Urbanization causes various environmental issues including water pollution, air pollution, and solid waste. Urbanization of watersheds has a profound influence on the quality of stormwater runoff. The quality of stormwater runoff is highly associated with land use. This study analyzed the exceedance frequency of stormwater quality in five watersheds of Denton over eleven years and also analyzed the relationship between stormwater quality and land use/cover of each watershed. The results showed that the most of the water quality parameters that were examined in the Lower Pecan watershed exceeded their threshold most frequently. The higher frequency of exceedance in this watershed can be attributed to the wastewater treatment plant and landfill site. Total suspended solids and turbidity were frequently exceeded in Hickory and Clear Creek watersheds. Conductivity was found to have highest percentage of exceedance in Upper Pecan and Cooper watersheds. Thus, rural watersheds were related with higher exceedance of TSS and turbidity whereas urban watersheds were related with higher exceedance of conductivity.

Rain gardens are low impact developments designed to mitigate a suite of issues associated with urban stormwater runoff. The site for this study was a Denton City rain garden at the Denton Waste Water Treatment Plant. Nitrogen and phosphorus removal was examined in light of two overflow events comprised of partially treated wastewater from an upslope anaerobic digester pond. Nitrate removal efficiency was examined across differing dry spell intervals of 5, 8, and 12 d, displaying a moderate negative correlation (r2 = 0.59). Continued phosphorus removal capacity was assessed, showing phosphorus removal in cases where P was in excess of 0.8 mg/L, reflecting an equilibrium phosphorus concentration. A high expanded shale component in the soil media (25%) was likely a factor in the continued removal of phosphorus. Overall the rain garden proved to be a large source of nitrate (+425%) and total nitrogen (+61%) by mass. The study showed that while the rain garden intercepted a large volume of partially treated wastewater during the overflow events, preventing it from reaching a nearby creek, the mitigation of an acute event has extended to a chronic one as nitrogen is gradually processed and flushed from the system as nitrate.

Urbanization has posed great challenges for environmental sustainability, human health, and wellbeing. One of these challenges is stormwater management stemming from widespread imperviousness in urban areas. For many cities, including New York City, stormwater management issues are being exacerbated by the impacts of climate change, which is increasing the frequency and intensity of wet weather flows in multiple regions of the world. In New York City, stormwater runoff is collected with wastewater sewage in a combined sewer system (CSS) that dates back to over a century ago. At the time the system was put in place, it was designed to transport a combination of storm and wastewater to local treatment plants with a capacity of about twice the dry-weather flow. With the expansion of urbanization and population growth, this outdated system is now easily overwhelmed during wet weather flow. In some areas of the City, rainfall of less than a few millimeters can cause untreated combined storm and waste water in excess of the system’s capacity (Schlanger, 2014), to be discharged directly into a nearby surface water. The combination of storm and wastewater is referred to as combined sewerage, and overflow events are referred to as combined sewer overflows (CSOs). CSOs are a leading source of local water body pollution in NYC, as well as countless other older cities in the US and abroad that operate with combined sewer systems. To solve the CSO problem, many cities, including NYC, have adopted green infrastructure (GI) plans that aim to capture stormwater locally before it can make its way into a CSS. In New York City, right-of-way bioswales (ROWBs) are composed of about 60% of the GI that has been implemented to date (The New York City Department of Environmental Protection, 2020) for stormwater management and CSO reduction. However, despite the popularity of ROWBs as a GI intervention, few research studies have focused on quantifying their hydrological performance. This can be attributed, in part, to the greater complexity of ROWB behavior in comparison to other GI interventions, such as green roofs, which have attracted wider research interest. In addition, because ROWBs are located in the public right-of-way, monitoring and measurement of the behavior of these systems also poses additional challenges. The first study in this dissertation presents three new field methods for quantifying the stormwater retention capacity of individual ROWBs. By applying the field methods at a ROWB site located in the Bronx, NYC, the influence of rainfall characteristics and the monitored soil moisture content of the ROWB on the ROWB’s hydrological performance was explored. A definition of a so-called ‘rain peaky event’ (RPE) was introduced to divide an individual storm into several sub-events. A RPE event-based empirical model for predicting the stormwater retention behavior of the ROWB was then developed based on the monitored soil moisture content of the ROWB and the rain depth recorded every 15 minutes during a storm event. This study found that the predicted stormwater retention volume per rain depth per unit drainage area of the studied ROWB, is not significantly different from that of several NYC based extensive green roofs. However, compared to the drainage area of the green roofs, which is the same as the roof’s surface area, the drainage area of the studied ROWB was about 84 times its surface area. Thus, per unit area, the ROWB was found to have significantly higher (almost two orders of magnitude) total stormwater capacity than the extensive green roofs. The second study in this dissertation assessed the applicability of the physics-based one-dimensional finite element model HYDRUS-1D, for simulating the infiltration process of a ROWB during storm events using long-term monitored soil moisture content as an input. The simulation results from the HYDRUS-1D was validated by field measurement results taken at the ROWB site located in the Bronx, NYC, and compared with the RPE event-based empirical model presented in the first study. The HYDRUS-1D model was found capable of predicting the ROWB’s cumulative stormwater retention at intervals of one minute, as well as the total retention volume of stormwater inflows into the ROWB per rain peaky event, except for events with an average stormwater inflow intensity high than 20 cm/hr. The study revealed that HYDRUS-1D has a tendency to under-predict the retention capacity of the studied ROWB for a storm with an inflow intensity high than 20 cm/hr, thus providing a lower bound on ROWB stormwater retention. The current published version of the HYDRUS-1D was also found to be erroneous when simulating the ROWB stormwater infiltration process in cases where the ROWB’s soil moisture content was close to saturation. The third study investigated the effectiveness of increased perviousness on CSO reduction and water quality improvement in NYC, toward an aim of understanding how GI implementation can improve city-wide stormwater management issues. By using the enterococci (ENT) concentration as an indicator of water quality and the runoff coefficient to represent land perviousness over an area, a random forest classification model was developed for predicting whether a water body is swimmable or not at 50 shore sites along the main waterways of NYC. The model revealed the significant contribution of land perviousness, and hence GI interventions and green space, to CSO pollution reduction for CSO-shed areas located adjacent to slower-moving waterways. For CSO-shed areas located adjacent to faster moving waterways, the influence of land perviousness was found to be negligible. The random forest classification model developed in this third study can be used as a tool for city planners and agencies as part of plans for GI implementation that focus on the optimization of local water quality, among other objectives. Overall, the research presented in this dissertation aimed to provide a deeper insight into the factors governing the hydrological performance of the most prevalent GI in NYC – namely right-of-way bioswales. In addition, the research aimed to provide insight into linkages between land perviousness and CSO pollution levels in NYC local waterways, which can be used to inform the implementation and overall performance of the entire NYC GI system.

Urbanization, often characterized by high impervious surface area, can result in excessive inputs of fine sediments into urban streams. Excessive fine sediments can blanket the stream bed filling the interstitial space in the substratum, which may have adverse effects on stream biota. A field survey was conducted in Oregon urban and non-urban basins to investigate the relationship between fine sediments and stream macroinvertebrates. Physical, chemical, and biological data were collected from 59 stream sites in two urban and two rural streams. The stream sites fulfilled a continuous sediment gradient, which ranged from a low of 2% of fine sediment in the substrate to a high of 64% with an average of 22%. The % fines, in Clear Creek (rural basin) was significantly lower than in the urban basins (Johnson Creek and Tryon Creek) (p=0.005). Johnson Creek (mean=23%) had approximately three times more fine sediment than Clear Creek (mean=7%), while Tryon Creek (mean=32%) had nearly five times as much fine sediment as Clear Creek. EPT taxa richness was significantly higher in both rural streams than in both urban streams (p0.05). For example, regression analysis of EPT taxa richness vs. % fine sediments displayed a coefficient of determination (r2) value of 0.2. Other macro invertebrates metrics displayed similar patterns. The lack of significant correlations may be due to the cumulative effect of basin-wide "historical land use past". Past land use activity may have resulted in long-term reductions of sensitive taxa in the basin taxa pool and efforts to improve local habitats may not be quickly colonized by pollution sensitive taxa. Long-term degradation to the urban streams resulted in a relatively homogenous assemblage of macro invertebrates, which may have confounded the quantitative relationship between sediments and macroinvertebrates. This study suggests there is a clear difference between urban and non-urban streams in terms of macro invertebrates, which may be likely due to sediments, but the quantitative relationship between fine sediments and macro invertebrates is weak.

The Stephens Creek Watershed in southwest Portland, Oregon was chosen by the city as a pilot project for urban stream restoration efforts, and the infiltration of stormwater was identified as a potential restoration strategy. The Stephens Creek Watershed has historically been known to be unstable during high precipitation events (Burns, 1996), and the need to address the response of slope stability to anthropogenically-driven changing groundwater conditions is the focus of this study. Airborne light detection and ranging (LiDAR) and geotechnical data from the City of Portland were employed to create a high resolution (0.84 m2) physics-based probabilistic slope stability model for this watershed, using the map-based probabilistic infinite slope analysis program PISA-m (Haneberg, 2007). Best and worst case models were run using fully dry and fully saturated soil conditions, respectively. Model results indicate that 96.3% of the watershed area had a probability [less than or equal to] 0.25 that the slope factor of safety (FOS) was [less than or equal to] 1 for fully dry conditions, compared to 76.4% for fully saturated conditions. Areas that had a probability [greater than or equal to] 0.25 that the slope factor of safety (FOS) was [less than or equal to] 1 were found to occur mainly along cut/fill slopes as well as within the deeply incised canyons of Stephens Creek and its tributaries. An infiltration avoidance map was derived to define areas that appear to be unsuitable for infiltration. Based on these results, it is recommended that stormwater continues to be directed to existing sewer infrastructure and that the "storm water disconnect" restoration approach not be used by the city.

The purpose of this study was (1) to study the proportion (X) of the flow in a watercourse that consists of urban runoff during a rain event and (2) to evaluate the risk that a few chosen pollutants, transported by urban runoff, exceed the maximum allowed concentration in the watercourse according to the environmental quality standards (MAC-EQS). The Fyris river in Uppsala, Sweden, was selected as a case study. Urban runoff quickflow was estimated with a water balance model using precipitation data and flow data from three stations. Precipitation data was used to identify 31 rain events with a minimum rain volume of 10 mm and at least a maximum rain intensity of three mm/h during the study period 2017-2020. Pollutants in urban runoff were sampled during the winter of 2020-2021. The highest concentrations obtained during sampling were used to estimate momentary pollution concentration and to evaluate the risk of exceeding MAC-EQS. The highest X found during a rain event was 71%. Low flow conditions in the river prior to a rain event in summertime are circumstances when X can be expected to be high. It is therefore advised to include rain events under such circumstances when monitoring MAC-EQS or sampling momentary pollution concentrations in the Fyris river. The pollutant category polycyclic aromatic hydrocarbons (PAH), and especially the pollutant fluoranthene, showed risk of momentary pollution concentration exceeding MAC-EQS. Therefore, the author recommends that future studies of urban runoff should include PAHs. / Syftet med denna studie var (1) att studera hur stor andel (X) av flödet i ett vattendrag som utgörs av dagvatten vid ett regntillfälle, och (2) att utvärdera risken att ett utvalt antal föroreningar som transporteras med dagvattnet överskrider maximal tillåten koncentration enligt miljökvalitetsnormerna för vatten (MAC-MKN). Fyrisån i Uppsala, Sverige, valdes som fallstudie. Snabbt dagvattenflöde (quickflow) uppskattades med en vattenbalansmodell som använde nederbördsdata samt vattenföring från tre stationer. Nederbördsdata användes för att identifiera 31 regntillfällen med en minsta regnvolym på 10 mm och minst en maximal regnintensitet på tre mm/h under perioden 2017-2020. Föroreningar i dagvatten provtogs under vintern 2020-2021. De högsta koncentrationerna som påträffades vid provtagningen användes för att uppskatta momentan föroreningskoncentration och för att utvärdera risken att MAC-MKN överskrids. Det högsta X som beräknades under ett regntillfälle var 71%. Lågt flöde i Fyrisån innan ett regntillfälle under sommartid är omständigheter när X kan förväntas vara högt. Det rekommenderas därför att inkludera regntillfällen under sådana omständigheter när MAC-MKN övervakas eller när momentana föroreningskoncentrationer i Fyrisån provtas. Föroreningskategorin polycykliska aromatiska kolväten (PAH), och särskilt föroreningen fluoranten, uppvisade risker för att MAC-MKN skulle överskridas. Därför rekommenderas att framtida studier av dagvatten bör inkludera PAH:er.

The subject of water scarcity and the rate of water consumption has become popular topics over the last few decades. It is possible that society may consume or contaminate much of the remaining readily available water if there is not a paradigm shift. This deep rooted concern has prompted investigations to identify alternative water use and treatment methods. Within this report, information is presented from the use of innovative water harvesting and on-site sewage treatment and disposal systems (OSTDS) at Florida’s Showcase Green Envirohome (FSGE.net), while also addressing low impact development (LID) practices. FSGE is a residential home that demonstrates methods that use less water and reduce pollution. Population increases have more than just an effect on the volume of water demanded. Adverse impacts on surface and groundwater quality are partially attributed to current design and operation of OSTDS. Nutrient loading from wastewater treatment systems may be a concern where numerous OSTDS are located within nutrient sensitive environments. Groundwater nitrate concentrations have been shown to exceed drinking water standards by factors of three or greater surrounding soil adsorption systems (Postma et al., 1992, Katz, 2010). As a contribution to efforts to reduce water use and improve water quality, this study investigates the viability and effectiveness of a residential integrated stormwater, graywater, and wastewater treatment system (ISGWTS) installed and operating for over a year at FSGE. ii Within this report is a continuation of results published previously that consisted of preCertificate of Occupancy (pre-CO) data and an optimization model at the Florida’s Showcase Green Envirohome (FSGE) in Indialantic, Florida (Rivera, 2010). This current report contains 12 months of post-CO data, along with data from bench scale models of the on-site septic treatment and disposal system (OSTDS). There are two main objectives of the study. The first objective is to quantify the performance of the passive treatment Bold & GoldTM reactive filter bed (FDOH classified “innovative system”) for nutrient removal. The second objective was to monitor the water quality of the combined graywater/stormwater cistern for non-potable use and assess the components (green roof, gutters, graywater piping). The performance of the passive innovative system is compared to past studies. Also a bench scale model that is constructed at the University of Central Florida (UCF) Stormwater Management Academy Research and Testing Lab (SMART Lab) is operated to provide data for two different retention times. Complex physical, biological, and chemical theories are applied to the analysis of wastewater treatment performance. The data from the OSTDS and stormwater/graywater cistern are assessed using statistical methods. The results of the OSTDS are compared to FDOH regulatory requirements for “Secondary Treatment Standards”, and “Advanced Secondary Treatment Standards” with promising results. The bench scale results verify that both nitrogen and phosphorus removal are occurring within the filter media and most likely the removals are due to iii biological activity as well as physiochemical sorption. The flow into the OSTDS has been reduced with the use of separate gray water system to only 29 gallons per person per day (gpcd). After the FSGE certificate of occupancy and for one year using the Bold & Gold Biosorption Activated Media (BAM), the TSS, BOD5, and CBOD5 are below the required 10 mg/L for the FDOH classified Advanced Secondary Treatment Systems. The effluent for the conventional drain field TSS, BOD5, and CBOD5 are above 10 mg/L (29.6, 35.7, and 29.0 mg/L). The effluent total nitrogen and total phosphorus for the innovative system are 29.7 mg/L and 4.1 mg/L, which are not low enough for the 20 mg/L nitrogen requirements, but are below the 10 mg/L phosphorus requirements. The conventional drain field has an effluent total nitrogen concentration of 70.1 mg/L and an effluent total phosphorus concentration of 10.6 mg/L, which both fail to meet FDOH Advanced Secondary Treatment requirements. The high nitrogen in the effluent can be attributed to high influent concentrations (about 3 times the average at about 150 mg/L). Longer residence times are shown to produce a removal greater than 90%. Also, nitrate average levels were below the 10 mg/L standard. The combined stormwater/graywater cistern is analyzed against irrigation standards. The graywater is filtered and disinfected with ozone to provide safe water for reuse. Nutrient concentrations are measured to compare with regulatory standards. For irrigation standards, salinity in the form of sodium, calcium, and magnesium are measured. Although high sodium adsorption ratio (SAR) and electrical conductivity (EC) values were recorded, their adverse iv impact on the vegetation has not been observed. . The only observed effect within the home to date is scale formation in the toilet. The use of potable water in FSGE is reduced to 41 gpcd using the integrated stormwater and graywater system. A minor volume of backup artesian well water was added to the cistern during the one year home occupancy phase. Based on less use of potable water and at the current potable water cost rate, the integrated stormwater and graywater system at FSGE will save the typical homeowner about $215 per year. If irrigation were used more often from the cistern, the cost savings in reduced potable water used for irrigation would increase the savings. The treatment cost for B&G BAM over a 40 year period of time based on a flow of 29 gpcd (as measured at FSGE) and for 4 persons is $2.07 per thousand gallons treated. The yearly cost of treatment is about $87.65. There is a reduction in potable water use estimated at 64% of the sewage flow (or 18.5 gpcd) which equates to about 27 thousand gallons in one year. The current average cost of potable water is $4.40 per thousand gallons. Based on reduced potable water usage, the savings per year are about $118.84. Thus the yearly savings in potable water cost ($118.84) offsets the cost of OSTDS treatment at FSGE for nutrient control ($87.65) using the data collected at FSGE. This comparison does not include the inflation cost of water over time. There is also an environmental preservation intangible cost (not quantifiable from this study) from reduced surface runoff and reduced pollutant discharges.

Urban stormwater runoff is both an environmental threat and a valuable water resource. This dissertation explores the use of two stormwater management strategies, namely green stormwater infrastructure and stormwater real-time control (RTC), for capturing and treating urban stormwater runoff. Chapter 2 focuses on clean bed filtration theory and its application to fecal indicator bacteria removal in experimental laboratory-scale biofilters. This analysis is a significant step forward in our understanding of how physicochemical theories can be melded with hydrology, engineering design, and ecology to improve the water quality benefits of green infrastructure. Chapter 3 focuses on the novel application of unsteady transit time distribution (TTD) theory to solute transport in a field-scale biofilter. TTD theory closely reproduces experimental bromide breakthrough concentrations, provided that lateral exchange with the surrounding soil is accounted for. TTD theory also provides insight into how changing distributions of water age in biofilter storage and outflow affect key stormwater management endpoints, such as biofilter pollutant treatment credit. Chapter 4 focuses on stormwater RTC and its potential for improving runoff capture and water supply in areas with Mediterranean climates. We find that the addition of RTC increases the percent of runoff captured, but does not increase the percent of water demand satisfied. Our results suggest that stormwater RTC systems need to be implemented in conjunction with context-specific solutions (such as spreading basins for groundwater recharge) to reliably augment urban water supply in areas with uneven precipitation. Through a combination of modeling and experimental studies at a range of scales, this dissertation lays the foundation for future integration of TTD theory with RTC to improve regional stormwater management. / Doctor of Philosophy / Urban stormwater runoff contains a variety of pollutants. Conventional storm drain systems are designed to move stormwater as quickly as possible away from cities, delivering polluted runoff to local streams, rivers, and the coastal ocean – and discarding a valuable freshwater resource. By contrast, green stormwater infrastructure captures and retains stormwater as close as possible to where the rain falls. Green stormwater infrastructure can also help remove pollutants from stormwater through physical, chemical, and biological treatment processes. This dissertation describes two modeling approaches for understanding and predicting pollutant removal processes in green stormwater infrastructure (Chapters 2 and 3). Chapter 4 explores the implementation of smart stormwater systems, which use automated controllers and sensors to adaptively address stormwater management challenges. Through a combination of modeling and experimental studies at a range of scales, this dissertation lays the foundation for future improvements to regional stormwater management.

Cities are home to more than half of the world’s population, and this figure is set to continue to rise amidst ongoing global urbanization trends. Against this backdrop, urban development is increasingly confronted with multifaceted challenges. These range from public health emergencies, exemplified by the COVID-19 global pandemic, to the environmental hazards driven by climate change, including extreme heat waves and more frequent severe storms. Confronted with these substantial risks, the urgency of devising and implementing strategies for sustainable and resilient urban development has become paramount. Given this context, the work presented in this thesis aims to advance understanding of some critical urban sustainability challenges, and to develop models, tools, and sensing systems that can support progress towards a more sustainable and resilient urban future. The first part of the thesis focuses on the role and usage of urban parks during a global public health emergency. Urban parks became critical for maintaining the well-being of urban residents during the COVID-19 global pandemic. To examine the impact of COVID-19 on urban park usage, New York City (NYC) was selected as a case study, and SafeGraph mobility data, which was collected from a large sample of mobile phone users, was used to assess the change in park visits and travel distance to a park based on park type, the income level of the visitor’s census block group (visitor CBG) and that of the park census block group (park CBG). All analyses were adjusted for the impact of temperature on park visitation, and the research work was focused primarily on park visits made by NYC residents. Overall, for the eight most popular park types in NYC, namely – Community Park, Flagship Park, Jointly Operated Playground, Nature Area, Neighborhood Park, Playground, Recreation Field/Courts and Triangle/Plaza – visits dropped by 49.2% from 2019 to 2020. The peak reduction in visits occurred in April 2020. Visits to all park types, excluding Nature Areas, decreased from March to December 2020 as compared to 2019. Parks located in higher-income CBGs tended to have lower reductions in visits, with this pattern being primarily driven by visits to large parks, including Flagship Parks, Community Parks and Nature Areas. All types of parks saw significant decreases in distance traveled to visit the park, with the exception of the Jointly Operated Playground, Playground, and Nature Area park types. Visitors originating from lower-income CBGs traveled shorter distances to parks and had less reduction in travel distances compared to those from higher-income CBGs. Furthermore, both before and during the pandemic, people tended to travel a greater distance to parks located in high-income CBGs compared to those in low-income CBGs. Finally, multiple types of parks proved crucial destinations for NYC residents during the pandemic. These included Nature Areas to which the visits remained stable, along with Recreation Field/Courts which had relatively small decreases in visits especially for lower-income communities. Results from this particular research study can support future park planning by shedding light on the different users of certain park types before and during a global crisis, where access to green spaces can help alleviate the human well-being consequences associated with mitigating the crisis, including the type of “lockdown” or limited mobility policies implemented in 2020 during the COVID-19 global pandemic. The second part of the thesis investigates the role of urban greening and other land surface features in influencing the urban heat island effect in NYC. The urban heat island (UHI) effect describes the phenomenon whereby cities are generally warmer than surrounding rural areas. UHI effects can exacerbate extreme heat events, leading to an increase in heat-related illness and mortality. Here, the runoff coefficient was used as a numerical surrogate for urban greening, with lower runoff coefficients being associated with higher fractions of urban greening. Using a high-resolution landcover GIS dataset developed for New York City (NYC), which classified the city into more than 13 million land patches, the runoff coefficient of land use across the entire city was mapped down to a resolution of 30m×30m, along with five other variables including surface albedo, distance to water bodies, land surface elevation, building density and building height. Daytime land surface temperature (LST) in summer was used as a surrogate for the UHI effect in NYC, and the work investigated the relationship between the runoff coefficient and LST. The work also examined the relationship between LST and the variables of surface albedo, distance to a water body, land surface elevation, building density and building height. Results indicate that runoff coefficient can explain a large portion of variability related to urban LST, with lower runoff coefficients (more greenery) being associated with lower LST. Use of the five other variables improves the predictability of LST, although the influence each variable has on LST varies with urban setting and context. The research work presented in this part of the thesis also shows the disproportionately higher exposure to urban heat in lower-income communities in NYC. The findings can be used to develop strategies to mitigate UHI effects in NYC and other cities around the world. In the third part of the thesis, a wireless environmental sensing system is developed for monitoring urban green spaces, with demonstrated application for stormwater management. The monitoring of urban green spaces, including monitoring of soil conditions and soil health, is crucial for sustainable urban development and ecological resilience. Leveraging advances in wireless environmental sensing, a LoRaWAN-based system capable of measuring air temperature/humidity, soil temperature and moisture, and soil moisture dynamics is designed and deployed across seven diverse urban green spaces for a full year at Columbia University’s Morningside Campus in New York City. The data collected by this sensing network reveals notable variations in soil moisture across the seven monitored sites, which are influenced by a combination of vegetation type, soil conditions, and physical settings. Monitored lawns consistently showed higher soil moisture levels due to their slower draining soil type, underlying concrete structures, and lower canopy rainfall interception and transpiration loss, whereas one monitored tree pit site with a more rapidly draining soil type showed significantly lower soil moisture throughout the study period, despite having comparable physical settings with another monitored site. Seasonal trends indicated lower summer moisture in some monitored areas due to increased evaporation and transpiration under high temperatures, while others areas maintained higher soil moisture as a result of frequent irrigations. Models were developed to quantify soil moisture response to rainfall events. It was found that the increase in soil moisture at each monitored site was highly dependent on the rainfall depth and the initial soil moisture. Overall, the results show that a range of diverse green spaces can help retain and drain storms up to certain sizes of 30-50mm. However, proactively designed soil drainage systems are needed to handle extreme storm events above 50mm. The study highlights the effectiveness of LoRaWAN technology in urban environmental monitoring and provides valuable insights into how different urban green spaces can contribute to stormwater management. The findings presented in this portion of the thesis demonstrate the instrumental role that monitoring, data analysis and modeling can play in helping city planners and environmental managers optimize urban green spaces for ecological benefits and enhance urban resilience, including in the face of stressors such as climate change. Overall, with its data-driven, evidence-based insights, this work contributes to the understanding of the multifaceted urban sustainability challenges in a changing environment, including public health emergencies such as the COVID-19 global pandemic, and climate change induced environmental hazards such as extreme heat events and more frequent severe storms. Alongside deepening understanding, the developed quantitative models and sensing technologies presented in this thesis offer practical solutions to support urban development towards a more sustainable and resilient future.

Urban runoff continues to impair water quality and there is an increasing need for stormwater management within the limited confines of urban spaces. We propose a system of structural soil and trees that can be incorporated beneath pavement. Structural soil has a high load-bearing capacity yet is engineered to support tree root growth. Stormwater is directed into a structural soil reservoir below the pavement where tree roots can also thrive. Two container experiments evaluated tree function in this system. We examined whether tree roots can grow into compacted subsoils and if root penetration increases soil infiltration rate. Quercus velutina, Acer rubrum, and a no-tree variant were planted in 26.5 L (7 gal) containers and the rootballs surrounded by compacted clay loam. Roots grew into all layers of the compacted soil. Infiltration rate increased by 63% (+/-2%) compared to no-tree containers. A second experiment evaluated water uptake and tree development in fluctuating water tables. Quercus bicolor and Fraxinus pennsylvanica were planted in 94.6 L (25 gal) containers with structural soils (either Stalite or CU® Structural Soil). Trees were subjected to fluctuating water tables simulating infiltration rates of 2, 1, and 0.1 cm/hr for two growing seasons. Trees thrived in all infiltration regimes but roots were shallower in slowly drained treatments. Trees grew best and transpired the highest water volume with moderate infiltration. Even if trees uptake only small volumes of water, increased canopy size compared to conventional plantings (because of greater penetrable soil volume) allows greater rainfall interception thus decreasing runoff. / Master of Science