Development of a regional model for hydropower potential in western Greece

2013 ◽  
Vol 14 (4) ◽  
pp. 442-449
Keyword(s):  
Regional Model ◽  
Flow Duration Curve ◽  
Drainage Basins ◽  
Flow Duration ◽  
Hydropower Potential ◽  
Flow Duration Curves ◽  
A Site ◽  
Northwestern Greece ◽  
Climatic Characteristics

A regional model was developed in the present study for the determination of the flow duration curve at ungaged catchments, in western and northwestern Greece, which is a hydrologically homogenous region. A flow duration curve indicates the water availability at a site and is important for the estimation of the hydropower potential. A flow duration curve was generated for each of seven available stations at different rivers and then the parameters of the flow duration curves were correlated with geomorphological and climatic characteristics of the drainage basins for the derivation of the equations of the regional model. The model was verified using three hold out stations, in which the error ranged from 0.3 to 1.1%.

scholarly journals The construction of the flow duration curve and the regionalization parameters analysis in the northwest of China

2021 ◽  
Author(s):  
Jinkai Luan ◽  
Dengfeng Liu ◽  
Mu Lin ◽  
Qiang Huang
Keyword(s):  
Distribution Functions ◽  
Coefficient Of Determination ◽  
Flow Duration Curve ◽  
Suitable Model ◽  
Ungauged Catchments ◽  
Flow Duration ◽  
Distribution Parameters ◽  
Flow Duration Curves ◽  
Log Normal ◽  
Climatic Characteristics

Abstract Daily runoff is the data to estimate the water resources in a river. In many catchments, the daily discharge is not well observed. Flow duration curve is an important characteristic of daily runoff, and important for the design of water conservancy projects. In the ungauged catchments, the evaluation of distribution functions and the parameters of flow duration curve is a helpful method to understand the characteristics of the flow. This study uses data from 19 hydrological stations to evaluate the applicability of 11 distribution functions to simulate flow duration curves in the northwest of China. The fitted flow duration curves are evaluated by Nash-Sutcliffe efficiency, the root mean square relative error and the coefficient of determination. The evaluation shows that, among the 11 distribution functions, the log normal model is the most suitable model to construct flow duration curves of 19 hydrological stations. Based on a multivariate linear regression model, a regional model of distribution parameters is constructed, including functions of watershed geomorphologic and climatic characteristics. The analysis of Baijiachuan hydrological station shows that the parameters a and b showed a decreasing trend. This study presents an innovative approach to evaluate regionalized parameters of flow duration curves considering the impacts of geomorphologic and climatic characteristics.

scholarly journals Catchment classification by runoff behaviour with self-organizing maps (SOM)

2011 ◽  
Vol 8 (2) ◽  
pp. 3047-3083 ◽  
Author(s):  
R. Ley ◽  
M. C. Casper ◽  
H. Hellebrand ◽  
R. Merz
Keyword(s):  
Cluster Analysis ◽  
Ungauged Catchments ◽  
Self Organizing Maps ◽  
Response Behaviour ◽  
Flow Duration ◽  
Wide Range ◽  
Spatio Temporal ◽  
Flow Duration Curves ◽  
Climatic Characteristics ◽  
Self Organizing

Abstract. Catchments show a wide range of response behaviour, even if they are adjacent. For many purposes it is necessary to characterise and classify them, e.g. for regionalisation, prediction in ungauged catchments, model parameterisation. In this study, we investigate hydrological similarity of catchments with respect to their response behaviour. We analyse more than 8200 event runoff coefficients (ERCs) and flow duration curves of 53 gauged catchments in Rhineland-Palatinate, Germany, for the period from 1993 to 2008, covering a huge variability of weather and runoff conditions. The spatio-temporal variability of event-runoff coefficients and flow duration curves are assumed to represent how different catchments "transform" rainfall into runoff. From the runoff coefficients and flow duration curves we derive 12 signature indices describing various aspects of catchment response behaviour to characterise each catchment. Hydrological similarity of catchments is defined by high similarities of their indices. We identify, analyse and describe hydrologically similar catchments by cluster analysis using Self-Organizing Maps (SOM). As a result of the cluster analysis we get five clusters of similarly behaving catchments where each cluster represents one differentiated class of catchments. As catchment response behaviour is supposed to be dependent on its physiographic and climatic characteristics, we compare groups of catchments clustered by response behaviour with clusters of catchments based on catchment properties. Results show an overlap of 67% between these two pools of clustered catchments which can be improved using the topologic correctness of SOMs.

A Method Based on Taking the Average of Probabilities to Compute the Flow Duration Curve

2000 ◽  
Vol 31 (3) ◽  
pp. 187-206 ◽  
Author(s):  
Hikmet Kerem Cigizoglu
Keyword(s):  
Probability Distributions ◽  
Maximum Flow ◽  
Exceedance Probability ◽  
Flow Duration Curve ◽  
Marginal Probability ◽  
Lognormal Distributions ◽  
Type Iii ◽  
Flow Duration ◽  
Pearson Type ◽  
Flow Duration Curves

In this study a method based on taking the average of the probabilities is presented to obtain flow duration curve. In this method the exceedance probability for each flow value is computed repeatedly for all time periods within a year. The final representing exceedance is just simply the average of all these probabilities. The applicability of the method to daily mean flows is tested assuming various marginal probability distributions like normal, Pearson type III, log-Pearson type III, 2-parameter lognormal and 3-parameter lognormal distributions. It is seen that the observed flow duration curves were quite well approximated by the 2-parameter lognormal average of probabilities curves. In that case the method requires the computation of the daily mean and standard deviation values of the observed flow data. The method curve enables extrapolation of the available data providing the exceedance probabilities for the flows higher than the observed maximum flow. The method is applied to the missing data and ungauged site problems and the results are quite satisfactory.

scholarly journals Catchment classification by runoff behaviour with self-organizing maps (SOM)

2011 ◽  
Vol 15 (9) ◽  
pp. 2947-2962 ◽  
Author(s):  
R. Ley ◽  
M. C. Casper ◽  
H. Hellebrand ◽  
R. Merz
Keyword(s):  
Cluster Analysis ◽  
Ungauged Catchments ◽  
Self Organizing Maps ◽  
Response Behaviour ◽  
Flow Duration ◽  
Wide Range ◽  
Spatio Temporal ◽  
Flow Duration Curves ◽  
Climatic Characteristics ◽  
Self Organizing

Abstract. Catchments show a wide range of response behaviour, even if they are adjacent. For many purposes it is necessary to characterise and classify them, e.g. for regionalisation, prediction in ungauged catchments, model parameterisation. In this study, we investigate hydrological similarity of catchments with respect to their response behaviour. We analyse more than 8200 event runoff coefficients (ERCs) and flow duration curves of 53 gauged catchments in Rhineland-Palatinate, Germany, for the period from 1993 to 2008, covering a huge variability of weather and runoff conditions. The spatio-temporal variability of event-runoff coefficients and flow duration curves are assumed to represent how different catchments "transform" rainfall into runoff. From the runoff coefficients and flow duration curves we derive 12 signature indices describing various aspects of catchment response behaviour to characterise each catchment. Hydrological similarity of catchments is defined by high similarities of their indices. We identify, analyse and describe hydrologically similar catchments by cluster analysis using Self-Organizing Maps (SOM). As a result of the cluster analysis we get five clusters of similarly behaving catchments where each cluster represents one differentiated class of catchments. As catchment response behaviour is supposed to be dependent on its physiographic and climatic characteristics, we compare groups of catchments clustered by response behaviour with clusters of catchments based on catchment properties. Results show an overlap of 67% between these two pools of clustered catchments which can be improved using the topologic correctness of SOMs.

scholarly journals A methodology to estimate flow duration curves at partially ungauged basins

2020 ◽  
Vol 24 (4) ◽  
pp. 2043-2060
Author(s):  
Elena Ridolfi ◽  
Hemendra Kumar ◽  
András Bárdossy
Keyword(s):  
Time Window ◽  
Donor Site ◽  
Main Idea ◽  
Weather Conditions ◽  
Target Time ◽  
Flow Duration ◽  
The Usa ◽  
Flow Duration Curves ◽  
A Site ◽  
Gauged Basins

Abstract. The flow duration curve (FDC) of streamflow at a specific site has a key role in the knowledge on the distribution and characteristics of streamflow at that site. The FDC gives information on the water regime, providing information to optimally manage the water resources of the river. In spite of its importance, because of the lack of streamflow gauging stations, the FDC construction can be a not straightforward task. In partially gauged basins, FDCs are usually built using regionalization among the other methods. In this paper we show that the FDC is not a characteristic of the basin only, but of both the basin and the weather. Different weather conditions lead to different FDCs for the same catchment. The differences can often be significant. Similarly, the FDC built at a site for a specific period cannot be used to retrieve the FDC at a different site for the same time window. In this paper, we propose a new methodology to estimate FDCs at partially gauged basins (i.e., target sites) using precipitation data gauged at another basin (i.e., donor site). The main idea is that it is possible to retrieve the FDC of a target period of time using the data gauged during a given donor time period for which data are available at both target and donor sites. To test the methodology, several donor and target time periods are analyzed and results are shown for different sites in the USA. The comparison between estimated and actually observed FDCs shows the reasonability of the approach, especially for intermediate percentiles.

scholarly journals Archimedes Screw Design: An Analytical Model for Rapid Estimation of Archimedes Screw Geometry

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7812
Author(s):  
Arash YoosefDoost ◽  
William David Lubitz
Keyword(s):  
Single Equation ◽  
Relative Difference ◽  
Hydropower Plant ◽  
Local Flow ◽  
Rapid Estimation ◽  
Screw Design ◽  
Initial Design ◽  
Flow Duration Curves ◽  
A Site

In designing Archimedes screws, determination of the geometry is among the fundamental questions that may affect many aspects of the Archimedes screw powerplant. Most plants are run-of-river and highly depend on local flow duration curves that vary from river to river. An ability to rapidly produce realistic estimations for the initial design of a site-specific Archimedes screw plant helps to facilitate and accelerate the optimization of the powerplant design. An analytical method in the form of a single equation was developed to rapidly and easily estimate the Archimedes screw geometry for a specific site. This analytical equation was developed based on the accepted, proved or reported common designs characteristics of Archimedes screws. It was then evaluated by comparison of equation predictions to existing Archimedes screw hydropower plant installations. The evaluation results indicate a high correlation and reasonable relative difference. Use of the equation eliminates or simplifies several design steps and loops and accelerates the development of initial design estimations of Archimedes screw generators dramatically. Moreover, it helps to dramatically reduce one of the most significant burdens of small projects: the nonscalable initial investigation costs and enables rapid estimation of the feasibility of Archimedes screw powerplants at many potential sites.

scholarly journals A methodology to estimate flow duration curves at partially ungauged basins

2018 ◽  
Author(s):  
Elena Ridolfi ◽  
Hemendra Kumar ◽  
András Bárdossy
Keyword(s):  
Time Window ◽  
Main Idea ◽  
Weather Conditions ◽  
Target Time ◽  
Flow Duration ◽  
Time Period ◽  
Target Period ◽  
Flow Duration Curves ◽  
Set Up ◽  
A Site

Abstract. The Flow Duration Curve (FDC) set up at a specific site has a key role to the knowledge of the streamflow characteristic at that site. The FDC gives information on the water regime providing important information to optimally manage the water resources of the river. Spite of its importance, because of the lack of streamflow gauging stations, the FDC construction can be a not straightforward task. In ungauged or partially gauged catchments, FDCs are usually built using regionalization methods among the others. In this paper we show that the FDC is not a characteristic of the basin only, but of both the basin and the weather. Different weather conditions lead to different FDC for the same catchment. The differences can often be significant. Similarly, the FDC built at a site for a specific period of time cannot be used to retrieve the FDC at a different site for the same time window. In this paper we propose a new methodology to estimate FDCs at partially gauged basins (i.e., target sites) using discharge and precipitation data gauged at another catchment (i.e., reference catchment). The main idea is that it is possible to retrieve the FDC of a target period of time using the data gauged during a given reference time period for which data are available at both target and reference sites. To test the methodology, several reference and target time periods are analysed and results are shown for two different case study areas. The comparison between estimated and actually observed FDCs show the reasonability of the approach especially for intermediate percentiles.

RNA secondary structure dependence in METTL3–METTL14 mRNA methylation is modulated by the N-terminal domain of METTL3

2020 ◽  
Vol 402 (1) ◽  
pp. 89-98
Author(s):  
Nathalie Meiser ◽  
Nicole Mench ◽  
Martin Hengesbach
Keyword(s):  
Secondary Structure ◽  
Rna Binding ◽  
Specific Protein ◽  
Structure Dependence ◽  
Terminal Domain ◽  
Methylation Assay ◽  
A Site ◽  
Methylation Activity

AbstractN6-methyladenosine (m6A) is the most abundant modification in mRNA. The core of the human N6-methyltransferase complex (MTC) is formed by a heterodimer consisting of METTL3 and METTL14, which specifically catalyzes m6A formation within an RRACH sequence context. Using recombinant proteins in a site-specific methylation assay that allows determination of quantitative methylation yields, our results show that this complex methylates its target RNAs not only sequence but also secondary structure dependent. Furthermore, we demonstrate the role of specific protein domains on both RNA binding and substrate turnover, focusing on postulated RNA binding elements. Our results show that one zinc finger motif within the complex is sufficient to bind RNA, however, both zinc fingers are required for methylation activity. We show that the N-terminal domain of METTL3 alters the secondary structure dependence of methylation yields. Our results demonstrate that a cooperative effect of all RNA-binding elements in the METTL3–METTL14 complex is required for efficient catalysis, and that binding of further proteins affecting the NTD of METTL3 may regulate substrate specificity.

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