Implications of Distinct Methodological Interpretations and Runoff Coefficient Usage for Rational Method Predictions

Author(s):  
Dana Ariel Lapides ◽  
Anneliese Sytsma ◽  
Sally Thompson
Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1669 ◽  
Author(s):  
Nam Kim ◽  
Mun-Ju Shin

Hourly flood flow estimation for gauged and ungauged catchments is a prerequisite for planning and water management. Various methods have been applied in a multitude of studies to calculate the peak flow for ungauged catchments. However, it is not simple for engineers to use the existing methods in practical applications. An easier method is suggested for this purpose in this study. The authors estimated the relationship between the runoff coefficient, intensity of rainfall, and curve number, and then utilized the relationship to calculated the peak flow using the rational method for ungauged catchments. Rainfall and flood time series for ungauged study catchments were generated by a simple data generation method and a distributed rainfall–runoff model. Results showed that the runoff coefficients simulated using the estimated relationship reasonably agree with the runoff coefficients in the studied ungauged catchments. In addition, the peak flow simulated using the rational method and the relationship highly agree with the peak flow in the ungauged catchments. Therefore, the peak flow in ungauged catchments can be easily calculated by this method, which is more pragmatic for engineers.


2017 ◽  
Vol 13 (1) ◽  
pp. 1
Author(s):  
Elvi Roza Syofyan ◽  
Amrizal Saidi ◽  
Bambang Istijono ◽  
Revalin Herdianto

The purpose of the study is to look at changes in land use and hydrograph models of  Danau Limau Manis  Sub-watershed using  data 2011 until 2015.The results shows the change of  land use of Batang Kuranji Watershed,  Sub DAS Danau Limau Manis can decreased 3.03%  from 2011 to 2015. It due to the opening of new land. While shrub rose rose 0360%, because was due of changes of forests that have not done processing. For an others using of the land  the number increase 3.40%. It due to changes of forests and shrubs into failure land.. As the runoff coefficient (C) does not occur any significant change that is from 0.405 into 0.408. Peak discharge calculated by the Nakayasu method 128.02 m3 / dt, was greater by Rational method of 127,52  m3 / dt is caused no difference in the approach used.


1999 ◽  
Vol 30 (2) ◽  
pp. 129-146 ◽  
Author(s):  
N. R. Nawaz ◽  
A. J. Adeloye ◽  
M. Montaseri

In this paper, we report on the results of an investigation into the impacts of climate change on the storage-yield relationships for two multiple-reservoir systems, one in England and the other in Iran. The impact study uses established protocol and obtains perturbed monthly inflow series using a simple runoff coefficient approach which accounts for non-evaporative losses in the catchment, and a number of recently published GCM-based scenarios. The multi-reservoir analysis is based on the sequent-peak algorithm which has been modified to analyse multiple reservoirs and to accommodate explicitly performance norms and reservoir surface fluxes, i.e. evaporation and rainfall. As a consequence, it was also possible to assess the effect of including reservoir surface fluxes on the storage-yield functions. The results showed that, under baseline conditions, consideration of net evaporation will require lower storages for the English system and higher storages for the Iranian system. However, with perturbed hydroclimatology different impacts were obtained depending on the systems' yield and reliability. Possible explanations are offered for the observed behaviours.


1994 ◽  
Vol 29 (1-2) ◽  
pp. 303-310 ◽  
Author(s):  
Kazuyuki Higuchi ◽  
Masahiro Maeda ◽  
Yasuyuki Shintani

The Tokyo Metropolitan Government has planned future flood control for a rainfall intensity of 100 mm/hr, which corresponds to a return period of 70 years, and a runoff coefficient of 0.8. Considering that the realization of this plan requires a long construction period and high construction costs, the decision was made to proceed by stages. In the first stage, the improvement of the facilities will be based on a rainfall intensity of 75 mm/hr (presently 50 mm/hr), corresponding to a return period of 17 years, and a runoff coefficient of 0.8. In the next stage the facilities will be improved to accommodate a rainfall intensity of 100 mm/hr. In the Nakano and Suginami regions, which suffer frequently from flooding, the plan of improvement based on a rainfall intensity of 75 mm/hr is being implemented before other areas. This facility will be used as a storage sewer for the time being. The Wada-Yayoi Trunk Sewer, as a project of this plan, will have a diameter of 8 m and a 50 m earth cover. This trunk sewer will be constructed considering several constraints. To resolve these problems, hydraulic experiments as well as an inventory study have been carried out. A large drop shaft for the trunk sewer is under construction.


Author(s):  
Paul Brooker ◽  
Margaret Hayward

The Conclusion points out that the preceding seven chapters’ examples and case studies have revealed some expected, and some unexpected conclusions. The six main cases revealed some expected uniformity in the leaders’ selection of rational methods. There was less uniformity, however, in the choice of the methods they emphasized, whether due to their personal preferences or to the circumstances they were facing. Two unexpected findings were the addition of a seventh appropriate rational method—learning—and the prevalence of dual-leadership teams. The conclusion goes on to suggest that this book’s theory and approach should be applied to versions of military leadership and to the political leadership of contemporary democracies.


Author(s):  
Cristian Epifanio Toledo ◽  
João Carlos Mohn Nogueira ◽  
Alexandre De Amorim Camargo

The objective of this work was to propose and evaluate a model to estimate transit water losses and surface runoff in a Brazilian semi-arid basin, fundamental components in the hydrological studies of the region, such as in the verification of hydrological connectivity. The study area was the Orós Reservoir Basin, located in the state of Ceará. The modeling of transit water loss and surface runoff were developed based on the work of Araújo and Ribeiro (1996) and Peter et al. (2014). In the proposed model, the parameter of loss in transit (k) was estimated at 0.027 km-1 for a section of the river basin, and when simulated for other stretches it provided good flow results at the end of the stretch, obtaining an NSE of 82%. The value of the runoff coefficient was estimated at 3% and when evaluating a spatial variation of this coefficient in the basin, the values varied from 2% to 12%, and the use of specialized runoff coefficient (RC) values promoted a higher NSE in the discharge simulation in the basin. It is concluded that the proposed model to estimate transit water losses and surface runoff demonstrated a high efficiency in the simulation of hydrological processes. The basin of Orós reservoir presented a high variability of the coefficient of surface runoff, justifying the need for a greater spatiality of this coefficient in heterogeneous environments.


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