scholarly journals Time of concentration in torrential catchments in Serbia

2006 ◽  
pp. 7-21 ◽  
Author(s):  
Ratko Ristic
Keyword(s):  
Input Data ◽  
Lag Time ◽  
Physical Geography ◽  
Unit Hydrograph ◽  
Total Rainfall ◽  
Time Of Concentration ◽  
Rational Theory ◽  
Maximal Runoff ◽  
Maximal Discharge ◽  
Basic Input

Maximal discharge Qmax,p is the basic input data for the design of longitudinal and transversal objects in torrential beds. Calculation of maximal discharge Qmax, on unstudied catchments is performed by the following methods: combined procedure (the theory of synthetic unit hydrograph and SCS methodology for the separation of effective rainfall Pe from total rainfall Pb), rational theory and theory of maximal runoff intensity. Rational theory is a suitable method with representative time of concentration Tc. The time of concentration was determined on the basis of investigation on 93 control profiles, south from the Sava and the Danube. Time of concentration and dominant physical-geography characteristics of the catchments were the basis for deriving the equations with regional significance [Tc=f(A), Tc=f(L), Tc=f(L, Lc, Iu), Tc=f(L, Iu), Tc=f(L, Isr), Tc=f(L, Iu, Isr)]. The relation between time of concentration Tc and lag time tp was determined [Tc=f(tp)].

scholarly journals Lag time on torrential catchments in Serbia

2003 ◽  
pp. 51-65 ◽  
Author(s):  
Ratko Ristic
Keyword(s):  
Catchment Area ◽  
Lag Time ◽  
Physical Geography ◽  
Main Stream ◽  
Total Rainfall ◽  
River Bed ◽  
Average Slope ◽  
Unit Hydrographs ◽  
Maximal Discharge ◽  
Basic Input

Maximal discharge Qmax(p) is the basic input data for designing longitudinal and transversal objects in torrential beds. Calculation of maximal discharge Qmax, on unstudied catchments, is carrying out by usage the theory of synthetic unit hidrograph and SCS methodology for separation effective rain Pe by total rainfall Pb. One of the basic time characteristics of torrential floods was analyzed: lag time tp. Lag time tp was determined on the basis of processing of hydrographs and deriving representative unit hydrographs, on 93 control profiles. Dominant physical-geography characteristics were determined: magnitude of the catchment area A, length of the catchment area along the main stream L, the distance from the centroid of the catchment area to the outlet profile Lc, average slope of the river bed Iu, average slope of terrain on the catchment area Isr. Lag time and dominant physical-geography characteristics were the basis for deriving some equations with regional significance (tp=f(L, Lc, Iu); tp=f(L, Lc, Iu, Isr)). The relation between lag time tp and time of concentration Tc was determined (tp=f(Tc)).

scholarly journals Status of Molecular Opacities of Interest in the Modeling of a Proto-Solar Nebula

1974 ◽  
Vol 65 ◽  
pp. 13-20
Author(s):  
W. F. Huebner ◽  
L. W. Fullerton
Keyword(s):  
Optical Properties ◽  
Equation Of State ◽  
Volatile Compounds ◽  
Gaseous Phase ◽  
Input Data ◽  
Solar Nebula ◽  
Ionic Species ◽  
Constitutive Properties ◽  
Gas Medium ◽  
Basic Input

The report centers on general procedures applicable to the calculation of constitutive properties (equation of state and opacity) of media that serve as models for the solar nebula during planet formation and for the atmospheres of some planets. Specifically considered are the equilibrium compositions of a mixture of atoms, molecules, and their ionic species in the gaseous phase, condensation into grains with refractory cores and mantles of volatile compounds, and the ‘optical’ properties of the grain-gas medium. A summary of available and still needed basic (input) data and some currently available results are presented.

scholarly journals Uncertainty and Sensitivity Analysis of Void Reactivity Feedback for 3D BWR Assembly Model

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Andrius Slavickas ◽  
Raimondas Pabarčius ◽  
Aurimas Tonkūnas ◽  
Eugenijus Ušpuras
Keyword(s):  
Sensitivity Analysis ◽  
Cross Section ◽  
Input Data ◽  
Statistical Approach ◽  
Assembly Model ◽  
Uncertainty And Sensitivity Analysis ◽  
Geometrical Dimensions ◽  
Basic Input ◽  
Propagation Of Uncertainties ◽  
Selection Of

Uncertainty and sensitivity analysis of void reactivity feedback for 3D BWR fuel assembly model is presented in this paper. Uncertainties in basic input data, such as the selection of different cross section library, manufacturing uncertainties in material compositions, and geometrical dimensions, as well as operating data are considered. An extensive modelling of different input data realizations associated with their uncertainties was performed during sensitivity analysis. The propagation of uncertainties was analyzed using the statistical approach. The results revealed that important information on the code predictions can be obtained by analyzing and comparing the codes estimations and their associated uncertainties.

Fire Protection of High-Performance Concrete Using Protective Lining

2011 ◽  
Vol 82 ◽  
pp. 758-763
Author(s):  
Eike Wolfram Klingsch ◽  
Andrea Frangi ◽  
Mario Fontana
Keyword(s):  
High Performance ◽  
Input Data ◽  
High Performance Concrete ◽  
Fire Behavior ◽  
Explosive Spalling ◽  
Protective Lining ◽  
In Fire ◽  
Concrete Elements ◽  
Basic Input ◽  
Fire Design

The paper presents results of experimental and numerical analyses on the fire behavior of concrete elements protected by sprayed protective linings. Particular attention is given to high- (HPC) and ultrahigh performance concrete (UHPC), as HPC and UHPC tend to exhibit explosive spalling in fire due to low porosity. The results provide basic input data for the development of simplified rules for the fire design of concrete structures protected by sprayed protective linings.

scholarly journals Parameter Adjustment to Prevent the Overestimation of Peak Discharge in a Small Watershed

2021 ◽  
Vol 21 (6) ◽  
pp. 285-291
Author(s):  
JongChun Kim ◽  
Jongho Jeong
Keyword(s):  
Response Time ◽  
Peak Discharge ◽  
Small Watershed ◽  
Unit Hydrograph ◽  
Area Method ◽  
Time Of Concentration ◽  
Rainfall Duration ◽  
Reasonable Range ◽  
Specific Discharge ◽  
Basin Response

We revisit empirical methods to prevent the overestimation of peak discharge in a small watershed, in particular investigating the time-area method, which has not been considered in the overestimation problem of peak discharge. To avoid misapplying the same inlet time between the unit hydrograph and rational formula, distinct parameter adjustments for each method are proposed. We adopt the secondary basin response time for the unit hydrograph, rainfall duration for the rational formula, and time of concentration for the time-area method, as suitable parameters to adjust the estimation of peak discharge. In conclusion, adding 10 minutes to secondary basin response time, 20 minutes to rainfall duration, and 30 minutes to time of concentration, respectively, yields estimates within a reasonable range of specific discharge in a small watershed.

Flash flood simulation using unit hydrograph and hydrodynamic models (case study of Western Caucasus, Russia)

2020 ◽  
Author(s):  
Pelagiya Belyakova ◽  
Ekaterina Vasil'eva ◽  
Andrey Aleksyuk ◽  
Vitaly Belikov ◽  
Boris Gartsman ◽  
...  
Keyword(s):  
Shallow Water ◽  
Monitoring System ◽  
Input Data ◽  
Flash Flood ◽  
Rainfall Runoff ◽  
Western Caucasus ◽  
Unit Hydrograph ◽  
Runoff Simulation ◽  
Flood Simulation ◽  
Flood Monitoring

<p>In the Russian part of Western Caucasus heavy rainfall episodes frequently occur, leading to flash floods that often cause fatalities and severe damage. As soon as climate change is expected to increase the risk of flash floods it is necessary to improve flood forecasting and flood risk mapping as well as other precautionary measures. For this scope the better knowledge of catchment response on heavy precipitation is needed using rainfall-runoff simulation and further hydrodynamic modelling of inundation of urbanized areas.</p><p>There is a number of models used for flash flood simulation. In this study we used an available unit hydrograph model KW-GIUH [1] and a hydrodynamic model STREAM 2D CUDA [2]. KW-GIUH model only schematically describes overland flow over the catchment, nonlinear character of response is introduced via kinematic-wave approximation of the travel time. STREAM 2D CUDA is based on numerical solution of shallow water equations in a two-dimensional formulation according to the original algorithm using the exact solution of the Riemann problem [2], due to which the calculation is performed for the entire catchment without special allocation of the channel network. Models were tested on several flash flood events on the river Adagum (6-7 July 2012, catastrophic flood in the Krymsk town) and the Zapadny Dagomys river (25 June 2015, 24-25 October 2018, Sochi).</p><p>Comparison of simulation results was done as the same input data set was used. Input data included DEM HydroSHEDS, measured hourly precipitation and runoff volumes observed on gauges and estimated after high-water marks. Also 10-min water levels from a regional automated flood monitoring system of the Krasnodar Territory were applied. Simulated runoff volumes and peak timing were analyzed. For the Zapadny Dagomys river a forecasting calculation was done using precipitation forecast from COSMO-Ru. For the Adagum river STREAM 2D CUDA allowed to conduct an experiment to assess possible effect from potential reservoir-traps in the tributaries. The results of the rainfall-runoff simulation by the KW-GIUH model can be used as inflow to the boundary of the area for hydrodynamic modeling using STREAM 2D CUDA, also for operational use. Scenario calculations with changing hydraulic conditions at the catchment can be simulated using the STREAM 2D CUDA model itself.</p><p>The flood simulation was supported by the Russian Science Foundation under grant №17-77-30006. Data processing from an automated flood monitoring system in the Krasnodar Territory is funded by Russian Foundation for Basic Research and the Krasnodar Territory, grant № 19-45-233007.</p><p>References:</p><ol><li>Lee K.T., Cheng N.K., Gartsman B.I., Bugayets A.N. (2009): A current version of the model of a unit hydrograph and its use in Taiwan and Russia, Geography and Natural Resources, Volume 30, issue 1, pp. 79–85. https://doi.org/10.1016/j.gnr.2009.03.015</li> <li>Aleksyuk A.I., Belikov V.V. (2017): Simulation of shallow water flows with shoaling areas and bottom discontinuities, Computational Mathematics and Mathematical Physics, Volume 57, issue 2, pp. 318–339. https://doi.org/10.1134/S0965542517020026</li> </ol>

scholarly journals Infiltration Losses Calculated for the Flash Flood in the Upper Catchment of Geru River, Galaţi County, Romania

2016 ◽  
Vol 10 (2) ◽  
pp. 219-234
Author(s):  
Isabela Balan ◽  
Loredana Crenganiş ◽  
Flaviana Corduneanu ◽  
Claudiu Pricop ◽  
Loredana Andreea Popoiu
Keyword(s):  
Mathematical Modelling ◽  
Input Data ◽  
Flash Flood ◽  
Rainfall Runoff ◽  
Unit Hydrograph ◽  
Phase Errors ◽  
Loss Method ◽  
Hydrometric Station ◽  
The Village ◽  
Amplitude And Phase Errors

Abstract MIKE software created by Danish Institute of Hydraulics can be used to perform mathematical modelling of rainfall-runoff process on the hillslopes, resulting in a runoff hydrograph in the closing section of a catchment. The software includes a unitary hydrograph method - UHM in the hydrological module Rainfall - Runoff. Excess rainfall is routed to the river and transited through unit hydrograph method. The model divides the flood generating precipitation in excess rainfall (net rainfall) and losses (infiltration). This paper analyzes data from the flash flood that occurred between the 11th and 13th of September 2013 in the upper catchment of the river Geru. The catchment chosen for study, is controlled by the hydrometric station located in the village Cudalbi. Simulations of this flash flood were performed with MIKE by DHI –UHM software, alternatively using as input data the precipitations recorded by AHSS (Automated Hydrological Sensor Station) Cudalbi and radar precipitations generated by ROFFG (Romanian Flash Flood Guidance) software system in ArcGIS module for determining the areas affected by flash floods. The Unitary Hydrograph Method - UHM from the hydrological module Rainfall – Runoff calculates excess rainfall and determines infiltration losses by four methods. For each set of input data, the four methods for calculating infiltration losses were subsequently used. The comparison between the results highlights that the amplitude and phase errors for the maximum discharge are smaller when the model uses for simulation radar precipitations as input data, and calculates infiltration losses with the Proportional Loss method. This method reproduces with a better accuracy the peaks of the discharge hydrograph. The model can be used in the future to forecast a discharge hydrograph based on estimated radar precipitations in the catchment

scholarly journals A Combination between Synthetic Unit Hydrograph (SCS) and Rational Method in a similar Conditions Water Shed

2021 ◽  
Vol 9 (3) ◽  
Author(s):  
Mona Fathi ◽  
Neveen B. Abelmageed ◽  
M. Hassan
Keyword(s):  
Rational Method ◽  
Rainfall Data ◽  
Return Periods ◽  
Unit Hydrograph ◽  
Engineering Applications ◽  
Watershed Characteristics ◽  
Time Of Concentration ◽  
Excess Water ◽  
The Difference ◽  
Peak Runoff

Studying watershed characteristics and choosing the most applicable methods to determine the amount of access rainfall that ran off is very important in many engineering applications, especially hydrology applications. That is to know the more suitable methods for protection against floods and to maximize benefits from the excess water. This study aims to establish a relation between the rational method and the SCS method. A subbasin in Wadi Dahab in Sinai, Egypt is investigated as a study area. To achieve the study aims, HEC-WMS software is chosen, which can analyze a watershed by using DEM and delineating basin. It calculates also important watershed parameters like area, runoff distances, and slope. The rainfall data is compiled and arranged. A statical analysis is executed to obtain the IDF curves. Hyfran-plus software is employed to locate the maximum depths for different return periods. Various values for the time of concentration are studied. It is concluded that the difference between the rational and SCS methods is great for the time of concentration till 2 hours, then it decreases obviously from 2 till 6 hours. Also, it is concluded that the difference between the two methods is bigger for the small return periods of 2 and 5 years for all values of the time of concentration. Employing the obtained equations, the peak runoff for one of the two methods (the rational and SCS methods) can be calculated knowing the time of concentration and the peak runoff for the second method.  

Estimation of Time of Concentration for Maryland Streams

2000 ◽  
Vol 1720 (1) ◽  
pp. 95-99 ◽  
Author(s):  
Wilbert O. Thomas ◽  
Michele C. Monde ◽  
Stanley R. Davis
Keyword(s):  
Lag Time ◽  
Channel Length ◽  
Urban Watersheds ◽  
Regression Equations ◽  
Hydrologic Models ◽  
Watershed Characteristics ◽  
Time Of Concentration ◽  
Station Data ◽  
Rural And Urban ◽  
Gauging Station

The time of concentration (TC) is an important input to most hydrologic models and is usually estimated by travel-time computations or by using rainfall-runoff data. Average TCs were determined for 78 rural and urban watersheds in Maryland and related to watershed characteristics using regression analysis. The regression equation is based on the channel length and slope; the percentage of the watershed covered with forests, lakes, and ponds; and the percentage of the watershed with impervious areas. The equation is applicable for estimating TCs for rural and urban watersheds in Maryland with watershed characteristics similar to the gauging station data. TC values computed at Maryland gauging stations were compared with estimates from an equation developed by Kirpich and the Soil Conservation Service (SCS) lag equation, and with basin lag times determined by the U.S. Geological Survey (USGS). The average TC values computed in this analysis were about 5 percent higher than the basin lag-time estimates, which is consistent with the USGS’s definition of lag time. TC estimates from the Kirpich or SCS equations were consistently lower than the values computed from gauging station data. The tendency to underestimate TCs is a major reason why hydrologic models often provide conservative estimates of design discharges compared with regional regression equations and gauging station data.

Relevance of the H2U model to predict the discharge of a catchment

1997 ◽  
Vol 36 (5) ◽  
pp. 169-175 ◽  
Author(s):  
J. Duchesne ◽  
C. Cudennec ◽  
V. Corbierre
Keyword(s):  
Production Function ◽  
Deterministic Model ◽  
Effective Rainfall ◽  
Unit Hydrograph ◽  
Natural Conditions ◽  
Total Rainfall ◽  
Surface Area Ratio ◽  
The Mean ◽  
Water Speed ◽  
Very High

The new deterministic model H2U (from French “Hydrogramme unitaire universel”) is validated for two Mediterranean catchments, both in natural conditions, in the south of France and in the very anthropic catchment of Paris-Orly airport. It starts from a description of the drainage network by means of a density function of the hydraulic lengths. Through the mean water speed in the channels, this function is proved to be the unit hydrograph, or transfer function of the catchment. Moreover, in some cases, the production function can be directly known, for instance when the rain intensity is very high, or, if rain intensities are rather low, when the impervious surface area ratio is known and can be considered as the effective rainfall/total rainfall ratio. Then, the H2U model can give directly a good simulated curve of discharge, without any calibration except for the estimation of the mean water speed. The model can probably give good simulations in any situation provided that the production function has been evaluated. Even better, it can be used as the known kernel function in order to obtain the effective rainfall, i.e. the production function, by deconvolution of the actual hydrograph.

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