Migrations of Young Fish in Regulated Rivers: Effects of Ecological Filters (Review)

AbstractAssemblages of juvenile fish and associated abiotic parameters were investigated inside and outside Jinju Bay in southern Korea, on a monthly basis from December 2014 to November 2015. Fluctuations in water temperature and salinity were larger inside than outside the bay. In total, 534,657 individuals per square kilometre from 81 fish species and 47 families were collected during the study period. The most dominant species was Nuchequula nuchalis both inside (25.6%) and outside (26.9%) the bay. The next dominant species were Thryssa kammalensis (17.9%) and Zoarces gillii (16.0%) inside the bay and Liparis tanakae (16.9%) and T. kammalensis (9.0%) outside the bay. Forty species (33% of total number of individuals) of young fish were recorded inside the bay and 47 species (52%) outside the bay. Therefore, it appears that a diversity of fish use nursery grounds inside and outside Jinju Bay. In particular, the following six species appeared: Z. gillii, Pleuronichthys cornutus, L. tanakae, Hemitripterus villosus, Pennahia argentata, and Xenocephalus elongates. Due to assemblage differences for fishes within Jinju Bay and outside the bay, management of both areas is required to maintain current diversity of species in the region.

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Generation of natural daily flow time-series in regulated rivers using a non-linear spatial interpolation technique

Regulated Rivers Research & Management ◽

10.1002/(sici)1099-1646(199907/08)15:4<311::aid-rrr544>3.0.co;2-w ◽

1999 ◽

Vol 15 (4) ◽

pp. 311-323 ◽

Cited By ~ 40

Author(s):

V.Y. Smakhtin

Keyword(s):

Time Series ◽

Spatial Interpolation ◽

Flow Time ◽

Regulated Rivers ◽

Interpolation Technique ◽

Non Linear

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A self‐correction technique for real‐time simulation of regulated rivers

International Journal of Water Resources Development ◽

10.1080/07900629208722562 ◽

1992 ◽

Vol 8 (4) ◽

pp. 248-256

Author(s):

Olcay I. Unver

Keyword(s):

Real Time ◽

Regulated Rivers ◽

Real Time Simulation ◽

Time Simulation ◽

Correction Technique

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

Land ◽

10.3390/land10050521 ◽

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.

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

10.5194/egusphere-egu21-16429 ◽

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

Riverine biodiversity 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).Water storage 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&#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.&#160;Many Norwegian HP licenses 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;&#160;About 51 % of the HPs (ca 80TWh) have tailrace into shorter rivers (<1 km) or directly into fjords or lake/reservoirs. Many of the largest HPs are in this category (e.g 50 HP> 500 MW). Close to 800 HP might have downstream impacts on rivers (> 0.5 km; about 49 % of all HP, in total of ca 56 TWh). Probably > 3 000 km of regulated rivers in Norway therefor might need more ecosystem-based mode of HP operation.&#160;Flow ramping analysis: &#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.

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