Guwahati city is one of the most ecologically endowed urban areas of India. The city boasts of many hills with lush green cover which are inhabited by different forms of wildlife. The city also has two notified wildlife sanctuaries apart from eight other forests reserves. Further, the city also takes pride in the existence of the Deepor Beel – the lone RAMSAR site of Assam. Guwahati is also one of those metropolis of the country where we find lots of natural streams and river channels traversing the entire topography. The Bharalu river, Mora-Bharalu, Basistha and Bahini river, all of them together forms an intricate hydrological network within the landscape of Guwahati city. However, even though this rich ecology seems to be an indicator of being sustainable and eco-friendly, yet there are numerous other reasons because of which people no longer consider this city as habitable. One of such numerous reasons is the rapid degradation of the natural waterbodies including the streams and rivers.
In fact, the Bharalu river, which is one of the south bank tributaries of the mighty Brahmaputra river, is listed as one the most polluted rivers of the country. Since the last four decades the Bharalu river has faced severe degradation owing to severe pollution, alteration of hydraulics, loss of ecological habitat, etc. Rapid and unplanned urbanization across all parts of Guwahati city is at the most the root cause of all problems of Bharalu river. The negative changes that occur to such streams and rivers that drains urban land are collectively known as “urban river syndrome”. Impacts of urbanization on a river system can be multifold. The major categories of elements that can be impacted upon are the catchment processes, flow regime, habitat, water quality, sediment chemistry, aquatic and riparian biodiversity. Some very predominant signs of urbanization and its impact on streams and rivers include the increase in frequency of overland flow, pollution load, magnitude of high flow, rise and fall of storm hydrograph, increased impacts of nutrients (Nitrogen, Phosphorous), toxicants and also the increase in invasive species. On the other hand, decreasing trends are observed in case of infiltration, lag time to peak flow, nutrient uptake and also there is a significant decrease in abundance and diversity of fish, invertebrates and macrophytes. Most of these symptoms are observed in the case of Basistha-Bahini-Bharalu stream network of Guwahati city. The population of Guwahati city is estimated at around 7 lakhs and the population density is 2695.43 per sq.km. as per census 2011, which is very high. So it is very obvious that such a high population will exert tremendous pressure on the natural resources for meeting the needs of infrastructural development as well as for fulfilling basic human needs. The human pressure is evident from the fading green cover from the hills and the conversion of once vibrant natural streams, the Bharalu and Bahini, into putrefying sewage canals. A growing concept among water professionals across the world is that of “River restoration”, which includes all actions aimed at improving the river health. River restoration managers aims not only to improve the health of a degraded river but also to improve the overall ecosystem function and related ecosystem services. River restoration becomes necessary in case of rivers where the system have degraded to a point where they can no longer deliver the expected ecosystem services. However, it is often recognized that urban rivers which are highly degraded and modified, restoring such waterbodies to a pre-development state or to a state wholly resembling a natural system is highly unlikely. At least, this is not hundred percent achievable when considerations are to be made with regards to maintaining the societal function expected from the river system. Yet, river restoration benefits cannot be undermined because such restoration in urbanized settings has helped bring about wider socio-economic benefits as evident in many cases worldwide. This is why a robust restoration and rejuvenation plan must be developed based on sound scientific inputs and thereafter implemented for the entire stream network of Basistha-Bahini-Bharalu of Guwahati city. While considering restoration of our city rivers and streams, there are 3 key challenges before us:
It is a well-known fact that at different times in the last five decades, all these departments and agencies have been engaged or entrusted with some works related to the city rivers or other waterbodies. Lots of money have also been utilised for various kinds of projects, particularly for dredging and cleaning of the Bharalu, Mora Bharalu and Bahini river by the GMDA. But, till date there has been no permanent solution to the problems associated with these rivers. Rather, the problem has been attenuated by many times due to lackadaisical efforts of government agencies and also due to implementation of faulty projects. Therefore, it is important to realise the fact that an integrated strategic approach is the due need of the hour for restoring of Basistha-Bahini-Bharalu river network. To address the challenges mentioned above, a strategic approach shall be required for a complex network of streams like that of Guwahati city. It would require-
Finally, all restoration activities should be manned and executed in such a way that it ensures sustainability of the restoration outcomes. Restoring Basistha-Bahini-Bharalu river network and other smaller streams too, must involve all stakeholders including local communities. Inter-agency collaboration and community participation shall be the key to the success of restoration projects.
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Since time immemorial man has tried to bring nature under his control. The urge to control nature emerges from two basic thoughts - (a) that nature is capable of destruction and creation and so it needs containment (b) and that nature being plenty of resources can be exploited for development. Construction of dams throughout the world has its roots in such views of nature. Dams are built to exploit the hydro-power to generate electricity required for the growth of a nation. At present construction of mega dams faces lot of opposition from different quarters of the societies. Debate between the proponents and opponents of dams pivots around the perceptions of environmental, social and economic impacts and benefits of mega dams. Mega dams not only causes severe ecological destruction but also causes serious and long term anthropocentric problems. Some of the common issues are listed below:
Such degradation of human life only forces us to think that the one section of the society enjoys the gains from hydro-power projects while others share the costs and pains of this development. Cultural rights are as important as any other human rights. Cultural rights are an expression and requirement of human dignity. As such their recognition and protection are vital for the sustenance of any community. Here lies the hidden cost which always remains unaccounted for in the planning stage of any hydro-power project development. It is the moral responsibility and constitutional duty of the Government to safeguard its citizens from any injustice meted out by such development projects and take up initiatives to preserve the cultural rights and identity of the people. References: 1. The Hidden Cost of Hydroelectricity Dams: Cultural Survival, 2010 2. Balancing Pains and Gains . A Perspective Paper on Gender and Large Dams, WCD Thematic Review,2000 3. Heritage at Risk 2001-2002: Dams and Cultural Heritage When we talk about the rivers in Assam, we usually talk about the geomorphological and the hydrological characteristics of the Brahmaputra and Barak river systems. We tend to discuss more about the ill effects of the recurring flood and erosion caused by the rivers. We blame the rivers for the economic devastation they cause to our state annually and also for the loss of lives and livelihood of the people. But, we rarely discuss how we human beings are silently killing the rivers by polluting them. River pollution is an insidious problem and we never discuss it or take any curative action until it manifests into a major civic problem. River pollution at large draws very little attention of the society. In India it is only because of a series of reports by the CPCB and subsequent court directives, that the Govt. and civil society is taking up the issue of river pollution at fore. Same is the situation in Assam.
As per the CPCB report of 2018, there are 44 pollution river stretches across Assam falling in the priority classes from I to V; river and water bodies falling in priority class I are the most highly polluted warranting immediate action. Assam stands at the second position in the country after Maharashtra for having the second highest numbers of polluted river stretches. It is interesting to note that although Assam is comparatively a less developed state in terms of industrial infrastructure when compared to other states like Gujarat, UP, Haryana etc., yet the rivers of Assam are highly polluted. The level of pollution in river stretches has been determined on the basis of some key parameter like the Biological Oxygen Demand (BOD) among others. Let us go into depth of the technical details of the CPCB report. Firstly, out of the 44 ‘‘Polluted river stretches’’, there are 39 actual river stretches and the rest 5 are wetlands. Again among the rivers, there are two stretches that are within the main channel of Brahmaputra and the Barak river. Rest of the river stretches fall within various tributaries of these two rivers. Thus, different stretches of river in both Brahmaputra and Barak valley are polluted leading to unacceptable level of BOD values. According to the CPCB report, the river stretch in Brahmaputra (from Kherghat to Dhubri) had BOD levels upto 6.4 mg/L and in the Barak (the river stretch from Panehgra to Silchar), the BOD values ranged from 3.5-4.2 mg/L. According to CPCB criterion, the particular stretch of Brahmaputra fell in the Priority class III and the stretch within Barak river was categorized as Priority Class V. Now among all the tributaries of Brahmaputra-Barak river systems, the CPCB has identified the Bharalu river to be the highest polluted with maximum BOD value reaching upto 52 mg/L. This resulted in the Bharalu river being categorized as a Priority Class I waterbody. Similarly, in the same report, CPCB has identified the Borsola & Silsako wetlands of Guwahati city as Priority Class I waterbodies owing to very high BOD values reaching upto 30 mg/L. Also, the Sorusola Beel and Deepor Beel (both wetlands) have been placed in priority class II and priority class III respectively due to high BOD values. Now, the Bharalu, river, Silsako, Borsola, Sorusola and the Deepor Beel are all located in the city of Guwahati. Rapid urbanization and unsustainable way of city management is the main culprit behind the pollution of these once pristine freshwater ecosystems. One must also take note of the fact that Deepor Beel is a protected area - a wildlife sanctuary and the lone Ramsar Site of Assam. Yet, owing to unsustainable practices of the citizens and apathy of the Government agencies, the BOD levels were at beyond acceptable limits with a mean value of 10.6 mg/L. Now the question arises as to what has contributed to so much of high levels of BOD in rivers and other water bodies of Assam. The main reason behind such high BOD levels is nothing else but pollution due to high input of organic matter load. The readers must be aware of the fact that the state of Assam does neither have a public sewerage system, nor any installed sewage treatment plant (STP). Therefore, all the domestic sewage alongwith other industrial effluents and other wastewater are directly fed to the storm water drainage system which ultimately carries the mixture directly to the rivers and waterbodies. Let me explain the situation with the case of Bharalu river. Basically, Guwahati city has a natural drainage system- a network of natural streams - which I preferably call as the Bahini-Bharalu-Basistha river system or network. These individual streams flow through an entirely densely populated residential, industrial and commercial areas of the city. All these 3 rivers are highly impacted in terms of pollution. In terms of geomorphology, Bahini constitutes the upstream stretch of the Bharalu river. During the 70’s, the river water was clean and people used to catch fish and also used the water for religious rituals. However, the water quantity started to deteriorate after 1983-85. We can attribute this sudden change to the diversion of a part of Bahini to Basistha by excavating a channel and setting up a sluice gate. This was done in the year 1983 by the erstwhile Flood Control Department. The project significantly altered the natural hydrological condition of the downstream of Bahini river, i.e. - the Bharalu river. Simultaneously, there was tremendous population growth and unregulated settlement within the city since the govt. had shifted its capital from Shillong to Dispur in Guwahati. In the absence of a dedicated sewerage system and due to weak or non-existent environmental regulations during that period, the Bharalu river started receiving untreated wastewater, sewage and dumping of solid wastes which still continues unabated. In the absence of environmental flow of the river, Bharalu turned into a sewage canal. In my own research it was observed that there is total absence of fish fauna and presence of only pollutant tolerant species in the pollution impacted stretches of the drainage network. Water quality analysis shows that Dissolved Oxygen (DO) ranged from 0.0 - 5.40 mg/l with a mean of 3.71 mg/l. Thus, there are many stretches within the B-B-B river network which are technically ‘‘hypoxic’’ (absence of dissolved oxygen in water). According to Govt. reports, BOD values were found to be as high as 54 mg/l. BOD was above the permissible limit and it significantly deteriorated as we proceed downstream. Another, important water quality parameter is the ‘P’ (Phosphorous) - determined as Phosphate (PO43-) which was found to be maximum of 11.37 mg/l, which in above the permissible limit of 5.0 mg/l. The reason behind such pollution is the direct entry of about 70 MLD (million litres per day) of sewage which is further projected to increase to 280 MLD by 2025 and all of these are carried down by around 330 drains. Further, as per CPCB and other Govt. agency reports, the bacteriological contamination was very high as indicated by the water quality parameter - Fecal Coliform count. Fecal coliform count in the river water was found to be 3000 MPN/1000 ml which is way above the permissible limit. Apart from the above categories or types of pollution, rivers in Assam also faces same other serious forms of pollution like oil spillage, heavy metal contamination etc. There have been increasing numbers of instances of oil spills in the past 10-15 years. More than 100 incidents ranging from small to moderate to major oil spills have been reported in the state in past 10 years. As far as heavy metal contamination of Brahmaputra river in concerned, a recent study by researchers from Cotton University have found that the concentrations of Nickel, Chromium, Mercury and Cadmium were very high in the river water, the concentration being highest in the stretch along Guwahati city. Another serious pollution of river water in Assam is due to the occurrences of pesticides and polycyclic aromatic hydrocarbons (PAH). In a research conducted in 2011, the mean concentration of DDT was 5402 mg/L and 6121 mg/L in Dibrugarh and Nagaon surface water sampler. According, to the study 93% of the samples for DDT exceeded the WHO permissible limits for drinking water. Thus, from the above discussion we can say that the main sources of river pollution in Assam can be categorized as -
Controlling river pollution is definitely not an easy task. It involves not only whole hearted efforts of the govt. but also active cooperation from the public in general. A broad strategic plan would be required to mitigate the pollution of Brahmaputra and Barak river system and the connected wetlands. Until a long term plan in derived, some actions can definitely be taken up by the Govt. as short term measures. These may be both structural & non-structural. Structural measures should be taken up keeping in view the longer term plans, so that there doesn’t occur any duplicity of work and public fund is not wasted. Keeping in view, the condition of the rivers of Assam, the following measures should be taken up urgently for mitigating the pollution problem:
Encyclopedia Britannica defines Environmental Science as an “interdisciplinary academic field that draws on ecology, geology, meteorology, biology, chemistry, engineering, and physics to study environmental problems and human impacts on the environment. Environmental science is a quantitative discipline with both applied and theoretical aspects and has been influential in informing the policies of governments around the world.”
Another very convincing definition of the subject is given by SOAS, University of London whereby its states that Environmental Science “refers to a type of scientific discipline in its own right, one in which a broad range of insights from other branches of science are brought together (synthesized) to inform the understanding and management of contemporary environmental issues.” Like the above two, there are many other definitions which describes the academic field of environmental science; but most fall short of defining the true characteristics of the subject and in totality. Again, there are some definitions where the terms 'Environmental Science' and 'Environmental Studies' are used interchangeably which is not correct. Also, in India there are a number of textbooks on environment wherein authors have projected Environmental Science as a 'multidisciplinary' subject, which is conceptually inappropriate. Therefore, this piece of article is aimed at resolving the issues and providing a plausible definition that could be accepted by the peers within the field. Environmental Science, as an academic discipline, is holistic in nature. Generally, science subjects are atomistic and are analytical in their approach and mostly analyzing only selected variables to explain a phenomenon or process. However, in nature, environmental processes are very dynamic and involve large number of variables. To explain such processes in totality and accurately, all the involving variables needs to be taken into account while carrying out the scientific investigations. In fact, the study of environmental change is considered central to environmental science. Therefore, it would not be wrong to state that the central approach in environmental science is antithesis to the atomistic approach of other branches of natural science. Environmental investigations and other activities within the domain are descriptive as well as analytical. Environmental scientists use both descriptive as well as analytical methods to study the constantly changing environment at both spatial and temporal scales. Environmental science involves concern for situations that have real consequences for the society and therefore environmental scientists are largely regarded as being subjective in their evaluations. However, this cannot be generalized or held true because conclusions and recommendations concerning an environmental issue are usually based on actual scientific experiments and investigations. Professionals in the field of environmental science do seek alternative solutions to environmental problems and developing the basis for choice between alternatives. Thus, the subject will always contain ethical, moral, socio-economic and political dimensions to a certain extent. Many see environmental science as an instrument that can be used to support and promote environmental stewardship, conservation and protection. On the other hand, many argue that environmental science should be free of subjective influences. Practitioners should not advocate a particular viewpoint and instead singularly focus on “collection, communication of robust verifiable data”. Such contradictions are usually observed in debates concerning development of the built environment. However, when one talks about scientific ethics, scientist does have moral obligations towards the society. This is also true in case of the environmental scientists. Therefore, environmental scientists and other environmental professionals must always act in a manner that favors environmental protection and sustainable development. In addition, they are expected to put forward professional judgments based only on scientific evidences. Another very critical issue that needs to be addressed is to determine whether environmental science is a multidisciplinary or an interdisciplinary academic field. The subject has evolved over the past six decades and has established itself as an unique academic field and enjoys ever increasing importance; however, the fact remains that it owes its growth to the advances happening in other fields of basic sciences. Since, the larger domain of environmental science has overlaps and intersects with domains of other academic fields, therefore it is usually categorized as either of the following: multidisciplinary or interdisciplinary. The term ‘multidisciplinary’ is applied when perspectives from different disciplines are brought in to illustrate a topic, i.e. the same topic is studied from the viewpoint of more than one disciplines. On the other hand, ‘interdisciplinary’ subjects emphasize on “combining contents, theories, methodologies and perspectives from more than one discipline” (International Bureau of Education, UNESCO). Thus, it is quite clear that Environmental Science is obviously an interdisciplinary subject and not multidisciplinary as projected by many institutes and universities in India. However, there is another term – “Transdisciplinary” which may be applicable to environmental science considering the current state of development of the subject. According to IBE-UNESCO, transdisciplinary approach emphasizes on “dissolving conventional boundaries of disciplines and organizes teaching and learning around construction of meaning in the context of real world problems and themes”. The distinguishing characters among the different types of disciplinarities can be depicted diagrammatically as in Figure 1 of Tytler, Prain & Hobbs (2019) . Therefore, it is quite possible and would be appropriate to term Environmental Science to be a transdisciplinary subject since it is able to “create a unity of intellectual frameworks beyond the disciplinary perspectives” (Jensenius, 2012). Therefore, from the above discussion and based on personal experiences, I would like to present here an alternative and comprehensive definition of the “Environmental Science” as follows: “Environmental Science is a transdisciplinary academic field, whereby environmental components, processes and contemporary environmental issues are studied in a holistic way, applying scientific methods and insights from other branches of natural sciences, so as to be able to assess environmental impacts and provide sustainable solutions for the problems within a singular framework.” The current issue at hand needs more elaborate discussion and on a larger platform. However, the definition presented here is from the perspective of a researcher in the subject and therefore with inputs from other academicians and active professionals in the field shall be helpful in refining it further. Bibliography: Jensenius, A. R. (2012). Disciplinarities: intra, cross, multi, inter, trans. Jensenius, AR, blog posts,[Megtekintve: 2015.03. 05.], University of Oslo, http://www. arj, (2012/03), 12. Tytler, R., Prain, V. & Hobbs (2019). Rethinking Disciplinary Links in Interdisciplinary STEM Learning: a Temporal Model. Res Sci Educ (2019). https://doi.org/10.1007/s11165-019-09872-2 Websites accessed: UNESCO - International Bureau of Education. (2013). Glossary of curriculum terminology. http://www.ibe.unesco.org/en/glossary-curriculum-terminology Encyclopedia Britannica https://www.britannica.com/science/environmental-science Readings, K. Unit One: The Earth System and its Components. SOAS, University of London. https://www.soas.ac.uk/cedep-demos/000_P500_ESM_K3736-Demo/unit1/page_09.htm |
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