COMPARISON OF DIMENSIONLESS UNIT HYDROGRAPHS IN THAILAND AND TAIWAN

1971 ◽  
Vol 2 (1) ◽  
pp. 23-46 ◽  
Author(s):  
EDMUND F. SCHULZ ◽  
SUBIN PINKAYAN ◽  
CHUMPORN KOMSARTRA
Keyword(s):  
Base Length ◽  
Unit Hydrograph ◽  
Time To Peak ◽  
Dimensionless Unit ◽  
Instantaneous Unit Hydrograph ◽  
Subsurface Runoff ◽  
Tropical Watersheds ◽  
Unit Hydrographs ◽  
Similar Unit ◽  
Two Parameter

The characteristics of dimensionless unit hydrographs were derived from floods from watersheds smaller than 1000 square kilometers located in Thailand. The dimensionless unit hydrographs were expressed as ratios of q/qq as a function of t/tp. These dimensionless unit hydrographs were compared with similar unit hydrographs derived from floods on Taiwan and with the unit hydrographs derived from a mathematical model developed from the two parameter gamma function developed from the theory of the instantaneous unit hydrograph. It was found that the unit hydrographs derived from the Thai watersheds had much longer base length and much longer time to peak than similar unit hydrographs derived from floods on Taiwan. This increase in length of response time is attributed to a larger component of subsurface runoff believed to be present in the floods from tropical watersheds.

scholarly journals A measure of watershed nonlinearity: interpreting a variable instantaneous unit hydrograph model on two vastly different sized – watersheds

2005 ◽  
Vol 2 (5) ◽  
pp. 2111-2151
Author(s):  
J. Y. Ding
Keyword(s):  
Shape Factor ◽  
Overland Flow ◽  
Convolution Integral ◽  
Unit Hydrograph ◽  
N Value ◽  
Time To Peak ◽  
The Us ◽  
Instantaneous Unit Hydrograph ◽  
Unit Hydrographs ◽  
A Minor

Abstract. This paper reviews the use of an input-dependent kernel in a linear convolution integral as a quasi-nonlinear approach to unify nonlinear overland flow, channel routing and catchment runoff processes. The conceptual model of a variable kernel or instantaneous unit hydrograph (IUH) is characterized by a nonlinear storage-discharge relation, q=cNsN where the storage exponent N is an index or degree of watershed nonlinearity. When the causative rainfall excess intensity of a unit hydrograph is known, parameters N and c can be determined directly from its shape factor, the product of the unit peak ordinate and the time to peak. The model is calibrated by the shape factor and verified by convolution integral on two watersheds of vastly different sizes, each having a family of four or five unit hydrographs, data of which were published by Childs in 1958 for the Naugatuck River and by Minshall in 1960 for the Edwardsville catchment. For an 11-hectare catchment near Edwardsville in southern Illinois, the US, four moderate storms show an average N value of 1.79, which is 7% higher than the theoretical value of 1.67 by Manning friction law, while the heaviest storm, which is three to six times larger than the next two events in terms of the peak discharge and runoff volume, follows the Chezy law of 1.5. At the other end of scale, for the Naugatuck River at Thomaston in Connecticut, the US, having a drainage area of 186.2 km2, the average N value of 2.28 varies from 1.92 for a minor flood to 2.68 for a hurricane-induced flood, all of which lie between the theoretical value of 1.67 for turbulent overland flow and that of 3.0 for laminar overland flow. Short examples and a spreadsheet template are given to illustrate key steps in generating the direct runoff hydrograph by convolution integral with the 2-parameter variable IUH model.

scholarly journals A Comparison of Some Methods of Deriving the Instantaneous Unit Hydrograph

1985 ◽  
Vol 16 (1) ◽  
pp. 1-10 ◽  
Author(s):  
V. P. Singh ◽  
C. Corradini ◽  
F. Melone
Keyword(s):  
Peak Flow ◽  
Central Italy ◽  
Effective Rainfall ◽  
Unit Hydrograph ◽  
Time To Peak ◽  
Wide Range ◽  
Instantaneous Unit Hydrograph ◽  
Similar Accuracy ◽  
Two Parameters ◽  
Range Of Values

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.

scholarly journals The Role of Topography on the Shape of Unit Hydrographs in Small and Medium Sized Watersheds through a Physical Model

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2270
Author(s):  
Alicia A. Del Rio ◽  
Aldo I. Ramirez ◽  
Mauricio A. Sanchez
Keyword(s):  
Fuzzy Logic ◽  
Polynomial Regression ◽  
Synthetic Methods ◽  
Main Stream ◽  
Unit Hydrograph ◽  
Watershed Area ◽  
Time To Peak ◽  
Logic Models ◽  
Empirical Relations ◽  
Unit Hydrographs

This study intends to establish the main relations between topographic characteristics of the watershed and the main parameters of the unit hydrograph measured at the outlet. It looks to remove the subjectivity found in traditional synthetic methods and the trial and error setting of the main parameters of the hydrograph. The work was developed through physical experimentation of the rainfall-runoff process using the observed information of different watersheds of Chiapas, Mexico, as the reference. The experiments were carried out on a state-of-the-art semi-automatic runoff simulator, which was designed and built specifically for this study. Polynomial regression and fuzzy logic models were obtained to confirm the hypothesis of hydrological parameters being obtained from topographic data only by assuming uniform precipitation. Empirical relations were found for the peak flow, time to peak, base time and volume of the unit hydrograph and the watershed area, the main stream average slope, and the length of the stream of highest order. The main finding is that a unit hydrograph can be described based only on the watershed area when fuzzy logic models are applied.

scholarly journals The geomorphological unit hydrograph – a critical review

1998 ◽  
Vol 2 (1) ◽  
pp. 1-8 ◽  
Author(s):  
A. Y. Shamseldin ◽  
J. E. Nash
Keyword(s):  
Critical Review ◽  
Drainage Network ◽  
Unit Hydrograph ◽  
Channel Network ◽  
Geomorphological Unit ◽  
Catchment Characteristics ◽  
Scale Factors ◽  
Instantaneous Unit Hydrograph ◽  
Plausible Hypothesis ◽  
Two Parameter

Abstract. The theory of the geomorphological unit hydrograph (GUH) is examined critically and it is shown that the inherent assumption that the operation of the drainage network may be modelled by a corresponding network of linear reservoirs so restricts the instantaneous unit hydrograph (IUH) shape that the effects of further restrictions, reflecting the constraints imposed by the geomorphological laws of the channel network, cannot easily be identified. Without such identification, the geomorphological unit hydrograph theory is untestable and must remain only a plausible hypothesis providing an indication of a two-parameter IUH whose shape and scale factors must still be related empirically to appropriate catchment characteristics.

Regionalization of rainfall–runoff processes in rice agriculture dominated watersheds

2006 ◽  
Vol 53 (10) ◽  
pp. 131-139 ◽  
Author(s):  
N.V. Rajyalakshmi ◽  
S. Dutta
Keyword(s):  
Rice Field ◽  
Storm Event ◽  
Rainfall Runoff ◽  
Unit Hydrograph ◽  
Stream Network ◽  
Rice Agriculture ◽  
Watershed Response ◽  
Instantaneous Unit Hydrograph ◽  
Daily Water ◽  
Unit Hydrographs

An approach for computing the instantaneous unit hydrograph of rice agriculture dominated watesheds is proposed using the topology and hydraulic charcterstics of its stream network and the hydrologic behaviour of the rice agriculture area. The effect of rice agriculture on the watershed response is considered as partial sink areas. The sink factor, a time-variant weight factor for a particular storm event, is computed from the daily water balanace equation of the rice field. The critcal features of the simulated instantaneous unit hydrographs in three gauged watersheds located in the river Mahanadi, India were then compared with that of the observed 24-hr unit hydrograph. The comparison shows a significant correlation between the two results.

Rainfall Runoff Hydrograph Prediction Using Dynamic Wave Based Instantaneous Unit Hydrograph

2020 ◽  
Author(s):  
Minyeob Jeong ◽  
Jongho Kim ◽  
Dae-Hong Kim
Keyword(s):  
Rainfall Intensity ◽  
Wave Model ◽  
Test Results ◽  
Rainfall Runoff ◽  
Unit Hydrograph ◽  
Time To Peak ◽  
Instantaneous Unit Hydrograph ◽  
Runoff Hydrographs ◽  
Dynamic Wave ◽  
Peak Value

<p>A method to predict runoff based on the instantaneous unit hydrograph and dynamic wave approximation is proposed. The method is capable of generating IUH of a watershed without the need of observed rainfall and runoff data, and only topography and surface roughness of a watershed are needed. IUHs were generated using a dynamic wave model and S-hydrograph method, and IUH generated was a function of both watershed and rainfall properties. The ordinate of IUH depends on the rainfall intensities, and the peak value of IUH was proportional to the rainfall intensity while the time to peak of the IUH was inversely proportional to the rainfall intensity.  Corresponding IUHs for different rainfall intensities were used to generate runoff hydrographs. Since the IUH is generated using a dynamic wave model, it can be a tool to physically simulate the rainfall-runoff processes. Also, nonlinear rainfall-runoff relationship can be taken into account by expressing IUH as a function of rainfall excess intensity. Several test results in ideal basins and in a real watershed show that the proposed method has a good capability in predicting runoff, while several limitations remain.</p><p>Keywords: rainfall-runoff, instantaneous unit hydrograph, dynamic wave model</p>

Development of geomorphological instantaneous unit hydrograph (GIUH) model for a new un-gauged watershed

2017 ◽  
Vol 2 (01) ◽  
pp. 54-59
Author(s):  
Jeetendra Kumar ◽  
R. Suresh ◽  
Safi Hassan
Keyword(s):  
Peak Discharge ◽  
Prediction Errors ◽  
Effective Rainfall ◽  
Storm Events ◽  
Unit Hydrograph ◽  
Time To Peak ◽  
Initial Stage ◽  
Damodar Valley ◽  
Geomorphological Instantaneous Unit Hydrograph ◽  
Instantaneous Unit Hydrograph

A geomorphological instantaneous unit hydrograph (GIUH) model was developed for a watershed of Damodar valley corporation, Hazaribagh, using Nash (1959) and Itrube (1982) methods to compute peak discharge (qpeak) and time to peak (tpeak). The model was calibrated and validated for five storm events, i.e. June 24-25 (1992), October 12-13 (1993), November 2-3 (1993), June 28 (1994) and August 6 (1996) by comparing their ordinates with the ordinates of instantaneous unit hydrograph (IUH). The GIUH was tested with absolute prediction errors (APE) of the ordinate of peak discharge. On comparison, it was found that, most of the GIUH models overestimated the runoff at initial stage, while underestimated at the latter stage in comparison to the IUHs, which was mainly due to consideration of const ant value of Ф-index, for computation of effective rainfall. The absolute prediction errors (APE) were computed to be 5.97, 18.09, 23.32, 9.64 and 7.52% of the ordinates of peak discharge for the storm events of June 24-25 (1992), October 12-13 (1993), November 2-3 (1993), June 28 (1994) and August 6 (1996) respectively.

Effects of agricultural drainage on streamflow in the Middle Thames River, Ontario, 1949–1980

1985 ◽  
Vol 12 (4) ◽  
pp. 875-885 ◽  
Author(s):  
Sergio E. Serrano ◽  
Hugh R. Whiteley ◽  
Ross W. Irwin
Keyword(s):  
Seasonal Distribution ◽  
Agricultural Drainage ◽  
Unit Hydrograph ◽  
Time To Peak ◽  
Storm Flow ◽  
Annual Total ◽  
Subsurface Runoff ◽  
Overland Runoff ◽  
Thames River ◽  
Volumetric Response

The effects of surface and subsurface agricultural drainage on streamflow in the Middle Thames River have been studied through the analysis of changes in the volumetric response, changes in the seasonal distribution of streamflow volumes, and changes in the time distribution of runoff response of the Middle Thames in the period 1949–1980.The results indicated that only small changes in streamflow behaviour occurred in the Middle Thames for the period studied. There is evidence of a reduction of less than 25% in the time-to-peak of storm hydrographs on the watershed, but with little change in peak flow rate or centroid-to-centroid lag time. This is consistent with increased channel velocities in hydraulically improved municipal drains, coupled with an increased proportion of storm flow being diverted from overland runoff to rapid subsurface runoff through subsurface pipe drainage. There is no evidence of appreciable changes in volumes of runoff for individual storms or as annual total streamflow or changes in seasonal distribution of streamflow. Key words: agricultural drainage, streamflow, unit hydrograph, storm runoff.

Geomorphological Approach to the Skewed Shape of Instantaneous Unit Hydrograph

2015 ◽  
Vol 48 (2) ◽  
pp. 91-103
Author(s):  
Joo-Cheol Kim ◽  
◽  
Kwansue Jung ◽  
Dong Kug Jeong
Keyword(s):  
Unit Hydrograph ◽  
Instantaneous Unit Hydrograph
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