Estimating Debris Volumes for Flood Control

Preface

During 1991 and 1992, the California county of San Bernardino (Department of Transportation and Flood Control) funded a comprehensive study of and hydrology methods and stormflow estimation procedures used in the southwest United States. The San Bernardino County Department of Water Resources also assembled a team of experts in hydrology and storm flow estimation procedures in order to aid in reviewing recommended procedures and algorithms leading to a comprehensive flood control and floodplain stormflow estimation procedure.

Included in the expert review panel were representatives from the San Bernardino County Water Resources and Planning Divisions, Kern County Floodplain Management Division, Orange County Environmental Management Agency, the U.S. Army Corps of Engineers (Los Angeles District), Riverside County Flood Control District, the University of Arizona at Tucson, the University of California at Davis, the University of Nevada at Las Vegas, the California State University at Fullerton, and several private engineering consultants, including the firm Williamson and Schmid, under whose auspices the work was conducted.

This book provides flood control engineers and planners, floodplain managers, stormflow modelers, and researchers a valuable compendium of information on the estimation of debris volumes. It includes a general discussion of the regionalization of debris data as well as the results of an analysis of data for southern California. Equations for estimating debris volumes for exceedance frequencies from 5 to 100 years are provided. An index adjustment method is provided for estimating seasonal volumes. A model for showing the effect of watershed bum on debris volumes is also provided. Example applications of the models are included.

    Table of Contents

    Preface

    List of Appendices

    Acknowledgments

    Chapter 1 - Introduction
    1.0 Introduction
    1.1 Regionalization
    1.2 Frequency Analysis
    1.3 Overview

    Chapter 2 - Frequency Analysis
    2.1 Introduction
    2.2 Probability Paper
    2.3 Frequency Analysis Procedure
    2.4 Plotting the Data
    2.5 Analysis of Selected Populations
    2.5.1 Fitting the Normal Distribution
    2.5.2 Fitting the log Normal Distribution
    2.6 Estimating Probabilities and Magnitudes

    Chapter 3 - Zero-Flood Records
    3.1 Introduction
    3.2 Preliminary Analysis
    3.3 Check for Outliers
    3.4 Compute Unadjusted Frequency Curve
    3.5 Compute the Conditional Frequency Curve
    3.6 Compute the Synthetic Frequency Curve
    3.7 Select a Frequency Curve

    Chapter 4 - Assessing Model Reliability
    4.0 Introduction
    4.1 Model Rationality
    4.2 Bias in Estimation
    4.3 The Standard Error of Estimate
    4.4 The Correlation Coefficient
    4.5 Accuracy of Model Coefficients
    4.6 Analysis of the Residuals

    Chapter 5 - Stepwise Regression Analysis
    5.1 Objective
    5.2 Model Structure
    5.3 Total F Test
    5.4 Partial F Test
    5.5 Procedure
    5.6 Criteria for Model Selection

    Chapter 6 - Analysis of Debris Data: A Case Study
    6.1 Data Characteristics
    6.2 Drainage Density
    6.3 Hypsometric Index
    6.4 Bifurcation Ratio
    6.5 Adjustment for Watershed Bum
    6.6 Zero Flood Year Correction
    6.7 Frequency Analyses
    6.8 Regional Regression Equations
    6.9 Estimation of Seasonal Debris Volumes

    Chapter 7.0 - Applications of Debris Yield Models
    7.1 Introduction
    7.2 Application 1: Construction a Frequency Curve
    7.3 Application 2: Effect of Watershed Bum
    7.4 Application 3: Seasonal Adjustment
    7.5 Application 4: Actual Event
    7.6 Design Consideration

    Chapter 8.0 - Ratio Correlation and Regression
    8.1 Introduction
    8.2 A Hypothetical Example
    8.2.1.Concluding Remark
    8.3 Ratio Regression of Debris Yield Data
    8.4 An Actual Case Study
    8.5 Conclusions

    References

    Appendices

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