Students learn about water poverty and how water engineers can develop appropriate solutions to a problem that is plaguing nearly a sixth of the world's population. Students follow the engineering design process to design a gravity-fed water system. They choose between different system parameters such as pipe sizes, elevation differentials between entry and exit pipes, pipe lengths and tube locations to find a design that provides the maximum flow and minimum water turbidity (cloudiness) at the point of use. In this activity, students play the role of water engineers by designing and building model gravity-fed water systems, learning the key elements necessary for viable projects that help improve the lives people in developing communities.

Students are introduced to innovative stormwater management strategies that are being used to restore the hydrology and water quality of urbanized areas to pre-development conditions. Collectively called green infrastructure (GI) and low-impact development (LID) technologies, they include green roofs and vegetative walls, bioretention or rain gardens, bioswales, planter boxes, permeable pavement, urban tree canopy, rainwater harvesting, downspout disconnection, green streets and alleys, and green parking. These approaches differ from the traditional centralized stormwater collection system with the idea of handling stormwater at its sources, resulting in many environmental, economic and societal benefits. A PowerPoint® presentation provides photographic examples, and a companion file gives students the opportunity to sketch in their ideas for using the technologies to make improvements to 10 real-world design scenarios.

Students are presented with a guide to rain garden construction in an activity that culminates the unit and pulls together what they have learned and prepared in materials during the three previous associated activities. They learn about the four vertical zones that make up a typical rain garden with the purpose to cultivate natural infiltration of stormwater. Student groups create personal rain gardens planted with native species that can be installed on the school campus, within the surrounding community, or at students' homes to provide a green infrastructure and low-impact development technology solution for areas with poor drainage that often flood during storm events.

This lesson plan helps students understand the factors that affect water quality and the conditions that allow for different animals and plants to survive. Students will look at the effects of water quality on various water-related activities and describe water as an environmental, economic and social resource. The students will also learn how engineers use water quality information to make decisions about stream modifications.

Students explore materials engineering by modifying the material properties of water. Specifically, they use salt to lower the freezing point of water and test it by making ice cream. Using either a simple thermometer or a mechatronic temperature sensor, students learn about the lower temperature limit at which liquid water can exist such that even if placed in contact with a material much colder than 0 degrees Celsius, liquid water does not get colder than 0 °C. This provides students with an example of how materials can be modified (engineered) to change their equilibrium properties. They observe that when mixed with salt, liquid water's lower temperature limit can be dropped. Using salt-ice mixtures to cool the ice cream mixes to temperatures lower than 0 °C works better than ice alone.

Students learn about porosity and permeability and relate these concepts to groundwater flow. They use simple materials to conduct a porosity experiment and use the data to understand how environmental engineers decide on the placement and treatment of a drinking water well.

Students keep track of their own water usage for one week, gaining an understanding of how much water is used for various everyday activities. They relate their own water usages to the average residents of imaginary Thirsty County, and calculate the necessary water capacity of a dam that would provide residential water to the community.

Students learn about the human water cycle, or how humans impact the water cycle by settling down in civilizations. Specifically, they learn how people obtain, use and dispose of water. Students also learn about shortages of treated, clean and safe water and learn about ways that engineers address this issue through water conservation and graywater recycling.

Students are presented with examples of the types of problems that environmental engineers solve, specifically focusing on water quality issues. Topics include the importance of clean water, the scarcity of fresh water, tap water contamination sources, and ways environmental engineers treat contaminated water.

Students observe how water acts differently when placed on hydrophilic and hydrophobic surfaces. They determine which coatings are best to cause surfaces to shed water quickly or reduce the "fogging" caused by condensation.

Through multi-trial experiments, students are able to see and measure something that is otherwise invisible to them seeing plants breathe. Student groups are given two small plants of native species and materials to enclose them after watering with colored water. After being enclosed for 5, 10 and 15 minutes, teams collect and measure the condensed water from the plants' "breathing," and then calculate the rates at which the plants breathe. A plant's breath is known as transpiration, which is the flow of water from the ground where it is taken up by roots (plant uptake) and then lost through the leaves. Students plot volume/time data for three different native plant species, determine and compare their transpiration rates to see which had the highest reaction rate and consider how a plant's unique characteristics (leaf surface area, transpiration rate) might figure into engineers' designs for neighborhood stormwater management plans.

Students are introduced to the structure, function and purpose of locks and dams, which involves an introduction to Pascal's law, water pressure and gravity.

Students explore how different materials (sand, gravel, lava rock) with different water contents on different slopes result in landslides of different severity. They measure the severity by how far the landslide debris extends into model houses placed in the flood plain. This activity is a small-scale model of a debris chute currently being used by engineers and scientists to study landslide characteristics. Much of this activity setup is the same as for the Survive That Tsunami activity in Lesson 5 of the Natural Disasters unit.

In a class demonstration, students observe a simple water cycle model to better understand its role in pollutant transport. This activity shows one way in which pollution is affected by the water cycle; it simulates a point source of pollution in a lake and the resulting environmental consequences.

Students apply their understanding of the natural water cycle and the urban "stormwater" water cycle, as well as the processes involved in both cycles to hypothesize how the flow of water is affected by altering precipitation. Student groups consider different precipitation scenarios based on both intensity and duration. Once hypotheses and specific experimental steps are developed, students use both a natural water cycle model and an urban water cycle model to test their hypotheses. To conclude, students explain their results, tapping their knowledge of both cycles and the importance of using models to predict water flow in civil and environmental engineering designs. The natural water cycle model is made in advance by the teacher, using simple supplies; a minor adjustment to the model easily turns it into the urban water cycle model.

Through an overview of the components of the hydrologic cycle and the important roles they play in the design of engineered systems, students' awareness of the world's limited fresh water resources is heightened. The hydrologic cycle affects everyone and is the single most critical component to life on Earth. Students examine in detail the water cycle components and phase transitions, and then learn how water moves through the human-made urban environment. This urban "stormwater" water cycle is influenced by the pervasive existence of impervious surfaces that limit the amount of infiltration, resulting in high levels of stormwater runoff, limited groundwater replenishment and reduced groundwater flow. Students show their understanding of the process by writing a description of the path of a water droplet through the urban water cycle, from the droplet's point of view. The lesson lays the groundwork for rest of the unit, so students can begin to think about what they might do to modify the urban "stormwater" water cycle so that it functions more like the natural water cycle. A PowerPoint® presentation and handout are provided.

Students learn about the techniques engineers have developed for changing ocean water into drinking water, including thermal and membrane desalination. They begin by reviewing the components of the natural water cycle. They see how filters, evaporation and/or condensation can be components of engineering desalination processes. They learn how processes can be viewed as systems, with unique objects, inputs, components and outputs, and sketch their own system diagrams to describe their own desalination plant designs.

For students that have already been introduced to the water cycle this lesson is intended as a logical follow-up. Students will learn about human impacts on the water cycle that create a pathway for pollutants beginning with urban development and joining the natural water cycle as surface runoff. The extent of surface runoff in an area depends on the permeability of the materials in the ground. Permeability is the degree to which water or other liquids are able to flow through a material. Different substances such as soil, gravel, sand, and asphalt have varying levels of permeability. In this lesson, along with the associated activities, students will learn about permeability and compare the permeability of several different materials for the purpose of engineering landscape drainage systems.

Students investigate how different riparian ground covers, such as grass or pavement, affect river flooding. They learn about permeable and impermeable materials through the measurement how much water is absorbed by several different household materials in a model river. Students use what they learn to make recommendations for engineers developing permeable pavement. Also, they consider several different limitations for design in the context of a small community.

From drinking fountains at playgrounds, water systems in homes, and working bathrooms at schools to hydraulic bridges and levee systems, fluid mechanics are an essential part of daily life. Fluid mechanics, the study of how forces are applied to fluids, is outlined in this unit as a sequence of two lessons and three corresponding activities. The first lesson provides a basic introduction to Pascal's law, Archimedes' principle and Bernoulli's principle and presents fundamental definitions, equations and problems to solve with students, as well as engineering applications. The second lesson provides a basic introduction to above-ground storage tanks, their pervasive use in the Houston Ship Channel, and different types of storage tank failure in major storms and hurricanes. The unit concludes with students applying what they have learned to determine the stability of individual above-ground storage tanks given specific storm conditions so they can analyze their stability in changing storm conditions, followed by a project to design their own storage tanks to address the issues of uplift, displacement and buckling in storm conditions.