Teacher & Student Materials > Quenching a Thirsty Planet
Where does water go once it is used?
3 hours
After water is used, it either will be treated at a wastewater treatment plant (such as sewage) or it will runoff into the ocean, carrying with it potentially harmful pollutants.
Students will investigate the ways that increased agricultural and residential areas affect the water supply by analyzing public data related to runoff pollutants and completing a computer simulation modeling the relationship between rainfall and runoff in a variety of areas (developed – undeveloped).
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Materials: 3.2 Where doe the water go once it is used?
Show the graphic of how North Carolina uses its water, and ask students to summarize the data. For North Carolina, students should notice that the largest amount of water is used for thermoelectric energy, the average amount of water is used for public supply, domestic, industrial, and irrigation. Livestock and mining are the least used water sectors in North Carolina.
The video on slide 3 introduces sewage systems. Although it is engaging, it can be skipped to save time.
Materials: 3.2 Does More Rainfall Mean We Have More Water? & a device to access website
Although our aquifers recharge through rainfall, it is not a guarantee (in fact, it is far from it) that all rainfall will infiltrate underground. Some conditions lend to better infiltration than others.
Review major findings from the simulation
This is an excellent opportunity to arrange with your school’s extension agent to get an expert on land use in your specific area.
In addition to thinking about how severe weather storms are caused, pose questions throughout this section about how runoff is different based on the conditions explored in the previous activity.
If weather is not a major part of your curriculum, these slides can be skipped. If a particular type of severe weather is common in your area, we recommend focusing on that. For instance, on the Southeast Coast we recommend focusing on hurricanes.
In the next activity, students will look at agricultural pollutants, so use this time to make sure they understand the ways that water will runoff in rural areas that are irrigated. As you discuss irrigation, remind students that irrigated water mostly comes from groundwater.
Flood and furrow are two techniques for irrigating land and crops. Drip/micro-irrigation and spray/sprinkler irrigation are other common methods of irrigating land. If this is an interesting topic to your students, have students divide into groups to research one of the irrigation methods. Tell them to be prepared to answer the following questions:
Materials: 3.2 Agriculture & Home Pollution Worksheet
This activity requires students to read a short (< 1 page) passage on the consequences of excess nitrogen and phosphorus in water systems. The students will answer questions using the provided graphs and their previous knowledge from the High Plains Aquifer lesson. The images are in color, so it might be helpful if students have access to a digital copy for analysis.
Questions 7 & 8 are challenging. They might be better suited for honors classes and be considered bonus questions in general population classes.
Although an example is provided on slide 22, feel free to use a student’s model instead. Lead the class through a discussion using the following questions:
Students will revise their water cycle models for a third time. They will work with a group to add a highly developed area and an agricultural area to their models. As a group, they need to answer the two questions on the slide as a formative assessment.
Feel free to make this an exit ticket, a group discussion, or an individual journal entry.
Small group discussion
Eutrophication is a process that occurs when excess nutrients, such as nitrogen and phosphorus, enter a water body, leading to an overgrowth of aquatic plants and algae. This can have detrimental effects on the ecosystem and water quality.
In terms of agriculture, the excessive use of fertilizers is a significant factor. Farmers often apply fertilizers to enhance crop growth, but if these nutrients are not absorbed by plants entirely, they can be washed away by rainwater or irrigation runoff and find their way into nearby rivers, lakes, or streams. Similarly, when manure from livestock operations is not properly managed, it can be a significant source of nutrients in water bodies. Moreover, poor land management practices, such as inadequate erosion control measures, can result in sedimentation in waterways, further exacerbating eutrophication.
Home practices can also play a role in eutrophication. The excessive use of fertilizers on lawns and gardens can lead to nutrient runoff during rainfall, similar to agricultural runoff. Additionally, the use of certain cleaning products and the improper disposal of household chemicals can introduce phosphates and other pollutants into the water supply when washed down drains. Similarly, untreated sewage or poorly functioning septic systems can release nutrients into nearby water bodies, contributing to eutrophication.
Depending on your students, access to technology, and curricular priorities, there are several ways to implement this lesson.
For three 45-60 minutes class periods, we recommend:
| Day | Activity | Potential Modifications |
|---|---|---|
| Day 1 | Class Discussion (slides 1-4) 3.2 Does More Rainfall Mean We Have More Water? | 3.2 Does More Rainfall Mean We Have More Water? requires access to a device and internet. If students do not readily have that available at home, it should be completed in class. |
| Day 2 | Severe Weather (Slides 6-16) Irrigation & Agriculture (17-20) 3.2 Agriculture & Home Pollution Worksheet | If severe weather is not a priority, skip slides 6-16. 3.2 Agriculture & Home Pollution Worksheet has about a page of reading. Students might do better working in partners. |
| Day 3 | Finish 3.2 Agriculture & Home Pollution Worksheet Revise Water Cycle Models | The final versions of the water cycle models should be significantly more sophisticated that the first ones. For example see Water Cycle Models |
If students are successful independent workers, these activities can be organized into do-at-your-own-pace checklists that students show mastery by completing a revised water cycle model.
If students have observed changes in water levels of local bodies of water or heavy rainfall that caused flooding in their neighborhoods, teachers can use these experiences to facilitate learning about runoff and pollution.
In rural areas, backroads students take to get to school can flood causing them to miss school. However, teachers can build on these experiences by pointing out how heavy rainfall can have significant impacts on our daily lives. It’s not just about the inconvenience of getting to school, but it also relates to the way water interacts with the environment. Ask students to recall other changes to their surroundings during that time. If water levels were changing, tie that to infiltration and runoff as well. Heavy rainfall can cause water bodies like lakes to rise rapidly. When it rains heavily, the excess water doesn’t always get absorbed into the ground as quickly as it falls. Instead, it can flow over the surface, leading to more runoff. Sometimes, when there’s too much water, it can put pressure on the lake or river, potentially leading to flooding.
Students might also come with previous experiences of lakes being drained to prevent flooding which is an excellent way to tie back to the Hoover Dam and ways to manage water. Cities have to manage their water differently because runoff is experienced differently due to the different types of surfaces.
By tying in these observations and the significance of water management projects like the Hoover Dam, teachers can help students understand the importance of balancing water resources, addressing flooding risks, and providing a sustainable water supply for various human needs, including agriculture.
Using students’ ideas helps them to connect their observations of local water bodies, such as changes in water levels and discussions about lake draining, to broader concepts of water management and the significance of large-scale infrastructure projects like the Hoover Dam in addressing these challenges.
Analyzing and Interpreting Data is an important skill across many disciplines, not only science. In the 3.2 Agriculture & Home Pollution Worksheet, students will have the opportunity to develop and apply their skills in analyzing and interpreting data. The worksheet focuses on visual data, such as maps and graphical representations, which are commonly used tools in various disciplines to extract meaningful information from data sets. By engaging with these forms of data, students can enhance their ability to identify patterns, trends, and significant features in the context of agriculture and home pollution.
The 3.2 Agriculture & Home Pollution Worksheet provides an opportunity for students to actively engage with real-world data, fostering a deeper understanding of the complexities and impacts of agriculture and home practices on pollution. By honing their data analysis and interpretation skills, students can become more informed and conscientious citizens who can make informed decisions and contribute to addressing environmental challenges.
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