1/19/2018 If a Woodchuck Could Chuck Wood If a Woodchuck Could Chuck Wood The easiest way to get to the creek behind the geology museum is shown below. The red circle indicates the entrance. The yellow circle indicates the geology museum. 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 email address (clemsongeopaths@g.clemson.edu) will be recorded when you submit this form. Not clemsongeopaths? Sign out * Required 1. Last Name, First Name * Entrance to Creek What causes stream erosion and deposition? River and stream channels tend to change shape over time due to the effects of the energy of running water interacting with the stream bed and banks. Because running water generates a certain amount of energy (proportional to its velocity), streams are able to pick up and transport sediment. The higher the velocity, the larger the sediment size that can be transported. When stream energy increases, more sediment can be picked up (erosion) when stream energy decreases, sediment is left behind (deposition). It takes a unique and very unusual set of circumstances to create a perfectly straight stream channel. In most cases, the channel winds back and forth across the landscape in a 'meandering' pattern. At each bend, the outer bank of the meander experiences higher energy stream flow which causes erosion. The inner bank experiences lower energy stream flow which causes deposition of sediment. Areas of Erosion and Deposition in a Stream https://docs.google.com/forms/d/1w7h-9ytz304eaqowtnqxxb1znxiubaqnskfga8dqcrs/edit 1/6
Examine the study area carefully and locate meanders, point bars (areas of sediment deposition) and cut banks (areas where erosion is occurring). Pay special attention to which side of the stream channel has the highest flow velocity at a meander bend and also within a straight segment of the stream. If you have trouble estimating the velocity, place a leaf or stick (not trash!) in different parts of the stream channel and observe the rate of flow. 2. Within a straight section of the stream channel, on what side of the channel does the water have its highest velocity? * The outside bank (cut bank) The inside bank (point bar) The center of the channel The velocity is the same everywhere. 3. Within a meander bend of the stream channel, on what side of the channel does the water have its highest velocity? * The outside bank (cut bank) The inside bank (point bar) The center of the channel The velocity is the same everywhere. Shifting River Profiles Imagine what the meander bend you are studying will look like in the future. How long do you think the cut bank can continue to erode and the point bar continue to fill in before the situation becomes unstable? https://docs.google.com/forms/d/1w7h-9ytz304eaqowtnqxxb1znxiubaqnskfga8dqcrs/edit 2/6
4. What do you think will eventually happen to this meander bend? * Cutting off a Meander Meandering streams like this one are common all over the world. Once meander bends are formed in a stream, the meanders continue to expand until the curvature becomes so extreme that the stream energy can no longer maintain the channel's shape. When this happens, the water cuts through the old point bar deposits to form a new straight channel. The old meander channel is either empty or sometimes retains water to form an oxbow lake. Forming an Oxbow Lake Landscapes Altered by Streams Some of the most beautiful landscapes are generated by sets of old river channels that scar the landscape along a river valley. In the satellite image below, old meander loops twist their way across the floodplain and document the history and changing profile of Rio Negro, one of the largest tributaries of the Amazon River in Brazil, South America. Meander scars of the Rio Negro https://docs.google.com/forms/d/1w7h-9ytz304eaqowtnqxxb1znxiubaqnskfga8dqcrs/edit 3/6
1/19/2018 If a Woodchuck Could Chuck Wood Changing Stream Patterns at Hunnicutt Creek Hunnicutt Creek is a much smaller stream than Rio Negro, and therefore the rate and extent of meander changes is also very different. Rio Negro has a much higher flow rate and higher stream velocity which results in much greater erosional power. The satellite image below shows the part of Hunnicutt Creek near where you are standing, and it is obvious there are no visible meander loop scars like Rio Negro visible on this image. https://docs.google.com/forms/d/1w7h-9ytz304eaqowtnqxxb1znxiubaqnskfga8dqcrs/edit 4/6
5. What could be one reason why meander scars like those of Rio Negro are not visible in the image of Hunnicutt Creek? * Activity Evaluation 6. I enjoyed this activity. * Strongly agree Agree Neutral Disagree Strongly disagree 7. I learned something from this activity. * Strongly agree Agree Neutral Disagree Strongly disagree 8. This activity made me want to learn more about this subject. * Strongly agree Agree Neutral Disagree Strongly disagree 9. Comments? (optional) Don't forget your geoselfie! https://docs.google.com/forms/d/1w7h-9ytz304eaqowtnqxxb1znxiubaqnskfga8dqcrs/edit 5/6
Take a picture of yourself with the cutbank and submit it via the link the follows after submission of this form. Powered by https://docs.google.com/forms/d/1w7h-9ytz304eaqowtnqxxb1znxiubaqnskfga8dqcrs/edit 6/6