Sunday, 9 January 2005
Using Climatological and geological history to develop a physical model that describes changes in stream morphology in the upper Dearborn river.
In the summer of 2004, eleven high school students from State College Area High School conducted field research in the Dearborn river valley in the Bob Marshall Wilderness Area of Montana. The focus was on the geomorphology of the area and how changes over time may have influenced the ecology of the river valley. Factors such as the raparian vegetation, soil environment, and the physical characteristics of the river valley were studied and interpreted to provide background to enable interpretation as to how geological and climatological factors influenced change. The river valley at the study site was approximately 200 meters wide, cobbles strewn near the channel with vegetative domains extending north and south. Observations indicated a diversity of plant regimes initiating a transect across the valley floor for purposes of completing a survey to determine if secession could provide relative aging of chaotic events. Efforts were made to determine the plant distributions, soil types and properties to achieve the above goal. The area was mapped in order to support the vegetative studies. Observations from altitudes approximately 500 meters above the flood plain indicated a chaotic and dynamically changing stream channel. Data has been gathered for the purposes of developing a brief geologic history of this changing environment. Climatology data, fire history, and past geologic history are being reviewed to achieve this goal. This paper will present these findings and possibly a completed map showing the historical changes in this section of the river valley.