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5 Ways to Introduce Students to Human Impact on the Water Cycle

Nabiha Khalid
Teaching with Labster
October 18, 2022

Introduction of Human Impacts on the Water Cycle

The presence of freshwater on the surface of the land is an essential component of the water cycle for the continued existence of humans. Rivers, lakes, reservoirs, creeks, and streams are all locations on the landscape that are capable of storing fresh water. Most of the water that people consume daily originates from these many sources of water found on the ground's surface. Freshwater makes up less than 2% of the total water on the planet; the rest of the water is found in the seas. Unfortunately, a significant portion of the freshwater supply is "frozen up" in glaciers and ice caps, making it inaccessible for human consumption. Saltwater comprises about 97% of the volume of water that is found in the world's oceans. 

Although they are extremely reliant on other aspects of the water cycle, most people consider the water bodies that are found on the surface of the Earth to be renewable resources. This is despite the fact that they are a component of the water cycle. The amount of water found in lakes and rivers is constantly shifting due to the influx and outflow of water. Precipitation, surface runoff, subsurface seepage, and inflows from tributaries are the sources of water that will enter these bodies of water. Evaporation, the passage of water into the subsurface, and water extracted by people are all examples of outflows that can occur in lakes and rivers. The complete water cycle is explained in the diagram below from Labster.

water cycle diagram

Oceanic storage is all saltwater seas. Freshwater is inland. Most of the world's freshwater is stored in glaciers and permafrost. Groundwater is the second-largest freshwater source. Only 1% of Earth's water is usable. Lakes, rivers, the ocean surface, and atmospheric water vapors are subject to fast water circulation. The deep ocean, groundwater, and cryosphere reserves can hold water for thousands of years or longer. Human actions affect the distribution, volume, and quality of water. Human impacts that affect ground, as well as surface water, are diverse. 

This isn't a full list of human consequences but focuses on widespread ones. Humans' influence on the water resources of almost all landscapes has been shown by significant human constructions and features that are superimposed on the notional environment. Human activities affect water quantity and quality over a vast range of time and space. 

Agriculture changes global landscapes. Tillage influences the infiltration and runoff properties of the land surface, affecting groundwater recharge, surface-water delivery, and evapotranspiration. Each of these processes affects ground-surface water interaction directly or indirectly. Agriculturalists are conscious of agriculture's harmful effects on water supplies and have developed solutions. 

Tillage procedures have been adjusted to increase soil water retention and reduce soil erosion into surface water. Cropland chemicals and fertilizers can contaminate water. Some pesticides are very minimally water soluble and may adhere to soil particles rather than remain in solution, reducing groundwater exposure.

Deforestation is the cutting down of trees on a massive scale. Deforestation in the Watershed has been found to have significantly reduced interception (76%) as well as evapotranspiration (12%). Total runoff, interflow, surface runoff, and base flow all increased in the same period. According to forestry and hydrology studies, forest loss results in less precipitation penetrating the soil and more runoff into streams and rivers. Because trees form more solid macropores, areas with trees often have higher penetration rates than grassland or pasture without trees.

 When a city's population grows, individuals may move to surrounding towns. This is called urbanization. As urbanization grows, urban land use changes, increasing impermeable surfaces and limiting infiltration during storms, which impacts urban hydrologic processes. Less water infiltrates, and more flows off as imperviousness increases. Over half of all rain in urban areas generates surface runoff, and deep penetration is a fraction of what it was originally. Flooding is worsened by increasing surface drainage. Due to rainwater interception, urban trees can minimize the quantity of precipitation that reaches the ground and regulate stormwater volumes and expenses. The study examined urban rainwater absorption.

Why is the Human Impact on the Water Cycle tricky for students?

1. A comprehensive topic

This topic covers many cycles, such as water, carbon, nutrient, nitrogen, etc. Further, it includes the concept of evaporation, precipitation, groundwater runoff, interception, and infiltration. Then after that, there is a concept of distribution and usage of water. With the progress into the 21st century, human impacts are evolving too. It is much more than deforestation and urbanization. Gaining all of this knowledge leads to confusion among students too. 

2. Fact telling

The teaching style consisting of stating facts might be boring for students. They are gaining the mental picture from the textbook diagram; therefore, their ideas and creativity about water movement around the Earth can be minimized. Students frequently believe that this topic is nothing more than the accumulation of various pieces of information. Consequently, they are only aware of a singular perspective on a topic or problem rather than the comprehensive picture.

3. Misconceptions

Students frequently have misconceptions, such as the notion that the water cycle consists of nothing more than the water's evaporation from the Earth into the atmosphere and its subsequent condensation back onto the Earth. Similarly, about the human impact, they only think about water waste and how Earth is running out of pure water. The tendency of students to misunderstand the human contribution to the water cycle may be one factor that contributes to their difficulty in appreciating the relative importance of the water cycle's many reservoirs.

Five ways to make Human Impact on the Water Cycle a fun topic for students

1. Activities-based approach

Instruct students on the assignment of drawing in notebooks the essential parts of the water cycle. Students who have trouble remembering the terms should probably have the necessary terminology written on the board where they can see it. Construct a model to illustrate the path that pollution, deforestation, and urbanization takes through a watershed's groundwater and surface water. Create an information sheet for the general public that identifies the elements that contribute to water pollution as well as the strategies that can be used to lessen pollution in the watersheds.

2. Building the basics

Clear the confusion between the terminologies as discussed above. Students need to have a fundamental understanding of the Earth's water cycle and the principles of runoff and infiltration to a groundwater level. It is beneficial to have prior information on both the source of our drinking water and the topic of global warming. The students' responses may differ, but they ultimately lead them to the realization that a cycle denotes a process that repeatedly occurs of these items. 

3. Scientific investigation and reasoning.

Students should be allowed to compute the quantity of used water that is created by households of varying sizes in one day. Additionally, they can use a model of home plumbing to determine the amount of pollution produced. How much deforestation they have seen and can cause an impact. They should also be given the opportunity to devise methods for either cleaning an existing water source or finding a new water source, depending on the hypothetical family situation presented to them. They put on their engineer hats and draw and explain how they might be able to help a village that is in the midst of a water crisis by providing water to the community. They will do their own investigation.

4. Help them realize the value of human impact on the water cycle

Tell students how our actions can cause massive responses for generations in the future and ourselves. Educating students about their responsibilities does not mean simply informing them about their responsibilities. It is the act of explaining topics and imparting knowledge to people so that they can make their own judgments based on that understanding. Encourage children to recognize the significance of water-related issues and get them involved in discussions on themes such as water conservation, the usage of clean water, and the protection of ecosystems.

human impacts on water cycle GIF

GIF from Labster's Human Impact on the Water Cycle simulation.

5. Use virtual lab simulations

The conventional lessons taught in schools about humans' impact on the water cycle are not always seen as particularly interesting. As the world continues to evolve, there will be a greater need for ecologists who can appreciate the environmental challenges and actively fight to protect the water supply for all kinds of life. Because there are not enough resources available to make it simpler for teachers to educate their students about the impact that humans have on the water cycle, we have built interactive simulations in order to come to your aid. Check out Labster’s Human Impact on the Water Cycle simulation, which will make it much simpler for you to deliver your presentations.

Human impact on water cycle virtual lab

You now have the ability to make more insightful arguments because students can access picture and video alternatives. You will focus on deforestation and urban development, particularly how these factors influence surface runoff, infiltration, and interception. You will have the option to make adjustments to a variety of parameters and put your model to the test to see if you can keep your community from becoming flooded. Looking at the water cycle from this angle will give students a fresh perspective and clarity about the basics. 

The simulation above describes how water moves around the Earth in a continuous cycle and how human activities cause impact its quality and quantity. 

References

https://www.pnas.org/doi/abs/10.1073/pnas.1222475110

https://acsess.onlinelibrary.wiley.com/doi/abs/10.2134/agronmonogr55.c14

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