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• 1. [Article] Using Spatially Explicit Indicators to Investigate Watershed Characteristics and stream temperature relationships

  We generate a series of novel indicators of spatially explicit watershed permeability and runoff characteristics to examine the relationship between land cover and water temperature parameters in a rapidly ...

  Citation × Citation Citation Abstract Copy Title: Using Spatially Explicit Indicators to Investigate Watershed Characteristics and stream temperature relationships Author: Grabowski, Zbigniew J., Watson, Eric, Chang, Heejun Year: 2016 We generate a series of novel indicators of spatially explicit watershed permeability and runoff characteristics to examine the relationship between land cover and water temperature parameters in a rapidly urbanizing watershed. Our framework provides a readily adaptable method to examine the thermal sensitivity of streams based upon the underlying geomorphological and surface characteristics of drainage basins. Using four model groups each using a different landscape characteristic weighting scheme (Model Group 1: areal averages; Model Group 2: inverse distance by total flow length; Model Group 3: overland distance to stream network and distance squared; Model Group 4: proportional flow accumulation), we examined the predictive capacity of 19 variables, including combinations of simplified land cover, elevation, slope, and flow accumulation, on five stream thermal properties: seven day moving average of daily minimum and maximum, seasonal mean temperature, a novel metric of thermal 'flashiness', and total days with maximum temperature exceeding 17.8°C. We find that the use of spatially explicit landscape indicators combining watershed processes improves the performance of regressions for predicting a number of ecologically relevant stream temperature variables. Improved indicators of watershed condition lend themselves for rapid investigation of the relationship between stream thermal conditions and landscape characteristics in watersheds modified by human land uses, ultimately providing a more hydrologically meaningful indicator for the impacts of landscape change. Title: Using Spatially Explicit Indicators to Investigate Watershed Characteristics and stream temperature relationships Author: Grabowski, Zbigniew J., Watson, Eric, Chang, Heejun Year: 2016 We generate a series of novel indicators of spatially explicit watershed permeability and runoff characteristics to examine the relationship between land cover and water temperature parameters in a rapidly urbanizing watershed. Our framework provides a readily adaptable method to examine the thermal sensitivity of streams based upon the underlying geomorphological and surface characteristics of drainage basins. Using four model groups each using a different landscape characteristic weighting scheme (Model Group 1: areal averages; Model Group 2: inverse distance by total flow length; Model Group 3: overland distance to stream network and distance squared; Model Group 4: proportional flow accumulation), we examined the predictive capacity of 19 variables, including combinations of simplified land cover, elevation, slope, and flow accumulation, on five stream thermal properties: seven day moving average of daily minimum and maximum, seasonal mean temperature, a novel metric of thermal 'flashiness', and total days with maximum temperature exceeding 17.8°C. We find that the use of spatially explicit landscape indicators combining watershed processes improves the performance of regressions for predicting a number of ecologically relevant stream temperature variables. Improved indicators of watershed condition lend themselves for rapid investigation of the relationship between stream thermal conditions and landscape characteristics in watersheds modified by human land uses, ultimately providing a more hydrologically meaningful indicator for the impacts of landscape change. Close

• 2. [Article] Determinants of Single Family Residential Water Use Across Scales in Four Western US Cities

  A growing body of literature examines urban water sustainability with increasing evidence that locally-based physical and social spatial interactions contribute to water use. These studies however are ...

  Citation × Citation Citation Abstract Copy Title: Determinants of Single Family Residential Water Use Across Scales in Four Western US Cities Author: Chang, Heejun, Bonnette, Matthew Ryan, Stoker, Philip, Crow-Miller, Britt, Wentz, Elizabeth A, Year: 2017 A growing body of literature examines urban water sustainability with increasing evidence that locally-based physical and social spatial interactions contribute to water use. These studies however are based on single-city analysis and often fail to consider whether these interactions occur more generally. We examine a multi-city comparison using a common set of spatially-explicit water, socioeconomic, and biophysical data. We investigate the relative importance of variables for explaining the variations of single family residential (SFR) water uses at Census Block Group (CBG) and Census Tract (CT) scales in four representative western US cities - Austin, Phoenix, Portland, and Salt Lake City, - which cover a wide range of climate and development density. We used both ordinary least squares regression and spatial error regression models to identify the influence of spatial dependence on water use patterns. Our results show that older downtown areas show lower water use than newer suburban areas in all four cities. Tax assessed value and building age are the main determinants of SFR water use across the four cities regardless of the scale. Impervious surface area becomes an important variable for summer water use in all cities, and it is important in all seasons for arid environments such as Phoenix. CT level analysis shows better model predictability than CBG analysis. In all cities, seasons, and spatial scales, spatial error regression models better explain the variations of SFR water use. Such a spatially-varying relationship of urban water consumption provides additional evidence for the need to integrate urban land use planning and municipal water planning. (C) 2017 Elsevier B.V. All rights reserved. Title: Determinants of Single Family Residential Water Use Across Scales in Four Western US Cities Author: Chang, Heejun, Bonnette, Matthew Ryan, Stoker, Philip, Crow-Miller, Britt, Wentz, Elizabeth A, Year: 2017 A growing body of literature examines urban water sustainability with increasing evidence that locally-based physical and social spatial interactions contribute to water use. These studies however are based on single-city analysis and often fail to consider whether these interactions occur more generally. We examine a multi-city comparison using a common set of spatially-explicit water, socioeconomic, and biophysical data. We investigate the relative importance of variables for explaining the variations of single family residential (SFR) water uses at Census Block Group (CBG) and Census Tract (CT) scales in four representative western US cities - Austin, Phoenix, Portland, and Salt Lake City, - which cover a wide range of climate and development density. We used both ordinary least squares regression and spatial error regression models to identify the influence of spatial dependence on water use patterns. Our results show that older downtown areas show lower water use than newer suburban areas in all four cities. Tax assessed value and building age are the main determinants of SFR water use across the four cities regardless of the scale. Impervious surface area becomes an important variable for summer water use in all cities, and it is important in all seasons for arid environments such as Phoenix. CT level analysis shows better model predictability than CBG analysis. In all cities, seasons, and spatial scales, spatial error regression models better explain the variations of SFR water use. Such a spatially-varying relationship of urban water consumption provides additional evidence for the need to integrate urban land use planning and municipal water planning. (C) 2017 Elsevier B.V. All rights reserved. Close

• 3. [Article] Facilitating Collaborative Urban Water Management Through University-Utility Cooperation

  In the face of intensifying stresses such as climate change, rapid urban population growth, land use change, and public concern with rates and use restrictions, water management is becoming increasingly ...

  Citation × Citation Citation Abstract Copy Title: Facilitating Collaborative Urban Water Management Through University-Utility Cooperation Author: Crow-Miller, Britt, Chang, Heejun, Stoker, Philip, Wentz, Elizabeth A, Year: 2016 In the face of intensifying stresses such as climate change, rapid urban population growth, land use change, and public concern with rates and use restrictions, water management is becoming increasingly complex in the cities of the American West. One strategy to improve water management practices in this changing social-ecological context is to develop collaborative relationships that facilitate the engagement of multiple stakeholders at multiple scales. At the local level, one important but frequently underdeveloped collaborative link is that between university researchers and water utilities, who together occupy the interstitial space between science and decision-making, while at the same time interfacing with water users. Based on workshop data, a pilot survey, and interviews with representative water managers and university researchers from cities across the American West, we identify a number of barriers to establishing collaborative platforms from which utilities and university researchers can effectively work together to tackle challenges around sustainable urban water management in the twenty-first century. We make suggestions for overcoming these barriers and argue that developing an integrated model for university-utility collaborations is a critical area on which we must focus our collective attention if sustainable urban water management is to be achieved. Title: Facilitating Collaborative Urban Water Management Through University-Utility Cooperation Author: Crow-Miller, Britt, Chang, Heejun, Stoker, Philip, Wentz, Elizabeth A, Year: 2016 In the face of intensifying stresses such as climate change, rapid urban population growth, land use change, and public concern with rates and use restrictions, water management is becoming increasingly complex in the cities of the American West. One strategy to improve water management practices in this changing social-ecological context is to develop collaborative relationships that facilitate the engagement of multiple stakeholders at multiple scales. At the local level, one important but frequently underdeveloped collaborative link is that between university researchers and water utilities, who together occupy the interstitial space between science and decision-making, while at the same time interfacing with water users. Based on workshop data, a pilot survey, and interviews with representative water managers and university researchers from cities across the American West, we identify a number of barriers to establishing collaborative platforms from which utilities and university researchers can effectively work together to tackle challenges around sustainable urban water management in the twenty-first century. We make suggestions for overcoming these barriers and argue that developing an integrated model for university-utility collaborations is a critical area on which we must focus our collective attention if sustainable urban water management is to be achieved. Close

• 4. [Article] Analysis of Long-Term Climate Change on Per Capita Water Demand in Urban Versus Suburban Areas in the Portland Metropolitan Area, USA

  We investigated the impacts of long-term climate variability and change on per capita water demand in urban and suburban service areas that have different degrees of development density in the Portland ...

  Citation × Citation Citation Abstract Copy Title: Analysis of Long-Term Climate Change on Per Capita Water Demand in Urban Versus Suburban Areas in the Portland Metropolitan Area, USA Author: Parandvash, G. Hossein, Chang, Heejun Year: 2016 We investigated the impacts of long-term climate variability and change on per capita water demand in urban and suburban service areas that have different degrees of development density in the Portland metropolitan area, USA. Together with historical daily weather and water production data, socioeconomic data such as population and unemployment rate were used to estimate daily per capita water demand in the two service areas. The structural time series regression model results show that the sensitivity of per capita water demand to both weather and unemployment rate variables is higher in suburban areas than in urban areas. This is associated with relatively higher proportional demand by the residential sector in the suburban area. The estimated coefficients of the historical demand model were used to project the mid-21st century (2035–2064) per capita water demand under three climate change scenarios that represent high (HadGEM2-ES), medium (MIROC5), and low (GFDL) climate changes. Without climate adaptation, compared to the historical period between 1983 and 2012, per capita water demand is projected to increase by 10.6% in the 2035–2064 period under the HadGEM2-ES in suburban areas, while per capita demand is projected to increase by 4.8% under the same scenario in urban areas. Our findings have implications for future urban water resource management and land use planning in the context of climate variability and change. A tight integration between water resource management and urban planning is needed for preparing for climate adaptation in municipal water planning and management. Title: Analysis of Long-Term Climate Change on Per Capita Water Demand in Urban Versus Suburban Areas in the Portland Metropolitan Area, USA Author: Parandvash, G. Hossein, Chang, Heejun Year: 2016 We investigated the impacts of long-term climate variability and change on per capita water demand in urban and suburban service areas that have different degrees of development density in the Portland metropolitan area, USA. Together with historical daily weather and water production data, socioeconomic data such as population and unemployment rate were used to estimate daily per capita water demand in the two service areas. The structural time series regression model results show that the sensitivity of per capita water demand to both weather and unemployment rate variables is higher in suburban areas than in urban areas. This is associated with relatively higher proportional demand by the residential sector in the suburban area. The estimated coefficients of the historical demand model were used to project the mid-21st century (2035–2064) per capita water demand under three climate change scenarios that represent high (HadGEM2-ES), medium (MIROC5), and low (GFDL) climate changes. Without climate adaptation, compared to the historical period between 1983 and 2012, per capita water demand is projected to increase by 10.6% in the 2035–2064 period under the HadGEM2-ES in suburban areas, while per capita demand is projected to increase by 4.8% under the same scenario in urban areas. Our findings have implications for future urban water resource management and land use planning in the context of climate variability and change. A tight integration between water resource management and urban planning is needed for preparing for climate adaptation in municipal water planning and management. Close