LEED SS Credit 6.2 Stormwater Design- Quality ControlRussell Auwae, Jamie Brocker, Carolyn Finnochi, and Dianna Zimmerman

Abstract

Freshwater is a finite resource. Impervious surfaces like sidewalks and paved roads block the infiltration of storm water into the ground. Without capturing and/or treating, stormwater runoff pollutants are carried to nearby waterbodies harming the environment, and a waste of a precious resource. Miami University has the potential to capture and treat stormwater runoff before it enters nearby waterbodies by implementing several best management practices (BMPs), which include: rain gardens, cisterns, vegetation buffers, bioswales, and green roofs. Implementing these BMPs will improve the quality of stormwater runoff and earn Miami the LEED SS Credit 6.2: Stormwater Design- Quality Control. However, it is not known where on campus these BMPs should be implemented. Placement of these BMPs depends on soil type, slope, and land availability. Thus, our objective was to provide Miami a map of where BMP favorable areas exist using soil, slope, and landscape maps.

IntroductionStorm drains and rain gutters do not go to wastewater treatment plants but instead

flow into streams and other natural features without treatment. Storm water easily carries hazardous pollutants into the water surrounding Miami University. These pollutants include fertilizers, oil, grease, and other chemicals from cars and motor vehicles, bacteria and pesticides from pet waste and leaking septic tanks, and more. Fish and other aquatic life are affected by the pollution as excess nutrients create an inadequate supply of oxygen and chemicals such as antifreeze from cars are extremely toxic and can be life threatening. In addition, impervious ground cover does not allow enough storm water to flow back into the ground to recharge the water table. The water that does make it back to the ground is also highly contaminated with pollutants.

In order to earn LEED SS Credit 6.2, Miami needs to promote infiltration of the runoff before it reaches the stormwater drains and promote treatment of the runoff using best management practices. More specifically, 90% of the average rainfall must be captured or treated by the implemented BMPs. Furthermore, these BMPs must be able to remove 80% of the average total suspended solids. Thus, our goals and objectives for Miami University include:

*Increase infiltration and groundwater recharge.*Conserve, reuse and recycle stormwater.*Improve the stormwaters quality.*Map where BMP favorable areas exist.

Best Management Practices (BMPs)

There are several BMPs for reducing the amount of constituents in stormwater runoff, which includes: vegetation buffers, green roofs, rain gardens, and rainwater

harvesting cisterns. Our goal is to implement those BMPs that are cost-efficient and able to incorporate into new infrastructure on Miami University Campus.

Rainwater Harvesting Cisterns

Rainwater harvesting cisterns are catchment systems that store roof runoff for irrigation use (psp.wa.gov, 2005; water.epa.gov, 2012). This approach decreases the amount of runoff and the need for filtration of runoff. Several universities have implemented these catchment systems, which include: Democritus University of Thrace (Gikas and Tsihrintzis, 2012), Fu Jen Catholic University, National Yang Ming University, National Taiwan University, Shih Hsin University, Chinese Culture University, Jinwin University of Science and Technology, National Chenchi University (Chiu, 2012), and Emory University (Lynch and Diestch, 2010).

The cost of rainwater harvesting system depends on the location, installation, and the amount of potential rainwater being collected. For example, the installation cost for a building around 300 square meters is about $2,000-$30,000 (rainharvest.com, 2013; rainwaterharvesting.org, 2013) . A system serving a large industrial facility may cost around $100,000 to engineer and construct. For Miami University, since we have a large campus, it is impossible to install the system for all the buildings. Therefore, it is import for Miami to determine which buildings need this system the most and where collection of potential rainwater is highest. Currently, Miami is implementing this at the new Armstrong Center.

Rain Gardens

Rain gardens are areas with specific soil and vegetation types that allow for infiltration and retention of stormwater runoff (psp.wa.gov, 2005; water.epa.gov, 2013). They are particularly useful along sidewalks, in parking lots, and open spaces. This approach decreases the amount of pollutants in runoff, allows natural remediation by soil and plants, and percolates to recharge groundwater. Several universities have implemented rain gardens on campus, which include: Villanova University (Jenkins et al. 2010), Lawrence Technological University (Carpenter and Hallam, 2010), and the University of Delaware (Grehl and Kauffman, 2007).

Installation of a raingarden consists of knowing the surrounding soil type, slope, as well as which plants to grow and the economical design to complement the area (malvern.org, 2013).The cost of a rain garden usually ranges from $15-$25 per square foot (appliedeco.com, 2013). This price includes installation, plants, design, and growth media.

Vegetation Buffers

Vegetation buffers are strips of vegetation that are typically installed before water inlets that allow for natural remediation of runoff by plants and soil (psp.wa.gov, 2005; water.epa.gov, 2013). Their function is similar to that of the rain garden, but usually requires less maintenance and is not high on aesthetics. This method is used highly used

in fields of natural resource management and agriculture for its simplicity and effectiveness (Dosskey, 2001; Yuan et al. 2009; Richardson et al. 2012).

The land for vegetation buffer must be available. If the cost of the land being developed is high, then buffer will have a high cost. Also, the vegetation buffer needs to be maintained every half year or every year (cfpub.epa.gov, 2013; files.dnr.state.mn.us, 2013). If the buffer area is very large, maintenance might be very costly.

Green Roofs

Green roofs are green spaces established on rooftops of buildings to capture and filter rainwater, and are also aesthetically pleasing (psp.wa.gov, 2005; water.epa.gov, 2013). One example of its efficient use is at Portland State University (Spolek, 2008). The university is able to reduce costs associated with cooling the building and irrigation, and it provides an outdoor laboratory for students to study vegetation.

On average, the cost of a green roof is around $15-$20 per square foot; this does not include the maintenance fee for each year (lid-stormwater.net, 2013). Furthermore, installing green roofs requires replacing the original ceiling to a waterproofing ceiling which is costly (en.wikipedia.org, 2013). Currently, Miami is incorporating green roofs on the newly developed portion of Western Campus.

Implementation of BMPs

Implementing any one of these BMPs on this campus will also help earn LEED SS Credits 5.1: Habitat Preservation/Restoration, 5.2: Open Space, 6.1: Stormwater Design- Quantity Control, and WE Credit 1: Water-efficient Landscaping. These BMPs prevent soil erosion, water pollution, and flooding events. In addition, BMP benefits include: reduced landscape maintenance, potential bird and butterfly habitat, campus beautification, living laboratory and sustainability demonstration, and most importantly, conserves energy and money. Landscape maintenance can be reduced by installing low maintenance plants, yet are still favorable for bird and butterflies. Maintenance can be further reduced by having student and/or community involvement, which helps serve as a public demonstration and outreach tool for communicating and teaching sustainability. Lastly, energy and money would be conserved due to the reduction in needing to capture and treat stormwater, and reduce the purchasing of water for landscaping.

Site Characteristics

Pervious Percentage Area

Setting a benchmark of 80%, Miami should seek to improve the pervious percentage areas of the following watersheds: South Patterson, Campus Avenue, North University Avenue, Chestnut Avenue, North Patterson, North Four Mile Creek, Varsity Athletic Area, and Millet (Table 1). These watersheds currently have pervious percentage areas ranging from 25- 73%. South Patterson Watershed is currently experiencing most

of the development on the Miami Campus; therefore, implementation of these BMPs should be focused on this watershed (Fig. 1, 2).

Table 1: Impervious and pervious percentage area for Miami University (KKG, 2011).

Figure 1: Campus area divided up in watersheds (KKG, 2011).

Figure 2: Land cover of campus area (KKG, 2011).

Soil Type and Slope

Soil type is quite uniform across campus consisting of B/C soils (Fig. 3), which is predominantly glacial till (Table 2). Plants that favor soils that consist of mostly silt and clay should be considered during installation of these BMPs. The campus area is relatively flat (Fig. 4). There are no foreseeable restrictions to BMP construction due to soil type and slope.

Figure 3: Soil type of campus area.

Table 2: Soil boring report with description of soil characteristics at different depths (KKG, 2011).

Figure 4: Slope of campus area (KKG, 2011).

Currently, Miami University has 229.1 acres of impervious surface and generates approximately 10 million cubic feet of runoff. In order to fulfill LEED Credit 6.2, about 9 million cubic feet of runoff would need to be captured. The suggested BMPs will help Miami University capture the required 90% of runoff.

Recommendations

Since majority of the area of North University and Campus Avenue Watersheds is residential area, a partnership between needs to be established between planners and developers for Miami and the Oxford community toward sustainable development and implementation of BMPs (Fig. 5). Areas that are mostly urban, that Miami owns, should implement green roofs, porous concrete, and rain gardens (Fig. 5). South Patterson Watershed has plenty of open space to implement all the BMPs mentioned previously.

Special attention should be given to the area surrounding the creek (Fig. 5). This area experiences soil erosion during every rain event. Vegetation buffers and rain gardens should surround this area to reduce the velocity of rainwater entering the creek.

Figure 5: Examples of potential placement of BMPs around campus.

Miami currently has no water quality monitoring system. This makes determining whether Miami’s water quality is improving or not an impossible task. Rainfall measurements can be taken by installing rainwater gauges around campus. These measurements will help determine how much rainfall Miami’s Campus receives. In addition, automated water sample collecting pumps should be installed at all the outfall points indicated (Fig. 6). By collecting water samples at these outfall points, Miami will be able to determine whether it has improved the quality of stormwater runoff, which would provide analytical evidence and support for LEED SS Credit 6.2. Funding for equipment, placement, and lab analyses can be found through the Environmental Protection Agency (EPA, 2013) and National Science Foundation (NSF, 2013). This campus-wide water monitoring system would make a great research project for Miami faculty and students to get involved in.

Future Initiatives

Miami University planners and developers need to commit to the following: All new development on campus will consider stormwater BMPs Increase the number of rain gardens and pervious surfaces to allow water

infiltration and groundwater recharge

Figure 6: Route of stormwater pipes and locations of outfall (KKG, 2011).

Conclusion

All of the suggested BMPs have similar functions, and so, implementation of any of the BMPs would be a positive step forward for Miami University towards a green and environmentally conscious campus. It is in Miami’s best interest to implement these BMPs and become known as a “green” campus in order to stay competitive with other universities. These BMPs prevent soil erosion, water pollution, and flooding events. In addition, BMP benefits include: reduced landscape maintenance, potential bird and butterfly habitat, campus beautification, living laboratory and sustainability demonstration, and most importantly, conserves energy and money. Landscape maintenance can be reduced by installing low maintenance plants, yet are still favorable for bird and butterflies. Maintenance can be further reduced by having student and/or community involvement, which helps serve as a public demonstration and outreach tool for communicating and teaching sustainability. Lastly, energy and money would be conserved due to the reduction in needing to capture and treat stormwater, and reduce the purchasing of water for landscaping.

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