Glacial Deposition & Groundwater

Preparation: 

Students should have a sound background in porosity, permeability, and glacial geology before attempting this lesson.  In fact, this lesson is best suited as a synthesis of all students have learned about weathering, erosion, glacial geology, and ground water.

Contact the county department of planning to obtain the necessary maps. You may also reference a natural resources inventory of your county which may include some or all of these maps.  (See Additional Resources below.)

Engagement: 

Students should be given several minutes to read the excerpt from The Hudson: A History by Tom Lewis (found at the end of the student worksheet).  After the class has finished reading, the teacher should lead a discussion about the glacier that covered the Hudson valley during the last ice age.  Some questions that should be asked include, “How did the glacial ice impact the landscape of the Hudson Valley?” and “What are pieces of evidence left behind by the glacier that still exist today?” and finally, “How do these glacial features influence our lives today?”

Explore:

Students will begin the lesson by answering the preliminary questions using the Glacial Deposits Map for Dutchess County.  After they have completed the questions, each group of students will get a sample cup of each of the three glacial deposits and complete the lab activity, recording their results as they go.  After completing the activity, students should answer the activity questions based on their results.

            Students should next answer the questions in the predictions section of the lesson, basing their answers off of what they learned doing the activity and the Glacial Deposit Map for Dutchess County and Dutchess County Groundwater Occurrences Map.  If students have access to a computer in the classroom they should get on-line to begin their research, if not they should do so on their own.  As a conclusion, students will write a paragraph addressing what they learned by doing the lesson.

Optional modification: Another way to do the activity in this lab would be to use a modified sieve to more accurately measure permeability rates in each of the sediment samples.  To make the sieves one could use a small piece of PVC pipe and attach a piece of fine wire mesh to the bottom using a rubber band or other means of attachment.  The mesh should hold the sediment in and let the water drain out.  Students can use these sieves to time how long it takes for the water to drain from each sample and record their results in a table.  At the end of the activity students can compare results and come up with an average rate of permeability for each sample.

Explain:

Thousands of years ago an enormous ice sheet blanketed the Hudson Valley in what was called the Wisconsinan Glaciation.  The ice reshaped the land in its southern advance and northern retreat, leaving scars and signs that can still be discerned today.  We have these glaciers to thank for the landscape we enjoy so much today – from the beaches of Long Island, to the Hudson River and Catskills.  The glaciers played at least some role in each of their formations.

            Yet, the glaciers did more than just carve and create natural beauty.  They left behind sediments that play an integral role in our everyday lives.  These sediments are used in industrial, commercial, and residential ways that we often don’t even realize.  Some glacial sediments act as natural reservoirs of groundwater that can be tapped for human use.  We must be aware of these sediments’ locations and capabilities so that we can utilize them wisely and avoid contaminating a resource that is so important for sustaining communities here in the Hudson Valley.

Extension:

            Distribute “Geology and Your Backyard” worksheet.  Computers with good internet connection are required to complete the activity. This can be completed in class or given as homework.  Students apply their new map interpretation skills to look at natural resources, development, agricultural, and recreational opportunities in their community using the interactive web-based USGS Soil Survey mapper available here: https://www.nrcs.usda.gov/wps/portal/nrcs/site/soils/home/

Evaluate:

Students should be able to complete the activity and answer the questions appropriately.  Use the lab activity and extension questions to assess student understanding.

Additional Resources:

Dutchess County Natural Resources Inventory: Great background info and includes many relevant maps within each section: http://bit.ly/12r7Z8z

Selection of available Ulster County maps: http://bit.ly/10hIBkm

Westchester county Natural Resources Inventory maps: https://gis.westchestergov.com/apps/wcgis::natural-resources-inventory/explore

USGS Soil Survey mapper: https://www.nrcs.usda.gov/wps/portal/nrcs/site/soils/home/