Identifying the Timing and Potential Causes of an Anoxic Reach of the North Branch Kawkawlin River, Michigan, USA. Nick Ross, Saginaw Valley State University , 7400 Bay Rd., University Center, MI 48710 email: nkross@svsu.edu Introduction • A section of the North Branch Kawkawlin River experiences seasonally slow-moving, swampy conditions. It is suspected that this is causing low dissolved oxygen levels and creating concerns for property owners as well as threatening fish populations.
Research Methods
Aerial Photographs
Aerial Photographs: 1938, 1969, 2012
• Suggest the reach existed in the 1840s, signifying natural rather than human causes. • One limitation of the study is that this exact reach in question was not discussed in the field notes.
• When did this reach become slow moving and anoxic? • What caused this reach to become slow moving and anoxic? • Property owners point to documents suggesting the river was not sluggish during the time of the logging industry.
• Suggest the reach existed as early as 1938, meaning that the implementation of modern large scale agriculture was not the cause.
Plat Maps Survey Notes
Research Questions
Study Area
Results
Field Data
Historical Plat Maps and Survey Notes
• Downstream from swampy stretch, there is loose rock in river channel and water is not present. This area could not be core sampled. • Loose rock acts as a natural dam. • Deep pooling in the river channel up river from the slow moving reach. • Organic sediment layer in areas where water has pooled in the river channel.
Origin of Rock Layer
Field Data Importance • Property owners are concerned with flooding and bacteria. • Property owners are concerned with maintaining the river as a recreational resource, since it is often used for boating and fishing. • Saginaw Bay Fish populations may be unable to use this reach of the river as a spawning area. • Many property owners call for dredging to solve these “unnatural” issues.
Acknowledgements I would like to thank Dr. Mohler, Assistant Professor of Geography for his support and supervision on this project, the Dow Student Research and Creativity Institute for providing funding to present this project at the AAG Annual Meeting, and the Saginaw Bay Environmental Science Institute for supporting the research itself.
• Deposits from the glacial advances during Michigan’s glacial periods are a possible explanation for the loose rocky material. • This also suggests that this may be the natural geomorphological state of this reach of the North Branch Kawkawlin river.