Journal of Water Resources Planning and Management, 2017
AbstractAs watersheds are urbanized, the amount of impervious surfaces will be increased. As such... more AbstractAs watersheds are urbanized, the amount of impervious surfaces will be increased. As such, water infiltration will be reduced, and the volume of surface runoff will be increased. By retaini...
Light detection and ranging (LiDAR) and four-channel red, green, blue, and near-infrared (RGBI) r... more Light detection and ranging (LiDAR) and four-channel red, green, blue, and near-infrared (RGBI) remote sensed imageries allow an accurate quantification and contiguous measurement of vegetation characteristics and forest structures. This information facilitates the generation of habitat structure variables for forest species distribution modelling. However, applications of remote sensing data, especially the combination of structural and spectral information, to support evidence-based decisions in forest managements and conservation practices at local scale are not widely adopted. In this study, we examined the habitat requirements of pileated woodpecker (Dryocopus pileatus) (PW) in Hamilton County, Ohio, using ecologically relevant forest structural and vegetation characteristics derived from LiDAR and RGBI data. We hypothesized that the habitat of PW is shaped by vegetation characteristics that are directly associated with the availability of food, hiding and nesting resources, the spatial arrangement of habitat patches within home range, as well as proximity to water sources. We used 186 PW presence or absence locations to model their presence and absence in generalized additive model (GAM) at two scales, representing foraging and home range size, respectively. The results confirm PW's preference for tall and large mature stands with structural complexity, typical of late-successional or old-growth forests. Besides, the crown size of dead trees shows a positive relationship with PW occurrence, therefore indicating the importance of declining living trees or early-stage dead trees within PW home range. These locations are preferred by PW for nest cavity excavation as it attempts to balance the ease of excavation and tree security. In addition, we found that PW can adjust its travel distance to the nearest water resource, suggesting that habitat fragmentation can have certain impacts on PW. Based on our findings, we recommend that forest managers should use different priorities to manage nesting, roosting, and feeding habitats. Particularly, when devising forest management and hazard tree removal plans, one needs to consider retaining enough cavity trees within high-quality PW habitat. By mapping PW habitat suitability for the study area, we highlight the importance of riparian corridor in facilitating PW to adjust to the fragmented urban landscape. Indeed, habitat improvement for PW in the study area could be achieved by conserving riparian corridors and promoting riparian forest succession along major rivers in Hamilton County. (The acronyms used in this paper are listed in Table A1 of the Appendix.
With the population increasing and land use patterns changing, there will be environmental conseq... more With the population increasing and land use patterns changing, there will be environmental consequences. To solve these impending problems, information on the future land use pattern is needed. This study attempted to develop an enhanced land use model, capable of predicting future conditions. The traditional Markov model was modified by incorporating a Cellular Automata (CA) and a population variable to depict the neighboring effects and the impacts of population growth on urbanization. The performance of this new model was quantitatively assessed by generating the 2001 land use patterns of the East Fork Little Miami River watershed in southwest Ohio with and without the CA and the population variable and compared with the actual 2001 land use imagery. From the comparison, it was apparent that the land use map generated with the CA and population variable was more accurate. To further ascertain its applicability in a larger watershed, the same procedure was used to model the entire...
Best Management Practices (BMPs) are commonly adopted to ameliorate the quality of runoff and red... more Best Management Practices (BMPs) are commonly adopted to ameliorate the quality of runoff and reduce the frequency and intensity of flash floods in urban areas. To date, many of the BMP studies are conducted using coarse resolution data. However, the accuracy of such studies may be compromised due to the shortcomings inherent in the input data; as such, the evaluation of the BMP cost-effectiveness may not be accurate. The objective of this paper is to demonstrate the improvements of higher resolution images over coarse resolution data in BMP analyses. An unmanned aerial vehicle (UAV) was used to collect a more detailed and accurate picture of the digital surface model and digital elevation model. Landsat 8 multi-spectral imagery was classified by object-oriented classification to generate a land use/land cover map. The method used in this study provided more detailed and accurate information of the physical conditions of the study area, an improved subwatershed delineation, a more comprehensive list of the suitable locations for BMPs, and a more reliable estimate of the cost-effectiveness of the BMP ensembles than that generated using coarse resolution data. Using the fine resolution data, this study further determined the utility of the selected BMP ensembles under a changed future climate regime and identified the best BMP and BMP ensemble in reducing urban surface runoff. This method can be especially useful in areas without quality topography and land use data.
A cell-based model for the Las Vegas Wash Watershed in Clark County, Nevada, USA, was developed b... more A cell-based model for the Las Vegas Wash Watershed in Clark County, Nevada, USA, was developed by combining the Thornthwaite water balance model and the Soil Conservation Survey's Curve Number method with pixel-based computing technology. After the model was validated, it was used to predict the 2030 and 2050 hydrologic conditions under future scenarios of climate and land-use changes. The future climate projections were based on the Intergovernmental Panel on Climate Change (IPCC) B1 climate scenario, and the land-use scenarios were derived from a CA-Markov landuse model. Results indicate that under these hypothetical conditions, the future surface runoff in the watershed will significantly decrease in winters but increase in summers. Climate change will be the primary controlling factor over runoff. Urban development is projected to increase runoff and may contribute 1.1-18.7% of the changes. This finding may be useful in devising future urban development plans and water management policies.
Infrastructures and population distribution form the urban structure and social fabric, in which ... more Infrastructures and population distribution form the urban structure and social fabric, in which water and other environmental qualities change through the urban metabolism described in Timmerman and White (1997). In this context, sustainable and green urban growth poses a challenge to the ability of urban process analysis and system modeling for adaptation. We have accustomed to evaluating developmental scenario and quantifying its sustainability mostly by a single attribute. Rarely is a scenario of smart development analyzed and optimized through a matrix of environmental and socioeconomic greenness variables: water resource utilization in water footprint, energy consumption in carbon footprint and climate change effects, and importantly socioeconomic efficiencies. Due to the complex interactions in urban metabolism, only system-scale holistic analysis offers a scientific basis to compare and optimize future development scenarios. In this system analysis, a planning-modeling-optim...
Management of Environmental Quality: An International Journal, 2021
PurposeThis study aims to further understand the factors contributory to fire occurrences in two ... more PurposeThis study aims to further understand the factors contributory to fire occurrences in two semi-arid regions in the American Southwest, Clark County in Nevada and Maricopa and Pinal Counties in Arizona.Design/methodology/approachStatistical and geographic information system analyses were employed to examine the spatial and temporal relationships of various natural and human-caused factors with fire incidences.FindingsAngström fire danger index, average amount of rainfall one month prior, extent of forests and grasslands, and proximities to secondary roads and population centers have significant relationships with fire events.Research limitations/implicationsThe importance of the factors contributory to fire occurrence is site-specific even in areas with similar climatic regimes and varies among different geographic regions; as such, researchers will need to conduct specific investigation of each study area.Practical implicationsThe findings of this study can be instrumental in...
Highly productive, diverse, and ecologically important riparian ecosystems in the southwestern Un... more Highly productive, diverse, and ecologically important riparian ecosystems in the southwestern United States have declined 90% since historic times. Since at least 60% of all vertebrate species and 70% of the rare, threatened, and endangered species, such as the southwestern willow flycatcher (Empidonax traillii extimus), depend on riparian zones in semi-arid environments, it is imperative to document, quantify, and characterize the changes in these habitats. This information will be instrumental for managers, planners, and decision-makers to further understand the potential environmental and biological vulnerability of the area and take action to reduce the vulnerability and to conserve or restore these important riparian ecosystems. To achieve this aim, we introduce an original change detection methodology using color-infrared aerial photography, ENVI’s SPEAR Vegetation Delineation Tool, and geographic information systems. This technique significantly reduces processing time and e...
In this paper, we examine the combined water quality impacts offuture land-use and climate change... more In this paper, we examine the combined water quality impacts offuture land-use and climate changes in the Little Miami River Watershed in southwestern Ohio. It is important to quantify these impacts because this information will allow us to make changes to the current water resource allocations in order to cope with future conditions. To simulate future land-use conditions, we used the existing future land-use development plans of the eleven counties comprising the watershed. Future climate changes were simulated using results from recent Global Circulation Models. By calibrating and validating an integrated watershed-scale hydrological model (Soil and Water Assessment Tool), we were able to quantify the changes in runoff and nonpoint source pollution, which would occur under the projected future environmental conditions. Model results indicate that, under future land-use and climate conditions, average pollutant loads and daily concentrations are reduced. The total phosphorus conce...
International Journal of Applied Earth Observation and Geoinformation
Abstract High quality land use/land cover (LULC) data with fine spatial resolution and frequent t... more Abstract High quality land use/land cover (LULC) data with fine spatial resolution and frequent temporal coverage are indispensable for revealing detail information of the Earth’s surface, characterizing LULC of the area, predicting the plausible land use changes, and assessing the viability and impacts of any development plans. While airborne imagery has high spatial resolution, it only provides limited temporal coverage over time. The LULC data from historical remote sensing images, such as those from Landsat, have frequent coverages over a long temporal period, but their spatial resolutions are low. This paper presents a spatio-temporal Cokriging method to sharpen LULC data and predict the trends of land use change. A set of time-series coarse resolution LULC maps and one frame of high spatial resolution airborne imagery of the Upper Mill Creek Watershed were used to illustrate the utility of our method. By explicitly describing the spatio-temporal dependence within and between different datasets, modelling the Anderson classification codes using spatial, temporal, and cross-covariance structures, and transforming the Anderson integer classification code to class probability, our method was able to resolve the differences between multi-source spatio-temporal LULC data, generate maps with sharpened and detailed land features, characterize the spatial and temporal LULC changes, reveal the trend of LULC change, and create a quality dataset invaluable for monitoring, assessing, and modelling LULC changes.
ABSTRACT The growth of vegetation in polluted areas with leachate seepage of the landfill at Gin ... more ABSTRACT The growth of vegetation in polluted areas with leachate seepage of the landfill at Gin Drinkers Bay, Hong Kong (latitude: 22°21′; longitude: 114°07′) was poor. High contents of total as well as extractable (by ammonium acetate at pH 7) Mn, Cu, Pb and Zn were revealed in soil samples of these polluted areas.Detailed investigation of the effects of the landfill leachate on seed germination and root growth of and was carried out under laboratory conditions. Seed germination and root elongation of both species were retarded at high concentrations (above 25% v/v) of the leachate. However, low concentrations of leachate resulted in higher germinability and longer root length of when compared with the control.The values of EC50 (effective concentration in reducing root length to 50% of the control) were also used to compare the toxic effects of the leachate on root elongation of the two species. It was noted that showed similar values of EC50 at different time intervals tested (518–615%) whereas showed no effective value at 48h, and progressively higher values were obtained with increasing time (72h-EC50: 5%; 96h-EC50: 13.3%; 144h-EC50: 28.5%).From the results of the present investigation it is concluded that the rather high contents of heavy metals in the leachate may have harmful effects on both seed germination and root growth although organic substances might also play an important role.
Abstract Soil and foliage samples were collected from 15 groves of American elders in the Mt. Air... more Abstract Soil and foliage samples were collected from 15 groves of American elders in the Mt. Airy Forest, Cincinnati, and tested for lead and copper concentrations. Analysis of variance revealed significant reduction of foliar copper and soil lead contents with ...
In this paper, we examine the combined water quality impacts offuture land-use and climate change... more In this paper, we examine the combined water quality impacts offuture land-use and climate changes in the Little Miami River Watershed in southwestern Ohio. It is important to quantify these impacts because this information will allow us to make changes to the current water resource allocations in order to cope with future conditions. To simulate future land-use conditions, we used the existing future land-use development plans of the eleven counties comprising the watershed. Future climate changes were simulated using results from recent Global Circulation Models. By calibrating and validating an integrated watershed-scale hydrological model (Soil and Water Assessment Tool), we were able to quantify the changes in runoff and nonpoint source pollution, which would occur under the projected future environmental conditions. Model results indicate that, under future land-use and climate conditions, average pollutant loads and daily concentrations are reduced. The total phosphorus concentration decreased from 3.0 mg/L to 1.2 mg/L, demonstrating that sound land-use management schemes can work to reduce the eutrophication problem. In the Little Miami River, eutrophication is caused by an overabundance of phosphorus. However, the fact that the new phosphorus concentration level still exceeds EPA's suggested limit indicates that other practices, in addition to land-use changes, will be needed to mitigate the adverse water quality impacts ofclimate change.
Journal of Water Resources Planning and Management, 2017
AbstractAs watersheds are urbanized, the amount of impervious surfaces will be increased. As such... more AbstractAs watersheds are urbanized, the amount of impervious surfaces will be increased. As such, water infiltration will be reduced, and the volume of surface runoff will be increased. By retaini...
Light detection and ranging (LiDAR) and four-channel red, green, blue, and near-infrared (RGBI) r... more Light detection and ranging (LiDAR) and four-channel red, green, blue, and near-infrared (RGBI) remote sensed imageries allow an accurate quantification and contiguous measurement of vegetation characteristics and forest structures. This information facilitates the generation of habitat structure variables for forest species distribution modelling. However, applications of remote sensing data, especially the combination of structural and spectral information, to support evidence-based decisions in forest managements and conservation practices at local scale are not widely adopted. In this study, we examined the habitat requirements of pileated woodpecker (Dryocopus pileatus) (PW) in Hamilton County, Ohio, using ecologically relevant forest structural and vegetation characteristics derived from LiDAR and RGBI data. We hypothesized that the habitat of PW is shaped by vegetation characteristics that are directly associated with the availability of food, hiding and nesting resources, the spatial arrangement of habitat patches within home range, as well as proximity to water sources. We used 186 PW presence or absence locations to model their presence and absence in generalized additive model (GAM) at two scales, representing foraging and home range size, respectively. The results confirm PW's preference for tall and large mature stands with structural complexity, typical of late-successional or old-growth forests. Besides, the crown size of dead trees shows a positive relationship with PW occurrence, therefore indicating the importance of declining living trees or early-stage dead trees within PW home range. These locations are preferred by PW for nest cavity excavation as it attempts to balance the ease of excavation and tree security. In addition, we found that PW can adjust its travel distance to the nearest water resource, suggesting that habitat fragmentation can have certain impacts on PW. Based on our findings, we recommend that forest managers should use different priorities to manage nesting, roosting, and feeding habitats. Particularly, when devising forest management and hazard tree removal plans, one needs to consider retaining enough cavity trees within high-quality PW habitat. By mapping PW habitat suitability for the study area, we highlight the importance of riparian corridor in facilitating PW to adjust to the fragmented urban landscape. Indeed, habitat improvement for PW in the study area could be achieved by conserving riparian corridors and promoting riparian forest succession along major rivers in Hamilton County. (The acronyms used in this paper are listed in Table A1 of the Appendix.
With the population increasing and land use patterns changing, there will be environmental conseq... more With the population increasing and land use patterns changing, there will be environmental consequences. To solve these impending problems, information on the future land use pattern is needed. This study attempted to develop an enhanced land use model, capable of predicting future conditions. The traditional Markov model was modified by incorporating a Cellular Automata (CA) and a population variable to depict the neighboring effects and the impacts of population growth on urbanization. The performance of this new model was quantitatively assessed by generating the 2001 land use patterns of the East Fork Little Miami River watershed in southwest Ohio with and without the CA and the population variable and compared with the actual 2001 land use imagery. From the comparison, it was apparent that the land use map generated with the CA and population variable was more accurate. To further ascertain its applicability in a larger watershed, the same procedure was used to model the entire...
Best Management Practices (BMPs) are commonly adopted to ameliorate the quality of runoff and red... more Best Management Practices (BMPs) are commonly adopted to ameliorate the quality of runoff and reduce the frequency and intensity of flash floods in urban areas. To date, many of the BMP studies are conducted using coarse resolution data. However, the accuracy of such studies may be compromised due to the shortcomings inherent in the input data; as such, the evaluation of the BMP cost-effectiveness may not be accurate. The objective of this paper is to demonstrate the improvements of higher resolution images over coarse resolution data in BMP analyses. An unmanned aerial vehicle (UAV) was used to collect a more detailed and accurate picture of the digital surface model and digital elevation model. Landsat 8 multi-spectral imagery was classified by object-oriented classification to generate a land use/land cover map. The method used in this study provided more detailed and accurate information of the physical conditions of the study area, an improved subwatershed delineation, a more comprehensive list of the suitable locations for BMPs, and a more reliable estimate of the cost-effectiveness of the BMP ensembles than that generated using coarse resolution data. Using the fine resolution data, this study further determined the utility of the selected BMP ensembles under a changed future climate regime and identified the best BMP and BMP ensemble in reducing urban surface runoff. This method can be especially useful in areas without quality topography and land use data.
A cell-based model for the Las Vegas Wash Watershed in Clark County, Nevada, USA, was developed b... more A cell-based model for the Las Vegas Wash Watershed in Clark County, Nevada, USA, was developed by combining the Thornthwaite water balance model and the Soil Conservation Survey's Curve Number method with pixel-based computing technology. After the model was validated, it was used to predict the 2030 and 2050 hydrologic conditions under future scenarios of climate and land-use changes. The future climate projections were based on the Intergovernmental Panel on Climate Change (IPCC) B1 climate scenario, and the land-use scenarios were derived from a CA-Markov landuse model. Results indicate that under these hypothetical conditions, the future surface runoff in the watershed will significantly decrease in winters but increase in summers. Climate change will be the primary controlling factor over runoff. Urban development is projected to increase runoff and may contribute 1.1-18.7% of the changes. This finding may be useful in devising future urban development plans and water management policies.
Infrastructures and population distribution form the urban structure and social fabric, in which ... more Infrastructures and population distribution form the urban structure and social fabric, in which water and other environmental qualities change through the urban metabolism described in Timmerman and White (1997). In this context, sustainable and green urban growth poses a challenge to the ability of urban process analysis and system modeling for adaptation. We have accustomed to evaluating developmental scenario and quantifying its sustainability mostly by a single attribute. Rarely is a scenario of smart development analyzed and optimized through a matrix of environmental and socioeconomic greenness variables: water resource utilization in water footprint, energy consumption in carbon footprint and climate change effects, and importantly socioeconomic efficiencies. Due to the complex interactions in urban metabolism, only system-scale holistic analysis offers a scientific basis to compare and optimize future development scenarios. In this system analysis, a planning-modeling-optim...
Management of Environmental Quality: An International Journal, 2021
PurposeThis study aims to further understand the factors contributory to fire occurrences in two ... more PurposeThis study aims to further understand the factors contributory to fire occurrences in two semi-arid regions in the American Southwest, Clark County in Nevada and Maricopa and Pinal Counties in Arizona.Design/methodology/approachStatistical and geographic information system analyses were employed to examine the spatial and temporal relationships of various natural and human-caused factors with fire incidences.FindingsAngström fire danger index, average amount of rainfall one month prior, extent of forests and grasslands, and proximities to secondary roads and population centers have significant relationships with fire events.Research limitations/implicationsThe importance of the factors contributory to fire occurrence is site-specific even in areas with similar climatic regimes and varies among different geographic regions; as such, researchers will need to conduct specific investigation of each study area.Practical implicationsThe findings of this study can be instrumental in...
Highly productive, diverse, and ecologically important riparian ecosystems in the southwestern Un... more Highly productive, diverse, and ecologically important riparian ecosystems in the southwestern United States have declined 90% since historic times. Since at least 60% of all vertebrate species and 70% of the rare, threatened, and endangered species, such as the southwestern willow flycatcher (Empidonax traillii extimus), depend on riparian zones in semi-arid environments, it is imperative to document, quantify, and characterize the changes in these habitats. This information will be instrumental for managers, planners, and decision-makers to further understand the potential environmental and biological vulnerability of the area and take action to reduce the vulnerability and to conserve or restore these important riparian ecosystems. To achieve this aim, we introduce an original change detection methodology using color-infrared aerial photography, ENVI’s SPEAR Vegetation Delineation Tool, and geographic information systems. This technique significantly reduces processing time and e...
In this paper, we examine the combined water quality impacts offuture land-use and climate change... more In this paper, we examine the combined water quality impacts offuture land-use and climate changes in the Little Miami River Watershed in southwestern Ohio. It is important to quantify these impacts because this information will allow us to make changes to the current water resource allocations in order to cope with future conditions. To simulate future land-use conditions, we used the existing future land-use development plans of the eleven counties comprising the watershed. Future climate changes were simulated using results from recent Global Circulation Models. By calibrating and validating an integrated watershed-scale hydrological model (Soil and Water Assessment Tool), we were able to quantify the changes in runoff and nonpoint source pollution, which would occur under the projected future environmental conditions. Model results indicate that, under future land-use and climate conditions, average pollutant loads and daily concentrations are reduced. The total phosphorus conce...
International Journal of Applied Earth Observation and Geoinformation
Abstract High quality land use/land cover (LULC) data with fine spatial resolution and frequent t... more Abstract High quality land use/land cover (LULC) data with fine spatial resolution and frequent temporal coverage are indispensable for revealing detail information of the Earth’s surface, characterizing LULC of the area, predicting the plausible land use changes, and assessing the viability and impacts of any development plans. While airborne imagery has high spatial resolution, it only provides limited temporal coverage over time. The LULC data from historical remote sensing images, such as those from Landsat, have frequent coverages over a long temporal period, but their spatial resolutions are low. This paper presents a spatio-temporal Cokriging method to sharpen LULC data and predict the trends of land use change. A set of time-series coarse resolution LULC maps and one frame of high spatial resolution airborne imagery of the Upper Mill Creek Watershed were used to illustrate the utility of our method. By explicitly describing the spatio-temporal dependence within and between different datasets, modelling the Anderson classification codes using spatial, temporal, and cross-covariance structures, and transforming the Anderson integer classification code to class probability, our method was able to resolve the differences between multi-source spatio-temporal LULC data, generate maps with sharpened and detailed land features, characterize the spatial and temporal LULC changes, reveal the trend of LULC change, and create a quality dataset invaluable for monitoring, assessing, and modelling LULC changes.
ABSTRACT The growth of vegetation in polluted areas with leachate seepage of the landfill at Gin ... more ABSTRACT The growth of vegetation in polluted areas with leachate seepage of the landfill at Gin Drinkers Bay, Hong Kong (latitude: 22°21′; longitude: 114°07′) was poor. High contents of total as well as extractable (by ammonium acetate at pH 7) Mn, Cu, Pb and Zn were revealed in soil samples of these polluted areas.Detailed investigation of the effects of the landfill leachate on seed germination and root growth of and was carried out under laboratory conditions. Seed germination and root elongation of both species were retarded at high concentrations (above 25% v/v) of the leachate. However, low concentrations of leachate resulted in higher germinability and longer root length of when compared with the control.The values of EC50 (effective concentration in reducing root length to 50% of the control) were also used to compare the toxic effects of the leachate on root elongation of the two species. It was noted that showed similar values of EC50 at different time intervals tested (518–615%) whereas showed no effective value at 48h, and progressively higher values were obtained with increasing time (72h-EC50: 5%; 96h-EC50: 13.3%; 144h-EC50: 28.5%).From the results of the present investigation it is concluded that the rather high contents of heavy metals in the leachate may have harmful effects on both seed germination and root growth although organic substances might also play an important role.
Abstract Soil and foliage samples were collected from 15 groves of American elders in the Mt. Air... more Abstract Soil and foliage samples were collected from 15 groves of American elders in the Mt. Airy Forest, Cincinnati, and tested for lead and copper concentrations. Analysis of variance revealed significant reduction of foliar copper and soil lead contents with ...
In this paper, we examine the combined water quality impacts offuture land-use and climate change... more In this paper, we examine the combined water quality impacts offuture land-use and climate changes in the Little Miami River Watershed in southwestern Ohio. It is important to quantify these impacts because this information will allow us to make changes to the current water resource allocations in order to cope with future conditions. To simulate future land-use conditions, we used the existing future land-use development plans of the eleven counties comprising the watershed. Future climate changes were simulated using results from recent Global Circulation Models. By calibrating and validating an integrated watershed-scale hydrological model (Soil and Water Assessment Tool), we were able to quantify the changes in runoff and nonpoint source pollution, which would occur under the projected future environmental conditions. Model results indicate that, under future land-use and climate conditions, average pollutant loads and daily concentrations are reduced. The total phosphorus concentration decreased from 3.0 mg/L to 1.2 mg/L, demonstrating that sound land-use management schemes can work to reduce the eutrophication problem. In the Little Miami River, eutrophication is caused by an overabundance of phosphorus. However, the fact that the new phosphorus concentration level still exceeds EPA's suggested limit indicates that other practices, in addition to land-use changes, will be needed to mitigate the adverse water quality impacts ofclimate change.
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Papers by Susanna Tong