Stream Channel Degradation Causes and Consequences
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ReportNo. FHWA/RD-80/038 i., ,I STREAMCHANNEL DEGRADATION ANDAGGRADATION: CAUSESAND CONSEQUENCES TOHIGHWAYS June1980 Document is available to the public through the National Technical information Service, Springfield, Virginia 22161 Preparedfar FEDERALHIGHWAY ADMINISTRATION 3 Officesof Research& Development Q EnvironmentalDivision -sea b8 Washington,D.C. 20590 FORENORD This interim report describes the first phase of a research effort on stream- channel aggradation and degradation. Gradation changes are long-term channel bed elevation changes which extend for long distances along the s treambed . This interim report describes the extent of problems nationwide, examines the causes of gradation changes, documents case studies where highway crossings have been affected, and summarizes methods available for recognizing the potential for bed level changes. During the second phase, better methods will be investigated for predicting the change in bed level, the rate of change and the stream length affected. Research in highway drainage and stream crossing design is included in Federally Coordinated Program of Highway Research and Development in Project 5H “Protection of the Highway System from Hazards Attributed to Flooding, ” Roy E. Trent is the Project Manager and Stephen A. Gilje is the Contract Manager. Sufficient copies of the report are being distributed to provide a minimum of one copy to each FHWA regional officer division office, and State highway agency. Direct distribution is being made to the division offices. Charles F. Scheffey Director, Office of Research NOTICE This document is disseminated under the sponsorship of the Department of Transportation in the interest of information exchange. The United States Government assumes no liability for its contents or use thereof. The contents of this report reflect the views of the con- tracting organization, which is responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policy of the Department of Transportation. This report does not consti- tute a standard, specification, or regulation. The United States Government does not endorse products or manufacturers. Trade or manufacturers' names appear herein only because they are considered essential to the object of this document. TECHNICAL REPORT STANDARD TITLE PAGE 1. Report No. ‘2. Government Accession No. 3. Recipient’s Catalog NO. FHWA/RD-80/b38 4. Title and Subtitle 5. Report Data Interim Report June- 1980 Stream Channel Degradation and Aggradation: 6. Performing Organization Code Causes and Consequencesto Highways SCR-342-79-016 7. Author(s) 8. Performing Organization Rapart No. T. N. Keefer, R. S. McQuivey, and D. B. Stins 9. Performing Organization Name and Address 10. Work Unit No. The Sutron Corporation 11367 11150 Main Street 11. Contract or Grant No. Fairfax, Virginia 22030 DQr-FH-11-9503 13. Type of Report and Period Covered 12. Sponsoring Agency Name and Addresc ' Interim Report Office of Research and Development October 1978 to Federal Highway Administration January 1980 U.S. Department of Transportation 14. Sponsoring Agency Code Washington, D-C.- 7fb59f1 15. Supplementary Notes FHWAContract Manager - Stephen A. Gilje (HRS-42) 16. Abstract Aggradation and degradation are long-term changes in stream channel elevation. The effects of gradation changes are not the same as local scour or erosion because they extend greater distances along the stream-bed. Degradation is a mOre cmn problem than aggradation and in general, has a mre severe impact on highway crossings. Although gradation changes do occur naturally, hm activities are responsible for the most severe cases. Channel alteration, strearn- bed mining, and the construction of dams and control structures are tk major causes of gradation problems. Virtually every river in the U.S., which flows on an alluvial bed, has a potential for gradation change. The prevalence of human activities as chief cause of gradation changes means many rivers suffer to soms degree. The best regional indicator of degradation or aggradation potential is a sediment yield map for the U.S. or areas of interest because high sediment yields correlate with ercdability. Tb aid in the anticipation of gradation changes the highway engineer should be aware of the principles of geomorphology. The simplest hydraulic analysis procedures predict the limiting slope of a gradient change based on critical shear stress of the bed material. ?"nemethods can be applied to any site where degradation or aggradation are suspected. The most complex techniques use a ccmputer solution of differential equations. These techniques are more expensive and are probably applicable only for a new bridge where gradation problems are anticipated using simple hydraulic and geanorphic Illsthds. 17. Key Words 18. Distribution Statement stream channel degradation No restrictions. Thisdccumsntis stream channel aggradation available to the public through the channel morphology National Technical InformationService stream erosion Springfield, Virginia 22161. river mechanics 19. Security Clossif. (of this report) 20. Security Clossif. (of this page) 21. No. of Pages 22. Price Unclassified Unclassified 91 Form DOT F 1700;7 (8-69) ~ . ~. .-“, _-.----.-, ____,“_~_..” ,__.. I _ _;,.. _:. ._ -c. _‘(_, . ._ ._~..^. ---..?.--...-.~- .._-----.---.- .--.i.- - -~ ---- -. _ ,.___-. --.--- ACKNOWLEDGMENT The project was initiated by Stephen A. Gilje of the Office of Research, Federal Highway Administration, who served as contract manager, reviewed this report in detail and provided significant assistance in carrying out the project. The cooperation of many individuals and agenciesin the preparation of this report is gratefully acknowledged. The authors are particularly appreciative of the efforts of all state and district engineers, who not only identified sites and supplied general information but also furnished bridge and countermeasure plans, maintenance records, and photographs for specific sites. The authors also wish to acknowledge the help of Water and Environ- mental Consultants, Inc., of Fort Collins, Colorado, which documented thirty case histories in the western United States. ii CONTENTS CHAPTER I : INTRODUCTION ................................................ .I DEFINITION OF AGGRADATION AND DEGRADATION ........................... 1 PointofView .................................................... ..l Definitions ...................................................... ..l OBJECTIVESANDSCOPE .............................................. ...2 Objectives.. ...................................................... Scope ........................................................ ...2 METHODOFSTUDY ................................................. ...3 Case Histroy Data Base. .............................................. .3 Assessment of Technology ............................................ .3 ORGANIZATIONOFREPORT ........................................... ...4 CaseHistories ................................................... ...4 Highway Problems Due To Gradation Changes ............................... .4 Appraisal of Technology. ............................................. .4 CHAPTER II: CASE HISTORY DATA BASE ....................................... .5 GENERALDESCRIPTION .............................................. ...5 RESEARCHPROCEDURES ............................................. ...5 Organization of Data Base. ............................................ .5 Source of Information ............................................... .6 EXAMPLESOFCASEHISTORIES ........................................ ...6 Case History 82 : North Fork of Walnut Creek at U.S. Highway 62 Near Blanchard, Oklahoma ........................................... .6 Case History 68 : Niobrara River Near Niobrara, Nebraska. ....................... .7 LIST OF CASE HISTORIES IN THIS REPORT ................................. .I4 OTHERAVAILABLEDATA..............................................l 4 Alaska..........................................................l 4 California........................................................l 4 Colorado ...................................................... ..17 Delaware........................................................l 8 Iowa...........................................................l 8 Kentucky ...................................................... ..18 Maryland........................................................l 8 Montana ...................................................... ..19 Oregon ....................................................... ..19 Washington.. .................................................. ..2 0 DATA OBTAINED FROM OTHER REPORTS. ................................. .20 CHAPTER III: REGIONALIZATION OF GRADATION PROBLEMS. ...................... .22 GENERALDISCUSSION.................................................2 2 REGIONS OF HIGH SEDIMENT YIELD ..................................... .22 MAJOR DRAINAGE BASINS. ............................................ .23 MissouriBasin.....................................................2 3 Lower Mississippi Basin ............................................. .23 Red-White Basin .................................................. .24 Colorado Basin ................................................... .24 SUMMARY..........................................................2 4 . 111 CHAPTER IV:, HIGHWAY PROBLEMS RELATED TO GRADATION CHANGES .............. .25 GENERAL DESCRIPTION AND APPROACH.