Nutrient retention behind a tropical mega-dam: a case study of the Sardar Sarovar Dam, India

In this study, we demonstrate the impact of the construction of a mega-dam on the nutrient export regime of a large tropical river into the Arabian Sea. Long-term (11 years) fortnight nutrient parameters, upstream and downstream to Sardar Sarovar (SS) Dam, were examined to determine the periodical change in nutrient fluxes from the Narmada River, India. During this 11-year period, the average discharge of the Narmada River upstream to Rajghat (35.3 km3 year−1) was higher than that of downstream at Garudeshwar (33.9 km3 year−1). However, during the same period, the suspended sediment load was reduced by 21 million tons (MT) from 37.9 MT at Rajghat to 16.7 MT at Garudeshwar. Similarly, mean concentrations of dissolved silica (DSi) reduced from 470 (upstream) to 214 µM (downstream), dissolved inorganic phosphate (DIP) from 0.84 to 0.38 µM, and dissolved inorganic nitrogen (DIN) from 43 to 1.5 µM. It means that about 54%, 55%, and 96% flux of DSi, DIP, and DIN retained behind the dam, respectively. The estimated denitrification rate (80,000 kg N km−2 year−1) for the reservoir is significantly higher than N removal by lentic systems, globally. We hypothesize that processes such as biological uptake and denitrification under anoxic conditions could be a key reason for the significant loss of nutrients, particularly of DIN. Finally, we anticipated that a decline in DIN fluxes (by 1.13 × 109 mol year−1) from the Narmada River to the Arabian Sea might reduce the atmospheric CO2 fixation by 7.46 × 109 mol year−1.

Muddy Waters: Inside the World Bank as It Struggled with the Narmada Irrigation and Resettlement Projects, Western India

The period since the Second World War has witnessed three global power shifts: one, from sovereign states relating to each other through balances of power, to inter-state organizations which pool some sovereignty and enact collective preferences; two, from states to non-state organizations, including NGOs, enormously facilitated by the internet; and three, from West to East. The World Bank has been a microcosm of these shifts. This chapter describes the interplay between some of the agents: World Bank staff; World Bank top management; World Bank Executive Directors (representatives of member governments, who formally govern the Bank); Government of India and governments of states; Indian and international (mainly UK, US, Japanese) NGOs; and the US Congress. The context is the Narmada irrigation and resettlement projects in western India from the 1970s to the 1990s. The first of the projects (Sardar Sarovar) became the subject of a large-scale opposition movement, Indian and international, which ended up forcing the World Bank to take serious responsibility for resettlement and environmental sustainability in its projects world-wide, and to create an independent inspection facility to which people who consider their welfare net harmed by a World Bank-supported project can bring complaints direct to the Bank by-passing their national government.

Execution of Safe Blasting Under Adverse Conditions of a Powerhouse Complex: A Revisit to Sardar Sarovar Project, India

When the excavation of the underground powerhouse of the Sardar Sarovar Project, India was nearly complete, cracks were observed on the upstream and downstream walls of the powerhouse, and the installed instrumentation readings sounded an alert for the instability of the powerhouse cavern that could possibly derail the project, further excavation in the powerhouse cavern was halted. After completing stabilisation measures, the remaining underground excavations by drill and blast method were to be completed. This paper revisits case studies of controlled blasting for the remaining excavations, namely a construction ramp, turbine pits, draft tube tunnels connecting the powerhouse, and the concrete plugs erected at the exit ends of the draft tube tunnels. To ensure overall stability around the excavations, blast vibration was controlled by planning the excavations in proper sequences. The damage outside the planned line of excavations was controlled by adopting modified line drilling/smooth blasting techniques. The details of the sequence of excavations, drilling and blasting parameters, compiled from previous publications, are presented in this paper. This paper also describes the reasons why concrete plugs were erected in the draft tube tunnels, the details of the concrete plugs, the optimised drilling and blasting procedure for safe removal of the plugs, and the method adopted to quantify the damage.

Moving Beyond Economic Analysis: Assessing The Socio-Cultural Impacts Of Displacement And Resettlement By Sardar Sarovar Project, India

The large scale development projects like dams have been justified for a greater economic benefit of the nation. However, the development projects have become synonymous with land acquisition leading to dispossession and forced migration of a large number of people and their involuntary resettlement. Unfortunately, too much focus on the economic benefits of such large scale projects has omitted many relevant tangible and intangible socio-cultural aspects and ignored the impacts of development policies that shape forced migrations. The present paper asserts to move beyond the ‘limited’ economic analysis of large projects and includes the critical social and cultural implications of forced migration and displacement. The paper presents views of respondents displaced from the states of Gujarat, Madhya Pradesh and Maharashtra and were resettled inGujarat. Perhaps, it is the most unique aspect of this paper to understand the socio-cultural adjustment in context of the spatial origin. The resettlement caused by the Sardar Sarovar Project has led to a change in dress patterns and marriage customs, loss of tribal folk art, destroyed the existing social networks and hindered access to new ones. Increased violence against women, problem of drunkenness and bootlegging at the resettlement sites are also highlighted. The insights in the work are based upon the fieldwork in select resettlement sites inGujarat. The author adopted participant observation, focus group discussions and key informant interviews as a means for data collection and better comprehension of the study area.

Performance Evaluation Of The Hydropower Plants Using Various Multi-Criteria Decision-Making Techniques

Annual growth of 2.3 % since 1990 to 2017 in the hydropower sector in India indicates it holds a vital position in the growth of electricity generation in the country. For effective and efficient running of the hydropower projects, maintenance schedules and performance evaluation have to be done. Thus, this paper presents the performance evaluation of four different hydro-powerhouses belonging to a different class. Multi-criteria decision making (MCDM) method stepwise weight assessment ratio analysis (SWARA) is used to calculate the weights. The weights calculated by SWARA are employed to assess the performance scores or ranks of Indira Sagar Project (ISP), Canal Head Power House (CHPH) and River Bed Power House (RBPH) at Sardar Sarovar Narmada Nigam Ltd. (SSNNL) by integrating SWARA with the MCDM techniques like weighted aggregate sum product assessment (WASPAS), technique for order of preference by similarity to ideal solution (TOPSIS) and preference ranking organization method for enrichment evaluation (PROMETHEE). A comparative analysis of these integrated methods is presented for improved future studies in the area of decision making. The results in this paper show performance rankings of the available alternatives, calculated using integrated SWARA-WASPAS, SWARA-TOPSIS and SWARA-PROMETHEE methods. Performance ranks obtained by SWARA-WASPAS and SWARA-TOPSIS methods are in the order ISP, RBPH, CHPH and LSPH, which shows similarity with the on-field performances and are well suited for the performance evaluation of hydropower projects