TeacherWS2015

Short Course on River Dynamics and Vegetation in the Arid West

Introduction

The topic of this short course is River Dynamics and Vegetation in the Arid West. The course includes lectures on a case-study of the Rio Puerco, New Mexico, on the theory of river water and sediment transport. Two handson components include notes on laboratory experiments and spreadsheets and numerical modeling experiments. This material was developed by CU researchers, Greg Tucker, Irina Overeem and Mariela Perignon and is geared toward secondary science teachers, with application to curriculum in earth science, physics and biology.

Topic

We share insights on river processes in the Western US. Lectures highlight the basic terminology and physics of water flow and sedimentation processes. The short course uses the Rio Puerco, New Mexico, to illustrate how river morphology can rapidly change, and looks at impacts of the introduction of the invasive tree species Tamarisk in the 1920s. At the turn of the 20th century the relatively small Rio Puerco delivered large amounts of sediment to the Rio Grande in New Mexico and threatened to rapidly decrease the lifetime of Elephant Butte Reservoir. Elephant Butte Reservoir provides New Mexico and Texas with critical storage of Rio Grande water for agricultural use. Scientist and engineers at the time proposed vegetation measures to manage the rapid erosion in the Rio Puerco channel and thus reduce the sediment load being drained into the Rio Grande. More recently, invasive species have been recognized as a threat to the natural floodplain ecosystem in the West. Large floods occurred in 2006 and again in 2013 (coincident with the floods in the Front Range of Colorado). Efforts to destroy Tamarisk have led again to dramatic changes in channel geometry and sedimentation during these floods. Thus, the Rio Puerco represents a unique natural experiment in the effects of long-term vegetation change on a dryland river system.

The material has notes on sandbox experiments and computer modeling that can be easily used in your own classrooms to learn about river dynamics and vegetation.

A course syllabus is posted here: File:Syllabus RiverVegetationDynamics.pdf

Reading for this Course

• Perignon, M. C., G. E. Tucker, E. R. Griffin, and J. M. Friedman (2013), Effects of riparian vegetation on topographic change during a large flood event, Rio Puerco, New Mexico, USA, J. Geophys. Res. Earth Surf., 118, 1193–1209, doi:10.1002/jgrf.20073.

Real-event Movies and Model Simulations on Dryland Rivers and Vegetation

More general movies relevant to the river procesess discussed:

• Look at sediment transport with a flashflood
  
• the expansion of dams and reservoirs worldwide
  

Movies and model simulations specific for the recent floods in the Rio Puerco:

• See how high the Rio Puerco flooded in 2013
  
• Community downstream experienced damage due to flooding of the Rio Puerco 2013
  
• The floodwater spilled over from the Rio Puerco arroyo
  

• Hydrodynamic model simulations of 2006 flood in Rio Puerco
  
• See how model predicts patterns of sedimentation and erosion due to the flood of 2006