Ting Fong May Chui

Ting Fong May Chui
The University of Hong Kong | HKU · Department of Civil Engineering

About

78
Publications
17,185
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Introduction
Dr. Ting Fong May Chui is an assistant professor in the Department of Civil Engineering of The University of Hong Kong. She obtained her bachelor degree at Lafayette College, U.S. and completed her M.S. and Ph.D. studies at Stanford University. She then joined National University of Singapore as an assistant professor, and moved back to Hong Kong three years ago.

Publications

Publications (78)
Article
Permeable pavements equipped with an underdrain are one of the most widely used and efficient types of green infrastructure. They can greatly reduce, delay, and retain surface runoff, given their high surface infiltration rate and storage volume; however, their performance in shallow groundwater environments is poorly understood. Based on the monit...
Article
Full-text available
Recent studies have reached inconsistent conclusions from scaling analysis about whether flood or extreme precipitation is more sensitive to warming climate. To explain the reasons behind the inconsistency, here we first used scaling analysis to illustrate how extreme daily precipitation and streamflow scale with daily air temperature across the Co...
Article
We appreciate the comments by Muñoz-Carpena et al. (2021), which pointed out some inconsistency between our work and their results. After a thorough examination, we identified an inaccurate description of the soil hydraulic property model applied in Wu et al. (2021) and an associated error in parameterizing the model in Section 4.1 and Figure 6. Af...
Article
Full-text available
Sustainable urban drainage systems (SuDS) are decentralized stormwater management practices that mimic natural drainage processes. The hydrological processes of SuDS are often modeled using process-based models. However, it can require considerable effort to set up these models. This study thus proposes a machine learning (ML) method to directly le...
Article
Full-text available
The reliability of the machine learning model prediction for a given input can be assessed by comparing it against the actual output. However, in hydrological studies, machine learning models are often adopted to predict future or unknown events, where the actual outputs are unavailable. The prediction accuracy of a model, which measures its averag...
Article
Full-text available
The synergistic effect of urban heat island (UHI) and urban moisture island (UMI) aggravates the heat stress during hot summers. To investigate the mechanisms of UHI and UMI, we developed an advanced urban canopy model with more robust predictability of the urban surface heat and moisture budgets by considering dynamic building-tree-air interaction...
Article
Limitations in current infiltration modeling approaches hamper the evaluation of the effects of complex rainfall pattern and slope gradient on soil infiltration and runoff in presence of a water table (WT), although they can markedly alter the hydrologic processes. To fill the gap, the Smith et al. (1993)’s infiltration model was modified, and a mo...
Article
Tides are one of the main factors affecting coastal aquifers, and thus they are important in supporting material transport and carbon circulation. In coastal mangrove swamps, the groundwater responses to tidal variations become more complicated owing to the complex topography, soil types, and the interactions of groundwater with fauna and flora. Pe...
Article
Deep Bay (DB) is a semi-enclosed bay that opens to the middle part of the Pearl River Estuary (PRE), the largest estuarine wetland area in the world. Like many rivers around the world, the Pearl River has in recent years experienced more frequent and more severe flow variations. It was hypothesized that Pearl River flow variation would affect the e...
Article
Measuring energy fluxes in a dense and high-rise urban area is extremely challenging, thus our knowledge in such area remains limited. This study assessed the surface energy fluxes and investigated the energy balance clo- sure (EBC) over such complex urban surface in Hong Kong. Net radiation (QN), sensible (QH) and latent (QE) heat fluxes were meas...
Article
Measuring energy fluxes in a dense and high-rise urban area is extremely challenging, thus our knowledge in such area remains limited. This study assessed the surface energy fluxes and investigated the energy balance closure (EBC) over such complex urban surface in Hong Kong. Net radiation (Q N), sensible (Q H) and latent (Q E) heat fluxes were mea...
Article
Permeable pavements (PPs) are widely implemented in urban areas to mimic natural hydrologic processes through enhancing infiltration, and reducing, delaying, and retaining surface runoff. However, its performance can be affected by shallow groundwater since high soil moisture may inhibit its infiltration and exfiltration. This study built a numeric...
Article
Full-text available
The hyporheic zone (HZ), the region beneath or alongside a streambed, can play a vital role in a stream ecosystem. Previous studies have examined the impacts of in-stream structures on the HZ and river restoration; however, studies on optimizing the design of in-stream structures are still lacking. Therefore, this study aims to propose a method for...
Article
Most previous studies on mangrove cover have focused on a single study site or environmental factor. There is a lack of regional studies that consider the integrated effects of multiple climatic and hydrological factors on mangrove cover. Multi-year-averaged data can reveal general relationships between mangrove cover and macro- climatic and hydrol...
Article
The hyporheic zone (HZ) plays a vital role in the stream ecosystem. Reactions in the HZ such as denitrification and nitrification have been examined in previous studies. However, no numerical model has yet been developed that can accurately simulate nitrogen concentration changes in the HZ, because the zones for the two reactions can change through...
Conference Paper
Green infrastructures are decentralized semi-natural solutions for managing stormwater runoff. To assess their effectiveness in urban drainage, many process-based hydrological models have been developed. However, these models sometimes fail to deliver satisfactory results due to inadequate representations of the involved hydrological processes or d...
Article
Low impact development (LID) practices are effective in restoring natural hydrological processes, but they may be affected by groundwater and pose additional risk to groundwater dynamics and contamination in shallow groundwater conditions. Their performance in shallow groundwater is not well understood due to monitoring difficulty and the deficienc...
Article
Low impact development (LID) practices are effective in managing surface runoff, mitigating non‐point source pollution and recharging groundwater. However, they are often less effective in shallow groundwater environments as their surface infiltration and bottom exfiltration rates could be reduced, and the underdrains (i.e., underground drains with...
Poster
Full-text available
The hydrologic cycle, as well as the interactive behaviors between hydrologic regime and ecosystem have been greatly altered mainly due to overwhelming urbanization and remarkable transform of land cover. Low impact development (LID) practices are efficient systems to control surface runoff, remediate non-point source pollution, mimic natural hydro...
Article
Attention is increasingly being paid to low impact development (LID) practices in urban stormwater management. Because LID practices offer a wide variety of hydro-environmental benefits, it is often necessary to account for these benefits collectively in cost-benefit analysis and LID alternative selection. The conventional methods of quantifying th...
Article
The hyporheic zone (HZ) plays an important role in stream ecology. Previous studies have mainly focused on the factors influencing the HZ in the steady state. However, the exchange between surface water and groundwater in the HZ can become transient during a storm. This study investigates the impacts of different rainfall patterns (varying in inten...
Article
Low-impact development (LID), best management practice (BMP), and green infrastructure (GI) are semi-engineered stormwater management practices that have been widely studied and implemented worldwide. Implemented in the complex environment of urban areas, LID-BMP-GI practices often intertwine with a very large number of hydro-environmental and soci...
Article
Anthropogenic activities such as land reclamation are threatening tidal marshes worldwide. This study's hypothesis is that land reclamation in a semi-enclosed bay alters the seasonal dynamics of intertidal benthic infauna, which is a key component in the tidal marsh ecosystem. Mai Po Tidal Marsh, Deep Bay, Pearl River Estuary, China was used as a c...
Article
Low impact development (LID) practices are often applied to compensate for surface imperviousness caused by urban development. These practices can mitigate flood risk by reducing runoff volume and peak flow and by delaying the time to peak flow. To select a suitable LID practice type and its surface area during the preliminary design process, it is...
Article
The hyporheic zone is the saturated interstitial space surrounding a stream. Water actively moves into, through, and out of the hyporheic zone, resulting in hyporheic exchange (HE), which is crucial to the physicochemical and biological processes in these systems. The HE in pool-riffle sequences is one of the most common forms of HE and has receive...
Article
Bioretention cells (BCs) have received increasing attention in stormwater quality and quantity management. Selecting a suitable implementation level of BCs to concurrently achieve multiple performance targets (e.g., first flush reduction, peak flow reduction, and runoff volume reduction) is essential and often challenging. This study proposes a met...
Article
Population increase and migration from rural areas to urbanized regions have resulted in the formation of gray cities mainly comprised of impervious surfaces. High quantities of stormwater runoff containing pollutants from gray cities cause problems including inland flooding and water pollution. An innovative and evolving response to this global is...
Article
Full-text available
Permeable pavement (PP) is used worldwide to mitigate surface runoff in urban areas. Various studies have examined the factors governing the hydrologic performance of PP. However, relatively little is known about the relative importance of these governing factors and the long-term hydrologic performance of PP. This study applied numerical models-ca...
Article
Rising sea levels due to climate change are altering the hydrodynamic and solute transport conditions in estuarine regions worldwide. At the same time, anthropogenic projects such as land reclamation could change the potential effects of sea-level rise (SLR). In this study, Deep Bay in the Pearl River Estuary of China was used as a case study to in...
Article
Full-text available
In the eddy covariance technique, lateral heat fluxes in the atmosphere, surfaces, and subsurfaces are often ignored under the assumption of a homogeneous surface. Among lateral heat fluxes, the surface and subsurface fluxes, which might affect the surface energy balance closure over a heterogeneous surface, are less studied. Many wetlands are hete...
Article
The hyporheic zone (HZ), which is the region beneath or alongside a streambed, plays an important role in the stream's ecology. The duration that a water molecule or a solute remains within the HZ, or residence time (RT), is one of the most common metrics used to evaluate the function of the HZ. The RT is greatly influenced by the streambed's hydra...
Article
In the natural environment, soil water repellency decreases infiltration, increases runoff, and increases erosion in slopes. In the built environment, soil water repellency offers the opportunity to develop granular materials with controllable wettability for slope stabilization. In this paper, the influence of soil water repellency on the hydrolog...
Conference Paper
Full-text available
Fire induced soil water repellency (or hydrophobicity) is a major contributor of post-wildfire debris flow. By altering the hydrological responses of soils, the infiltration rate is significantly reduced and surface runoff is enhanced during rainfall events, leading to the erosion and entrainment of slope surface material, and the subsequent format...
Article
Bioretention cells, which are generally effective in controlling surface runoff and recharging groundwater, have been widely adopted as low impact development practices. However, shallow groundwater has limited their implementation in some locations due to the potential problems of a reduction in surface runoff control, groundwater pollution, and c...
Article
Many coastal areas worldwide have been reclaimed to meet the increasing land demand. Understanding the effects of land reclamation on the hydrodynamics and transport processes of a semi-enclosed bay is therefore of significance. From a case study of Deep Bay (DB) in China and referring to idealized bay models, the effects of two types of land recla...
Conference Paper
Full-text available
Water repellent soils, or non-wettable soils, are described as having delayed wetting of the soil surface and water infiltration, and have been studied by soil scientists and agriculturists for decades. Soil water repellency induced by wildfire is believed to be a major trigger of post-fire debris flows, by changing the hydrological characteristics...
Article
Brackish tidal ponds have been constructed along coastal areas in many parts of the world for aquaculture, including some Ramsar Sites. Such ponds are considered a sustainable, wise use of wetlands if managed properly, but they can also pose serious environmental problems if mismanaged. To understand the governing processes and to promote sustainab...
Article
Low impact development (LID) practices (e.g., green roofs, bioretention systems, and porous pavements) offer multiple benefits to urban eco-systems. They reduce the expenses associated with water treatment, grey infrastructure, and energy consumption and thus generate economic benefits. They also benefit the environment by mitigating air pollution...
Article
To achieve better management and conservation, it is important to monitor the salinity of seawater that overlies mudflats and attribute any salinity trend to its potential causes. This study analyzes the salinity trend observed in a semi-enclosed bay and identifies the main causes using numerical modeling. The intertidal mudflat within a Ramsar sit...
Article
To mitigate the impacts of impervious surfaces in urban areas, structures such as bioretention systems and permeable pavements have been installed to enhance infiltration in many countries. However, relatively little knowledge is available regarding the performance of such infiltration-based structures in humid tropical and highly urbanized areas....
Conference Paper
Remote oceanic communities living on low-lying coral islands (atolls) without surface water rely for their survival on the continuing availability of fragile groundwater resources. These exist in the form of fresh groundwater lenses (FGLs) that develop naturally within the porous coral sand and gravel substrate. Coastal hazards such as inundation b...
Article
Sustainable drainage systems (SuDS) reduce surface runoff and pollution from developed areas using various techniques such as green roofs and porous pavements. These systems are becoming popular worldwide, except in highly urbanised cities. This study used contingent valuation to investigate city dwellers' perceptions of SuDS and their willingness...
Article
Full-text available
Low impact development (LID) practices have become more important in urban stormwater management worldwide. However, most research on design optimization focuses on relatively large scale, and there is very limited information or guideline regarding individual LID practice designs (i.e., optimal depth, width and length). The objective of this study...
Article
The decrease of pervious areas during urbanization has severely altered the hydrological cycle, diminishing infiltration and therefore sub-surface flows during rainfall events, and further increasing peak discharges in urban drainage infrastructure. Designing appropriate waster sensitive infrastructure that reduces peak discharges requires a better...
Article
Fresh groundwater lenses (FGLs) are of utmost importance for human survival on small and isolated atolls. This article examines saline damage to atoll FGLs from wave washover caused by storm surge and studies the particular influence of central topographic depressions (CTDs). We model storm surge over atoll islets of contrasting widths (400 and 800...
Article
Urbanization generally increases surface runoff and pollutant loading and decreases infiltration and dry weather flow in canals. Efforts to handle the increased surface runoff, such as widening and deepening canals, further degrade the landscape and riverine habitats. To avert the negative effects of such changes, low-impact development (LID) has b...
Article
Interaction among plants is one of the major processes that drive the health and management of an ecosystem. Such plant–plant interaction, often expressed in terms of biomass yields observed from field or laboratory experiments, reveals the plants' competitiveness for resources such as water and nutrients. In computational modelling of the coupled...
Article
Tension infiltrometers allow water to infiltrate into the soils at various specified pressure heads. The resulting infiltration rates can then be analysed for soil hydraulic properties by either analytical or inverse numerical methods. Tension infiltrometers however are primarily designed to be deployed on horizontal land surfaces, and their applic...
Article
Full-text available
Green structures (e.g. green roof and bio-retention systems) are adopted to mitigate the hydrological impacts of urbanization. However, our current understanding of urbanization impacts are often process-specific (e.g. peak flow or storm recession), and our characterizations of green structures are often on a local scale. This study uses an integra...
Article
Theories that explain the dynamics of ecological communities are still in the developing stage. Yet, practical problems arise where the effects of man-made alterations in the hydrological environment on ecological communities need to be known. The processes involved in such cases are usually poorly understood and long term data and information are...
Article
Human populations inhabiting remote coral atoll islands in the tropical Pacific Ocean rely heavily on thin unconfined fresh groundwater lenses (FWLs) as their main natural source of potable water. Potential threats to the continuing viability of atoll FWLs may be associated with eustatic sea-level rise (SLR), but little is known about the influence...
Conference Paper
Many human populations on remote atoll islands in the Pacific and Indian Ocean rely for their survival on the existence of fragile freshwater lenses, but sea-level rise (SLR) and discrete episodes of marine inundation (e.g. caused by tropical storms or tsunamis) both pose challenges for continuing groundwater viability. Mathematical modelling in th...
Article
Rainfall replenishes surface and subsurface water but is partially intercepted by a canopy. However, it is challenging to quantify the rainfall passing through the canopy (i.e. throughfall). This study derives simple-to-use empirical equations relating throughfall to canopy and rainfall characteristics. Monthly throughfall is calculated by applying...
Article
Full-text available
Green structures (e.g. green roof and bio-retention systems) are adopted to mitigate the hydrological impacts of urbanization. However, our current understanding of the urbanization impacts are often process-specific (e.g. peak flow or storm recession), and our characterizations of green structures are often on a local scale. This study uses an int...
Article
Vulnerability of wetland vegetation to water table changes is a widely studied topic in the field of ecology. Extreme flood or drought conditions imposed on wetlands cause disappearance of plants or shift in the vegetation regime. The recovery of such plant compositions is of particular importance when the wetland is subjected to frequent water tab...
Chapter
Full-text available
The restricted nature of naturally-occurring freshwater resources on atolls is one of the greatest impediments to human settlement on these small, dispersed and remote islands. Any anthropogenic or environmental pressures that deleteriously affect the quantity or quality of atoll water resources are therefore a matter of concern. This chapter focus...
Article
Underground sewage pipe systems deteriorate over time resulting in cracks and joint defects. Sewage thus leaks out and contaminates the surrounding groundwater and the surface water in stormwater drains. Many studies have investigated the problem of sewage leakage but no published studies, to the best knowledge of the authors, have examined the hyd...
Article
Dispersed human populations inhabiting remote atolls across the tropical Pacific Ocean are reliant on the viability of thin freshwater lenses (FWLs) contained within the island coralline sediments for their survival. Yet FWLs are uniquely fragile and easily damaged by saline intrusion. Eustatic sea-level rise (SLR) and sea flooding generated by int...
Article
Wetlands worldwide face drastic degradation from human-induced changes. A small freshwater wetland located within the dense urbanized island state of Singapore---the Nee Soon Wetland---is no exception. It is the only significant locality in Singapore of peat swamp forest and is home to a wide range of rare and endangered floral and faunal species....
Poster
Underground sewers deteriorate over time resulting in cracks and joint defects. Sewage thus leaks out of the sewers and contaminates the surrounding groundwater. Singapore does not directly use groundwater as a water supply. However, contaminated groundwater flows into the drains nearby through weep holes, and subsequently enters water supply reser...
Article
Despite their importance to the natural environment, wetlands worldwide face drastic degradation from changes in land use and climatic patterns. To help preservation efforts and guide conservation strategies, a clear understanding of the dynamic relationship between coupled hydrology and vegetation systems in wetlands, and their responses to engine...
Article
The principal natural source of fresh water on scattered coral atolls throughout the tropical Pacific Ocean is thin unconfined groundwater lenses within islet substrates. Although there are many threats to the viability of atoll fresh water lenses, salinization caused by large storm waves washing over individual atoll islets is poorly understood. I...
Conference Paper
Scattered coral atolls throughout the tropical Pacific Ocean rely heavily on their unconfined groundwater lenses within the islet substrate as freshwater supply. However, these thin groundwater lenses are extremely vulnerable and are subjected to many threats including lens salinisation resulting from islet washover by large waves during severe tro...
Conference Paper
The existence of naturally-occurring freshwater lenses contained within the coralline substrate of atoll islets is absolutely critical for sustaining human habitation in these harsh environments. Yet, atoll freshwater lenses are uniquely fragile and therefore highly vulnerable to a range of human and natural disturbances. Of several possible threat...
Article
Wetlands constitute 6 - 7 % of the Earth's land surface and provide various critical ecosystem services such as purifying the air and water, mitigating floods and droughts, and supporting wildlife habitats. Despite the importance of wetlands, they are under threat of degradation by human-induced land use changes and climate change. Even if the valu...
Article
Modeling of hydrologic processes using multiphysics modeling packages shows significant promise in a number of applications. However, these packages have not yet developed a complete set of implementations for boundary conditions important in hydrologic modeling. Three such boundary conditions-rainfall infiltration, seepage faces, and evapotranspir...
Article
The surface elevation of Searsville Reservoir, CA, as well as the piezometric head of the surrounding ground water, fluctuates diurnally during the summer months due to evapotranspiration (ET). The objective of this study is to try to understand the diurnal signals in fully-coupled and interacting groundwater surface-water systems like Searsville u...
Article
One approach for simulating ground water-lake interactions is to incorporate the lake into the ground water solution domain as a high-conductivity region. Previous studies have developed this approach using fully saturated models. This study extends this approach to variably saturated models, so that ground water-lake interactions may be more easil...
Article
Hydrological processes and components are intrinsically coupled, and thus often must be modeled as an integrated system. Unfortunately, although a few modeling codes are available, integrated hydrological modeling remains a challenge. The objective of this paper is to explore the feasibility of using COMSOL Multiphysics® for integrated hydrological...
Article
Searsville Reservoir is located within Jasper Ridge Biological Preserve in California, U.S.A. Not only is it a source of non-potable water and the home of various aquatic species, it has also created a wetland habitat on the alluvial floodplains. However, it is expected to be filled up with sediment in the next few decades, causing problems such as...

Projects

Projects (3)
Archived project
Improve understanding of fresh groundwater lens responses on low-lying atoll islands to 1. sea-level rise and 2. salinization and recovery following washover by storm waves.