| Summary: | National audience Since its establishment at the mouth of the Umiujaq River in 1984, the village of the same name has developed, and notable features of socio-environmental evolution have become apparent. After a characterization of the hydrological system on the basis of photo-interpretation of aerial views and satellite images (via GoogleEarth), environmental changes on the whole watershed appear. First of all, thermokarst processes, which, without being quantitatively evaluated in terms of water and sediment flows, release both mineral suspended matter and organic matter into the surface waters, via a partially underground circulation. Vegetation cover has also changed significantly since 1984, with vegetated area increasing clearly since that date. The filtering role of the vegetation on sediment transfers is likely, limiting the possibilities of direct connection from the slopes on either side of the main bed. However, an example of a landslide, seasonally activated since at least 2013, highlights the potential connection between the slopes and the stream. The summer field season allowed for in situ characterization of the different compartments of the watershed, and qualification of the stream bottom in the downstream segment. The question arises, however, whether the stream has the competence for bottom transport, or whether it flows over inheritances. Depuis la sédentarisation de la population à l’embouchure de la rivière d’Umiujaq, dans le village du même nom qui s’est développé depuis 1984, des traits notoires d’évolution socio-environnementaux sont apparus clairement. Après une caractérisation du système hydrologique sur la base de photo-interprétation de vues aériennes et images satellitaires (via GoogleEarth), des changements environnementaux sur l’ensemble du bassin-versant apparaissent. Il s’agit d’abord de processus thermokarstiques qui, sans que cela soit encore quantitativement évalué en termes de flux hydrique et sédimentaire, relâchent à la fois des matières en suspension et de la matière ...
|
|---|