Water Stewardship Information Sources

Citation Groulx, BJ, Mosher, DC, Lutnauer, JL and Bilderback, DE. 2004. Fraser River Delta, British Columbia: Issues of an Urban Estuary. Geological Survey of Canada. Bulletin 567.
Organization NRCAN
URL http://open.canada.ca/data/en/dataset/7af6c9af-abb5-540f-8863-59af303959d0
Abstract/Description or Keywords The papers in this bulletin derive from presentations made at a special session on issues of the Fraser River Estuary, part of a conference of the Pacific Section of the American Association for the Advancement of Science (AAAS). The special session was multidisciplinary in order to address the complexity of issues facing the Fraser River delta and estuary. The conference occurred in 1995; through a variety of circumstances, it has taken some time to produce this Bulletin. Although authors, as experts in their respective fields, may feel that the information they have presented is now dated, the issues remain relevant still. The papers in this volume are eclectic, to provide a sampling of issues surrounding the Fraser River delta. It is only through integrated scientific and social studies, such as those presented here, that we can minimize problems and maximize effective planning for stewardship and further development of the Fraser River delta. The editors would like to thank the authors for their patience in the production of this Bulletin. Humankind has been attracted to river deltas throughout history. They are rich, fertile, and productive regions for hunting, fishing, and harvesting. They are also amenable to the establishment of transportation corridors, whether on land or on water (river or ocean), and are highly suited to the establishment of villages, towns, and cities because of the flat and level landscape, loose soil conditions, and ready availability of construction material (e.g. wood and aggregate). River deltas are also highly productive areas for flora and fauna, and are very dynamic hydrological and geological environments. As a consequence of these factors, the river delta is a geographic location where humans interact with and impact the natural environment more than anywhere else. The Fraser River delta is certainly no exception. The Fraser River delta was a major centre of activity for First Nations people prior to the arrival of European settlers, and is now the focus of a population in excess of two million direct inhabitants, as well as a corridor of access to most of western Canada. In its short modern history, it has been affected dramatically by human activity. The focus of this volume is to discuss human impact on the Fraser River delta, and how the delta in turn impacts or has the potential to impact its human inhabitants. Paper summaries Geology and geography In order to contextualize the discussion of issues concerning the inhabitation of the Fraser River delta and its environs, it is necessary to understand the geological development and present geological setting of the area. Groulx and Mustard provide an insightful overview. The first-order control on the geography is tectonics. The area lies within a tectonically active region, with the Juan de Fuca oceanic plate converging with and subducting beneath the North American plate at this location. The resulting tectonic forces are responsible for the construction of the Coast Range Mountains, which provide source sediment for the Fraser River, and of the Georgia Basin, into which the Fraser River flows and deposits its sediment load, forming the Fraser River delta. The second-order control on the geographic setting is glaciation. The area has been covered with ice sheets numerous times over the last few million years; the latest was the Cordilleran Ice Sheet during the Fraser Stade glacial epoch, between 25 000 and 10 000 years ago. These glaciers are responsible for sculpting the landscape, giving rise to the steep-walled Fraser River valley, and depositing thick layers of sediment on the valley floor and walls. Fluvial processes resulting from the flow of the Fraser River exert the third and most direct form of control on the development of the delta. The high flow velocity, water volume, and sediment load of the Fraser River as it merges with the Strait of Georgia have resulted in the formation of the modern Fraser River delta, creating more than 625 km2 of new land within the Strait of Georgia in just the last 10 000 years. The same geological forces that created the Fraser River delta also present significant potential hazards. Damaging earthquakes can result from the tectonic setting, and the steep terrain and soft soil conditions can result in landsliding and soil liquefaction. Mosher, Christian, Hunter, and Luternauer discuss potential geohazards associated with the region's high seismicity, and present a review of modern techniques used to identify and assess these risks. Their geotechnical data, in association with analysis of ground-surface responses from recent earthquakes, suggest that the top 10 to 20 m of sediment over much of the delta, on- and offshore, are susceptible to seismic liquefaction - leading to possible flowsliding - in the event of a significant earthquake (M>5.0). The region, nonetheless, is becoming highly developed, as communities such as Richmond, Delta, and Ladner grow along with supporting infrastructures that include highways, railways, and port facilities, to say nothing of the industries that the delta supports (e.g. farming, fishing, aggregate mining). These significant hazards must be considered during further development of the Fraser River valley and delta. Geological knowledge, therefore, plays an important role and should be considered as the first step toward informed and effective land-use decisions. Kostaschuk and Luternauer address the issue of sedimentary processes in the river channels of the Fraser River estuary, and how they are linked to the transportation pathways of contaminants. In the main channel, sedimentary processes are controlled by river discharge and sediment load, by tidal conditions, and by the intrusion of salt water into the channel. During this past century, the river channels have been confined and therefore not allowed to migrate, as they are prone to do naturally. Sand is dredged from the river bed to maintain navigation channels and to supply construction aggregate. The effect of this containment and dredging is to channelize flow and confine sand movement to a narrow corridor, resulting in sediment deposition at the river mouth. This accumulation eventually fails through mass-transport processes, and slides down the foreslope of the delta into the deep water of the Strait of Georgia. Sand that once replenished sediment removed by coastal erosion of the tidal flats is now lost to deep water. This loss of sediment affects intertidal habitat and may increase slope erosion elsewhere on the delta. Wildlife habitat Adams and Williams, Harrison and Dunn, and Levings examine the impact of loss and protection of habitat on fauna in the Fraser River estuary. Many species use multiple habitats to complete their life cycle, making the definition of species-specific critical habitats exceedingly complex. Underscoring this complexity is an understanding that there currently is relatively little investment in research to document the dynamics of change in these biophysical regions. Other major estuaries on the west coast of North America have had the benefit of far more ecological research and monitoring. Subtidal, intertidal, and even agricultural areas sustain important habitat for fish and wildlife. Salinity and tidal inundation, related to the location of the salt wedge within the estuary, govern the distribution of plant species (and hence animal species) within these regions. Distinct salt-, brackish-, and freshwater species assemblages occur throughout the estuary as a result of these influences. In recent history, tidal regions have been subjected to sediment starvation and erosion through removal of sediment supply and construction of infrastructures on the tidal flats; intertidal regions have been modified through dyke construction; wetland areas in the Fraser Lowland have been reduced to about one quarter of their original extent in this past century through infilling and irrigation; and farmland has been under constant urban-development pressure. Extraction of fresh water for irrigation has allowed the salt wedge to drive further inland than previously experienced. The impacts of urbanization are not always negative, however. Infrastructures such as the Vancouver Deltaport and the British Columbia Ferry Corporation terminal have affected the region profoundly; nonetheless, the seagrass beds of southern Roberts Bank, Boundary Bay and Semiahmoo Bay have expanded in recent decades due to improved growing conditions and the introduction of dwarf eelgrass. The habitat appears resilient to many environmental changes. The eelgrass regions support a diversity of wildlife, in particular waterfowl. Pollution and contamination Many organic and inorganic contaminants are adsorbed onto mud particles that are transported in suspension and deposited within the estuary and in the Strait of Georgia; this topic is addressed by Vingarzan and Sekela, and by Bendell-Young and others. The input of contaminants at any point along the river is of concern, as they can be eventually transported and deposited in the estuarine sediments. Sources of organic contaminants include pulp-and-paper mills, municipal wastewater-treatment facilities, urban runoff, sawmills, wood-treatment facilities, agricultural runoff, and aerial deposition. Dioxins, furans, chlorophenolics, and resin acids were found in higher concentrations at sites up to 300 km downstream of pulp-and-paper mills than at unaffected reference sites. Seasonal hydrological changes clearly influenced contaminant concentrations, however. Levels of dioxins and furans were found to have decreased dramatically since the implementation of abatement measures at the mills, and none of the contaminants were found to exceed federal water-quality guidelines or provincial criteria for the protection of aquatic life. Bendell-Young and others are particularly concerned with the biogeochemistry of the intertidal mud flats of the Fraser River delta. Specific areas within the intertidal region have been subjected to point sources of pollution, such as the Iona Island sewage treatment plant, which have introduced trace metals and organic contaminants into these highly productive regions. It is imperative to obtain a good understanding of the biogeochemical processes that occur within these intertidal regions in order to appreciate the long-term effects of the introduction of these pollutants. Brand and Thompson attempt to investigate the effects of pollutants through toxicological studies of fish and invertebrates in the Fraser River estuary. They focus their investigations on several 'indicator' species in which toxicological effects can be observed and identified. Local effects of pollution appear in the invertebrate community as changes in species diversity or as shifts to more pollution-tolerant species. Several fish species, such as bottom-feeding flat fish, are exposed to a variety of sedimentbound contaminants, either by direct contact or through consumption of contaminated food organisms. Biomarkers such as detoxification enzymes, bile metabolites, and precancerous and/or cancerous lesions have been found in these fish in the estuary. As with any urban centre, significant human healthcare issues arise as a result of urbanization and of the quality of the community's health-care infrastructure. Hertzman points out that two of the more significant health hazards associated with urbanization are exposure to lead among children and threats to respiratory health from particulate air pollution. Exposure to lead has been significantly reduced since regulations were employed to eliminate the addition of lead to gasoline. Air pollution, however, continues to be a health concern. Jackson examines atmospheric impacts of urbanization in the Lower Mainland. When humans alter a natural landscape into an urbanized one, a number of atmospheric environmental impacts result. Perhaps the most potentially serious of these is air pollution. Among the 'chemical soup' that hangs over the Fraser River delta region, people are most concerned about ozone and inhalable particulates because of their effects on the ecosystem (ozone primarily) and on human health (ozone and particulates). Steps being taken by the regional government should reduce or at least stabilize air-pollution levels in the region. Climate Extreme climatic events make the low-elevation regions of the Fraser River delta susceptible to flooding, as noted by Woods in this volume. The Fraser River, with a drainage basin encompassing some 233 000 km2, is the largest river in British Columbia. Depending on ground elevation and on location along the river, flooding of the estuary and delta can be caused by winter storm surges originating from the Strait of Georgia, and/or by high spring-freshet flows on the Fraser River. As well, heavy fall and winter rainfalls, exacerbated by poor drainage and high tide levels, combine to cause high water tables and overland flows within dyked areas. Significant and damaging floods occurred in 1894, 1948, and 1969. The delta is presently surrounded by a system of dykes and pumping stations, to protect the emergent areas from river floods and storm surges with wave runup. It must be noted that many of these dykes and facilities predate building codes and were not constructed to withstand earthquake forces. Current issues relating to flood control include the maintenance of works in light of changing public priorities and of environmental conflict. Future consideration could be given to upgrading existing works to higher standards, justified by the rapidly increasing population and development levels in the affected areas. Specifically, upgrades should address the effects of sedimentation, earthquakes, relative sea-level changes, and possible changes in climatic conditions. Climate significantly affects the diversity and abundance of flora and fauna and the biomass productivity in the Fraser River delta and surrounding area. It also is a factor attracting humans to the region as a place to live. Jackson summarizes the characteristics of the local climate and the physiographic features most important in modulating the weather and climate, ranging from large-scale to small-scale effects. The ocean, mountains, valleys, and urbanization all contribute to creating unique and locally variable climate characteristics. For example, the city of Vancouver can experience temperatures 7°C higher than rural areas, due to the urban heat-island effect, and the nearby mountains can experience three times the precipitation of the adjacent lowlands. These variations, combined with spatial variations in ground materials, have a significant influence on the ecology of the region and on the potential impact of humans. The supply of fresh water is also critical to the flora and fauna of the Fraser Lowland (including humans, of course). Typically, there is a surplus of precipitation in winter (December through April), and a shortage in summer as evaporation exceeds precipitation. Paving of natural surfaces dramatically alters the hydrology of an urban area, causing increased runoff and alteration or removal of natural watercourses. In addition, farming irrigation and other anthropogenic uses of water further draw down the water table in summer, allowing salt water from the adjacent Strait of Georgia to penetrate further beneath the delta and potentially contaminate water supplies. The climate further ensures that the Fraser River delta is rich in ecological diversity, as discussed by Schaefer. The region sustains abundant marshes, old fields, bogs, and agricultural land, which are interconnected with surrounding marine ecosystems and with the urban forests of Vancouver to the north and of the Surrey uplands to the south. As a consequence, the delta is of global significance as a major stopover point for migrating birds along the Pacific Flyway and as a vital support to the salmon runs of the Fraser River. Natural ecosystems of the delta, however, have been significantly degraded and continue to be threatened by urbanization and population growth. Several major short- and long-term programs are in place to restore and manage several of the affected areas. 'What will be the effects of a changing climate on the Fraser River estuary?' is the question addressed by Taylor. Rising concentrations of greenhouse gases threaten to increase the average global temperature and total precipitation. Unchecked, the atmospheric concentration of carbon dioxide will have doubled relative to pre-industrial times within the next 50 to 80 years. This increase may cause regional climate patterns and sea level around the world to change substantially. The magnitude and timing of these regional climate changes can only be estimated, making it difficult to accurately predict how physical and biological systems will change in the Fraser River delta or anywhere else in the world. Responses could range from a substantial rise in sea level, which could threaten the dyking systems of the Fraser River delta, to increased immigration pressure on the Fraser River delta from environmental refugees fleeing climate-change-ravaged homelands outside Canada. Knowledge of the potential changes that might put pressure on the Fraser River delta will be useful in planning the development of the delta for the future. Trade and commerce Indigenous people inhabited the fertile Fraser River valley for perhaps as much as 9000 years before the arrival of European settlers. Kew provides a brief history of the first towns of the Fraser estuary, occupied by the First Nations Halkomelem society of the Coast Salish Culture. The Fraser River and adjacent Strait of Georgia served as a transportation corridor for aboriginal people, and thus the Fraser River delta was a meeting place and trade centre for many of the indigenous communities of southwestern British Columbia and of the Pacific Northwest. The indigenous people of the Fraser Lowland had a highly evolved societal structure and infrastructure that survived for thousands of years. Their societal infrastructure was analogous in many aspects - industry, trade and commerce, leadership, and housing - to that of the modern civilization at this site. The First Nations' long history of stable and bountiful use of the land can serve as an example to focus thinking about the underpinning concepts of sustainability. Kew emphasizes that in order for our modern culture and society to sustain itself, we must understand that humans are an integral component of the ecological system, much as the First Nations societies did . As the Fraser Lowland was a centre of trade and commerce for aboriginal people in centuries past, in these modern times it has become a centre for global trade and commerce. Davis and Hutton explain how the Greater Vancouver Regional District is a critical economic gateway to Pacific Rim nations. During the twentieth century, this region evolved from a centre of administrative, distributive, and commercial services for the province into a gateway for the increasingly integrated network of urban economies on the Pacific Rim. Two related phenomena have been central to this transformation: a restructuring of the metropolitan economy and a reorientation of the economy's export markets. The restructuring of the Vancouver economy has resulted primarily from a shift of the region's employment from extractive (agriculture, mining, forestry, and fishing) and manufacturing activities to service activities. This shift has resulted in the rise to dominance of producer services: those professional and technical services (e.g. engineering, telecommunications, and management consulting) that are information-intensive and require a highly skilled labour force. As producer services become increasingly valued in global markets, their exportation from the region continues to expand. The most rapidly growing markets for these exports are located on the Pacific Rim. Links with the Pacific Rim include travel and tourism, immigration, finance and investment, and a growing Asian social and cultural orientation within the metropolitan region. Management and sustainability Integration of all of the above-mentioned issues, sometimes with competing or incompatible interests, is a complex problem in management. Dorcey places this management issue in the context of FREMP, the Fraser River Estuary Management Program. This body facilitates co-ordination among the activities of more than one hundred different agencies in implementing the Estuary Management Plan established for the Fraser River estuary. The goal of the plan is to improve environmental quality in the Fraser River estuary while providing economic development opportunities and sustaining the quality of life in and around the estuary. Management of the Fraser River estuary is not simply a scientific problem; it involves the legal community as well, especially with respect to resolving issues involving competing interests. Paisley presents a paper that describes the legal framework for Fraser River estuary governance and analyzes the role of laws and of the legal system in the conservation and protection of the natural resources of the Fraser River estuary, in particular the Pacific salmon resource. He concludes that there needs to be a great deal more emphasis on compliance, enforcement, the creative utilization of scientific information in environmental decision-making, and the harnessing of market forces in order for the resources of the Fraser River estuary to be sustainable in the twenty-first century. The intent of sound management practice for the Fraser River estuary is ultimately to allow the numerous stakeholders, including the natural environment, to coexist in a sustainable way. Since the Lower Mainland of British Columbia was first settled, it has been altered by development for human purposes, largely in an unsustainable way. Mooney examines a landscape ecological model of sustainability for the Fraser River estuary, compares it with the current compartmentalization model of development, and proposes that the landscape ecological model and the concept of diversity in landscape planning and development provide a basis for achieving sustainable land use. Perhaps we should apply the lessons of the First Nations people and provide sound stewardship of the natural environment so that we may live in harmony with it and reap benefits from it for the centuries to come. In the final paper in this bulletin, Woollard and Rees attempt to come to terms with the definition of sustainability and question the role of science in addressing the complex issues surrounding threats to the environment and environmental degradation in the Fraser River estuary. They argue that the key to sustainability lies in our ability to build robust cross-linkages between science and other intellectual traditions and the humanities, to build bridges that will allow us to better understand our collective values, better apply our knowledge-gathering and -disseminating tools, better understand the ecological consequences of human action, and better assist our political and social structures in acquiring the knowledge required for taking wise action.
Information Type report
Regional Watershed Lower Fraser
Sub-watershed if known
Aquifer #
Project status complete
Contact Name Andree Blais-Stevens
Contact Email [email protected]