The Prairie Pothole Region (PPR) is an area of the northern Great Plains and prairies that contains thousands of shallow wetlands known as potholes. The potholes are a result of glacier activity that ended about 10,000 years ago. The decaying ice sheet left behind depressions formed by the uneven deposition of till in ground moraines. These depressions are called potholes, kettles, or kettle lakes. Pothole wetlands are not connected by surface streams. They receive most of their water from spring snowmelt and groundwater inflow. Shorter duration wetland potholes are fed only by precipitation. More than half of the potholes have been drained and converted to agriculture. Those that remain, such as these at Sibley State Park, are extremely important habitats for migratory and breeding waterfowl and other wildlife. Half of the primary species of game ducks on the continent breed in wetland potholes!
To receive credit for this cache, please email the answers to these questions:
- From the spot you are standing, how many potholes do you see?
- Is there a stream connected to the pothole in front of you? How do you think this pothole filled with water?
- Do you think this pothole was formed by a glacier eroding a depression or pushing up hills to form a basin? Why?
- Estimate the distance across this pothole to the east side.