Greater Vancouver Regional District Research Articles

Examining the relationship between urban density and sense of community in the Greater Vancouver Regional District

This study investigated whether highly dense urban environments have a negative influence on residents' sense of community. It used an online survey to measure respondents' sense of community and compared it to the density of the areas in which they live. Findings of this study suggest that urban density has a negative but weak relationship with sense of community among survey respondents. They also suggest that providing some types of public space may encourage higher levels of sense of community among residents in high-density areas.

Examining the Relationship between Urban Density and Sense of Community in the Greater Vancouver Regional District

Examining the Relationship between Urban Density and Sense of Community in the Greater Vancouver Regional District

Enhancing the Evaluation and Interpretability of Data-Driven Air Quality Models

Resolving spatial variability in ambient air pollutant and quantifying contributing factors are critical to human exposure assessment and effective pollution control. Data-driven techniques have been employed in air quality modeling due to their capability to capture the complex relationships in data as well as for the benefit of fast and easy implementation. In this study, we addressed two issues on model evaluation and interpretability by applying two common data-driven approaches, linear regression (LR) and random forest (RF) with potentially predictive land-use predictor variables to predict spatial variations of air pollution in an urban setting. The data came from the measurement of ambient nitrogen dioxide (NO2) concentrations in the Greater Vancouver Regional District in Canada. First, we showed that the model performance was sensitive to the division of training and test sets. Applying a limited number of hold-out validations or cross-validations and reporting the mean model metrics cannot capture the variability and fairly evaluate the model performance. We proposed repeated cross-validations (RCVs) as a reliable evaluation method that accounts for both mean and variance. Second, there is not a consistent approach to measure the importance of predictor variables and quantify their contributions among different types of data-driven models. Traditional approaches only reflect the relative importance among predictor variables in terms of predictive power without a quantification of contribution to the model output. We proposed to apply SHapley Additive exPlanations (SHAP), a Shapley-value-based explanation method based on the coalitional game theory, as a unifying framework to interpret and compare different types of data-driven methods. We showed that SHAP is capable of 1) calculating predictor variable’s contribution to each data point; 2) ranking the importance of predictor variables in terms of their contributions to the model output. The results indicated that different models may favor different predictor variables and result in different interpretability.

High spatial resolution landscape indicators show promise in explaining water quality in urban streams

Urban streams are subject to a myriad of complex stressors associated with impervious surfaces, which impact delivery of pollutants. Landscape indicators (e.g. the amount and arrangement of land cover) are widely used to help monitor water quality, yet their application in highly urbanized settings remains poorly understood. Here, we explored the utility of landscape indicators for explaining water chemistry and bacterial concentrations in streams throughout the Greater Vancouver Regional District, British Columbia, Canada. First, we compared high and moderate spatial resolution imagery to evaluate their relative efficacy in characterizing impervious surfaces. Second, we linked a suite of landscape indicators to major chemical properties and pollutants (e.g. dissolved oxygen, nitrate, turbidity, fecal coliform, E. Coli.) using a series of comparative statistical models. Land cover at 30-m resolution often over-estimated the proportional area of impervious surface by 0.10–0.30, sometimes doubling the amount detected using finer resolution imagery. Finer 5- and 2-m resolution imagery demonstrated little difference in estimating impervious cover. Therefore, 5-m resolution imagery was adopted for spatial analysis in the study region. Watershed-level landscape indicators explained nearly 50% of the variability in wet season concentrations of dissolved oxygen and fecal coliform. When considering the spatial configuration of impervious areas, edge density within the riparian zone explained more than 30% of the variability in fecal coliform and E. Coli. Our approach is potentially transferable to many cities worldwide facing similar challenges in monitoring urban streams.

A nonstationary peaks-over-threshold approach for modelling daily precipitation with covariate-dependent thresholds

The estimation of extreme precipitation events is a topic of growing interest and concern, particularly in highly urbanized areas. The Fifth Assessment Report by the Intergovernmental Panel on Climate Change (IPCC) reported that land-surface air temperatures have increased and that more extreme precipitation events are expected in a warmer climate. Hydrometeorological data often display nonstationary characteristics in a changing climate, prompting numerous studies worldwide. This research proposes a peaks-over-threshold (POT) approach using both stationary and covariate-dependent nonstationary thresholds (bivariate and multivariate models). The generalized Pareto (GP) distribution is fit to threshold exceedance data, which accounts for potential nonstationarity in the variability of the extreme events. The analysis herein focuses on coastal British Columbia (BC), which includes the Greater Vancouver Regional District (Metro Vancouver), due to the potential impacts of climate change in the region. Results from quantile estimates and an uncertainty analysis indicate that in the winter and summer months, there is stronger evidence of stationarity in 50-year quantiles. A trend analysis is also performed on the magnitude and frequency of POT events for winter and summer for two time periods (1976–2014 and 1986–2014). Results of this analysis indicate that globally significant trends are found in the threshold exceedance and frequency of peak events data.

Bus networks as graphs: new connectivity indicators with operational characteristics

A transit network, visualized as a graph, can be evaluated using indicators such as connectivity, coverage, directness, and complexity, among others, based on the relationships between network elements. This study focuses on the analysis of interconnected and operationally complicated bus networks, a shortcoming of existing approaches tailored to simpler, metro networks. A new procedure is proposed for drawing bus networks as graphs, by disaggregating them into sub-networks at the traffic analysis zone level. As well, improved network connectivity indicators are proposed which incorporate the influence of bus operational characteristics. The effect of bus route transfers is analyzed by introducing intermediate walking transfer edges. The contribution of this research will provide transit agencies with quantitative measures to analyze the network characteristics and the related operational attributes at a zonal sub-network level across the agency’s coverage area. The proposed methodology was demonstrated by applying it to the Greater Vancouver Regional District public transportation system.

Uncovering the Spatial Patterning of Crimes

Objectives: The main objective of this study was to see if the characteristics of offenders’ crimes exhibit spatial patterning in crime neutral areas by examining the relationship between simulated travel routes of offenders along the physical road network and the actual locations of their crimes in the same geographic space. Method: This study introduced a Criminal Movement model (CriMM) that simulates travel patterns of known offenders. Using offenders’ home locations, locations of major attractors (e.g., shopping centers), and variations of Dijkstra’s shortest path algorithm we modeled the routes that offenders are likely to take when traveling from their home to an attractor. We then compare the locations of offenders’ crimes to these paths and analyze their proximity characteristics. This process was carried out using data on 7,807 property offenders from five municipalities in the Greater Vancouver Regional District (GVRD) in British Columbia, Canada. Results: The results show that a great proportion of crimes tend to be located geographically proximal to the simulated travel paths with a distance decay pattern characterizing the distribution of distance measures. Conclusion: These results lend support to Crime Pattern Theory and the idea that there is an underlying pattern to crimes in crime neutral areas.

Effect of recycling activities on the heating value of solid waste: case study of the Greater Vancouver Regional District (Metro Vancouver)

Two main goals of the integrated solid waste management system (ISWMS) of Metro Vancouver (MV) include further recycling of waste and energy recovery via incineration of waste. These two very common goals, however, are not always compatible enough to fit in an ISWMS depending on waste characteristics and details of recycling programs. This study showed that recent recycling activities in MV have negatively affected the net heating value (NHV) of municipal solid waste (MSW) in this regional district. Results show that meeting MV's goal for additional recycling of MSW by 2015 will further reduce the NHV of waste, if additional recycling activities are solely focused on more extensive recycling of packaging materials (e.g. paper and plastic). It is concluded that 50% additional recycling of paper and plastic in MV will increase the overall recycling rate to 70% (as targeted by the MV for 2015) and result in more than 8% reduction in NHV of MSW. This reduction translates to up to 2.3 million Canadian dollar (CAD$) less revenue at a potential waste-to-energy (WTE) plant with 500 000 tonnes year(-1) capacity. Properly designed recycling programmes, however, can make this functional element of ISWMS compatible with green goals of energy recovery from waste. Herein an explanation of how communities can increase their recycling activities without affecting the feasibility of potential WTE projects is presented.

Phytochemical Diversity of Cranberry (Vaccinium macrocarpon Aiton) Cultivars by Anthocyanin Determination and Metabolomic Profiling with Chemometric Analysis

Originally native to the eastern United States, American cranberry ( Vaccinium macrocarpon Aiton, family Ericaceae) cultivation of native and hybrid varieties has spread across North America. Herein is reported the phytochemical diversity of five cranberry cultivars (Stevens, Ben Lear, Bergman, Pilgrim, and GH1) collected in the Greater Vancouver Regional District, by anthocyanin content and UPLC-TOF-MS metabolomic profiling. The anthocyanin content for biological replicates (n = 5) was determined as 7.98 ± 5.83, Ben Lear; 7.02 ± 1.75, Bergman; 6.05 ± 2.51, GH1; 3.28 ± 1.88, Pilgrim; and 2.81 ± 0.81, Stevens. Using subtractive metabonomic algorithms 6481 compounds were found conserved across all varietals, with 136 (Ben Lear), 84 (Bergman), 91 (GH1), 128 (Pilgrim), and 165 (Stevens) unique compounds observed. Principal component analysis (PCA) did not differentiate varieties, whereas partial least-squares discriminate analysis (PLS-DA) exhibited clustering patterns. Univariate statistical approaches were applied to the data set, establishing significance of values and assessing quality of the models. Metabolomic profiling with chemometric analysis proved to be useful for characterizing metabonomic changes across cranberry varieties.

Thinking Metropolis: From the ‘Livable Region’ to the ‘Sustainable Metropolis’ in Vancouver

At the metropolitan scale, the Greater Vancouver Regional District has earned acclaim for its commitments to preserving green spaces, its attention to metropolitan labour markets and employment, investments in rapid transit and the introduction of ‘compact’ and ‘complete’ communities. Recently, the regional governance authority was rebranded to ‘Metro Vancouver’, connoting a more integrative policy framework, as well as a cosmopolitan/transnational imagery; and entailing the insertion of sustainable development into planning discourses. This essay offers a critical perspective on Vancouver's planning record, and a commentary on prospects for advancing the ‘metropolitan consciousness’ required to address the developmental exigencies of the twenty-first-century city-region.

Metropolitan cooperation, theory and practice: Looking at Vancouver, BC, Canada

In North America, why and how municipalities in large metropolitan areas cooperate is a pressing question. Both in Canada and the United States, the literature has been greatly influenced by the public choice views that rational actors have very limited rational or economic incentives to cooperate unless the state steps in to rule cooperation. But beyond the ideological debate, these views are about issues of regional cooperation public choice (polycentrism); (3) metropolitan governance (new regionalism); and (4) rescaling and re-territorialization, which are tightly linked to value systems where: a) metropolitan government centers on monocentric efficiency; b) public choice on polycentric efficiency; c) metropolitan governance on equity and competitiveness; and d) rescaling and re-territorialization centers on global competitiveness. These discussions set the stage for this paper's main argument: in North America, the Greater Vancouver Regional District is an exemplary commitment to metropolitan cooperation.Spanish En Norteamérica esta emergiendo una pregunta urgente: ¿por qué y cómo cooperan los municipios de las grandes áreas metropolitanas? En Canadá y Estados Unidos, la literatura ha sido fuertemente influenciada por la teoría del public choice, según la cuál los actores racionales tienen muy escasos incentivos racionales o económicos para cooperar, a menos que el estado intervenga y ordene la cooperación. Obviamente, más allá del debate ideológico, estas visiones abordan asuntos de cooperación regional desde varias perspectivas normativas: (1) el gobierno metropolitano (antiguo regionalismo); (2) public choice (policentrismo); (3) gobierno metropolitano (nuevo regionalismo); y (4) reorganización escalar y re-territorialización, transformaciones que se conectan estrechamente al sistema de valores donde: a) el gobierno metropolitano se centra en la eficiencia monocéntrica, b) la public choice sobre la eficiencia policéntrica, c) la gobernanza metropolitana en la equidad y la competitividad, y d) la reorganizacion escalar y reterritorialización se enfoca sobre competitividad global. Estas discusiones preparan el escenario para el principal argumento de este artículo: en Norteamérica, el Gran Distrito Regional de Vancouver es probablemente un compromiso ejemplar de cooperación metropolitana.French En Amérique du Nord une question pressante se pose, à savoir pourquoi et comment les municipalités des grandes métropoles coopèrent. Tant au Canada qu'aux États-Unis la li érature a été fortement influencée par la théorie du choix public, selon laquelle les acteurs rationnels ne trouvent que très peu d'incitations rationnelles ou économiques qui les incitent à coopérer, à moins que l'État n'intervienne pour ordonner la coopération. Il est toutefois évident que, derrière le débat idéologique, ces débats abordent les questions de coopération régionale à partir de différentes perspectives normatives, (1) le gouvernement métropolitain (ancien régionalisme), (2) le choix public (polycentrisme), (3) la gouvernance métropolitaine (nouveau régionalisme), et (4) la réorganisation scalaire et la reterritorialisation, des transformations qu'elles relient étroitement à des systèmes de valeurs, où : a) le gouvernement métropolitain se centre sur l'efficacité monocentriste, b) le choix public sur l'efficacité polycentriste, c) la gouvernance métropolitaine sur l'équité et la compétitivité, et d) la réorganisation scalaire et la reterritorialisation se focalisent sur la compétitivité globale. Ces discussions forment la toile de fond du principal sujet de cet article : en Amérique du Nord, le Greater Vancouver Regional District constitue probablement un compromis exemplaire en matière de coopération métropolitaine.

A New Record Size for the Northern Desert Nightsnake (Hypsiglena chlorophaea deserticola)

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Transferability of Community-Based Collision Prediction Models for Use in Road Safety Planning Applications

Collision prediction models (CPMs) are statistically developed mathematical models that relate the occurrence of traffic collisions to various traits or explanatory variables of locations and zones. This paper describes the use of several recently developed community-based, macro-level CPMs and model-use guidelines in a CPM transferability case study for spatial and temporal transferability. The objective was to test the model-use guidelines in an application that involved transferring CPMs developed using 1996 data for the Greater Vancouver Regional District (GVRD) for use in the Central Okanagan Regional District (CORD) using 2003 data. The GVRD and CORD are regions located 400 km apart in the Province of British Columbia, Canada. The case study was carried out in two parts. First, CPMs were developed using 2003 data for the City of Kelowna following recommended community-based, macrolevel collision prediction model development guidelines. Second, existing CPMs were transferred from the GVRD to the CORD, using the recommended transferability guidelines. An analysis of the results revealed that macrolevel CPM transferability was possible and no more complicated than microlevel CPM transferability. To facilitate the development of reliable community-based macrolevel collision prediction models, it is recommended that CPMs be transferred rather than developed whenever and wherever communities lack sufficient data of adequate quality.

Strategy for use of alternative waste sort sizes for characterizing solid waste composition

Although there is widespread interest in identifying opportunities to improve solid waste management, current methodologies for quantifying the number of waste sorts needed for categories with only small percentages of the waste stream which require a large number of waste sorts. In response, for those categories (e.g. batteries, gypsum, PVC, plastic film) with small percentages in the waste stream, an alternative methodology has been developed. By employing a large quantity of solid waste for sorting (e.g. 408 kg), the standard deviation of percent weight (of a category) is shown to be reduced by approximately 45%. This reduction in standard deviation translates to a reduction of about 65% in the number of samples required to characterize the waste. The proposed methodology is demonstrated using data taken from solid waste sorting of Greater Vancouver Regional District.

Modeling urban growth using a variable grid cellular automaton

Constrained cellular automata (CA) are frequently used for modeling land use change and urban growth. In these models land use dynamics are generated by a set of cell state transition rules that incorporate a neighborhood effect. Generally, neighborhoods are relatively small and therefore only a limited amount of spatial information is included. In this study a variable grid CA is implemented to allow incorporation of more spatial information in a computationally efficient way. This approach aggregates land uses at greater distances, in accordance with a hierarchical concept of space. More remote areas are aggregated into consecutively larger areas. Therefore the variable grid CA is capable of simulating regional as well as local dynamics at the same time. The variable grid CA is used here to model urban growth in the Greater Vancouver Regional District (GVRD) between 1996 and 2001. Calibration results are tested for goodness of fit at the cellular level by means of the kappa statistic and for land use patterns by means of cluster size analysis and radial analysis. Kappa results show that the model performs considerably better than a neutral allocation model. Cluster and radial analysis indicate that the model is capable of producing realistic urban growth patterns.

A field-based procedure for determining number of waste sorts for solid waste characterization

Current methodologies for estimating the number of waste sorts require prior information on statistics (mean and standard deviation) for specific waste categories. The methods often require an iterative procedure or computer software to estimate the number of sorts required and the required statistics may change both spatially and temporally. To overcome the need for prior statistical information and avoid the need for iterative effort, a real-time methodology is developed to determine the required number of waste sorts for a waste category while sampling in the field for solid waste characterization. The information on required numbers of waste sorts is field-based and evolves during the sampling by utilizing real-time data to characterize the means and standard deviations. The proposed approach does not require prior information. The application of proposed methodology is demonstrated using the data from the Greater Vancouver Regional District (GVRD) for the primary categories of paper, glass, and secondary category glass-beverage.

Minimizing effects of scale distortion for spatially grouped census data using rough sets

Census data has been widely used for community evaluation based on demographic and socioeconomic variables. However, the analysis is typically associated with specific areal units and the results often change when the size of the census configuration changes leading to scale distortions. Various approaches such as optimal zoning systems and multivariate statistical analysis have been developed to address the scale problem. But limitations in these approaches have led to the use of non-statistical methods to tackle the scale problem. This study combines a non-statistical method with descriptive statistical measures to develop a rough sets approach to constructing a census-based deprivation index (DI) and to determine its relationship to a recent immigrant population using the 2001 Canadian census. Application of the approach in the Greater Vancouver Regional District shows that rough sets can stabilize relationships for spatially grouped census data by minimizing scale distortions. Scale sensitivity measures are also estimated to translate DI relationships across three census configurations. The rough sets approach is suitable for areal data analysis because it is resistant to nonlinearity, outliers, and assumes no prior relationship between variables.

Enhancing a GIS Cellular Automata Model of Land Use Change: Bayesian Networks, Influence Diagrams and Causality

AbstractCellular Automata (CA) models at present do not adequately take into account the relationship and interactions between variables. However, land use change is influenced by multiple variables and their relationships. The objective of this study is to develop a novel CA model within a geographic information system (GIS) that consists of Bayesian Network (BN) and Influence Diagram (ID) sub‐models. Further, the proposed model is intended to simplify the definition of parameter values, transition rules and model structure. Multiple GIS layers provide inputs and the CA defines the transition rules by running the two sub‐models. In the BN sub‐model, land use drivers are encoded with conditional probabilities extracted from historical data to represent inter‐dependencies between the drivers. Using the ID sub‐model, the decision of changing from one land use state to another is made based on utility theory. The model was applied to simulate future land use changes in the Greater Vancouver Regional District (GVRD), Canada from 2001 to 2031. The results indicate that the model is able to detect spatio‐temporal drivers and generate various scenarios of land use change making it a useful tool for exploring complex planning scenarios.

Nutritional implications of biosolids and paper mulch applications in high density apple orchards

A field experiment was designed to assess the effects on tree nutrition of surface application of municipal biosolids and shredded paper mulch, which have previously been reported to improve the performance of high-density apples despite wide differences in nutrient content. The experiment involved four treatments which included two levels (with or without) of two organic amendments, shredded paper mulch and Greater Vancouver Regional District (GVRD) municipal biosolids. Treatments were established over a 2 m wide strip centred on the tree row in a high-density (3700 trees ha-1) Golden Delicious (Malus × domestica Borkh.) orchard in the year of planting (1997) and maintained until 2004. GVRD-biosolids was applied at 40 t ha-1 (DW) in 1997 and 20.3 t ha-1 (DW) in 2001 potentially supplying larger amounts of all plant nutrients (N, P, K, Mg, Zn, Cu and Mn) except Ca than the paper mulch. All trees received standard commercial treatments of drip fertigation of 30 g N tree-1 yr-1 and 20 g P tree-1 in the establishment year. Leaf N concentration was unaffected by biosolids application and decreased, but not to inadequate concentrations, in 3 of 6 yr for trees grown in the high C:N ratio shredded paper mulch. This response indicates the effectiveness of drip fertigated N. Leaf K declined to inadequate concentrations by the end of the experiment, regardless of treatment, but trees in the paper mulch treatment were able to sustain higher leaf K, were more vigourous, had higher yield the first three fruiting seasons and cumulatively after 8 yr despite the low N and K content of the paper. Improved K uptake was attributed to better distribution of soil moisture beneath the mulch but for long-term sustainable production, K fertigation would have been desirable. Biosolids application often raised leaf Zn, Cu and Mn concentration but increases were modest, with concentrations of Zn insufficient to change standard commercial recommendations for annual dormant Zn applications. Key words: Leaf N, K, Zn, Cu and Mn, nutrient additions, organic amendments, vigour, yield

The Clear-water Paradox of Aquatic Ecosystem Restoration

Anders is a fi sheries scientist and an associate consultant with Cramer Fish Sciences and serves as affi liate faculty in the University of Idaho’s Department of Fish and Wildlife Resources in Moscow, Idaho. He can be reached at anders@fi shsciences.net. Ashley is a limnologist and environmental engineer with the Greater Vancouver Regional District and an adjunct professor in the Civil Engineering Department at the University of British Columbia, Vancouver.