A Segmentation Approach to Identify Underwater Dunes from Digital Bathymetric Models

The recognition of underwater dunes has a central role to ensure safe navigation. Indeed, the presence of these dynamic landforms on the seafloor represents a hazard for navigation, especially in navigation channels, and should be at least highlighted to avoid collision with vessels. This paper proposes a novel method dedicated to the segmentation of these landforms in the fluvio-marine context. Its originality relies on the use of a conceptual model in which dunes are characterized by three salient features, namely the crest line, the stoss trough, and the lee trough. The proposed segmentation implements the conceptual model by considering the DBM (digital bathymetric model) as the seafloor surface from which the dunes shall be segmented. A geomorphometric analysis of the seabed is conducted to identify the salient features of the dunes. It is followed by an OBIA (object-based image analysis) approach aiming to eliminate the pixel-based analysis of the seabed surface, forming objects to better describe the dunes present in the seafloor. To validate the segmentation method, more than 850 dunes were segmented in the fluvio-marine context of the Northern Traverse of the Saint-Lawrence river. A performance rate of nearly 92% of well segmented dunes (i.e., true positive) was achieved.

Surface Water Quality Differs between Functionally Similar Restored and Natural Wetlands of the Saint Lawrence River Valley in New York

We tested the hypothesis that upland wetland restorations provide the same quality of wetland, in terms of ecosystem services and biodiversity, as natural wetlands in the St. Lawrence River Valley. Water quality (pH, alkalinity, colored dissolved organic matter, phytoplankton community composition, chlorophyll-a, fecal coliform, total phosphorus, dissolved nitrate, turbidity, specific conductivity) in 17 natural and 45 restored wetlands was compared to determine whether wetland restoration provided similar physicochemical conditions as natural wetlands in the Saint Lawrence River Valley of northeastern New York State. Natural wetlands were more acidic, which was hypothesized to result from the avoidance of naturally acidic regions by farmers seeking to drain wetlands for crop and pasture use. Natural wetlands had significantly greater fecal coliform concentrations. Restored wetlands had significantly greater specific conductivity and related ions, and this is attributed to the creation of wetlands upon marine clay deposits. Other water quality indicators did not differ between restored and natural wetlands. These findings confirm other research at these same wetlands showing no substantial differences between restored and natural wetlands in major biotic indicators. Thus, we conclude that wetland restoration does result in wetlands that are functionally the same as the natural wetlands they were designed to replicate.

An Ostrich, a Backhoe and a few Ski-Doos: Tracking the Road Movie in Quebec and Beyond

This chapter focuses on the presence of the road movie in Quebec cinema. The province’s grands espaces, its famous snowy winters, and the ubiquitous presence of the Saint Lawrence River in the life of its citizens make for a propitious and particularly cinegenic exploration of mobility within the region. After tracing in a preliminary section the cinematic antecedents of Quebec’s contemporary road movies, three films are analysed separately: Stéphane Lafleur’s En terrains connus/Familiar Ground (2011), Philippe Falardeau’s Congorama (2006) and Denis Chouinard’s L’ange de goudron/Tar Angel (2001). The intent is to highlight some of the unique contours and distinct cinematic viewpoints of the francophone province, to assess the varying degrees to which the films’ Québécité takes centre stage, and to ponder Quebec cinema’s place within the larger cinéma-monde category.

The Atlantic Prehistory of Private International Law: Trading Companies of the New World and the Pursuit of Restitution in England and France, 1613–43

This article concerns itself with the kind of legal conflicts that broke out in the Atlantic New World between merchant interests from different parts of Europe. Case studies are made of two disputes: one between Samuel Argall of the Virginia Company and a factor on behalf of Antoinette de Pons at the Île des Monts-Déserts, and the other between the Compagnie de Caën and the Kirke brothers at the Saint Lawrence River. Together, these case studies reveal how important it was for merchant interests to have resident ambassadors and state officials advancing their interests in England and France. Procedural difficulties and jurisdictional uncertainty often impeded the road to redress. Additionally, this article suggests that the peacetime reckoning of events associated with warfare provided an optimal opportunity for disaffected private actors to have their claims for redress recognised. The extent to which private overtures for restitution relied upon public acts of diplomacy reveals some of the reasons why it is not possible to date the origins of private international law before the long nineteenth century. Rather we might profitably identify, in events such as these, the prehistory of private international law.

What Caused the Ongoing Flooding on Lake Ontario?

The floodwaters have also affected residents downstream along the Saint Lawrence River. Although politicians quickly blamed regulations, scientists say it was a perfect storm of natural factors.

ESTIMATING EULER POLE PARAMETERS FOR EASTERN CANADA USING GPS VELOCITIES

Eastern Canada is characterized by many intraplate earthquakes mostly concentrated along the Saint Lawrence River and Ottawa River valleys. After the rigid plate rotation of North America, the glacial isostatic adjustment (GIA) is by far the largest source of geophysical signal in eastern Canada. We estimate a set of Euler pole parameters for this area using a velocity field of 19 continuously operating GPS stations out of 112, and show that they are different from the overall rotation of the North American plate. This difference potentially reflects local stresses in this seismic region, and the difference in intraplate velocities between the two flanks of the Saint Lawrence River valley accumulate stress along the river.