Stream Morphology Lab: Understanding Streams and Erosion Effects

Stream Morphology Lab Report Danny Tran 10 July 2023

1 Abstract This lab provides an understanding of stream systems and impacts of these systems on the surrounding environment. The experiment on stream morphology aims to enhance our comprehension of how streams and rivers shape and transform geological landscapes by examining various flow properties. Stream tables are employed under various heights and conditions to calculate the five characteristics of a stream, enabling observation of the sediment's erosion and deposition patterns. Both activities yielded findings indicating fluctuations in velocity and discharge in relation to table height and the presence of obstacles. Furthermore, they shed light on the modifications occurring in the landscape due to sinuosity and physical barriers. These experimental investigations serve the purpose of studying streams and microhabitats while also contributing to the improved management of watersheds (Recycle Nation, 2020). Introduction Streams and rivers significantly impact the environment, making it crucial to study their flow properties and geological landscape alterations (Wiens, 2002). This lab involves constructing a scaled stream model, conducting experiments, and applying the scientific method to understand the system's impact. By analyzing stream characteristics, identifying geological formations, and examining watershed effects, this lab enhances our understanding of stream systems and their environmental influence (Recycle Nation, 2020). Additionally, it allows us to © 2016 Carolina Biological Supply Company

2 predict and improve water management practices, ensuring cleaner accessible water resources in the face of increasing development and pollution (Beschta & Platts, 1986). Materials and Methods Materials  Stopwatch  Sand  Foam cup  Two books  Plastic cup  Paper clip  Rules  Tap water.  Two plastic bags Preparation steps 1. Use the foam try and spread the sand evenly on the tray. 2. Start pouring water on the sand and saturate it. Then rub the sand flat on the foam tray and let the sand dry overnight. 3. Make a hole in the foam cup 1 cm above the surface of the cup using paper clip. Activity-1 © 2016 Carolina Biological Supply Company

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3 1. Place the books in plastic bags and position the 4cm thick book slightly elevated at one end of the tray, causing it to tilt. 2. Position the foam cup at the tray's top and gradually fill it with water using the plastic cup. 3. As water fills the foam cup, it will trickle out, forming a stream. Stop adding water once a small stream flow is established. 4. Carefully observe and sketch the stream's appearance, identifying areas of erosion and deposition. 5. Record stream values and data in the table. (To measure travel time, tearing a small piece of foam from the cup and time how long it takes to float down the stream.) 6. Repeat steps 5-7 for two more trials. 7. Repeat steps 5-8 using the 2 cm thick book. Activity-2 1. Create a small "dam" by arranging a line of closely packed gravel across the tray, approximately one-fourth of the way down. 2. Prepare the books by wrapping them in plastic bags, then position the 4cm thick book slightly beneath one end of the tray, causing the tray to tilt at an angle. 3. Place the foam cup at the tray's top and slowly fill it with water using the plastic cup. 4. As water fills the foam cup, it will trickle out, forming a stream. Cease adding water once a small stream flow begins. 5. Carefully observe and sketch the stream's appearance, noting areas of erosion and deposition. © 2016 Carolina Biological Supply Company

4 6. Calculate stream values and record data in the table. 7. Repeat steps 3-5 for two additional trials. Calculations The calculations are performed based on these formulas provided below. Velocity is calculated by dividing the distance traveled by the time it took for travel. Velocity = Travelled Distance time ¿ travelthe distance ¿ Sinuosity is determined by dividing the curvy distance by the straight distance. Sinuosity = Curved Distance Straight distance Discharge is obtained by multiplying the velocity by the cross-sectional area. Discharge = Cross-sectional Area x Velocity Relief is calculated by subtracting the lowest elevation from the highest elevation. Relief = Highest Elevation – Lowest Elevation Gradient is determined by dividing the relief by the total distance. Gradient = Relief totaldistance Activity 1: Data Table 1 © 2016 Carolina Biological Supply Company

5 Table 1. Activity-1 Data Table Trial Velocit y (cm/s) Discharg e (cm 3 /s) Sinuosit y Relief (cm) Gradient (cm) 4 cm 1 2.67 0.40 1.58 3.1 0.16 2 3.56 1.42 1.0 3.3 3.3 3 4.86 0.97 1.47 2.5 0.1 2 cm 1 0.56 0.084 0.89 1.5 0.05 2 0.75 0.75 1.1 1.5 0.04 3 0.94 0.093 1.12 1.5 0.05 Activity 1: Photo © 2016 Carolina Biological Supply Company

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6 Activity 2: Data Table 2 Variable changed: One variable that was altered is the placement of a rock dam, positioned approximately one-fourth of the way down from the top of the tray. © 2016 Carolina Biological Supply Company

7 Table 2. Activity-2 Data Table Trial Velocit y (cm/s) Discharg e (cm 3 /s) Sinuosit y Relief (cm) Gradient (cm) 4 cm Book 1 0.03 0.0045 1 5 5 2 0.04 0.0008 1.09 5 0.21 3 0.05 0.0075 1 5 5 Activity 2: Photo © 2016 Carolina Biological Supply Company

8 Conclusion The experiment conducted with the stream table provided valuable insights into the dynamic nature of rivers and how they shape the surrounding landscape. Key characteristics of rivers, including gradient, velocity, discharge, sinuosity, and relief, were observed to have a direct impact on the physical changes that occur. In the first activity, it was observed that higher gradients and relief resulted in increased velocity and discharge. Sinuosity, on the other hand, played a role in understanding how sediment is deposited and eroded along meandering river bends. © 2016 Carolina Biological Supply Company

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9 The second activity demonstrated the influence of barriers, such as dams, on the velocity and discharge of the stream, which in turn affected the physical shape and characteristics of the stream. For example, the presence of a rock dam caused a significant decrease in velocity, leading to branching of the stream in various directions. These experiments using stream tables provide valuable insights into how streams shape the Earth's surface and the microhabitats that exist within different river systems. By understanding the influence of features like plants and dams, we can effectively manage watersheds in different areas. References Beschta, R. L., & Platts, W. S. (1986). Morphological Features Of Small Streams: Significance And Function 1. JAWRA Journal of the American Water Resources Association , 22 (3), 369–379. Luell, S. K., Winston, R. J., & Hunt, W. F. (2021). Monitoring the water quality benefits of a triangular swale treating a highway runoff. Journal of Sustainable Water in the Built Environment , 7 (1), 5020004. Recycle Nation. (2020). Stream Morphology – RecycleNation . https://recyclenation.com/green- glossary/stream-morphology/ Wiens, J. A. (2002). Riverine landscapes: taking landscape ecology into the water. Freshwater © 2016 Carolina Biological Supply Company

11 Post-Lab Questions 1. If a short river has a relief of 3 meters and a much longer river has the same relief, how is the gradient affected? Why? The gradient of a shorter river will be more pronounced and steeper as compared to that of a much longer river. This disparity arises from the shorter river experiencing a more rapid drop in elevation, while the longer river, with a gentler slope, gradually reaches the same gradient. 2. What variable did you alter in Activity 2? Did you correctly predict your hypothesis? If not, could there have been any outside factors that could have caused your results to turn out the way they did? In activity 2, I constructed a small rock dam near the top of the tray, covering it with sand. My hypothesis was that the presence of a strong barricade at the top would result in slower water velocity compared to when there was no dam. The actual observations partially supported my hypothesis. The water velocity decreased only upon entering the barricade and as it trickled out from the other side. However, measuring the velocity was challenging due to the barrier obstructing the small foam. I believe there were no external factors influencing the outcomes of the second activity. One aspect for improvement was not anticipating the water to create multiple © 2016 Carolina Biological Supply Company

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12 streams upon exiting the barricade. Therefore, my measurements were taken from the initial steady stream that emerged beyond the barrier. 3. Jose walked down to the stream behind his house. Over the past few months, he has noticed that the water has become increasingly cloudy since an industrial waste company built their headquarters upstream. He also noticed much less aquatic life in and around the area. Write a testable hypothesis that could be used to help determine what issues could be affecting the water downstream from the industrial waste company and causing the conditions Jose has been observing. In the scenario where the water quality is favorable upstream from the company's headquarters, it can be inferred that the building itself is causing pollution in the water downstream. 4. Identify at least two reasons why calculating velocity, discharge, gradient, relief, and sinuosity can be useful. What can we learn from these measurements about the stream and its surrounding environment? The measurements obtained through the Stream Morphology Investigation provide valuable insights into the physical characteristics, properties, and overall health of a stream. Velocity, for example, offers information about the habitat present in water that moves at different speeds. Slower-moving water, creating pools, may be conducive to finding salamanders and young fish, whereas faster-moving water may support different species. © 2016 Carolina Biological Supply Company

13 Additionally, discharge measurements can help in predicting the potential occurrence of flooding. 5. The process of erosion and deposition can create microhabitats. Macroinvertebrates are small aquatic organisms, like worms and mollusks, that can be found in these microhabitats. Explain why researchers may want to know what types of macroinvertebrates are living in those stream microhabitats. What can that tell them about the stream? Macroinvertebrates serve as crucial indicators of a stream's health due to their limited tolerance for varying pollution levels. They can be categorized into three groups based on their tolerance levels, with the first group being most sensitive and requiring the cleanest water conditions. For example, mayflies thrive in exceptionally pristine water with high dissolved oxygen levels and demonstrate sensitivity to changes in water quality. On the other hand, aquatic worms can survive in environments with low dissolved oxygen and poorer water quality (Luell et al., 2021). © 2016 Carolina Biological Supply Company

ENV 220 Stream Morphology Lab Report

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