Project Background
The following gives the five-year design plan for Yarbrough Elementary School aimed at reducing water and energy consumption, solving stormwater runoff issues, and increasing students’ understanding of engineering subjects. The school is located on a 10-acre plot of land in the northwest region of Auburn, Alabama. The building occupies 75,000 square feet of the area and is surrounded by manicured green spaces, impervious parking lot, and woods (Figure 1).
Constructed in 1998, the school has 38 classrooms, a multi-purpose room, a media center, a music room, an art room, a venture room, and a computer lab. The school serves anywhere between 375 and 450 students in grades three through five. The school also employs 63 faculty and staff. Since its construction in 1998, the number of attendees has risen. As a result, the water and energy consumption of the school has risen as well. The school is currently consuming nearly 44,000 kwh of electricity per year and 82,000 gallons of water per year. The school board intends to introduce an initiative to the minimize water and energy footprints. Reducing water and energy consumption serves both to lower economic costs and make the school more environmentally sustainable.
Figure 1. Aerial image of the Yarbrough Elementary School site
The school is located in the Chatahoochee watershed. Within the watershed, it is located alongside Sougahatchee Creek in an area of historic flooding. At present, the school experiences high volumes of runoff and flooding during storms. The site has one storm drain located in a low spot near the entrance of the school, Figure 2. From the highest point on the property to the storm drain, there is an average elevation change of 10.8%. The runoff carries wood mulch from the playgrounds and clogs the onsite storm drain, Figure 3. Once a storm event begins, the wood mulch clogs the storm drain and causes the area to flood. The runoff and flooding causes damage to the school grounds and to the ecological integrity of the site. Additionally, the loss of wood mulch increases maintenance costs and requires replacement mulch costing an extra $1,000 per year. Figure 3 shows the open space surrounding the drain. Figure 4 shows the playground area with wood mulch.
Yarbrough Elementary School strives to provide more to its students than just class time. The school provides before and after school care programs, counseling and a wide range of clubs. The school has established extracurricular clubs for students to provide supplemental learning experiences. The current clubs involve sports and recreational activities. However, it is a priority of the school to increase learning opportunities in the fields of science and mathematics. For example, Figure 5 shows one of the school’s student gardens. The garden is entirely maintained by students.
Figure 2. Drain located at low spot which collects mulch and experiences flooding during storm events
The purpose of the following design alternatives is to provide the school with a multifaceted plan capable of addressing all of the aforementioned needs of the school. The plan will reduce water and energy consumption by 10%, resolve runoff problems, and increase learning opportunities for students in the field of engineering.
Figure 3. Mulch and debris from the upper playground collecting around a drain due to stormwater runoff
Figure 4. The upper playground with mulch migrating out of the playground border due to stormwater runoff
Figure 5. The student led gardening project
Design Objectives
The overall intent of the project is to develop a multi-year plan to curtail water and energy usage, improve school grounds, lessen runoff issues and enhance student learning. The plan is a cohesive strategy to evolve the school’s economic, environmental, and social sustainability. Evaluation of the design will be conducted considering the following objectives:
​
-
To form a plan of best electrical and water management practices to decrease Yarbrough Elementary School’s electrical and water consumption by at least 10% each.
-
Create a technical manual for faculty, staff, and students. One section will help readers implement energy conservation practices throughout the school.
-
A second section of the technical manual will contain water reduction strategies for faculty and students.
-
-
To design a landscaping plan to reduce overall site runoff by at least 5% or 0.1 inches for a Type II, 25-year, 24-hour storm.
-
Provide a detailed AutoCAD map of the school property showing all proposed landscaping additions with callouts for use with a landscaping company.
-
Provide a list of native Alabama plants with engineering uses for use throughout the site.
-
-
To produce a STEM learning module for use by faculty containing five lessons relating to the proposed landscaping design.
-
Create a digital portfolio of five educational activities with activity objectives, materials list, procedure, and online references.
-
Constraints
The design must comply with several constraints.
1. First, the design must fit the annual budget of $5,000.
2. Additionally, since Yarbrough Elementary School actively serves in the Auburn City Schools system, any major renovation projects cannot safely or reasonably take place during the 180-day school year while children are present. This affects any design’s outdoor landscaping alterations as any construction cannot interfere with the activities of the faculty or students.
3. Next, the current heating and cooling system can be adjusted but not replaced. Consequently, any attempts to reduce electrical consumption cannot involve the disruption of the HVAC system.
​
4.Further, all designs require an engineering learning component for the students. More specifically, each alternative must contain an interactive learning component to further students’ education in the field of engineering.
5. Lastly, the design must promote aesthetic beauty of the site and preserve the ecological integrity of the land.
Each year, the school must manage a plethora of variables. The number of students, amount of unrestricted budget, and school system requirements can change each year. Due to this uncertainty, a costly or rigid design plan would only serve to hinder the school and prevent the realization of their objectives. Yarbrough Elementary School requires a flexible plan that can be implemented within budget and divided among multiple years without causing interference to the activities of the faculty and students. The final design affords the school the flexibility to execute the designs over the course of multiple years at a time convenient to the school. The school will have the ability to choose from the various components and create the optimal plan to fit their needs and budget.
Design Solution
The design team recommends that Yarbrough Elementary School proceed with the following five design components.
Component 1: “Engineering with Plants” Rain Garden and Rain Barrel Project
A rain garden will be placed in the open grass space on the west side of the school. This rain garden will further alleviate the runoff problems and serve as the engineering learning garden for students. The plants used in the rain garden will all be plants that have applications in engineering. The cost of the rain garden is estimated to be between $3,000 and $4,900 depending on the selected landscaping company. The plant informational plaques will be added and surround the rain garden in phase four. The plaques will allow students to learn about the biosystems and biomedical uses for various native plants. Each plaque will show a photo of the plant, scientific name, growing requirements, and engineering uses. Each plaque is a 5” by 7” weatherproof metal display attached to a 20” stake. Each unit costs $37.99. Figure 6 shows the design of the rain garden.
A cistern and rain barrels will be implemented. The holding cells will act to decrease the amount of runoff caused by the impervious roof surface. The water collected will be used to water the student gardens and teach students about water collection and runoff.
Figure 6. Rain garden design
Component 2: Swales
Three swales will be added to the school grounds in phase two. The swales will ease runoff as well as preventing flooding at the storm drain entry point. The first swale located just below the basketball court will prevent the greenspace from flooding. The swale located above the stairs will help preserve the area behind the school and keep water from running down the stairs. The final swale in front of the playground will help catch any mulch runoff. The collected mulch can be redistributed in the playground. This will also resolve the mulch accumulation issues at the storm drain. The swales will cost approximately $950 and will also function as a runoff catchment to prevent damage.
Component 3: Low Flow Aerators
Low flow aerators will be attached to the indoor faucets throughout the school. The low flow aerators will cost between $70 and $150 depending of the school board’s method of installation. The aerators will save the school $309.32 each year in water costs.
Component 4: Classroom Fans
The classroom fans component would effectively reduce energy usage by 20,418.96 kWh and cost the school $3781.00 for fans in half of the classrooms. The fans would effectively reduce energy consumption by 12%. The addition of the fans would save $2,256. With this amount of savings, the fans will begin saving the school money by year two.
Component 5: Technical Handbook
During the first year, the school’s best management practices plan can begin to be implemented to reduce energy consumption. The practices will include thermostat pre-sets, proper adjustment of window shades, computers being left in low power “sleep mode,” and phasing out of regular light bulbs for LED light bulbs.
Figure 7. AutoCAD map of the changes included in the design
Fig 8. Hydrograph of entire property for a Type II 24-hour storm
Design Method
Technical Analysis
Hydrology Analysis
Prior to designing the channels, swale, and rain garden, the current hydrologic conditions of the site were analyzed. To evaluate the current hydrologic conditions of the site, Excel and HydroCAD were used to estimate the total volume of runoff per month and the peak flow for a 25-year storm event. The rainfall for a 25-year storm in the Auburn area is 7.5” (USDA-NRCS). Excel was used to calculate the total volume of runoff every month for the site and show the land use type distribution. Figure 11 shows the hydrograph of the entire property.
The analysis displayed high areas of impervious spaces or spaces with only grass cover. Both land use types have decreased rates of infiltration (USDA-NRCS). Decreased infiltration in conjunction with the site’s 10.8% slope and location in an area of historic flooding causes the school’s severe runoff issues. To address these problems, the design alternative implements low impact developments to slow down runoff, increase area of infiltration, and redirect runoff to the surrounding woods
​
Rainwater Collection
Rainwater collection cisterns were added to the design as an additional education component. The school has two existing rain barrels which simply need to be installed. Additionally, RainHarvest Systems has a complete cistern system package designed specifically for school educational purposes called the RainFlo Eco School Basic Package. It includes a 350 gallon rain barrel, a gutter filter, a bulkhead fitting, and a hose bibb. The entire package costs $564.95 including shipping (Rainflo).
The installation of these two rain barrels could be integrated into the school’s curriculum as part of a class project or as part of the school’s leadership initiative. This will give the students a connection to the rainwater collection, helping them to truly grasp and remember the concepts. The barrels would be installed on the downspouts near the school’s educational raised gardens so that the water could be used on the gardens. Additionally, water pooling occurs under several of the school’s downspouts, even during dry conditions. This damaging and unsanitary problem will be resolved by the installation of rainwater collection (Figures 12-15).
Fig 9. Pooling water under downspouts near the school
Fig 10. RainFlo Eco School Basic Package from RainHarvest Systems including a 350 gallon tank, rain barrel filter, hose bibb, and bulkhead
Swales
​
A system of three swales in the upper playground area behind the school will both mitigate the school’s erosion issues and redirect runoff away from the school building. The proposed design includes a grass swale installed just north of the basketball court, a swale just north of the mulched playground area, and a swale installed just south of the concrete landing pad at the top of the staircase. Dimensions and holding capacities of the swales were calculated using the TR-55 method and runoff intensity data obtained from NOAA-ATLS.
One swale will be installed north of the basketball court. Grading around the basketball court caused a short hill with a roughly 4-foot elevation change to be formed on the north side of the court. The swale is installed at the bottom of this hill. This swale mitigates the runoff issues on the west side of the playground, keeping the field on the west side from becoming soggy while simultaneously reducing erosion issues.
Another swale will be installed south of the mulched play set area. This swale is designed to intercept runoff coming from the play set area. It will help reduce erosion around the sidewalk area as well as redirect runoff toward the eastern border of the playground. The final swale will be installed just south of the staircase leading up the hill. This swale will function to capture and divert the large runoff volumes which flow directly down the hill toward the school. These flows flood the sidewalks on the south side of the school, cause runoff damage on the hillside, and are a potential threat to the foundation of the school.
The method presented by the North Carolina Department of Agriculture and Consumer Services for swale design was used to size the swales (NCAGR). It was sized to make sure that it could handle the runoff velocity and volume caused by a 10-year, 24-hour storm. The swales have a two-foot-deep triangular cross section graded to the surface at a slope of between 2:1 and 3:1. Using the Mark III Permaculture tool, the swales were priced at anywhere between $3.53 to $10.88 per linear foot (Barnes). The effects of the swales, cisterns, and garden were analyzed using the EPA Stormwater Calculator Software Program Version 1.2.1.0. Figure 11 shows the hydrologic conditions of the site currently. Figure 12 shows the hydrologic conditions after the implementation of all three practices.
Fig 11. Hydrologic conditions before design changes
Fig 12. Hydrologic conditions after design changes
Rain Garden
​
The third feature of the design alternative is the “engineering with plants” rain garden. The rain garden serves as a method of easing runoff issues as well as an engineering learning module for students. All the plants will be native varieties that also have an application in engineering.
Plant plaques will be placed throughout the rain garden to educate students on the applications of plants in the field of engineering. Each plaque will show the photo of the plant, scientific name, growth requirements, and engineering uses.
To further engage students in the garden, student groups could be tasked with maintaining the garden. Faculty could add plant related activities to classroom learning through plant preservation crafts, plant project presentations, or plant journals.
The rain garden, cisterns, and swales were evaluated using the EPA Stormwater Management Calculator. The tool works using the site’s rainfall, land use area, and percentage of area treated with any low impact development. Using the calculator, the implementation of all the green infrastructure methods effectively decreases urban runoff by 8%.
Fig 13. Rain garden design
Water and Energy Reduction
​
Low flow aerators will be used to reduce indoor water consumption and meet the school’s targeted 10% reduction. Current water usage data was unavailable to the team. Water usage data for similar sized buildings and other schools was averaged to estimate Yarbrough Elementary School’s consumption. Based on the consumption rates of other similar buildings and schools, the estimated monthly consumption at Yarbrough Elementary School is 81.9 kgal per month, costing between $270.20 and $308.80 monthly. The nationally regulated flow rate for indoor faucets is 2.2 gpm. Using the national average for hand washing time, bathroom usage, and school days per year, it is estimated that 252,395.35 gallons of water are used by indoor sinks at the school every year. Water used by indoor faucets costs $974.24 per year. Low flow aerators are available in 1.5 gpm. Attaching low flow aerators to all indoor faucets reduces sink water usage from 252,395.35 to 172,258.28 of gallons per year. This saves a total of 80,137.07 gallons.
Auburn University’s School of Kinesiology building is used as a reference for the technical analysis of the fans and appliances. The building’s square footage of 58,000 is closely related to Yarbrough Elementary School’s 65,122 square feet. The electrical consumption (Kwh) per month from January 2016 until December 2016 is provided by Auburn University Facilities Management. Each monthly cost is calculated using the Alabama Power commercial pricing for schools (Alabama Power). A total raw annual is determined to be $40,320 or 0.619 cents per square foot, which is near the national average of 0.67 cents per square foot in the United States (Xcel).
As found in the table below, the number of annual school days, average school hours for Yarbrough, and commercial electric rate for Alabama (Crosby) are used to determine the wattage and energy usage of the fans. To calculate the cost per month, the wattage per month was converted into kilowatts, then calculated using the commercial pricing provided. The average cost per year for the four selected fans is $21.30 per year and $1.77 per month.
​
The handbook provided to the school will further their cause to reduce the environmental footprint. The practices outlined in the handbook will help lower the school’s energy/water consumption and teach better habits to students to be used outside of school as well. Also in the handbook are the five sample lesson plans for faculty. These interactive learning exercises will help students gain a better understanding of the scientific method and inspire greater interest in STEM fields.
Economic Analysis
Economic analysis for the design was conducted to determine the cost of component introduction, financial savings, and payback time. The approximate cost of the cistern system is $564.95. This price accounts for materials and shipping. The swales are estimated to cost $952.72 including labor and materials. This cost was found using the Mark III Permaculture pricing tool (Barnes). The tool considers the size of the swales and the location to estimate the price of materials and labor. The purpose of these components is to slow runoff, increase infiltration, ease flooding, and eliminate the maintenance costs associated with unclogging the storm drain and redistributing mulch. The current cost of maintenance is unknown to the design team, but the cost of mulch redistribution is known to be $1,000 each year. Disregarding the annual maintenance cost, the additions of the swales and rain garden would cost a total of $1,517.67 and save $1,000 each year thereafter. These components would begin generating savings by the second year.
The educational rain garden is estimated to cost between $3,000 and $4,900. The economic evaluation of the rain garden only considers cost because its successful completion of its objectives cannot be quantified. The rain garden would relieve issues and reduce maintenance cost. The rain garden would also improve site ecology. Lastly, its primary purpose is an educational feature. Since maintenance cost are ignored for this report and neither site ecology or educational merit can be precisely quantified, the economic result of the rain garden is its cost. Just as with the rain garden, the economic analysis of the plant plaques is its cost at $37.99 per plaque. Needing a total of 20 plaques, the component will cost $759.80.
To evaluate the economic merit of the low flow aerators, the cost of water for Auburn, AL ($3.86 per 1,000 gallons) was used. The 1.5 gpm aerators effectively reduced indoor water usage by 80.1 kgal annually. At $3.86 per 1,000 gallons, a reduction of 80.1 kgal per year saves the school a total of $309.32 per year. The average cost of the required aerators is $110. Saving $309.32 per year, the aerators will begin saving money by the end of the first year.
Table 3 shows the raw savings from the possible electrical consumption utilizing the fan and HVAC system combination guidelines. In the United States, forty-six percent (Xcel) of electrical consumption and costs are derived from space heating. By taking the annual raw total and percentage allocated to space heating, the portion of the annual bill towards space heating is $18,547.22. Minimally, four to eight percent of heating and cooling costs (IESO) can be cut utilizing the ceiling fans and HVAC system combination. An updated annual raw cost with savings subtracted at each percentage can be found in Table 3. In addition, 3% of energy usage can be saved for each degree the thermostat is lowered or raised in winter or summer, respectively. Thus, a total savings 12% can be calculated if a minimum of four degrees is raised or lowered.
Energy Use Economic Analysis
Economic Analysis of Whole Project
Justification
Does the design meet the stated objectives?
Objective #1: To form a plan of best electrical and water management practices to decrease Yarbrough Elementary School’s electrical and water consumption by at least 10% each
The addition of the low flow aerators to the sink faucets throughout the school reduces indoor water consumption by 31.8% per year. Yarbrough Elementary School’s current water usage is estimated to be 81.9 kgal per month. The school has a faucet in each of its 38 classrooms and faucets in the kitchen, faculty room, and shared bathrooms. The current faucets without aerators flow at the nationally regulated rate of 2.2 gpm. The design proposes the addition of 45 low flow aerators. The low flow aerators decrease faucet flow rate to 1.5 gpm. Using the national averages for hand washing time and bathroom usage, decreasing flow rate on all faucets from 2.2 gpm to 1.5 gpm equates to a total savings of 172.2 kgal per year or $309.32 per year. The cost of 45 low flow aerators including installation is between $70 and $150. With this initial investment, the payback period is one year.
The design reduces energy consumption by 12% with the introduction of fans into the classrooms. The school will save $2225.66 each year due to the reduction in energy usage. In addition to the fans, the best management practices handbook will also decrease energy and water use throughout the school. As lightbulbs require replacement, the school will replace the traditional bulbs with energy efficient LED lights. Surge protectors will be placed in classrooms. Lights will be turned off during vacant hours. Just with behavioral changes, the school will reduce energy and water consumption further.
Objective #2: To design a landscaping plan to reduce overall site runoff by at least 5% or 0.1 inches for a Type II, 25-yr, 24-hour storm
The design plan utilizes landscaping practices to ease runoff. The swales act to redirect runoff starting at the highest point on the property. The runoff can be redirected away from the flooding location and dispersed in the surrounding wooded area. Water caught in the swales will infiltrate into the soil. The rain barrels and cistern will collect rainfall on the roof. The water held in the cistern and barrels is water that would otherwise become contaminated runoff. Using these holding cells, the school reduces the amount of runoff and can make use of the water for irrigation purposes. The rain garden in the eastern area of the property located above the flooding spot acts to slow down runoff, catch any wood mulch carried down the hill, and increase infiltration. The rain garden will improve ecological integrity of the site, slow runoff, catch mulch, and improve infiltration rates. Using the EPA stormwater calculator, these additions to the site will effectively reduce runoff by 5%.
Objective #3: To produce a STEM learning module for use by faculty containing five lessons relating to the proposed landscaping design
The rain garden, in conjunction with the plant informational plaques, provide students with an engineering learning experience. In the rain garden, all plants are native and have applications in biosystems and/or biomedical engineering. The students can be actively involved in garden maintenance. The plaques will teach students about each plant’s scientific name, growing requirements, and engineering use. Faculty can use the garden for various in class learning activities as well.
The lesson plans contained in the handbook can also be used by faculty to incorporate outdoor interactive learning into classroom teaching. The lessons will allow students to learn more about plant anatomy, germination, pollution, and the scientific method.
References
Alabama Power. (2009). “Alabama Power Commercial Pricing.” Alabama Power. Retrieved from http://www.alabamapower.com/
Aluma Photo Plate. (2018). “Tree Plaques and Plat ID Markers.” Retrieved from https://www.alumaphoto-plateco.com/
​
Amee. (2016). “Garden Printables for Kids.” Retrieved from https://madamedeals.com/
​
Barnes, Douglas. (2015). “Mark III Permaculture Swale Calculation.” Retrieved from https://www.permaculturereflections.com/swale-calculator/
​
Crosby, Kate. (2013). “Powering Down: A Toolkit for behavior based energy conservation in K-12 schools.” Center for Green Schools. Retrieved from http://www.centerforgreenschools.org/sites/default/files/resource-files/Behavior-based-Efficiency.pdf
​
DOE (Department of Energy). (2016). “Fans for Cooling.” Retrived from http://energy.gov/energysaver/home-cooling-systems/fans-cooling
​
Energy Star. (2017). “Purchasing Energy Saving Products.” Retrieved from https://www.energystar.gov/buildings/facility-owners-and-managers/existing-buildings/save-energy/purchase-energy-saving-products
​
Homewyse Consulting. (2017). “Landscaping and Home Additions.” Retrieved from https://www.homewyse.com/
​
IESO (Independent Electricity Systems Operations). (2014). “Facts on Ceiling Fans.” Ceiling Fans Efficiency Facts-Save on Energy.” Retrieved from https://saveonenergy.ca/Consumer/Conserve-and-Connect/2014/The-facts-on-ceiling-fans.aspx
​
King County. (2016). “Stormwater Pollution Runoff.” Retrieved from https://www.kingcounty.gov/services/
​
Louise. (2015). “Flower Petal Suncatcher.” Retrieved from http://www.messylittlemonster.com/
​
NCAGR. “8.0 Vegetated Swales.” North Carolina Department of Agriculture and Consumer Services. Retrieved from http://www.ncagr.gov/SWC/costshareprograms/CCAP/documents/Chapter8-VegetatedSwales.pdf
​
Rain Harvest Systems. (2018). “RainFlo Eco School Basic Package.” Retrieved form www.rainharvest.com/rainflo-eco-school-basic-package.asp
​
Seedland. (2015). “Bermuda Grass Seed For Lawn, Turf, Pasture.” Retrieved from www.bermudagrass.com/
University of Minnesota. (2018). “Building Soil Berms.” Retrieved from www.extension.umn.edu/garden/landscaping/implement/soil_berms.html
​
USDA-NRCS. (1986). “Calculating Stormwater Runoff.” Retrieved from http://riverlink.org/wp-content/uploads/2014/01/CH-1-3CalculatingyourStormwaterRunoff.pdf
​
WaterRich. (2017). “Berms and Swales.” Retrieved from http://riverlink.org/
​
Xcel Energy. (2007). “Managing Energy Costs in Schools.” Xcelenergy. Retrieved from https://www.xcelenergy.com/staticfiles/xe/Marketing/Managing-Energy-Costs-Schools.pdf