Environmental Impact Of Dams

Scientific Essay from the year 2013 in the subject Environmental Sciences, grade: 10.0, Indian Institute of Technology, Delhi, language: English, abstract: According to WWF: • Worldwide the total amount of water stored in dams is 3-6 times more than that contained in rivers. • The wetlands area during the 20th century has decreased by over 50%. • Out of the 10,000 recorded freshwater species more than 20% have either become extinct, threatened or endangered in recent times. These facts are enough to justify the tremendous impact on environment dams are having. Large scale projects like dams are often floated as important and necessary means of economic development. But this development comes at some or the other cost. Cost to the environment, development and society. So what are dams really for? • Water supply for the general public for domestic uses as well as irrigation which is imperative for our agrarian Indian society. • Hydroelectric power generation. India is the 7th largest producer of hydroelectric power with 114 Tetra-watt hours. It produces 3.3% of the world total. • Dams impede the turbulent and sudden flow of water to prevent floods. Well that is what they are for and granted many of them achieve the above given purposes but they are subject to widespread criticism and debate. Several vehement national and international movements have brought into light the severe problems associated with them. Dams have been criticized for disturbing natural water flows, affecting deposits of nutrients as well as lifecycles of species that depend on freshwater habitat. Reductions in water quantities can increase salinity and make the water unusable for drinking and irrigation. The transport of sediments that are crucial for natural cycles is also affected. This may cause flood risks, lower groundwater tables and in turn affect entire ecosystems. With that said we must point out that dams do not always have a negative impact on habitats. E.g. once reservoirs become established they can become sites where birds can thrive. There are cases where dam projects have taken up significant compensation for the environmental damage they had caused during their initial phases, but these cases are few and far between. In this report, we take up the issue of impact of dams from three different perspectives which we believe are best suited for such a topic: - Economics, Population and Risks and Hazards. We first present them individually and give a brief analysis of each perspective then we present a comprehensive and thorough conclusion at the end.

This open access book surveys the frontier of scientific river research and provides examples to guide management towards a sustainable future of riverine ecosystems. Principal structures and functions of the biogeosphere of rivers are explained; key threats are identified, and effective solutions for restoration and mitigation are provided. Rivers are among the most threatened ecosystems of the world. They increasingly suffer from pollution, water abstraction, river channelisation and damming. Fundamental knowledge of ecosystem structure and function is necessary to understand how human acitivities interfere with natural processes and which interventions are feasible to rectify this. Modern water legislation strives for sustainable water resource management and protection of important habitats and species. However, decision makers would benefit from more profound understanding of ecosystem degradation processes and of innovative methodologies and tools for efficient mitigation and restoration. The book provides best-practice examples of sustainable river management from on-site studies, European-wide analyses and case studies from other parts of the world. This book will be of interest to researchers in the field of aquatic ecology, river system functioning, conservation and restoration, to postgraduate students, to institutions involved in water management, and to water related industries.

This book discusses the environmental impact of water resources projects. Information from literature related to the implementation of studies on water resources projects such as dams and reservoirs, channelization, and dredging are summarized. Other topics covered are methodologies, transport, and decision-making.

This book describes the entire process of environmental impact assessment for hydropower and dam projects, not from a legal or regulatory point of view, but from a very applied one, based mainly on the personal experience of the author, who is involved in this field of work since over 40 years, by describing the different steps of such an assessment, covering all major aspects to be dealt with. The focus is on environmental issues, while the other main subject—social impacts—is mentioned here only briefly. It will be of interest not only for ESIA (Environmental and Social Impact Assessment) practitioners, be they consultants involved in the preparation of such studies or staff members of environmental protection agencies having to come to decisions based on them, but also for engineers and planners involved in such projects, developers, and people interested in questions related to energy, environment, and climate change. Overall, this book aims at contributing to put the discussion about hydropower and dam projects on a more objective level.

Water resources stored by dams and reservoirs play an essential role in water resource management, hydropower and flood control. Where there is an extensive network of dam infrastructures, dams have made a major contribution to economic and social development, providing considerable storage capacity per capita. However, dams and reservoirs may also have an important social and environmental impact, and should be studied within the framework of integrated water resource management and sustainable development. Dams and Reservoirs, Societies and Environment in the 21st Century presents the latest research on the role played by dams and reservoirs in 21st century societies, in developed, emergent and developing countries. It analyses the viability of dams and suggests alternative solutions from a holistic perspective, considering the technical, economic, social and environmental aspects. Other issues covered include the social acceptability of dams, public involvement and dam awareness. The book covers subjects ranging from dam engineering, through the benefits and drawbacks of dams, to their social and environmental impact, and contains numerous case studies of the constructive contributions that reservoirs have made to water development and management. The book is a valuable resource for professional and dam engineers, water managers, governmental organizations and commercial enterprises responsible for dam development and management.