Academia.eduAcademia.edu

Outline

Title
Abstract
Introduction
Conclusion
References
All Topics
Engineering
Civil Engineering

Storm-Water Predictions by Dimensionless Unit Hydrograph

Profile image of James Chwen Yuan GuoJames Chwen Yuan Guo

2006, Journal of Irrigation and Drainage Engineering

https://doi.org/10.1061/(ASCE)0733-9437(2006)132:4(410
visibility

…

description

10 pages

link

1 file

Abstract

This paper presents a theoretical derivation of a dimensionless unit hydrograph using the kinematic wave approach. The dimensionless kinematic wave unit hydrograph ͑KWUH͒ is normalized by the parameters associated with the equilibrium condition and can be generated according to the selected rainfall duration. For comparison, a KWUH whose rainfall duration is equal to the time of equilibrium produces good agreement with the Soil Conservation Service dimensionless unit graph ͑SCSUH͒. Both the KWUH and SCSUH are kinematic in nature and have a 37.5% runoff volume that occurred before the time to peak. To verify the applicability of the KWUH derived in this study, a set of hypothetical rectangular watersheds ranging from 20 to 200 acres was investigated. The predicted 100-year peak flow rates from these five hypothetical rectangular watersheds are compared with the SCSUH method and the Colorado Unit Hydrograph Procedures ͑CUHP͒. In general, the KWUH produces good agreement with the CUHP when the catchment has an area between 60 and 120 acres. Based on the study of hypothetical rectangular watersheds, it is recommended that the KWUH be applicable to urban catchments with a drainage area of up to 120 acres.

Related papers

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

International journal of agricultural invention, 2017

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

View PDFchevron_right
Instantaneous Unit Hydrograph Evaluation for Rainfall-Runoff Modeling of Small Watersheds in North and South Central Texas
Xing Fang

Journal of Irrigation and Drainage Engineering-asce, 2006

Data from over 1,600 storms at 91 stations in Texas are analyzed to evaluate an instantaneous unit hydrograph IUH model for rainfall-runoff models. The model is fit to observed data using two different merit functions: a sum of squared errors function, and an absolute error at the peak discharge time QpMAX function. The model is compared to two other models

View PDFchevron_right
On hydrologic similarity: 3. A dimensionless flood frequency model using a generalized geomorphologic unit hydrograph and partial area runoff generation
Murugesu Sivapalan

1990

One of the shortcomings of the original theory of the geomorphologic unit hydrograph (GU H) is that it assumes that runoffis generated uniformly from the entire catchment area. It is now recognized that in many catchments much of the runoff during storm events is produced on partial areas which usually form on narrow bands along the stream network.

View PDFchevron_right
An analysis of the dynamic component of the geomorphologic instantaneous unit hydrograph
Enda O'Connell

Journal of Hydrology, 1996

The determination of characteristic flow velocity is a hydrodynamic problem needs to be solved in the application of geomorphologic instantaneous unit hydrograph (GIUH) for runoff simulation in areas with no or limited data. In this study, 120 watersheds are collected to construct a regression model; 85 of these basins are used for regression analysis, and the 35 remaining basins are utilized to verify the feasibility of the constructed model. Random forest algorithm is applied to screen out important geomorphologic factors from the 16 extracted factors that may affect flow velocity. Multivariate regression is used to establish the numerical relationship between velocity and the selected factors. Sensitivity analysis of each adopted factor in the constructed model is conducted using the LH-OAT method. The rationality and feasibility of the regression model are validated by comparing the flow velocity calculation with a previous approach, which is also calculated based on geomorphological parameters. Subsequently, the runoff simulation based on the GIUH model is evaluated using the proposed technique. Results demonstrate that the proposed formula possesses high fitting accuracy and can be easily used to calculate flow velocity and generate GIUH.

View PDFchevron_right
Evaluation of synthetic unit hydrograph methods for the development of design storm hydrographs for Rivers in South-West, Nigeria
A.W. Salami

J Am Sci, 2009

This report presents the establishment of appropriate method of synthetic unit hydrograph to generate ordinates for the development of design storm hydrographs for the catchment of eight selected rivers located in the South West Nigeria. Unit hydrographs were developed based on Snyder, Soil Conservation Service (SCS) and Gray methods; while the SCS curve Number method was used to estimate the cumulative rainfall values for storm depth of different return periods. The peak storm hydrographs corresponding to the excess rainfall values were determined based on the unit hydrograph ordinates established. The peak storm hydrograph flows obtained based on the unit hydrograph ordinate determined by Snyder for 20-yr, 50-yr, 100-yr, 200-yr and 500-yr, return period varies from 112.63m 3 /s and 13364.30m 3 /s, while those based on the SCS varies from 304.43m 3 /s and 6466.84m 3 /s and those based on Gray varies from 398.06m 3 /s and 2607.42m 3 /s for the eight watersheds. The analysis shows that the values of peak flows obtained by Gray and SCS methods for five watershed were relatively close, while the values of peak flows obtained by Gray and Snyder methods for two watershed were relatively close and the values of peak flows obtained by Snyder and SCS methods for only one watershed was relatively close. This inferred that SCS method can be used to estimate ordinate required for the development of peak storm hydrograph of different return periods for the river watersheds considered.

View PDFchevron_right
Modified Rational Unit Hydrograph Method and Applications
Nirajan Dhakal, Xing Fang
View PDFchevron_right
SYNTHETIC UNIT HYDROGRAPH
Sofia Marquez Rey

Equations are developed for computing the unit hydrograph for ungaged watersheds. The two-parameter gamma function unit hydrograph from the HYMO hydrologic model is used in the study and equations for estimating the time to peak and the recession constant are developed. The equations use physical characteristics of the drainage basin to predict the parameters for the unit hydrograph. Stepwise regression analysis is used to reduce the number of physical and hydrological variables to four, which are the basin area, height, length, and watershed slope. Records of 283 storm events from 85 watersheds in 13 states were studied to develop and verify the equations. Results of the study indicate that these equations can be used to more accurately estimate the runoff hydrograph than the SCS (Soil Conservation Service) dimensionless unit hydrograph procedure for mild and steep watershed slopes. J. Water Resour. Plann. Manage. 1987.113:70-81. Downloaded from ascelibrary.org by University of Exeter on 07/14/15. Copyright ASCE. For personal use only; all rights reserved.

View PDFchevron_right
Unit Hydrograph Modeling using Geomorphological Instantaneous Unit Hydrograph (GIUH) Method
Adam Pamudji Rahardjo

Journal of the Civil Engineering Forum

Flood forecasting at Wonogiri Reservoir is restricted on the availability of hydrologic data due to limited monitoring gauges. This issue triggers study of unit hydrograph modeling using Geomorphological Instantaneous Unit Hydrograph (GIUH) which is based on Geographic Information System (GIS). Analysis of physical watershed parameters was conducted on Digital Elevation Model (DEM) data using software Watershed Modeling System (WMS) 10.1 and ArcGIS. Nash model and S-curve method were used to process triangular GIUH into hourly Instantaneous Unit Hydrograph (IUH) and Unit Hydrograph (UH) and then was compared with the observed UH of Collins method. A sensitivity analysis was conducted on parameter of RL and Nash-model k. Evaluation of accuracy of the simulated GIUH runoff hydrograph was also conducted. The GIUH model generated UH with smaller peak discharge Qp, also slower and longer of tp and tb values than the observed UH. Accuracy test of the simulated GIUH runoff hydrograph using...

View PDFchevron_right
A Review of Synthetic Hydrograph Methods for Design Storm
Tejaswini Bhagwat

2019

The main aim of this paper is to determine the suitable method of synthetic unit hydrograph for various ungauged or data paucity watershed characteristics, where each method specified in range of validity based on characteristics parameter and will be presented in the form of synthetic unit hydrograph methods. For this purpose, the Synthetic unit hydrograph methods were first grouped into four main classes, as follows: (1) Traditional methods; (2) Conceptual methods; (3) probabilistic methods; and (4) geomorphological methods. This evaluation is expected to be helpful to academician and students to study the unit hydrograph, modeling techniques and related processes in ungauged or data paucity basins. Synthetic method validation is done by calculating the comparison parameters between observation and synthetic unit hydrograph with the specified acceptance value. Comparison parameters measure the similarity of the unit hydrograph’s shape and the unit hydrograph parameters of the peak...

View PDFchevron_right
Field Test on Conversion of Natural Watershed into Kinematic Wave Rectangular Plane
Leonard Wright

Journal of Hydrologic Engineering, 2012

Conversion of a natural watershed into its equivalent kinematic wave rectangular plane has long been a concern in the practice of stormwater numerical simulations. Based on the principles of mass and energy, the actual watershed and its virtual kinematic wave plane can be related by the watershed shape factor that involves the waterway length and slope, and watershed area. In this study, two dimensionless watershed shape functions are derived to use parabolic function and trigonometric Sine curve for watershed conversion. These two watershed shape functions produce good agreements with the maximum overland flow length method for hypothetical square watersheds. Also, these two watershed shape functions are able to reproduce similar kinematic wave plane widths as reported in a calibrated model. Furthermore, in this study, these two watershed shape functions are tested by nine observed rainfall events and three levels of modeling details. These 54 case studies reveal that the parabolic shape function consistently produces better agreements with the observed runoff hydrographs. Also, a model with more drainage details results in more concentrated flows or higher peak flows. On the contrary, a model with a low resolution tends to decrease the peak flow because of the significant surface detention volume spread in the overland flow.

View PDFchevron_right

References (21)

  1. Bedient, P. B., and Huber, W. C. ͑1992͒. Hydrology and floodplain analysis, 2nd Ed., Addison-Wesley, New York.
  2. Beuter, E. L., Gaebe, R. R., and Horton, R. E. ͑1940͒. "Sprinkled-plate runoff and infiltration experiments on Arizona desert soils." Trans., Am. Geophys. Union, 550-558.
  3. Chow, V. T. ͑1962͒. Handbook of applied hydrology, Chap. 17 and 21, McGraw-Hill, New York.
  4. Chow, V. T., Maidment, D. R., and Mays, L. W. ͑1976͒. Applied hydrol- ogy, McGraw-Hill, New York.
  5. Eagleson, P. S. ͑1970͒. Dynamic hydrology, McGraw-Hill, New York, 344-346. Federal Highway Administration ͑FHwA͒. ͑1983͒. "Inlet design program." Rep. No. FHWA/RD-83/043, Vol. 3, FHwA, Washington, D.C. Guo, J. C. Y. ͑1998͒. "Overland flow on a pervious surface." Int. J. Water, 23͑2͒.
  6. Guo, J. C. Y. ͑2000a͒. "A semi-virtual watershed model by neural networks." J. Comput.-Aided Eng., Special Issue for Evolutionary and Neural Network Computing, Vol. 15.
  7. Guo, J. C. Y. ͑2000b͒. "Storm hydrographs for small catchments." Int. J. Water, 25͑3͒.
  8. Guo, J. C. Y. ͑2001͒. "Rational hydrograph method for small urban catchments." J. Hydrologic Eng., 6͑4͒.
  9. Guo, J. C. Y., and Urbonas, B. ͑1988͒. "Colorado unit hydrograph procedures-Its synthetic unit hydrograph characteristics." Proc., ASCE Conf. on Hydraulic Engineering, ASCE, New York.
  10. Lighthill, M. H., and Whitham, G. B. ͑1955͒. "On kinematic waves. I: Flood movement in long rivers." Proc. R. Soc. London, Ser. A, 229, 281-316.
  11. McCuen, R. H. ͑1982͒. A guide to hydrologic analysis using SCS methods, Prentice-Hall, New York.
  12. Morgali, J. R. ͑1970͒. "Laminar and turbulent overland flow hydro- graphs." J. Hydraul. Div., Am. Soc. Civ. Eng., 96͑2͒, 441-360.
  13. Sherman, L. K. ͑1932͒. "Streamflow from rainfall by the unit-graph method." Eng. News-Rec., 108 501-505.
  14. Snyder, W. M. ͑1955͒. "Hydrograph analysis by the method of least squares." Proc. Am. Soc. Civ. Eng., 81, 1-25.
  15. Soil Conservation Service ͑SCS͒. ͑1957͒. Use of storm and watershed characteristics in synthetic hydrograph analysis and application, U.S. Dept. of Agriculture, Washington, D.C. Soil Conservation Service ͑SCS͒. ͑1972͒. SCS national engineering handbook, Section 4: Hydrology, U.S. Dept. of Agriculture, Washington, D.C. Soil Conservation Service ͑SCS͒. ͑1986͒. "Urban hydrology for small watersheds." Technical Release No. 55. NTIS PB87-101580, U.S. Dept. of Agriculture, Washington, D.C.
  16. Urbonas, B. ͑1979͒. "Reliability of design storms in modeling." Proc., Int. Symp. on Urban Storm Runoff, Univ. of Kentucky, July 23-26, Lexington, Ky.
  17. Urban Drainage and Flood Control District ͑Urban͒. ͑2001͒. Urban storm water drainage criteria manual, Urban Drainage and Flood Control District, Denver.
  18. U.S. Army Corps of Engineers ͑USACE͒. ͑1985͒. HEC-1 flood hydrograph package, Hydrologic Engineering Center, Davis, Calif.
  19. Wooding, R. A. ͑1965͒. "A hydraulic model for a catchment-stream problem." J. Hydrol., 3 254-267.
  20. Woolhiser, D. A., and Liggett, J. A. ͑1967͒. "Unsteady one-dimensional flow over a plane-The rising hydrograph." Water Res., 3͑3͒, 753-771.
  21. Yen, B. C., and Chow, V. T. ͑1974͒. "Experimental investigation of watershed surface runoff." Hydraulic Engineering Series, No. 29, Dept. of Civil Engineering, Univ. of Illinois at Urbana-Champaign, Ill.

Related papers

A morpho-climatic instantaneous unit hydrograph model for urban catchments based on the kinematic wave approximation
Larry Roesner

Journal of Hydrology, 2009

Stormwater models are valuable tools in urban planning as well as stormwater system design and management. Although the hydraulic simulation of pipes and channels in these models is often quite sophisticated, the hydrologic simulation of the flow contributing to the hydraulic elements is frequently greatly simplified. Hydrologic simulation of urban catchments is made particularly complex due to the presence of features such as streets, small pipes, and channels. In this study, we develop a new model called the U-McIUH (Urban Morpho-climatic Instantaneous Unit Hydrograph), which defines the IUH as the probability density function of the travel time from a random location in the urban terrain to the outlet. Flow paths are extracted from a specially processed digital elevation model that incorporates hillslopes, streets, pipes, and channels, and travel times are computed in each cell using the average wave celerity from kinematic wave theory. These expressions depend on the upstream contribution of flow and the excess rainfall intensity, so they incorporate the so-called climatic dependence of the IUH, which is the dependence of the unit hydrograph on the rainfall intensity. Rainfall pulses of different intensities are convoluted with their respective IUH and superimposed to generate the response to a given storm event. The application of the model to a real catchment provides good reproduction of observed hydrographs, suggesting that the U-McIUH is able to capture some significant hydrologic properties of the catchment. The model is studied by analyzing the effects of (1) the upstream contribution of flow on the travel time formulation, (2) the variation of flow velocities within the urban catchment, (3) the non-linear dependence of the IUH on the rainfall intensity (i.e. the climatic dependence), and (4) the spatial distribution of imperviousness. Overall, these results suggest that the presence of artificial elements in urban watersheds has a significant role in determining the travel times and thus the hydrologic response of the watershed.

View PDFchevron_right
Prediction and Modeling of Flood Hydrology and Hydraulics
Jorge Ramirez

Human, Riparian, and Aquatic Communities, 2000

The basic principles underlying the most commonly used physically-based models of the rainfall-runoff transformation process are reviewed. A thorough knowledge of these principles is a pre-requisite for flood hazard studies and, thus, this chapter reviews several physically-based methods to determine flood discharges, flow depths, and other flood characteristics. The chapter starts with a thorough review of linear system theory applied to the solution of hydrologic flood routing problems in a spatially aggregated manner --Unit Hydrograph approaches. The chapter then proceeds to a review of distributed flood routing approaches, in particular the kinematic wave and dynamic wave approaches. The chapter concludes with a brief discussion about distributed watershed models, including single event models in which flow characteristics are estimated only during the flood, and continuous event models in which flow characteristics are determined continuously during wet periods and dry periods.

View PDFchevron_right
Development of Guidance for Runoff Coefficient Selection and Modified Rational Unit Hydrograph Method for Hydrologic Design
Nirajan Dhakal

2012

The rational method is the most widely used method by hydraulic and drainage engineers to estimate design discharges. The runoff coefficient (C) is a key parameter for the rational method. Literature-based C values (C lit ) are listed for different land-use/landcover conditions in various design manuals and textbooks, but C lit appear not to be derived from any observed data. In this study, C lit values were derived for 90 watersheds in Texas from two sets of land-cover data for 1992 and 2001. C values were also estimated using observed rainfall and runoff data for more than 1,600 events in the study watersheds using two different approaches (1) the volumetric approach (C v ) (2) the ratebased approach (C rate ).When compared with the C v values, about 80 percent of C lit values were greater than C v values. This result might indicate that literature-based C overestimate peak discharge for drainage design when used with the rational method.

View PDFchevron_right
Unit hydrograph based forecast model
Subhash Chander

Hydrological Sciences Journal, 1984

The paper presents a procedure for the on-line estimation of the (j)-index and rainfall excess as a storm progresses in time. This enables the application of a unit hydrograph model in real-time river flow forecasting. The rainfall and runoff readings up till the time of forecast are used to obtain the current estimate of the cj)-index and rainfall excess. The rainfall excess thus computed is convolved with the unit hydrograph to formulate the forecast. The success of the suggested procedure is demonstrated on two Indian catchments. Modèle de prévision basé sur 1'hydrogramme unitaire RESUME Dans cet article on propose la forme discrète du modèle de 1'hydrogramme unitaire pour le calcul des prévisions sur deux bassins indiens. Le modèle exige la connaissance de la pluie excédentaire au fur et à mesure que les précipitations progressent dans le temps. Les lectures de précipitations et de débits jusqu'au moment de la prévision sont rapportées au taux de réduction moyen pour atteindre l'objectif ci dessus. On discute des résultats et on conclut que ce modèle simple donne de bons résultats sur les bassins étudiées.

View PDFchevron_right
Conversion of Natural Watershed to Kinematic Wave Cascading Plane
Behzad Ahmadi

Storm water management models using the kinematic wave ͑KW͒ approach require the conversion of a natural watershed to its equivalent rectangular cascading plane. AKW cascading plane is specified by the plane's area, width, and slope. Without on-site calibration, there is no guidance on how to translate the irregularity of a natural watershed into a rectangular shape that has an equivalent hydrologic response. As a result, the reliability of a KW model depends on an engineer's experience. Often the use of a computer model to simulate stormwater runoff is the only option because there are not field data at the project site to use statistical methods. The need for calibration at each site defeats the purpose for using computer simulations. This long existing problem has been documented in the EPA SWMM4 User Manual, which continued into the EPA SWMM5 user guidance. In this study, the continuity and energy principles are creatively interpreted as the preservations of watershed area and vertical fall over the receiving waterway's length. The dimensional analysis suggests that the watershed shape factor can be used to correlate the waterway length in the natural watershed to the KW plane width. A parabolic one-to-one single valued function was derived to translate the watershed shape into its equivalent KW plane width, length, and slope. After numerous tests, it is confirmed that the watershed and KW shape factors provide a consistent and stable basis for watershed geometric conversion. It is believed that the procedure outlined in this paper can be very useful to the KW surface runoff modeling to represent urban stormwater predictions when an on-site calibration is not readily available.

View PDFchevron_right

Related topics

  • Civil Engineering
  • Environmental Science
  • Irrigation and Drainage Engineering
  • Interdisciplinary Engineering
    • 580 California St., Suite 400
    San Francisco, CA, 94104
    © 2025 Academia. All rights reserved