scholarly journals Efficiency and sustainability of gravel augmentation to restore large regulated rivers: Insights from three experiments on the Rhine River (France/Germany)

Geomorphology ◽  
2021 ◽  
Vol 380 ◽  
pp. 107639
Author(s):  
Valentin Chardon ◽  
Laurent Schmitt ◽  
Fanny Arnaud ◽  
Hervé Piégay ◽  
Anne Clutier
Keyword(s):  
Rhine River ◽  
Regulated Rivers

scholarly journals Effects of Transverse Groynes on Meso-Habitat Suitability for Native Fish Species on a Regulated By-Passed Large River: A Case Study along the Rhine River

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 987 ◽  
Author(s):  
Valentin Chardon ◽  
Laurent Schmitt ◽  
Hervé Piégay ◽  
Jean-Nicolas Beisel ◽  
Cybill Staentzel ◽  
...  
Keyword(s):  
Grain Size ◽  
Fish Species ◽  
Habitat Suitability ◽  
Habitat Diversity ◽  
Large River ◽  
Functional Restoration ◽  
Native Fish ◽  
Rhine River ◽  
Regulated Rivers ◽  
Fish Habitats

River regulations ultimately degrade fluvial forms and morphodynamics and simplify riparian and aquatic habitats. For several decades, river restoration actions have been performed to recover geomorphic processes and diversify these habitats to enhance both river biodiversity and ecosystem services. The objective of this study is to provide quantitative feedback on the experimental restoration of a large regulated and by-passed river (the Upper Rhine downstream of the Kembs Dam, France/Germany). This restoration consisted of the construction of two transverse groynes and the removal of bank protection. A monitoring framework composed of topo-bathymetric surveys as well as flow velocity and grain size measurements was established to assess the channel morphodynamic responses and evaluate their effects on habitat suitability for five native fish species using habitat models. A riverscape approach was used to evaluate the landscape changes in terms of both the configuration and the composition, which cannot be considered with classic approaches (e.g., Weighted Usable Area). Our results show that the two transverse groynes and, to a lesser extent, bank erosion, which was locally enhanced by the two groynes, increased habitat diversity due to the creation of new macroforms (e.g., pools and mid-bars) and fining of the bed grain size. Using a riverscape approach, our findings highlight that the restoration improved eel and juvenile nase species due to slowing down of the current and the deposition of fine sediments downstream of both groynes. As a consequence, the restoration improved the habitat suitability of the studied reach for more fish species compared with the pre-restoration conditions. This study also demonstrates that the salmon habitats downstream of the restored reach were improved due to fining of the bed grain size. This finding highlights that, for restorations aimed at fish habitats, the grain size conditions must be taken into consideration along with the flow conditions. Furthermore, the implementation of groynes, while not a panacea in terms of functional restoration, can be a strategy for improving fish habitats on highly regulated rivers, but only when more functional and natural options are impossible due to major constraints.

scholarly journals Slope Failure in a Period of Increased Landslide Activity: Sennwald Rock Avalanche, Switzerland

Geosciences ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 331
Author(s):  
Selçuk Aksay ◽  
Susan Ivy-Ochs ◽  
Kristina Hippe ◽  
Lorenz Grämiger ◽  
Christof Vockenhuber
Keyword(s):  
Slope Failure ◽  
Rock Avalanche ◽  
Eastern Alps ◽  
Rock Failure ◽  
Rhine River ◽  
Stratigraphic Sequence ◽  
Exposure Age ◽  
Wet Climate ◽  
Cosmogenic Nuclide Dating ◽  
Additional Support

The Säntis nappe is a complex fold-and-thrust structure in eastern Switzerland, consisting of numerous tectonic discontinuities and a range of hillslopes prone to landsliding and large slope failures that modify the topography irreversibly. A slope failure, namely the Sennwald rock avalanche, occurred in the southeast wall of this fold-and-thrust structure due to the rock failure of Lower Cretaceous Helvetic limestones along the Rhine River valley. In this research, this palaeolandslide is examined in a multidisciplinary approach for the first time with detection and mapping of avalanche deposits, dynamic run-out modelling and cosmogenic nuclide dating. During the rock failure, the avalanche deposits were transported down the hillslope in a spreading-deck fashion, roughly preserving the original stratigraphic sequence. The distribution of landslide deposits and surface exposure age of the rock failure support the hypothesis that the landslide was a single catastrophic event. The 36Cl surface exposure age of avalanche deposits indicates an age of 4.3 ± 0.5 ka. This time coincides with a notably wet climate period, noted as a conditioning factor for landslides across the Alps in the mid-Holocene. The contemporaneity of our event at its location in the Eastern Alps provide additional support for the contention of increased regional seismic activity in mid-Holocene.

Multidecadal dynamics of alternate bars in the Alpine Rhine River

2016 ◽  
Vol 52 (11) ◽  
pp. 8938-8955 ◽  
Author(s):  
Luca Adami ◽  
Walter Bertoldi ◽  
Guido Zolezzi
Keyword(s):  
Rhine River ◽  
Alternate Bars

scholarly journals 34 years of investigation in the Rhine River at Ludwigshafen, Germany – trends in Rhine fish populations

2012 ◽  
Vol 24 (1) ◽  
Author(s):  
Sascha Pawlowski ◽  
Juergen Jatzek ◽  
Thomas Brauer ◽  
Katja Hempel ◽  
Roland Maisch
Keyword(s):  
Fish Populations ◽  
Rhine River

scholarly journals Relative Contribution of the Xiaolangdi Dam to Runoff Changes in the Lower Yellow River

Land ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 521
Author(s):  
Qinghe Zhao ◽  
Shengyan Ding ◽  
Xiaoyu Ji ◽  
Zhendong Hong ◽  
Mengwen Lu ◽  
...  
Keyword(s):  
Climate Change ◽  
Human Activities ◽  
Sustainable Management ◽  
Yellow River ◽  
Dam Construction ◽  
Regulated Rivers ◽  
Flood Season ◽  
Abrupt Changes ◽  
Runoff Changes ◽  
Seasonal Runoff

Human activities are increasingly recognized as having a critical influence on hydrological processes under the warming of the climate, particularly for dam-regulated rivers. To ensure the sustainable management of water resources, it is important to evaluate how dam construction may affect surface runoff. In this study, using Mann–Kendall tests, the double mass curve method, and the Budyko-based elasticity method, the effects of climate change and human activities on annual and seasonal runoff were quantified for the Yellow River basin from 1961–2018; additionally, effects on runoff were assessed after the construction of the Xiaolangdi Dam (XLD, started operation in 2001) on the Yellow River. Both annual and seasonal runoff decreased over time (p < 0.01), due to the combined effects of climate change and human activities. Abrupt changes in annual, flood season, and non-flood season runoff occurred in 1986, 1989, and 1986, respectively. However, no abrupt changes were seen after the construction of the XLD. Human activities accounted for much of the reduction in runoff, approximately 75–72% annually, 81–86% for the flood season, and 86–90% for the non-flood season. Climate change approximately accounted for the remainder: 18–25% (annually), 14–19% (flood season), and 10–14% (non-flood season). The XLD construction mitigated runoff increases induced by heightened precipitation and reduced potential evapotranspiration during the post-dam period; the XLD accounted for approximately 52% of the runoff reduction both annually and in the non-flood season, and accounted for approximately −32% of the runoff increase in the flood season. In conclusion, this study provides a basic understanding of how dam construction contributes to runoff changes in the context of climate change; this information will be beneficial for the sustainable management of water resources in regulated rivers.

Emerging mitigation measures and strategies are needed for riverine ecology to ensure sustainable hydropeaking production in Norway 

2021 ◽  
Author(s):  
Jo Halvard Halleraker ◽  
Mahmoud S. R. Kenawi ◽  
Jan Henning L’Abée - Lund ◽  
Anders G. Finstad ◽  
Knut Alfredsen
Keyword(s):  
Biological Indicators ◽  
Ecological Impacts ◽  
Mitigation Strategies ◽  
Mitigation Measures ◽  
National Database ◽  
Political Agenda ◽  
Regulated Rivers ◽  
Hydropower Production ◽  
Multiple Pressures ◽  
Environmental Requirements

&lt;p&gt;&lt;strong&gt;Riverine biodiversity&lt;/strong&gt; is threatened with severe degradation from multiple pressures worldwide. One of the key pressures in European rivers are hydromorphological alterations. Rehabilitation of river habitats is accordingly high on the political agenda at the start of UN decade of ecological restoration (2021-2030).&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Water storage&lt;/strong&gt; for hydropower production (HP) has severe impacts on aquatic ecology in Norway, with more than 3000 water bodies designated as heavily modified due to hydropower. Norway is the largest hydropower producer in Europe with a huge amount of high head storage schemes. Ca 86 TWh of this is&amp;#160;storage hydropower, which constitutes more than 50% of the total in Europe. This makes Norway a potentially significant supplier of hydropeaking services. Flexible hydropower operations are crucial for EUs Green Deal in balancing electricity from renewable intermittent power generation such as wind and solar.&amp;#160;&lt;/p&gt;&lt;p&gt;Many Norwegian &lt;strong&gt;HP licenses&lt;/strong&gt; were issued before modern environmental requirements evolved. Few are re-licensed with emerging strategies to mitigate hydropeaking. Still, there seems to be a common understanding of relevant mitigation strategies emerging between many large hydropower producers. For example, flow ramping from hydropower tailrace water with direct outlet into fjords or other lake reservoirs may be less environmentally harmful than outlet into riverine habitat.In this study, we have assessed the Norwegian hydropower portfolio of more than 1600 HP facilities constructing a national database focusing on the knowledge base for assessing potential downstream hydropower ecological impacts. The ecological severity of such flow ramping and the restoration/mitigation potential, may depend on;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;About 51 % of the HPs (ca&lt;strong&gt; 80TWh&lt;/strong&gt;) have tailrace into shorter rivers (&lt;1 km) or directly into fjords or lake/reservoirs. Many of the largest HPs are in this category (e.g 50 HP&gt; 500 MW). Close to 800 HP might have downstream impacts on rivers (&gt; 0.5 km; about 49 % of all HP, in total of ca&lt;strong&gt; 56 TWh&lt;/strong&gt;). Probably &lt;strong&gt;&gt; 3 000 km of regulated rivers&lt;/strong&gt; in Norway therefor might need more ecosystem-based mode of HP operation.&amp;#160;&lt;strong&gt;Flow ramping analysis: &lt;/strong&gt;&amp;#160;Ecosystem-based HP operational rules are established in a selection of sustainably managed Norwegian rivers, still with significant baseload production (0.35-0.76 - TWh annual prod). However, eco-friendly mode of operation seems to be rare as our analysis indicate that flow ramping with potential ecological degradation seems widespread in many rivers. Surprisingly, even in many with operational ramping restriction as required mitigation.Our database may be further improved and updated (with e.g. more flow ramping data and biological indicators) and serve as a basis for a national hydropeaking strategy, and hence make more of the Norwegian hydropower portfolio in line with the EUs sustainability taxonomy.&lt;/p&gt;

Integrated water resources management in the Ruhr River Basin, Germany

2003 ◽  
Vol 47 (7-8) ◽  
pp. 81-86 ◽  
Author(s):  
H. Bode ◽  
P. Evers ◽  
D.R. Albrecht
Keyword(s):  
Water Resources ◽  
Water Supply ◽  
River Basin ◽  
Water Resources Management ◽  
Ecological Status ◽  
Integrated Water Resources Management ◽  
Rhine River ◽  
Wastewater Disposal ◽  
Resources Management ◽  
The People

The Ruhr, with an average flow of 80.5 m3/s at its mouth, is a comparatively small tributary to the Rhine River that has to perform an important task: to secure the water supply of more than 5 million people and of the industry in the densely populated region north of the river. The complex water management system and network applied by the Ruhrverband in the natural Ruhr River Basin has been developed step by step, over decades since 1913. And from the beginning, its major goal has been to achieve optimal conditions for the people living in the region. For this purpose, a functional water supply and wastewater disposal infrastructure has been built up. The development of these structures required and still requires multi-dimensional planning and performance. Since the river serves as receiving water and at the same time as a source of drinking water, the above-standard efforts of Ruhrverband for cleaner water also help to conserve nature and wildlife. Ruhrverband has summed up its environmental awareness in the slogan: “For the people and for the environment”. This basic water philosophy, successfully applied to the Ruhr for more than 80 years, will be continued in accordance with the new European Water Framework Directive, enacted in 2000, which demands integrated water resources management in natural river basins, by including the good ecological status of surface waterbodies as an additional goal.

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