Table Of ContentCOPYRIGHTED
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MILTON OTTO SCHMIDT
1951
FLOOD RUNOFF FROM URBAN AREAS
WITH SPECIAL REFERENCE
TO
THE SURFACE HYDROLOGY
OF
BONEYARD CREEK WATERSHED
CHAMPAIGN-URBANA, ILLINOIS
BY
MILTON OTTO SCHMIDT
B.S., University of Wisconsin, 1938
M.S., University of Wisconsin, 1941
THESIS
SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS
FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN
ENGINEERING IN THE GRADUATE COLLEGE
OF THE UNIVERSITY OF ILLINOIS, 1950
URBANA, ILLINOIS
UNIVERSITY OF ILLINOIS
THE GRADUATE COLLEGE
August 7. 1950
I HEREBY RECOMMEND THAT THE THESIS PREPARED UNDER MY
SUPERVISION *v MILTON OTTO SCHMIDT
RWTTTT.F.D FLOOD RUNOFF FROM URBAN AREAS
With Special Reference to The Surface Hydrology of
Boneyard Creek Watershed, Champaign-Urbana, I l l i n o is
BE ACCEPTED* AS FULFILLING THIS. PART OF THE REQUIREMENTS FOR
THE DEGREE OK DOCTOR OF PHILOSOPHY IN ENGINEERING
In Charge of Thesis
? t</^t>
ead of Department
Recommendation concurred inf
Committee
on
jA&PZk***
Final Examination-)-
to successful final examination in the case of the doctorate,
for doctor's degree but not f^frrfjz?ster's.
/
6M—12-48—40199K
PREFACE
There is need for a better understanding of the faotors
affecting flood runoff from small watersheds. This deficiency in
fundamental hydrologic knowledge has been emphasized repeatedly in
recent years by prominent hydraulic engineers and hydrologists. For
the most part runoff research has been conducted, sporadically on
small drainage areas because of the more immediate utility of data
obtained from large drainage areas. Furthermore, most of the occur
rences of maximum rainfall that are effective in producing floods on
small areas are associated with thunderstorms. Data and scientific
knowledge on this type of storm is not as extensive as for frontal
and orographic storm types whioh are important in the hydrology of
large catchment areas where major problems of river navigation,
hydroelectric development, and flood control are involved. There is
a .voluminous literature on floods and their control on the large
rivers but a dearth of information on the small-area flood. Hence,
increasing attention is being paid the small watershed because its
hydrologlo characteristics are intrinsically different from those
of the large watershed. Also the small watershed is physiograph-
ically and meteorologically more homogeneous which should favor the
clarification of fundamental hydrologlo interrelationships.
The urban watershed whose area is usually expressed in acres
instead of square miles is in some respects hydrologically similar
to the small natural watershed. Therefore, a first approach to the
problems of flood runoff from the urban area can be profitably
ii
obtained by considering flood runoff from small natural watersheds.
This has been done in this study.
fcc
The systematic collection of stream discharge and fM$l||lta~
tion data for a large part of the Boneyard watershed was be^i«ijFifi$ip
the summer and late fall of 1948. This action was initiated* t&tagh
the Joint efforts of the Civil Engineering Department of the Unl$
T
vereity of Illinois and the Illinois State Water Survey. 8jL|ieJ^
practically all storm drainage from Champaign and Urbana tfloWs^&lito
the Boneyard, a hydrologlo study of the watershed is a prerequisite
for the rational design of local improvement works which are needed
to alleviate the nuisances caused by periodic flooding of this
stream. The analysis of the hydrologlo data made available by the
observational program seemed an acceptable topic for a thesis study
of rainfall-runoff relations and flood runoff since few investiga
tions of a similar nature have been made for urban areas containing
such a dense distribution of recording rain gages.
The long-time extension of this study should be enlightening
as reflecting the change in land use as urban development extends
to the very divides of the watershed. ,
The author wishes to express his thanks to the members of
the staff of the Illinois State Water Survey and of the Champaign
office of the United States Geologioal Survey for their kind assist
ance in helping to make available the basic hydrologlo data used in
this study. The friendly attitude of Professor J. J. Doland, the
author's thesis adviser, and his gracious unconcern over the
seemingly-slow progress in the preparation of this dissertation is
very much appreciated.
TABLE OF CONTENTS
Page
PREFACE 13-
LIST OF TABLES •!*
LIST OF ILLUSTRATIONS vlii
I. INTRODUCTION 1
Foreword 3-
Purpose and Scope of The Research 4
Procedure 5
Results * 6
II. PREVIOUS STUDIES 8
Preliminary 8
Small Natural Watersheds 10
Runoff from Urban Areas 12
III. ANALYSIS OF THE FLOOD HYDROGRAPH 15
Fundamental Rainfall-Runoff Concepts 15
Sources of Runoff in The Boneyard Watershed 19
Factors Affecting Hydrograph Shape 21
Parts of The Hydrograph 22
Rising Limb 23
Isochronal Map 26
Crest Segment 32
Recession Limb 32
IV. BONEYARD CREEK BASIN 34
Location 34
Topography 34
Geology 36
Soils 36
Stream Characteristics 3?
Land Classification 39
Meteorology 39
V. PRECIPITATION 46
General 4®
Location and Operation of Gages 46
Excessive Precipitation Rates 48
Treatment of Rain Data 49
lv
TABLE OF CONTENTS
Page
PREFACE 11
LIST OF TABLES vii
LIST OF ILLUSTRATIONS viii
I. INTRODUCTION 1
Foreword 1
Purpose and Scope of The Research 4
Procedure 5
Results • 6
II. PREVIOUS STUDIES 8
Preliminary 8
Small Natural Watersheds 10
Runoff from Urban Areas 12
III. ANALYSIS OF THE FLOOD HYDROGRAPH 15
Fundamental Rainfall-Runoff Concepts 15
Sources of Runoff in The Boneyard Watershed 19
Factors Affecting Hydrograph Shape 21
Parts of The Hydrograph . 22
Rising Limb 23
Isochronal Map 26
Crest Segment 32
Recession Limb 32
IV. BONEYARD CREEK BASIN 34
Location 34
Topography - 34
Geology 36
Soils 36
Stream Characteristics 37
Land Classification 39
Meteorology 39
V. PRECIPITATION 46
General 46
Location and Operation of Gages 46
Excessive Precipitation Rates 48
Treatment of Rain Data 49
lv
TABLE OF CONTENTS (continued)
Page
VI. RUNOFF 59
Stream Gaging Station 59
Discharge Measurements 59
Stream Flow Records 61
Flood Flows 61
Treatment of Runoff Data 63
VII. ANALYSIS OF STORMS 69
General 69
Hydrologic Interrelationships 71
VIII. STORAGE-DISCHARGE RELATIONSHIPS 78
Channel Surveys 78
Hydrograph Analysis 78
IX. PEAK FLOODS FROM SMALL AREAS 81
Envelope Curves 81
Some Comparisons 82
X. CONCLUSIONS 85
Preliminary Scope of This Research 85
Runoff Under Thunderstorm Influence 85
Runoff from Small Urban Areas 86
Hydrologic Relationships on The Boneyard 87
Comparison with Horner and Shlfrins1 Five-year
Flood 88
Extreme Flood Flow 90
Recommendations 90
Closure 91
XI. CONTINUATION OF STUDY 94
BIBLIOGRAPHY 95
APPENDIX 99
Storm of July 22, 1948 100
Storm of July 25, 1948 102
Storm of August 13, 1948 104
Storm of September 20, 1948 106
Storm of January 18, 1949 108
Storm of January 27, 1949 119
v
TABLE OF CONTENTS (concluded)
Page
APPENDIX (continued)
Storm of February 14, 1949 129
Storm of May 19, 1949 139
Storm of July 6, 1949 149
Storm of July 26, 1949 154
Storm of August 17, 1949 159
Storm of October 2, 1949 163
Storm of October 21, 1949 173
Storm of December 20, 1949 177
Storm of January 2, 1950 179
Storm of January 25, 1950 181
Storm of April 23, 1950 189
VITA 200
vl
LIST OF TABLES
Mean Monthly Precipitation at Urbana . . -
Maximum Recorded Rainfall at Urbana . . -
Record of Rainfall Intensity - May 23, 1949
Record of Runoff - May 23, 1949
Comparative Data for Selected Storms . . -
vii
