Link to U.S. Geological Survey home page.

In cooperation with the Texas Department of Transportation

Empirical, Dimensionless, Cumulative-Rainfall Hyetographs Developed From 1959–86 Storm Data for Selected Small Watersheds in Texas

By Tara Williams-Sether1, William H. Asquith2, David B. Thompson3, Theodore G. Cleveland4, and Xing Fang5 

Scientific Investigations Report 2004–5075
(TxDOT Research Report 0–4194–3)

 

1 U.S. Geological Survey, Bismarck, North Dakota.
2 U.S. Geological Survey, Austin, Texas.
3 Texas Tech University, Lubbock, Texas.
4 University of Houston, Houston, Texas.
5 Lamar University, Beaumont, Texas.


Document Accessibility: Adobe Systems Incorporated has information about PDFs and the visually impaired. This information provides tools to help make PDF files accessible. These tools convert Adobe PDF documents into HTML or ASCII text, which then can be read by a number of common screen-reading programs that synthesize text as audible speech. In addition, an accessible version of Acrobat Reader 5.0 for Windows (English only), which contains support for screen readers, is available. These tools and the accessible reader may be obtained free from Adobe at http://access.adobe.com/.

pdf (2.33 MB)


Contents

Abstract

Introduction

Database

Previous Hyetograph Research

Research by Huff

Research by the Soil Conservation Service

Research by Pani and Haragan

Approach

Empirical, Dimensionless, Cumulative-Rainfall Hyetographs

Summary

Acknowledgments

References

Supplement 1. Descriptive Information for Streamflow-Gaging Stations Represented in Hyetograph Database

Supplement 2. Untrimmed Percentiles and Statistics for Empirical Hyetograph Analysis, 1959–86

Supplement 3. Trimmed Percentiles and Statistics for Empirical Hyetograph Analysis, 1959–86

Supplement 4. Untrimmed and Smoothed Percentiles for Empirical Hyetograph Analysis, 1959–86

Supplement 5. Trimmed and Smoothed Percentiles for Empirical Hyetograph Analysis, 1959–86

Figures

1.  
Map showing locations of streamflow-gaging stations represented in hyetograph database
2.  
Graph showing median (50th-percentile) dimensionless hyetograph curves derived from point rainfall values
3.  
Graph showing median (50th-percentile) dimensionless hyetograph curves derived from areal rainfall values
4.  
Graph showing Soil Conservation Service Type II and Type III hyetograph curves
5.  
Graph showing median (50th-percentile) dimensionless hyetograph curves for the southern High Plains of Texas
6.  
Graph showing median (50th-percentile), 10th-, and 90th-percentile composite dimensionless hyetograph curves for the southern High Plains of Texas
7.  
Examples of untrimmed (A) and trimmed (B) hyetograph data files
8.  
Graphs showing distribution of storm occurrences by storm duration
9.  
Graphs showing distribution of storm occurrences by storm-quartile classification
10.  
Graph showing median (50th-percentile) dimensionless hyetograph curves for a storm duration of 0 to 72 hours and a rainfall total of 1 inch or more
11.  
Graphs showing 10th- to 90th-percentile dimensionless hyetograph curves for a storm duration of 0 to 72 hours and a rainfall total of 1 inch or more

Tables

1.  
Example dimensionless hyetograph data
2.  
Averages and ranges for cumulative-rainfall amounts
3.  
Distribution of storm occurrence
4.  
Smoothed median (50th-percentile) distributions of rainfall with time for a storm duration of 0 to 72 hours and a rainfall total of 1 inch or more
5.  
Selected percentiles for first- and second-quartile storms for a storm duration of 0 to 72 hours and a rainfall total of 1 inch or more
6.  
Selected percentiles for third- and fourth-quartile storms for a storm duration of 0 to 72 hours and a rainfall total of 1 inch or more

Abstract

A database of incremental cumulative-rainfall values for storms that occurred in small urban and rural watersheds in north and south central Texas during the period from 1959 to 1986 was used to develop empirical, dimensionless, cumulative-rainfall hyetographs. Storm-quartile classifications were determined from the cumulative-rainfall values, which were divided into data groups on the basis of storm-quartile classification (first, second, third, fourth, and first through fourth combined), storm duration (0 to 6, 6 to 12, 12 to 24, 24 to 72, and 0 to 72 hours), and rainfall amount (1 inch or more). Removal of long leading tails, in effect, shortened the storm duration and, in some cases, affected the storm-quartile classification. Therefore, two storm groups, untrimmed and trimmed, were used for analysis. The trimmed storms generally are preferred for interpretation. For a 12-hour or less trimmed storm duration, approximately 49 percent of the storms are first quartile. For trimmed storm durations of 12 to 24 and 24 to 72 hours, 47 and 38 percent, respectively, of the storms are first quartile. For a trimmed storm duration of 0 to 72 hours, the first-, second-, third-, and fourth-quartile storms accounted for 46, 21, 20, and 13 percent of all storms, respectively.

The 90th-percentile curve for first-quartile storms indicated about 90 percent of the cumulative rainfall occurs during the first 20 percent of the storm duration. The 10th-percentile curve for first-quartile storms indicated about 30 percent of the cumulative rainfall occurs during the first 20 percent of the storm duration. The 90th-percentile curve for fourth-quartile storms indicated about 33 percent of the cumulative rainfall occurs during the first 20 percent of the storm duration. The 10th-percentile curve for fourth-quartile storms indicated less than 5 percent of the cumulative rainfall occurs during the first 20 percent of the storm duration.

Statistics for the empirical, dimensionless, cumulative-rainfall hyetographs are presented in the report along with hyetograph curves and tables. The curves and tables presented do not present exact mathematical relations but can be used to estimate distributions of rainfall with time for small drainage areas of less than about 160 square miles in urban and small rural watersheds in north and south central Texas.




FirstGov button  Take Pride in America button