Unit 2: Measuring and Modeling Ecosystem Services
In this unit, students will model stormwater runoff for a landscape that has different land covers, to reflect the changes in the hydrologic cycle as land use changes. In doing this, they will (a) recognize the ecosystem services provided by natural or permeable land covers relative to stormwater runoff, (b) see how those services are impacted by land-use changes, and (c) consider what potential solutions are available to mitigate the impact of such changes.
Students will be able to infer and estimate the ecosystem services of natural or permeable land cover based on modeling the impact of development on the hydrologic cycle, specifically stormwater runoff.
Objectives to accomplish learning goal 2:
- Students will model the impact of development on stormwater runoff.
- Students will assess methods to mitigate the impact of development on stormwater runoff using using low impact development (LID).
Context for Use
This activity may be used either alone or in combination with Unit 1 as an introduction to modeling the impact of land-use change on stormwater runoff. It would be appropriate for use in a range of introductory courses, including courses in sustainability, ecology, environmental science, Earth science and geology, land-use planning, anthropology, water resources, and landscape design.
Class Size: This unit can be adapted for a variety of class sizes.
Class Format: This unit is designed for individual lecture sessions, but it is suitable for use in a lab setting or as a homework assignment as well. Students can work together, in groups of 2–4, but each student should complete his/her own assignment.
Time Required: The activities are designed to be completed in 50-minute class periods.
Special Equipment: Student groups should have a computer running Windows that has access to the Internet. The U.S. Environmental Protection Agency's National Stormwater Calculator, which runs only on Windows, must be installed from the Internet. The link is provided in the References and Resources section below. Because the calculator downloads soils data from a national database, Internet access is required during the activities in this unit. Not every student needs a computer for this activity, but at least one computer must be available per group. From the instructors' experiences, having at least one computer per three students is ideal.
Skills or concepts that students should have already mastered before encountering the activity: Activities in this unit assume familiarity with basic concepts of ecosystem services and the hydrologic cycle.
Description and Teaching Materials
The unit is made up of three activities:
- Modeling the hydrologic impact of land-use change using the EPA's National Stormwater Calculator (Calculator);
- Mitigation of increases in stormwater runoff using low impact development (LID) controls; and
- Modeling land-use change and mitigation strategies for a local land-use change.
The unit is designed for students to work in groups using the EPA's National Stormwater Calculator (Calculator). Either student laptops or university/college computers can be used, but the Calculator must be installed. The link is provided in the References and Resources section below. Because the Calculator downloads soils data from a national database, Internet access is also required. Not every student needs a computer for this unit, but at least one computer must be available per group.
Teaching Notes and Tips
The activities can be used in different ways. Units 2.1 and 2.2 can be used alone to introduce the Calculator and the use of LID controls to reduce stormwater runoff. Unit 2.3 can be used as a template, modified to represent a local problem on or near the instructor's campus. If the instructor is continuing with Unit 3: Using an Ecosystem Services Approach for Civic Engagement, the study site used in Unit 2.3 can serve as the focus for analysis of stakeholders' perspective as the students work to develop presentations about the proposed land-use change.
Ecosystem services and rainfall-runoff data in the context of the hydrologic cycle and water balance equation from Unit 1 is the foundation upon which students understand the need to consider impacts of development on stormwater generation and its management. Stormwater is currently managed in the campus environment; some students will be cognizant of that, and others will not. In this unit, students not only model changes in stormwater runoff that occur with development, but they also have to consider ways of mitigating or reducing it—in effect, managing it. Incorporating pre- and post-Unit 2 wrappers with the following three questions will allow the instructor to assess both prior knowledge and student learning:
- Is stormwater runoff generated by your campus? Yes or no, explain how you know this.
- What does the campus do to manage stormwater? Be as specific as possible.
- What could the campus do to manage their stormwater to take advantage of ecosystem services? Be as specific as possible.
One of these questions is part of a think-pair-share exercise in Unit 2.2. Answers to that question could also be recorded in writing for the assessment of student learning.
The pre- and post-assessment wrappers are included as Pre-Unit 2 Assessment Wrapper (Microsoft Word 2007 (.docx) 14kB Sep4 16) and Post-Unit 2 Assessment Wrapper (Microsoft Word 2007 (.docx) 14kB Sep4 16), respectively.
References and Resources
National Stormwater Calculator User's Guide Version 1.1
Description and download page for National Stormwater Calculator