ASSESSMENT OF HYDROLOGICAL CHANGES IN THE ŠUŠVĖ RIVER

2015 ◽  
Author(s):  
Gražina ŽIBIENĖ ◽  
Alvydas ŽIBAS ◽  
Goda BLAŽAITYTĖ
Keyword(s):  
Hydrological Regime ◽  
Maximum Flow ◽  
Environmental Flow ◽  
Physical Structure ◽  
River Channels ◽  
Hydrologic Alteration ◽  
Water Conditions ◽  
Flow Components ◽  
The Impact ◽  
Large Floods

The construction of dams in rivers negatively affects ecosystems because dams violate the continuity of rivers, transform the biological and physical structure of the river channels, and the most importantly – alter the hydrological regime. The impact on the hydrology of the river can occur through reducing or increasing flows, altering seasonality of flows, changing the frequency, duration and timing of flow events, etc. In order to determine the extent of the mentioned changes, The Indicators of Hydrologic Alteration (IHA) software was used in this paper. The results showed that after the construction of Angiriai dam, such changes occurred in IHA Parameters group as: the water conditions of April month decreased by 31 %; 1-day, 3-days, 7-days and 30-days maximum flow decreased; the date of minimum flow occurred 21 days later; duration of high and low pulses and the frequency of low pulses decreased, but the frequency of high pulses increased, etc. The analysis of the Environmental Flow Components showed, that the essential differences were recorded in groups of the small and large floods, when, after the establishment of the Šušvė Reservoir, the large floods no longer took place and the probability of frequency of the small floods didn’t exceed 1 time per year.

scholarly journals Statistical analysis of maximum runoff of the Southern Buh River using the method of ‘Indicators of Hydrologic Alteration’

2021 ◽  
pp. 42-54
Author(s):  
L. O. Gorbachova ◽  
V. S. Prykhodkina ◽  
B. F. Khrystiuk ◽  
T. O. Zabolotnia ◽  
V. O. Rozlach
Keyword(s):  
Practical Importance ◽  
Hydrological Regime ◽  
Statistical Characteristics ◽  
Hydrologic Alteration ◽  
Municipal Water Supply ◽  
Regime Changes ◽  
Total Runoff ◽  
High Runoff ◽  
Large Floods ◽  
Maximum Runoff

Knowledge of maximum river runoff trends is of great practical importance, especially for design and operation of hydraulic structures. This article presents the results of the research of the Southern Buh River's maximum runoff. The water of the river is widely used for hydropower engineering, industrial and municipal water supply, agriculture, irrigation, shipping, tourism etc. The research of the maximum runoff was based on the Indicators of Hydrologic Alteration (IHA) method which is widely used in the whole world. This method enables calculation of quantitative statistical characteristics of rivers', lakes', reservoirs' runoff and determination of the degree of their hydrological regime changes. The IHA is used for water bodies having natural or regulated runoff. However, the IHA method was not widely used in Ukraine before. The purpose of this publication is using the Indicators of Hydrologic Alterations method in order to study the characteristics of maximum runoff and their changes along the Southern Buh River. The research was carried out based on the data of observations at 5 gauge stations located along the Southern Buh River. The research uses the mean daily discharges that has been recorded since the beginning of observations up to 2018 and 2019 inclusive. The river's runoff at each of gauge stations was divided into five components: "Extremely low runoff", "Low runoff", "High runoff pulses", "Small floods", "Large floods". This made it possible to separate three classes of high (maximum) runoff, for which the IHA statistics were calculated, from the total runoff. It was discovered that the long-term high runoff changes differed in each of its three components, although they had general trends. The most significant changes were found for large floods, with no significant changes found for high runoff pulses. General trends of high runoff showed that over time the values of maximum discharges tend to decrease, with the increasing duration of high runoff periods. The values of the main statistical indicators of high runoff gradually increase from the river's source to its mouth, which fully corresponds to the physical and geographical conditions of its formation. Nevertheless, some features of high runoff were still found. Thus small floods and high runoff pulses have the largest duration in the upper reach of the river. On average, the Southern Buh River experiences large floods once in every 10 years, small floods - once in every 2 years, high runoff pulses - 4-8 times a year in its upper reach and 9-14 times a year in its middle reach.

scholarly journals Hydrological Foundation as a Basis for a Holistic Environmental Flow Assessment of Tropical Highland Rivers in Ethiopia

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 547 ◽  
Author(s):  
Wubneh B. Abebe ◽  
Seifu A. Tilahun ◽  
Michael M. Moges ◽  
Ayalew Wondie ◽  
Minychl G. Derseh ◽  
...  
Keyword(s):  
Flow Regime ◽  
Current Flow ◽  
Environmental Flow ◽  
High Flow ◽  
Low Flow ◽  
Trend Test ◽  
Floodplain Wetlands ◽  
Low Flows ◽  
Flow Components ◽  
Large Floods

The sustainable development of water resources includes retaining some amount of the natural flow regime in water bodies to protect and maintain aquatic ecosystem health and the human livelihoods and wellbeing dependent upon them. Although assessment of environmental flows is now occurring globally, limited studies have been carried out in the Ethiopian highlands, especially studies to understand flow-ecological response relationships. This paper establishes a hydrological foundation of Gumara River from an ecological perspective. The data analysis followed three steps: first, determination of the current flow regime—flow indices and ecologically relevant flow regime; second, naturalization of the current flow regime—looking at how flow regime is changing; and, finally, an initial exploration of flow linkages with ecological processes. Flow data of Gumara River from 1973 to 2018 are used for the analysis. Monthly low flow occurred from December to June; the lowest being in March, with a median flow of 4.0 m3 s−1. Monthly high flow occurred from July to November; the highest being in August, with a median flow of 236 m3 s−1. 1-Day low flows decreased from 1.55 m3 s−1 in 1973 to 0.16 m3 s−1 in 2018, and 90-Day (seasonal) low flow decreased from 4.9 m3 s−1 in 1973 to 2.04 m3 s−1 in 2018. The Mann–Kendall trend test indicated that the decrease in low flow was significant for both durations at α = 0.05. A similar trend is indicated for both durations of high flow. The decrease in both low flows and high flows is attributed to the expansion of pump irrigation by 29 km2 and expansion of plantations, which resulted in an increase of NDVI from 0.25 in 2000 to 0.29 in 2019. In addition, an analysis of environmental flow components revealed that only four “large floods” appeared in the last 46 years; no “large flood” occurred after 1988. Lacking “large floods” which inundate floodplain wetlands has resulted in early disconnection of floodplain wetlands from the river and the lake; which has impacts on breeding and nursery habitat shrinkage for migratory fish species in Lake Tana. On the other hand, the extreme decrease in “low flow” components has impacts on predators, reducing their mobility and ability to access prey concentrated in smaller pools. These results serve as the hydrological foundation for continued studies in the Gumara catchment, with the eventual goal of quantifying environmental flow requirements.

scholarly journals Evaluation of Reservoir-Induced Hydrological Alterations and Ecological Flow Based on Multi-Indicators

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 2069 ◽  
Author(s):  
Mingqian Li ◽  
Xiujuan Liang ◽  
Changlai Xiao ◽  
Xuezhu Zhang ◽  
Guiyang Li ◽  
...  
Keyword(s):  
Hydrological Regime ◽  
Ecological Indicators ◽  
Shannon Index ◽  
Low Flow ◽  
Ecological Diversity ◽  
Human Beings ◽  
Hydrologic Alteration ◽  
Flow Duration ◽  
The Impact ◽  
The Relationship

Although they fulfill various needs of human beings, reservoirs also cause hydrological regime variation in the downstream regions, thus affecting ecological diversity. Therefore, studying the reservoir-induced hydrological alterations and ecological effects is of great significance, as it could guide the regulation of the reservoir to protect the river ecology. In this study, taking the Taizi River as an example, the impact of a reservoir on hydrological alteration and ecological diversity was comprehensively evaluated through eco-flow indicators based on the flow duration curve and multiple hydrological indicators. The results reveal that: (1) Ecological indicators can be used to analyze the annual and seasonal changes in the streamflow after the construction of the reservoir. The high-flow values and frequency decrease after the construction of the reservoir, especially in the autumn, while the low-flow component values increase significantly, especially in spring and summer. (2) The main influencing factors of the ecological indicators can be reflected by the relationship with precipitation, as the annual ecosurplus is not significantly affected by the reservoir, while the ecodeficit is greatly affected, and the seasonal ecological indicators (especially in spring and summer) are greatly affected by the reservoir. (3) The indicators of hydrologic alteration (IHA) show significant changes after the construction of the reservoir and are consistent with the changes in the eco-flow indicators; the change in the Shannon index indicates that the ecological diversity reduced after construction of the reservoir. It is controlled by the reservoir, and a new equilibrium state appears. (4) The eco-flow indicators have a good correlation with the 32 IHAs; they can reflect the change information of most IHAs and can avoid statistical redundancy.

scholarly journals Identification of the degree of impact of dams on the hydrologic regime of semi-arid rivers: an evaluation of the DHRAM method

RBRH ◽  
2017 ◽  
Vol 22 (0) ◽  
Author(s):  
Naiah Caroline Rodrigues de Souza ◽  
◽  
Andrea Sousa Fontes ◽  
Lafayette Dantas da Luz ◽  
Sandra Maria Conceição Pinheiro ◽  
...  
Keyword(s):  
Hydrological Regime ◽  
Flow Regulation ◽  
Hydrologic Regime ◽  
Local Conditions ◽  
Operating Rules ◽  
Hydrologic Variability ◽  
High Degree ◽  
The Impact ◽  
Semi Arid

ABSTRACT The flow regulation that results from the implantation of dams causes consequences to the river ecosystems due to the modification on the characteristics of the hydrologic regime. The investigation of these changes become relevant, mainly in semi-arid regions where there is a great amount of these hydraulic structures and lack of such analyzes. Considering the above, this paper aims to evaluate the Dundee Hydrological Regime Alteration Method (DHRAM) through the classification of the degree of impact of dams located on rivers Itapicuru, Paraguaçu and their tributaries, verifying the adequacy of its use to represent the semi-arid hydrologic regime. Thereby, the DHRAM was applied in three versions: considering the thresholds that define the scores to classify the degree of impact in its original set (accordingly to Black et al. (2005)); with the adjustment of those thresholds to local conditions; and, with the regrouping of variables and adjustment of thresholds. The results showed that the method in its original set is applicable to semi-arid rivers, however it tends to be very restrictive against the high natural hydrologic variability characteristic of these rivers, and it ends up pointing to a high degree of alteration for dams that are known for not causing a very siginifcant flow regulation. The DHRAM with the regrouping of variables and the adjustment of thresholds presented the classification that approached the most to the known characteristics of the studied dams, being useful for the evaluation of the impact of dams still in project, and also to guide the adoption of operating rules that minimize the most significant hydrologic alterations that are identified.

Dependence of efficiency of natural fish reproduction in water bodies of Kazakhstan from water level

2021 ◽  
pp. 32-41
Author(s):  
K.B. Isbekov ◽  
E.V. Kulikov ◽  
S.Zh. Asylbekova
Keyword(s):  
Water Content ◽  
Water Regime ◽  
Juvenile Fish ◽  
Hydrological Regime ◽  
Water Bodies ◽  
Fish Reproduction ◽  
Data Set ◽  
Commercial Fish ◽  
Level Of Significance ◽  
The Impact

The article deals with the relationship between the hydrological regime of water bodies and the efficiency of fish reproduction. The hydrological regime of water bodies in years of different water content influences the reproduction and, accordingly, the quantitative and qualitative composition of ichthyocenoses. The easiest way to assess the efficiency of fish reproduction is by such an indicator as the productivity of juveniles, i.e. the number of juvenile fish per unit area or volume. The material for this work was carried out in large fishing reservoirs of the Republic of Kazakhstan in the process of fishery research (2013–2018). Comparison of hydrological parameters and productivity of juveniles by years shows their relationship. Correlation coefficient between water content (runoff) of the river Zhaiyk and juvenile yield +0.73 (data set for 11 years, reliable for the level of significance p = 0.01). The yield of juvenile fish from Lake Balkhash has a high correlative dependence on the inflow of water into the lake (r = +0.826) (massif 2013–2018, reliable for the level of significance p = 0.05). Correlation analysis showed that the productivity of juvenile fish in the Kapshagai reservoir has an average degree of dependence on water content (average annual level) (r = +0.641, reliable for the level of significance p = 0.05). Regular relationships between the water regime and the efficiency of reproduction (productivity of juveniles) of fish have been established. The efficiency of natural reproduction of commercial fish species in modern conditions of the water regime, water withdrawal for economic needs and the impact of fishing is significantly reduced, but with the implementation of the reclamation measures proposed in the work, its partial restoration is possible.

The Impact of Rural Finance on Rural Economic Development from the Perspective of Efficiency of Discrete Differential Algorithm

2021 ◽  
Vol 7 (5) ◽  
pp. 4358-4365
Author(s):  
Mingxu Peng ◽  
Jiawen Huang
Keyword(s):  
Economic Growth ◽  
Rural Economy ◽  
Choice Model ◽  
Influence Factors ◽  
Maximum Flow ◽  
Pso Algorithm ◽  
Significant Degree ◽  
Theoretical Research ◽  
The Impact ◽  
The Relationship

Objectives: Finance is the core of the national economy. The development of modern rural economy is inseparable from financial support. The relationship between finance and economic growth has always been one of the hot topics in theoretical research and empirical analysis. Methods: Under the background of the development of Internet e-commerce, the maximum flow algorithm was based on the empirical research on the relationship between China’s financial development and economic growth. Results: Based on this, the two-element discrete choice model of Probit and Logistic for economic growth was constructed. Discrete particle swarm optimization (PSO) algorithm was used to estimate the parameters of the model. The significant degree of the influence factors was calculated. Conclusion: Finally, it was calculated that concurrent business was the decisive factor of economic growth.

Comparison of mayfly (Ephemeroptera) taxocenes of permanent and intermittent Central European small streams via species traits

Biologia ◽  
2010 ◽  
Vol 65 (4) ◽  
Author(s):  
Pavla Řezníčková ◽  
Tomáš Soldán ◽  
Petr Pařil ◽  
Světlana Zahrádková
Keyword(s):  
Global Climate ◽  
Extreme Temperature ◽  
Oxygen Demand ◽  
Hydrological Regime ◽  
Species Traits ◽  
Individual Species ◽  
Biological Traits ◽  
Small Streams ◽  
High Oxygen Demand ◽  
The Impact

AbstractThe recurrent drying out of small streams in past decades has shown an urgent need to pay attention to the impact of global climate change. The objectives of this study were to describe the effect of drying out on the composition of the mayfly taxocene and evaluate the relevance of individual species traits for survival of mayflies to drying out. The mayfly taxocenes of two model localities, one at an intermittent and one at a permanent brook, were investigated in 2002, 2003 and 2005. Compared with the permanent stream, the taxocene of the intermittent stream was short of nine species, foremost rheobionts and high oxygen demand species. To explain further differences between both stream types in survival and recolonisation ability, 15 species traits were evaluated. These included so-called “ecological traits” (e.g., habitat and substrate range, density, distribution, current velocity adaptation) and “biological traits” connected with life cycle and larval/adult adaptations. Species showing the highest number of advantageous traits (with only exception of Electrogena sp. cf. ujhelyii — species of taxonomically unclear status) were able to successfully survive under the unfavourable conditions of the intermittent brook. Biological traits considered more important in many respects seem to be good predictors for assessing sensitivity to extreme temperature changes, hydrological regime fluctuations and the survival/recolonisation ability of species in exposed habitats.

scholarly journals Analysis of Climate Change in the Area of Vojvodina-Republic of Serbia and Possible Consequences

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Mirko Andreja Borisov
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Hydrological Regime ◽  
Factors Affecting ◽  
Digital Terrain ◽  
Wide Range ◽  
Digital Terrain Modeling ◽  
Nature And Society ◽  
The Impact ◽  
Linear Correlations

Climate change conditions a wide range of impacts such as the impact on weather, but also on ecosystems and biodiversity, agriculture and forestry, human health, hydrological regime and energy. In addition to global warming, local factors affecting climate change are being considered. Presentation and analysis of the situation was carried out using geoinformation technologies (radar recording, remote detection, digital terrain modeling, cartographic visualization and geostatistics). This paper describes methods and use of statistical indicators such as LST, NDVI and linear correlations from which it can be concluded that accelerated construction and global warming had an impact on climate change in period from 1987 to 2018 in the area of Vojvodina – Republic of Serbia. Also, using the global SRTM DEM, it is shown how the temperature behaves based on altitude change. Conclusions and possible consequences in nature and society were derived.

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