INTRODUCTION

Environment is defined as the surroundings in which we live. It has the living component  known  as  the  biotic  and  the  non -living  known  as  the  abiotic environment. In the living part all the plants animals, human beings, micro- organisms such as the bacteria, viruses, fungi etc. are there. In the non-living part the materials, temperature, humidity, air, soil, water, fire, energy, sky, noise, solar and other radiations are there.   All of these are in dynamic equilibrium with each other. Every action of the nature is cyclic. We have seen so many cycles like the material and nutrient cycles, hydrological cycle etc. These cycles are interrelated and the occurrence of one depends upon other also. As there is a dynamic interrelationship between the components of the environment, so nothing can be dealt in isolation and one has to think in a holistic manner. Holistic means considering others also alongwith ones development. The oriental practice was to worship the nature. Nature was respected. We felt gratitude to the nature for bestowing its unlimited uniform blessings upon us. The sun shines for each and every one of us with the same intensity. Every natural blessing is impartial and sufficient. It is sufficient for everybody’s need but not for anybody’s greed. Forgetting this basic fundamental theory, we have started exploiting the nature. Nature has some power to compensate the loss that is some adjustments it can do. But the situation has come where it has gone beyond its power of assimilation and it has started reacting. The global warming, earthquakes, Tsunami, Al-Nino and other calamities are the recent examples. Some of them may be natural phenomena but generally  it  is  the  human  beings  who  are  responsible  for  them.

NECESSITY OF ENVIRONMENTAL IMPACT ASSESSMENT

In the holistic and equitable development one takes care of others, means what so ever engineering project we plan or execute we consider its effect on the biotic and abiotic environment in which it is going to be implemented. This is known as environmental impact  assessment.

Forest as a complete ecosystem is a good example. It provides shelter. It is a habitat for large number of species. The electricity consumption in India, 350 kWh per capita per year, is very less in comparison to other developed countries as we are mainly dependent on firewood which comes from the forests. Nearly 15000 crores of fuel is burnt in India per year, for cooking which comes from forests. Besides firewood it gives us many other products like gum, resins, thorn, timber, medicinal herbs etc. as discussed earlier. So forest is our life line. Whenever, we have a project we have to asses its impact on this lifeline.

What will be the effect of navigation on water course? It shall be the spread of oil, grease, noise and water currents. One has to consider all these negative impacts.

For a good and exhaustive example let us consider the environmental impact assessment of some big projects like water resources project. First of all in 1970 s Aswan Dam constructed on river Nile had a problem of its impact on environment. The problem may be of seismicity. Earthquakes below 2.5 intensity on Richter’s scale goes unnoticed whereas those more than 4 are felt with discomfort. Kariba and Koina are the  places  where  first  of  all  it  was  assumed that  earthquakes  took  place  due  to construction of dams. But the actual effect is not quantified yet, though a certain correlation is there.

Changed water balance is, of course, to be studied. When we have irrigation projects the hydrology of the area changes. In the command area per square meter availability of water is much higher than required so water logging takes place. The consumptive use of water is 4 to 5 mm/day  for plants. 90% of water taken by a tree is evaporated and only 5% is used by the body. As lesser water is consumed by plants in a command area so high water vapours will be formed that will increase the humidity. The rise in humidity shall have microclimatic changes like change in temperature. Water logging takes place as a result of supplying more water than required. Flood pattern downstream are changed. Drought characteristics are changed. The filling done in construction of canal embankments blocks the natural water ways. In command area type of crop is changed.  Wheat  is  replaced  by  cotton,  sugarcane  etc.

Soil is endemic saline if it contains salt. When no water was there to leach salts, it remained at bottom. When the level of water comes up the salt comes up and when it gets evaporated the salt remains there only and the soil becomes saline. So many other impacts are there and as such, before the actual quantification one has to finalize the areas on which the impact assessment is to be done.

METHODOLOGY OF ENVIRONMENTAL IMPACT ASSESSMENT

The following steps are taken in the overall assessment

1. Identification
2. Data  collection
3. Prediction
4. Assessment

Let us discuss them one by one with some specific examples.

• Identification of Impact Areas

Depending upon the project under study there are so many areas over which the impact assessment may be made. Some of them are common and can be usually applied on all  projects.

• Water Resource Project

Let us consider them for a water resource project. It has a dam, reservoir, canal and the distribution system etc. The dams have a large impact on the environment as sometimes they are very large. In Egypt, the Ashwan High Dam is seventeen times heavier than the great pyramid of Cheops. In Ghana the Volta Dam impounds a reservoir of the size of the Lebanon. Construction of dam inundates large areas of the fertile land.It is difficult to assess this loss. It is not only in terms of just the market value of the crops lost but also the top fertile layer of soil known as the humus. Nature takes hundreds of years to make one inch of humus. Vast area of land has been submerged under the water resources projects. For example 84800 hectare were lost in the Volta Dam. 510000 hectare was lost in the Kariba Dam and 400000 hectare submerged by the water of Lake Nasser. The Narmada Valley Development Project in India with 30 big  and  3000  total  dams  will  drown  350000  hectare  land.

Let us study the impact of the water resource project one by one in different areas

• Population: When a dam is constructed to store water a large reservoir is created on its upstream. This reservoir may be sometimes spread in kilometers. So the land or forest or habitation submerged under this water is lost for ever.  A  tree  may  cost  some  thousands  of  rupees  for  an  engineer  but  its environmental value is in lakhs. As explained earlier if the services rendered by a fully grown tree for its whole life are quantified in terms of money it is about 5 lakhs. The environmentalists have warned that in Narmada Sagar command area the cost of submerged forest is Rs. 30000 crores.   They have also  estimated  that  by  the  construction  of  Narmada  Sagar  Dam  (second largest of the Narmada Valley Project) 30000 families ( 2 lakh persons) shall be displaced. The same has happened for Tehri Dam. The occupants of town Harsood did not vacate the town until it was really submerged. Actually this  is  the  biggest  problem.  Nobody  wants  to  leave  his  place.

The  sameexamples are there for other countries also. By the construction of Three Gorges dam in China 1.4 million persons were displaced. Ghana’s Volta dam saw the evacuation of some 78000 people. The Pa Mong project in Vietnam uprooted 4,50,000 people. The Narbada valley development project of India (having        many small and large dams) shall also displace about 1 million people. As a general estimate for every 100 benefited persons about 6 are at loss (to be rehabilitated). The displaced persons of Pong dam could not be  rehabilitated  for  decades.  Ultimately  they  were  shifted  to  Rajasthan where they faced many problems of harsh climate and different culture. The problems of resettlement are as follows:-

1. As compensation to the acquired land the government pays in terms of the last registry rate that is always lesser than the market value.
2. Generally those who obey the orders first are at loss as they get the initial compensation and are away from the scene. The more adamant ones sometimes get  more  compensation.
3. The houses, trees, Dhanies (hamlets), wells etc. are assessed by the government officers on there set rules of Basic Schedule of Rates that is always less than the actual. In the B.S.R the depreciated value of house in 100 years becomes nil whereas in practice people live in houses that are older than 100 years. So it becomes difficult to decide about the compensation of such old houses. Same is the case of trees. The tree is assessed on the basis of its girth and the assessed cost is something about 3 to 5 thousand depending upon the wood. But the real cost (environmental cost) is very high.
4. Land to land conversion is not possible because the government lands of the same type (fertile) are not available. When money is given in compensation to land it is generally not utilized in purchasing the land and spent in some other unuseful expenditure like marriages etc. Many times the sons get it divided  and  the  hard  earned  asset  of  the  farmer  is  snatched  from  him leading him to be bankrupt in some cases.
5. The shifting charges are meager say 1500 Rs. Per family. The families in the villages are combined families and when they lose their land and get money, the joint families split up and as such the shifting charges for such increased families  become  totally  insufficient.
6. The main problem in resettlement is the sentiments of people. Everything cannot be compensated in terms of money. The feelings attached to the houses, fields cannot be quantified in terms of money. The feeling of uprootment and to settle in new conditions is intolerable especially for elderly  persons.
7. Sometimes some over wise persons go on such sites and encroach some land to  get  fake  compensation

Considering all these problems the engineers, planners and managers must take the people in confidence and realize their problem in totality. The policy should be framed to rehabilitate (Punarvas) them not to only resettle (punarsthapan) them. The difference in the two is the real key to success. In the rehabilitation the new village is constructed as the old was. Considering their local demands of panchayat- ghar, open wells, community places, schools, dispensary, meeting places etc. and the construction should be suiting to their local requirements. Generally government makes same type, stereo type, row houses for them that are never accepted to them. Making a village similar or improved to the old one with people’s participation and their will is the real rehabilitation. The policies and awards should be site specific and made on ground realities.

Any single policy made indigenously or borrowed from foreign countries cannot be successful in the vivid conditions of our country. For example the problem of land acquisition for the construction of Rjeev Gandhi lift water supply canal for Jodhpur was solved by raising the peoples sentiments for a noble cause of supplying drinking water to human beings and cattle’s of the desert district. The feeling of sacrifice for others generally works in such matters.

• Meteorology: As a large reservoir is formed or a canal passes through a region local microclimatic changes take place. Presence of water vapour is most important. The maximum temperature comes down and minimum tempera- ture increases. Number of hot days will reduce. Stretch of high temperature will also reduce. Nights will be warmer. As the humidity increases there may be local showers. Permanent presence of clouds will remain. In Aswan dam (Egypt) 5000 square kilometer are of reservoir is there so permanent clouds are formed giving daily some showers.

• Water resources: As it is a water resource project obviously the water resource on upstream side shall increase so there is a positive impact on upstream side. The down stream of the river shall face water shortage. But the overall impact is positive as a dam prevents the fresh sweet surface water to be ultimately mixed with the saline water of the sea. So the net balance is positive. The dam also prevents the flow of useful silt to the sea and thus saves a very large amount of money in terms of humus and useful silt.

• Floods  and  droughts: The  main  purpose  of  constructing  a  dam  is  safety against floods. A dam stores the rainwater at the time of storm causing floods and relieves it throughout the year as per the demand. Particularly in summers when there is no rainwater and the river is also dry, irrigation can be done through the canal system. So the impact is positive on both floods and droughts  and  if  quantification  is  done,  maximum  marks  in  favour  of  the project shall be given on this basis.

• Water quality: In the reservoir the water stands still so due to sedimentation the silt and other settleable impurities settle down. Water becomes clear as the turbidity reduces so it is a positive impact on water quality from aesthetical point of view or drinking water point of view. From irrigation point it is a negative point as the silt is always useful for crops. The second quality parameter is dissolved oxygen. Water takes D.O. from the air and it gets mixed in it depending upon the deficit and the temperature etc. Water has a specific capacity to contain the D.O. at a temperature. For example it can have 9.17 mg/litre  of dissolved oxygen at 20° C. It reduces as the temperature increases.
• Minimum 4 mg/l  (ppm) D.O. is required for the existence of aquatic life. When the sewage or the organic matter in any form gets mixed in the river water the bacteria consumes this D.O. for its decomposition. As the D.O. reduces water tries to recuperate it from the atmospheric air. As soon as the upper layer of water gets saturated the further penetration of oxygen reduces. When the river is flowing with turbulence the upper layers come down and the lower layers come up to absorb more and more oxygen and thus the whole water is having good amount of D.O. But when the water is stored in a reservoir this  phenomenon  stops  and  only  the  upper  layer  is  exposed  so  the  D.O. reduces and thus it is a negative impact on the quality of water.

Due to the increased depth in the reservoir the penetration of sunlight reduces and the formation of oxygen by photosynthesis also reduces. This deteriorates the quality of water and thus it is also a negative impact.

In the reservoirs generally the sewage of the nearby cities is discharged which is full of nutrient (nitrogen, phosphorus etc.) Due to increased nutrients heavy growth of plankton takes place. This can be phytoplankton or zooplankton (wandering). Blue green algae can grow even in the absence of nutrients as it takes nitrogen from the atmosphere. The velocity of water is zero and nutrients are there so the aquatic plants like water hyacinth flourish like anything. These plants cover the whole lake or the reservoir in very less time. This further reduces the penetration of sunrays and thus causes anaerobic conditions. This is known as eutrophication and is a negative impact on water quality.

• Water  logging  and  salinity: Generally,  the  reservoirs  are  not  situated  on completely impervious base. The canals also have seepage inspite of all efforts. This water goes down and if the soil is impervious it comes back on the surface and stands still there only. This permanent storage of water in the root zone of plants is known as water logging. This does not allow the growth of any plant as air is a must in the root zone of the plants. So this is a negative impact. In the initial reaches of Indira Gandhi Main Canal (near Hanumangarh) and also near R.D 1120. water logging has taken place. This has reduced the cost of previously costly land to almost zero. The seepage water dissolves the salts of the soil and they come up with the water. The water evaporates leaving the salts there only which makes the soil saline. The saline soil is unfit for irrigation and thus this is a negative impact.

• Water supply and sanitation: The water resource project certainly increases the water supply on the upstream side. This water is used mainly for irrigation and also for drinking water supply. Though the quantity of water used for drinking water supply is very less in comparison to the irrigation water sometimes it may be more important for example in desert areas. In any case the water supply increases and people feel comfortable. At least animal husbandry (cattle business) can support human life in such desert areas with less scope of agriculture. The increased water supply increases the sanitation also. When there is enough water for cleaning, bathing and removing the fecal matter with water (water carriage system) then good sanitation can be maintained. So it is a positive impact. However, the water carriage system (flush system) requires a very large amount of water 99% to carry very small amount of night soil (fecal matter) (1%) and as such a wastage of good quality potable water. Any way the diseases due to poor sanitation are reduced.

• Drainage: As  the  water  supply  to  the  towns  increases  the  waste  water (sewage) comes on the streets. With less water and less sewage it could be managed in kitchen gardens and the open drains. As the volume of water increases many times and the sewage conveyance and treatment becomes necessary before its disposal. The sewerage system is very costly, even costlier than the water supply system. In India we still do not have sewerage system in most of the cities.

• Soil: The soil is affected mainly by two ways

• Fertility: With the plenty of irrigation water farmers take two to three crops in a year. Due to over utilization of  land the fertility of soil reduces. Though we add fertilizers, artificial or organic, but micro-nutrients are not there. So the overall fertility reduces and the biology of soil changes.

• Soil erosion: Increased farming operations, like tilling, loosens the soil which in turn gets easily eroded by flowing water or the wind storms. The top soil known as humus is washed away in few years where as it has taken thousand of years in the production. Roads are made and the excess cutting may lead to slope failure. Increased pore water pressure leads to land slides. The right bank of river on which Vaiont dam was there in Italy ( a double arch dam) collapsed and fell in the river in 1962.

• Land use: The land use pattern changes drastically. The plenty of irrigation water increases farming and cultivation. The grasslands and land for grazing of cattle also comes under cultivation (agriculture). The animals find it difficult to live and their encroachment to the fields give rise to fights and legal cases. Industries related to agriculture and others come up. Roads, godowns, construction camps, housing projects are developed leading to urbanization.

• Agrochemicals: For the increased agriculture more and more agrochemicals like fertilizers (Urea. D.A.P.), pesticides, insecticides, etc. are used. Generally they are used even more than the required quantity. D.D.T. is banned in the advanced countries but still used in our country. These chemicals enter into our food chain and many times their concentration in mother’s milk is much more than permissible. Recently it was found that the concentration of pesticides in the cold drinks was much more than permissible. Sometimes the farmers are so wise that they don’t use chemical fertilizers and pesticides on the product they use for their own consumption. Even such products are available in market that have been grown on natural organic manure or vermicompost (made by special earthworms, naturally) and without the use of pesticides, but at a higher rate.

• Ecology: As the water resource increases more and more land comes under irrigation and the farmers grow only those crops that pay them the best. So the species diversity gets reduced. Production is more under favourable conditions so wild and tough goes away. All the ill effects of reduction in biodiversity are there.

• Forest: The area of forest gets reduced due to submergence. About 2% of the forest area has been reduced due to submergence of water resources projects. The type of forest changes from close forest (> 40% is covered by self generating set of plants), to open forest (10-40% covered by plants) or to scrubland (< 10% ). Tribes live in harmony with forest and wild life but when  they  are  displaced  they  cause  deforestation.

• Wildlife: Forest is the habitat for wildlife. Presence of human beings make disturbance even if the forest is not cut down. As the canals, roads etc. are constructed the animals feel segmentation of their habitat. The interference, quality change (running water becomes stagnant) and segmentation leads to direct reduction in their reproduction rate. Particularly for the lion group the reproduction gets substantially reduced in lieu of the reduction in area under their command. The aquatic life is also affected. Estuarine fish moves for salinity from land to sea for breeding. If there is some obstruction (dam) their movement is stopped and thus reduces their breeding. Even if we provide fish ladders only 15% can use it.

• Fisheries: The  species  diversity  of  the  fisheries  is  reduced  because  of  the development of man made controlled fisheries. Fish are very sensitive to dissolved oxygen, temperature and salinity. They have some breeding habits and their herding (shelter requirement ) is peculiar. For example the estuarine fish requires salinity. The assured water increases the habitat and their production though species may be limited. Tilapia, catla catla and corps are generally grown. The production may be as high as 20000 kg/hectare/year under controlled conditions, but may come to about zero if the conditions are unfavourable as species diversity is not there.

• Seismicity: It is said qualitatively that the construction of dams increases the chances of earthquakes (seismicity), though quantitatively it could not be assessed. Actually it is the fear due to the accumulation of huge quantity of water in the reservoir that can induce earthquake. But if we compare it with the large quantity of total water on the earth, it proves to be futile. Two third of the earth is covered by water and the fresh water flowing in the rivers is a very small fraction of the total water. If we restrict (store) a small portion of this little water, it is negligible in comparison to the sea water. So it can not disturb the balance, causing the earth quake. However the seepage water from the reservoir may disturb the tectonic movement of the plates if it reaches to that level. So the dam should be constructed at a safer place and the design should include the possible earthquake forces.

• Air quality: Fortunately in water resources project followed by the hydroelec- tricity generation plant there is no emission of gases or the particulate matter. Only some dust problem may be there at the time of construction particularly if the dam is an earthen dam. So there is no negative impact.

• Noise: Similarly there is no noise problem. Only the turbines for electricity generation may produce some noise that can be controlled and restricted in the pump house itself.

• Historical monuments: Some historical monuments may be submerged in the reservoir. Kadana, Galiakot, Nagarjun temple are the examples. Manibeli temple has submerged in Sardar Sarovar project. Sometimes, if the monument is very important it has to be removed in pieces and rebuilt, or it has to be shifted as such with a great expense. Sometimes, a protection wall is constructed all around it to prevent the submergence under water. So the site should be selected in such a way that no such historical monument gets submerged otherwise it shall be a negative impact.

• Tourism: Tourism  shall  be  promoted.  The  plenty  of  water  promotes  the gardens, boating, adventure games, fun making, fountains and many other recreation facilities. Tourists are attracted to these things and money flows alongwith the tourists to the town. The famous Vrindavan Gardens in Mysore are  constructed  on  Krishnarajsagar  Dam.  So  it  is  a  positive  impact  in  one sense. The other point says that alongwith the tourists foreign culture also invades the local culture. This cultural invasion is a negative impact. AIDS is most prominent in Jaisalmer out of the whole Rajasthan because of the foreign tourists attracted to the deserts of that area. So it is a combined effect and the impact has to be studied carefully considering both the points.

• Health: The improved water supply improves the sanitation and the diseases like diarrhea are reduced as treated water is available in plenty. But as the fecal matter is mixed with the fresh bodies of water (rivers, ponds) as sewage so  water  is  a  vehicle  for the  bacteria  and  viruses  of  diseases  like  cholera, typhoid, hepatitis (Jaundice), gastroentitis etc. These water borne diseases can be controlled only with the proper treatment of drinking water i.e. the dis- infection.  Some  diseases  like  Schistomiasis  and  Guinea  Worm  disease  take place when the schist enters through the foot of a person entering in the water.

• As the water is used in plenty for irrigation and other works many vectors like mosquito are born in abundance and they spread the vector borne diseases like malaria, dengue, brain fever etc. This has a great negative impact. In the command area of the Indira Gandhi Main Canal Project in Western Rajasthan thousand of people die from these vector born diseases every year. However, this mortality will reduce as the population becomes trained against this as in U.P, Punjab, and other states where irrigation is there since a long time.

• Socioeconomic: This includes all the impact on the social structure of the affected community. The main advantage of the water resource project shall be the availability of drinking water. When there is no such project, people had to fetch water from distant sources. In western Rajasthan women fetch water on their head from miles away. The male members waste their whole day in cartage of water with carts from a distant pond. The amount of water so carried was so precious and scarce that was used only for drinking, cooking and the sanitary condition was very poor. As the water resource projects comes, into existence this whole effort, time, energy and money is saved. This has its direct benefits as well as many indirect benefits. The women have time to take care of their health and education and small earnings. They can take care of their children in a better way. Men can go out and earn better as they are free from the burden of water carriage.
• Besides this the irrigation water changes the whole scenario. Firm, assured substantial,  cash  crops  make  them  prosperous.  Every  essential  facility  like road, electricity, telephone, vehicles, medical help, communication etc. is made available to them. Good comfortable houses are built in villages or the farms/fields  there itself. This reduces the migration of rural population to the cities and develops a self reliance in them. Agro based and other industries come up in no time. The growth of self dependant villages is beneficial to the whole  country.

The other side of the coin is the increase of crime rate. The prosperity breaks up the very sense of the combined village community. The pollution and other evils of urbanization  are  there.

The overall impact is positive as some bad effects are always associated with any development. With cautious planning and a good vision they can be overcome.

Hydroelectricity  Project

The other project may be a hydroelectricity project which is an extension of the water resource project. The plants are of two types, one is ‘Peak Load Plant’ and other is

‘Joined with the Grid’. In isolated distant peak load plants whenever the necessity comes a unit is switched on and it starts suddenly. A huge quantity of water is suddenly released that may prove fatal for aquatic life as well as for human beings. The solution to this is in having an equalization tank.

Screens or trash racks placed before turbines prevent larger fish say >  5 cm. but smaller fish caught by the vortex motion go inside and are killed in the blades of turbine. But there is no thermal pollution etc. so it is comparatively cleanest technology of electricity  generation.

Navigation Project

The water resources project can also be used as a navigation project with a huge canal for transportation of ships, boats or directly the wood logs etc. The following are the impacts:

•    Grease and oil floats on the surface of water that prevents the penetration of sunlight.

•    The photosynthesis is badly affected.

•    Surface water waves run along the bank and thus the banks are eroded.

•    Stagnation  takes  place  at  jetties.

•    Leaching of chemicals from nearby godowns takes place.

•    If continued with dams, Lock Gates cause discontinuity in flow pattern.

Tidal Hydroelectricity Project

Tidal hydro plants are pilot plants in the gulf of Combay. In India we have only 4 to 5 metre high tides. In this type of power plant we make a bund across the definable banks of a river where it meets the sea. The water is lifted up and down at the time of high tide and low tide. This movement is converted into electricity by the turbines. Low head turbines have been developed that can work on varying heads also. The impact areas are as follows:

•    Aquatic  organisms  which  thrive  on  tidal  cycle  are  adversely  affected. When  they  pass  through  turbines  they  die  due  to  high  speed  and restricted  movement.

Geothermal energy

In this type the heat inside the deep earth is used for making steam and running the turbine. Though very small percentage of the total but at some places like Sanfransisco about 25% electricity production is by Geo thermal energy. The impacts are as follows:

•    Thermal pollution is there.

•    Hydrogen sulphide and other mineral obnoxious gases come out.

Solar energy

Solar energy conversion into electricity by photovoltaic means and thermal means both are very good options.

The impacts are as follows:

•    The  pollution  caused  in  the  manufacturing  of  solar  photovoltaic  panels  is tremendous.

•    The solar thermal chimney based plants require a very high chimney that may be dangerous from strategic point of view

Thermal power plants

These are the most common ones. Fossil fuels like coal or oil is burnt and steam is formed and the electricity is generated in these plants. The impacts are as follows:

•    The main adverse impact is the air pollution. Lot of CO and CO2   are gen- erated. CO2   is the main culprit of global warming.

•    Oxides of nitrogen and sulphur are liberated that cause acid rain and many diseases in human beings and even loss to the building property etc.

•    In the mining of coal unsightly conditions develop. The abandoned mines collect water which produces reduction in ground water and other problems. Loss of top good soil takes place due to mining.

•    The coal particles and the suspended particulate matter spread in the air up to many kilometers and the nearby residents develop many respiratory and other diseases.

•    The  fly  ash  and  bottom  ash  generated  poses  a  great  problem  of  disposal.

Mounds of ash are created. However, these days the cement manufacturing

and brick manufacturing industries are using the fly ash in abundance.

•    The hot water discharged into the reservoir pool causes thermal pollution and proves fatal to aquatic life.

•    The releasing of steam produces noise pollution.