Green Stormwater Planning

plant_grouping_01Goal: Develop a plan for how to move forward on catching rain where it falls on the school campus

Objectives: Students will . . .

  • Discuss options for green stormwater systems on campus and come to consensus about how to move forward in planning
  • Use criteria to evaluate options for green infrastructure projects
  • Compare locations on a map to locations in real life
  • Make sketches on a map to represent proposed rain catchment systems

Materials: campus maps used in Calculating Stormwater Runoff, clipboards, pencils

Advance Preparation: get a map of buried utilities from school facilities department (this would be a great time to talk to them about the project!)

Timing Estimate
10 min Intro & group brainstorm
10 min Discussion on how to move forward with planning
25 min site visiting
5 min Back to class and pack up

Instructional Plan

You’ve calculated the amount of rain that runs off your school campus in a 1” rain and in a year. Now that you know where the water is coming from and how much there is, you can start to figure out how to keep some of it where it falls (instead of running into the storm sewer or combined sewer).

What can we do about stormwater runoff? Brainstorm

Ask students to brainstorm a list of all the strategies they saw at the Green Learning Station to keep stormwater where it falls. A complete list includes:

  • Vegetated roofs (four types demonstrated)
  • Permeable pavers, pervious concrete, porous asphalt
  • Rain gardens and bioswales
  • Rain tanks of different sizes
  • Planting trees and large plants instead of lawn

Based on the specifics of your campus and how water moves on it, which strategies would make sense to explore at your school? Brainstorm as a group.

You can steer your students away from high cost infrastructure projects like green roofs or pervious paving OR let their imaginations run with it and have them draw out a plan and calculate the costs. Rain gardens, bioswales, tree planting and rain tanks are going to be the less expensive options and this curriculum will focus on those.

Depending on the students’ interests, have them come up with a basic plan for how to proceed. If everyone thinks rain gardens are the way to go, have the whole class work on the lessons related to that. If there are a number of different infrastructures students are interested in, divide the class into groups according to interests and have each come up with a plan.

Planning in the Field

You got a lay of the land while calculating stormwater runoff. Now it is time to develop a specific picture of what the class can do to decrease storm water runoff from the school.

Have students take the campus maps they worked on in Calculating Stormwater Runoff and head outside to scope out potential locations for bioswales, rain gardens, rain tanks or tree planting (based on class interests).

Smart rainwater management pays close attention to where water goes naturally, the slope of the land and the absorbency of surfaces. Are there any spots on your school campus that would make good locations for rain gardens or bioswales? Here are some factors to keep in mind, bring them up as students are looking for placement ideas:

  • Rain gardens and bioswales should be located at least 10 feet from any buildings to avoid foundation flooding.
  • Consult the buried utilities map to ensure you would not be disturbing underground pipes and wires.
  • How are the spaces used: is there heavy foot traffic or are certain areas hang-out spots?
  • How will the location influence views or existing landscaping plans?
  • Is the site easy to access for pedestrians and classes who would want to visit it?
  • How close are potential garden sites to large trees whose roots would be disturbed by excavation?

Rain Gardens are best located in areas where they can collect water from other places (like a roof or parking lot). Naturally low lying or bowl shaped areas can be perfect for rain gardens, as long as they have good drainage. You can also put a rain garden on a slight slope or in a flat area, it will just require more excavation and shaping of the garden. If you already have grass swales (ditches that carry stormwater) on your campus, you can easily plant larger plants in them, which will absorb more rain than turf grass.

Students should sketch ideas on their maps of where they would want to site rain catchment features (tanks, gardens, etc). They can work alone or in small groups to share their ideas.

In the last five minutes of your time outside, or in each location you visit, ask students to share their ideas with the rest of the class. By the end of class, try to bring the class to a consensus around a couple of potential projects. Or spend some time the next day making a master list of ideas and whittling them down to one to three projects. If you have multiple classes, you will need to decide if you want each class to tackle a unique project, or somehow collaborate on one endeavor.

Click here to download PDF file.