scholarly journals Analysis of the Uncertainty in Estimates of Manning’s Roughness Coefficient and Bed Slope Using GLUE and DREAM

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3270
Author(s):  
Guilherme da Cruz dos Reis ◽  
Tatiane Souza Rodrigues Pereira ◽  
Geovanne Silva Faria ◽  
Klebber Teodomiro Martins Formiga
Keyword(s):  
Statistical Analysis ◽  
River Discharge ◽  
Roughness Coefficient ◽  
Hydraulic Parameters ◽  
Relative Deviation ◽  
Discharge Data ◽  
Resources Management ◽  
Manning’S Roughness Coefficient ◽  
Bed Slope ◽  
Engineering Projects

River discharge data are critical to elaborating on engineering projects and water resources management. Discharge data must be precise and collected with good temporal resolution. To elaborate on a more accurate database, this paper aims to quantify the uncertainty generated while applying Bayesian inference through the GLUE and DREAM methods. Both methods were used to estimate hydraulic parameters and compare between them with Manning’s equation. Throughout the statistical analysis, the uncertainties in the application of the models are used to determine the parameters of Manning’s roughness coefficient and bed slope. The validation was made via a comparison of the calculated maximum and minimum discharges, and the observed flow available at HidroWeb. In conclusion, both methods estimated the hydraulic parameters well, but a higher relative deviation was seen in the intervals with smaller calculated discharges; DREAM appears to be more accurate than GLUE, once the relative deviation in GLUE became greater.

scholarly journals Overland Flow Resistance Law under Sparse Stem Vegetation Coverage

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1657
Author(s):  
Jingzhou Zhang ◽  
Shengtang Zhang ◽  
Si Chen ◽  
Ming Liu ◽  
Xuefeng Xu ◽  
...  
Keyword(s):  
Flow Resistance ◽  
Overland Flow ◽  
Vegetation Coverage ◽  
Dominant Factor ◽  
Roughness Coefficient ◽  
Hydraulic Parameters ◽  
Slope Condition ◽  
Manning Roughness ◽  
The Relationship ◽  
Manning Roughness Coefficient

To explore the characteristics of overland flow resistance under the condition of sparse vegetative stem coverage and improve the basic theoretical research of overland flow, the resistance characteristics of overland flow were systematically investigated under four slope gradients (S), seven flow discharges (Q), and six degrees of vegetation coverage (Cr). The results show that the Manning roughness coefficient (n) changes with the ratio of water depth to vegetation height (h/hv) while the Reynolds number (Re), Froude number (Fr), and slope (S) are closely related to vegetation coverage. Meanwhile, h/hv, Re, and Cr have strong positive correlations with n, while Fr and S have strong negative correlations with n. Through data regression analysis, a power function relationship between n and hydraulic parameters was observed and sensitivity analysis was performed. It was concluded that the relationship between n and h/hv, Re, Cr, Q, and S shows the same law; in particular, for sparse stem vegetation coverage, Cr is the dominant factor affecting overland flow resistance under zero slope condition, while Cr is no longer the first dominant factor affecting overland flow resistance under non-zero slope condition. In the relationship between n and Fr, Cr has the least effect on overland flow resistance. This indicates that when Manning roughness coefficient is correlated with different hydraulic parameters, the same vegetation coverage has different effects on overland flow resistance. Therefore, it is necessary to study overland flow resistance under the condition of sparse stalk vegetation coverage.

Improving SAR Altimeter processing over the coastal zone and inland waters - the ESA HYDROCOASTAL project

2021 ◽  
Author(s):  
David Cotton ◽  
Keyword(s):  
Coastal Zone ◽  
Test Data ◽  
River Discharge ◽  
Altimeter Data ◽  
Inland Waters ◽  
Data Sets ◽  
Data Set ◽  
Discharge Data ◽  
Processing Algorithms ◽  
The Impact

<p><strong>Introduction</strong></p><p>HYDROCOASTAL is a two year project funded by ESA, with the objective to maximise exploitation of SAR and SARin altimeter measurements in the coastal zone and inland waters, by evaluating and implementing new approaches to process SAR and SARin data from CryoSat-2, and SAR altimeter data from Sentinel-3A and Sentinel-3B. Optical data from Sentinel-2 MSI and Sentinel-3 OLCI instruments will also be used in generating River Discharge products.</p><p>New SAR and SARin processing algorithms for the coastal zone and inland waters will be developed and implemented and evaluated through an initial Test Data Set for selected regions. From the results of this evaluation a processing scheme will be implemented to generate global coastal zone and river discharge data sets.</p><p>A series of case studies will assess these products in terms of their scientific impacts.</p><p>All the produced data sets will be available on request to external researchers, and full descriptions of the processing algorithms will be provided</p><p> </p><p><strong>Objectives</strong></p><p>The scientific objectives of HYDROCOASTAL are to enhance our understanding  of interactions between the inland water and coastal zone, between the coastal zone and the open ocean, and the small scale processes that govern these interactions. Also the project aims to improve our capability to characterize the variation at different time scales of inland water storage, exchanges with the ocean and the impact on regional sea-level changes</p><p>The technical objectives are to develop and evaluate  new SAR  and SARin altimetry processing techniques in support of the scientific objectives, including stack processing, and filtering, and retracking. Also an improved Wet Troposphere Correction will be developed and evaluated.</p><p><strong>Project  Outline</strong></p><p>There are four tasks to the project</p><ul><li>Scientific Review and Requirements Consolidation: Review the current state of the art in SAR and SARin altimeter data processing as applied to the coastal zone and to inland waters</li> <li>Implementation and Validation: New processing algorithms with be implemented to generate a Test Data sets, which will be validated against models, in-situ data, and other satellite data sets. Selected algorithms will then be used to generate global coastal zone and river discharge data sets</li> <li>Impacts Assessment: The impact of these global products will be assess in a series of Case Studies</li> <li>Outreach and Roadmap: Outreach material will be prepared and distributed to engage with the wider scientific community and provide recommendations for development of future missions and future research.</li> </ul><p> </p><p><strong>Presentation</strong></p><p>The presentation will provide an overview to the project, present the different SAR altimeter processing algorithms that are being evaluated in the first phase of the project, and early results from the evaluation of the initial test data set.</p><p> </p>

scholarly journals Toward continental hydrologic–hydrodynamic modeling in South America

2018 ◽  
Vol 22 (9) ◽  
pp. 4815-4842 ◽  
Author(s):  
Vinícius A. Siqueira ◽  
Rodrigo C. D. Paiva ◽  
Ayan S. Fleischmann ◽  
Fernando M. Fan ◽  
Anderson L. Ruhoff ◽  
...  
Keyword(s):  
South America ◽  
Land Surface ◽  
River Discharge ◽  
Hydrological Modeling ◽  
Water Levels ◽  
Scale Model ◽  
Global Models ◽  
Discharge Data ◽  
Continental Scale ◽  
Terrestrial Water

Abstract. Providing reliable estimates of streamflow and hydrological fluxes is a major challenge for water resources management over national and transnational basins in South America. Global hydrological models and land surface models are a possible solution to simulate the terrestrial water cycle at the continental scale, but issues about parameterization and limitations in representing lowland river systems can place constraints on these models to meet local needs. In an attempt to overcome such limitations, we extended a regional, fully coupled hydrologic–hydrodynamic model (MGB; Modelo hidrológico de Grandes Bacias) to the continental domain of South America and assessed its performance using daily river discharge, water levels from independent sources (in situ, satellite altimetry), estimates of terrestrial water storage (TWS) and evapotranspiration (ET) from remote sensing and other available global datasets. In addition, river discharge was compared with outputs from global models acquired through the eartH2Observe project (HTESSEL/CaMa-Flood, LISFLOOD and WaterGAP3), providing the first cross-scale assessment (regional/continental  ×  global models) that makes use of spatially distributed, daily discharge data. A satisfactory representation of discharge and water levels was obtained (Nash–Sutcliffe efficiency, NSE > 0.6 in 55 % of the cases) and the continental model was able to capture patterns of seasonality and magnitude of TWS and ET, especially over the largest basins of South America. After the comparison with global models, we found that it is possible to obtain considerable improvement on daily river discharge, even by using current global forcing data, just by combining parameterization and better routing physics based on regional experience. Issues about the potential sources of errors related to both global- and continental-scale modeling are discussed, as well as future directions for improving large-scale model applications in this continent. We hope that our study provides important insights to reduce the gap between global and regional hydrological modeling communities.

scholarly journals Usos múltiplos da água por usuários outorgados nas bacias hidrográficas dos Rios Aguapeí e Peixe

2021 ◽  
Vol 14 (4) ◽  
pp. 2172-2185
Author(s):  
Fernanda Buono da Silva ◽  
Timóteo Ramos Queiroz ◽  
Denilson Burkert ◽  
Rodrigo Lilla Manzione
Keyword(s):  
Statistical Analysis ◽  
Water Resources ◽  
Water Resources Management ◽  
Rural Areas ◽  
Descriptive Statistics ◽  
Resources Management ◽  
Multiple Uses ◽  
The Right ◽  
The Relationship ◽  
Water Uses

The growing demand for water resources can generate conflicts between different users. To this end, water resources management instruments were implemented, in particular the granting of the right to use, which prioritize the multiple and rational use of water. The work was carried out with the objective of analyzing the profile and the distribution of water uses granted in relation to socioeconomic aspects in the municipalities that make up the Hydrographic Basins Committee of the Aguapeí and Peixe Rivers (CBH-AP). Grant data from 58 municipalities with which descriptive statistics were analysed and prepared for the discussion on the scenario of the multiple uses of water granted. Subsequently, the data were given to the multiple regression statistical analysis, in which the relationship between the number of grants per municipality and its socioeconomic parameters was analyzed. The results demonstrated the grants in the municipalities that comprise an area covered by the Hydrographic Basins Committee of the Aguapeí and Peixe rivers are mainly related to the use of groundwater in rural areas. In the three municipalities (Bastos, Dracena and Tupã) concentrate 26% of the analyzed grants. The increase in MHDI and population, at the same time, stimulates the growth in the number of grants. Thus, there is a need to implement public policies that collaborate directly or indirectly to increase the regularization of water use.

scholarly journals Automated calibration of a two-dimensional overland flow model by estimating Manning's roughness coefficient using genetic algorithm

2017 ◽  
Vol 20 (2) ◽  
pp. 440-456
Author(s):  
J. Drisya ◽  
D. Sathish Kumar
Keyword(s):  
Genetic Algorithm ◽  
Flow Model ◽  
Overland Flow ◽  
Fitness Function ◽  
Roughness Coefficient ◽  
Model Parameters ◽  
Automatic Data ◽  
Automated Calibration ◽  
Manning’S Roughness Coefficient ◽  
Overland Flow Model

Abstract Calibration is an important phase in the hydrological modelling process. In this study, an automated calibration framework is developed for estimating Manning's roughness coefficient. The calibration process is formulated as an optimization problem and solved using a genetic algorithm (GA). A heuristic search procedure using GA is developed by including runoff simulation process and evaluating the fitness function by comparing the experimental results. The model is calibrated and validated using datasets of Watershed Experimentation System. A loosely coupled architecture is followed with an interface program to enable automatic data transfer between overland flow model and GA. Single objective GA optimization with minimizing percentage bias, root mean square error and maximizing Nash–Sutcliffe efficiency is integrated with the model scheme. Trade-offs are observed between the different objectives and no single set of the parameter is able to optimize all objectives simultaneously. Hence, multi-objective GA using pooled and balanced aggregated function statistic are used along with the model. The results indicate that the solutions on the Pareto-front are equally good with respect to one objective, but may not be suitable regarding other objectives. The present technique can be applied to calibrate the hydrological model parameters.

scholarly journals Manning’s roughness coefficient for the Doce River

RBRH ◽  
2018 ◽  
Vol 23 (0) ◽  
Author(s):  
Emmanuel Kennedy da Costa Teixeira ◽  
Márcia Maria Lara Pinto Coelho ◽  
Eber José de Andrade Pinto ◽  
Jéssica Guimarães Diniz ◽  
Aloysio Portugal Maia Saliba
Keyword(s):  
River Flow ◽  
Hydraulic Modeling ◽  
Roughness Coefficient ◽  
Local Approach ◽  
Water Courses ◽  
Time Variations ◽  
The Subject ◽  
Manning’S Roughness Coefficient ◽  
Doce River ◽  
Water Depths

ABSTRACT The Manning’s roughness coefficient is used for various hydraulic modeling. However, the decision on what value to adopt is a complex task, especially when dealing with natural water courses due to the various factors that affect this coefficient. For this reason, most of the studies carried out on the subject adopt a local approach, such as this proposal for the Doce River. Due to the regional importance of this river in Brazil, the objective of this article was to estimate the roughness coefficient of Manning along the river, in order to aid in hydraulic simulations, as well as to discuss the uncertainties and variations associated with this value. For this purpose, information on flow rates and water depths were collected at river flow stations along the river. With this information, the coefficients were calculated using the Manning equation, using the software Canal, and their space-time variations were observed. In addition, it was observed that the uncertainties in flow and depth measurements affect the value of the Manning coefficient in the case studied.

Manning's roughness coefficient for ecological subsurface channel with modules

2019 ◽  
Vol 18 (3) ◽  
pp. 349-361 ◽  
Author(s):  
Reza Mohammadpour ◽  
Muhammad Kashfy Zainalfikry ◽  
Nor Azazi Zakaria ◽  
Aminuddin Ab. Ghani ◽  
Ngai Weng Chan
Keyword(s):  
Roughness Coefficient ◽  
Manning’S Roughness Coefficient

scholarly journals Simulation of river discharge in ungauged catchments by forcing GLDAS products to a hydrological model (a case study: Polroud basin, Iran)

2019 ◽  
Vol 20 (1) ◽  
pp. 277-286
Author(s):  
Hadis Pakdel Khasmakhi ◽  
Majid Vazifedoust ◽  
Safar Marofi ◽  
Abdollah Taheri Tizro
Keyword(s):  
River Discharge ◽  
Good Alternative ◽  
Observation Data ◽  
Ungauged Catchments ◽  
Discharge Data ◽  
The North ◽  
Temperature And Precipitation ◽  
North Of Iran ◽  
Land Data Assimilation ◽  
Land Data Assimilation System

Abstract Due to unavailability of sufficient discharge data for many rivers, an appropriate approach is required to provide accurate data for estimating discharge in ungauged watersheds. In this study, Global Land Data Assimilation System (GLDAS) datasets were integrated with Hydrologic Engineering Center Hydrologic Modeling System (HEC-HMS) to simulate the outlet river discharge in Polroud watershed, located in the North of Iran. Temperature and precipitation products generated by GLDAS were calibrated using regression analysis based on observation data for the period of 2004–2006. Then, river discharge was simulated by using HEC-HMS based on two different datasets (GLDAS meteorological product and gauged data) on the scale of the basin for the same period. The results clearly indicated that the forcing of GLDAS data into HEC-HMS model leads to promising results with acceptable correlation with observed data. Although, in comparison with direct GLDAS runoff products, the proposed approach improved the accuracy of river discharge, the problem of underestimation still reduces the expected accuracy. Because of global accessibility, GLDAS datasets would be a good alternative in ungauged or poorly gauged watersheds.

Changes in Latvian river discharge regime at the turn of the century

2012 ◽  
Vol 44 (3) ◽  
pp. 554-569 ◽  
Author(s):  
Elga Apsīte ◽  
Ilze Rudlapa ◽  
Inese Latkovska ◽  
Didzis Elferts
Keyword(s):  
River Runoff ◽  
River Discharge ◽  
Large Scale ◽  
Hydrological Regime ◽  
Turn Of The Century ◽  
Significant Trend ◽  
Low Flow ◽  
Data Series ◽  
Discharge Data ◽  
Baltic Countries

The study deals with turn-of-the-century changes in the total annual river runoff distribution and high and low flows in Latvia, covering river basins within four hydrological districts which vary according to size and physiographical conditions. Mathematical statistical methods were applied in the analysis of river discharge data series for two study periods of 1951–2009 and 1881–2009. The present results confirm the basic statement concerning the Baltic countries that major significant changes in river runoff during the last two decades have occurred between spring (decrease) and winter (increase) seasons. Mostly insignificant changes in summer runoff and significant/insignificant changes in autumn runoff were found. Analysis shows that a statistically significant trend of increase in low flow for the cold period and a significant trend of decrease in the high discharge and coefficient d of uneven runoff distribution were detected. Changes in river hydrological regime are mainly caused by changes in large-scale atmospheric circulation processes following climate warming, which has taken place. Latvian river hydrography has therefore changed and become more similar to Western European rivers.

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