Capture that Rain! When it rains, it pours, creating storm water runoff and water quality problems in our region. Students will assist Ontario Municipal Utilities Company s Water Resources Coordinator in developing rainwater harvesting designs to reduce runoff. Working as environmental engineers, they will design and test a system to capture rain to irrigate a garden. In small teams, students will be given a set of materials, guidelines, and a time limit to construct a model. Each group will test their design to see what best maximizes rain capture. They will then explore examples of rain harvesting designs on our campus.
Pre-Event Activities Capture that Rain! Pre-Field Trip Suggestions 1. Review the water cycle. Ask students to hypothesize how the surface of the ground (i.e. pavement, grass, gravel, sand) affects what happens when rain hits the ground. For example, is runoff or infiltration more likely to occur on pavement? And what about turf? Use attached surface cover sheet as prompt for this discussion (see Pre Lesson Surface Cover Sheet). Introduce the terms impervious and pervious, and discuss with students that pavement is impervious and areas covered with plants are pervious. 2. Map out schoolyard, identifying impervious and pervious areas. Students can either go outside and make observations in schoolyard or use a satellite image of their school. Screenshots from Google Maps with Google Earth terrain turned on works great. On their maps, students can outline areas where they think water will soak into the ground (i.e. pervious areas) with a green marker. They can outline in black areas where they hypothesize water will run off (i.e. impervious areas) with a black marker. After discussing the water quality impacts of runoff from paved surfaces and the opportunities to capture rainwater to help conserve water by using it water plants or to recharge our groundwater basins, ask students to use red markers to brainstorm areas where they think water could best be captured in their schoolyards (roofs, low areas, sediment basins by parking lots, etc).
Activity Instructions Capture that Rain! This engineering based activity poses a design problem to students, giving them the opportunity to work in groups to formulate a solution and test their team design. Vocabulary: Impervious: Not allowing fluid to pass through Pervious: Allowing water to pass through; permeable Permeable: (of a material) Allowing liquids or gases to pass through it Impermeable: Not allowing fluid to pass through Infiltration: The process by which water on the ground surface enters the soil. Groundwater: The water found underground in the cracks and spaces in soil, sand, and rock Rain Garden: is a garden designed and used to capture and store water. Runoff: Precipitation that neither evaporates, transpires nor penetrates the surface to become groundwater, instead, the precipitation ends up traveling to the oceans. Design Problem: Your city gets its water primarily from the Chino Groundwater Basin. Currently, your city is facing two issues. One, there is not enough water infiltrating (draining) into the groundwater basin to provide the water needed for your city s residents. Secondly, because there is so much pavement in your city, when it rains, the water runs off into storm water drains, and flows out to the ocean instead of infiltrating into the groundwater basin. The runoff, known as storm water, carries many pollutants from the streets, causing poor water quality. Design Challenge: As your city s environmental engineers, your challenge is to design a rainwater capture system for your school. You will design pervious areas in the schoolyard to capture rainwater and allow it to infiltrate into the groundwater basin before running off into the streets. This will allow your city to have a more reliable and cleaner groundwater drinking source.
PROJECT INFORMATION AND PARAMETERS Capture that Rain! Activity Continued... 1. You have a model of the schoolyard. Currently, the entire campus is paved with an impervious surface. 2. You can use any combination of the five materials provided (clay, sponge, microfiber, paper towels, and straws) and tape to capture rainwater so that it does not runoff and carry pollutants into the ocean. These pervious materials represent plants, soils, mulch, and other natural materials that allow water to infiltrate into the ground. 3. DO NOT begin construction or add materials to your landscape until you have your design approved by an instructor or volunteer. DESIGN PHASE 1. Using the markers, create a design plan for where you want to place each material. Outline on the landscape where each material will be used to capture rainwater. Use the post it notes to label what material will be used in each area. 2. On the Design Cost Sheet, calculate the total cost of your system design. 3. Once your team is confident in your design, have an instructor or volunteer approve the design and total calculated cost. CONSTRUCTION PHASE 1. Construct your design using the materials. Use the tape to attach each material to the landscape. TEST PHASE 1. Using the spray bottle, apply 100 ml of water uniformly across the landscape. 2. Once all of the water is applied, use the eyedroppers to collect any water that was not captured by your materials and measure that water in the provided beaker. This is your total storm water runoff. Record the total storm water volume (ml) here. TOTAL STORM WATER RUNOFF: ml 3. How did your design perform? Discuss with your group what was successful about your design. What would you change?
Post-Event Activities Capture that Rain! Post-Field Trip Suggestions 1. Students will take what they learned, and map out rain garden designs in their schoolyard map. Their goal will be to identify where a rain garden would best be located, and how they would design their rain garden. 2. Students will determine what design considerations are the most important (placement, soil material, plant material, and aesthetics). We will provide a limited plant and material resource guide as a reference (last page of this handbook section). Students select what soils and plants would create the optimal rain garden to meet their design considerations. 3. The final project could be a written proposal to their school district proposing and defending their rain garden design.
Design Cost Sheet Material Cost per Unit Total Number of Units Sponge $500 Microfiber $400 Paper Towel $100 Straws $300 Clay $100 Total Design Cost $ Total Cost for Material
Native Plant Landscapes Turf Permeable Pavers Pavement Will rain infiltrate (drain) or runoff of each of these surface covers? Pre Lesson Surface Cover Sheet
Post Lesson Rain Garden Materials Resource Guide Soil Material Characteristics Clay Plant Material Characteristics Yarrow Small, fine particles. Does not allow water to drain quickly. Loam Easy to maintain Need full sun Need little to moderate water Can withstand both dry periods and rainy periods California Poppies Drains more quickly than clay but more slowly than sand. Holds more plant food or nutrients to allow for plant growth. Sand Turf grass Coarse particles. Water drains quickly. Does not retain nutrients which provide the necessary food for plant growth. Need to add compost or fertilizer to help hold water at the surface of the soil and improve its nutrition for plants. Gravel Large particles. Water drains very quickly. It is more difficult for plants to root in gravel and find nutrients and water. Pink Flowering Current Need well drained soil Can withstand full sun Needs little water Blooms in spring and summer Providing additional water in the summer time will make their flowers last longer in the fall High water user. Typically uses twice as much water as native plants. Does best in rocky, well drained soil in sunny locations. Provided shade to plants below. Blooms in the spring. Moderate water use. Moderately drought tolerant