Water-Supply Challenge

By Aaron Swink

We all learned in school that two-thirds of the Earth’s surface is covered in water, but only 3 percent of that is fresh water. And of that, only a fraction is available for human use; that is comparable to taking a single drop from a gallon jug. In Central Texas, rapid population growth coupled with inconsistent rainfall, exacerbated by climate change, leads to water conservation being discussed with ever-increasing urgency. It’s no surprise that we find water resources being stretched more with each passing decade. Training the next generation of water-wise Texans is the key to the future. The Edwards Aquifer Research and Data Center at Texas State University in San Marcos was founded in the 1970s to study and promote conservation of the region’s limited water resources. Central to that mission is the Aquatic Science Adventure Camp, which celebrated 30 years of operation this year and is one of the longest-running summer science camps in Texas.

The goal is to give children a genuinely fun, engaging, and educational experience that opens their eyes to the wonders of nature and inspires their innate desire to understand it. We aim to take science learning out of the classroom and allow campers to discover much the fun of being a scientist! Through an array of outdoor recreational activities and scientific investigations related to water and the environment, we give campers a taste of what science is really like. Our motto is “Real Science, Real Fun!”

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Water-Supply Challenge
One of the core activities is designed to get campers thinking about the logistical, physical, and environmental challenges of supplying drinking water. Often, campers know their drinking water comes from a lake, river, or aquifer, but they don’t know much about how that water gets to their house. This activity is also a great hands-on way to teach the physics of water, such as hydraulic pressure and the energy required to move water. It’s fairly simple and doesn’t require specialized equipment or space, and we also find it to be a popular and effective teaching activity with campers.

Goal Of The Activity
Campers are divided into two groups that represent competing water-supply utility companies. The goal is to move water from its source to their “customers” in the fastest way and with the least waste.

Equipment Needed
This activity can be anything from a simple demonstration to a complex project in which students work to design and plan their route ahead of time and then implement it. We generally strike a middle ground where the total time for the activity is under an hour. For this level, the supply cost should be less than $100.

  • A body of water. This can be a natural feature, such as a pond or just a kiddie pool filled with water.
  • ¾-inch-diameter PVC pipes cut into various lengths. We issue each team about 60 feet of pipe cut into 1- to 5-foot sections.
  • An assortment of connectors and valves. A simple system can use elbows and straight connectors, while a more complex system can incorporate junctions and cutoff valves.
  • Hand-operated water pumps. We use basic liquid-transfer pumps that are readily available online or at hardware stores. Any type of hand-operated transfer or bilge pump will do, although some designs may be more challenging for younger students to use.
  • Two 5-gallon buckets to be the “water towers.” These buckets should have holes cut into the sides with attachments for the piping to be connected, one near the top of the bucket for the inlet and one at the bottom for the outlet. Take a ruler and mark off the inches on the inside and outside of the bucket.
  • Plastic tubing and adapters to allow pumps to connect with PVC pipes. This may take some experimentation to design a system that will work well with your set-up and goals for the activity.
  • A step ladder, table, or objects than can be stacked to create surfaces of different heights.
  • Plastic cups.
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Setup

1.       Map out the area you want to use for the activity. You’ll need surfaces of different heights in order to place the “water towers” (5-gallon buckets) and “customers” (cups). You can set up tables, chairs, or a step ladder to achieve this, or you can use a natural rise in the land or a retaining wall. For our set-up, we use either a folding table or a small hill, depending on the age group. The hill may be too tall for younger campers.

2.       Place pairs of cups in different locations around the area. These will be the customers’ houses. In each pair, one cup will be the customer for each team at each location. You’ll want some cups at ground level and others at different heights by putting the cups on chairs, step ladders, plastic tubs, etc.; more locations and elevations will increase the time and difficulty for the activity.

3.       Place all the equipment in two piles, one for each team. We spray-painted one team’s pipes orange in order to be able to tell them apart. Divide the participants into two groups. The max group size will depend on your set up, but groups of 8 to 12 are about right.

4.       Explain to participants that the goal is to take water from the source to each customer’s house. This is a good opportunity to talk to participants about how water flows under gravity and why water towers are used as part of a municipal water supply. Tell them the first decision they will have to make is where to put the water tower. It will need to be higher than the highest customer. Explain that the higher the tower is placed, the more water pressure can be generated and thus their customer cups can be filled faster, but it will also take more energy to pump the water into the tower. Once a group places its tower, it cannot be moved. Explain the second goal of being the most efficient. Whichever group can supply its customers and have the most water left over in the water tower wins the efficiency award.

Running The Activity
Once you say “start,” students have to work together to decide where to put the water tower. Once they do, encourage them to divide the work load into pipe layers, pumpers, and leak fixers as they work to pump water into the tower and run their supply lines. It’s best if you have some type of cut-off valve at the water tower so it can be filled all the way up before they start supplying water to the customers. Teamwork and creativity are essential as they troubleshoot various obstacles. Leaking pipes, inefficient routing, the physical effort of using the pumps, and communication with other members of the team are all things the camp staff can help students think through and problem solve. For a more difficult challenge, you can say that once pipe is laid it can’t be moved, or you can allow teams to disassemble pipelines and move the pieces once that customer has been supplied. Once both teams have supplied water to all their customers, you may announce the winners based on who fully supplied their customers first, and who had the most water left in their tower. Often, these are two different teams!

Learning Outcomes
At the end of this activity, students will have seen first-hand how difficult it can be to provide a drinking-water supply. They will have experienced the power of gravity and the work it takes to overcome it. They will also have been challenged to design and maintain their system and overcome the frustration of pipes that come apart and leak. After the activity, we have a debrief time when we review some of these lessons more explicitly and ask students to share their biggest challenges and how they overcame them. You can also discuss environmental impacts by asking how much water was drained from the water source and how sustainable that is. This creativity and problem solving are what make this activity both fun and highly educational for campers.

Aaron Swink is the Education Director at the Edwards Aquifer Research and Data Center at Texas State University. He can be reached at 512-245-3541 or aps36@txstate.edu. See more about the Aquatic Science Adventure Camp at www.eardc.txstate.edu/camp.html.