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.

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 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 Derivation of S-Curve from Oscillatory Hydrograph Using Digital Filter

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1456
Author(s):  
Kee-Won Seong ◽  
Jang Hyun Sung
Keyword(s):  
Digital Filter ◽  
Model Performance ◽  
Performance Criteria ◽  
Rainfall Runoff ◽  
Small Watershed ◽  
Unit Hydrograph ◽  
Time To Peak ◽  
S Curve ◽  
And Performance ◽  
Smooth Data

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.

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 Integrating XAJ Model with GIUH Based on Nash Model for Rainfall-Runoff Modelling

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 772 ◽  
Author(s):  
Yingbing Chen ◽  
Peng Shi ◽  
Simin Qu ◽  
Xiaomin Ji ◽  
Lanlan Zhao ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Network Flow ◽  
Model Performance ◽  
Efficiency Coefficient ◽  
Effective Rainfall ◽  
Unit Hydrograph ◽  
Nash Model ◽  
Average Flow Velocity ◽  
Time To Peak ◽  
Flood Estimation

The geomorphologic instantaneous unit hydrograph (GIUH) is an applicable approach that simulates the runoff for the ungauged basins. The nash model is an efficient tool to derive the unit hydrograph (UH), which only requires two items, including the indices n and k. Theoretically, the GIUH method describes the process of a droplet flowing from which it falls on to the basin outlet, only covering the flow concentration process. The traditional technique for flood estimation using GIUH method always uses the effective rainfall, which is empirically obtained and scant of accuracy, and then calculates the convolution of the effective rainfall and GIUH. To improve the predictive capability of the GIUH model, the Xin’anjiang (XAJ) model, which is a conceptual model with clear physical meaning, is applied to simulate the runoff yielding and the slope flow concentration, integrating with the GIUH derived based on Nash model to compute the river network flow convergence, forming a modified GIUH model for flood simulation. The average flow velocity is the key to obtain the indices k, and two methods to calculate the flow velocity were compared in this study. 10 flood events in three catchments in Fujian, China are selected to calibrate the model, and six for validation. Four criteria, including the time-to-peak error, the relative peak flow error, the relative runoff depth error, and the Nash–Sutcliff efficiency coefficient are computed for the model performance evaluation. The observed runoff value and simulated series in validation stage is also presented in the scatter plots to analyze the fitting degree. The analysis results show the modified model with a convenient calculation and a high fitting and illustrates that the model is reliable for the flood estimation and has potential for practical flood forecasting.

scholarly journals A generalized concentration curve (GCC) method for storm flow hydrograph prediction in a conceptual linear reservoir-channel cascade

2015 ◽  
Vol 47 (5) ◽  
pp. 932-950
Author(s):  
Hui Wan ◽  
Jun Xia ◽  
Liping Zhang ◽  
Wenhua Zhang ◽  
Yang Xiao ◽  
...  
Keyword(s):  
Prediction Method ◽  
Concentration Curve ◽  
Superior Performance ◽  
Efficiency Coefficient ◽  
Storm Events ◽  
Unit Hydrograph ◽  
Small Watersheds ◽  
Storm Flow ◽  
Scope Of Application ◽  
Linear Reservoir

The unit hydrograph (UH) is a hydrological tool that represents the unit response of a watershed to a unit input of rainfall. UH models based on lumped reservoir and channel conceptual cascade assume that rainfall is evenly distributed, thus limiting the use of UHs to relatively small watersheds of less than around 500 km2 in area. In this paper, a new hydrograph prediction method, named the generalized concentration curve (GCC), was derived that can be applied to large heterogeneous watersheds. The GCC method divides the watershed into subareas by isochrones. In each subarea, an independent linear reservoir-channel cascade model that considers both attenuation and translation is established. Comparative application of the GCC and the traditional Nash instantaneous unit hydrograph to 18 storm events from three medium-sized watersheds (727, 1,800 and 5,253 km2 in area) revealed superior performance of the GCC, with the average Nash–Sutcliffe efficiency coefficient higher by 7.66%, and the average peak discharge error lower by 4.14%. This study advances the theory of UH and expands the scope of application of UH to larger watersheds.

scholarly journals Inter-comparison of surface meltwater routing models for the Greenland Ice Sheet and influence on subglacial effective pressures

2019 ◽  
Author(s):  
Kang Yang ◽  
Aleah Sommers ◽  
Lauren C. Andrews ◽  
Laurence C. Smith ◽  
Xin Lu ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Climate Model ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Hydrologic Model ◽  
Effective Pressure ◽  
Unit Hydrograph ◽  
Time To Peak ◽  
The Impact ◽  
Routing Models

Abstract. Each summer, large volumes of surface meltwater flow over the Greenland Ice Sheet (GrIS) surface and drain through moulins to the ice sheet bed, impacting subglacial hydrology and ice flow dynamics. Runoff modulations, or routing delays due to ice surface conditions, thus propagate to englacial and subglacial hydrologic systems, requiring accurate assessment to correctly estimate subglacial effective pressures and short-term lags between climatological melt production and ice velocity. This study compares hourly supraglacial moulin discharge simulations from three surface meltwater routing models, the Synthetic Unit Hydrograph (SUH), Surface Routing and Lake Filling (SRLF), and Rescaled Width Function (RWF), for four internally drained catchments (IDCs) located on the southwestern GrIS surface. Using surface runoff from the MAR regional climate model (RCM), simulated values of surface meltwater transport velocity, flow length, total transport time, unit hydrograph, peak moulin discharge, and time to peak are compared among the three routing models. For each IDC, modeled moulin hydrographs are also input to the SHAKTI subglacial hydrologic model to simulate corresponding subglacial effective pressure variations in the vicinity of a single moulin. Two routing models requiring use of a digital elevation model (SRLF, RWF) are assessed for the impact of DEM spatial resolution on simulated moulin hydrographs. Results indicate SUH, SRLF, and RWF perform differently in simulating moulin peak discharge and time to peak, with RWF simulating slower, smaller peak moulin discharges than SUH or SRLF. SRLF routing is sensitive to DEM spatial resolution, whereas RWF is not. Seasonal evolution of supraglacial stream/river networks is readily accommodated by RWF but not SUH or SRLF. In general, all three models are superior to simply using RCM output without routing, but significant differences among them are found. This variability among surface meltwater routing models is reflected in SHAKTI subglacial hydrology simulations, yielding differing diurnal effective pressure fluctuations.

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>

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
Keyword(s):  
Drainage Basin ◽  
Peak Flow ◽  
Meteorological Data ◽  
Flood Forecasting ◽  
Base Flow ◽  
Hydrologic Response ◽  
Watershed Model ◽  
Unit Hydrograph ◽  
Radar Rainfall ◽  
Time To Peak

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.

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