Effects of different normalization, aggregation, and classification methods on the construction of flood vulnerability indexes

Index-based approaches are widely employed for measuring flood vulnerability. Nevertheless, the uncertainties in the index construction are rarely considered. Here, we conducted a sensitivity analysis of a flood vulnerability index in the Maquiné Basin, Southern Brazil, considering distinct normalization, aggregation, classification methods, and their effects on the model outputs. The robustness of the results was investigated by considering Spearman’s correlations, the shift in the vulnerability rank, and spatial analysis of different normalization techniques (min-max, z-scores, distance to target, and raking) and aggregation methods (linear and geometric). The final outputs were classified into vulnerability classes using natural breaks, equal interval, quantiles, and standard deviation methods. The performance of each classification method was evaluated by spatial analysis and the Akaike’s information criterion (AIC). The results presented low sensitivity regarding the normalization step. Conversely, the geometric aggregation method produced substantial differences on the spatial vulnerability and tended to underestimate the vulnerability where indicators with low values compensated for high values. Additionally, the classification of the vulnerability into different classes led to overly sensitive outputs. Thus, given the AIC performance, the natural breaks method was most suitable. The obtained results can support decision-makers in reducing uncertainty and increasing the quality of flood vulnerability assessments

Evaluating GIS based water budget components applicability and availability for the Lagan River catchment

Using open-access data sets on water and soil from Swedish authorities and compiling them in a QGIS-programme made it possible to present and visualise the water budget of the Lagan River Catchment. Based on the estimations of the water volume in groundwater reservoirs and lakes the total maximum available volume in the Lagan River Catchment area was determined to be 9.36 km3. Of this 75.9% (7.10 km3) is found within groundwater reservoirs and 24.1% (2.26 km3) is present in lakes. This study indicates that GIS-based parameters are useful for specifying what a water budget in a catchment area looks like.The use of GIS-based parameters also allows for the development of interactive maps which can be used to visualize different conditions in the catchment area. In addition, many people who work with water management have a good habit of using GIS tools. Utilizing open data sources means that the number of additional measurements can be kept low. Furthermore, the use of open sources contributes to increased transparency in the development proces

Evaluating summarised radionuclide concentration ratio datasets for wildlife

Concentration ratios (CRwo-media) are used in most radioecological models to predict whole-body radionuclide activity concentrations in wildlife from those in environmental media. This simplistic approach amalgamates the various factors influencing transfer within a single generic value and, as a result, comparisons of model predictions with site-specific measurements can vary by orders of magnitude. To improve model predictions, the development of 'condition-specific' CRwo-media values has been proposed (e.g. for a specific habitat). However, the underlying datasets for most CRwo-media value databases, such as the wildlife transfer database (WTD) developed within the IAEA EMRAS II programme, include summarised data. This presents challenges for the calculation and subsequent statistical evaluation of condition-specific CRwo-media values. A further complication is the common use of arithmetic summary statistics to summarise data in source references, even though CRwo-media values generally tend towards a lognormal distribution and should, therefore, be summarised using geometric statistics. In this paper, we propose a statistically-defensible and robust method for reconstructing underlying datasets to calculate condition-specific CRwo-media values from summarised data and deriving geometric summary statistics. This method is applied to terrestrial datasets from the WTD. Statistically significant differences in sub-category CRwo-media values (e.g. mammals categorised by feeding strategy) were identified, which may justify the use of these CRwomedia values for specific assessment contexts. However, biases and limitations within the underlying datasets of the WTD explain some of these differences. Given the uncertainty in the summarised CRwo-media values, we suggest that the CRwo-media approach to estimating transfer is used with caution above screening-level assessments

Uncertainty analysis in a GIS-based multi-criteria analysis tool for river catchment management

The importance of uncertainty analysis has been increasingly recognised, due to the influence of uncertainties in data, models and expert judgements. However, the successful integration of uncertainty analysis into multi-criteria analysis (MCA) has rarely been achieved. This paper analyses uncertainty sources in MCA. General methods of uncertainty analysis in MCA are reviewed, including probabilistic methods, indicator-based methods and fuzzy logic. Building on this review, an uncertainty analysis module developed for use within a GIS-based MCA tool for catchment management is presented. In this module, the influence of uncertainties on decision-making can be visually explored using an indicator-based method. The indicator-based method provides a pragmatic approach to communicating areas of uncertainty to decision-makers without assuming any prior knowledge of uncertainty analysis techniques. This enables uncertainty analysis to be more effectively operationalised within the decision-making process. An application example in the Tamar catchment, southwest UK, is used to illustrate the capability of the uncertainty analysis module when applied in a decision-making context

Using spatial multi-criteria analysis as an appraisal tool for bus rapid transit trunk and feeder routes: a case study in the City of Tshwane, South Africa

Private car use around the world has grown increasingly over the last decades. One effect of this is traffic congestion, which results in various detrimental environmental, economic and social impacts. Public transport has been identified as an effective solution to congestion. In South Africa, investment into public transport has led to the implementation of full and partial Bus Rapid Transit (BRT) systems. The policy and implementation measures of these BRT systems have been modelled, to varying degrees, according to Colombia’s TransMilenio BRT. However, BRT systems in South Africa have not been as successful as TransMilenio. Failures of South African BRTs can be traced back to many reasons, one of which is an inadequate conduction of an ex ante appraisal. This dissertation intended to close a literature gap on the use of ex ante appraisal in South African transport projects. At the time of composing this thesis (February 2017), South Africa did not have a standard appraisal tool for the selection of appropriate transport projects and road-based public transport routes. This resulted in systems that were not designed in context and, hence, underperformed for the context in which they were implemented. The contextually insensitive design of BRTs and the effects thereof constituted the conceptual departure point for this research. Accordingly, this dissertation aimed to explore Spatial MultiCriteria Analysis (SMCA) as a viable appraisal tool for BRT routes. The City of Tshwane formed the study area of the investigation. SMCA is a decision-support tool that combines multi-criteria analysis (MCA) and geographic information systems for evaluating decision problems whose criteria and alternatives have spatially explicit dimensions. This method was chosen over traditional appraisal tools such as MCA and cost-benefit analysis as it is more suited to routing problems. Suitable evaluation criteria were identified from five themes that were chosen from international and local trends: equity, transport efficiency and economic, social and environmental impact. Ultimately, composite suitability maps were generated according to the aforementioned themes, and optimal trunk and feeder routes were extracted by means of a vector-based network analysis. Four trunk and four feeder routes were quantitatively and qualitatively analysed. The quantitative analysis of the route involved determining the average impedance, route length and travel time of a route. The qualitative analysis involved determining if the optimal routes had changed to current or planned city routes. On average, trunk routes obtained a higher average impedance than feeder routes. All optimal routes differed to some degree from planned city routes. Following the determination of optimal routes, an uncertainty analysis showed that trunk routes were more sensitive than feeder routes. The sensitivity analysis also showed that the transport efficiency theme criteria were the most sensitive criteria, causing the highest mean average impedance change of all criteria. Transport efficiency criteria are thus the most important criteria in finding optimal routes. The method of research adopted in this study can be reproduced in any contemporary South African city with plans for BRT. Furthermore, the method of research can be improved upon by investigating standard evaluation criteria to be included in an SMCA routing problem to ensure a uniform appraisal standard

Using spatial multi-criteria analysis as an appraisal tool for bus rapid transit trunk and feeder routes: a case study in the City of Tshwane, South Africa

Private car use around the world has grown increasingly over the last decades. One effect of this is traffic congestion, which results in various detrimental environmental, economic and social impacts. Public transport has been identified as an effective solution to congestion. In South Africa, investment into public transport has led to the implementation of full and partial Bus Rapid Transit (BRT) systems. The policy and implementation measures of these BRT systems have been modelled, to varying degrees, according to Colombia’s TransMilenio BRT. However, BRT systems in South Africa have not been as successful as TransMilenio. Failures of South African BRTs can be traced back to many reasons, one of which is an inadequate conduction of an ex ante appraisal. This dissertation intended to close a literature gap on the use of ex ante appraisal in South African transport projects. At the time of composing this thesis (February 2017), South Africa did not have a standard appraisal tool for the selection of appropriate transport projects and road-based public transport routes. This resulted in systems that were not designed in context and, hence, underperformed for the context in which they were implemented. The contextually insensitive design of BRTs and the effects thereof constituted the conceptual departure point for this research. Accordingly, this dissertation aimed to explore Spatial MultiCriteria Analysis (SMCA) as a viable appraisal tool for BRT routes. The City of Tshwane formed the study area of the investigation. SMCA is a decision-support tool that combines multi-criteria analysis (MCA) and geographic information systems for evaluating decision problems whose criteria and alternatives have spatially explicit dimensions. This method was chosen over traditional appraisal tools such as MCA and cost-benefit analysis as it is more suited to routing problems. Suitable evaluation criteria were identified from five themes that were chosen from international and local trends: equity, transport efficiency and economic, social and environmental impact. Ultimately, composite suitability maps were generated according to the aforementioned themes, and optimal trunk and feeder routes were extracted by means of a vector-based network analysis. Four trunk and four feeder routes were quantitatively and qualitatively analysed. The quantitative analysis of the route involved determining the average impedance, route length and travel time of a route. The qualitative analysis involved determining if the optimal routes had changed to current or planned city routes. On average, trunk routes obtained a higher average impedance than feeder routes. All optimal routes differed to some degree from planned city routes. Following the determination of optimal routes, an uncertainty analysis showed that trunk routes were more sensitive than feeder routes. The sensitivity analysis also showed that the transport efficiency theme criteria were the most sensitive criteria, causing the highest mean average impedance change of all criteria. Transport efficiency criteria are thus the most important criteria in finding optimal routes. The method of research adopted in this study can be reproduced in any contemporary South African city with plans for BRT. Furthermore, the method of research can be improved upon by investigating standard evaluation criteria to be included in an SMCA routing problem to ensure a uniform appraisal standard

Generating a New Evaluating System for Regional Scale Redevelopment Effectiveness of Brownfields in Waterloo Region Using a Multi-Criteria Analysis Mechanism

Brownfield redevelopment has been a popular topic as part of the contemporary planning literature. Encouraging brownfields’ redevelopment and improving the redevelopment effectiveness and efficiency have been two of the top concerns for planners. Redevelopments with various purposes can benefit the region in different ways. It is not necessary that redeveloping into the most common purpose would make the greatest contribution to the region. A region-wide redevelopment projects’ effectiveness evaluation will help planners have a better understanding of the region’s current situation in terms of brownfield redevelopment. This research aims to integrate a multi-criteria analysis method with brownfield redevelopment effectiveness evaluation, with the intention of suggesting improvements to brownfield redevelopment resource allocation and enlightening regional land use efficiency. During the first phase of this study, a database was generated for previously redeveloped brownfields within Waterloo Region to fill in the informational gap of region-wide redevelopment projects. During the second phase, criteria were selected that can represent redevelopments’ influences, and a multi-criteria analysis technique was used to generate a region-wide effectiveness evaluation model. The redevelopment projects in Waterloo Region have been assessed by this evaluation model. This study not only creates an information database for redeveloped brownfields in Waterloo Region, but also provides an effectiveness ranking for previous redevelopment projects and identifies the best and worst performing projects. Based on the effectiveness evaluation, the region’s performance in terms of brownfield redevelopment can also be analyzed. Waterloo Region has planning tools and policies available to provide legal and technical advice for potential developers of brownfield sites. At the same time, different levels of financial supports, such as grants and tax incentive programs, are also available in Waterloo Region. However, a lack of monitoring and evaluation of programs after redevelopments is Waterloo Region’s shortcoming. In terms of brownfield redevelopment, efficiently allocating supportive resources would be the key for the region’s next step. The region-wide brownfield repurposing activities’ effectiveness evaluation could be a start that draws attention to development of efficient brownfield redevelopment resources allocation tools in the future