DOCSLIB.ORG

Iron Canyon Watershed.···,· "'

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Iron Canyon Watershed.···,· Preface This Watershed Analysis is presented as ·part of the Aquatic Conservation Str:9-tegy adopted for the President's Plan (Record of Decision for Amendments to Forest Service and.Bureau ofLand Management Planning Documents within the R'ang'e of the Northern Spotted Owl, including Standards and Guidelines for Management of Habitat for Late-Succ~ssional ,and Old-Growth Related Species). .,'.. ·:., ·.. ·. .•.·.· . Announcements were published in local newspapers in ReddinP; and ~~.ni.them Si~,kjyou C,ounty inviting public input to this analysis. Open Houses were held ill Reddirig,' 11c.Cloud ahd,Big ·J3end,"\vhere resource specialists presented information on existing conditions and manag~ment direction for National Forestlands within the Iron Canyon Watershed.···,· "': The Iron Canyon Watershed Analysis was prepared with input and irivolvement from the following resource specialists: · ' · ..., .. o - . Charles Miller Forester/Team Leader . .i McCloud Ranger District Nancy Hutchins · Wildlife Biologist· : · · : · Shasta Lake Ranger District Bill Brock Fisheries Biologist .U.S.Fish and Wildlife Service Becky May Fire Management Officer · Shasta I:.ake Ranger District Rhonda Posey · · Ecologist Shasta Lake Ranger District Chuck McDonald SilViculturist Mount Shasta Ranger District Abel Jasso Geologist Shasta take Ranger District Ken Lanspa Soil Scientist Shasta,-.. Trinity National Forests Norman Braithwaite Hydrologist ·North State Resources Joe Zustak · .. Fisheries Biologist . · Shasta Lake Ranger District JeffHuhtala Engineering Technician. · Moimt Shasta Ranger District Paula ·crumpton . .. Wildlife Biologist/Teairi Cmich . ··shasta-Tpnity National Forests Dave Simons Writer/Editor McCloud Ranger District Additional input was provided by: Elaine Sundahl Archaeologist . Shasta Lake Ranger District Mary Ellen Grigsby Recreation Specialist · ·· ·shaSta Lak~ Ranger District Jonna Cooper · · Geographic Inforrilati9n:Systems McCloud Ra~gerDistrict · . - .. ·i . ·.· ... .: .·._: . ·. .. ~ '· .· ··: .. ... : .. .:~ : ... - Table of Contents Iron Canyon Watershed Analysis Table of Contents Preface Table of Contents Chapter 1- Characterization of the Iron Canyon Watershed 1-1 + Location and land management relationships....................... 1- 1 Map 1. Vicinity Map Map 2. Dominant Features Map 3. Private Ownership Map 4. Late-Successional Reserve RC-335 . + Physical features of the watershed....................................... 1- 2 + Late-successional forests and habitat................................... 1.: 2 Map 5. Late-successional Forest + Riparian and aquatic ecosystems......................................... 1- 3 + Social characteristics and uses ..... ~....................................... 1- 4 Chapter 2- Issues and Key Questions ................... ·...... ,.............. 2-1 + Lack and loss of late-successional habitat and forests.......... 2-1 + Impacts to riparian and aquatic ecosystems.......................... 2-3 + Compatibility of social uses with LSR objectives................. 2-4 + Summary of Issues and Key Questions................................ 2-5 Chapter 3- Current Conditions in the Watershed .................... 3- I + Lack and loss of late-successional forests............................ 3- 1 • Composition and structure of vegetative communities 3- 1 Map 6. Forest Canopy Cover Map 7. Vegetation Types • Fragmentation of late-successional forest................... 3- 3 • Fuels and fire hazard conditions within late-successional forests ........ ~................................... 3- 3 • Terrestrial S&M species habitat.. ..... ~........................ 3- 5 Map 8. Live Fuel Hazard Map 9. Dead and Down Fuel Loading Map 10. Late-Successional Forest &·Fire Hazard : '.·· ~ -­ • TES species within the watershed .... ~ ........ ;...... :..... ~~ ... ~ , 3-7 . ··· ...: . ... - . ; ·~· Table of Contents Chapter 3- Current Conditions in the Watershed ............ (continued) + Impacts to riparian and aquatic ecosystems ............... :........ 3-12 • Current conditions that adversely affect aquatic habitat and riparian ecosystems................... 3-12 Map 11. Riparian Reserves • Current transportation system within the watershed.. 3-15 • Habitat for Survey and Manage and riparian associated species that occupy riparian ecosystems .. 3-15 + Compatibility of social uses with LSR objectives .............. 3-19 • Commodities being produced .................................. 3-20 • Natural trout production and present fish stocking levels.......................................................... 3-20 • Compatibility of recreation use with LSR objectives.· 3-20 Chapter 4- Reference Conditions within the Watershed...... 4- 1 + Lack and loss of late-successional forests ...... :................... 4- 1 • Composition and structure of vegetative communities .4- 1 • Late-successional and old~growth forest habitat....... 4- 4 • Fuels/fire conditions within the watershed................ 4- 6 • Impacts to riparian and aquatic ecosystems........................ 4- 7 • Riparian and aquatic ecosystems.............................. 4- 7 • Hydrologic reference conditions................................ 4- 9 • Soil stability and geologic processes........................ 4-11 + Transportation system within the watershed............. 4-11 + Compatibility of social uses with LSR objectives............... 4-13 • Commodities being produced ......... .-......................... 4-13 • Natural trout production and present fish stocking levels................................................... 4-14 • Compatibility of recreational use with LSR objectives 4-14 Chapter 5- Interpretations ................................. ~················· 5- 1 + Lack and loss of late-successional forests.......................... 5- 1 . • Heavy dead and down fuel loading ............ ~ .. ;.......... 5-2 • ·Dense understory conditions ........... ;... ~ .............. ~..... 5- 3 • Potential for fire occurrence ............... ·.. :......... ~......... 5- 4 • · Lack of old-growth and late-successional :forests .. .' .... , .5- .5 . • Species composition of mixed conifer stands .. ~......... 5-6 -·-~ ·-.··· Table of Contents Chapter 5- Interpretations .................................................... (continued) + Lack and loss of late-successional forests ..................... (continued) • Limited presence of large diameter ponderosa pines 5- 7 • Fragmentation of late-successional stands................ 5- 8 + Impacts to riparian and aquatic ecosystems........................ 5-9 • Degradation and loss of aquatic habitat.................... 5- 9 • Current road density ....... ~........................................ 5-11 • S&M and riparian obligate habitat........................... 5-12 + Compatibility of social u·ses with LSR objectives.............. 5-13 • Firewood cutting .................................... :............... ; 5-13 • Off-road vehicle use................................................ 5-14. • Fishing activities...................................................... 5--15 Chapter 6- Recommendations................................................. 6- 1 + Emphasis Areas Map 12. Emphasis Areas • Emphasis Area 1 - Lower Basin............................ .. 6-2 • Emphasis Area 2 - Ridgetop ................................. .. 6-3 • Emphasis Area 3- Midslopes ............ ~·~ ................. .. 6-3 • Emphasis Area 4 - Deferred Areas ....................... .. 6-4 + Recommendations • Protection ofLSR from Loss to Wildfire .............. .. 6-5 • Condition of Late-successional Forests: ................. 6-6 • Bald Eagle Habitat.. ............................................. .. 6-7 • Road Management. ................................................. 6-8 • Riparian Management. ......................................... ;. 6-10 • Woodcutting Management.. .................................. 6-11 • Fishing Access to Iron Canyon Reservoir ............. .. 6-12 • Recreational Fishing.............................................. 6-12 + Surveying and Monitoring Needs .................................... .. 6-13 + Prioritization of Recommendations ......................... :........ 6-14 .. \ .•··· ·-: . 3/26/96 Draft Iron Canyon ·watershed Analysis page 3 · ..:.:-,-_-·:.-- Table of Contents Appendix A- Possible Management Practices Appendix B- Hydrology Input Appendix C- List of Wildlife Species Appendix D- Threatened, Endangered and Sensitive Species Analysis Abbreviations and Glossary 5/8/96 Iron Canyon Watershed Analysis page 4 Chapter 1: Characterization of the Watershed Chapter 1 Characterization of the Iron Canyon Watershed Area The purpose of this chapter is to place the watershed in context within the river basin, provinces, and the broad geographic area. This chapter will briefly analyze the dominant physical, biological, and human dimension features, characteristics, and uses of the watershed. The Iron Canyon Watershed is located near the small town of Big Bend, within Shasta County, ·California. The watershed lies about 26 ;miles north and east of the larger regional center Redding, and is a component of the Pit River Drainage (see "Vicinity map, (Map 1)). The watershed is about 17,000 acres in size, of which 12,300 acres are National Forest (see ''Private Ownership" map, (Map 3)). The Iron Canyon Watershed is entirely within the boundary of the Shasta-Trinity National Forests. The watershed is a component of Management Area 11 in the Forest Land Management Plan (LMP), and also compri~es the eastern l/6th of Late Successional
Load more

Recommended publications
  • Menindee Lakes, the Lower Darling River and Darling Anabranch)
    THE LIVING MURRAY Information Paper No. 10 IPTLM0010 Health of the River Murray Menindee Lakes, the Lower Darling River and Darling Anabranch) Contents Environmental assets within the river zone Current condition of environmental assets Reasons why some environmental assets have declined in value What can be done to restore environmental values? Existing environmental flows initiatives The system-wide perspective References Introductory Note Please note: The contents of this publication do not purport to represent the position of the Murray-Darling Basin Commission. The intention of this paper is to inform discussion for the improvement of the management of the Basin’s natural resources. 2 Environmental assets within the river zone The lower Darling River system is located at the downstream end of the River Murray system in NSW and is marked by Wentworth to the south and Menindee to the north. It encompasses the Menindee Lakes system, the Darling River below Menindee and the Great Anabranch of the Darling River (referred to hereafter as the Darling Anabranch) and associated lakes. These are iconic riverine and lake systems within the Murray-Darling Basin. In addition, a vital tributary and operating system feeds the lower River Murray. The climate of the area is semi-arid with an annual average rainfall of 200 mm at Menindee (Auld and Denham 2001) and a high potential annual evaporation of 2,335 mm (Westbrooke et al. 2001). It is hot in summer (5–46oC) and mild to cold in winter (-5–26oC). In particular, the lower Darling River system is characterised by clusters of large floodplain lakes, 103 to 15,900 ha in size, located at Menindee and along the Darling Anabranch.
    [Show full text]
  • Understanding the Temporal Dynamics of the Wandering Renous River, New Brunswick, Canada
    Earth Surface Processes and Landforms EarthTemporal Surf. dynamicsProcess. Landforms of a wandering 30, 1227–1250 river (2005) 1227 Published online 23 June 2005 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/esp.1196 Understanding the temporal dynamics of the wandering Renous River, New Brunswick, Canada Leif M. Burge1* and Michel F. Lapointe2 1 Department of Geography and Program in Planning, University of Toronto, 100 St. George Street, Toronto, Ontario, M5S 3G3, Canada 2 Department of Geography McGill University, 805 Sherbrooke Street West, Montreal, Quebec, H3A 2K6, Canada *Correspondence to: L. M. Burge, Abstract Department of Geography and Program in Planning, University Wandering rivers are composed of individual anabranches surrounding semi-permanent of Toronto, 100 St. George St., islands, linked by single channel reaches. Wandering rivers are important because they Toronto, M5S 3G3, Canada. provide habitat complexity for aquatic organisms, including salmonids. An anabranch cycle E-mail: [email protected] model was developed from previous literature and field observations to illustrate how anabranches within the wandering pattern change from single to multiple channels and vice versa over a number of decades. The model was used to investigate the temporal dynamics of a wandering river through historical case studies and channel characteristics from field data. The wandering Renous River, New Brunswick, was mapped from aerial photographs (1945, 1965, 1983 and 1999) to determine river pattern statistics and for historical analysis of case studies. Five case studies consisting of a stable single channel, newly formed anabranches, anabranches gaining stability following creation, stable anabranches, and an abandoning anabranch were investigated in detail.
    [Show full text]
  • The Form of a Channel
    23 GEOMORPHOLOGY 201 READER The bankfull discharge is that flow at which the channel is completely filled. Wide variations are seen in the frequency with which the bankfull discharge occurs, although it generally has a return period of one to two years for many stable alluvial rivers. The geomorphological work carried out by a given flow depends not only on its size but also on its frequency of occurrence over a given period of time. The flow in river channels exerts hydraulic forces on the boundary (bed and banks). An important balance exists between the erosive force of the flow (driving force) and the resistance of the boundary to erosion (resisting force). This determines the ability of a river to adjust and modify the morphology of its channel. One of the main factors influencing the erosive power of a given flow is its discharge: the volume of flow passing through a given cross-section in a given time. Discharge varies both spatially and temporally in natural river channels, changing in a downstream direction and fluctuating over time in response to inputs of precipitation. Characteristics of the flow regime of a river include seasonal variations in discharge, the size and frequency of floods and frequency and duration of droughts. The characteristics of the flow regime are determined not only by the climate but also by the physical and land use characteristics of the drainage basin. Valley setting Channel processes are driven by flow and sediment supply, although the range of channel adjustments that are possible are often restricted by the valley setting.
    [Show full text]
  • Historical Channel Adjustment and Estimates of Selected Hydraulic Values in the Lower Sabine River and Lower Brazos River Basins, Texas and Louisiana
    Historical Channel Adjustment and Estimates of Selected Hydraulic Values in the Lower Sabine River and Lower Brazos River Basins, Texas and Louisiana By Franklin T. Heitmuller and Lauren E. Greene In cooperation with the Texas Water Development Board Scientific Investigations Report 2009–5174 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior KEN SALAZAR, Secretary U.S. Geological Survey Suzette M. Kimball, Acting Director U.S. Geological Survey, Reston, Virginia: 2009 This and other USGS information products are available at http://store.usgs.gov/ U.S. Geological Survey Box 25286, Denver Federal Center Denver, CO 80225 To learn about the USGS and its information products visit http://www.usgs.gov/ 1-888-ASK-USGS Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. Suggested citation: Heitmuller, F.T., and Greene, L.E., 2009, Historical channel adjustment and estimates of selected hydraulic values in the lower Sabine River and lower Brazos River Basins, Texas and Louisiana: U.S. Geological Survey Scientific Investigations Report 2009–5174, 143 p. iii Contents Abstract ..........................................................................................................................................................1 Introduction ....................................................................................................................................................1
    [Show full text]
  • Understanding Braided River Landform Development Over Decadal Time Scale: Soil and Groundwater As Controls on Biogeomorphic Succession
    Unicentre CH-1015 Lausanne http://serval.unil.ch RYear : 2016 Understanding braided river landform development over decadal time scale: soil and groundwater as controls on biogeomorphic succession. Bätz Nico Bätz Nico, 2016, Understanding braided river landform development over decadal time scale: soil and groundwater as controls on biogeomorphic succession. Originally published at : Thesis, University of Lausanne Posted at the University of Lausanne Open Archive http://serval.unil.ch Document URN : urn:nbn:ch:serval-BIB_CB468C1D42D59 Droits d’auteur L'Université de Lausanne attire expressément l'attention des utilisateurs sur le fait que tous les documents publiés dans l'Archive SERVAL sont protégés par le droit d'auteur, conformément à la loi fédérale sur le droit d'auteur et les droits voisins (LDA). A ce titre, il est indispensable d'obtenir le consentement préalable de l'auteur et/ou de l’éditeur avant toute utilisation d'une oeuvre ou d'une partie d'une oeuvre ne relevant pas d'une utilisation à des fins personnelles au sens de la LDA (art. 19, al. 1 lettre a). A défaut, tout contrevenant s'expose aux sanctions prévues par cette loi. Nous déclinons toute responsabilité en la matière. Copyright The University of Lausanne expressly draws the attention of users to the fact that all documents published in the SERVAL Archive are protected by copyright in accordance with federal law on copyright and similar rights (LDA). Accordingly it is indispensable to obtain prior consent from the author and/or publisher before any use of a work or part of a work for purposes other than personal use within the meaning of LDA (art.
    [Show full text]
  • Map-Based Tests on Controls of Anabranch River Character On
    MAP-BASED TESTS ON CONTROLS OF ANABRANCH RIVER CHARACTER ON THE LOWER YELLOWSTONE RIVER by Patricia Ann Jenkins A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Earth Sciences MONTANA STATE UNIVERSITY Bozeman, Montana November 2007 © COPYRIGHT by Patricia Ann Jenkins 2007 All Rights Reserved - ii - APPROVAL of a thesis submitted by Patricia Ann Jenkins This thesis has been read by each member of the thesis committee and has been found to be satisfactory regarding content, English usage, format, citations, bibliographic style, and consistency, and is ready for submission to the Division of Graduate Education. Dr. Stephan G. Custer Approved for the Department of Earth Sciences Dr. Stephan G. Custer Approved for the Division of Graduate Education Dr. Carl A. Fox - iii - STATEMENT OF PERMISSION TO USE In presenting this thesis in partial fulfillment of the requirements for a master’s degree at Montana State University, I agree that the library shall make it available to borrowers under rules of the library. If I have indicated my intention to copyright this thesis paper by including a copyright notice page, copying is allowable only for scholarly purposes, consistent with “fair use” as prescribed by the U.S. Copyright Law. Requests for permission for extended quotation from or reproduction of this thesis in whole or parts may be granted only by the copyright holder. Patricia Ann Jenkins November 2007 - iv - ACKNOWLEDGMENTS I wish to thank my main advisor, Dr. Stephan Custer, for his perpetual enthusiasm and encouragement. I also wish to express appreciation for my committee members, Dr.
    [Show full text]
  • Morpho-Sedimentary Characteristics of Proximal Gravel Braided River Deposits in a Froude-Scaled Physical Model Peter Ashmore [email protected]
    Western University Scholarship@Western Geography Publications Geography Department 2017 Morpho-sedimentary characteristics of proximal gravel braided river deposits in a Froude-scaled physical model Peter Ashmore [email protected] Tobias Gardner Pauline Leduc Follow this and additional works at: https://ir.lib.uwo.ca/geographypub Part of the Geomorphology Commons, Physical and Environmental Geography Commons, and the Sedimentology Commons Citation of this paper: Ashmore, Peter; Gardner, Tobias; and Leduc, Pauline, "Morpho-sedimentary characteristics of proximal gravel braided river deposits in a Froude-scaled physical model" (2017). Geography Publications. 357. https://ir.lib.uwo.ca/geographypub/357 DR. TOBI GARDNER (Orcid ID : 0000-0002-9434-3420) Article type : Original Manuscript Corresponding author mail id:- [email protected] Morpho-sedimentary characteristics of proximal gravel braided river deposits in a Froude-scaled physical model Tobi Gardner1, Peter Ashmore, and Pauline Leduc Department of Geography, Western University, London, Ontario, Canada 1Now at Capital Region District, Victoria BC Canada Associate Editor – Vern Manville Short Title – Morpho-sedimentary of proximal braided river deposits ABSTRACT A Froude-scaled physical model of a proximal gravel-bed braided river was used to connect the river morphological characteristics, and sedimentary processes and forms, to deposit geometry. High resolution continuous three-dimensional topographic data was acquired from sequential photogrammetric digital elevation models paired
    [Show full text]
  • Controls on Anastomosis in Lowland River Systems: Towards Process-Based Solutions to 2 Habitat Conservation
    1 Controls on anastomosis in lowland river systems: towards process-based solutions to 2 habitat conservation 3 Paweł Marcinkowski1, Robert C. Grabowski2*, Tomasz Okruszko1 4 1Department of Water Engineering, Faculty of Civil and Environmental Engineering, Warsaw University of Life 5 Sciences (WULS-SGGW), Nowoursynowska 159 street, 02-776 Warszawa, Poland, e-mail: 6 [email protected], [email protected] 7 2 School of Water, Energy, and Environment. Cranfield University, College Road, Cranfield, Bedfordshire, MK43 8 0AL, UK. 9 10 * Corresponding author: [email protected] 11 This is the authors’ manuscript. The final article is available from Science of the Total 12 Environment. 13 Abstract 14 Anastomosing rivers were historically common around the world before extensive agricultural and industrial 15 development in river valleys. Few lowland anastomosing rivers remain in temperate zones, and the protection of 16 these river-floodplain systems is an international conservation priority. However, the mechanisms that drive the 17 creation and maintenance of multiple channels, i.e. anabranches, are not well understood, particularly for lowland 18 rivers, making it challenging to identify effective management strategies. This study uses a novel multi-scale, 19 process-based hydro-geomorphological approach to investigate the natural and anthropogenic controls on 20 anastomosis in lowland river reaches. Using a wide range of data (hydrologic, cartographic, remote-sensing, 21 historical), the study (i) quantifies changes in the planform of the River Narew, Poland over the last 100 years, (ii) 22 documents changes in the natural and anthropogenic factors that could be driving the geomorphic change, and (iii) 23 develops a conceptual model of the controls of anastomosis.
    [Show full text]
  • Decimeterscale in Situ Mapping of Modern Crossbedded Dune
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CONICET Digital GEOPHYSICAL RESEARCH LETTERS, VOL. 40, 1–5, doi:10.1002/grl.50703, 2013 Decimeter-scale in situ mapping of modern cross-bedded dune deposits using parametric echo sounding: A new method for linking river processes and their deposits Gregory H. Sambrook Smith,1 James L. Best,2 Oscar Orfeo,3 Mark E. Vardy,4 and Jessica A. Zinger5 Received 10 May 2013; revised 27 June 2013; accepted 27 June 2013. [1] Collecting high-resolution data to quantify the of the structure of alluvial successions derived from study of sedimentary architecture within contemporary alluvial contemporary river channels. In the last 15 years, ground channels remains one of the outstanding challenges in fluvial penetrating radar (GPR) has revolutionized quantification sedimentology. Here, we present data collected using a new of the subsurface sedimentary architecture of modern alluvial geophysical method, the parametric echo sounder (PES), sediments [Bridge et al., 1998; Fielding et al., 1999; Best which can meet this challenge. From surveys over a field of et al., 2003; Wooldridge and Hickin, 2005; Mumpy et al., sand dunes in the Río Paraná, Argentina, we demonstrate the 2007; Sambrook Smith et al., 2006, 2009] and has resulted unique ability of PES to image the subsurface structure in new models of alluvial heterogeneity. However, GPR is within active channels at a decimetric resolution. These data often restricted to deployment on exposed bar surfaces and, reveal the bounding surfaces between bars and dunes, as if used through the water column, often provides data with well as the foresets and reactivation surfaces within them.
    [Show full text]
  • The Why, When, and Where of Anabranching Rivers in the Arid Lake Eyre Basin Sarah Victoria Eccleshall University of Wollongong
    University of Wollongong Research Online University of Wollongong Thesis Collection 2017+ University of Wollongong Thesis Collections 2019 The why, when, and where of anabranching rivers in the arid Lake Eyre Basin Sarah Victoria Eccleshall University of Wollongong Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong. Recommended Citation Eccleshall, Sarah Victoria, The why, when, and where of anabranching rivers in the arid Lake Eyre Basin, Doctor of Philosophy thesis, School of Earth and Environmental Sciences, University of Wollongong, 2019. https://ro.uow.edu.au/theses1/554 Research Online is the open access institutional repository for the University of Wollongong. For further information contact the UOW Library: [email protected] School of Earth and Environmental Sciences Faculty of Science, Medicine and Health The why, when, and where of anabranching rivers in the arid Lake Eyre Basin Sarah Victoria Eccleshall BSc (Hons.) University of Wales, Aberystwyth; MSc Stockholm University This thesis is presented as a requirement for the conferral of the degree: Doctor of Philosophy of the University of Wollongong June 2019 ii Abstract Multi-channel or anabranching planforms are a common river planform found in arid regions and nowhere is this more prevalent than in the 1.14 M km2 endorheic Lake Eyre Basin (LEB) of arid Australia. Of the19 main rivers in this basin, 14 anabranch for large proportions of their length yet with different multi-channel planform styles occurring in different parts of the basin. This thesis has three primary aims.
    [Show full text]
  • Why Some Alluvial Rivers Develop an Anabranching Pattern
    University of Wollongong Research Online Faculty of Science - Papers (Archive) Faculty of Science, Medicine and Health 2007 Why some alluvial rivers develop an anabranching pattern He Qing Huang Chinese Academy Of Sciences Gerald C. Nanson University of Wollongong, [email protected] Follow this and additional works at: https://ro.uow.edu.au/scipapers Part of the Life Sciences Commons, Physical Sciences and Mathematics Commons, and the Social and Behavioral Sciences Commons Recommended Citation Huang, He Qing and Nanson, Gerald C.: Why some alluvial rivers develop an anabranching pattern 2007, 1-12. https://ro.uow.edu.au/scipapers/3136 Research Online is the open access institutional repository for the University of Wollongong. For further information contact the UOW Library: [email protected] Why some alluvial rivers develop an anabranching pattern Abstract Anabranching rivers have been identified globally, but a widely accepted and convincing theoretical explanation for their occurrence has remained elusive. Using basic flow and sediment transport relations, this study analyzes the mechanisms whereby self-adjusting alluvial channels can anabranch to alter their flow efficiency (sedimentanspor tr t capacity per unit of stream power). It shows that without adjusting channel slope, an increase in the number of channels can produce a proportional decrease in flow efficiency, a finding particularly relevant to understanding energy consumption in some braided rivers. However, anabranching efficiency can be significantly increased by a reduction in channel width, as occurs when vegetated alluvial islands or between-channel ridges form. The counteracting effects of width reduction and an increasing number of channels can cause, with no adjustment to slope, an otherwise unstable system (underloaded or overloaded) to achieve stability.
    [Show full text]
  • Dynamics of Nonmigrating Mid-Channel Bar and Superimposed Dunes in a Sandy-Gravelly River (Loire River, France)
    Geomorphology 248 (2015) 185–204 Contents lists available at ScienceDirect Geomorphology journal homepage: www.elsevier.com/locate/geomorph Dynamics of nonmigrating mid-channel bar and superimposed dunes in a sandy-gravelly river (Loire River, France) Coraline L. Wintenberger a, Stéphane Rodrigues a,⁎, Nicolas Claude b, Philippe Jugé c, Jean-Gabriel Bréhéret a, Marc Villar d a Université François Rabelais de Tours, E.A. 6293 GéHCO, GéoHydrosystèmes Continentaux, Faculté des Sciences et Techniques, Parc de Grandmont, 37200 Tours, France b Université Paris-Est, Laboratoire d'hydraulique Saint-Venant, ENPC, EDF R&D, CETMEF, 78 400 Chatou, France c Université François Rabelais — Tours, CETU ELMIS, 11 quai Danton, 37 500 Chinon, France d INRA, UR 0588, Amélioration, Génétique et Physiologie Forestières, 2163 Avenue de la Pomme de Pin, CS 40001 Ardon, 45075 Orléans Cedex 2, France article info abstract Article history: A field study was carried out to investigate the dynamics during floods of a nonmigrating, mid-channel bar of the Received 11 February 2015 Loire River (France) forced by a riffle and renewed by fluvial management works. Interactions between the bar Received in revised form 17 July 2015 and superimposed dunes developed from an initial flat bed were analyzed during floods using frequent mono- Accepted 18 July 2015 and multibeam echosoundings, Acoustic Doppler Profiler measurements, and sediment grain-size analysis. Available online 4 August 2015 When water left the bar, terrestrial laser scanning and sediment sampling documented the effect of post-flood sediment reworking. Keywords: fl fi Sandy-gravelly rivers During oods a signi cant bar front elongation, spreading (on margins), and swelling was shown, whereas a sta- Nonmigrating (forced) bar ble area (no significant changes) was present close to the riffle.
    [Show full text]