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In this study we present the Portland State University Active Rock Glacier Inventory (n=10 332) for the contiguous United States, derived from the manual classification of remote sensing imagery (Johnson, 2020; https://doi.org/10.1594/PANGAEA.918585). Individually, these active rock glaciers are found across widely disparate montane environments, but their overall distribution unambiguously favors relatively high, arid mountain ranges with sparse vegetation. While at least one active rock glacier is identified in each of the 11 westernmost states, nearly 88 % are found in just five states: Colorado (n=3889), Montana (n=1813), Idaho (n=1689), Wyoming (n=839), and Utah (n=834). Mean active rock glacier area is estimated at 0.10 km2, with cumulative active rock glacier area totaling 1004.05 km2. Active rock glaciers are assigned to a three-tier classification system based on area thresholds and surface characteristics known to correlate with downslope movement. Class 1 features (n=7042, average area = 0.12 km2) appear to be highly active, Class 2 features (n=2415, average area = 0.05 km2) appear to be intermediately active, and Class 3 features (n=875, average area = 0.04 km2) appear to be minimally active. This geospatial inventory will allow past active rock glacier research findings to be spatially extrapolated, help facilitate further active rock glacier research by identifying field study sites, and serve as a valuable training set for the development of automated rock glacier identification and classification methods applicable to other large regional studies.
Gunnar Johnson; Heejun Chang; Andrew Fountain. Active rock glaciers of the contiguous United States: geographic information system inventory and spatial distribution patterns. Earth System Science Data 2021, 13, 3979 -3994.
AMA StyleGunnar Johnson, Heejun Chang, Andrew Fountain. Active rock glaciers of the contiguous United States: geographic information system inventory and spatial distribution patterns. Earth System Science Data. 2021; 13 (8):3979-3994.
Chicago/Turabian StyleGunnar Johnson; Heejun Chang; Andrew Fountain. 2021. "Active rock glaciers of the contiguous United States: geographic information system inventory and spatial distribution patterns." Earth System Science Data 13, no. 8: 3979-3994.
Glacier-dependent streams and irrigation systems in the Hood River Watershed (HRW) are particularly vulnerable to climate change, as glaciers retreat and snowpack declines. We developed a System Dynamics model designed to test and improve resilience of the HRW’s socio-hydrological system under CMIP5 climate change scenarios and irrigation infrastructure improvement, water banking, and water conservation. We hypothesized irrigators’ potential strategies would increase adaptive capacity by ensuring sufficient water resources for irrigation and minimum streamflow for fish habitat. Our model suggested predicted temperature increases will cause a lengthening of the dry season, causing streamflow declines, but adaptive measures have the potential to increase the capacity of the socio-hydrological system to “bounce back” from strains on streamflow given collective cooperation and the acceptance of agriculture-ecology tradeoffs. Hence, we found that System Dynamics models offer useful tools for simulating localized potential impacts of climate change and developing possible solutions to improve resilience.
Alexander Reid Ross; Heejun Chang. Modeling the system dynamics of irrigators’ resilience to climate change in a glacier-influenced watershed. Hydrological Sciences Journal 2021, 1 .
AMA StyleAlexander Reid Ross, Heejun Chang. Modeling the system dynamics of irrigators’ resilience to climate change in a glacier-influenced watershed. Hydrological Sciences Journal. 2021; ():1.
Chicago/Turabian StyleAlexander Reid Ross; Heejun Chang. 2021. "Modeling the system dynamics of irrigators’ resilience to climate change in a glacier-influenced watershed." Hydrological Sciences Journal , no. : 1.
La gestión del agua en las ciudades se ha vuelto cada más desafiante, debido al aumento de la demanda urbana de agua en un contexto de reducción de las fuentes disponibles. Estos problemas han evidenciado la necesidad de integrar el abastecimiento de agua, el drenaje y el saneamiento desde el paradigma de la Gestión Integrada del Agua Urbana (GIAU). Para el estudio del componente de abastecimiento es importante considerar el análisis de los determinantes de la demanda urbana de agua. En el caso de la Ciudad de México no se cuenta con un diagnóstico certero de estos determinantes a pesar de que enfrenta múltiples problemas en materia hídrica. Por lo que, el objetivo de este trabajo consiste en estimar la demanda doméstica de agua y sus determinantes en la Ciudad de México a escala de colonias para el año 2010, con base en datos oficiales medidos. Los determinantes analizados se relacionan con cuestiones socioeconómicos, densidad urbana y acceso al agua; utilizando los modelos de regresión múltiple de Mínimos Cuadrados (que provee resultados globales y espacialmente estacionarios) y de Regresión Geográficamente Ajustada (que presenta coeficientes que varían espacialmente). Los resultados señalan que el área central de la ciudad es prioritaria para implementar estrategias desde la GIAU. Esta estimación aporta a una comprensión más profunda de la crisis de agua en la Ciudad de México desde la visión de la demanda de agua, además de ser útil para la toma de decisiones.
Arturo Ramos-Bueno; Universidad Nacional Autónoma De México Posgrado En Geografía; María Perevochtchikova; Heejun Chang; Urbanos Y Ambientales Centro De Estudios Demográficos. Socio-spatial analysis of residential water demand in Mexico City. Tecnología y ciencias del agua 2021, 12, 59 -110.
AMA StyleArturo Ramos-Bueno, Universidad Nacional Autónoma De México Posgrado En Geografía, María Perevochtchikova, Heejun Chang, Urbanos Y Ambientales Centro De Estudios Demográficos. Socio-spatial analysis of residential water demand in Mexico City. Tecnología y ciencias del agua. 2021; 12 (2):59-110.
Chicago/Turabian StyleArturo Ramos-Bueno; Universidad Nacional Autónoma De México Posgrado En Geografía; María Perevochtchikova; Heejun Chang; Urbanos Y Ambientales Centro De Estudios Demográficos. 2021. "Socio-spatial analysis of residential water demand in Mexico City." Tecnología y ciencias del agua 12, no. 2: 59-110.
As urban populations continue to grow through the 21st century, more people are projected to be at risk of exposure to climate change-induced extreme events. To investigate the complexity of urban floods, this study applied an interlinked social-ecological-technological systems (SETS) vulnerability framework by developing an urban flood vulnerability index for six US cities. Indicators were selected to reflect and illustrate exposure, sensitivity, and adaptive capacity to flooding for each of the three domains of SETS. We quantified 18 indicators and normalized them by the cities’ 500-yr floodplain area at the census block group level. Clusters of flood vulnerable areas were identified differently by each SETS domain, and some areas were vulnerable to floods in more than one domain. Results are provided to support decision-making for reducing risks to flooding, by considering social, ecological, and technological vulnerability as well as hotspots where multiple sources of vulnerability coexist. The spatially explicit urban SETS flood vulnerability framework can be transferred to other regions facing challenging urban floods and other types of environmental hazards. Mapping SETS flood vulnerability helps to reveal intersections of complex SETS interactions and inform policy-making for building more resilient cities in the face of extreme events and climate change impacts.
Heejun Chang; Arun Pallathadka; Jason Sauer; Nancy B. Grimm; Rae Zimmerman; Chingwen Cheng; David M. Iwaniec; Yeowon Kim; Robert Lloyd; Timon McPhearson; Bernice Rosenzweig; Tiffany Troxler; Claire Welty; Ryan Brenner; Pablo Herreros-Cantis. Assessment of urban flood vulnerability using the social-ecological-technological systems framework in six US cities. Sustainable Cities and Society 2021, 68, 102786 .
AMA StyleHeejun Chang, Arun Pallathadka, Jason Sauer, Nancy B. Grimm, Rae Zimmerman, Chingwen Cheng, David M. Iwaniec, Yeowon Kim, Robert Lloyd, Timon McPhearson, Bernice Rosenzweig, Tiffany Troxler, Claire Welty, Ryan Brenner, Pablo Herreros-Cantis. Assessment of urban flood vulnerability using the social-ecological-technological systems framework in six US cities. Sustainable Cities and Society. 2021; 68 ():102786.
Chicago/Turabian StyleHeejun Chang; Arun Pallathadka; Jason Sauer; Nancy B. Grimm; Rae Zimmerman; Chingwen Cheng; David M. Iwaniec; Yeowon Kim; Robert Lloyd; Timon McPhearson; Bernice Rosenzweig; Tiffany Troxler; Claire Welty; Ryan Brenner; Pablo Herreros-Cantis. 2021. "Assessment of urban flood vulnerability using the social-ecological-technological systems framework in six US cities." Sustainable Cities and Society 68, no. : 102786.
Urban flooding is a major concern in many cities around the world. Together with continuous urbanization, extreme weather events are likely to increase the magnitude and frequency of flood hazards and exposure in populated regions. This article examines the changing pathways of flood risk management (FRM) in Portland, Oregon; Seoul, South Korea; and Tokyo, Japan, which have different histories of land development and flood severity. We used city governance documents to identify how FRM strategies have changed in the study cities. Using a combined framework of social learning with an integrated social–ecological–technological systems (SETS) lens, we show what components of SETS have been emphasized and how FRM strategies have diversified over time. In response to historical flood events, these cities built hard infrastructure such as levees to reduce flood risks. The recent paradigm shift in urban FRM, such as the adoption of socioecological elements in SETS, including floodplain restoration, green infrastructure, and public education, is a response to making cities more resilient or transformative to the anticipated future extreme floods. The pathways that cities have taken and the main emphasis across SETS elements differ by city, however, suggesting that opportunities exist for learning from each city’s experience collectively to tackle global flooding issues.
Heejun Chang; David J. Yu; Samuel A. Markolf; Chang-Yu Hong; Sunyong Eom; Wonsuh Song; Deghyo Bae. Understanding Urban Flood Resilience in the Anthropocene: A Social–Ecological–Technological Systems (SETS) Learning Framework. Annals of the American Association of Geographers 2021, 111, 837 -857.
AMA StyleHeejun Chang, David J. Yu, Samuel A. Markolf, Chang-Yu Hong, Sunyong Eom, Wonsuh Song, Deghyo Bae. Understanding Urban Flood Resilience in the Anthropocene: A Social–Ecological–Technological Systems (SETS) Learning Framework. Annals of the American Association of Geographers. 2021; 111 (3):837-857.
Chicago/Turabian StyleHeejun Chang; David J. Yu; Samuel A. Markolf; Chang-Yu Hong; Sunyong Eom; Wonsuh Song; Deghyo Bae. 2021. "Understanding Urban Flood Resilience in the Anthropocene: A Social–Ecological–Technological Systems (SETS) Learning Framework." Annals of the American Association of Geographers 111, no. 3: 837-857.
While many different watershed management strategies have been implemented to improve water quality, relatively few studies empirically tested the combined effects of different strategies on water quality in relation to land cover changes using long-term empirical data at the sub-basin scale. Using 10 years of total suspended solids (TSS) data, we examined how the conversion of wetland, wetland fragmentation, beaver dams, and Best Management Practices (BMPs) affect wet season TSS concentrations for the 25 monitoring stations in the Tualatin River basin, USA. Geographic information systems, FRAGSTATS, and correlation analysis were used to identify the direction of land cover change, degree of wetland fragmentation, and the strength of the relationship between TSS change and explanatory variables. Improvement in TSS concentrations was tightly coupled with the aggregation of wetlands, presence of beaver dams, particularly during the mid-wet season when flows were highest. Other BMPs effectively reduced TSS concentrations for the early and late-wet seasons when flows were not as high as in the middle wet-season. Aggregated wetlands were more effective for improving water quality than smaller disaggregated wetlands of similar total area when combined with the presence of beaver dams and BMPs. These findings offer important scientific and practical implications for management of urbanizing watersheds that seek to achieve the dual goals of improving environmental quality and land development.
Heejun Chang; Yasuyo Makido; Eugene Foster. Effects of land use change, wetland fragmentation, and best management practices on total suspended solids concentrations in an urbanizing Oregon watershed, USA. Journal of Environmental Management 2021, 282, 111962 .
AMA StyleHeejun Chang, Yasuyo Makido, Eugene Foster. Effects of land use change, wetland fragmentation, and best management practices on total suspended solids concentrations in an urbanizing Oregon watershed, USA. Journal of Environmental Management. 2021; 282 ():111962.
Chicago/Turabian StyleHeejun Chang; Yasuyo Makido; Eugene Foster. 2021. "Effects of land use change, wetland fragmentation, and best management practices on total suspended solids concentrations in an urbanizing Oregon watershed, USA." Journal of Environmental Management 282, no. : 111962.
Floods are important disturbances to urban socio‐eco‐technical systems and their meteorological drivers are projected to increase through the century due to global climate change. Urban flood models are numerical models that have the capability of representing the features of urban ecosystems and the mechanisms of flooding that impact them. They have the potential to play a critical role in flood risk assessment, operational response, and resilience planning, but existing models remain limited in their capability to represent integrated flooding processes in urban areas and provide the credible quantitative information needed to support risk assessment and resilience practice. Research to advance model development, facilitate intensive watershed monitoring for model parameterization and validation, and support collaboration between researchers and practitioners should be prioritized. This will represent a substantial, expensive effort, but will still be of great value as cities are faced with urgent challenges posed by climate change in coming decades.
B. R. Rosenzweig; P. Herreros Cantis; Y. Kim; A. Cohn; K. Grove; J. Brock; J. Yesuf; P. Mistry; C. Welty; T. McPhearson; J. Sauer; H. Chang. The Value of Urban Flood Modeling. Earth's Future 2021, 9, 1 .
AMA StyleB. R. Rosenzweig, P. Herreros Cantis, Y. Kim, A. Cohn, K. Grove, J. Brock, J. Yesuf, P. Mistry, C. Welty, T. McPhearson, J. Sauer, H. Chang. The Value of Urban Flood Modeling. Earth's Future. 2021; 9 (1):1.
Chicago/Turabian StyleB. R. Rosenzweig; P. Herreros Cantis; Y. Kim; A. Cohn; K. Grove; J. Brock; J. Yesuf; P. Mistry; C. Welty; T. McPhearson; J. Sauer; H. Chang. 2021. "The Value of Urban Flood Modeling." Earth's Future 9, no. 1: 1.
Various spatial interrelationships among sampling stations are not well explored in the spatial modeling of water quality literature. This research explores the relationship between water quality and various social, demographic, and topographic factors in an urbanizing watershed of Nepal with a comparison of different connectivity matrices to conceptualize spatial interrelationships. We collected electrical conductivity and dissolved oxygen data from surface water bodies using a handheld probe and used the data to establish relationships with land use, topography, and population density-based explanatory variables at both watershed and 100-m buffer scales. The linear regression model was compared with different eigenvector-based spatial filtering models. These spatial filtering models were constructed using five different spatial conceptualizations based on different graph types generated from the geographic coordinates of the sampling sites. Population density, elevation, and percentage of sand in the watershed and riparian regions are most important in explaining dissolved oxygen concentration and electric conductivity. A human signature as population density and increased sand and gravel cover can be detected in this watershed impacting water quality. Among different graph types compared, the relative graph type provided the highest model strength signifying a stronger upstream-downstream relationship of dissolved oxygen, while k-nearest graph types with four neighbors provided the strongest model performance, indicating the impact of local factors on electrical conductivity. The relationships between socio-environmental factors and water quality and their spatial interrelationships identified in this work shed light on the source, mobilization, and transport of dissolved oxygen and electrical conductivity and can assist the water quality management endeavor.
Janardan Mainali; Heejun Chang. Environmental and spatial factors affecting surface water quality in a Himalayan watershed, Central Nepal. Environmental and Sustainability Indicators 2020, 9, 100096 .
AMA StyleJanardan Mainali, Heejun Chang. Environmental and spatial factors affecting surface water quality in a Himalayan watershed, Central Nepal. Environmental and Sustainability Indicators. 2020; 9 ():100096.
Chicago/Turabian StyleJanardan Mainali; Heejun Chang. 2020. "Environmental and spatial factors affecting surface water quality in a Himalayan watershed, Central Nepal." Environmental and Sustainability Indicators 9, no. : 100096.
We examined the performance of ecoroofs with different substrate depths (75 mm, 125 mm) as well as a conventional roof using rainfall and runoff data collected between 2014 and 2017 in Portland, Oregon, USA. The two ecoroof plots exhibited similar effectiveness in retaining storm runoff across all storm size categories, and both ecoroofs retained the most stormwater during small storms. Retention ratio (RR) was highest during the dry season and the lowest in the early and middle of the wet season. RR was also positively associated with antecedent dry weather period (ADWP) with significantly higher retention when ADWP was longer than 3 days. Together, event storm size and ADWP explain approximately 50% of RR variation in middle and late-wet seasons. Overall, these findings indicate that environmental parameters such as storm frequency and size had a greater influence on greenroof performance than an additional 50 mm of substrate.
Heejun Chang; Ashley M. Baker; Olyssa Starry; Junjie Chen. Seasonal variation in hydrologic performance of ecoroofs of multiple depths– a case study in Portland, Oregon, USA. Urban Water Journal 2020, 18, 128 -135.
AMA StyleHeejun Chang, Ashley M. Baker, Olyssa Starry, Junjie Chen. Seasonal variation in hydrologic performance of ecoroofs of multiple depths– a case study in Portland, Oregon, USA. Urban Water Journal. 2020; 18 (2):128-135.
Chicago/Turabian StyleHeejun Chang; Ashley M. Baker; Olyssa Starry; Junjie Chen. 2020. "Seasonal variation in hydrologic performance of ecoroofs of multiple depths– a case study in Portland, Oregon, USA." Urban Water Journal 18, no. 2: 128-135.
Assuring healthy streams in the urban environment is a major goal for restoration scientists, urban planners, and city practitioners around the globe. In South Korea, many urban stream restoration efforts are designed to provide safe water to society and enhance ecological functions. We examined the extent to which the individual interests and different values of multiple stakeholders were considered in previous decision-making in two urban stream restoration projects. The relevant data on stream restoration were collected through the nominal group technique (NGT) and the analytic hierarchy process (AHP) for the two stream cases of a populated inland area and a coastal region in South Korea. The AHP results provide information about the comparative weights of the values of ecological restoration (priority score: 0.487), social restoration (priority score: 0.231), and landscape revitalization (priority score: 0.279) of the Ahn-Yang stream and ecological restoration (priority score: 0.527), social restoration (priority score: 0.182), and landscape revitalization (priority score: 0.290) of the Sahn-Jee stream. The stakeholders of the populated metropolitan area had a relatively high awareness of their role in environmental restoration, thus it was natural for them to place a high value on social restoration.
Chang-Yu Hong; Eun-Sung Chung; Heejun Chang. The Right to Urban Streams: Quantitative Comparisons of Stakeholder Perceptions in Defining Adaptive Stream Restoration. Sustainability 2020, 12, 9500 .
AMA StyleChang-Yu Hong, Eun-Sung Chung, Heejun Chang. The Right to Urban Streams: Quantitative Comparisons of Stakeholder Perceptions in Defining Adaptive Stream Restoration. Sustainability. 2020; 12 (22):9500.
Chicago/Turabian StyleChang-Yu Hong; Eun-Sung Chung; Heejun Chang. 2020. "The Right to Urban Streams: Quantitative Comparisons of Stakeholder Perceptions in Defining Adaptive Stream Restoration." Sustainability 12, no. 22: 9500.
Gunnar Johnson; Heejun Chang; Andrew Fountain. Supplementary material to "Rock glaciers of the contiguous United States: GIS inventory and spatial distribution patterns". 2020, 1 .
AMA StyleGunnar Johnson, Heejun Chang, Andrew Fountain. Supplementary material to "Rock glaciers of the contiguous United States: GIS inventory and spatial distribution patterns". . 2020; ():1.
Chicago/Turabian StyleGunnar Johnson; Heejun Chang; Andrew Fountain. 2020. "Supplementary material to "Rock glaciers of the contiguous United States: GIS inventory and spatial distribution patterns"." , no. : 1.
Continental-scale inventories of glaciers are available, but no analogous rock glacier inventories exist. We present the Portland State University Rock Glacier Inventory (n = 10,343) for the contiguous United States, derived from the manual classification of remote sensing imagery (Johnson 2020, https://doi.pangaea.de/10.1594/PANGAEA.918585). Individually, these rock glaciers are found across widely disparate montane environments, but their overall distribution unambiguously favors relatively high, arid mountain ranges with sparse vegetation. While at least one rock glacier is identified in each of the 11 westernmost states, nearly 88 % are found in just five states: Colorado (n = 3889), Montana (n = 1813), Idaho (n = 1689), Wyoming (n = 850), and Utah (n = 834). Mean rock glacier area is estimated at 0.10 km2, with cumulative rock glacier area totaling 1008.91 km2. Rock glaciers are assigned to a three-tier classification system based on area thresholds and surface characteristics known to correlate with downslope movement. Class 1 features (n = 7052, average area = 0.12 km2) appear to be highly active, Class 2 features (n = 2416, average area = 0.05 km2) appear to be intermediately active and Class 3 features (n = 875, average area = 0.04 km2) appear to be minimally active. This geospatial inventory will allow past rock glacier research findings to be spatially extrapolated, help facilitate further rock glacier research by identifying field study sites, and serve as a valuable training set for the development of automated rock glacier identification and classification methods applicable to other large regional studies.
Gunnar Johnson; Heejun Chang; Andrew Fountain. Rock glaciers of the contiguous United States: GIS inventory and spatial distribution patterns. 2020, 2020, 1 -26.
AMA StyleGunnar Johnson, Heejun Chang, Andrew Fountain. Rock glaciers of the contiguous United States: GIS inventory and spatial distribution patterns. . 2020; 2020 ():1-26.
Chicago/Turabian StyleGunnar Johnson; Heejun Chang; Andrew Fountain. 2020. "Rock glaciers of the contiguous United States: GIS inventory and spatial distribution patterns." 2020, no. : 1-26.
This research examines how individual preferences for the major functions of stream restoration processes are associated with flood prevention and risk mitigation in Johnson Creek of Portland, Oregon, USA. We first reviewed a set of results from an analytical hierarchy process (AHP) model to rank the major stream restoration functions and compared citizens' preferences for “flood prevention” using ordinary least squares regression. Our results show that the perceptions and interests of citizens may be centred on the inconvenience of everyday life arising from the previous flood events. Residents in the highly urbanized downstream regions showed a higher sensitivity to flooding than those living in the upper regions of the watershed. Community participation and annual incomes are positively related to flood risk perception in more developed downstream regions, while ecological or development goals associated with property protection are positively associated with higher flood risk perception in the less developed upper regions. Our findings of citizen perceptions can be adopted to help local government leaders and households mitigate flood risk while also achieving multiple benefits from stream restoration projects.
Chang‐Yu Hong; Heejun Chang. Residents' perception of flood risk and urban stream restoration using multi‐criteria decision analysis. River Research and Applications 2020, 36, 2078 -2088.
AMA StyleChang‐Yu Hong, Heejun Chang. Residents' perception of flood risk and urban stream restoration using multi‐criteria decision analysis. River Research and Applications. 2020; 36 (10):2078-2088.
Chicago/Turabian StyleChang‐Yu Hong; Heejun Chang. 2020. "Residents' perception of flood risk and urban stream restoration using multi‐criteria decision analysis." River Research and Applications 36, no. 10: 2078-2088.
To understand the spatial–temporal pattern of climate and land cover (CLC) change effects on hydrology, we used three land cover change (LCC) coupled scenarios to estimate the changes in streamflow metrics in the Clackamas River Watershed in Oregon for the 2050s (2040–2069) and the 2080s (2070–2099). Coupled scenarios, which were split into individual and combined simulations such as climate change (CC), LCC, CLC change, and daily streamflow were simulated in the Soil and Water Assessment Tool. The interannual variability of streamflow was higher in the lower urbanized area than the upper forested region. The watershed runoff was projected to be more sensitive to CC than LCC. Under the CLC scenario, the top 10% peak flow and the 7-day low flow are expected to increase (2–19%) and decrease (+9 to −20 cm s), respectively, in both future periods. The center timing of runoff in the year is projected to shift 2–3 weeks earlier in response to warming temperature and more winter precipitation falling as rain. High streamflow variability in our findings suggests that uncertainties can stem from both climate models and hydrologic model parameters, calling for more adaptive water resource management in the watershed.
Junjie Chen; Heejun Chang. Relative impacts of climate change and land cover change on streamflow using SWAT in the Clackamas River Watershed, USA. Journal of Water and Climate Change 2020, 12, 1454 -1470.
AMA StyleJunjie Chen, Heejun Chang. Relative impacts of climate change and land cover change on streamflow using SWAT in the Clackamas River Watershed, USA. Journal of Water and Climate Change. 2020; 12 (5):1454-1470.
Chicago/Turabian StyleJunjie Chen; Heejun Chang. 2020. "Relative impacts of climate change and land cover change on streamflow using SWAT in the Clackamas River Watershed, USA." Journal of Water and Climate Change 12, no. 5: 1454-1470.
Over the next century, model projections suggest that river run‑off in the Pacific Northwest will increase during the winter season and that sea-level rise (SLR) may exceed a meter. To investigate the resulting changes in flood hazard, we numerically model the February 1996 and January 1923 floods (the largest and third-largest Willamette River floods since 1900) under present and potential future run-off and sea level scenarios. First, we reproduce the actual February 1996 flood to within a root-mean-square error of 0.05 m (N = 7) for peak water levels. Next, we run scenarios in which three SLR scenarios (0, 0.6, and 1.5 m) are combined with two river run-off scenarios (0% and 10% run-off increase). Then the slightly larger 1923 flood scenario is run, but with modern (higher than historical) Columbia River flow. The results indicate that a 10% increase in river run-off increased the1996 flood magnitude by 0.78 m, while 1923 flow increases flood magnitude by 0.82 m. Overall, the type and magnitude of future flood hazards vary with reach. The Portland/Vancouver Metropolitan area is most sensitive to changes in run-off, with a smaller change of ~0.2–0.26 m per meter of SLR. By contrast, coastal regions are quite sensitive to amplified sea level and exhibit nonlinear responses based on changes to river slope and tides. Between the fluvial region and the estuary, a region of compound flood hazard exists that is sensitive to changes in river discharge, sea level, tides, and storm surge.
Lumas T. Helaire; Stefan A. Talke; David A. Jay; Heejun Chang. Present and Future Flood Hazard in the Lower Columbia River Estuary: Changing Flood Hazards in the Portland‐Vancouver Metropolitan Area. Journal of Geophysical Research: Oceans 2020, 125, 1 .
AMA StyleLumas T. Helaire, Stefan A. Talke, David A. Jay, Heejun Chang. Present and Future Flood Hazard in the Lower Columbia River Estuary: Changing Flood Hazards in the Portland‐Vancouver Metropolitan Area. Journal of Geophysical Research: Oceans. 2020; 125 (7):1.
Chicago/Turabian StyleLumas T. Helaire; Stefan A. Talke; David A. Jay; Heejun Chang. 2020. "Present and Future Flood Hazard in the Lower Columbia River Estuary: Changing Flood Hazards in the Portland‐Vancouver Metropolitan Area." Journal of Geophysical Research: Oceans 125, no. 7: 1.
This study addresses how regional changes to precipitation may be identified by exploring the effect of temporal resolution on trend detection. Climate indices that summarize precipitation characteristics are used with Mann–Kendall monotonic testing to investigate precipitation trends in Portland, Oregon (OR) from 1977 to 2016. Observational records from rain gages are compared with downscaled global climate models to determine trends for the historic (1977–2005) and future (2006–2100) periods. Standard indices created by the Expert Team on Climate Change Detection and Indices (ETCCDI) are deployed. ETCCDI indices that summarize conditions at the annual level are generated alongside a limited number of ETCCDI indices summarized at the monthly level. For the future climate, the indices summarized at the annual level demonstrate trends indicative of an intensifying hydrologic cycle. The historical record depicted by annual indices does not show trends. The historical record is viewed differently by changing the indices to monthly summaries, which causes trend detection to increase and hallmark indicators of an intensifying hydrologic cycle to become apparent.
Alexis Kirsten Cooley; Heejun Chang. Detecting change in precipitation indices using observed (1977–2016) and modeled future climate data in Portland, Oregon, USA. Journal of Water and Climate Change 2020, 12, 1135 -1153.
AMA StyleAlexis Kirsten Cooley, Heejun Chang. Detecting change in precipitation indices using observed (1977–2016) and modeled future climate data in Portland, Oregon, USA. Journal of Water and Climate Change. 2020; 12 (4):1135-1153.
Chicago/Turabian StyleAlexis Kirsten Cooley; Heejun Chang. 2020. "Detecting change in precipitation indices using observed (1977–2016) and modeled future climate data in Portland, Oregon, USA." Journal of Water and Climate Change 12, no. 4: 1135-1153.
This paper reviews socio-hydrology and hydrosocial research, finding a sophisticated relationship with emergent syntheses. We examined 419 papers by topic, region of study, theories implemented, journal, and year published to ascertain trends in both subfields. We found important overlap and considerable difference between subfields. Whereas hydrosocial research took years to develop, socio-hydrology commenced with an inaugural paper in 2012. While the former focuses on power and scale in studying water demand, the latter concentrates on practical responses to climate extremes. Hydrosocial research usually relies on qualitative methods, and socio-hydrology research the quantitative. In the geographic regions where the former does not focus, the latter does. The former often relies on post-structuralist theory, whereas the latter uses positivist approaches. Our review concludes that socio-hydrology and hydrosocial research exist in a complex epistemological relationship, offering fertile grounds for lively discussions from which both will continue to benefit.
Alexander Ross; Heejun Chang. Socio-hydrology with hydrosocial theory: two sides of the same coin? Hydrological Sciences Journal 2020, 65, 1443 -1457.
AMA StyleAlexander Ross, Heejun Chang. Socio-hydrology with hydrosocial theory: two sides of the same coin? Hydrological Sciences Journal. 2020; 65 (9):1443-1457.
Chicago/Turabian StyleAlexander Ross; Heejun Chang. 2020. "Socio-hydrology with hydrosocial theory: two sides of the same coin?" Hydrological Sciences Journal 65, no. 9: 1443-1457.
In the original publication of the article, two of the contributors’ names (Darrell Brown, Kim Heavener) were missing in the acknowledgement section. The correct acknowledgement is provided below.
Heejun Chang; Elise F. Granek; David Ervin; Alan Yeakley; Veronica Dujon; Vivek Shandas. Correction to: A community‑engaged approach to transdisciplinary doctoral training in urban ecosystem services. Sustainability Science 2020, 15, 1253 -1253.
AMA StyleHeejun Chang, Elise F. Granek, David Ervin, Alan Yeakley, Veronica Dujon, Vivek Shandas. Correction to: A community‑engaged approach to transdisciplinary doctoral training in urban ecosystem services. Sustainability Science. 2020; 15 (4):1253-1253.
Chicago/Turabian StyleHeejun Chang; Elise F. Granek; David Ervin; Alan Yeakley; Veronica Dujon; Vivek Shandas. 2020. "Correction to: A community‑engaged approach to transdisciplinary doctoral training in urban ecosystem services." Sustainability Science 15, no. 4: 1253-1253.
Community-based projects with inclusive stakeholder engagement are increasingly important to achieve robust outcomes in the science and management of ‘wicked’ urban ecosystem service challenges. We summarize lessons learned from a transdisciplinary, team-based doctoral education program that engaged students in research on such multi-stakeholder, complex problems. The key lessons are (a) problem-based projects foster active student engagement and accelerate transdisciplinary analysis, (b) problems addressing more acute interventions by public or private organizations enable learning by clearly delineating the issues and revealing the goals and perspectives of varied stakeholders, (c) successful projects that address wicked problems require that transdisciplinary teams begin from inception to robustly frame research questions with multiple lenses and choose appropriate theories and methods to implement projects, (d) regular stakeholder engagement leads to mutually meaningful project outcomes that advance scholarly frontiers for university researchers and provide relevant solutions for community partners, and (e) university administrative investment in program faculty, students, and staff and flexibility to reward innovative collaborations across disciplinary boundaries are keys to facilitate success in transdisciplinary education. Our lessons provide guidance both for addressing wicked problems through research projects in general and for formulating transdisciplinary training approaches for graduate education.
Heejun Chang; Elise F. Granek; David Ervin; Alan Yeakley; Veronica Dujon; Vivek Shandas. A community-engaged approach to transdisciplinary doctoral training in urban ecosystem services. Sustainability Science 2020, 15, 699 -715.
AMA StyleHeejun Chang, Elise F. Granek, David Ervin, Alan Yeakley, Veronica Dujon, Vivek Shandas. A community-engaged approach to transdisciplinary doctoral training in urban ecosystem services. Sustainability Science. 2020; 15 (3):699-715.
Chicago/Turabian StyleHeejun Chang; Elise F. Granek; David Ervin; Alan Yeakley; Veronica Dujon; Vivek Shandas. 2020. "A community-engaged approach to transdisciplinary doctoral training in urban ecosystem services." Sustainability Science 15, no. 3: 699-715.
When examining the relationship between landscape characteristics and water quality, most previous studies did not pay enough attention to the spatial aspects of landscape characteristics and water quality sampling stations. We analyzed the spatial pattern of total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD), and suspended solids (SS) in the Han River basin of South Korea to explore the role of different distance considerations and spatial statistical approaches to explaining the variation in water quality. Five-year (2012 through 2016) seasonal averages of those water quality attributes were used in the analysis as the response variables, while explanatory variables like land cover, elevation, slope, and hydrologic soil groups were subjected to different weighting treatments based on distance and flow accumulation. Moran's Eigenvector-based spatial filters were used to consider spatial relations among water quality sampling sites and were used in regression models. Distinct spatial patterns of seasonal water quality exist, with the highest concentrations of TN, TP, COD, and SS in downstream urban areas and the lowest concentrations in upstream forest areas. TN concentrations are higher in dry winter than the wet summer season, while SS concentrations are higher in wet summer than the dry season. Spatial models substantially improved the model fit compared to aspatial models. The flow accumulation-based models performed best when the spatial filters were not used, but all models performed similarly when spatial filters were used. The distance weighting approaches were instrumental in understanding watershed level processes affecting source, mobilization, and delivery of physicochemical parameters that flow into the river water. We conclude that a consideration of the spatial aspects of sampling sites is as important as accounting for different distances and hydrological processes in modeling water quality.
Janardan Mainali; Heejun Chang. Putting space into modeling landscape and water quality relationships in the Han River basin, South Korea. Computers, Environment and Urban Systems 2020, 81, 101461 .
AMA StyleJanardan Mainali, Heejun Chang. Putting space into modeling landscape and water quality relationships in the Han River basin, South Korea. Computers, Environment and Urban Systems. 2020; 81 ():101461.
Chicago/Turabian StyleJanardan Mainali; Heejun Chang. 2020. "Putting space into modeling landscape and water quality relationships in the Han River basin, South Korea." Computers, Environment and Urban Systems 81, no. : 101461.