Water Sensitive Urban Design Research Articles

A review on microbial contaminants in stormwater runoff and outfalls: Potential health risks and mitigation strategies.

Demands on global water supplies are increasing in response to the need to provide more food, water, and energy for a rapidly growing population. These water stressors are exacerbated by climate change, as well as the growth and urbanisation of industry and commerce. Consequently, urban water authorities around the globe are exploring alternative water sources to meet ever-increasing demands. These alternative sources are primarily treated sewage, stormwater, and groundwater. Stormwater including roof-harvested rainwater has been considered as an alternative water source for both potable and non-potable uses. One of the most significant issues concerning alternative water reuse is the public health risk associated with chemical and microbial contaminants. Several studies to date have quantified fecal indicators and pathogens in stormwater. Microbial source tracking (MST) approaches have also been used to determine the sources of fecal contamination in stormwater and receiving waters. This review paper summarizes occurrence and concentrations of fecal indicators, pathogens, and MST marker genes in urban stormwater. A section of the review highlights the removal of fecal indicators and pathogens through water sensitive urban design (WSUD) or Best Management Practices (BMPs). We also discuss approaches for assessing and mitigating health risks associated with stormwater, including a summary of existing quantitative microbial risk assessment (QMRA) models for potable and non-potable reuse of stormwater. Finally, the most critical research gaps are identified for formulating risk management strategies.

A planning-support tool for spatial suitability assessment of green urban stormwater infrastructure

Distributed green stormwater management infrastructure is increasingly applied worldwide to counter the negative impacts of urbanisation and climate change, while providing a range of benefits related to ecosystem services. They are known as Water Sensitive Urban Design (WSUD) in Australia, Nature Based Solutions (NBS) in Europe, Low Impact Development (LID) in the USA, and Sponge City systems in China. Urban planning for WSUD has been ad-hoc, lacking strategy and resulting in sub-optimal outcomes. The purpose of this study is to help improve strategic WSUD planning and placement through the development of a Planning Support System. This paper presents the development of Spatial Suitability ANalysis TOol (SSANTO), a rapid GIS-based Multi-Criteria Decision Analysis tool using a flexible mix of techniques to map suitability for WSUD assets across urban areas. SSANTO applies a novel WSUD suitability framework, which conceptualises spatial suitability for WSUD implementation from two perspectives: ‘Needs’ and ‘Opportunities’ for WSUD. It combines biophysical as well as socio-economic, planning and governance criteria (‘Opportunities’) with criteria relating to ecosystem services (‘Needs’). Testing SSANTO through comparing its results to work done by a WSUD consultancy successfully verified its algorithms and demonstrated its capability to reflect and potentially enhance the outcomes of planning processes. Manual GIS based suitability analysis is time and resource intensive. Through its rapid suitability analysis, SSANTO facilitates iterative spatial analysis for exploration of scenarios and stakeholder preferences. It thus facilitates collaborative planning and deeper understanding of the relationship between diverse and complex urban contexts and urban planning outcomes for WSUD.

A research of sponge city’s experiment results in Jinan

Sponge city is one of the most important projects in China. It is similar with Australia’s Water Sensitive Urban Design (WSUD). Sponge city plan (SCP) has wrought for three years. Some pilot city has already given some results, like Jinan. This article gives two answers by analyse the current circumstances of this city. One is that the condition of China is different to and other country, which means China cannot just replicate WSUD even they have a similar environment. The other one is that financing is still a problem and Public-private partnerships do not give an enough positive effect as a solution.

Sustainable management of urban water resources through water sensitive urban design (WSUD) in Iran (case study: Rasht city)

سابقه و هدف: شهری حساس در برابر مفهومی با هدف مدیریت پایدار منبع­ های آبی است که ایجاد ارتباط میان برنامه‌ریزی، شهری و منظر با مدیریت پایدار آب شهری را در دستور کار داشته و با بیان راه‌حل‌های با آسیب محیط زیستی کمتر، سعی در بازگرداندن چرخه طبیعی آب در شهر را دارد. این مفهوم برای اولین بار در استرالیا، در سال 1994 مطرح و پس از آن در کشورهای مختلفی از جمله امریکا، آلمان، هلند، استرالیا بکار گرفته شده است. با وجود اقبال شدیدی که این مفهوم بویژه در پهنه­ های باران­خیز داشته و هرچند پهنه­ های وسیعی از ایران جزء این حوزه­ ها بشمار می­ آیند ولی تاکنون پژوهشی در مورد کاربست شهری حساس در برابر آب در ایران انجام نگرفته است. مواد و روش­ ها: این پژوهش در گروه تحقیقات توصیفی-کابردی قرار دارد. در مرحله اول به معرفی رویکرد شهری حساس در برابر آب پرداخته شده است و در مرحلة بعد شاخص­ های این رویکرد بعنوان یک رویکرد مدیریتی یکپارچه در مدیریت آب شهر باران­خیز رشت استخراج شده وسپس سنجش و تحلیل می ­شود و در نهایت، مبتنی بر نتایج حاصل از توصیف شاخص ­ها و ارزیابی آن­ها، راهبردهایی برای بهبود وضعیت مدیریت آب شهر رشت تدوین می ­شود. از آنجا که استخراج ابعاد و شاخص ها به مطالعة دقیق منبع ­ها و سند­ها بستگی دارد، گردآوری داده­ ها با مطالعة اسنادی انجام گرفته است و بمنظور استنباط تکرارپذیر و معتبر بودن داده­ هایی که از اسناد و مدارک به صورت متنی استخراج شده­اند، روش تحلیل محتوا بکار گرفته شده است. از آنجا که شاخص ­ها به لحاظ وزنی یکسان نیستند، پس از استخراج ابعاد و مولفه ­ها و شاخص ­های پرتکرار مدیریت یکپارچه از طریق روش تحلیل محتوا، ضرایب اهمیت هر یک از سطح­هادر سطح بالاتر از طریق پرسشنامة متخصصان (دلفی) به روش وزن­دهی نوسانی لیکرتی پنج تایی محاسبه و در نهایت وزن هر یک از شاخص ­ها تعیین شده است. نتایج و بحث: بر اساس نتیجه پرسشنامه متخصصان، بعد محیط زیستی مهمترین بعد استخراج شده و دو شاخص بهداشت رودخانه­ های شهر و میزان ذخیره آب باران به ترتیب با وزن ­های 0.0469 و 0.0463 بیشترین اهمیت را در پایداری مدیریت آب شهری دارند. در ادامه تحقیق، داده­ های جمع ­آوری شده از طریق مشاهده، پرسشنامه و استفاده از پایگاه داده­ های آماری، وضع موجود شهر رشت در قالب جدول سوات تحلیل شد و با امتیاز وزنی عامل­ های درونی و بیرونی، بر اساس ماتریس GOSP، راهبردهای مناسب در گروه راهبردهای انطباقی تدوین شدند و سپس از طریق ماتریسQSPM راهبردها اولویت­ بندی و در نهایت سیاست ­های مناسب برای کاربست رویکرد شهری حساس در برابر آب در شهر رشت، تدوین شد. تبدیل شبکه زیرساخت خاکستری شهر رشت به شبکه زیرساخت سبز-آبی، بوم ­آشکاری زیرساخت­های سبز به جای لوله ­کشی­ های زیرزمینی، تغییر نگرش نسبت به رابطه بین طبیعت و ساختمان­ ها و افزایش آگاهی شهروندان نسبت به چرخه طبیعی رخ ندادن سیلاب در معابر بهنگام بارندگی ­ها، پاکیزگی رودخانه­ های زرجوب و گوهررود و تالاب­ ها و تبدیل آن­ها به کریدورهای سبز و فضاهای گذران اوقات فراغت، افزایش پوشش گیاهی از سقف­ ها تا نماها و تراس­ ها که تأثیر مثبتی بر درجه حرارت، کیفیت هوا، حیات وحش و سلامت روان خواهد داشت و کاهش مصرف آب شرب در مصرف­ های غیر شرب تا پنجاه درصد (کاهش پنج میلیون لیتر آب شرب فقط از طریق جمع ­آوری آب خاکستری یا آب باران و مصرف آن در فلاش ­تانک­ های ساختمان­ ها)،از جمله سیاست­ های حاصل از کاربست این رویکرد در مدیریت آب این شهر است. نتیجه ­گیری: رویکرد طراحی شهری حساس در برابر آب، بعنوان عقب افتاده­ ترین رویکرد کاربست شهری برای مدیریت پایدار آب شهری، از مدیریت کیفیت رواناب­ های سطحی به سوی یک چارچوب وسیع­ تر برای یکپارچه‌سازی مدیریت آب شهری در ترکیب با شهری، تکامل یافته است و گواهی می­ دهد که امکان مدیریت حضور آب در شهر می ­تواند سیلاب­ها را از مصیبت به نعمت شهری بدل ساخته، ارزش ­های محیط زیستی، اجتماعی و اقتصادی درمحیط­ های شهری، بویژه شهرهای باران­ خیز ایجاد نماید.

A Novel Approach for Delineation of Homogeneous Rainfall Regions for Water Sensitive Urban Design—A Case Study in Southeast Queensland

The delineation of homogeneous regions is primarily based on long-term overall rainfall characteristics and therefore does not necessarily consider the homogeneity of event-based rainfall characteristics. However, event-based rainfall characteristics including antecedent dry days, rainfall intensity, total rainfall and total duration of rainfall events are critical for Water Sensitive Urban Design (WSUD). Accordingly, this study presents a novel approach to objectively identify homogeneous rainfall regions based on event-based rainfall characteristics. This approach uses cluster analysis and Hosking–Wallis heterogeneous tests collectively to test the homogeneity of event-based rainfall characteristics. A case study conducted for southeast Queensland (SEQ), Australia is also presented in this article. This study compares the results of the novel modified approach against results of the conventional approach for the delineation of homogeneous regions. It was evident from the results that the entire SEQ could be treated as a homogeneous rainfall region based on the conventional approach. In contrast, based on the modified approach, the coast and the inland of SEQ were identified as separate homogeneous regions. Further, antecedent dry days and rainfall intensity were recognized as the deciding rainfall characteristics in the delineation of homogeneous rainfall regions.

Non-market value of Singapore's ABC Waters Program

Water sensitive urban design is being promoted in many countries. In Singapore, the Active, Beautiful, Clean (ABC) Waters Programme is a long-term strategic initiative of PUB, Singapore's National Water Agency, to improve the quality of water and urban liveability. While there are some estimates of the bio-physical and ecological benefits of the ABC Waters Programme, information on its social or non-market values is lacking. Using choice experiment datasets this study explores whether people express preferences for ABC Waters features. It also examines whether there is any difference in preferences between respondents living in developments with and without ABC Waters certification, and between respondents living in public and private housing. It is found that respondents living in private housing have substantially higher willingness to pay for ABC Waters features compared to the respondents in public housing. The differences between respondents from certified and non-certified projects were found to be mixed. Such information would be useful to tailor the design of the ABC Waters program. Finally, the potential impact of using a virtual reality tool to present information in a choice experiment towards people's preferences is explored. Application of a virtual reality tool has reduced the proportion of protest voters and increased people's willingness to pay for ABC Waters projects. Thus, this paper contributes to the growing literature on the implications of providing information visually in non-market valuation surveys.

Evaluation of Water Governance Processes Required to Transition towards Water Sensitive Urban Design—An Indicator Assessment Approach for the City of Cape Town

In the face of water related risks resulting from climate change and rapid urbanization, water resources in South African cities have increasingly come under pressure. Following the most recent drought period (2015–2018), local authorities such as the City of Cape Town are being tasked with restructuring policy to include climate change adaptation strategies to adapt more adequately and proactively to these new challenges. This paper describes an evaluation of the water governance processes required to implement Water Sensitive Urban Design (WSUD) in Cape Town—with a specific focus on the barriers to, and opportunities for, those processes related to wastewater treatment, flood risk and the pressing issue of water scarcity. The City Blueprint Approach (CBA) was selected as the indicator assessment approach for this task. The CBA is a set of diagnostic tools comprising the Trends and Pressures Framework, the City Blueprint Framework and the Governance Capacity Framework. This was applied to Cape Town based on in-depth interviews and publicly available information. The analysis revealed that smart monitoring, community knowledge and experimentation with alternative water management technologies are important when considering uncertainties and complexities in the governance of urban water challenges. We conclude that there is potential for Cape Town to transition to a water sensitive city through learning from this experimentation and by implementing WSUD strategies that address water scarcity following the shifts in governance caused by the 2015–2018 drought.

The Reference of Australian Water Sensitive Urban Design Practice to Sponge Cities in China

Water Sensitive Urban Design（WSUD）is a spatial design method which integrates urban design and urban hydrological management. Under the current background of sponge city construction, it promotes the collection, treatment and recycling of rainwater by optimizing the urban material space form, reducing the impact of urban development on natural water circulation system. Water-sensitive urban design was introduced in Australia earlier, and remarkable results have been achieved in design methods and planning practice. Taking WSUD in Australia as an example, this paper elaborates the urban design strategy based on water sensitivity, and draws lessons from Australia's experience in integrating water sensitivity design into practical design and construction at various levels, such as policy, concept, space and technology, in order to provide useful ideas for the construction and development of sponge cities in China and related research in the field of urban design.

Baseflow Contribution from Water Sensitive Urban Design

Baseflow Contribution from Water Sensitive Urban Design

Urban environments sustainable development through low impact approaches

The rapid rate of urbanisation is putting pressure on ecological condition of cities and caused to producing changes on hydrological processes and specially increasing of storm-generated flows and water pollutants. Traditional urban catchment management methods have overlooked many opportunities to perform water-sensitive urban development and public space design strategies, to decrease impacts on the natural water cycle. During recent years, the low impact approaches in urban development have been recommended as an alternative to these traditional stormwater management. The main objective of this paper is to define what low impact approaches are and what they are not, by defining principles and practices and to show the relationship between the principles and implementation actions. This paper reviews the literature on low impact approaches like low-impact development (LID) and low-impact urban design and development (LIUDD) and presents some relevant designing tools and processes that can be used by urban planners and designers in the urban development.

Water Sensitive Urban Design Tool

The 21st century is the century of City and Urbanization. As urban communities spread and populations grow, the impact on the natural environment escalates. The hydrological cycle is among the environmental aspects most impacted by urbanization. Consequently, this study suggests a “Water Sensitive Urban Design Tool” that comprises three dimensions: (i) determining the specific issues facing residential water demand; (ii) identifying the factors influencing these issues; and (iii) the relevant water sustainability objectives and criteria. The WSUD tool could be utilized by urban designers and planners to assess the water performance of residential urban areas. It could be employed to evaluate current conditions, suggested retrofitting options, or Greenfield developments. Thus, the tool not only measures the water sensitivity of residential areas but could also support decision-making and guide development. To evaluate the suggested WSUD tool and examine its suitability to the Egyptian context, particularly the residential sector, a survey was conducted with water-related experts and design specialists. Based on the survey a finalized version of the WSUD Tool was formalized.

Frog occupancy of polluted wetlands in urban landscapes.

Urban sprawl and the rising popularity of water-sensitive urban design of urban landscapes has led to a global surge in the number of wetlands constructed to collect and treat stormwater runoff in cities. However, contaminants, such as heavy metals and pesticides, in stormwater adversely affect the survival, growth, and reproduction of animals inhabiting these wetlands. A key question is whether wildlife can identify and avoid highly polluted wetlands. We investigated whether pond-breeding frogs are attempting to breed in wetlands that affect the fitness of their offspring across 67 urban wetlands in Melbourne, Australia. Frog species richness and the concentration of contaminants (heavy metals and pesticides) were not significantly related, even in the most polluted wetlands. The proportion of fringing vegetation at a wetland had the greatest positive influence on the number of frog species present and the probability of occurrence of individual species, indicating that frogs inhabited wetlands with abundant vegetation, regardless of their pollution status. These wetlands contained contaminant levels similar to urban wetlands around the world at levels that reduce larval amphibian survival. These results are, thus, likely generalizable to other areas, suggesting that urban managers could inadvertently be creating ecological traps in countless cities. Wetlands are important tools for the management of urban stormwater runoff, but their construction should not facilitate declines in wetland-dependent urban wildlife.

Evaluating the reliability of stormwater treatment systems under various future climate conditions

Water Sensitive Urban Design (WSUD) stormwater systems, also known as Low Impact Development (LID) systems or Nature Based Solutions (NBS), are currently implemented based on the underlying assumption of statistical stationarity of rainfall, which threatens to become outdated under climatic uncertainty. This paper applies a new downscaling method to examine the implications of climate change on future rainfall and evaluate the reliability of WSUD stormwater infrastructure in pollution reduction, flow frequency mitigation and reliability as an alternative water supply. A variety of future atmospheric scenarios are considered as part of this comprehensive assessment by analysing an ensemble of eight different downscaled General Circulation Models (GCMs). High resolution catchment-scale rainfall projections for Melbourne, Australia were generated using a scheme called High-resolution Downscaling of Rainfall Using STEPS (HiDRUS) at a fine 1 km and 6-min scale for more precise analysis with uncertainty estimates. Statistical analyses show that, in general, the climate models predict a drier future with fewer rainfall events and longer dry periods when comparing the simulated near future (2040–2049) periods against the base-line period (1995–2004). The difference simulated between historical and future rainfall projections show minimum difference of WSUD performance in pollution removal and flow frequency reduction, with slightly lower harvesting reliability (<3%) observed under future climate; high variabilities, however, were observed across GCM simulations, indicating big uncertainties of system reliability under various conditions, e.g. design wetland sizes may vary from 2.5% to 4.0% of the impervious catchment area according to different future projects across GCMs. Larger WSUD systems are recommended to ensure reliable performance of pollution removal, as well as harvesting reliability under simulated future conditions. The significance of considering an ensemble of different GCMs as opposed to many scenarios generated by a single ‘best’ climate model was also demonstrated for the robust estimation of uncertainty in future WSUD reliability. This work highlights important considerations for the future design, management and quantitative evaluation of WSUD reliability.

Governments and community working together on the SA Catchment to Coast project focusing on water quality improvement across urban Adelaide, 2013–2018

ABSTRACTThe SA Environment Protection Authority (EPA) has led the project ‘Catchment to coast focus for water quality improvement across urban Adelaide’ supporting implementation of the Adelaide Coastal Water Quality Improvement Plan (ACWQIP) released by the EPA in 2013. The ACWQIP followed on from the Adelaide Coastal Waters Study (ACWS) conducted over 2001–2007 in response to concerns of declines in water quality and loss of seagrass. The ACWS indicated that industry and stormwater inputs to the coast were impacting on water quality and seagrass health. Since 2013 discharges from industry have significantly reduced and stormwater is now the main challenge. The Catchment to Coast project, funded by the Australian Government National Landcare Program involved governments and communities working together to improve water quality across Adelaide. Key partnership work included: developing water sensitive urban design demonstration sites, implementing the Rain Garden 500 grant program and working with the Kaurna people, the Traditional Owners to convey cultural messages on the connectedness between people–land–water.

Performance of a kerb side inlet to irrigate street trees and to improve road runoff water quality: a comparison of four media types.

The TREENET inlet is an emerging water-sensitive urban design technology that consists of a novel kerb side inlet coupled with a leaky well infiltration system. The inlets have been retrofitted to existing roads since 2006; however, there is currently little information available on the effectiveness of these inlet and leaky well systems. This study investigated the performance of the kerb side inlets and leaky well system for water quality improvement prior to infiltration to native soil. The leaky wells included four filter media types, namely gravel, water treatment solids, sandy loam and clay. To compare the performance of the four filter media types, batch and column studies were performed in the laboratory. The best performance was observed using the sandy loam as a filter media, followed by clay, water treatment solids and then gravel. The selection of effective media for removal of heavy metals is important as each media type has different pollutant removal capacity, infiltration and clogging performance.

Water Sensitive Urban Design – Principles and Inspiration for Sustainable Stormwater Management in the City of the Future

One of the essential challenges of contemporarysustainable design is to allow humans andnature to coexist in mutual respect, combining thebest aspects of the built landscape with the dynamismand beauty of the environment. Integrating thefunctionality of stormwater management with urbanand landscape design is, therefore, a good example.

A framework to diagnose factors influencing proenvironmental behaviors in water-sensitive urban design

The ongoing challenge of maintaining and improving the quality of water that leaves urban stormwater systems is often addressed using technical rather than social solutions. The need for investment in often expensive water infrastructure can be reduced through better investing in promoting human behaviors that protect water quality as part of water-sensitive urban design (WSUD) initiatives. Successfully achieving this requires understanding factors that influence adoption of proenvironmental behaviors. We review past studies examining this topic and identify that factors influencing adoption of proenvironmental behaviors relevant to WSUD commonly fall into four domains: proenvironmental values and norms, awareness and knowledge of environmental problems and the actions that can address them, proximity and place-based identity, and life-stage and lifestyle factors. We propose the VAIL (values, awareness, identify, lifestyle) framework, based on these four domains and able to be contextualized to specific water-quality problems and individual communities, to assist in diagnosing factors influencing adoption of proenvironmental behaviors. We demonstrate the applicability of the framework in a case study examining adoption of gardening practices that support water quality in Canberra, Australia. We developed 22 locally relevant VAIL indicators and surveyed 3,334 residents to understand engagement in four water-friendly gardening behaviors that help improve water quality in local lakes. In regression modeling, the indicators explained a significant amount of variance in these behaviors and suggested avenues for supporting greater adoption of these behaviors. Predictor variables across all four VAIL domains were significant, highlighting the importance of a multidomain framework.

Building effective Planning Support Systems for green urban water infrastructure—Practitioners’ perceptions

The multiple benefits of adopting distributed, green stormwater technologies in the local environment are increasingly recognised, particularly in relation to water quality, flood mitigation, amenity and aesthetics. To advance the integration of these systems into everyday decision-making practices, Planning Support Systems (PSS) are considered vital. Despite several PSS available to support planners and key decision-makers, their uptake remains constrained; a phenomenon known as the ‘implementation gap’. While scholars have hypothesised why the adoption of PSS is limited, there remains little empirical investigation regarding the reasons why. This paper tests the hypotheses underlying the implementation gap in relation to water sensitive urban design (WSUD) planning. Drawing on the tacit experience of 24 key urban water planning professionals in the front-runner city of Melbourne, Australia, in-depth semi-structured interviews were undertaken to unpack the contemporary planning processes used and reveal characteristics leading to success and failure of PSS application. Data analysis revealed WSUD planning professionals regard the adoption of PSS as a significant step towards improving contemporary decision-making practices, which are regarded as opportunistic rather than strategic. PSS use was widespread, though the type, intensity and sophistication of use varied among interview participants. Confirming the hypotheses from planning literature, practitioners suggested PSS need to be user-friendly and align closely to planning practice. Additionally, however, it was found that it is crucial for PSS to meet industry conventions. Suggested improvements to current PSS included incorporating socio-economic factors alongside biophysical and planning factors, hence the role for GIS-based suitability analysis tools. Overall, this study provides current and future PSS-developers with critical insights regarding the type, function and characteristics of an ‘ideal’ PSS aimed at enhancing the usefulness and uptake of PSS, and thus improve planning that supports expediting green infrastructure implementation.

Strategies for developing transformative capacity in urban water management sectors: The case of Melbourne, Australia

Individuals and organisations are pivotal in changing dominant practices in industry sectors by creating system-level conditions that facilitate transformative change. Yet, the types of agency processes best suited to develop such conditions are not well researched. This paper addresses this gap by empirically investigating how institutional entrepreneurs developed transformative capacity in a successful case of dominant practice change: stormwater management with Water Sensitive Urban Design (WSUD) in the urban water management sector in Melbourne, Australia. We identify ten key strategies that institutional entrepreneurs employed to support the successful introduction, diffusion and establishment of WSUD. By interfacing these strategies with a transformative capacity framework, we describe which combinations of strategies are most relevant for developing different transformative capacity domains across three different phases. The paper contributes to theory on transformative capacity in socio-technical and socio-ecological systems research by providing practical guidance on how transformative capacity can be build up and by distinguishing and describing three distinct phases of transformative capacity development (Introductory Capacity, Diffusional Capacity, Establishment Capacity).

The influence of urban canyon microclimate and contrasting photoperiod on the physiological response of street trees and the potential benefits of water sensitive urban design

Street trees play an important role in helping cities to adapt to multiple environmental perturbations resulting from urbanization, such as changes to the urban water cycle. Biofiltration tree pits are a water sensitive urban design (WSUD) approach that can reduce stormwater runoff and potentially improve runoff quality. Biofiltration tree pits also have the potential to reduce water stress in street trees. This study aimed to monitor the street canyon microclimate of a highly impervious, north-south oriented street canyon in Melbourne, Australia, and the physiological response (carbon assimilation and stomatal conductance) of street trees planted in tree pits within the canyon. Eight trees were examined in total. Four trees were located in biofiltration tree pits (on the western side of the street) and four trees were located in non-biofiltration (conventional) tree pits (on the eastern side of the street). Of the four trees located in each tree pit type, two were Olea europaea L. and two were Eucalyptus olivacea. Microclimate monitoring highlighted the urban canyon’s drastically modified radiative environment due to the urban canyon structure, high atmospheric CO2 concentrations, and elevated air temperature and vapour pressure deficit (VPD). Diurnal gas-exchange was monitored during warm, clear sky conditions and showed the distinct limiting influence that tree photoperiod had on carbon assimilation (A) and stomatal conductance (gs) rates due to urban canyon shading. Regression analyses showed a strong negative relationship between VPD and the A and gs rates of both species while only the A and gs of E. olivacea had a strong positive association with air temperature. While the biofiltration tree pits provided more water to the root zone of the tree and increased soil moisture immediately following rain events, the rapid drainage and drying of the soil meant that plant water availability diminished over time. There was a reduced stomatal conductance for the trees in the biofiltration tree pits during midday (13:00): 0.105 mol m−2 s−1 compared to 0.167 mol m−2 s−1 for O. europaea L.; and 0.281 mol m−2 s−1 compared to 0.344 mol m−2 s−1 for E. olivacea. O. europaea L. appeared to have a higher tolerance of the conditions than E. olivacea. The use of biofiltration trees pits did not appear to be an added benefit or adversity to tree health over the short term but could be improved through more considered tree-pit design.