A River Runs Through It

Transcription

1 A River Runs Through It Once you find the geocache, click "Found It" on the Geocaching.com app and then read and answer the questions below. Make sure to return the cache to exactly the same place you found it for the next geocacher to find! Your address will be recorded when you submit this form. Not clemsongeopaths? Sign out * Required 1. Last Name, First Name * Clemson Without a Lake? Clemson's campus was not always bordered by a lake. The Seneca River used to run right through the lowland area that now contains the Rugby Field, Baseball Stadium, Track, and Practice Football Fields. Part of that river channel is still visible (for example, the section along the road you took to reach the Rowing Docks Parking Lot). The figure below is a topographic map that illustrates what the western portion of Clemson's campus looked like in Many changes have occurred since then, but most notably, Lake Hartwell did not exist in Lake Hartwell, and several other nearby reservoirs, were constructed by damming up rivers and flooding their valleys. Most reservoirs in South Carolina, including Lake Hartwell, were built to provide water for hydroelectric power generation and/or to provide recreation for local residents and tourists. Here is a picture a 1951 topographic map of the western half of Clemson's campus. The blue marker indicates your geocaching location. Creating Lake Hartwell In the early 1950s, a dam was built on the Savannah River along the Georgia/South Carolina State Line near Hartwell Georgia. The resulting reservoir, named Lake Hartwell, flooded the valleys of several tributary rivers, including the Seneca River near Clemson. The original plan was to flood all 1/5

2 areas below 660 feet in elevation, which would have impacted many of Clemson University's experimental agricultural fields and also put part of Clemson's Death Valley Football Stadium under water. To avoid this problem, two large earthen dams (usually referred to as 'dikes') were built to cut off the existing Seneca River Channel and keep the rising water off Clemson land, and a brand new channel for the Seneca River was cut through a lower section of land farther west of campus. Moving the Seneca River In the figure below, the two diversion dams are marked by brown bars; the red line represents the approximate path of the old river channel and the yellow line indicates the cut through path of the New Seneca River channel. Remnant Segments of the Seneca River 2/5

3 Evidence of the Old Seneca River You are standing on a fluvial terrace (a relatively flat area that used to be part of a floodplain of a river). Look around you to try and find evidence that the earth materials making up this terrace were once deposited by a river. 2. What evidence did you find that would support the hypothesis that a river once flowed past this spot? [Hint: What do rocks look like that have been in a river or stream for a long time?] Describe your 'evidence' below, and then take a geoselfie with your evidence to submit at the end of this form. * 3. Note that your geocaching location is NOT alongside the current river channel (as shown in the 1951 map). What do you think is the best explanation for this fluvial terrace being located so far away from the modern river channel? * River channels often change their course over time. Tectonic movements (such as earthquakes) have shifted land/water over time. These are not terrace deposits, but could have been shaped by other geologic processes not related to water. These are terrace deposits, but were dug from a different location and dumped here by humans. 3/5

4 4. Recall that the water in Lake Hartwell is at a higher elevation than the water in the Old Seneca River channel. How do you think the Old Seneca River water eventually gets into Lake Hartwell? (Note: if that didn't happen, the campus area around the old river channel would gradually fill up with water.) * Activity Evaluation 5. I enjoyed this activity. 6. I learned something from this activity. 7. This activity makes me want to learn more about this subject. 8. Comments? (optional) Don't forget your geoselfie! 4/5

5 Take a picture of yourself and the 'evidence' you found of an old river deposit and submit it upon completion of this form. Powered by 5/5