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Hydrologic Frequency Analysis



Course Outline

This course provides guidance in applying statistical principles to the analysis of hydrologic data based on the U.S. Army Corps of Engineers' Engineer Manual on Hydrologic Frequency Analysis. The manual illustrates, by example, many of the statistical techniques appropriate for hydrologic problems. The basic theory is usually not provided, but references are provided for those who wish to research the techniques in more detail. Frequency estimates of hydrologic, climatic and economic data are required for the planning, design and evaluation of water management plans. These plans may consist of combinations of structural measures such as reservoirs, levees, channels, pumping plants, hydroelectric power plants, etc., and nonstructural measures such as flood proofing, zoning, insurance programs, water use priorities, etc. The data to be analyzed could be streamflows, precipitation amounts, sediment loads, river stages, lake stages, storm surge levels, flood damage, water demands, etc. The probability estimates from these data are used in evaluating the economic, social and environmental effects of the proposed management action. The objective of frequency analysis in a hydrologic context is to infer the probability that various size events will be exceeded or not exceeded from a given sample of recorded events. Two basic problems exist for most hydrologic applications. First the sample is usually small, by statistical standards, resulting in uncertainty as to the true probability. And secondly, a single theoretical frequency distribution does not always fit a particular data-type equally well in all applications. This manual provides guidance in fitting frequency distributions and construction of confidence limits. Techniques are presented which can possibly reduce the errors caused by small sample sizes. Also, some types of data are noted which usually do not fit any theoretical distributions.

This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.


Learning Objectives

At the conclusion of this course, the student will be familiar with:

Intended Audience

This course is intended for engineers who is involved or have interest in hydrologic frequency analysis.


Benefit to Attendee

Attendee of this course will be able to gain knowledge and familiarity of procedures for frequency analysis of flood flows, low flows, precipitation, water surface elevation, and flood damage.


Course Content

The purpose of this course is to provide guidance in applying statistical principles to the analysis of hydrologic data. You will be directed to the U.S. Army Corps of Engineers' website to study Engineering and Design - Hydrologic Frequency Analysis (Engineer Manual EM 1110-2-1415, 1993 edition, 149 pages, PDF file format), which discusses the statistical principles to the analysis of hydrologic data and the statistical techniques appropriate for hydrologic problems.

Table of Contents

Chapter 1 - Introduction
Chapter 2 - Frequency Analysis
Chapter 3 - Flood Frequency Analysis
Chapter 4 - Low-Flow Frequency Analysis
Chapter 5 - Precipitation Frequency Analysis
Chapter 6 - Stage (Elevation) - Frequency Analysis
Chapter 7 - Damage-Frequency Relationships
Chapter 8 - Statistical Reliability Criteria
Chapter 9 - Regression Analysis and Application to Regional Studies
Chapter 10 - Analysis of Mixed Populations
Chapter 11 - Frequency of Coincident Flows
Chapter 12 - Stochastic Hydrology
Appendix A - Selected Bibliography
Appendix B - Glossary
Appendix C - Computation Procedure for Extreme Value (Gumbel) Distribution
Appendix D - Historic Data
Appendix E - Examples of Reliability Tests for the Mean and Standard Deviation
Appendix F - Statistical Tables

 

Related Links

For additional technical information related to this subject, please refer to:

http://water.usgs.gov/
http://www.hydrocomp.com/
http://www.sws.uiuc.edu/pubdoc/CR/ISWSCR2004-09.pdf
http://www.hec.usace.army.mil/
http://www.iwr.usace.army.mil/
http://www.wcc.nrcs.usda.gov/
http://www.epa.gov/ow/


Quiz

Once you finish studying the above course content you need to take a quiz to obtain the PDH credits.

Take a Quiz

DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.