36002 Topic: SCI 207 Our Dependence upon the Environment
Number of Pages: 2 (Double Spaced)
Number of sources: 3
Writing Style: APA
Type of document: Essay
Category: Environmental Issues
Language Style: English (U.S.)
Order Instructions: Attached
Week 1 – Assignment 1
Stream Morphology Laboratory
[WLO: 1] [CLOs: 1, 3, 5]
This lab enables you to construct a physical scale model of a stream system to help you understand how streams and rivers shape the landscape, and how human actions can affect river ecosystems. This lab is done with materials that you will need to supply; the list of items you will need to obtain is in the Stream Morphology Investigation ManualPreview the document.
Take the required photos and complete all parts of the assignment (calculations, data tables, etc.). On the “Lab Worksheet,” answer all of the questions in the “Lab Questions” section. Finally, transfer all of your answers and visual elements from the “Lab Worksheet” into the “Lab Report.” You will submit both the “Lab Report” and the “Lab Worksheet” to Waypoint.
Make sure to complete all of the following items before submission:
Before you begin the assignment, read the Stream Morphology Investigation ManualPreview the document and review The Scientific Method presentation video.
Complete Activity 1 and Activity 2 using the materials that you supply. Photograph each activity following these instructions:
When taking lab photos, you need to include in each image a strip of paper with your name and the date clearly written on it.
Complete all parts of the Week 1 Lab WorksheetPreview the document and answer all of the questions in the “Lab Questions” section.
Transfer your responses to the lab questions and the data tables and your photos from the “Lab Worksheet” into the Lab Report TemplatePreview the document.
Submit your completed “Lab Report” and “Lab Worksheet” through Waypoint.
Table of Contents
2 Overview 2 Outcomes
2 Time Requirements
10 Preparation 10 Activity 1
12 Activity 2
13 Disposal and Cleanup
14 Lab Worksheet
18 Lab Questions
Students will construct a physical scale model of a stream system to help understand how streams and rivers shape the solid earth (i.e., the landscape). Students will perform several experiments
to determine streamflow properties under different conditions. They will apply the scientific method, testing their own scenarios regarding human impacts on river systems.
• Design a stream table model to analyze the different characteristics of streamflow.
• Explain the effects of watersheds on the surrounding environment in terms of the biology, water quality, and economic importance of streams.
• Identify different stream features based on their geological formation due to erosion and deposition.
• Develop an experiment to test how human actions can modify stream morphology in ways that may, in turn, impact riparian ecosystems.
Preparation ……………………………………………………………. 5 minutes, then let sit overnight Activity 1: Creating a Stream Table ………………………….. 60 minutes
Activity 2: Scientific Method: Modeling Human Impacts
on Stream Ecosystems……………………………. 45 minutes
equipment goggles g
follow photograph stopwatch
link to video
results and submit
required on flammable toxic environment health hazard
Made ADA compliant by NetCentric Technologies using the CommonLook® software
2 Carolina Distance Learning
A watershed is an area of land that drains
any form of precipitation into the earth’s water bodies (see Figure 1). The entire land area that forms this connection of atmospheric water to the water on Earth, whether it is rain flowing into a lake or snow soaking into the groundwater, is considered a watershed.
Water covers approximately 70% of the earth’s surface. However, about two-thirds of all water is impaired to some degree, with less than
1% being accessible, consumable freshwater. Keeping watersheds pristine is the leading method for providing clean drinking water to communities, and it is a high priority worldwide. However, with increased development and people flocking toward waterfront regions to live, downstream communities are becoming increasingly polluted every day.
From small streams to large rivers (hereafter considered “streams”), streamflow is a vital part of understanding the formation of water and landmasses within a watershed. Understanding the flow of a stream can help to determine when and how much water reaches other areas of a watershed. For example, one of the leading causes of pollution in most waterways across the United States is excessive nutrient and sediment overloading from runoff from
the landmasses surrounding these waterways. Nutrients such as phosphorus and nitrogen
are prevalent in fertilizers that wash off lawns and farms into surrounding sewer and water systems. This process can cause the overproduction of algae, which are further degraded
by bacteria. These bacteria then take up the surrounding oxygen for respiration and kill multiple plants and organisms. A comprehensive understanding of the interaction between streams and the land as they move downstream to other areas of a watershed can help prevent pollution. One example is to build a riparian buffer—a group of plants grown along parts of a stream bank that are able to trap pollutants and absorb excess nutrients; this lessens the effects of nutrient overloading in the streambed. (A riparian ecosystem is one that includes a stream and the life along its banks.)
Sediment, which is easily moved by bodies of water, has a negative effect on water quality. It can clog fish gills and cause suffocation, and the water quality can be impaired by becoming very cloudy because of high sediment flow. This can create problems for natural vegetation growth
by obstructing light and can prevent animals
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from visibly finding their prey. Erosion also has considerable effects on stream health. Erosion, or the moving of material (soil, rock, or sand) from the earth to another location, is caused by actions such as physical and chemical weathering (see Figure 2). These processes loosen rocks and other materials and can move these sediments to other locations through bodies
of water. Once these particles reach their final destination, they are considered to be deposited. Deposition is also an important process because where the sediment particles end up can greatly impact the shape of the land and how water is distributed throughout the system (see Figure 2). Erosion and deposition can occur multiple times along the length of a stream and can vary because of extreme weather, such
as flooding or high wind. Over time, these two processes can completely reshape an area,
causing the topography, or physical features, of an entire watershed to be altered. Depending on weather conditions, a streambed can be altered quite quickly. Faster moving water tends to erode more sediment than it deposits. Deposition usually occurs in slower moving water. With less force acting on the sediment, it falls out
of suspension and builds upon the bottom or sides of the streambed.
Sediments are deposited throughout the length of a stream as bars, generally in the middle of
a channel, or as floodplains, which are more ridgelike areas of land along the edges of the stream. Bars generally consist of gravel or sand-size particles, whereas floodplains are made of more fine-grained material. Deltas (see Figure
3) and alluvial fans (see Figure 4) are sediment deposits that occur because of flowing water
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4 Carolina Distance Learning
the water moving in the stream) are both vital to the shaping of streambeds. Within stream ecosystems, there are microhabitats (smaller habitats making up larger habitats) that have different discharges and velocities. The type
of microhabitat depends on the width of that part of the stream, the shape of the streambed, and many other physical factors. In areas that contain rifles, water quickly splashes over shallow, rocky areas, which are easily observed in sunny areas (see Figure 5). Deeper pools of slower moving water also form on the outside of the bends of the streams, as shown in Figure 5. Runs, which are deeper than rifles but have a moderate current, connect riffles and pools throughout the stream. The source of a stream and are considered more permanent structures because of their longevity. They are both fan-shaped accumulations of sediment that form when the stream shape changes. Deltas form in continuous, flowing water at the mouth of streams, whereas alluvial fans only form in streams that flow intermittently (when it rains or when the snow melts). Alluvial fans are usually composed of larger particles and will form in canyons and valleys as water accumulates in these regions. The fan shape of both deposits is easy to spot from a distance because they are formed due to the sand settling out on the bottom of the streams.