More Like this

1. Sustainable hydropower in the 21st century

   https://doi.org/10.1073/pnas.1809426115  

   Moran, Emilio F.; Lopez, Maria Claudia; Moore, Nathan; Müller, Norbert; Hyndman, David W. (November 2018, Proceedings of the National Academy of Sciences)

   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. 

   more » « less
2. Optimizing Amazonian dams for nature

   https://doi.org/10.1126/science.abn8311  

   Holtgrieve, Gordon W.; Arias, Mauricio E. (February 2022, Science)

   Large river systems, particularly those shared by developing nations in the tropics, exemplify the interconnected and thorny challenges of achieving sustainability with respect to food, energy, and water ( 1 ). Numerous countries in South America, Africa, and Asia have committed to hydropower as a means to supply affordable energy with net-zero emissions by 2050 ( 2 ). The placement, size, and number of dams within each river basin network have enormous consequences for not only the ability to produce electricity ( 3 ) but also how they affect people whose livelihoods depend on the local river systems ( 4 ). On page 753 of this issue, Flecker et al. ( 5 ) present a way to assess a rich set of environmental parameters for an optimization analysis to efficiently sort through an enormous number of possible combinations for dam placements and help find the combination(s) that can achieve energy production targets while minimizing environmental costs in the Amazon basin. 

   more » « less
3. Changes in Social Capital Associated with the Construction of the Belo Monte Dam: Comparing a Resettled and a Host Community

   https://doi.org/10.17730/1938-3525-81.1.22  

   Mayer, Adam; Lopez, Maria Claudia; Leturcq, Guillaume; Moran, Emilio (February 2022, Human Organization)

   Nations in the Global South have increasingly embraced large hydropower. Hydropower development typically involves the displacement and resettlement of entire communities and has a range of social and ecological impacts. Some communities become the operational center for the dam construction, as well as host new neighborhoods of resettlers. One of the less-studied impacts of dams is the potential loss of social capital both in resettled and host communities. Here, we ask how the Belo Monte dam in the Amazon is associated with social capital in a resettled group and a non-resettled population that, while not experiencing resettlement, nevertheless was impacted by the dam as well. We use measures of cognitive and structural social capital. Results suggest that resettlers have lower structural social capital across two proxy indicators, whereas the host community has lower cognitive social capital. Future research and social impact assessments should pay more attention to how hydropower impacts both kinds of social capital. 

   more » « less
4. A Meta-Analysis of Environmental Tradeoffs of Hydropower Dams in the Sekong, Sesan, and Srepok (3S) Rivers of the Lower Mekong Basin

   https://doi.org/10.3390/w13010063  

   Null, Sarah E.; Farshid, Ali; Goodrum, Gregory; Gray, Curtis A.; Lohani, Sapana; Morrisett, Christina N.; Prudencio, Liana; Sor, Ratha (January 2021, Water)

   null (Ed.)

   In Mekong riparian countries, hydropower development provides energy, but also threatens biodiversity, ecosystems, food security, and an unparalleled freshwater fishery. The Sekong, Sesan, and Srepok Rivers (3S Basin) are major tributaries to the Lower Mekong River (LMB), making up 10% of the Mekong watershed but supporting nearly 40% of the fish species of the LMB. Forty-five dams have been built, are under construction, or are planned in the 3S Basin. We completed a meta-analysis of aquatic and riparian environmental losses from current, planned, and proposed hydropower dams in the 3S and LMB using 46 papers and reports from the past three decades. Proposed mainstem Stung Treng and Sambor dams were not included in our analysis because Cambodia recently announced a moratorium on mainstem Mekong River dams. More than 50% of studies evaluated hydrologic change from dam development, 33% quantified sediment alteration, and 30% estimated fish production changes. Freshwater fish diversity, non-fish species, primary production, trophic ecology, and nutrient loading objectives were less commonly studied. We visualized human and environmental tradeoffs of 3S dams from the reviewed papers. Overall, Lower Sesan 2, the proposed Sekong Dam, and planned Lower Srepok 3A and Lower Sesan 3 have considerable environmental impacts. Tradeoff analyses should include environmental objectives by representing organisms, habitats, and ecosystems to quantify environmental costs of dam development and maintain the biodiversity and extraordinary freshwater fishery of the LMB. 

   more » « less
5. USING THE MATERIAL POINT METHOD TO EXAMINE POST-EARTHQUAKE STABILITY OF SLOPES AND EMBANKMENT DAMS

   Montgomery, Jack; Murphy, John (April 2024, United States Society on Dams)

   Earthquake-related failure modes for embankment dams are commonly evaluated through numerical simulations using finite element or finite difference approaches. This is especially true for liquefaction triggering or cyclic softening of fine-grained materials where advanced constitutive models are used to capture the dynamic response of the dam and the nonlinear behavior of the soil. Both liquefaction and cyclic softening can lead to significant strength loss, which can lead to large deformations within the dam, but these numerical tools often cannot capture these large deformations due to excessive mesh distortion and subsequent numerical errors. This leads to significant uncertainties in estimating potential crest settlement, which is often a critical value for risk assessments of dams. Hybrid numerical methods like the material point method (MPM) offer a promising alternative to model large deformations, but their application to dams is still limited and relatively little validation has been done on using MPM for post-earthquake stability analyses. This study focuses on applying MPM simulations to evaluate the post-earthquake stability of a hypothetical embankment dam and to examine potential deformations of a flowslide that occurred in Palu, Indonesia in 2018. The MPM program Anura3D is used for the analyses with modifications to allow for assigning residual strengths. The results from the Palu flowslide are compared with observations from the field to show that the MPM analyses are able to capture the extent of the slide, but underpredict the measured displacements in the central portion of the flowslide. The analyses for the embankment dam are compared with post-earthquake stability results from finite difference analyses using FLAC. The MPM analyses are able to capture the full deformation of the flowslide, while the FLAC analyses are halted due to excessive mesh deformation. These results demonstrate the potential of MPM to be used as a complement to existing numerical tools for evaluating the seismic response of dams, but additional work is needed to validate this approach using case histories with both large and small deformations. 

   more » « less