Karst Topography & Spring-Fed Waterfalls

Grannis Creek falls is a moderate-sized, spring-fed stream in the karst topography of the Driftless Region of northeast Iowa. It is a dramatic example (for Iowa) of fractured bedrock creating cool spring fed streams characteristic of the Driftless landscape.  

• Where is the water coming from?

• How does the area of the spring differ from the surrounding landscape?
• Why is the spring area so different looking from the rest of the hillside? 
• How could events at the top of the hill impact the water we see coming out here?
• What needs to happen within the ground to allow this phenomena to occur? 
• Why are Iowa’s trout streams found in northeast Iowa? 
• How does this spring help keep trout alive, when they won’t survive in other parts of the state?

Students could:

• Begin investigation in geologic concepts including bedrock formations, chemical weathering of rocks, cave formation.
• Determine the relationship between karst topography and ground water.  

• Karst and Water Pollution Lesson Plans: PDF file produced by the state of Minnesota with several lessons about Karst topography. Many are written for grades 6-8, but they could be adapted for other levels. 
• Iowa Heritage Foundation | Get Hooked on Iowa's Trout: Short article describing the necessary habitats for trout and where those habitats can be found in Iowa. 
• Iowa DNR Trout Fishing Map: This interactive map shows the location of Iowa’s trout fishing streams located in northeast Iowa. A direct comparison of karst topographic areas.