Doctor of Philosophy, The Ohio State University, 2024, Food, Agricultural and Biological Engineering

Worldwide urbanization and the concurrent increase in impermeable surfaces, such as parking lots, driveways, sidewalks, and other structures, have led to challenges managing runoff in cities. Improperly managed stormwater poses threats to public health, private property, and the environment. Countries worldwide are adopting the use of nature-based approaches known as green infrastructure (GI) to holistically treat environmental stressors resulting from urban development. GI is designed to mimic the natural, pre-development hydrology of the developed area while concurrently improving runoff quality. There are several GI approaches, including permeable pavements (PP), bioretention cells (BRC), and constructed stormwater wetlands (CSW), which can reduce runoff volume, delay and extend runoff timing, improve discharge water quality, and mitigate peak runoff rates from highly impervious catchments. PPs have been used worldwide for decades, but these systems remain infrequently implemented for stormwater management because of ambiguity related to maintaining their long-term hydraulic functionality due to clogging which reduces the PP surface infiltration rate (SIR) and therefore its performance. Measurements of the SIR can inform the extent of clogging, but at present there is a dearth of guidance on how to incorporate SIR data into dynamic PP maintenance plans. In the first chapter of my dissertation, I conducted a review of existing guidance documents to describe the current state of practice for SIR measurement methodologies, PP maintenance guidance, and the use of SIR outcomes to inform PP maintenance plans. Standard and alternative SIR assessment methodologies were described and compared, and modifications and recommendations were provided to clarify testing methods, streamline testing efficiency, and reduce the burden of SIR monitoring. Suggested modifications included requiring regular SIR testing, shortening the duration of SIR tests, and allowing for usage of mo (open full item for complete abstract)

Committee: Ryan Winston (Advisor); Jay Dorsey (Committee Member); Jon Witter (Committee Member); Jiyoung Lee (Committee Member); Jay Martin (Committee Member) Subjects: Ecology; Environmental Engineering; Environmental Management; Hydrology; Microbiology; Water Resource Management

Doctor of Philosophy, The Ohio State University, 2023, Food, Agricultural and Biological Engineering

Urban populations continue to increase with concurrent social and economic development often occurring at the expense of natural resources. Urban areas are characterized by a high density of impervious surfaces (i.e., roads, buildings, etc.) which are central to modern economies but disrupt many functions of the natural ecosystem by limiting stormwater infiltration, increasing habitat fragmentation, and absorbing a higher percentage of solar radiation. A growing number of communities are turning to green infrastructure (GI) to alleviate these stresses by increasing infiltration, evapotranspiration, and storage of stormwater. Commonly installed GI features include bioretention cells (BRCs), green roofs, and permeable pavement (PP). Bioretention cells are depressional retention facilities planted with native plants which infiltrate and filter stormwater using an engineered sandy media. Green roofs are alternatives to traditional roofs made up of layers of constructed membranes, substrates, and vegetation. Permeable pavements are alternatives to asphalt or concrete pavements that allow infiltration of stormwater through the pavement to the substrate below. Recent studies have focused on co-benefits of and ecosystem services provided by GI, including habitat creation, temperature mitigation, and community aesthetics. This dissertation was focused on GI efficacy in both natural and built systems. Broadly, this dissertation can be separated into two sections: 1) performance of BRCs in relation to hydrology and water quality (Ch. 1 and 2), and 2) performance and interactions of GI SCMs within human built systems (Ch. 3 and 4). Simulated runoff testing was conducted on a variety of BRCs to determine the hydrological and water quality performance as a function of their design (Ch. 1). In chapter 2, BRCs were tested for their ability to contain and remove Bacillus anthracis from simulated spore contaminated stormwater. Higher fines contents in the engineered media created (open full item for complete abstract)

Committee: Ryan Winston (Advisor); Scott Shearer (Committee Member); Ann Christy (Committee Member); Jay Martin (Committee Member) Subjects: Civil Engineering; Ecology; Environmental Engineering; Urban Planning; Water Resource Management

Doctor of Philosophy, The Ohio State University, 2020, Food, Agricultural and Biological Engineering

There is an urgent need to increase the habitat value of cities, both for human health and for conservation. Constructed Green Infrastructure (GI), which uses vegetated areas to solve engineering problems such as stormwater mitigation, is an attractive option for habitat creation, and ecological engineers, with their stated goal to design for both human and natural benefit, should be key players in its design and implementation. However, ecological engineers are hampered by the lack of a suitable reference by which to evaluate the ecological goals of the GI which they design. They are further hampered by the lack of information about the ecology of many common GI practices. Bioretention cells (BRCs) are the most common form of green infrastructure used for stormwater management. Much work has been done to evaluate the hydrological and pollutant-removal capabilities of BRCs, but there has been comparatively little investigation of the ecological properties of these systems. This is a critical gap in knowledge, as ecological design of BRCs could not only increase their functioning as stormwater infrastructure but could also contribute ecological value to urban areas. Investigation of the habitat value of BRCs could lead to design techniques that subsidize and/or prioritize habitat creation in tandem with stormwater management, allowing ecological engineers to capitalize on the current popularity of this practice to improve urban habitat for both humans and non-humans. I address this gap in knowledge with a multi-taxon survey of biodiversity in BRCs installed as part of a large-scale retrofit of GI in Columbus, OH. I developed and validated a protocol to survey birds with automated acoustic monitoring – a first in an urban area – and determined that BRCs affected bird community composition during spring migration but not during the summer breeding period. BRCs did not generally harbor more species than lawns, but nearby remnant ravines appeared to increase species (open full item for complete abstract)

Committee: Jay Martin PhD, PE (Advisor); Mary Gardiner PhD (Committee Member); Stephen Matthews PhD (Committee Member); Ryan Winston PhD, PE (Committee Member) Subjects: Ecology; Environmental Engineering

Master of Science, The Ohio State University, 2020, Food, Agricultural and Biological Engineering

As urban populations continue to increase, new impervious surfaces are constructed that inhibit stormwater infiltration and increase stormwater runoff. Rainfall characteristics such as peak intensity and antecedent dry period also influence the stormwater quantity and quality generated by urban landscapes. Green infrastructure (GI) offers an alternative to traditional urban drainage through stormwater control measures (SCMs) which improve water quality in addition to reducing runoff volumes. The City of Columbus has implemented a multi-pronged sanitary sewer overflow mitigation project (Blueprint Columbus) that included retrofitting GI practices into existing neighborhoods. This presented a unique opportunity to examine the impacts of GI retrofits on sewersheds >10 hectares in size, to build upon the many previous studies which evaluated single SCMs or multiple SCMs treating a relatively small catchment (<5 ha). Two studies were performed: (1) a paired watershed analysis to compare hydrologic indicators at the sewershed-scale pre- and post-GI retrofit, and (2) an analysis of rainfall characteristics which impact runoff hydrology and water quality, and how these factors change following the implementation of sewershed-scale GI. To investigate the sewershed-scale hydrologic impacts imparted by GI SCMs, monitoring of rainfall and stormwater flow in sewershed outfalls began in four sewersheds in 2016. Three sewersheds were retrofitted with GI SCMs while one served as the control with negligible GI implementation. Linear regressions and analysis of covariance were utilized in a paired watershed approach to compare pre-GI and post-GI data. Decreases in peak flow rates (40-58%) and increases in lag-to-peak (6-64%) were observed in the treatment sewersheds post-GI. Decreases in stormwater volumes were initially observed in GI sewersheds. Installation of additional stormwater infrastructure improvement projects (i.e. downspout disconnections, sanitary sewer late (open full item for complete abstract)

Committee: Ryan Winston Ph.D. (Advisor); Jay Martin Ph.D. (Advisor); Gil Bohrer Ph.D. (Committee Member) Subjects: Civil Engineering; Environmental Engineering; Hydrology; Water Resource Management

Doctor of Philosophy, The Ohio State University, 2019, Food, Agricultural and Biological Engineering

Bioretention is an increasingly prevalent green infrastructure practice for urban and suburban stormwater management. While research has shown the ability of this technology to reduce stormwater volume and improve stormwater quality, there is a gap in knowledge regarding long term performance. Additionally, hydrocarbons are an important but understudied stormwater pollutant. Column studies indicate bioretention is an effective treatment technology for reducing hydrocarbons in stormwater flows, but there is limited research confirming this performance in field settings. To address both of these concerns, simultaneous studies were performed evaluating the hydrological performance and hydrocarbon removal of a bioretention cell six years post installation. Nine simulated storms (3.5 mm equivalent storm) were conducted, with eight of those sampled for hydrocarbon concentrations. Despite an apparent increase in preferential flow as indicated by rapid bromide tracer breakthrough and accelerated water table response rates, there was no significant difference in volume reduction between 2011 (average 53%) measurements and those done in this study (2015-2016: average 69%), after accounting for runoff volume differences. These results indicate continued effective operation of this facility, at least during small events. The effective operation was possibly due to location (suburban neighborhood) and maintenance (~monthly sediment removal). Hydrocarbon mass reductions in bioretention tests (83%), measured as total petroleum hydrocarbons, were similar to other studies while concentration reductions were lower (53%), possibly due to low input concentrations (0.58 mg/L). Hydrocarbon concentrations in the soil were higher in the upslope cell, indicating historical accumulations. However, within each cell, concentrations did not vary significantly over the year of study, indicating steady state conditions iv and no accumulation during the period of study. Comparisons of hydrocarb (open full item for complete abstract)

Committee: Jay Martin PhD (Advisor); Winston Ryan PhD (Committee Member); Kalcic Margaret PhD (Committee Member); Gabor Rachel PhD (Committee Member) Subjects: Biogeochemistry; Environmental Engineering; Sustainability

MS, Kent State University, 2018, College of Arts and Sciences / Department of Earth Sciences

In urban areas, increased runoff from storm events is a significant concern due to flooding, erosion, ecosystem disturbance, and water quality problems. Phosphorus (P) and nitrogen (N) are key limiting nutrients that lead to eutrophication and harmful algal blooms in Lake Erie and other freshwater systems, and urban landscapes are locally important sources of nutrients to downstream water bodies. Green infrastructure (GI) is one increasingly popular solution being used in urban areas to address the water quantity and quality issues that urban runoff creates. Green roofs and bioretention cells are widely used forms of GI designed to decrease and slow down runoff through evapotranspiration and infiltration. I compared the hydrologic effectiveness of a co-located extensive green roof and two bioretention cells in northeastern Ohio, in order to understand their relative capacities to decrease and slow down stormwater runoff, when subjected to the same weather conditions. I also monitored the green roof to understand its effects on water quality, in terms of P and N. From June 2015 to November 2016, 93 storms from 2.5 to 62 mm, were monitored. To assess the hydrologic performance of each site, I measured rainfall, underdrained outflow, groundwater levels in the bioretention cells, and soil moisture on 1–5 minute intervals. To assess water quality for the green roof, I collected precipitation and samples from the green roof downspout. I measured chloride (Cl-) phosphate (PO43-), total P, nitrate (NO3-), ammonium (NH4+), and total N concentrations using ion chromatography and a colorimetric assay. The bioretention cells performed similarly to each other, despite slightly different designs, and they had superior performance to the green roof. The paved lot bioretention cell showed 77% volumetric and 85% peak flow reduction and the gravel lot bioretention cell showed 78% volumetric and 82% peak flow reduction. The green roof only reduced 59% of its water input and 69% (open full item for complete abstract)

Committee: Anne Jefferson (Advisor); Lauren Kinsman-Costello (Advisor); Elizabeth Herndon (Committee Member) Subjects: Ecology; Environmental Science; Geology; Hydrology; Sustainability; Water Resource Management

Master of Science (MS), Ohio University, 2018, Civil Engineering (Engineering and Technology)

Parking lots are a large contributor of undetained and untreated stormwater runoff in urban watersheds. Green infrastructure (GI) practices, such as bioretention cells (BRCs), can be implemented to offset the negative effects of parking lots. In this study, a BRC was designed to intercept the WQv from an existing asphalt parking lot before it entered nearby Goose Run in Marietta, Ohio. Construction errors limited the ponding storage volume of the BRC to only 18% of the design. Average infiltration rates ranged from 2.66 in/hr to 7.67 in/hr with an overall average rate of 5.24 in/hr. The ability of the undersized BRC to reduce runoff volumes, mitigate peak flows, reduce runoff temperature, and remove TSS from the parking lot runoff before it discharged to Goose Run was investigated. The BRC reduced runoff volumes by 51.1% and 76.4%, reduced peak flows by 66.4% and 81.5% and lagged peak flows by 1.01 hr to 1.58 hr. These conclusion were drawn from inflow and outflow data that were adjusted due to limitations in the monitoring methods and therefore contain some uncertainty. The BRC reduced parking lot runoff temperatures by 3°C. The BRC reduced event average TSS concentrations by 92.1% to 98.7% and EMCs by 93.4% to 97.3%. Effluent TSS concentrations were lowered once a capped orifice design was implemented to control the flows from the underdrain outlet, but further research is still needed.

Committee: Guy Riefler (Advisor); Tiao Chang (Committee Member) Subjects: Civil Engineering

Master of Science, University of Toledo, 2015, Civil Engineering

Increases in impervious surface, a direct result of urbanization, have resulted in the impairment of the natural water cycle. The transition from pervious vegetated cover to impervious pavement and building cover results in greater surface runoff generation and decreased groundwater recharge. The increase in runoff volumes results in greater pollutant delivery to receiving streams and disrupts the natural stream hydrology. The frequency of high intensity precipitation events is increasing due to global climate change, exacerbating the effects of urban runoff on the water system. The water quantity and quality impairments associated with urban stormwater runoff can be mitigated using bioretention LID controls. The overarching objective of this project was to assist in the development of a cohesive and coordinated plan for implementation of green stormwater strategies in Toledo - Lucas County. In this study, a combination of SWMM5 modeling and GIS analyses were used to identify candidate properties for bioretention, in three urban land use types, throughout Lucas County, Ohio. The GIS analysis using soil, land-use and parcel data identified 7,159 bioretention candidate parcels in vacant residential, multi-family residential and commercial properties. SWMM5 modeling results applied to the identified parcels estimated a potential total volume reduction of over four billion liters per year, generated over 1140 treated urban hectares. The results of the study support current bioretention design standards and note the benefit of the utilization of bioretention in some Hydrologic Soil Group D soils. This work supports future studies utilizing similar methodology to plan and prioritize LID control implementation and to estimate large scale pollutant removal performance.

Committee: Cyndee Gruden Dr. (Advisor); Defne Apul Dr. (Committee Member); Richard Becker Dr. (Committee Member) Subjects: Civil Engineering; Engineering; Environmental Engineering; Geography; Water Resource Management

Master of Science, The Ohio State University, 2012, Food, Agricultural and Biological Engineering

During June-September 2011, simulated rain events were conducted by flooding one 3-cell rain garden with water spiked at various nutrient concentrations: total nitrogen (TN) range= 0.49 ppm to 3.68 ppm; total phosphorus (TP) range = 0.25 to 0.61 ppm. This series of controlled inundations was conducted to simulate eight 12.7-mm rain events. Water samples were collected at 10-minute intervals from water entering the garden, discharging through underdrains and at three depths in the garden , then analyzed for: TN, nitrate + nitrite (NO3 + NO2), ammonia (NH3), TP and orthophosphate (PO4) to monitor nutrient concentration over a time period of two hours. Hydrologic data were collected simultaneously to monitor inflow and discharge volumes, and pressure transducers recorded the water level in the garden. The study examined N and P concentrations and masses as they moved though the soil profile. Data averaged across all input spike levels indicate that overall, the garden reduced nutrient loads: 38% reduction in NH3, 20% reduction in TN, 46% reduction in PO4 and TP, and 44% reduction of organic-P. These findings suggest that undersized gardens can contribute to water quality improvement efforts despite their small area to watershed ratio (2.13%). Nitrification transformation was suspected to occur at 30-60cm depths in the zone with the greatest water content fluctuation. The observations identified the importance of the upper layers of the garden in P removal and the lower layers in N transformation.

Committee: Jay Martin PhD (Advisor); Ward Andrew PhD (Committee Member); Witter Jon PhD (Committee Member); Naber Steven PhD (Committee Member); Jepsen Dee PhD (Committee Member) Subjects: Civil Engineering; Environmental Engineering; Environmental Science; Hydrology; Urban Planning; Water Resource Management

Master of Science, The Ohio State University, 2012, Food, Agricultural and Biological Engineering

Increased storm runoff results from urbanization and development. Rain gardens can reduce runoff in a cost-effective manner as compared to expensive infrastructure construction, but more knowledge of their behavior and performance are required to increase their applications. This research demonstrates that rain gardens can reduce storm runoff from developments built without stormwater retention infrastructure to mitigate increases in storm runoff. Retrofit rain gardens were installed in a residential neighborhood in Westerville, Ohio, in July 2010. Between spring of 2011 and 2012, inflow and outflow volumes and soil water content were monitored for 20 simulated rainfall events. The change in water storage within the rain garden was calculated from the initial and final soil water content of 15 cm layers for the 60 cm depth of the rain gardens. A water balance equation was used to estimate the volume of water exfiltrating to the surrounding in situ soil. Overall, the rain gardens provided a 44% volume reduction from inflow to outflow with 15% of the inflow exfiltrating to the surrounding soil. Three inlet designs for right-of-way rain gardens were also evaluated. The original construction allowed for vegetative growth at the inlet, which accumulated debris and inhibited inflow during natural storm events. Replacing the vegetation and soil at the entrance with stones reduced hydrologic performance, but underlining the stones with bentonite clay provided a statistically significant increase in volume reduction during simulated rainfall events. This study finds that retrofit, right-of-way rain gardens can substantially reduce storm runoff in a residential development despite their proximity to curb underdrains and their small garden to impervious area ratios.

Committee: Jay Martin PhD (Advisor); Andrew Ward PhD (Committee Member); Larry Brown PhD (Committee Member) Subjects: Agricultural Engineering; Civil Engineering; Ecology; Engineering; Environmental Engineering; Hydrology

Doctor of Philosophy, The Ohio State University, 2010, Environmental Science

Rain gardens are bioretention systems that have the potential to reduce peak runoff flow and improve water quality in a natural and aesthetically pleasing manner. In spite of their popularity, results from column and field-scale studies show that level of pollutant removal in rain gardens varies and is not always positive. To date, research has often focused on a limited number of runoff pollutants. This study was conducted to develop and evaluate a new rain garden design for flow management and pollutant removal from stormwater runoff. Both column and field-scale biphasic rain gardens were designed and constructed to increase retention time and maximize removal efficiency of multiple runoff pollutants by creating a sequence of anaerobic to aerobic conditions. To evaluate hydraulic performance and pollutant removal capacity of the biphasic rain gardens, studies were conducted under actual and simulated runoff conditions with spiked concentrations of nutrients (nitrate-N and phosphate-P), and herbicides (i.e. atrazine (6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine), glyphosate (N-(phosphonomethyl)glycine), dicamba (3,6-dichloro-2-methoxybenzoic acid), and 2,4-D (2,4-dichlorophenoxyacetic acid)). Both column and field-scale studies showed that the biphasic rain gardens have the potential to be an effective best management practice for reducing stormwater flow and pollutant loads. Peak flow and runoff volume were effectively reduced five-fold in the biphasic rain gardens for actual and simulated runoff events by holding runoff in the rain gardens (mainly in the anaerobic zone) until a subsequent runoff event. The field-scale biphasic rain gardens were highly effective in removing nitrate-N (~91%), phosphate-P (~99%), atrazine (~90%), dicamba (~92%), glyphosate (~99%), and 2,4-D (~90%) under high levels of pollution loading conditions simulated in both agricultural and urban runoff events. The column studies demonstrated that the biphasic rain garden, c (open full item for complete abstract)

Committee: Warren A. Dick PhD (Advisor); Parwinder S. Grewal PhD (Advisor); John Cardina PhD (Committee Member); Edward L. McCoy PhD (Committee Member) Subjects: Environmental Science

Master of Science, The Ohio State University, 2009, Soil Science

A field-scale, bi-phasic rain garden (three replicates) was constructed to evaluate the growth of six plant species native to Ohio and the effectiveness of the rain garden to remediate heavy metals (Cu, Cr, Pb and Zn) from simulated stormwater runoff. The first phase, an anaerobic, oxygen-poor zone contained Eupatorium perfoliatum (boneset), Tradescantia ohiensis (spiderwort) and Veronicastrum virginicum (culver's root). In the second, aerobic, oxygen-rich zone Sorghastrum nutans (Indian grass), Echinacea purpurea (purple coneflower) and Eragrostis spectabilis (purple lovegrass) were grown. The plants, 234 overall, were evaluated over six months in 2008 and four months in 2009 with regards to height, width, number of flowers and general observations. Heavy metal remediation was evaluated over three simulated storm events that were carried out over an 11-day period with each rain event five days apart. During the first two storms, heavy metal pollutants were applied and the effluent water was measured on the eleventh day. On a mass balance basis, there was greater than 99% removal efficiency for Cu, Cr and Pb. In one replication, there was only a 72% removal of Zn, whereas the removal efficiency for the other two replications was greater than 99%. Most of the plants established well. The grasses S. nutans and E. spectabilis established slowest and E. perfoliatum and E. purpurea established the fastest. After the first year, 91% of the total plants survived and re-grew in the second year. V. virginicum had the poorest survival with nearly a quarter of the plants not growing in the second year, the highest of any species. The suitability of this species and E. perfoliatum, with its leaves having been eaten by insects, is questionable in this bi-phasic rain garden. The other species were suitable under the tested conditions. Careful selection of plants, including those native to Ohio, resulted in plants that grew well in the bi-phasic rain garden and provided both effec (open full item for complete abstract)

Committee: Warren Dick PhD (Advisor); Parwinder Grewal PhD (Committee Member); Edward McCoy PhD (Committee Member) Subjects: Environmental Engineering; Environmental Science; Soil Sciences