A critical view on the eco-friendliness of small hydroelectric installations

An Environmental Flow Framework for Riverine Macroinvertebrates During Dry and Wet Seasons Through Non-linear Ecological Modeling

A suitable environmental flow is critical for the functional maintenance of riverine ecosystems. Hydropower plants alter the flow regime by decreasing or even drying up the streamflow downstream of the dams, thereby affecting ecosystem sustainability. In this study, we aimed to develop a robust environmental flow framework that can provide scientific evidence for sustainable water resource management. Using ecological niche modeling based on non-linear responses of species to habitat factors, we assessed the environmental flow in the Xiangxi River Basin of Central China during dry and wet seasons from a multi-year perspective. The most abundant macroinvertebrate taxon (i.e., Baetis) was selected for model testing. The results showed seasonal differences in the minimum ecological water requirements and optimal environmental flow. These two hydrological metrics were higher during the wet season than during the dry season. During the dry season, the minimum ecological water requirement of Baetis was 1.3 m3·s−1, and the optimal environmental flow was 1.6 m3·s−1. During the wet season, the minimum ecological water requirement of Baetis was 2.5 m3·s−1, and the optimal environmental flow was 2.6 m3·s−1. This study provides a theoretical basis for the robust management of water resources in river basins.

Stakeholder Management and Project Sustainability—A Throw of the Dice

The aim of this study was to analyze the strategies that external stakeholders apply to influence sustainable projects. In order to investigate this phenomenon, we employed a qualitative case study approach considering the Serbian small hydro power plant project. For the purpose of this research, we developed a theoretical framework consisting of four types of different influence strategies, which were identified and then applied to our case. The results show that external stakeholders utilized all four strategies interchangeably, with the goal to influence the project and decision-makers. The case of the small hydro power plant project revealed certain relationships between influence strategies, as well as the intensity and direction of these relationships. It also revealed that external stakeholders were highly motivated by negative impacts on the environment. Five propositions were derived as a result of our research. This paper contributes not just to the project and stakeholder management literature but also to the practical knowledge of project managers. Understanding stakeholder actions and influence is essential to achieving project goals.

Analysis of Hydrologic Regime Changes Caused by Small Hydropower Plants in Lowland Rivers

Hydropower remains the most important and largest source of renewable energy. However, besides many additional benefits, such as dams for water supply, irrigation, flood control, recreation, navigation, etc., hydropower generation has a negative impact on the environment. This study aimed to investigate the hydrologic changes in Lithuanian lowland rivers caused by small hydropower plants (HPPs). Thirty-two indicators of hydrologic alteration (IHA) were studied in 11 rivers downstream of hydropower plants in the post-impact and pre-impact periods. The findings showed that HPPs and reservoirs considerably disturbed the primary flow of river ecosystems downstream. The largest changes in mean IHA values were found for low and high pulse characteristics (up to 57%) and the number of reversals (up to 44%). Only small or no deviations of the timing of annual extreme flows were found. The number of reversals, a low pulse count, and a fall rate were the flow characteristics that fell outside their historical ranges of variability most often. Six (out of 11) hydropower plants were identified that provoked hydrologic alterations of a moderate degree.

Assessment of the Impact of Small Hydropower Plants on the Ecological Status Indicators of Water Bodies: A Case Study in Lithuania

Hydropower plants produce renewable and sustainable energy but affect the river’s physico-chemical characteristics and change the abundance and composition of the aquatic organisms. The impact of large HPPs on the ecological conditions of surface water bodies have been extensively studied, but less attention has been paid to environmental impact studies of small hydropower plants (SHPs). The impact of hydropeaking on both the river flow regime and ecosystems has been well-studied for peaking mode plants, mainly medium to large-sized ones. However, for small hydroelectric power plants, and especially for those in lowland rivers, the available information on water quality, benthic macroinvertebrates communities and fish abundance, and biomass is not sufficient. Ten small hydropower plants were selected, and the ecological status of water bodies was assessed in different parts of Lithuania. The studies were performed at the riverbed upstream from the SHPs, where the hydrological regime has not changed, and downstream from the SHPs. It was found that the small hydropower plants do not affect the physico-chemical values of the water quality indicators. This study demonstrated that the total number of benthic macroinvertebrates taxa (TS) is influenced by the concentration of nitrogen and suspended solids, the water flow, the river area, and the current speed; the number of EPT (Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies)) taxa is influenced by the concentration of nitrogen and suspended solids. The studied indicators do not have a significant impact on biomass. The SHPs affect the fish abundance and biomass. The Lithuanian fish index (LFI) is influenced by the average depth and area of the river. Some SHPs operating in lowland areas may yield somewhat significant hydrograph ramping but more detailed investigation is needed to support the significance of this impact on the biological indices.

A Model to Forecast Methane Emissions from Topical and Subtropical Reservoirs on the Basis of Artificial Neural Networks

In view of the great paucity of information on the exact contributions of different causes which lead to different extents of emission of the greenhouse gas methane (CH4) form reservoirs, it is tremendously challenging to develop statistical or analytical models for forecasting such emissions. Artificial neural networks (ANNs) have the ability to discern linear or non-linear relationships despite very limited data inputs and can recognize even complex patterns in a data set without a priori understating of the underlying mechanism. Hence, we have used ANNs to develop a model linking CH4 emissions to five of the reservoir parameters about which data is most commonly available in the prior art. Using a compendium of all available data on these parameters, of which a small part was kept aside for use in model validation, it has been possible to develop a model which is able to forecast CH4 emissions with a root mean square error of 37. It indicates a precision significantly better than the ones achieved in previous reports. The model provides a means to estimate CH4 emissions from reservoirs of which age, mean depth, surface area, latitude and longitude are known.

New lake in a changing world: the construction and filling of a small hydropower reservoir in the tropics (Rio de Janeiro, Brazil)

Climate change has affected rainfall patterns in tropical regions, where simultaneous demands for water and energy, habitat loss, declining biodiversity, and spread of invasive species have reflected a rapidly changing world underway. In Brazil, hydropower generation accounts for 64% of the electricity matrix, which presently includes 1007 small hydropower plants (SHPs) having many others under construction or planned. This paper aimed to evaluate changes in water quality, plankton communities, and benthic macroinvertebrates during dam construction, filling, and the first year of operation of a SHP. Suspended solids, turbidity, and silica were variables that highlighted the impact of this construction on the river. Fast changes in water quality (increases in calcium, chlorides, and nitrate) and on aquatic communities (i.e. euglenophyceans and testate amoebae increased in numbers) were detected during the filling phase. Following SHP construction, the concentrations of metals and total phosphorus tended to decrease. Two striking findings observed in the aquatic communities from the riverine conditions to the new lake were the increase in picocyanobacteria abundance, expanding population stocks throughout the river basin, and the constant presence of the invasive mollusc Corbicula fluminea in the macroinvertebrate assemblage, revealing once again its resistance to environmental variability. The lake soon became a natural trap for ions from the drainage basin, as revealed by the increase in electrical conductivity, ammonium, potassium, and magnesium concentrations and the abundance of cyanobacteria, highlighting the need for watershed management to improve ecological conditions in the lake.

Potential of joyweed Alternanthera sessilis for rapid treatment of domestic sewage in SHEFROL® bioreactor

In a first-ever report on this subject, it is shown that a common amphibious plant joyweed (Alternanthera sessilis) can be used in rapid and efficient treatment of biodegradable wastewaters, typified by domestic sewage. The plant was effective when used indoors under artificial lighting, as well as outdoors. It enabled treatment of sewage, varying widely in strength (from 300 mg/L to 1800 mg/L in chemical oxygen demand), to the extent of 78.9-83.9%. It was also able to remove biological oxygen demand, suspended solids, phosphorous, nitrogen, and the heavy metal copper to the extent of 87%, 93%, 45%, and 43%, respectively. Over 99% of total coliforms, faecal coliforms, and faecal streptococci were also removed. The treatment was very swiftly achieved, at a hydraulic retention time of just 6 h, in the "sheet flow root level" (SHEFROL^®) bioreactor developed earlier by us and of which a patent claim has been registered. The findings indicate that A. sessilis has the potential to affect primary, secondary, and tertiary treatment of domestic sewage along with significant pathogen removal in a single process step when used in SHEFROL^® bioreactors.

Sustainable hydropower in the 21st century

Hydropower has been the leading source of renewable energy across the world, accounting for up to 71% of this supply as of 2016. This capacity was built up in North America and Europe between 1920 and 1970 when thousands of dams were built. Big dams stopped being built in developed nations, because the best sites for dams were already developed and environmental and social concerns made the costs unacceptable. Nowadays, more dams are being removed in North America and Europe than are being built. The hydropower industry moved to building dams in the developing world and since the 1970s, began to build even larger hydropower dams along the Mekong River Basin, the Amazon River Basin, and the Congo River Basin. The same problems are being repeated: disrupting river ecology, deforestation, losing aquatic and terrestrial biodiversity, releasing substantial greenhouse gases, displacing thousands of people, and altering people's livelihoods plus affecting the food systems, water quality, and agriculture near them. This paper studies the proliferation of large dams in developing countries and the importance of incorporating climate change into considerations of whether to build a dam along with some of the governance and compensation challenges. We also examine the overestimation of benefits and underestimation of costs along with changes that are needed to address the legitimate social and environmental concerns of people living in areas where dams are planned. Finally, we propose innovative solutions that can move hydropower toward sustainable practices together with solar, wind, and other renewable sources.

Potential impact of small hydroelectric power plants on river biota: a case study on macroinvertebrates associated to basaltic knickzones

Small hydroelectric power plants (SHP) have been considered as an alternative for the generation of electricity with reduced environmental impacts. Nevertheless, no studies have addressed changes in a particular kind of river macrohabitat commonly affected by SHPs, the knickzones. This study aimed to assess the impact of a SHP construction on the aquatic macroinvertebrate fauna associated with two basaltic knickzones located in Sapucaí-Mirim River, Southeast Brazil. The first, considered as a functional knickzone, follows the natural dynamics of the river flow and preserves the original rock substrate. The second, considered as non-functional knickzone, was permanently flooded after the SHP construction and the consolidated rock substrate was changed by fine sediment. Sampling was carried out in two seasonal periods and the data were analysed through multivariate analysis. It was observed differences in composition and structure of the macroinvertebrates community between the knickzones and periods. The functional knickzone exhibited a much higher richness, 72 taxa compared to 44 in the non-functional, as well as a large number of exclusive taxa (38, being only nine exclusive to the non-functional). Diversity, equitability and density mean values were also higher in the functional knickzone. The limnological parameters varied significantly between dry and rainy seasons but not between the distinct knickzones. This kind of macrohabitats and its potential role for the rivers biodiversity is practically unknown. In the scenery of fast SHP expansion, further studies and protection measures are necessary.

A new methodology for royalties distribution of the Itaipu hydroelectric plant: The hydrographic basin as the unit of analysis

Over the past few years, many sectors such as energy generation, industry, domestic supply, and agriculture have encountered serious environmental problems due to the lack of rainfall. Thus, the purpose of this paper is to review the current methodology of royalties distribution from Itaipu hydroelectric plant. In the proposed approach, two criteria were considered to establish the division of Itaipu royalties: (1) the relative percentage of the water flow in the generation of electricity and, (2) the relative percentage of the drop in the height of water. 62 hydroelectric plants were evaluated in this study. In 52 plants the water flow was the factor that most contributed to the generation of electricity. In 2013, 346 municipalities benefited the Itaipu royalties. With the proposed methodology, 1,327 municipalities will receive the resource, what would increase the revenue of each of these municipalities by, on average, US$ 87,436.91 per year. The methodology presented herein proposes a reduction in the environmental disparity that now exists in Brazil, through improvement to Government instruments and environmental policies. The distribution of royalties throughout the watershed can provide additional resources to support payment programs for environmental services at the state and municipality levels.

The changing hydrology of a dammed Amazon

Developing countries around the world are expanding hydropower to meet growing energy demand. In the Brazilian Amazon, >200 dams are planned over the next 30 years, and questions about the impacts of current and future hydropower in this globally important watershed remain unanswered. In this context, we applied a hydrologic indicator method to quantify how existing Amazon dams have altered the natural flow regime and to identify predictors of alteration. The type and magnitude of hydrologic alteration varied widely by dam, but the largest changes were to critical characteristics of the flood pulse. Impacts were largest for low-elevation, large-reservoir dams; however, small dams had enormous impacts relative to electricity production. Finally, the "cumulative" effect of multiple dams was significant but only for some aspects of the flow regime. This analysis is a first step toward the development of environmental flows plans and policies relevant to the Amazon and other megadiverse river basins.

Itaipu royalties: The role of the hydroelectric sector in water resource management

For countries dependent on hydroelectricity, water scarcity poses a real risk. Hydroelectric plants are among the most vulnerable enterprises to climate change. Investing in the conservation of the hydrographic basin is a solution found by the hydropower sector. Given the importance of the Itaipu plant to the energy matrix of Brazil and Paraguay, the aim of this study is to review the current distribution of royalties from Itaipu, using the hydrographic basin as a of criterion of analysis. Approximately 98.73% of the Itaipu basin is in Brazil. The flow contributes 99% of the total electricity generated there, while the drop height of the water contributes only 1%. Under the current policy, royalties are shared equally between Brazil and Paraguay. In the proposed approach, each country would receive a percentage for their participation in the drop height and water flow in the output of the turbines, which are intrinsic factors for electricity generation. Thus, Brazil would receive 98.35% of the royalties and Paraguay, 1.65%. The inclusion of the hydrographic basin as a criterion for the distribution of royalties will promote more efficient water resource management, since the payment will be distributed throughout the basin of the plant. The methodology can be applied to hydroelectric projects worldwide.

A cautionary approach in transitioning to 'green' energy technologies and practices is required

Renewable energy technologies (wind turbines, solar cells, biofuels, etc.) are often referred to as 'clean' or 'green' energy sources, while jobs linked to the field of environmental protection and energy efficiency are referred to as 'green' jobs. The energy efficiency of clean technologies, which is likely to reduce and/or eliminate reliance on fossil fuels, is acknowledged. However, the potential contribution of green technologies and associated practices to ill health and environmental pollution resulting from consumption of energy and raw materials, generation of waste, and the negative impacts related to some life cycle phases of these technologies are discussed. Similarly, a point is made that the green jobs theme is mistakenly oversold because the employment opportunities generated by transitioning to green technologies are not necessarily safe and healthy jobs. Emphasis is put on identifying the hazards associated with these green designs, assessing the risks to the environment and worker health and safety, and either eliminating the hazards or minimizing the risks as essential elements to the design, construction, operation, and maintenance of green technologies. The perception that it is not always economically possible to consider all risk factors associated with renewable energy technologies at the beginning without hampering their implementation, especially in the poor developing countries, is dismissed. Instead, poor countries are encouraged to start implementing environmentally sound practices while transitioning to green technologies in line with their technological development and overall economic growth.