Logistic Analysis of Channel Pattern Thresholds: Meandering, Braiding, and Incising
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Biological Impacts of the Elwha River Dams and Potential Salmonid Responses to Dam Removal
George R. Pess1, NOAA Fisheries, Northwest Fisheries Science Center, 2725 Montlake Boulevard East, Seattle, Washington 98112 Michael L. McHenry, Lower Elwha Klallam Tribe, 2851 Lower Elwha Road, Port Angeles, Washington 98363 Timothy J. Beechie, and Jeremy Davies, NOAA Fisheries, Northwest Fisheries Science Center, 2725 Montlake Boulevard East, Seattle, Washington 98112 Biological Impacts of the Elwha River Dams and Potential Salmonid Responses to Dam Removal Abstract The Elwha River dams have disconnected the upper and lower Elwha watershed for over 94 years. This has disrupted salmon migration and reduced salmon habitat by 90%. Several historical salmonid populations have been extirpated, and remaining popu- lations are dramatically smaller than estimated historical population size. Dam removal will reconnect upstream habitats which will increase salmonid carrying capacity, and allow the downstream movement of sediment and wood leading to long-term aquatic habitat improvements. We hypothesize that salmonids will respond to the dam removal by establishing persistent, self-sustaining populations above the dams within one to two generations. We collected data on the impacts of the Elwha River dams on salmonid populations and developed predictions of species-specific response dam removal. Coho (Oncorhynchus kisutch), Chinook (O. tshawytscha), and steelhead (O. mykiss) will exhibit the greatest spatial extent due to their initial population size, timing, ability to maneuver past natural barriers, and propensity to utilize the reopened alluvial valleys. Populations of pink (O. gorbuscha), chum (O. keta), and sockeye (O. nerka) salmon will follow in extent and timing because of smaller extant populations below the dams. The initially high sediment loads will increase stray rates from the Elwha and cause deleterious effects in the egg to outmigrant fry stage for all species. -
Geomorphic Classification of Rivers
9.36 Geomorphic Classification of Rivers JM Buffington, U.S. Forest Service, Boise, ID, USA DR Montgomery, University of Washington, Seattle, WA, USA Published by Elsevier Inc. 9.36.1 Introduction 730 9.36.2 Purpose of Classification 730 9.36.3 Types of Channel Classification 731 9.36.3.1 Stream Order 731 9.36.3.2 Process Domains 732 9.36.3.3 Channel Pattern 732 9.36.3.4 Channel–Floodplain Interactions 735 9.36.3.5 Bed Material and Mobility 737 9.36.3.6 Channel Units 739 9.36.3.7 Hierarchical Classifications 739 9.36.3.8 Statistical Classifications 745 9.36.4 Use and Compatibility of Channel Classifications 745 9.36.5 The Rise and Fall of Classifications: Why Are Some Channel Classifications More Used Than Others? 747 9.36.6 Future Needs and Directions 753 9.36.6.1 Standardization and Sample Size 753 9.36.6.2 Remote Sensing 754 9.36.7 Conclusion 755 Acknowledgements 756 References 756 Appendix 762 9.36.1 Introduction 9.36.2 Purpose of Classification Over the last several decades, environmental legislation and a A basic tenet in geomorphology is that ‘form implies process.’As growing awareness of historical human disturbance to rivers such, numerous geomorphic classifications have been de- worldwide (Schumm, 1977; Collins et al., 2003; Surian and veloped for landscapes (Davis, 1899), hillslopes (Varnes, 1958), Rinaldi, 2003; Nilsson et al., 2005; Chin, 2006; Walter and and rivers (Section 9.36.3). The form–process paradigm is a Merritts, 2008) have fostered unprecedented collaboration potentially powerful tool for conducting quantitative geo- among scientists, land managers, and stakeholders to better morphic investigations. -
River Dynamics 101 - Fact Sheet River Management Program Vermont Agency of Natural Resources
River Dynamics 101 - Fact Sheet River Management Program Vermont Agency of Natural Resources Overview In the discussion of river, or fluvial systems, and the strategies that may be used in the management of fluvial systems, it is important to have a basic understanding of the fundamental principals of how river systems work. This fact sheet will illustrate how sediment moves in the river, and the general response of the fluvial system when changes are imposed on or occur in the watershed, river channel, and the sediment supply. The Working River The complex river network that is an integral component of Vermont’s landscape is created as water flows from higher to lower elevations. There is an inherent supply of potential energy in the river systems created by the change in elevation between the beginning and ending points of the river or within any discrete stream reach. This potential energy is expressed in a variety of ways as the river moves through and shapes the landscape, developing a complex fluvial network, with a variety of channel and valley forms and associated aquatic and riparian habitats. Excess energy is dissipated in many ways: contact with vegetation along the banks, in turbulence at steps and riffles in the river profiles, in erosion at meander bends, in irregularities, or roughness of the channel bed and banks, and in sediment, ice and debris transport (Kondolf, 2002). Sediment Production, Transport, and Storage in the Working River Sediment production is influenced by many factors, including soil type, vegetation type and coverage, land use, climate, and weathering/erosion rates. -
Stream Restoration, a Natural Channel Design
Stream Restoration Prep8AICI by the North Carolina Stream Restonltlon Institute and North Carolina Sea Grant INC STATE UNIVERSITY I North Carolina State University and North Carolina A&T State University commit themselves to positive action to secure equal opportunity regardless of race, color, creed, national origin, religion, sex, age or disability. In addition, the two Universities welcome all persons without regard to sexual orientation. Contents Introduction to Fluvial Processes 1 Stream Assessment and Survey Procedures 2 Rosgen Stream-Classification Systems/ Channel Assessment and Validation Procedures 3 Bankfull Verification and Gage Station Analyses 4 Priority Options for Restoring Incised Streams 5 Reference Reach Survey 6 Design Procedures 7 Structures 8 Vegetation Stabilization and Riparian-Buffer Re-establishment 9 Erosion and Sediment-Control Plan 10 Flood Studies 11 Restoration Evaluation and Monitoring 12 References and Resources 13 Appendices Preface Streams and rivers serve many purposes, including water supply, The authors would like to thank the following people for reviewing wildlife habitat, energy generation, transportation and recreation. the document: A stream is a dynamic, complex system that includes not only Micky Clemmons the active channel but also the floodplain and the vegetation Rockie English, Ph.D. along its edges. A natural stream system remains stable while Chris Estes transporting a wide range of flows and sediment produced in its Angela Jessup, P.E. watershed, maintaining a state of "dynamic equilibrium." When Joseph Mickey changes to the channel, floodplain, vegetation, flow or sediment David Penrose supply significantly affect this equilibrium, the stream may Todd St. John become unstable and start adjusting toward a new equilibrium state. -
Classifying Rivers - Three Stages of River Development
Classifying Rivers - Three Stages of River Development River Characteristics - Sediment Transport - River Velocity - Terminology The illustrations below represent the 3 general classifications into which rivers are placed according to specific characteristics. These categories are: Youthful, Mature and Old Age. A Rejuvenated River, one with a gradient that is raised by the earth's movement, can be an old age river that returns to a Youthful State, and which repeats the cycle of stages once again. A brief overview of each stage of river development begins after the images. A list of pertinent vocabulary appears at the bottom of this document. You may wish to consult it so that you will be aware of terminology used in the descriptive text that follows. Characteristics found in the 3 Stages of River Development: L. Immoor 2006 Geoteach.com 1 Youthful River: Perhaps the most dynamic of all rivers is a Youthful River. Rafters seeking an exciting ride will surely gravitate towards a young river for their recreational thrills. Characteristically youthful rivers are found at higher elevations, in mountainous areas, where the slope of the land is steeper. Water that flows over such a landscape will flow very fast. Youthful rivers can be a tributary of a larger and older river, hundreds of miles away and, in fact, they may be close to the headwaters (the beginning) of that larger river. Upon observation of a Youthful River, here is what one might see: 1. The river flowing down a steep gradient (slope). 2. The channel is deeper than it is wide and V-shaped due to downcutting rather than lateral (side-to-side) erosion. -
Floodplain Heterogeneity and Meander Migration
River, Coastal and Estuarine Morphodynamics: RCEM2011 © 2011 Floodplain heterogeneity and meander migration MOTTA Davide Department of Civil and Environmental Engineering University of Illinois at Urbana-Champaign, Urbana, Illinois, USA E-mail: [email protected] ABAD Jorge D. Department of Civil and Environmental Engineering University of Pittsburgh, Pittsburgh, Pennsylvania, USA E-mail: [email protected] LANGENDOEN Eddy J. US Department of Agriculture, Agricultural Research Service National Sedimentation Laboratory, Oxford, Mississippi, USA E-mail: [email protected] GARCIA Marcelo H. Department of Civil and Environmental Engineering University of Illinois at Urbana-Champaign, Urbana, Illinois, USA E-mail: [email protected] ABSTRACT: The impact of horizontal heterogeneity of floodplain soils on rates and patterns of meander migration is analyzed with a Ikeda et al. (1981)-type model for hydrodynamics and bed morphodynamics, coupled with a physically-based bank erosion model according to the approach developed by Motta et al. (2011). We assume that rates of migration are determined by the resistance to hydraulic erosion of the soils, which is described by an excess shear stress relation. This relation uses two parameters characterizing the resistance to erosion: critical shear stress and erodibility coefficient. The spatial distribution of critical shear stress in the floodplain is generated on a regular grid with varying degree of randomness to mimic natural settings and the corresponding erodibility coefficient is computed with a relation derived from field-measured pairs of critical shear stress and erodibility. Centerline migration and associated statistics for randomly-disturbed distribution based on the distance from the valley axis are compared for sine-generated centerline using the Monte Carlo method. -
Sediment-Triggered Meander Deformation in the Amazon Basin
Sediment-triggered meander deformation in the Amazon Basin Joshua Ahmed, José A. Constantine & Thomas Dunne 1 Jose A. Constantine, Thomas Dunne, Carl Legleiter & Eli D. Lazarus Sediment and long-term channel and floodplain evolution across the Amazon Basin 2 Meandering rivers & their importance 3 Controls on meander migration • Curvature • Discharge • Floodplain composition • Vegetation • Sediment? 4 Alluvial sediment • The substrate transported through our river systems • The substrate that builds numerous bedforms, the bedforms that create habitats, the same material that creates the floodplains on which we build and extract our resources. Yet there is supposedly no real connection between this and channel morphodynamics? 5 6 7 Study site: Amazon Basin 8 9 What we did • methods 10 Results 11 Results 12 Results 13 Results 14 Results 15 Proposed mechanisms 16 Summary • Rivers with high sediment supplies migrate more and generate more cutoffs • Greater populations of oxbow lakes (created by cutoffs) mean larger voids in the floodplain • Greater numbers of voids mean more potential sediment accommodation space (to be occupied by fines) • DAMS – connectivity • Rich diversity of habitats 17 36,139 ha Dam, Maderia Finer and Olexy, 2015, New dams on the Maderia River 18 For further information 19 For more information Ahmed et al. In prep i.e., coming soon… to a journal near you 20 References • Constantine, J. A. and T. Dunne (2008). "Meander cutoff and the controls on the production of oxbow lakes." Geology 36(1): 23-26. • Dietrich, W. E., et al. (1979). "Flow and Sediment Transport in a Sand Bedded Meander." The Journal of Geology 87(3): 305-315. -
Relationships Among Basin Area, Sediment Transport Mechanisms and Wood Storage in Mountain Basins of the Dolomites (Italian Alps)
Monitoring, Simulation, Prevention and Remediation of Dense Debris Flows II 163 Relationships among basin area, sediment transport mechanisms and wood storage in mountain basins of the Dolomites (Italian Alps) E. Rigon, F. Comiti, L. Mao & M. A. Lenzi Department of Land and Agro-Forest Environments, University of Padova, Legnaro, Padova, Italy Abstract The present work analyses the linkages between basin geology, shallow landslides, streambed morphology and debris flow occurrence in several small watersheds of the Dolomites (Italian Alps). Field survey and GIS analysis were carried out in order to seek correlations among basin area, basin geology, spatial frequency of landslides, in-channel wood storage, and local bed slope. Keywords: large woody debris, landslides, bed morphology, Alps. 1 Introduction Along with sediments, shallow landslides in forested basins supply channels with wood elements, which may have a strong impact on both channel morphology/stability and on debris flow dynamics. Headwater channels, which make up 60–80% of the cumulative channel length in mountainous terrain [10, 11], are characterized by a strong coupling between hillslope and channel processes, in contrast to lowland streams. The switch between different transport mechanisms (e.g., bedload transport to debris flows) in the same channel often depends on the occurrence of shallow landslides feeding sediment in otherwise sediment-limited systems. Along with sediments, shallow landslides in forested basins supply channels with wood elements, which may have a strong impact on both channel morphology/stability WIT Transactions on Engineering Sciences, Vol 60, © 2008 WIT Press www.witpress.com, ISSN 1743-3533 (on-line) doi:10.2495/DEB080171 164 Monitoring, Simulation, Prevention and Remediation of Dense Debris Flows II and on debris flow dynamics. -
Horizons River and Channel Morphology Report Version3
River and channel morphology: Technical Report prepared for Horizons Regional Council Measuring and monitoring channel morphology Dr. Ian Fuller Geography Programme School of People, Environment & Planning March 2007 River and channel morphology: Technical Report prepared for Horizons Regional Council Measuring and monitoring channel morphology Author: Dr. Ian Fuller Geography Programme School of People, Environment & Planning Reviewed By: Graeme Smart Fluvial Scientist NIWA Cover Photo: Tapuaeroa River, East Cape March 2007 Report 2007/EXT/773 FOREWORD As part of a review of the Fluvial Research Programme, Horizons Regional Council have engaged experts in the field of fluvial geomorphology to produce a report answering several key questions related to channel morphology and linkages with instream habitat diversity in Rivers of the Manawatu-Wanganui Region. This report is aimed at introducing concepts of the importance of morphological diversity in the Region’s rivers to the planning framework (to be used in the development of Horizons second generation Regional Plan – the One Plan). This expert advice has been used in the development of permitted activity baselines for activities in the beds of rivers and lakes which may influence the channel morphology and to address the cumulative impacts of these activities over time and space. Monitoring recommendations within this report provide guidance for the management of cumulative reductions in channel morphological diversity over time. Regional implementation of the monitoring of channel morphology is planned for introduction in the 2007/08 financial year through the newly reviewed Fluvial Research Programme. The monitoring will be conducted in line with recommendations from this report. Kate McArthur Environmental Scientist – Water Quality Horizons Regional Council ii CONTENTS Foreword i Contents 3 1. -
TRCA Meander Belt Width
Belt Width Delineation Procedures Report to: Toronto and Region Conservation Authority 5 Shoreham Drive, Downsview, Ontario M3N 1S4 Attention: Mr. Ryan Ness Report No: 98-023 – Final Report Date: Sept 27, 2001 (Revised January 30, 2004) Submitted by: Belt Width Delineation Protocol Final Report Toronto and Region Conservation Authority Table of Contents 1.0 INTRODUCTION......................................................................................................... 1 1.1 Overview ............................................................................................................... 1 1.2 Organization .......................................................................................................... 2 2.0 BACKGROUND INFORMATION AND CONTEXT FOR BELT WIDTH MEASUREMENTS …………………………………………………………………...3 2.1 Inroduction............................................................................................................. 3 2.2 Planform ................................................................................................................ 4 2.3 Meander Geometry................................................................................................ 5 2.4 Meander Belt versus Meander Amplitude............................................................. 7 2.5 Adjustments of Meander Form and the Meander Belt Width ............................... 8 2.6 Meander Belt in a Reach Perspective.................................................................. 12 3.0 THE MEANDER BELT AS A TOOL FOR PLANNING PURPOSES............................... -
Objective Identification of Pools and Riffles in a Human-Modified Stream System
Middle States Geographer, 2002, 35:52-60 OBJECTIVE IDENTIFICATION OF POOLS AND RIFFLES IN A HUMAN-MODIFIED STREAM SYSTEM Kelly M. Frothingham and Natalie Brown Department of Geography & Planning, Buffalo State College 1300 Elmwood Avenue Buffalo, NY 14222 ABSTRACT: Pools have been defined as topographic lows along a longitudinal stream profile and riffles are topographic highs. Past research has shown pools and riffles are the fundamental bedforms in meandering streams and that channel cross sections in meandering channels exhibit varying degrees of asymmetry that coincide with these bed form features. Two indices that identify pool and riffle bed forms are the bed differencing technique (bdt) developed by O'Neill and Abrahams (1984) and the areal difference asymmetry index (A') (Knighton. 1981). The purpose of this research was to use these indices to objectively identify pools and riffles in three reaches of a human-modified stream. Geomorphological data were collected in two meandering reaches and one straight reach ofthe East Branch ofCazenovia Creek, NY. Between 16 and 19 cross sections were surveyed in each reach during summer low flow conditions. The bdt identified more bed forms in the meandering reaches versus the straight channelized reach (six and two bed forms, respectively). Results from the asymmetry' analysis indicated that more cross sections in the two meandering reaches were asymmetrical (71 and 73% ofthe cross sections) versus 47% of the cross sections being asymmetrical in the straight reach. Moreover, asymmetrical cross sections generally corresponded with pool bed forms identified by the bdt and symmetrical cross sections corresponded with riffle bed forms identified hy the bdt. -
Re-Creating Meander Geometry Photo(S)
Practice Title Re-creating meander geometry Photo(s) Greene County streams after their meander geometry was restored to the extent necessary to move sediment and flow without excess erosion or deposition (bottom photos). The proper meander geometry is determined through detailed stream assessment. Also, a diagram showing the typical position of pools and riffles within a meandering stream, and a few other stream meander geometry patterns (top). Summary of Practice The winding pattern of a river or stream is called its meander pattern. These meanders result in a longer channel with a lower slope. These curves slow down the water and absorb energy, which helps to reduce the potential for erosion. The velocity of a stream is typically greatest on the outside of a meander bend. The increased force of this water often results in erosion along this bank, extending a short distance downstream. On the inside of the bend, the stream velocity typically decreases, which often results in the deposition of sediment, usually sand and gravel. If you could look at the long-term history of a valley over hundreds or thousands of years, you would see that the stream has moved back and forth across the valley bottom. In fact, this lateral migration of the channel, accompanied by down cutting, is what has formed the valley. Success in stream management is based on working with the stream, not against it. If a reach of channel is suffering unusual bank erosion, down cutting of the bed, aggradation, change of channel pattern, or other evidence of instability, a realistic approach to addressing these problems should be based on restoring the system’s equilibrium.