London, Ontario November, 1998
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MORPHOLOGY OF THREE SEM-ALLUVIAL STREAM CHANNELS IN SOUTHERN ONTARIO by Giflian E. Foster Department of Geography Submitted in partial fblfiIIment of the requirements of the degree of Master of Science Faculty of Graduate Studies The University of Western Ontario London, Ontario November, 1998 O Gillian E. Foster 1998 National Library Bibliothèque nationale 1+1 of,", du Canada Acquisitions and Acquisitions et Bibliographic Services services bibliographiques 395 Wellington Street 395. nie Wellington Ottawa ON K1A ON4 Ottawa ON KIA ON4 Canada Canada Your t% Votre refër~nte Our Ne Notre retéfence The author has granted a non- L'auteur a accordé une licence non exclusive licence allowing the exclusive permettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, loan, distribute or sell reproduire, prêter, distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la fome de microfiche/fïlm, de reproduction sur papier ou sur format électronique. The author retains ownersbip of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantid extracts from it Ni la thèse ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation. Stream in southwestern Ontario are commonly incised into a variety of erodible glacial matenals, ranging fiom cohesive clay to boulders, which they often lack competence to transport. Detailed longitudinal profiles surveyed along three such 'semi- alluvial' channels (Dingrnan, Oxbow and Nissouri Creeks) indicate that pool-riffle spacing is short, irregular and morphology is poorly developed. Common features include a disordered bed material sequence, deep sculpted till-lined pools, multiple riffies, over-widened bends and till ledges. Stream rehabilitation is ofien based on simple assumptions of alluvial chamel characteristics, such as a mean pool-nffle spacing of five to seven times the channel width. Various techniques for defining bedforrn spacing are invest igat ed. Spacing is found to be sensitive to its definition, frequency distributions are positively skewed and both mode and mean spacings are less than 5-7 widths. Natural Channel Design and habitat restoration therefore needs to incorporate differences in pool-rime features that exist in semi-alluvial streams. Keywords: Pool, Riffle, Bedform, Semi-Alluvial, Fluvial Geomorphology, Dingman Creek, Oxbow Creek, Nissourî Creek, Natural Channel Design 1 wish to thank my advisor, Dr. Peter Ashrnore, without whom this thesis couid not have corne to hition. His hom of counseling and generous financial support through an N.S.E.R.C. operating gant are much appreciated. Thanks are also owed to Bill Snodgrass. the Credit Valley Conservation Authority and the Ontario Ministry of Naturd Resources for mermonetary suppon during the field season. Thanks to Rick GoIdt of the Upper Thames River Conserva~ionAuthority, who provided documentation about the study area. I greatly appreciate the CO-operationof the local residents who gave permission to be on their land and who supplied information about the creeks and area. Thank you to the many and varied field assistants; Barb for wanting to get started yesterday, Matt for not ietting go of that tree û-unk when up to his chin in water, Alex for helping when he didn't have to, for being patient and for swiving my stress. Peggy and Serge ("lovely"), Rob for taking a break fiom tree rings to try out rivers for a day. the various animals that tagged dong and provided amusement (Casey the dog. the bat. and the bu11 that came a bit too close), but most of alI, thanks to Heather for stepping in when al1 seemed lost, for her dedication, patience. ceaseless enthusiasm. amazingly neat field notes, hilarious sketches and for acquainting the crayfish with Skittles. Thanks tu Fred. without whose encyclopedic knowledge of computer software. surveying savvy and patient teaching 1would be tnily lost. Thank you to my parents, who (when they werenotgetting married or Ieaving the country) were always there for me - my mother's leîters are always something to look forward to. nianks to my brother for supplying me with 'real' music and for being rq7 confidant across the miles - I'm proud of you Nick. Thanks to the gang who are still going through this emotional roller-coaster that is grad school, and to those who have already made it out the other end: to Emma (when she was actually around) and Gary for Chapters trips and for keeping me domto earth. to Bonnie for cleaning (repeatedly) around my jungle of plants and for sharing her mother's lemon loaf, to LeeAnn for teaching me not to 'cave', to Rob for providing amusement and fixing my computer, and Andrea for always smiling, to Rich - someone who also understands why rivers are exciting, to Steve and Stacey (good luck you two), to Tmdy or Strudel (guac queen and taxi extraordinaire), and to Scott for not succeeding in his efforts to bring Star Wars into my life. Thanks also to Trish and Dave for knowing that real coffee cornes hmout west, to Melissa, Cheryl, Jen, Kumari, Came, Dendro Don (OK, ifs not a purse), Connie, Dan, Evan, and Ethan (for giving up his room). And finally, thanks to Pepper, my cat- for comforting me and easing the stress - and for only putting me in hospital the one time.. I wouid like to dedicate this thesis to my grandmother, Marie Foster. who passed away before 1 could make her really proud. Ho- GidL TABLE OF CONTENTS Page. CERTIFICATE OF EXAMINATION ................................................... 11 ... ABSTRACT ....................................................................................... 111 ACKNO WLEDGEMENTS ..................................................................... iv TABLE OF CONTENTS ..................................................................... vi LIST OF TABLES .............................................................................. x LIST OF FIGURES ............................................................................. .xi LIST OF APPENDICES ...................... .. ............................................ xlv CfFAPTER 1. Introduction ............................................................ 1 1.1 General introduction ................................ ..,, ......,, 1 1.2 Pools and riffles and chamel restoration ............................... -2 1.3 Research objectives ........................................................... -4 1.4 Framework of the study ................................................... 4 CHAPTER II .Pools and rimes: tbeir form. definition. and signifieance ............ 6 2.1 Characteristics of the ideal pool-riffle sequence in regularly meandering alluvial rivers ................................. 6 2.1.1 Pook .................................................................... 6 2.1.2 Riffles ..................................................................... 7 2.1 -3 Pools and riffles ................................................... 8 2.1.4 Meanders and the pool-riffle sequence ....................... -9 2.2 Problems associated with pool-rime identification ....................... 10 2.2.1 Definition of the pool-rime sequence ....................... 10 2.2.2 Field identification of pools and riffles ....................... 13 2.3 Pool-riffle spacing ........................ .... .......................... 14 2.3.1 Deviations from the ideal pool-riffle pattern ...................... -16 2.3.1.1 Irregular planform ..................... ... .............. 16 2.3.1 -2Local sediment supply ................................ 17 2.3.1.3 Forced pool-riffle morphologies ...................... -18 2.3.1.4 Streams in bedrock ......................................... 18 2.3-2 Standardkation by channel width ................................ 19 2.4 Influence of glacial material on pool-rifle sequences in southem Ontario .......................................................... -20 CHAPTER III .Study area and research methods ................................ 24 3.1 Physical characteristics of the mdy area ............................... -24 3.2.1 Geology and Geomorphology ......................................... 24 3.1 -2 Soils and vegetation ................................................. -25 3.1.3 Ciimate .......................................................... -26 3 -2 Site selection ................................................................... -26 3 -3 Study site description .......................................................... 29 3 .3.1 Dingman Creek .................................................. 31 3 .3.2 Oxbow Creek .......................................................... -34 3 .3.3 Nissouri Creek .................................................. 36 3 -4 Field techniques ........................................................... 38 3.4.1 Bed profile and planform survey ................................ 38 3.4.2 Bathymetricsurvey ................................................. 41 3 -5 Data preparation and analysis ............................................... 41 3.5.1 Channel planform ................................................. -42 3.5.2 Bedprofile ..................... ... ............................... 42 3.5.2.1 Pool-riffle definition problem ....................... 42 3 S.2.2 Field identification of bedforms in test reach .....43 3.5.2.3 Visual inspection of test