Floods on the Minnesota River - Planning for the 100-Year Flood in St. Peter, Minnesota

Benjamin Laabs
SUNY Geneseo
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Students download and manipulate data from historical floods on the Minnesota River (could be done for any river) and use to establish a flood hazard zone for St. Peter, Minnesota. This lab was developed by colleagues and me at Gustavus Adolphus College.

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Introductory geology course for non-science majors. See the course profile page for Our Geologic Environment. The activity has also been used in introductory-level courses in environmental geology and natural disasters.

Skills and concepts that students must have mastered

Manipulating and analyzing data (historical flood records). Building and interpreting graphs. Topographic map interpretation, general knowledge of MS Excel.

How the activity is situated in the course

Stand-alone exercise done in lab. The lab can be accompanied by a pre-lab assignment to provide students with background information on flood discharge, records, and recognizing a flood plain on a topographic map.


Content/concepts goals for this activity

Recognize the relationship between flood stage and discharge, develop an understanding of flood recurrence interval and how it is calculated.

Higher order thinking skills goals for this activity

Data collection, manipulation and analysis. Application to a real-world setting. Critical evaluation of analytical methods.

Other skills goals for this activity

Common functions of MS Excel (data organization, formulating equations, graphing).

Description of the activity/assignment

Students explore the USGS water website to identify the location of stream gauges on the Minnesota River and the types of data that can be retrieved from the website. They determine which data to download based on the area of interest in the exercise (St. Peter, MN) and import historical flood data into MS Excel. The students use a spreadsheet to rank each flood and calculate a recurrence interval for a given flood, then estimate the discharge and stage of the 100-year flood in St. Peter, MN. The final task is to establish a flood hazard zone on a topographic map of the city of St. Peter. Note: this exercise can be applied to almost any non-dammed river with two or more USGS gaging stations on it. Go to http://water.usgs.gov and select your state from the pull-down menu to view an interactive map of your state's rivers and gaging station locations.

Determining whether students have met the goals

After completing the tasks, students answer a set of questions that probe what they've learned in the exercise. The questions reflect on the process of estimating the 100-year flood, ask students to consider the safety of familiar areas to flooding, and to consider their own safety from flooding. The questions are graded and the exercise is returned to students.

More information about assessment tools and techniques.

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Supporting references/URLs

Links: USGS Real-Time Water Data for Minnesota http://waterdata.usgs.gov/mn/nwis/rt ] USGS Water Projects homepage http://water.usgs.gov