Development of Trigger Levels to Assess Catchment Disturbance on Stream Suspended Sediment Loads in the Magela Creek Catchment,Northern Territory,Australia

Trigger levels for fine suspended sediment (FSS) load in streams are required to identify rainfall-runoff events that have significantly elevated FSS loads, compared with expected background loads, as a result of catchment disturbance. Stream FSS load data collected in the mine-impacted Magela Creek catchment in the wet-dry tropics were used to derive water quality management trigger levels for two approaches – a Before-After-Control-Impact Paired difference design (BACIP) and a regression relationship between observed FSS load and corresponding event discharge characteristics. The results indicate that both the BACIP and regression relationship approaches behave similarly, with similar FSS load events elevated above trigger levels. Notwithstanding this, it is recommended that in order to reliably assess the location and magnitude of a catchment disturbance on FSS load, a combination of BACIP and regression relationship approaches must be adopted. In this study, an event with a FSS load above trigger levels associated with both BACIP and the regression relationship fitted for the downstream site is considered to be significantly elevated as a result of a disturbance within the mine-impacted region. While this technique cannot conclusively determine whether the cause of the disturbance is mine-related or natural (such as fire or bank erosion), it is an efficient statistical method of identifying events that warrant further investigation and management action, if required.     

INDUSTRIAL RESTRUCTURING IN A PERIOD OF CRISIS: AN ANALYSIS OF THE CANADIAN AUTOMOBILE INDUSTRY, 1973–83.*

The recent crisis in the North American economy is rooted in the disintegration of a particular model of capital accumulation known as Fordism. Using the empirical context of the auto industry in Canada the paper analyses the development and subsequent breakdown of Fordism and the forms taken by the restructuring which has occurred in response to the crisis.     

SOME DEVELOPMENTS IN THE DIFFUSION PATTERNS OF HUTTERITE COLONIES

This paper describes some developments in the diffusion pattern of Hutterite colonies in North America. Today, there are more than 300 colonies distributed over the four western provinces of Canada and five states of the United States. The spatial behaviour of the three Hutterite clan-groups is compared, and responses by the sects to the repeal of the Alberta Communal Property Act in 1973 are assessed. Finally, changes in the rate of diffusion and the management of colony division are examined.
Cette communication décrit quelques développements dans la diffusion des colonies ďHutterites en Amérique du Nord. Aujourd'hui, il y a plus de 300 colonies dispersées dans les quatre provinces de ľoeust canadien et dans cinq états américains. Nous comparons le comportement spatial des trois groupes, ou clans, principaux ďHutterites et nous évaluons les réactions des sectes àľabrogation de la législation, de 1973, de la loi pourtant sur la possession en commun de propriétés Finalement. on examine le gérance de la division des colonies, et les changements dans leurs taux de diffusion.