INNOVATE + INFILTRATE + IMMERSE

TEAM D3

STUDENT NAMES + MAJORS:AUSTIN BOWMAN | Landscape Architecture + GIS Certificate

SHARNA CHOWDHURY | Landscape ArchitectureVIRGINIA FALL | Landscape Architecture + City Design Certificate

ANNA GRACE FITZGERALD | Landscape ArchitectureSIMON GREGG, EI, LEED GREEN ASSOCIATE | Biological & Agricultural Engineering

ANDREW HARRELL, EI | Landscape Architecture + Watershed Restoration CertificateMONIQUE KOWALIK | Architecture

KENNETH JACKSON | Landscape ArchitectureELLIE LERNER, SITES AP | Landscape Architecture

FACULTY ADVISOR:CARLA DELCAMBRE, PLA, ASLA | Landscape Architecture Department

The College of Design (COD) at North Carolina State University (NCSU) is located on the eastern edge of the historic campus. Students in the College of Design spend most of their time within three buildings: Brooks Hall, Leazar Hall and Kamphoefner Hall. The formation of these buildings and three adjacent residence halls creates a 3.4 acre community; this area of campus will be referred to as the COD Block. Unkempt, monoculture plantings surrounding a large brick pit and scattered benches are indications that the space has transformed over the years without a clear plan. While there are spaces to rest, eat and learn, this area is not a reflection of the innovation and technology that NCSU is known for. While this space meets the daily operational needs of students and faculty, there are opportunities for intervention to improve this area of campus from a technical and programmatic perspective in regards to social function and green infrastructure strategies. Our interdisciplinary team, comprised of students from Landscape Architecture, Architecture, and Biological and Agricultural Engineering, is proposing a design that implements various forms of green infrastructure in measured, artful and sustainable ways. Our proposal seeks to support the Physical Master Plan guiding principles by implementing innovative methods being pursued in the design profession. The educational and interactive nature of this space is intended to embody the missions of the Colleges of Design, Engineering, and Horticulture at NCSU, and the green initiatives set forth in the Physical Master Plan and Sustainability Strategic Plan.

ABSTRACT

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The NC State College of Design is a Bauhaus style landscape situated within the historic part of our campus and is home to landscape architects, industrial designers, architects, graphic designers and students from many other disciplines. The College of Design is one of ten different colleges at NC State, existing alongside the Colleges of Engineering, Sciences, Natural Resources and many more. The diversity in educational opportunities has positioned our university as an institution for world-class research and

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PROJECT DESCRIPTION

Figure 1. Proposed site design

technology. The COD Block that we are focusing on for this project is located at the easternmost edge of our campus and is a gateway to the campus when coming from downtown Raleigh and the up-and-coming Dorothea Dix Park. The centralized courtyard made sense, in context, when it was constructed, but no longer functions as a comfortable and inhabitable space for students and faculty. The abundance of brick, century oaks and patchwork landscape does not accurately represent the design and engineering for which NC State is so well known. We see this as an opportunity to fully utilize the brain power occurring within the landscape architecture, engineering, horticulture and architecture classrooms and serve as a catalyst for further development within the University and to showcase this innovation to a larger audience. Our design seeks to set a higher University standard for sustainable building and landscape planning. We want this area of campus to serve as an example of outstanding interdisciplinary collaboration and design through the use of regenerative systems, the increase of perviousness, the adoption of a diverse and ecologically mindful planting palette, and the integration of best management practices with socially considerate designs. We believe that this design will lead the discussion as a precedent for future projects on campus, and will allow users to engage with stormwater in an artful and progressive way. As our team practically lives on the site, we came into the project fully equipped with a list of issues that needed to be addressed in our design. The existing COD Block has 63% impervious surface made of either brick, concrete or rooftops. During rain events, large puddles show signs of brick subsidence. A history of urban infill redevelopment and a lack of infiltration generates large runoff volumes and peak discharges. During summer, radiant heat from the bricks, concrete paths, and large Bauhaus era buildings creates an uncomfortable environment and contributes to the urban heat island effect. Many existing planting beds are remnant of a historic road

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that transected the site and the plants within this area lack diversity. Redevelopment has encroached upon the root zones of the historic allee and compromised heritage oak integrity. These large trees, beloved by all at NC State, are showing signs of disease and old age and are a liability to the structures as well as people below. Framing our design within the SITES guiding principles, we sought to “design with nature and culture” by promoting a more enjoyable human experience through the use of green infrastructure, and “foster environmental stewardship” through the implementation of a Living Laboratory Garden, which also strengthens the university’s commitment to extension, as a land-grant institution. Throughout our process, we also used a “systems thinking approach” by analyzing stormwater control measures that would work with the larger system put into place by campus planners as well as the City of Raleigh.

PROCESS

Figure 2. Students, faculty, staff, and practicing professionals participated in a charette at the beginning of our design process to give input on suggested improvements.

Due to our backgrounds in Landscape Architecture, Environmental Sciences, Biological and Agricultural Engineering, and Environmental Engineering, we came prepared with an understanding of interventions that could be beneficial to this site. As part of our process, we sought to engage with the community to determine how other stakeholders visualize the future of the site. Considering the feasibility of this proposal is largely determined by the facilities division, planning staff from the Office of the University Architect, and campus partners’ approval, we maintained opened dialog with several members of facilities staff and included as many representatives at each stage of design process. Facilities planning representatives, housing staff, university faculty, extension specialist, architects, students, and residents of the COD block dormitories all participated in design charrettes and a more intimate stakeholder group participated in an intermediate design pin-up. Stakeholder feedback and priorities informed design decisions providing additional consideration for post-construction stormwater management and monitoring. Our team worked to understand the unique history of the site as a former roadway corridor and the potential future expansion of academic buildings using the Physical Master Plan as a framework for future campus development. We learned from facility planners where expansions would likely take place and this knowledge provided reasonable boundaries of intervention in hopes that, if built, the proposed design would remain an

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integral part of the landscape. Consultation from Horticulture and Natural Resources faculty, Dr. Barbara Fair, CA and Anne Spafford, MLA, supplemented the fields not represented by students on our design team. Horticulture faculty provided valuable information on identifying which existing vegetation is performing well and should be preserved and which should be removed or reconsidered for placement. Through research and conversations with arborists and horticulturists, we were able to select a diverse plant palette, following the principle that no more than 5% of the plantings on a site should come from the same genus. While selecting plants for the site, our team researched appropriate vegetation for our eco-region that would manage precipitation on site, promote social connectivity and support mental well-being of the surrounding community. (SITES v2) Soil sample analysis, completed by the North Carolina Department of Agriculture Soil and Crop Sciences, yielded useful information about soil composition, health, and provides guidance for remedial measures to ensure plant health and vigor. The proposed sustainable design solutions are primarily focused on stormwater management, but have the opportunity to positively influence the social interactions among the students, faculty, staff, and the surrounding community. This campus site is a microcosm of topics and discussions explored within our curriculum and provides an opportunity to create an example of the innovation pursued in our fields. The site, composed of three sub-watersheds, drains to Rocky Branch, a C5 urban stream (Rosgen). The receiving reach was restored between 1998-2010 during a 3-phase multi-million dollar restoration. This site allows our team to pursue various forms of green infrastructure while designing with innovation and passion as we bring restoration efforts from the stream to upland areas creating templates that can be replicated at other sites on campus. It is important to our team to showcase the value of collaboration between disciplines and to highlight the potential for sustainable practices as a social, environmental, and economic benefit.

Figure 3. The student team organized a plant walk with faculty from Horticulture and Natural Resources to assess the plant health of existing plants and discuss the possibilities with new planting.

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“THE BLOCK” “The Block” represents the entirety of our project site in its urban context. Some portions of our campus are rich with open lawns and dense vegetation while others, like this site, are much more urban. Using the SCS Curve Number Method, we calculated a composite Curve Number of 93 (typical 100% impervious surface has a Curve Number of 98) with 63% impervious (NRCS). “The Block,” due to storm sewer delineations, includes three subwatersheds, all converging down slope from our site before routing to Rocky Branch. With discrete storm sewer networks, subwatersheds provide the opportunity to make targeted interventions that would operate collectively to reduce runoff volumes and

pollutant loads before leaving the site and enters the larger system. We calculate that our proposal will reduce imperviousness by approximately 22%, from an estimated 63% impervious to 49% total imperviousness corresponding to a disconnection of 21,000-sf of imperviousness and a CN improvement to 89. Throughout the site we propose to aerate and decompact planting beds while incorporating, at most, 10% organic compost to improve soil physical and chemical structure. We propose increasing the amount of plants and planting diversity. A diverse planting palette will provide ecosystem services beyond the stormwater management initiatives, like attracting pollinators and other beneficial insects, reducing the heat-island effect, improving health and wellness and providing a more welcoming environment for human interaction. In addition to improving the plant material, our team explored structural Stormwater Control Measures (SCM) across the site referenced as “The Pit”, “The Yard”, and “The Spine.”

Figure 5. A cross-section from Kamphoefner Hall (left) to Brooks Hall (right).

Figure 4. Key map

Due to its recessed nature, “The Pit” provides no respite from excessive heat and sun exposure, and is void of enjoyable breezes. These factors create a fishbowl kind of environment thus being the least conducive to social interaction within our site. “The Pit” has become our highest priority for intervention and has the most potential for social engagement through the interactive capabilities of moving and capturing water within the site in a Regenerative Stormwater Conveyance (Whyte, 1980). Regenerative Stormwater Conveyance (RSC) is a

combination of urban stormwater treatment techniques and stream restoration practices that provide dual benefits of treatment and conveyance (Flores et al.; WVDEP). This technique provides treatment via settling, infiltration, and shallow interflow. Combining shallow pools, riffle weir grade control structures, vegetation, and porous media; RSCs are typically designed to safely convey 100-year flows (WVDEP). There are generally three configurations found in the literature, they are characterized by the Rosgen A, B or DA stream classification and are suited to stabilize entrenched ephemeral or perennial gullied headcuts or eroded outfalls with valley slopes up to 10% or adapted to greater slopes while restoring floodplain connectivity and riparian wetland hydrology (Flores et al., 2012). The proposed RSC will employ a series of boulder cascades-pool sequences to safely convey flows downslope into “The Pit.” On “The Pit” floor a created channel will end in an infiltration area, or sand filter, that is underdrained to a sump and pumped into a storage cistern for use as irrigation in planting beds throughout the project area. This combined treatment system will serve to reduce pollutant loads and runoff volumes by, conservatively, 50% and 60%, respectively. This system will also serve as a showcase of innovation incorporating natural channel design into a highly urban setting to provide ecological and social uplift. Increased planting and the creation of

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“THE PIT”

Figure 7 & 8. The existing condition in “The Pit” contains a high percentage of hardscape contributing to the urban heat island effect.

Figure 6. Key map

a water feature will serve to add texture, structure, and intrigue within “The Pit” while cooling the area via evapotranspiration. Stormwater flows will be diverted from an existing upslope manhole with a weir to ensure design flows are not surpassed. The RSC design feasibility was assessed considering a capture area of approximately 18,000-sf including portions of Brook’s roof and the Spine brick and landscaping. The NRCS Rational Method was used to determined the peak discharge from a 1-year 5-min intensity storm for the proposed capture area (NRCS). The determined peak discharge of 1.61-cfs was used as the design discharge for the RSC channel cross-section. Using Manning’s equation, an approximate slope of 0.4-ft/ft, and estimated channel roughness of 0.04, channel bankfull depth and width were determined to be 0.25-ft and 0.95-ft, respectively. The use of sand or media filtration prior to storage will reduce suspended

sediment and prevent excess sediment deposition within the cistern. Design feasibility was assessed considering a 1-in water quality event resulting in a capture volume of approximately 1010-cf. Considering a media filtration rate of 1.5-in/hr and a ponding depth 8-in, the proposed infiltration area needed would be approximately 130-sf and would infiltrate completely within 5.5-hours. A pretreatment sump can also be employed to capture additional sediment before storage, if desired. Inclusion of

an overflow or bypass device that is connected to the existing storm sewer will be required for safety and integrity purposes. This system should function as a showcase feature and can be designed to operate on solar power; hydraulic efficiency will reduce pump demand and allow storage and distribution to planting to be accomplished via solar photovoltaics deployed in the vicinity. Furthermore, the system, with a rain sensor, could be programed to operated as a water feature during no flow times by pumping water to the top of the RSC and allowing it to cascade and return to storage. Regenerative Stormwater Conveyance is an innovative technique for stabilizing streams and eroded channels while providing stormwater treatment. They have not been extensively studied and what literature exist is widely scattered as to their pollutant and volume reduction performance. This system can be employed in conjunction with the living learning labs to allow students to understand what aspects go into their design and gain hands-on experience with these types of innovative SCM. Students could conduct experiments and engage in monitoring to understand how the system performs over time. In conjunction with the departments of Landscape Architecture and Biological and Agricultural Engineering, the implementation of this system on our campus could provide critical source data to fill the gap in literature about these systems, exemplifying the university’s mission statement.

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Figure 9. Proposed RSC design within “The Pit”.

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“THE YARD” The “Yard” is a space that exists between three Residence Halls on our site, lending to more residential social behaviors and fostering a relaxed communal feel through its use of a large lawn, swings, varied plantings, and a large gazebo. Our proposal suggests adding more sustainable planting and incorporating the flow of water into a larger system that better manages the site on a more encompassing scale. By connecting the stormwater of this area to a larger system, there is potential to capture, clean and recycle that water, saving the University a significant amount money that would

otherwise be allocated to irrigation and planting maintenance. Using a consistent planting palette that is both low maintenance and high performing also contributes to a more cohesive space, representative of the larger systems at work. This consistency also visually communicates a continuation of the communal spaces between dormitories and academic buildings as a unified space. With Welch and Syme Residence Halls, we are proposing disconnecting impervious surfaces to allow for stormwater infiltration both in the bioretention cell along Pullen Drive and through the lawn space flanking the buildings. Based on our estimates, this approach increases infiltration by 14%. Based on the soil data we collected, this lawn space can be decompacted to allow more absorption of water, further increasing infiltration. In addition, the added plant material will help with the need to increase infiltration and also to help unify the space by giving it an aesthetic identity.

Figure 10. A section between Syme, Welch, and Gold Residence Halls illustrating the communal yard space unified by a consistent planting palette.

14% INCREASE IN INFILTRATION

Figure 9. Key map

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“THE SPINE”The existing conditions of “The Spine” operates on the edge of two watersheds, but the social nature of the space is a singular corridor. Our design proposes unifying the flow of water to converge with the stormwater system located downhill on our site’s edge. Capitalizing on the existing manhole, the proposed weir installation directs water from “the Spine” ultimately providing more flow of water for the RSC system for added effect and functionality. This portion of North Carolina receives more than fifty inches of rain per year and eleven inches in a 500 year storm event. This provides ample opportunity to incorporate directional trench drains in an educational and artful way to expose the flow of water in a rain event so students can see where the water moves and is collected, highlighting this intentional directionality and unification of space. The extensive hardscaping along this corridor makes for unrelenting heat in the summer and cold in the winter. In addition, there are numerous places that puddle, collecting water after a rain. By removing portions of the brick surfaces and replacing them with permeable pavers, the ground will become more pervious, while remaining ADA compliant,

and will create a more comfortable sensory experience through absorbed sound and textural variation, thus encouraging more use by students and faculty.

Figure 13. Rendered perspective of new immersive social area on ‘The Spine’

Figure 12. The existing condition of“The Spine”.

Figure 11. Key map

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RESILIENCY + PERFORMANCE To assess some performance aspects of our design we used SITES v2 Native Plant worksheet and the SCS Curve Number Method. The SITES v2 Native Plant Score for our design is 68.6 which would qualify for the highest amount of points in SITES v2. We determined the site in its current state would capture and treat less than 5% of a 1-inch storm event. Using the SCS Curve Number Method, we determined the proposed design would capture and treat 92% of a 1-inch storm event. Primary methods of treatment would be through conveyance and capture, increased plant uptake, and evapotranspiration. Annually this design would capture and treat approximately two Olympic size swimming

pools, or 183,300-cf, of stormwater. The installation of a large cistern in “The Pit” would allow for water to be reused for irrigation purposes in the surrounding planting beds and the two lawns on the site. Calculations can be seen in the calculations appendices. Additional performance benefits include over 7000-sf of primarily native plantings that attract pollinators and a 22% reduction in impervious surfaces while maintaining accessibility across the entire site. NCSU’s Department of Landscape Architecture hosts a Landscape Performance + Metrics course annually that could perform annual performance evaluations, evaluating soils, plant health, and drainage. Additionally, if this project were to be carried out by the University through our Design/Build Program performance monitoring could be integrated into the contract. The idea is this project becomes an experiment to determine what works and what does not on our campus. The location of the site and its unique blend of academic, professional, and residential settings would allow for both passive and active education of how green infrastructure can improve a communal space. Educational signage and courses using the site as a living laboratory would allow students to also understand the benefits of green infrastructure on campus through the pollinator habitat, native plant communities, and reduced urban heat island.

Figure 13. Sustainable SITES Native Plants + Communities Worksheet

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CONCLUSION + FEASIBILITY We estimate from precedent cases and research of vendors for materials this project would cost between $250,000 and $300,000 not including labor. While this is more than is typically spent on capital projects for the landscape, NC State has a history of promoting student learning by actively engaging them in projects around campus to benefit the student community and enable more hands-on experience. Over the last seven years, the Department of Landscape Architecture, in partnership with University Housing,Landscape Construction Services, Grounds Management, and University Architects Office, has collaborated on a $250,000 contract to improve the conditions of landscapes on campus through the Design+Build program. Student designed and built work stemming from this program includes the gazebo in “The Yard”, the rain garden behind Syme Hall, and many other residence hall landscapes across campus. These projects are widely regarded as successful by University Housing as well as the students who use the spaces every day. Due to the overwhelming success of this partnership between Housing and the Department of Landscape Architecture, a similar contract for $250,000 has been signed for an additional five years. The Department of Landscape Architecture will offer a Design+Build class in Spring, 2018 that will focus on a smaller site within the COD Block in front of Syme Hall adjacent to “The Yard.” Students will use this proposal as initial research for the implementation of an SCM on the site. While these built works are a sign that the University is moving forward with green infrastructure, the scattered projects seem to exist independently and are not a part of a larger unified system. Our plan not only celebrates the existing projects as integral parts of the COD Block but also gives them more purpose and context. Our design provides the Design+Build program with realistic ideas that could be implemented on this site, as well as other sites across campus. The amount of research and deliberation that occurs for green infrastructure projects of this nature to become realized can be daunting, but our proposal provides an excellent foundation for the work to continue during the coming semester, and in future Design+Build projects. In the future, we also hope to include more industry partners in this process including professionals from the City of Raleigh and local Landscape Architecture and Engineering firms.

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CALCULATIONSHydrology estimations were performed using the SCS Curve Number (CN) Method and the Simple Method, with the largest volume, or most conservative values used in further consideration. The SCS CN approximation of runoff volume is calculated as follows:

Where CN is the composite curve number determined for the project area based on land use, topography, and vegetation, P is the design rainfall depth, S is the maximum surface storage, or initial abstraction, and Q* is the estimated runoff volume. The Simple Method (SM) is determined as follows:

Rv=0.05+0.9*IaDv=3630*Rd*Rv*A

Where Rv is a unitless runoff coefficient, Ia is the unitless impervious fraction, Rd is the design storm depth (in), A is the drainage area (acres), and Dv is the design volume (cf).

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REFERENCESFlores, H., Mcmonigle, D., & Underwood, K. (2012). Regenerative Step Pool Storm Conveyance ( SPSC ) – also known as Coastal Plain Outfalls, (June 2009), 1–36.

NRCS. (1986). Urban Hydrology for Small Watersheds TR-55. USDA Natural Resource Conservation Service Conservation Engineering Division Technical Release 55, 164. https://doi.org/Technical Release 55

Rosgen, D. L. (1994). A classification of natural rivers: Reply. Catena, 22(3), 169–199.http://doi.org/10.1016/0341-8162(94)90001-9

SITES v2 reference guide: for sustainable land design and development. (2014). U.S. Green Building Council. Austin, Texas: Sustainable Sites Initiative.

West Virginia Department of Environmental Protection. (2012). West Virginia Stormwater Management & Design Guidance Manual, 1–22.

Whyte, William H. The Social Life of Small Urban Spaces. Washington, D.C: Conservation Foundation, 1980. Print.

The NRCS Rational Method was used to determine peak discharge rates as follows:Qp=CiAWhere C is a unitless runoff coefficient, i is the design rainfall intensity (in/hr), and Qp is the peak discharge (cfs).

Manning’s Equation was used to estimated RSC channel hydraulic geometry parameters bankfull width and depth through iteration. Manning’s equation is as follows:

Q=(1.486/n)*A*(R^(⅔))*(S^(½))Where n is a unitless coefficient for channel roughness, A is the channel cross-sectional area (sf), R is the hydraulic radius of the channel (ft/ft), S is the channel slope (ft/ft), and Q is discharge (cfs). Bankfull width and depth parameters were varied until the estimated peak discharge from the Rational Method approximated the discharge determined by Manning’s equation.