Environmental Science: Watersheds and Runoff Pollution Worksheet

Question 1

Define a watershed in your own words. Include where the water in a watershed eventually goes.

Accepted Answer

A watershed is an area of land where all the water drains to the same stream, river, lake, wetland, or ocean. Water moves downhill through the watershed and eventually collects in a common body of water.

Question 2

A school parking lot, soccer field, roof, and garden all drain toward the same creek. Are these areas part of the same watershed? Explain your answer.

Accepted Answer

Yes, these areas are part of the same watershed because rainwater from all of them drains toward the same creek. A watershed includes all land that sends water to the same water body.

Question 3

List three pollutants that stormwater runoff can carry from streets or yards into nearby streams.

Accepted Answer

Stormwater runoff can carry pollutants such as motor oil, fertilizer, pesticides, pet waste, road salt, soil, and trash into nearby streams. Any three of these examples are reasonable.

Question 4

Explain why paved surfaces such as roads and parking lots can increase runoff compared with forests or grassy areas.

Accepted Answer

Paved surfaces increase runoff because they do not let much water soak into the ground. Forests and grassy areas absorb more rainwater through soil and plant roots, so less water flows over the surface.

Question 5

During a storm, rain falls on a farm field that has recently been fertilized. Describe how the fertilizer could affect a nearby pond if it is washed into the water.

Accepted Answer

If fertilizer is washed into a pond, it can add extra nutrients such as nitrogen and phosphorus. These nutrients can cause algae to grow quickly, which may reduce oxygen in the water and harm fish and other organisms.

Question 6

A student says, "Only factories cause water pollution." Write a response that corrects this idea using runoff pollution as evidence.

Accepted Answer

Factories can cause water pollution, but they are not the only source. Runoff from neighborhoods, farms, roads, lawns, and construction sites can carry pollutants into waterways, so everyday activities can also affect water quality.

Question 7

Look at this situation: A construction site has bare soil next to a stream. Heavy rain is expected tomorrow. What pollution problem could happen, and what is one way to prevent it?

Accepted Answer

Heavy rain could wash loose soil into the stream, causing sediment pollution. One way to prevent it is to use silt fences, straw barriers, ground cover, or other erosion controls to keep soil from leaving the site.

Question 8

Describe the difference between point source pollution and nonpoint source pollution. Give one example of each.

Accepted Answer

Point source pollution comes from one clear, identifiable source, such as a pipe releasing wastewater. Nonpoint source pollution comes from many spread-out sources, such as fertilizer and oil washed off land by stormwater runoff.

Question 9

A neighborhood wants to reduce runoff pollution before it reaches a river. Choose two actions from this list and explain how each one helps: planting rain gardens, picking up pet waste, using less fertilizer, sweeping driveways instead of hosing them, installing rain barrels.

Accepted Answer

Planting rain gardens helps because they absorb runoff and filter some pollutants before water reaches the river. Picking up pet waste helps because it keeps bacteria and extra nutrients from being washed into storm drains and waterways. Other listed choices can also be correct if the explanation shows how they reduce runoff or pollution.

Question 10

A stream becomes muddy after every rainstorm. What does the muddy water suggest about the watershed, and why can this be harmful to aquatic life?

Accepted Answer

Muddy water suggests that soil is being eroded and carried into the stream as sediment. This can be harmful because sediment can block sunlight, cover fish eggs and habitats, and make it harder for some organisms to breathe or feed.

Question 11

Use the diagram idea to trace the path of one drop of rain from a hilltop to a lake. Include at least three steps in the path.

Accepted Answer

A drop of rain may fall on a hilltop, flow downhill across the land, enter a small stream, join a larger river, and then reach a lake. The exact path can vary, but it should follow gravity through connected parts of the watershed.

Question 12

A town plans to build a new shopping center near a creek. Identify two design choices that could reduce runoff pollution from the site and explain why they would help.

Accepted Answer

The town could use permeable pavement because it lets more water soak into the ground instead of running off quickly. The town could also add vegetated buffer strips or rain gardens near the creek because plants and soil can slow runoff, trap sediment, and filter some pollutants.

Environmental Science: Watersheds and Runoff Pollution

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