Proving WATFLOOD: modelling the nonlinearities of hydrologic response to storm intensities

2001 ◽  
Vol 28 (5) ◽  
pp. 837-855 ◽  
Author(s):  
A J Cranmer ◽  
N Kouwen ◽  
S F Mousavi

This paper examines the effects of modelling the nonlinearities of hydrologic response to various storm intensities. Radar rainfall data, remotely sensed land use and land cover data, measured streamflows, and meteorological data were incorporated into the distributed flood forecasting model WATFLOOD to synthesize runoff hydrographs for three significant warm weather rainfall events occurring in 1995. The watershed selected for study was the 288 km2 Duffins Creek drainage basin in southern Ontario. The effects of scaling radar rainfall amounts to match regional storm intensities on the synthesized streamflow hydrographs were examined. Computations and analysis were performed in agreement with widely accepted hydrologic principles and assumptions. The observed and synthesized hydrographs were compared using the unit hydrograph method. The observed and composite unit hydrographs matched extremely well in terms of shape, timing, and peak flow magnitude. These results indicated that WATFLOOD is capable of accurately modelling the nonlinear rainfall–runoff processes for increasing rainfall intensities with respect to peak flow, basin lag, and time to peak flow. However, the arbitrariness of assessing the effective rainfall and base-flow separation for the unit hydrograph method can lead to uncertainties in computing peak flow magnitudes. The grid element size and number and the drainage areas above streamflow gauges are of critical importance to the accuracy of the model.Key words: hydrology, watershed model, flood forecasting, hydrological modelling, model validation, unit hydrograph, nonlinear response.

1985 ◽  
Vol 16 (1) ◽  
pp. 1-10 ◽  
Author(s):  
V. P. Singh ◽  
C. Corradini ◽  
F. Melone

The geomorphological instantaneous unit hydrograph (IUH) proposed by Gupta et al. (1980) was compared with the IUH derived by commonly used time-area and Nash methods. This comparison was performed by analyzing the effective rainfall-direct runoff relationship for four large basins in Central Italy ranging in area from 934 to 4,147 km2. The Nash method was found to be the most accurate of the three methods. The geomorphological method, with only one parameter estimated in advance from the observed data, was found to be little less accurate than the Nash method which has two parameters determined from observations. Furthermore, if the geomorphological and Nash methods employed the same information represented by basin lag, then they produced similar accuracy provided the other Nash parameter, expressed by the product of peak flow and time to peak, was empirically assessed within a wide range of values. It was concluded that it was more appropriate to use the geomorphological method for ungaged basins and the Nash method for gaged basins.


2019 ◽  
Vol 76 ◽  
pp. 02007
Author(s):  
Mega Yulisetya Widasmara ◽  
Pramono Hadi ◽  
Nugroho Christanto

Water, a vital natural resource for a human being, could bring negative effects such as flood and landslides. The best way to show the hydrological process is called “model”. One of them is Modified Rational Method (MRM). There are several types of MRM base on its equation modification. Hydrological mass balance or kinematic wave in order to route the flow. With this model modification, the output of the model is not only peak discharge but also unit hydrograph. Model modification was done in the calculation of peak discharges by assigning the C value (coefficient runoff), A value (area) and land characteristic (soil texture, Manning roughness coefficient, and saturation coefficient in the pixel basis. PCRaster software allows us to perform discharge calculation on each pixel. Flow accumulation by using kinematic wave was done to get the unit hydrograph. Three (3) flood events were used to run the model validation, i.e. January 21, January 22, and February 10, 2016. Each event has different rainfall characteristics. The result of this model was DRO hydrograph. Based on the baseflow separation of the observed hydrograph as well as the hydrograph from the model, we found that the flow through the outlet during discharge recession is the base flow. The accuracy value is quite good, i.e. 10–30 %. The result of the model shows a different response between direct runoff and base flow, while time to peak was faster than the recession time.


2017 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Agung Budi Supangat

The wide scale development of Eucalyptus pellita F. Muell plantation in Riau Province applying the clear cutting silvicultural system on fast-growing tree species allegedly have an impact on the changing of watershed hydrological functions. The aim of this study was to determine the changes in the characteristics of after logging stream flow hydrograph of E. pellita forest stand. The research was carried out in E. pellita plantations in Perawang, Riau Province using 4.62 ha of micro-catchment as an observation unit. The method used is the analysis of hydrograph units on chosen data of flood hydrograph. The research concludes that clear-cutting system has led to increasing the peak flow discharge from an average of 0.226 m3.s-1 to be 0.322 m3.s-1, shortening the time base of hydrograph from an average of 143 minutes to be 90 minutes, shortening the time to peak flow from an average of 80 minutes to be 40 minutes, as well as declining the base flow from an average of 0.0056 m3.s-1 to be 0.0032 m3.s-1.


Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1456
Author(s):  
Kee-Won Seong ◽  
Jang Hyun Sung

An oscillatory S-curve causes unexpected fluctuations in a unit hydrograph (UH) of desired duration or an instantaneous UH (IUH) that may affect the constraints for hydrologic stability. On the other hand, the Savitzky–Golay smoothing and differentiation filter (SG filter) is a digital filter known to smooth data without distorting the signal tendency. The present study proposes a method based on the SG filter to cope with oscillatory S-curves. Compared to previous conventional methods, the application of the SG filter to an S-curve was shown to drastically reduce the oscillation problems on the UH and IUH. In this method, the SG filter parameters are selected to give the minimum influence on smoothing and differentiation. Based on runoff reproduction results and performance criteria, it appears that the SG filter performed both smoothing and differentiation without the remarkable variation of hydrograph properties such as peak or time-to peak. The IUH, UH, and S-curve were estimated using storm data from two watersheds. The reproduced runoffs showed high levels of model performance criteria. In addition, the analyses of two other watersheds revealed that small watershed areas may experience scale problems. The proposed method is believed to be valuable when error-prone data are involved in analyzing the linear rainfall–runoff relationship.


2014 ◽  
Vol 23 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Izabela Pietrusiewicz ◽  
Agnieszka Cupak ◽  
Andrzej Wałęga ◽  
Bogusław Michalec

Abstract The paper presents the results of using two models: a conceptual model of Wackermann and a NRCS-UH synthetic unit hydrograph, for flow calculation in uncontrolled catchment of the Słonka, Poland. These models were chosen because of simplicity of models’ parameters evaluation, what is important from engineering calculation point of view. Flows with the probability of exceed amounting to 0.5%, 1%, 2%, 5%, 10%, 20%, and 50% and for different levels of the catchment moisture were evaluated. The flood waves generated in the Wackermann model were characterized by a short duration (over 2 hours), shorter concentration time (about 1 hour), and by about 70% higher peak flow values than those generated using the NRCS-UH method. A common feature of both methods were higher values of peak flows for the third level of the catchment moisture, as compared to the second level. It is also worth noticing that in both methods no flood wave was generated for the probabilities of 10, 20 and 50% and for the second level of the catchment moisture. It was assumed that hydrographs made with use Wackermann model better describe flood wave in mountain river, which Słonka is.


2009 ◽  
Vol 6 (1) ◽  
pp. 319-371
Author(s):  
E. R. Vivoni ◽  
C. A. Aragón ◽  
L. Malczynski ◽  
V. C. Tidwell

Abstract. Hydrologic processes in the semiarid regions of the southwest United States are considered to be highly susceptible to variations in temperature and precipitation characteristics due to the effects of climate change. Relatively little is known on the potential impacts of climate change on the basin hydrologic response, namely streamflow, evapotranspiration and recharge, in the region. In this study, we present the development and application of a continuous, semi-distributed watershed model for climate change studies in semiarid basins of the southwest US. Our objective is to capture hydrologic processes in large watersheds, while accounting for the spatial and temporal variations of climate forcing and basin properties in a simple fashion. We apply the model to the Río Salado basin in central New Mexico since it exhibits both a winter and summer precipitation regime and has a historical streamflow record for model testing purposes. Subsequently, we utilize a sequence of climate change scenarios that capture observed trends for winter and summer precipitation, as well as their interaction with higher temperatures, to perform long-term ensemble simulations of the basin hydrologic response. Results of the modeling exercise indicate that precipitation uncertainty is amplified in the hydrologic response, in particular for processes that depend on a soil saturation threshold. We obtained substantially different hydrologic sensitivities for winter and summer precipitation ensembles, indicating a greater sensitivity to more intense summer storms as compared to more frequent winter events. In addition, the impact of changes in precipitation characteristics overwhelmed the effects of increased temperature in the study basin. Nevertheless, combined trends in precipitation and temperature yield a more sensitive hydrologic response throughout the year.


Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1263 ◽  
Author(s):  
Dachen Li ◽  
Simin Qu ◽  
Peng Shi ◽  
Xueqiu Chen ◽  
Feng Xue ◽  
...  

To date, floods have become one of the most severe natural disasters on Earth. Flood forecasting with hydrological models is an important non-engineering measure for flood control and disaster reduction. The Xin’anjiang (XAJ) model is the most widely used hydrological model in China for flood forecasting, while the Soil and Water Assessment Tool (SWAT) model is widely applied for daily and monthly simulation and has shown its potential for flood simulation. The objective of this paper is to evaluate the performance of the SWAT model in simulating floods at a sub-daily time-scale in a slightly larger basin and compare that with the XAJ model. Taking Qilijie Basin (southeast of China) as a study area, this paper developed the XAJ model and SWAT model at a sub-daily time-scale. The results showed that the XAJ model had a better performance than the sub-daily SWAT model regarding relative runoff error (RRE) but the SWAT model performed well according to relative peak discharge error (RPE) and error of occurrence time of peak flow (PTE). The SWAT model performed unsatisfactorily in simulating low flows due to the daily calculation of base flow but behaved quite well in simulating high flows. We also evaluated the effect of spatial scale on the SWAT model. The results showed that the SWAT model had a good applicability at different spatial scales. In conclusion, the sub-daily SWAT model is a promising tool for flood simulation though more improvements remain to be studied further.


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