Prairie Eco Services
As densely populated urban areas continue to expand, human activity is removing much-needed greenspaces from our communities; in turn, we are also removing critical buffers that are needed to combat air and water pollution, leaving cities vulnerable to a variety of health issues and potential infrastructure damage. In August of 2017, the Greater Houston area experienced a catastrophic flooding event, with Hurricane Harvey being designated as the wettest tropical cyclone ever recorded in US history. With many areas receiving 40" or more of rain, the rising flood waters had nowhere to go in a city covered in concrete, a barrier to natural infiltration. This caused over $125 billion in damage, with flood waters inundating hundreds of thousands of homes and displacing more than 30,000 people. In 2018, Katy High School responded by restoring an acre of public campus property to native Texas Gulf Coast prairie. The prairie will ultimately serve as an outdoor classroom for students, a greenspace for community outreach, and also as a natural retention area for future flooding events. Urban greenspaces, like the KHS Tiger Prairie, are mini-ecosystems that can potentially mitigate billions of dollars in flood damages while conserving precious habitats for native species; these pocket prairies not only model of conservation best-practices, but they also provide multiple, quantifiable ecoservices to communities. The KHS Tiger prairie will serve as a model for this activity, allowing students the opportunity to calculate the quantifiable cost-savings of incorporating native landscapes in their communities. Students will analyze recent precipitation and infiltration data, make predictions on which locations in urban areas have the most potential for restoration, and reflect on the societal and economic barriers to current conservation efforts.
Strengths of Module
Students are constantly affronted with data-driven environmental and political issues, with these issues constantly changing due to the ever fluctuating landscape of climate change. This module aims to equip students with the decision making skills necessary to be powerful influences in their communities and in the fight to make sustainability a global effort. This module introduces students to real-world, relevant data from recent flooding events in the greater-Houston area, and forces students to weave together disparate forms of data, including large, publicly-available numerical datasets on temperature, precipitation, and infiltration rates, spatial data representations in both ArcGIS and Google Earth, and introductory modeling platforms such as "Model My Watershed." Students will exercise key decision making skills as they formulate their own analytical inferences while also considering a variety of socioeconomic and political issues that exist at the local, state, and national levels.
What does success look like
Students will be able to formulate a 'community action plan' by: 1.) assessing the risk of future natural hazards and flooding events in the Houston area, 2.) quantifying the potential damage of future flooding incidents, 3.) evaluating current mitigation techniques and providing alternative, eco-friendly solutions, and 4.) identifying barriers to the implementation of their plan, as well as possible ways to overcome those barriers. Students can present their findings in a variety of formats, such as written or oral reports, poster presentations, Claim-Evidence-Reasoning (CER) gallery walks, etc.
Context for Use
This module was written for secondary and post-secondary academic levels, and is applicable to a variety of Earth Science, Environmental Science, and Ecology units. The module explores topics relevant to soil properties, hydrology, meteorology, climate change, botany/biology, land use studies, and general data-analysis. The format of this module provides a variety of options for implementation, allowing instructors to tailor the rigor of assignments to the appropriate academic abilities of each learner or the time allotted for each unit. This activity is intended to be implemented in student groups or pairs, but could also be assigned as individual work.
Description and Teaching Materials
The suggested workflow for this activity (also documented in the instructor's guide below) is for instructors to first administer the pre-module student self-assessment. This formative tool allows instructors to measure students' current quantitative skill sets, and match strongly quantitative students with those needing extra peer support. This also allows teachers to gauge the overall "success" of skills acquired during the module, after the post-module assessment is administered. After the pre-assessment, teachers can give a brief background summary of the module, the history of the KHS Tiger prairie, and the relevance of the issue being explored. This is also a good time to assign any pre-module readings from the list of suggested references below. Teachers may then proceed to parts A and B, and potentially C and D, as time permits. This module requires that students have access to a computer lab, a class-set of laptops, or their own personal electronic device for data downloads, graphing, and analysis. All ancillary materials/handouts are provided in the links below.
Why this Matters:
This activity explores eco-services provided by local native greenspaces, using case-studies of land use in Harris County, TX, and its impact on local flooding. Students will analyze historical precipitation data, predict future flooding patterns based on past extreme weather events, and quantify potential mitigation techniques by incorporating greenspaces in urban areas. Numbers are a crucial part of monitoring progress of such projects, and are powerful indicators of overall success. This module gives students first-hand experience in analyzing real-world datasets, and quantifying the potential impact of greenspaces in flood-prone areas, like Houston and other major cities along the Gulf Coast. This serves as a critical skill-building opportunity for students as they move from passive consumers of information to active citizen scientists who can influence public policy in their own communities.
Quick outline/overview of the activities in this module
- Pre-module work: student pre-module self-assessment, engage video, PowerPoint in class, at-home guided reading
- Activity A: students will investigate and plot historical severe-weather data from the NOAA website (on student handout) and predict the likelihood and severity of future flooding events.
- Activity B: students will investigate land use patterns in the Texas Gulf Coast region and analyze the relationship between land-use and infiltration rates.
- Activity C: students will evaluate the eco-services provided by prairies; in particular, students will model the additional infiltration capacity of 1 acre of native Texas grasslands. Students will quantify the amount of displaced flood waters as well as the cost-savings provided by native greenspaces.
- Activity D: students will synthesize their interpretations from activities A-C into a community action plan; students should write their plans using collective impact strategies and incorporate data findings to support their statements.
Workflow of this module:
- Pre-assesesment: EDDIE pre-assessment.pdf (Acrobat (PDF) 289kB Feb10 20)
- Assign any pre-class readings
- Give students their handout when they arrive to class
- Instructor gives brief PowerPoint presentation with background material. Discussion of the readings can be integrated into this presentation or done before.
- Students can then work through the module activities.
- Presentation of student findings
- Post-assessment: EDDIE post-assessment.pdf (Acrobat (PDF) 290kB Feb10 20)
Potential pre-class readings:
- Living with Water, (see page 24-39), Office of the Mayor, City of Houston
- How Houston Could Reduce Storm Flooding, Kat Friedrich, Conservation Finance Network, February 21, 2018.
- Court Holds Army Corps Responsible for Hurricane Harvey Flood Damage, Thomas Frank, Scientific American E&E News, December 19, 2019.
Students will investigate precipitation (rain) patterns for the Gulf Coast area. By reviewing historical weather data, students will be able to identify relationships between hurricane frequency and intensity for the Gulf Coast region. Essential questions: what is the relationship between temperature and precipitation? What is the relationship between global warming and the frequency/severity of cyclonic events? Students will work in pairs to plot a subset of historical precipitation from the NOAA website: https://www.weather.gov/hgx/climate_hou_normals_summary
As students begin reviewing the data, they should ask themselves and engage in a think-pair-share around the following questions:
- What kind of data am I looking at?
- Where/how was this data collected?
- Which numbers do I actually need to use, if I am curious about historical precipitation patterns? Monthly precipitation? Annual precipitation?
- What numbers DON'T I need?
- How could I represent these data visually, in a graph?
Once students have completed the above think-pair-share, they should enter the data into Excel or Google sheets. Students should create a scatter plot with their data, and if possible, create a trend line.
Using their scatterplots, students should be able to answer the following essential questions:
- What patterns do I see in the data? What inferences can I make about future rainfall in Houston, TX? Is there a clear trend in precipitation patterns? If so, what is that trend?
- What errors might there be in the data?
Extensional option: students will create 'error bars' on their data, showing the deviation from the historical precipitation yearly average. Students could also just add a baseline representing average rainfall.
Students will evaluate land use practices in Harris County, TX, and analyze the relationship between land use and infiltration. Students, working in pairs, should go to: http://www.modelmywatershed.com
Students should take 5-10 minutes to 'play around' with the various options. (For instructions on how to create a project or navigate, go https://wikiwatershed.org/help/, or for a quick simulation on land use and infiltration rates, visit :https://runoff.modelmywatershed.org/).
Students will complete a short land-use study, looking at land use and watershed maps in the greater Houston area (instructions included on student handout sheet).
Students should consider the following essential questions:
- how should I delineate my model's boundary type? Which boundary type best reflects the precipitation data plotted in Activity A?
- what features are being shown on this map?
Once students delineate their watershed (for this exercise, county lines work best), they can analyze the various watershed properties. Students should be able to answer the following questions:
- What is the primary land-use for Harris County? How many acres? What percentage? Where is this type of land use located?
- What types of 'open water' exist in this area? How might that impact local drainage patterns?
- What types of soil are present in this area? What are some potential barriers to infiltration?
Students can now MODEL how extreme precipitation events impact infiltration. What would an extreme weather event (like Hurricane Harvey!) look like? Students should model a '24-hr hypothetical storm event.' To select the amount of storm precipitation, students should estimate a reasonable number by review 10-year storm events from the websites below:
Extensional option: students will 'deep dive' into the data, reading meteorological reports to answer the following questions: which event was costliest (in TODAY's dollars?), which event induced the highest flood waters?, which event caused the most human fatalities?
When students select the amount of rainfall for their 24-hour period (don't forget to convert inches to cm!), they can scroll the precipitation toolbar in ModelMyWatershed back and forth to see how infiltration rates change.
Students should be able to answer the following essential questions:
- What is the total volume of water as runoff? How much water was absorbed (infiltration)? How much released as evapotranspiration?
- What are some land-use factors that contributed to the extreme flooding caused by Hurricane Harvey?
Students will evaluate the eco-services provided by native greenspaces, like the KHS Tiger prairies. In particular, students will model the additional infiltration capacity of 1 acre of native Texas grasslands to the Houston metro area. Students will quantify the amount of displaced flood waters as well as the cost-savings provided by native greenspaces.
Background reading: students should visit the website http://www.tigerprairie.org and answer the following questions:
- How many acres is the Tiger Prairie? What types of plant species are in this prairie? List THREE things you learned (and previously didn't know!) about prairie plants!
- How do prairie plants impact infiltration rates? Prairie plant root systems vs. turf grass.
(Related resource: https://pubs.usgs.gov/sir/2010/5077/pdf/sir20105077.pdf)
Students should return to their watershed model, and find Old Market Square, which is in downtown Houston, at the intersection of Milam Street and Congress Street (or Travis Street and Congress Street). Students should convert this park into native grasslands, by going to the top toolbar called 'land cover', and toggling on the grasslands option. Students can then create a polygon over Old Market Square. This is approximately 1 acre (4,700 m2) of land. (conversions: 1 km2 = 247 acres or 4047 m2 = 1 acre)
Students will rerun their model and answer:
- What was the NET change in the volume of water (in m3) that was diverted from runoff into infiltration and evapotranspiration pathways? (approximately 253 m3)
- What is that volume in gallons?
- Study the image in the student handout: how many gallons of water fell on Houston during Hurricane Harvey? (24,000,000,000,000 gallons)
- How many 1-acre pocket prairies would you need to divert 1,000,000,000 gallons of rain? (1 billion/66,792 = 14,971 acres)
Now go to Arc GIS to view inundation maps of standing floodwaters from Hurricane Harvey:
(Students should click on "I" to briefly read the background information describing how data was gathered, processed, and published in this map.) Next, students will click on the base map gallery: toggle on/off various base maps until you find one that you feel is best for showing flood features. (students may also go to https://maps.woolpert.com/harvey/#c:-10650413,3468571;z:14;t:e)
Students should zoom into Houston until they can identify specific features; they will then slide the image left (before) and right (after) to view the changes from before Hurricane Harvey (September 1, 2017) and after (August 31, 2017)
- Essential questions: what parts of Harris County were most impacted (most inundated)? What flooding patterns do you see? Standing flood waters correspond to what natural features? And what man made features?
- Looking at the Arc GIS inundation map, students will identify five areas where you could easily install a pocket prairie/native greenspaces. (be specific! Lat long or cross streets!) Please will need to list the criteria they used to select their locations. (Parks? Hardscaped areas? Areas near major streams and bayous?)
After selecting their five locations, students will go back to ModelMyWatershed and draw polygons around each of their five locations, and set the land use type to 'grassland.'
- Essential questions: how many acres of prairie did you convert? Rerun your simulation. How many gallons of water did you divert? Students will complete a cost-benefit analysis to predict the the future savings of incorporating pocket prairies in urban communities.
Students will now look at ways to incorporate native greenspaces as part of "smart growth" in urban planning. Clearly, urban greenspaces have the potential to provide multiple ecoservices, and for the Houston area, that includes flood mitigation. Using the data students have just interpreted and the cost-savings they have calculated, they will create a persuasive proposal to Houston community leaders citing a location in the Greater Houston area they believe should be converted to greenspace (remembering which locations have the biggest impact when converted to native prairie!). Students will present their findings in CER (Claim, Evidence, Reasoning) format: they will create a poster that identifies the guiding question ("Where would be the ideal location for a proposed greenspace?"), their claim ("we propose installing a 1-acre pocket prairie at location x"), and will defend their claim with evidence and a solid justification.
- Instructor's PowerPoint (PowerPoint 2007 (.pptx) 43.7MB Sep29 21)
- Student Handout (Acrobat (PDF) 529kB Sep27 21)
- Dataset (Excel 2007 (.xlsx) 25kB Feb10 20)
Teaching Notes and Tips
This module is meant to be adaptive to student needs and instructor time constraints. While the activities are intended to be cumulative (they build off one another), each activity can be taught separately to address specific learning objectives.
Measures of Student Success
Students will show an increase in overall confidence of quantitative reasoning skills as demonstrated in pre-assessment and post-assessment scores. In addition, students will synthesize historical climate data (precipitation/temperature) with current land use practices (ArcGIS) into their own action-plans as presented in final products of Activity D.
References and Resources
- NOAA Billion-Dollar Weather and Climate Disasters: Time Series: https://www.ncdc.noaa.gov/billions/time-series/US
- Eco-Logical mapping application: https://datalab.h-gac.com/EcologicalGIS/?fbclid=IwAR0ALyupe33yJRUVQs-USoiBb7DJvOiHqo8SpOZUJk-DD8WUJ8XidA0Rq78
- Long Term Hydrologic Impact Analysis (L-THIA): https://engineering.purdue.edu/~lthia/
- How Houston Could Reduce Storm Flooding: https://www.conservationfinancenetwork.org/2018/02/21/how-houston-could-reduce-storm-flooding
- Regional Impacts of climate change
Four Case Studies in the United States: https://www.c2es.org/site/assets/uploads/2007/12/regional-impacts-climate-change-four-case-studies-united-states.pdf
- 2014 National Climate Assessment: https://nca2014.globalchange.gov/
- Living With Water Houston: https://www.houstontx.gov/mayor/Living-With-Water-Final-Report.pdf?fbclid=IwAR3FwzYnpQ0jPlodk86mZKj83ufuU5T5T9S_dhQ-bibhDjY_fSp3i3lndsI
- 2014 National Climate Assessment, Extreme Weather: https://nca2014.globalchange.gov/highlights/report-findings/extreme-weather#intro-section-2
- Texas Water Dashboard from USGS: https://txpub.usgs.gov/txwaterdashboard/index.html
- Rain History from Texas A&M: https://etweather.tamu.edu/rainhistory/
- Wheeler, et al. (2017), Continental-scale homogenization of residential lawn plant communities (Acrobat (PDF) 1.1MB Jan9 20). Landscape and Urban Planning, v. 165, September 2017, p. 54-63 https://doi.org/10.1016/j.landurbplan.2017.05.004