Channel adjustments and salmonid habitat alteration due to emergency dredging in Creighton Creek
department or school: Science, Irving K. Barber Faculty of (Okanagan)
department or school: Earth, Environmental and Geographic Sciences, Department of (Okanagan)
data provider: DSpace
degree campus: UBCO
creator: Hettrich, Lisa
issued: 2020-08-26T21:47:55Z
issued: 2020
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Creighton Creek, near Lumby, British Columbia, is a small, snow-melt driven, fish-bearing stream that has had its lower reaches confined due to agricultural, residential, and industrial development. Over the past four decades, the channel bed has aggraded and the channel geometry has become tortuous and multi-threaded causing habitat degradation and increased flood frequency. Therefore, in May 2017, emergency orders allowed instream dredging operations to take place without significant planning. The availability of pre-dredge data on channel characteristics provided a unique opportunity to quantify the geomorphic adjustments caused by the emergency dredging operations. An extensive field data set and hydraulic models were used to quantify the spatial and temporal changes within the study reach across three time periods including: (1) the 2015-2016 pre-treatment period; (2) the 2017 immediate post-treatment period; and (3) the 2018 recovery period, which includes the channel response after one freshet. During the 2018 freshet, large volumes of material infilled the dredged zone, returning the streambed to its initial grade. Study observations suggest that the stream was not supply-limited and that the material deposited in the dredged zone was from upstream sources. A reduction in sediment transport potential within the affected zone immediately after dredging was consistent with general coarsening of the stream bed substrate. After recovery, there was a degradation of salmonid habitat in the dredged zone because of grain-size coarsening. The research suggests that human modifications to stream channels should only be undertaken with full understanding of the broader (and long-term) geomorphic and hydrologic context of the reach. Emergency dredging operations, as occurred in Creighton Creek, may have relatively minor long-term impacts on stream characteristics as reflected in the longitudinal profile or in various average flow parameters. However, this is only the ca…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/75702
note: CHANNEL ADJUSTMENTS AND SALMONID HABITAT ALTERATION DUE TO EMERGENCY DREDGING IN CREIGHTON CREEK by Lisa Hettrich B.Sc., University of British Columbia, 2014 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE COLLEGE OF GRADUATE STUDIES (Earth, Environmental and Geographic Sciences) THE UNIVERSITY OF BRITISH COLUMBIA (Okanagan) September 2020 © Lisa Hettrich, 2020 The following individuals certify that they have read, and recommend to the College of Graduate Studies for acceptance, a thesis/dissertation entitled: Channel adjustments and salmonid habitat alteration due to emergency dredging in Creighton Creek submitted by Lisa Hettrich in partial fulfillment of the requirements of the degree of Master of Science. Dr. Bernard Bauer, Irving K Barber School of Arts and Sciences Supervisor Dr. Richard McCleary, Federal Department of Fisheries and Oceans Supervisory Committee Member Dr. Craig Nichol, Irving K Barber School of Arts and Sciences Supervisory Committee Member Dr. Nicholas Peleato, School of Engineering University Examiner ii Abstract Creighton Creek, near Lumby, British Columbia, is a small, snow-melt driven, fish-bearing stream that has had its lower reaches confined due to agricultural, residential, and industrial development. Over the past four decades, the channel bed has aggraded and the channel geometry has become tortuous and multi-threaded causing habitat degradation and increased flood frequency. Therefore, in May 2017, emergency orders allowed instream dredging operations to take place without significant planning. The availability of pre-dredge data on channel characteristics provided a unique opportunity to quantify the geomorphic adjustments caused by the emergency dredging operations. An extensive field data set and hydraulic models were used to quantify the spatial and temporal changes within the study reach across three time periods including: (1) the 2015-2016 pre-treatment period; (2) the…
has type: Thesis/Dissertation
date issued: 2020-09
is shown at: 10.14288/1.0392975
language: eng
degree discipline: Earth and Environmental Sciences
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/75702