Meander Migration in the Amazon Basin
Skills and concepts that students must have mastered
How the activity is situated in the course
Content/concepts goals for this activity
- Recognize geomorphic features of meandering rivers
- Appreciate erosion and depositional processes of meandering rivers
- Access online data sources of land use change
- Collect and analyze data to develop and test hypotheses about controls on channel migration rates
Higher order thinking skills goals for this activity
Other skills goals for this activity
Description and Teaching Materials
Students can work singly or as a group on this project. Actually, a group activity would be ideal, as hypothesis generation and testing is a challenging task, and collaboration broadens the scope of questions and approaches to testing hypothetical relationships.
Teaching Notes and Tips
- Image captures of stream location, with annotations of meandering stream features;
- Statement of hypotheses for why the Rio Ucayali is so much more active;
- Table of data collected as a means of testing the hypothesis;
- Analysis of the data;
- Summary of the test of the hypothesis.
- Figures should have descriptive titles and captions. Maps need directional indicator, scale, and annotations to highlight key features.
- Hypotheses must pose a relationship: for instance, the Rio Ucayali is more active because of a region of very active uplift just upstream. The test is evaluated based on how well it can be measured, and by the strength of the connection between the driving force and response of the river. For instance, higher uplift results in faster erosion, which forces rivers to carry more sediment, which leads to more sediment movement and storage, and thus more migration. One could determine if uplift is more rapid in this section of the Andes, based on earthquake activity, or other scientific publications on uplift rate, or simply the height and ruggedness of landscapes nearby. A comparative study could be implemented between adjacent streams. Deforestation could also be tested, based on estimates of disturbance over time, or just the presence of deforestation along the Rio Ucayali. Size of the river could play a role, if larger rivers carried more sediment and have greater power, they might be more prone to migrate. The causal relationships could be ranked as strong, moderate, weak, or absent a relationship.
- Data collection and analysis can be ranked according to excellent, good, fair, poor, unacceptable.
- Summary statement can be ranked according to excellent, good, fair, poor, unacceptable.
References and Resources
Earth Engine Views of Rivers and Land Use Around the World
Irrawaddy, braided river https://earthengine.google.org/#timelapse/v=20.37647,94.70562,7.924,latLng&t=2.79
Irrawaddy, distributary section https://earthengine.google.org/#timelapse/v=17.0467,95.56949,8.532,latLng&t=2.05
Brahmaputra, braided river https://earthengine.google.org/#timelapse/v=25.91176,89.59344,7.924,latLng&t=1.74
Amazon River, distributary section (STABLE!) https://earthengine.google.org/#timelapse/v=-1.06135,-51.26929,7.772,latLng&t=2.01
Arkansas-Mississippi River junction (both meandering rivers) https://earthengine.google.org/#timelapse/v=33.84989,-91.16697,9.748,latLng&t=0.00
Mine waste runoff effects on Ok Tedi River, Papua New Guinea https://earthengine.google.org/#timelapse/v=-5.23546,141.19554,10.356,latLng&t=1.06
Rio Madre de Dios in Bolivia, with effects of deforestation visible: https://earthengine.google.org/#timelapse/v=-12.80292,-70.45737,8.783,latLng&t=0.00
Google Earth Engine home: https://earthengine.google.org/#intro
Google Earth Engine, Global Forest Change, 2000-2012: http://earthenginepartners.appspot.com/science-2013-global-forest
Google Earth, focus on lat/lon: -8.50, -74.40. In the layers, enable Earthquakes, and under More, enable Water Body Outlines (shows which rivers have moved since the creation of this layer).
As an alternative or as additional information on earthquakes, see Earthquake size, location, and time for Peru (a Google Fusion Table), with data from NOAA's National Geophysical Data Center for damaging earthquakes, along with focal depths and magnitudes (http://www.ngdc.noaa.gov/nndc/struts/form?t=101650&s=1&d=1 ), and http://maps.ngdc.noaa.gov/viewers/hazards/?layers=2&extent=-180,70,180,-70# for a searchable map.
The Problem River
- Rio Ucayali in eastern Peru in Earth Engine: https://earthengine.google.org/#timelapse/v=-8.36311,-74.56119,5.892,latLng&t=0.57
Aalto, Rolf et al. "Episodic sediment accumulation on Amazonian flood plains influenced by El Nino/Southern Oscillation." Nature 425.6957 (2003): 493-497.
Aalto, Rolf, Thomas Dunne, and Jean Loup Guyot. "Geomorphic controls on Andean denudation rates." The Journal of Geology 114.1 (2006): 85-99.
Aalto, Rolf, et al. "Fluvial transport of sediment across a pristine tropical foreland basin: channel-flood plain interaction and episodic flood plain deposition." FJ Dyer, MC Thoms, & JM Olley. International Association of Hydrological Sciences, Publication 276 (2002): 339-344.
Aalto, Rolf, and Charles A Nittrouer. "210Pb geochronology of flood events in large tropical river systems." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 370.1966 (2012): 2040-2074.
Giardino, John R., and Adam Lee, 2011, Rates of Channel Migration on the Brazos River, http://www.twdb.texas.gov/publications/reports/contracted_reports/doc/0904830898_Brazos.pdf.
Howard, Alan, 2009, How to make a meandering river, Proc Natl Acad Sci U S A. Oct 13, 2009; 106(41): 17245â€“17246. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2762660/ . Check out the references in this article!!!
Safran, Elizabeth B et al. "Erosion rates driven by channel network incision in the Bolivian Andes." Earth Surface Processes and Landforms 30.8 (2005): 1007-1024. https://onlinelibrary.wiley.com/doi/full/10.1002/esp.1259