This study investigates changes to channel morphology along Chilliwack River in southwest British Columbia, and relates these changes to the transport of bed material. The channel was mapped using a stereoplotter from a sequence of historical aerial photography between 1952 and 1991. Maps for selected years were overlaid, then analyzed with a GIS. Erosion and deposition volumes of bed material were determined by multiplying measured planimetric changes by the varying depth of bed material along the river. A sediment budget framework was used to estimate bed material transport rates from these net changes in stored sediment volumes. The transport rate of bed material for Chilliwack River is estimated as 55,000±10,000 m3/yr for the period 1983 to 1991. Instability along lower channel reaches has increased over the 40 year period of study due to an increase in both the magnitude and frequency of large floods. As a consequence, channel width, bank erosion rates and the volume of sediment transported past Vedder Crossing became increasingly large. Between 1952 and 1975, Chilliwack River was in a transient state of equilibrium as the channel continued to recover from a sequence of large floods in previous decades. Large floods in 1975 and 1980 caused significant bank erosion along lower reaches, which increased the amount of sediment available for transport. Extreme floods in 1989 and 1990 caused further erosion, and in fact, were large enough to alter the pre-flood channel regime. However, in the absence of further large floods, the channel should recover from these events in 10 to 20 years. Significant morphologic change on Chilliwack River occurs roughly once every 5 years, when peak flows exceed 500 m3/s. These floods are sufficient to erode channel banks, where the dominant supply of mobile bed material is stored. Aggradation occurs in the short term as more sediment is introduced to the active channel zone than can be removed by subsequent smaller flows. However, as flows as small as 250 m3/s (which occur several times per year, on average) are capable of mobilizing bed material, there is net degradation over the longer term. As the length between survey dates used in this study averaged 10 years, some information on bed material transport between dates is lost. Nonetheless, this study has demonstrated that considerable information on historic channel change can be obtained form aerial photographs.

This study investigates changes to channel morphology along Chilliwack River in southwest British Columbia, and relates these changes to the transport of bed material. The channel was mapped using a stereoplotter from a sequence of historical aerial photography between 1952 and 1991. Maps for selected years were overlaid, then analyzed with a GIS. Erosion and deposition volumes of bed material were determined by multiplying measured planimetric changes by the varying depth of bed material along the river. A sediment budget framework was used to estimate bed material transport rates from these net changes in stored sediment volumes. The transport rate of bed material for Chilliwack River is estimated as 55,000±10,000 m3/yr for the period 1983 to 1991. Instability along lower channel reaches has increased over the 40 year period of study due to an increase in both the magnitude and frequency of large floods. As a consequence, channel width, bank erosion rates and the volume of sediment transported past Vedder Crossing became increasingly large. Between 1952 and 1975, Chilliwack River was in a transient state of equilibrium as the channel continued to recover from a sequence of large floods in previous decades. Large floods in 1975 and 1980 caused significant bank erosion along lower reaches, which increased the amount of sediment available for transport. Extreme floods in 1989 and 1990 caused further erosion, and in fact, were large enough to alter the pre-flood channel regime. However, in the absence of further large floods, the channel should recover from these events in 10 to 20 years. Significant morphologic change on Chilliwack River occurs roughly once every 5 years, when peak flows exceed 500 m3/s. These floods are sufficient to erode channel banks, where the dominant supply of mobile bed material is stored. Aggradation occurs in the short term as more sediment is introduced to the active channel zone than can be removed by subsequent smaller flows. However, as flows as small as 250 m3/s (which occur several times per year, on average) are capable of mobilizing bed material, there is net degradation over the longer term. As the length between survey dates used in this study averaged 10 years, some information on bed material transport between dates is lost. Nonetheless, this study has demonstrated that considerable information on historic channel change can be obtained form aerial photographs. / Arts, Faculty of / Geography, Department of / Graduate

In the attempt to formulate a statement of the Canadian land ethic (if that can even be accomplished), it was decided one area had to be focused upon — that landscape is the Chilliwack Valley. The description of the factors contributing to the historical layering (or continuum) of the valley has been organized into five chapters. The first chapter is an introduction to the required theory and methodology. Since this is the first attempt at an analysis of British Columbian environmental history (based on a geographically finite area), various approaches in understanding the processes of alteration and accumulation which were found helpful have been outlined. The theory found most useful suggests landscape can only be understood if the ideologies associated with spatial topics of wilderness, pastoral, and urbanism are examined. The second is an objective presentation of events which resulted in physical alteration of the valley from its primeval state to its recent urbanization. Seven chronological periods have been identified beginning with prehistory' s geomorphology, synecology and aboriginal culture, and ending with the period from post World War II to 1971. The text is supported by a series of ten maps. The third chapter outlines a theory of cultural diffusion which has determined the expectations of the various settlers to the valley. Due to the limited time and resources available, those aspects of world heritage which filtered to Chilliwack with the British received particular attention. This could be justified because by official, cultural, and individual influence, these concepts have set the matrix for what has occurred in the valley in the past few centuries. Contributions examined include the natural landscape, the village, and the garden city. Each was analyzed for origins, evolution, and dispersal to this continent (and eventually to Chilliwack). A model of idea diffusion has been abstracted to gain a more complete grasp of Canadian roots. The fourth is primary research into the modus operandi behind Chilliwackian landscape alteration. The values and ideals of successive generations of inhabitants have been discussed and their effect upon the land described. Human influence can be subdivided into four groupings including: Stalo responses to the indigenous landscape based upon a 10,000 year residency and a culture closely allied with nature; responses to the landscape by colonists who transferred an existing cultural infrastructure from Europe; responses influenced by contemporary environment solutions circulated throughout the world (both environmentally sensitive and solutions which disregard natural systems); and responses to the indigenous landscape by Chilliwackians, which reflect the emerging Canadian land ethic. The final chapter revolves around a discussion of Chilliwack's future. It offers a vision of what the future might be for coming generations if the trends indicated by both the legacy of the past and by new pressures facing the valley's limited space and resources are not controlled. Historical precedent for the land controls which offer the only hope for the valley is given. An analysis of the purpose and functioning of-the British Columbia Land Commission follows. In the summary, two observations are made. First, the Chilliwack Valley's mountainous containment coupled with the presence of an advanced civilization should result in the whole valley being regarded as a park for the benefit of both metro and valley residents. Its original perception as the "Garden of Eden" may yet be salvaged for future centuries to enjoy. The second observation is that a Canadian land ethic seems to be slowly emerging, which may come to rely upon Canadian imagery, both historical and natural, for design inspiration. / Applied Science, Faculty of / Architecture and Landscape Architecture (SALA), School of / Graduate

The stratigraphy and structure of Upper Palaeozoic and Mesozoic sedimentary and volcanic rocks, and of amphibolitic rocks of unknown age, were studied in an area of about 140 square miles in the Cascade Mountains of southwestern British Columbia. The amphibolitic rocks are probably of diverse origins; their stratigraphic relationship to the other rocks is not known, although they may, in part, be equivalent to pre-Devonian rocks in northwestern Washington. Upper Palaeozoic rocks comprise the Chilliwack Group. The base is not exposed. Oldest rocks are volcanic arenites and argillites which are overlain by an argillaceous limestone, about 100 feet thick, in which Early Pennsylvanian (Morrowan) fusulinids occur. Apparently conformably overlying the limestone is a succession of argillites, coarse volcanic arenites, minor conglomerate and local tuff, which contains both marine and terrestrial fossils and ranges in thickness from 450 to 800 feet. A cherty limestone, generally about 300 feet thick, in which there is an Early Permian (Leonardian) fusulinid fauna, is conformable upon the clastic sequence. Altered lavas and tuffs are in part laterally equivalent to this Permian limestone, and, in part, overlie it; these volcanic rocks range in thickness from 700 to 2,000 feet. Disconformably above the Permian volcanic rocks are argillites and volcanic arenites of the Cultus Formation. This formation is apparently about 4,000 feet thick, contains Late Triassic, Early and Late Jurassic fossils and no stratigraphic breaks have been recognized within it. All of these rocks underwent two phases of deformation between Late Jurassic and Miocene time. The first phase, correlated with mid-Cretaceous deformation in northwestern Washington, was the most severe., and thrusts and major, northeast-trending recumbent folds were formed. These structures subsequently were folded and faulted along a northwest trend, possibly in response to differential uplift of the Cascade Mountains. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Understanding how government's plan, make decisions and implement policy programmes is of vital concern to the planners who are expected to intervene in society's complex problems and formulate solutions that can be implement ed. A recent model examines political decision making processes and isolates four factors which influence decision outcomes: 1) the roles played by actors in the issue; 2) the nature of the decision making environment; 3) the characteristics of the issue; and 4) the type of planning and intervention strategies used. The model was used as a framework for examining a decision making episode in the District of Chilliwack, which centered around the issue of community growth in an area that had been circumscribed by the Agricultural Land Reserves. The model hypothesized that comprehensive, classical planning methods, which are goal-oriented and focus on long-term horizons, are likely to be rejected in decision making processes. This was confirmed in the Chilliwack case, along with the hypotheses that a proposal for change that is ideologically controversial, inflexible, and difficult to predict in its consequences, will likely be rejected. The fact that the Chilliwack plan was easy to programme and had a limited scope of costs and benefits could not overcome its drawbacks, therefore, these hypotheses were not upheld in the case study. The model's framework provided a useful means of examining and understanding why the particular outcome of the case study occurred. It clarified the inappropriatness of methods and means used by the Chilliwack decision makers and planners in attempting to achieve their goals. Consequently, the study points out that planners need new approaches, skills and knowledge in order to achieve socially acceptable and workable solutions to complex societal problems. / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate

The The’wá:lí Community Digital Mapping Project is a collaborative, scholarly project for which the final product is a digital, layered map of the reserve and traditional lands of the Stó:lō (Xwélmexw) community of The’wá:lí (Soowahlie First Nation). The map, containing over 110 sites and stretching from Bellingham Bay, Washington in the west to Chilliwack Lake, B.C. in the east, is hyperlinked with audio, visual and textual media that tell stories about places of importance to this community. The map is intended to give voice to many different senses of and claims to place, and their intersections, in the The’wá:lí environment, while also exploring the histories of how these places and their meanings have changed over time. It expresses many, often conflicting, ways of understanding the land and waterways in this environment, and presents an alternative to the popular, colonial narrative of the settlement of the Fraser Valley. Thus, the map, intended ultimately for The’wá:lí’s use, is also meant to engage a local, non-Indigenous audience, challenging them to rethink their perceptions about where they live and about the peoples with whom they share their histories and land. The essay that follows is a discussion of the relationship-building, research, writing and map-building processes that have produced the The’wá:lí Community Digital Map. / Graduate / 2017-08-21 / 0740 / 0509 / 0366 / sabinatrimble@gmail.com

Le continent nord-américain présente sur sa bordure Pacifique un domaine constitué par l'accrétion du Paléozoïque supérieur au Cénozoïque de fragments lithosphériques : les Cordillères nord-américaines. Ces fragments lithosphériques sont caractérisés par des séquences volcaniques d'arc ou de bassin océanique. Les séquences volcaniques d'arc du Paléozoïque supérieur et du Trias ont longtemps été considérées comme un seul arc. Depuis une dizaine d'années, des équipes françaises ont montré que les séquences d'arc du Paléozoïque et du Trias des Klamath orientales et de Sierra Nevada (Californie du Nord) étaient établies respectivement sur une lithosphère océanique et un bloc continental. Dans le Nevada occidental, les séquences d'arcs du Paléozoïque supérieur affleurent dans deux régions distinctes : Black Rock Desert et Excelsior Mountains. Dans le Black Rock Desert, la séquence permo-triasique de Bilk Creek ressemble en tout point à celle * des Klamath orientales et des Blue Mountains. Il s'agit d'un magmatisme d'arc permo-triasique continu, reposant sur des calcaires permiens inférieurs à affinité téthysienne. Ce magmatisme dériverait d'une source mantellique de type-MORB. Dans les Excelsior Mountains, la formation Black Dyke est constituée de laves et de pyroclastites recouvertes en concordance par des turbidites volcanoclastiques. Cette activité volcanique se produit au Permien inférieur autour de 276 Ma. Ce magmatisme d'arc présente de nombreuses similitudes avec celui de Sierra Nevada. Dans les deux cas, il s'agit d'un magmatisme exclusivement Permien, caractérisé par : (i) des roches volcaniques calco-alcalines; et (ii) de faibles valeurs d'eNd (T=275Ma) comprisent entre -11 et +5,5. Cet arc est séparé du continent nord-américain par un domaine océanique, le bassin de Golconda. En Sierra Nevada, cet arc paléozoïque est établi sur une séquence sédimentaire du Palézoïque inférieur tectonisée. Les faibles valeurs de l'eNd(T) des roches magmatiques de Sierra Nevada et des Excelsior Mountains suggèrent que les magmas dérivent d'une source mantellique, contaminée par une vieille croûte continentale, probablement protérozoïque. Ces magmas subissent au cours de leur remontée et leur stockage dans des chambres des assimilations de matériel crustal lors de leur fractionnement et de leur cristallisation. Le Paléozoïque supérieur volcanique et sédimentaire d'arc de Sierra Nevada et des Excelsior Mountains est plissé, puis recouvert en discordance par des sédiments respectivement du Trias ou du Jurassique. Ces déformations et cette discordance sont liées à la phase orogénique Sonoma, induite par la collision de cet arc avec la marge nord-américaine. Après l'accrétion de cet arc, un magmatisme calco-alcalin à shoshonitique se développe au Trias en bordure du craton. Sa diversité reflète vraisemblablement des variations dans la nature et l'épaisseur de de la croûte qui forme la marge occidentale cratonique américaine et sur laquelle s'édifie cet arc de type andin.