Showing papers by "Ontario Ministry of Transportation published in 1987"

Bedform migration and bed‐load transport in some rivers and tidal environments

Abstract: Reliable field data obtained by directly measuring bed-load transport of fine- to coarse-grained bed material are extremely scarce, mainly because of the difficulty of sampling accurately. Therefore, the verification of bed-load transport formulae is largely based on flume experiments, which refer to unrealistic shallow-water conditions. In this study, some bed-load transport formulae were tested against data from natural environments. As an alternative to ascertaining the bed-load transport rate by sampling the bed-load, the transport rate was deduced from data on bedform height and bedform celerity. For this purpose, 43 sets of data from rivers, representing a wide range of bed material, bedform dimensions and hydraulic conditions were collected as were some sets of data from tidal settings. Two formulae were used for the prediction of the bed-load transport: the formula of Van Rijn (1981) and the Kalinske (1947) formula as approximated by Elzerman & Frijlink (1951) (and, in the present study, slightly modified for application to tidal waters). Both the bed-load function of Van Rijn and the modified formula of Kalinske-Frijlink require data which are easily obtained and that can be measured accurately. At those stages of the flow when bed-load transport was high the Van Rijn function tended to overestimate that transport. For flow stages when bed-load transport was low the opposite was true. The modified Kalinske-Frijlink function gave consistently good results: 86% of the transport rates predicted using the river data were within 0·5–2·0 times the values actually measured.

Regularity and irreversibility of weekly travel behavior

Abstract: Dynamic characteristics of travel behavior are analyzed in this paper using weekly travel diaries from two waves of panel surveys conducted six months apart. An analysis of activity engagement indicates the presence of significant regularity in weekly activity participation between the two waves. The analysis also shows a general lack of association between regularity in activity participation and change in person and household attributes, suggesting the presence of behavioral inertia or response lags. It is further shown that observed trip rates do not exhibit patterns that would be observed if travel behavior had no response lag and no history dependence. The results point to the needs for models that are capable of representing these aspects of travel behavior.

Probabilistic approach to consistency in geometric design

Abstract: The practice of evaluating consistency in geometric design is addressed. The current practice is based on comparing the speed of a certain percentile value at the points of interest. The underlying reasoning is to control the amount of speed change incurred by the drivers. This paper shows that comparing the two speed distributions does not give the full picture of all the speed changes that the drivers incur. In the extreme case, it is argued that, theoretically, even when the two distributions are identical, it is still possible that each driver will experience a speed change. Hence, it is proposed to obtain and analyze the distribution of the speed differences. Using an empirical example, it is shown that the current approach is likely to underestimate the amount of the speed changes, and hence, the current approach is prone to accept inconsistent designs as consistent.

Isotopic variation in the shells of recent marine invertebrates from the Canadian pacific coast

Abstract: Shell carbonate of Balanus, Diadora, Mytilus and Calliostoma contain relatively light ° 13 C-values which suggest that deep ocean waters, enriched with 12 C of dissolved inorganic carbon (TDC), well up onto the coast of British Columbia, Canada. Another explanation for the light δ 13 C-values of the shells is extensive oxidation of organic carbon in the shallow surface waters along the coast, or kinetic fractionation related to growth rate of the organisms. Organisms that incorporate carbon and oxygen into shell carbonate in isotopic equilibrium with ambient seawater were used to calculate water temperatures. The calculated temperature of 7°C for Balanus suggests that these invertebrates preferentially precipitate calcite during the cooler months of the year, since the yearly temperature range of the water at Cape Beale is between 6.2° and 12.8°C The calculated temperature of 10°C for the limpet implies that this organism calcifies shell carbonate throughout the year. The bivalves Mytilus and Calliostoma with temperatures of 11° and 12°C, respectively, apparently form shells during the warmer summer months of the year. The barnacle Balanus and the limpet Diadora incorporate carbon and oxygen isotopes into shell carbonate in equilibrium with ambient seawater. This observation also applies to Mytilus and Calliostoma from Cape Beale, but not to their representatives from Lucy Island. Anomalous oxygen isotopic values are exhibited by the bivalve Clinocardium at both localities. Similarily, carbon values are anomalous for the carbonate of worm tubes ( Eudistylia ). These deviations of the isotopic compositions from expected values are probably related to changes in the nutrient level and/or water temperature.

Comparative environmental impacts of different modes

Abstract: While modern railway systems in general are considered to have comparatively low environmental impacts, high speed rail systems require special attention to ecological appraisal. Two case studies are presented - the new rail lines of the West German Federal Railways, and the European high speed rail project Paris-Brussels-Cologne/Amsterdam — which show that environmental compatibility can be costly and time-consuming. However, it would seem that the environment would not be a main issue for the proposed Amsterdam-Groningen-Hamburg connection if it primarily used existing rail lines.

Operational air surveillance and experiences in the netherlands

Abstract: Surveillance of suspected oil pollution incidents in the Dutch sector of the North Sea by aircraft has proven useful in reducing the amount of oil discharged and apprehension of violaters. An operational approach based on experience has been developed, using both visual and remote sensing observations. A number of practical suggestions have been put forward for use in establishing whether or not a violation has occurred.

The market study review process

Abstract: When market studies dealing with proposed shopping centre space additions are submitted for review and approval to municipalities most are not sufficiently scrutinized. This is because academic and professional training in such matters is lacking. The intent of this paper is to present, step by step, evaluative criteria for a systematic review of such studies.