Losing Streams vs. Gaining Streams  
Gaining streams are supplied with water from groundwater, and losing streams lose stream water to groundwater. Therefore gaining streams have water flowing year‐round or for extended periods such as wet seasons, whereas losing streams tend to have flow only in response to water‐input events like rainfall and otherwise have no flow. 
 
A. Watch the following MAGNET videos and answer the questions that follow.

 

 

 

Questions: 

  • Where does a losing stream typically occur?
  • Where does a gaining stream typically occur?
  • Why is that a predominantly groundwater fed stream often has a distinct water quality? 
  • Why is a groundwater dominant stream is often ecologically significant?
  • Why is that most of the streams in Michigan are gaining streams? 
  • Why is that many of the streams in Arizona or Nevada are losing streams?
  • Why is that understanding stream aquifer interaction, particularly the fluxes at the interface of streams and aquifers is critically important in water and ecological resources management? 

 

B. Develop a MAGNET model to explain the following interesting phenomenon, observed on a winter hydrogeology field trip: a sharp contrast in the flow condition between two stretches in a first order stream (creek) .  The stretch (F to I) was icy (mostly freezed), while the stretch from A to D was not. The turning point occurs at E.

 

Hydrogeological parameters are shown in the figure below. 


MAGNET/Modeling Hints

  • Use ‘Synthetic mode’ in MAGNET to create a model domain with the same dimensions as shown in the map
  • Overlay the provided SiteMap image file included in the problem description. Choose ‘Use Domain Extent’ to fit the image to the established domain size. 
  • Conceptualize the model as 1-layer aquifer with two-separate zones.Use a zones feature to assign specific parameters to the "orange" zone. The "green" zone can be parameterized with the domain attributes assigned in the Domain Attributes menu. 
  • Conceptualize the River and Stream features as constant head boundary conditions
  • Treat the domain boundaries as ‘no-flow’ boundaries.