Flood risk mapping in southwestern Nova Scotia: Perceptions and concerns

Flood risk mapping allows for informed decision making regarding personal and community planning. Resistance to flood risk mapping can be driven by potential decline of property values. This paper explores resistance to flood risk mapping through the lens of climax thinking. Climax thinking is a novel theory guiding explorations of resistance to proposed land use changes. The aim of this study was to understand flood experiences, the presence of resistance to flood risk mapping, and whether climax thinking could help explain this resistance. To address this, surveys were administered to residents in the Nova Scotian towns of Liverpool and Bridgewater. We found that one third of respondents have experienced flooding, yet the majority have not seen a flood risk map, nor were they concerned about the potential impacts of flooding. Only one sixth of respondents exhibited resistance to flood risk mapping because of potential loss to property value. Dimensions of climax thinking were predictive of this resistance, specifically ignorance of an individual's own ability to adapt and inability to recognize the impact of their adaptation decisions on others, which together quadrupled the predictive power of the ordinal regression model. These insights can be applied to support the acceptance of flood risk mapping.     

Buffon's Needle and the Probability of Intercepting Short-Distance Trips by Multiple Screen-Line Surveys

For transport planning purposes, information on origin-destination movements may be obtained by stopping traffic at the roadside and interviewing drivers. The roadside interview stations are usually located so that they lie on one of a number of lines (called screen lines) that cross from one side of the survey area to another. In this way, all movements with the origin on one side of a screen line and the destination on the other are intercepted. For regional surveys, a grid of screen-lines may be used. The movements intercepted are not, however, representative of all those in the region. That is because shorter-distance movements are underrepresented; the coarser the grid, the worse the effect. The extent of this underrepresentation is estimated in this paper by calculating the probability of intercepting a trip of given direct length, under the assumption that the screen lines constitute a uniform rectangular grid, and that trips of a given length are distributed over the region at random. The result is an extension to the Buffon needle problem. Ways in which such a result, obtained for an idealized situation, may be extended to apply to more realistic situations, are discussed: in particular it is shown how the trip-length frequency distribution of all trips may be estimated from that of intercepted trips, using a simple formula that is applicable to a much more general pattern of screen lines.