults, shear zones or other geological weaknesses. With excessive rain, the rock mass gets saturated and additional slippages, small and large, occur.
Historically, large slips have been occurring in the Himalayas either due to excessive rainfall or due to earthquakes. The great earthquake of 1950 caused immense damage to the Brahmputra Valley in the North Eastern Himalayas. At this time, no hydro electric projects had been constructed. The damages in the Brahmputra Valley and the river itself were unprecedented with the bed rising above bank levels at several places. Huge cracks capable of swallowing elephants had developed in the river bed. Then Prime Minister, Pandit Jawahar Lal Nehru, had rushed to Dibrugarh and called for the Flood Protection Embankment to be constructed for the safety of Dibrugarh before the next floods. The work was accomplished by the Central Water Commission. The extreme turmoil, into which the river Brahmputra was thrown, resulted in its behaving as a braiding river that has yet to settle down.
A very large slip in the Alaknanda Valley in 1970 caused heavy silt content in the discharge of the Ganga. Again, there were no hydro electric projects in the Ganga Valley at that time. There was hardly any addition to the existing roads. Improvements to the Delhi- Badrinath road, making it a national highway, came much later. Also, there was not any notable encroachment in the waterway of the riverine system and so only a little damage to the property occurred. The Upper Ganga Canal taking off from the Ganga at Haridwar was then the first Water Resources Project. Heavy siltation occurred in the Ganga Canal for several kilometres in the head reach, which had to be cleared well before the ensuing Rabi Irrigation. As the author was associated with the work, the author recalls what a massive project it was to be completed in a short period in those times. With that experience, the Ganga Canal was closed this time to avoid a repeat of the same.
In 1978, there were record damages due to floods all over the country. Most of the bridges across the river Teesta in Sikkim were washed away. There were no hydro power projects then on Teesta or its tributaries. The same year, there was a very large slip in the Bhagirathi valley near Bhatwari, much upstream of Uttarkashi and the then under-construction Maneri Bhali Hydro Electric Project Stage I, where the author was working. The slip caused a blockage of the river and water started getting impounded. A few days later when the blockage was washed off, huge discharge with a high wall of water gushed down causing damage to both the project and the town of Uttarkashi.
Himalayas not only have the maximum of water potential in the country but also have a maximum of hydro power potential. The growing needs of the society call for larger availability of energy, both for domestic and industrial usage. There are two types of sources of energy: ones that are capable of being replenished like hydro, wind, solar, etc., and the others that are limited, like coal, crude oil, gas, etc.
Thus far, among the former, hydro power is the most exploited source of energy, and for which our country has maximum of unexploited potential in the Himalayas.
Construction of hydro power projects in the Himalayas continues to be, wrongly or rightly, labelled as responsible for the damages in the area, both to the society and to the topography. There can be endless arguments for and against this thinking. However, in the wake of the recent disaster in Uttarakhand, it is proposed to examine the existing practices and possible improvement.
Hydro power as a source of energy is a necessity for society for reasons that it causes no or minimal damage to the environment. Even though it is capital intensive and has long gestation, it is still much cheaper than other sources. Commercially, also, it may not be prudent for the states having this potential, not to tap it. Otherwise, for India it shall mean a loss of possible availability of power that would have to be obtained from other sources not so favourable.
Speaking broadly, any project has the stages of Formulation, Construction, Operation and Maintenance and Decommissioning. Enough exercises are being carried out during the approvals of the projects to ensure that hydro power projects do not adversely affect the environment.
This incidentally, is one of the major reasons for the enormous delay in their approvals. Operation and Maintenance of hydro power projects have hardly been blamed for any adverse effects on the environment. Hydro power projects in the Country have yet not reached the stage of decommissioning as in the United States. It is the Construction of these projects which is labelled with a question mark. It is thus relevant to discuss the prevailing construction methodologies and the possible choices.
Typically, any hydro project comprises a barrier across the river–a barrage/dam; Intake work; a water conductor system– open channel, tunnel or combination of these and a power station–on surface or sub-surface with allied facilities.
The construction of these facilities requires construction of new access roads or at least improvement of the existing roads. As these projects are usually far away from towns, residential and non-residential buildings, mostly of temporary nature, must also to be constructed.
Excavation
Soon after the approval for a project is received with all the statutory clearances, construction of new access roads and the improvements to the existing roads, if required, is commenced basically involving excavation. After the lay out of the project components in the field, the first activity on the project is of excavation, may it be for the construction of the buildings or for the permanent works like the diversion structure, water conductor, power house, etc. Portals have to be established for adits, which also require open excavation. Thus excavation is the initial activity at site. It also results in an immediate change in the topography. Thus the excavation has to be planned and implemented with great caution, which is generally wanting.
1. Excavation for facilities and quarrying for construction material are very important activities having a major bearing on the environment. As mentioned above, open excavation is carried out for roads, dam/barrage, power channel, surface power house, appurtenant works and buildings. Sub surface excavation is carried out for intake works and tunnels. In projects where there is no space to locate the power house in the open or due to other considerations, sub surface excavation is carried out for the cavern to locate power house and appurtenant works. These activities as also the resultant disposal of muck are not given the desired consideration.
2. As a rule, presently the drill and blast method is adopted for hard and soft rocks. For surface and underground excavation, drilling rigs capable of high speed drilling longer holes for larger pulls are being increasingly deployed. Mostly, excessive charge is being used without any suitable design of the blasting pattern. Even if the blasting pattern is established after a few trials, it is seldom changed with the ever changing nature of rock in the Himalayas. This results in avoidable damage to the stability of slopes in open excavation and shock in the adjustment of stresses in rock mass around the excavated tunnels and caverns. The primary support system, after a pull for the excavation of tunnels, is delayed and stand-up time of the rock is usually exceeded. This results in immense redistribution of stresses in the adjoining rock mass which disturbs the stability of the entire rock mass. In the weak rock zones, there is enormous delay in the provision of final support system. The drill and blast technique has limitations under which the delay can at best be only minimised and not eliminated. In open excavation for roads or other facilities, blasting results in triggering of slope failures. The slope stabilisation is either avoided or delayed till such time it becomes unavoidable. It is felt that the drill and blast technique used in excavation should be stopped or taken up as an exception rather than as a rule. Alternative means of excavation such as road headers, should be used, and TBMs should be deployed in tunnel boring.
3. Excavation by rock hammers or road headers in the open may appear to result in slow progress but overall they are expected to provide timely completion of the job. There would be minimum slope failures. Thus there would be savings in time, which is lost in slope stabilisation. The over breaks would be minimal, so the problem of disposal of muck shall be reduced. In open excavation, blasting procedure requires that more land is acquired than actually needed to ensure that no damage takes place in the land not acquired. Several trees even outside the excavation area get damaged during blasting. Thus use of hammers and road headers will result in minimum interference with the environment.
4. TBMs provide a smooth excavation of the tunnel section. The rock can be provided with the final support immediately behind the boring so there is less disturbance to the rock mass. A TBM with a double shield is capable of handling very poor rock with no chance of the TBM getting stuck at the face. Himalayan geology does give surprises and such a TBM can bore through varying strata without hindrances. On one particular project, twin inclined bores at 30 degrees to the horizontal of length in excess of 1,500m each for the pressure shafts were bored timely without any hindrances with a double shield TBM. On the same project the open excavation for the power house, done by drill blast method, was hindered quite a lot due to repeated slope failures. Again with a TBM, the excavated muck is the bare minimum and so the problem of its disposal is also minimised.
5. Excavation at quarries for the production of coarse and fine aggregate for use in the works has to be very carefully planned. The identification of a suitable quarry, expected yield from the quarry, the working face(s), etc., all have to be very professionally planned. Construction companies very rarely deploy professionals with a mining background for this work. These matters are not given the due considerations. The consequences of bad judgement are enormous in the form of stripping avoidable foliage, felling of additional trees and the excess generation of muck.
Muck disposal
The muck generated in the construction of a project has to be suitably disposed. The basic principle to be kept in mind is that the area where the muck is disposed does not undergo a radical change in the existing land use pattern.
If it is a low lying area and serving as drainage, the drainage should not be blocked. If there is vegetation on the land, good soil should preferably be dumped there. If it is a land obtained on a lease, care should be taken that it is developed for future use.
1. The construction companies, large or small, pay only a little attention towards the disposal of muck. It is prevalent to dispose of the muck along the slopes of the river banks or even in the river bed. Such disposal of muck causes siltation in the river bed and is totally prohibited. Yet, this is done with impunity. This action by the construction company is, in my opinion, the single most irritant to the Project Affected People (PAP). Then it is no surprise that certain projects do not meet the concurrence of the PAP just because the earlier projects were constructed in this manner in complete disregard of the health of their river.
2. The rock that is either in excess of the requirement of the project or of quality that cannot be used in the works has to be suitably disposed. The first step is to ensure that muck is the bare minimum. The above mentioned suggestions shall contribute to minimise the muck generation.
3. The sequence of work should be so planned that the usable material obtained from the excavation is used in the works and resort to quarrying is minimised. Even at the cost of double handling, the usable excavated material should be consumed on the works.
4. Proper identification of disposal areas and their capacities should be carried out. Currently, this aspect is not being given due attention and decisions are taken when the excavation has already commenced. No excavation should be allowed to commence until its disposal area has been identified. There is always an acute shortage of suitable disposal areas. It is worth mentioning that for the disposal of silt taken out of the drains in Mumbai, the Corporation has incorporated a condition in the contracts that the contractor shall have to find the site of disposal himself. It can only be imagined as to what shall be the fate of the environment and the disposed muck that can be washed back into the drains during this very monsoon.
5. The designated disposal areas should be such that the disposal of muck shall not foul with the environment. It should be in low lying areas/valleys. The disposal should be carried out in a manner that the existing profile is retained with only an increase in elevation. The disposal should not interfere with the natural drainage. The practice of the dumpers unloading the muck directly in the disposal area and dozing it of should be stopped. The muck should be placed in a graded manner. Large boulders should go down and the voids blinded by spalls and soft rock/soil. Thereafter the muck should be rolled. This shall promote stabilisation of the muck and chances of its flowing down shall be minimised. This will encourage growth of vegetation and help in stability. The toe should have proper retaining wall with check walls in between the disposal area to avoid large scale slippage during rains. This should be done even if it requires handling of muck more than once.
Cost implications
1. Implementation of the above suggestions shall definitely increase the cost of the projects. With the norms being currently adopted in this sector, all the projects would lose the viability criterion. We shall have to change the way we assess the viability of these projects. The criterion should be based on the benefits that shall be reaped in areas where currently there is no power supply or if available is interrupted or lacks in quality (voltage/ power factor). Both tangible and intangible benefits including secondary and tertiary benefits should be included. The advantage of not requiring fossil fuel to be imported to that extent and the carbon credits being available should be included. These benefits compared with the cost should be the criterion.
2. As these projects are located in far flung areas, most of them need construction of new roads. Even where the roads exist, they may need major improvements. These roads are used by the public as well during construction of the projects and always thereafter. These roads facilitate development of tourism. It is not appropriate to charge the project for the cost of the roads. The cost of the access roads which are available for public use should be excluded from the cost of the project.
3. The change in excavation methodology would need rock breakers, road headers, tunnel boring machines and other allied equipment. Most of these shall have to be imported and would increase the cost of the projects. It may be recalled that there was a time when jack hammers were used for drilling in the drill blast method. However, in view of the performance efficiency of hydraulic drilling rigs, more and more projects have started using these. Some of the contracts even insist on the use of these rigs. Even these are imported machines but have become affordable. The same can be thought about the road headers and TBMs, etc. The more they are put to use, the more they are likely to get affordable. Currently, contractors do not want to own such machines for they are not sure of their future use and investment on these shall be blocked. Even the foreign companies that are providing these machines on a rental basis are not sure of their continued use in India and quote very high rates. We can certainly look in the future when, to start with, some of our enterprising companies can, in collaboration with foreign companies, start manufacturing units in India
Conclusions
1. Construction of hydropower projects in a manner as suggested above is likely to cause minimal interference with the stability of Himalayas. They shall also have minimal harmful effect on the environment.
2. The current damages in Alaknanda, Mandakini and Bhagirathi Valleys have been triggered by excessive and unprecedented rainfall in a short period in the river basins upstream of the hydroprojects. They may be categorized as ‘acts of God’ or ‘natural disasters’. As evidenced by the aforementioned events of 1950, 1970, and 1978, such extreme occurrences created havocs of unforeseen severities even without the existence of hydro projects. As such, in the case of current damages the hydro projects, in themselves, could not have contributed to the catastrophe in its entirety. In fact Tehri Hydro Project, which is a storage project, absorbed the excess discharge in the Bhagirathi and helped in saving towns of Rishikesh and Hardwar in the downstream.
3. Implementation of these suggestions shall require utmost discipline by the construction agencies during the process of excavation. Independent observers with authority to stop the work in case of violation of set norms should concurrently monitor. Not much purpose is served by imposing fines subsequently as the damage caused cannot be got undone. This shall win confidence and cooperation of the local population. This shall be helpful in the approval and execution of projects in the future.
