Patricia Gober

University of Saskatchewan, Saskatoon, Saskatchewan, Canada

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Publications (63)97.12 Total impact

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    ABSTRACT: Using a system dynamics approach, an integrated water resources system model is developed for scenario analysis of the Saskatchewan portion of the transboundary Saskatchewan River Basin in western Canada. The water resources component is constructed by emulating an existing Water Resources Management Model. Enhancements include an irrigation sub-model to estimate dynamic irrigation demand, including alternative potential evapotranspiration estimates, and an economic sub-model to estimate the value of water use for various sectors of the economy. Results reveal that the water resources system in Saskatchewan becomes increasingly sensitive to the selection of evapotranspiration algorithm as the irrigation area increases, due to competition between hydropower and agriculture. Preliminary results suggest that irrigation expansion would decrease hydropower production, but might increase the total direct economic benefits to Saskatchewan. However, indirect costs include reduction in lake levels and river flows.
    Environmental Modelling and Software 08/2014; 58:12–26. · 3.48 Impact Factor
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    ABSTRACT: Central to the Smart Growth movement is that compact development reduces vehicle miles traveled, carbon emissions, and water use. Empirical efforts to evaluate compact development have examined residential densities but have not distinguished decreasing lot sizes from multifamily apartments as mechanisms for compact development. Efforts to link design features to water use have emphasized single-family at the expense of multifamily housing. This study isolates the determinants of water use in large (more than fifty units) apartment complexes in the city of Tempe, Arizona. In July 2007, per bedroom water use increased with pool area, dishwashers, and in-unit laundry facilities. We are able to explain nearly 50 percent of the variation in water demand with these variables. These results inform public policy for reducing water use in multifamily housing structures, suggesting strategies to construct and market “green” apartment units.
    The Professional Geographer 01/2014; 66(3). · 1.41 Impact Factor
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    ABSTRACT: The connection between scientific knowledge and environmental policy is enhanced through boundary organizations and objects that are perceived to be credible, salient, and legitimate. In this study, water resource decision-makers evaluated the knowledge embedded in WaterSim, an interactive simulation model of water supply and demand presented in an immersive decision theater. Content analysis of individual responses demonstrated that stakeholders were fairly critical of the model's validity, relevance, and bias. Differing perspectives reveal tradeoffs in achieving credible, salient, and legitimate boundary objects, along with the need for iterative processes that engage them in the co-production of knowledge and action. FFECTIVE ENVIRONMENTAL POLICY and decision-making requires linking knowl-edge and action through coordination and communication between individual and institutional actors spanning scientific and political spheres. Sev-eral scholars have examined these intersecting spheres in an attempt to understand and enhance the connection between scientific knowledge production and political decision-making with respect to the natural environment (Cash et al., 2003; Guston, 1999; Jasanoff, 1990; Jones et al., 1999; Lemos and Morehouse, 2005; White et al., 2008). A number of key lessons have been identified from this work. First, the way issues are framed can affect how knowledge and action are linked, how the decision space is defined, which actors are empowered or disenfranchised, and ultimately what outcomes re-sult (Hall and White, 2008). Second, the quality of the linkage between knowledge and action is related to stakeholder perceptions of knowledge systems, in terms of credibility, salience, and legitimacy (Cash et al., 2003). Third, research highlights the signifi-cance of boundary-spanning processes, organiza-tions, and outcomes that exist at the frontiers of multiple social worlds and facilitate interaction, communication, and stabilization (Cash et al., 2003; Guston, 1999; Miller, 2001; White et al., 2008). Taking these lessons as a starting point, in this article we present an empirical study of stake-holders' assessment of the credibility, salience, and legitimacy of a particular boundary object in environmental decision-making. By evaluating the E
    Science and Public Policy 12/2013; · 0.98 Impact Factor
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    ABSTRACT: Research on how heat impacts human health has increased as climate change threatens to raise temperatures to new extremes. Excessive heat exposure increases death rates, as well as rates of nonfatal, adverse health outcomes. This study used the negative binomial regression model to examine the relationship between daily maximum temperature, heat index, and heat-related emergency calls in Phoenix, Arizona and Chicago, Illinois, from 2003 to 2006. Using model results, we estimated call volumes in a warmer climate, with temperature increase from 1 to 5.5 °C. We found that: (1) heat-stress calls increase sharply when the temperature exceeds about 35 °C in Chicago and in 45 °C Phoenix; (2) warmer climate could seriously threaten human health and existing emergency response system in Chicago more than in Phoenix. Policies to reduce heat impacts in Phoenix should focus on reducing prolonged heat exposure, while Chicago should build a strong early-warning system for extreme heat events and provide sufficient resources and infrastructure to mitigate heat stress during those events.
    Urban Climate. 10/2013; 5:1–18.
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    ABSTRACT: The coupled processes of climate change and urbanization pose challenges for water resource management in cities worldwide. Comparing the vulnerabilities of water systems in Phoenix, Arizona and Portland, Oregon, this paper examines (1) exposures to these stressors, (2) sensitivities to the associated impacts, and (3) adaptive capacities for responding to realized or anticipated impacts. Based on a case study and survey-based approach, common points of vulnerability include: rising exposures to drier, warmer summers, and suburban growth; increasing sensitivities based on demand hardening; and limited capacities due to institutional and pro-growth pressures. Yet each region also exhibits unique vulnerabilities. Comparatively, Portland shows: amplified exposures to seasonal climatic extremes, heightened sensitivity based on less diversified municipal water sources and policies that favor more trees and other irrigated vegetation, and diminished adaptive capacities because of limited attention to demand management and climate planning for water resources. Phoenix exhibits elevated exposure from rapid growth, heightened sensitivities due to high water demands and widespread increases in residential and commercial uses, and limited adaptive capacities due to weak land use planning and "smart growth" strategies. Unique points of vulnerability suggest pathways for adapting to urban-environmental change, whether through water management or land planning. Greater coordination between the land and water sectors would substantially reduce vulnerabilities in the study regions and beyond.
    Environmental Management 05/2013; · 1.65 Impact Factor
  • Patricia Gober
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    ABSTRACT: Discriminant analysis was used to investigate the empirical underpinnings of the labels, "Sunbelt" and "Frostbelt." Nine study variables were chosen to represent structural, economic, and population characteristics in 158 SMSAs with 1980 populations over 200,000. The results show that SMSAs in the Sunbelt have lower densities; they house larger minority populations who are less likely to participate in the political process; and their economies are less oriented to manufacturing. In terms of the regional convergence-uneven development debate, results favor the uneven development thesis. The fact that Sunbelt metropolitan areas house populations that are different from their Frostbelt counterparts and perform different social roles and functions in the national space economy suggests they represent a new form of urban development rather than a manifestation of heretofore lagging regions converging with traditional centers of development.
    Urban Geography 05/2013; 5(2):130-145. · 1.36 Impact Factor
  • Howard Wheater, Patricia Gober
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    ABSTRACT: In this paper, we discuss the multiple dimensions of water security and define a set of thematic challenges for science, policy and governance, based around cross-scale dynamics, complexity and uncertainty. A case study of the Saskatchewan River basin (SRB) in western Canada is presented, which encompasses many of the water-security challenges faced worldwide. A science agenda is defined based on the development of the SRB as a large-scale observatory to develop the underpinning science and social science needed to improve our understanding of water futures under societal and environmental change. We argue that non-stationarity poses profound challenges for existing science and that new integration of the natural sciences, engineering and social sciences is needed to address decision making under deep uncertainty. We suggest that vulnerability analysis can be combined with scenario-based modelling to address issues of water security and that knowledge translation should be coupled with place-based modelling, adaptive governance and social learning to address the complexity uncertainty and scale dynamics of contemporary water problems.
    Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences 01/2013; 371(2002):20120409. · 2.89 Impact Factor
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    ABSTRACT: Increasing evidence demonstrates that unsustainable land use practices result in human-induced drought conditions, and inadequate water supplies constrain land development in growing cities. Nonetheless, organizational barriers impair coordinated land and water management. Land planning is strongly influenced by political realities and interest groups, while water management is focused on the single-minded goal of providing reliable water for future development, often set apart from other priorities. Survey results from Portland, OR, and Phoenix, AZ, show that water managers and land planners are generally aware of the physical interconnections between land and water, but there is little cross-sector involvement in the two cities. Focusing on shared concerns about outdoor water use, climate variability, and water-sensitive urban design is a fruitful first step in integrating the practices of land planning and water management for climate adaptation and sustainable resource use.
    Society and Natural Resources 01/2013; 276(3):356-364. · 1.09 Impact Factor
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    ABSTRACT: This study assessed the spatial distribution of vulnerability to extreme heat in 1990 and 2000 within metropolitan Phoenix based on an index of seven equally weighted measures of physical exposure and adaptive capacity. These measures were derived from spatially interpolated climate, normalized differential vegetation index, and U.S. Census data. From resulting vulnerability maps, we also analyzed population groups living in areas of high heat vulnerability. Results revealed that landscapes of heat vulnerability changed substantially in response to variations in physical and socioeconomic factors, with significant alterations to spatial distribution of vulnerability especially between eastern and western sectors of Phoenix. These changes worked to the detriment of Phoenix's Hispanic population and the elderly concentrated in urban-fringe retirement communities. Este estudio evaluó la distribución espacial de la vulnerabilidad al calor extremo en 1990 y el 2000 dentro del área metropolitana de Phoenix, sobre la base de un índice de siete medidas igualmente ponderadas de exposición física y capacidad de adaptación. Estas medidas se derivan del clima interpolado espacialmente, del índice normalizado de vegetación diferencial, y datos censales de EE.UU. A partir de mapas de vulnerabilidad también se analizaron grupos de población que viven en zonas con vulnerabilidad a las altas temperaturas. Los resultados revelaron que los paisajes con vulnerabilidad al calor cambiaron sustancialmente en respuesta a variaciones en factores físicos y socioeconómicos, con modificaciones importantes en la distribución espacial de la vulnerabilidad, especialmente entre los sectores este y oeste de Phoenix. Estos cambios se dieron en detrimento de la población hispana de Phoenix y los ancianos concentrados en comunidades de jubilación urbano-marginales.
    The Professional Geographer 05/2012; 64(2):286-302. · 1.41 Impact Factor
  • Patricia Gober
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    ABSTRACT: Water security is concerned with the ability of water systems to deal effectively with environmental and social change. At the heart of this challenge is the capacity to make decisions about water in the face of uncertainties about climate, land use, population growth, global economic change, and lifestyle trends and in settings where people hold profoundly different attitudes about the value, meaning, and use of water. Traditional optimization models for water resource management are giving way to exploratory simulation tools that enable users to delve into a range of climate futures and policy options—to decide what kind of future they want and what they are willing to give up to get there. Ideally, these models are both products and processes—products in the sense that they integrate the best science about climate, hydrology, land use, demography, and economy and processes in that they are created in an iterative and collaborative process with stakeholders. This paper will highlight efforts of the Decision Center for a Desert City at Arizona State University to develop WaterSim 4.0 to simulate water shortage conditions in Phoenix under climate change, population growth, urban design, and water policy scenarios and to engage it for decision analysis, scenario planning, and climate adaptation. Interaction with stakeholders reflects inevitable trade-offs between future growth, preferred lifestyles, and the risk of future shortage.
    American Association for the Advancement of Science 2012 Annual Meeting; 02/2012
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    ABSTRACT: Changes in land use and land cover alter the local energy balance and contribute to distinct urban climates. This paper presents a local-scale above-canopy study of intra-urban land cover mixes in two cities to analyse the relative effects of surface morphology and local climate on the surface energy balance (SEB). The study is conducted for urban areas in Phoenix, Arizona, and Portland, Oregon, cities with distinct climates but similarly warm and dry summers. A Local-Scale Urban Meteorological Parameterization Scheme (LUMPS) is used to analyse the relative contributions of local weather extremes and land cover variations on the urban energy balance. The partitioning of net all-wave radiation into turbulent sensible and latent heat fluxes as well as heat storage is investigated for a typical dry summer month and two extreme weather scenarios in the two cities. Results of sensitivity analyses show that incoming solar radiation is an important driver of the SEB in LUMPS and should be considered in the generation of climate scenarios. The relationship between individual land cover fractions and SEB fluxes is not clear because of interrelated effects of surface characteristics in the land cover mix. Daytime Bowen ratios vary inversely with vegetation fraction between and within cities for all weather scenarios. Impervious surface cover is positively correlated to the available energy that is partitioned into sensible heat. Cumulative evapotranspiration (ET) is similar for average weather conditions across medium wet sites in Phoenix and Portland but varies more in Portland than in Phoenix under extreme weather conditions. Results suggest that land cover manipulation could offset influences of weather extremes on ET in Portland to a certain degree but not in Phoenix. These findings highlight the importance of spatial and climatic context in the urban design process to mitigate the effects of urbanization. Copyright © 2011 Royal Meteorological Society
    International Journal of Climatology 08/2011; · 3.40 Impact Factor
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    ABSTRACT: Uncertainty in future water supplies for the Phoenix Metropolitan Area (Phoenix) are exacerbated by the near certainty of increased, future water demands; water demand may increase eightfold or more by 2030 for some communities. We developed a provider-based water management and planning model for Phoenix termed WaterSim 4.0. The model combines a FORTRAN library with Microsoft C# to simulate the spatial and temporal dynamics of current and projected future water supply and demand as influenced by population demographics, climatic uncertainty, and groundwater availability. This paper describes model development and rationale. Water providers receive surface water, groundwater, or both depending on their portfolio. Runoff from two riverine systems supplies surface water to Phoenix while three alluvial layers that underlie the area provide groundwater. Water demand was estimated using two approaches. One approach used residential density, population projections, water duties, and acreage. A second approach used per capita water consumption and separate population growth estimates. Simulated estimates of initial groundwater for each provider were obtained as outputs from the Arizona Department of Water Resources (ADWR) Salt River Valley groundwater flow model (GFM). We compared simulated estimates of water storage with empirical estimates for modeled reservoirs as a test of model performance. In simulations we modified runoff by 80%-110% of the historical estimates, in 5% intervals, to examine provider-specific responses to altered surface water availability for 33 large water providers over a 25-year period (2010-2035). Two metrics were used to differentiate their response: (1) we examined groundwater reliance (GWR; that proportion of a providers' portfolio dependent upon groundwater) from the runoff sensitivity analysis, and (2) we used 100% of the historical runoff simulations to examine the cumulative groundwater withdrawals for each provider. Four groups of water providers were identified, and discussed. Water portfolios most reliant on Colorado River water may be most sensitive to potential reductions in surface water supplies. Groundwater depletions were greatest for communities who were either 100% dependent upon groundwater (urban periphery), or nearly so, coupled with high water demand projections. On-going model development includes linking WaterSim 4.0 to the GFM in order to more precisely model provider-specific estimates of groundwater, and provider-based policy options that will enable "what-if" scenarios to examine policy trade-offs and long-term sustainability of water portfolios.
    Journal of Environmental Management 06/2011; 92(10):2596-610. · 3.06 Impact Factor
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    ABSTRACT: In using traditional digital classification algorithms, a researcher typically encounters serious issues in identifying urban land cover classes employing high resolution data. A normal approach is to use spectral information alone and ignore spatial information and a group of pixels that need to be considered together as an object. We used QuickBird image data over a central region in the city of Phoenix, Arizona to examine if an object-based classifier can accurately identify urban classes. To demonstrate if spectral information alone is practical in urban classification, we used spectra of the selected classes from randomly selected points to examine if they can be effectively discriminated. The overall accuracy based on spectral information alone reached only about 63.33%. We employed five different classification procedures with the object-based paradigm that separates spatially and spectrally similar pixels at different scales. The classifiers to assign land covers to segmented objects used in the study include membership functions and the nearest neighbor classifier. The object-based classifier achieved a high overall accuracy (90.40%), whereas the most commonly used decision rule, namely maximum likelihood classifier, produced a lower overall accuracy (67.60%). This study demonstrates that the object-based classifier is a significantly better approach than the classical per-pixel classifiers. Further, this study reviews application of different parameters for segmentation and classification, combined use of composite and original bands, selection of different scale levels, and choice of classifiers. Strengths and weaknesses of the object-based prototype are presented and we provide suggestions to avoid or minimize uncertainties and limitations associated with the approach.
    Remote Sensing of Environment 05/2011; 115(5). · 5.10 Impact Factor
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    ABSTRACT: WaterSim, a simulation model, was built and implemented to investigate how alternative climate conditions, rates of population growth, and policy choices interact to affect future water supply and demand conditions in Phoenix, AZ. WaterSim is a hierarchical model that represents supply from surface and groundwater sources and demand from residential, commercial, and agricultural user sectors, incorporating the rules that govern reservoirs, aquifer use, and land-use change. In this paper we: (1) report on the imperative for exploratory modeling in water-resource management, given the deep uncertainties of climate change, (2) describe the geographic context for the Phoenix case study, (3) outline the objectives and structure of WaterSim, (4) report on testing the model with sensitivity analyses and history matching, (5) demonstrate the application of the model through a series of simulation experiments, and (6) discuss the model’s use for scenario planning and climate adaptation. Simulation results show there are significant challenges to Phoenix’s water sustainability from climate change and rapid growth. Policies to address these challenges require difficult tradeoffs among lifestyles, groundwater sustainability, the pace of growth, and what is considered to be an appropriate level of risk of climate-induced shortage.
    Environment and Planning B Planning and Design 01/2011; 38(2):197-215. · 0.83 Impact Factor
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    ABSTRACT: The Decision Center for a Desert City has a new provider-level water planning and management model termed WaterSim 4.0. This model simulates the spatial and temporal dynamics of current and projected future water supply and demand as influenced by population demographics, climatic uncertainty, and ground water availability for 33 water providers in the Phoenix Metropolitan Area (hereafter ``Phoenix''). WaterSim 4.0 uses a multi-language nested architecture that consists of a user interface, runtime libraries, and a DOS batch executable. The C# interface defines the inputs for, and manages the outputs from, the C# libraries that invoke a FORTRAN library and the batch program. The FORTRAN Dynamic Link Library (DLL) houses the water provider information, and it controls the watershed inputs and outputs and reservoir operations. The DOS executable is the Arizona Department of Water Resources (ADWR) Regional Groundwater Flow Model of the Salt River Valley (SRV) (hereafter SRVGFM). SRVGFM is based on MODFLOW and, as used here, runs on an annual time-step at a 1/4 mile by 1/4 mile spatial resolution (SRV grid). The SRV grid incorporates the three distinct alluvial layers of the aquifer present under Phoenix. A simulation cycle, then, proceeds thusly. First, the interface calls the C# libraries to execute the SRVGFM which runs for one year; annual outputs from the SRVGFM include, among other things, head levels for each alluvial layer. Post-processing of the SRVGFM outputs enables run-time verification of model convergence within a DOS box. Second, head levels from the SRVgfm are read by the C# libraries to update the spatial estimates of groundwater. Third, these groundwater estimates are made available to the FORTRAN DLL which then also runs for one year. Fourth, annual changes in the state and rate variables from the FORTRAN DLL (rivers, reservoirs, population demographics, etc.) are passed to the interface to provide tabular and graphical outputs from the simulation, and to update the input files for the next SRVGFM run (i.e., cell-specific estimates of groundwater pumping or recharge). Challenges to this architecture are many, but two are salient: (1) validating our water demand estimates, and (2) verifying and validating the cell-by-cell estimates of pumping or recharge for municipal and non-municipal entities. Opportunities for this architecture are also many, but a key use of this model may be the ability to examine potential vulnerability in surface and groundwater water resources for Valley water providers. We present the head levels for the middle alluvial layer for the SRV, as an example of model capabilities, for two time periods.
    AGU Fall Meeting Abstracts. 12/2010;
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    Patricia Gober, Craig W Kirkwood
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    ABSTRACT: Global warming has profound consequences for the climate of the American Southwest and its overallocated water supplies. This paper uses simulation modeling and the principles of decision making under uncertainty to translate climate information into tools for vulnerability assessment and urban climate adaptation. A dynamic simulation model, WaterSim, is used to explore future water-shortage conditions in Phoenix. Results indicate that policy action will be needed to attain water sustainability in 2030, even without reductions in river flows caused by climate change. Challenging but feasible changes in lifestyle and slower rates of population growth would allow the region to avoid shortage conditions and achieve groundwater sustainability under all but the most dire climate scenarios. Changes in lifestyle involve more native desert landscaping and fewer pools in addition to slower growth and higher urban densities. There is not a single most likely or optimal future for Phoenix. Urban climate adaptation involves using science-based models to anticipate water shortage and manage climate risk.
    Proceedings of the National Academy of Sciences 12/2010; 107(50):21295-9. · 9.81 Impact Factor
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    ABSTRACT: The uncertainties associated with global climate models pose substantial hurdles for urban water planning. Despite growing consensus among climatologists that the American Southwest is headed for a warmer and drier future, water planners in metropolitan Phoenix and elsewhere are reluctant to consider long-term climate change as a significant factor in increased risk of future water scarcity. A new paradigm for climate research and water planning is needed—one that is based on an assumption of uncertainty and a vision of multiple plausible futures, managing risk, and adaptive behaviors. To this end, we downscaled global climate models from the Intergovernmental Panel on Climate Change Third and Fourth Assessment Reports for the watersheds north of Phoenix and estimated changes in runoff using a hydrological model. Results then were used as inputs to WaterSim, an integrated simulation model of water supply and demand in Phoenix. The model simulated “what if” scenarios under varying policy decisions and future climates. Results of simulation experiments suggest that (1) current levels of per capita water consumption cannot be supported without unsustainable groundwater use under most climate model scenarios, (2) feasible reductions in residential water consumption allow the region to weather the most pessimistic of the climate projections, (3) delaying action reduces long-term sustainability of the groundwater resource under some climate scenarios, and (4) adaptive policy with appropriate monitoring to track groundwater provides warning that the need for use restrictions is approaching and avoids the need for drastic, ad hoc actions. Las incertidumbres asociadas con los modelos climáticos globales ponen serios obstáculos a la planificación del agua en áreas urbanas. Pese al creciente consenso de los climatólogos sobre un sudoeste norteamericano cada vez más cálido y seco, los planificadores del agua en el espacio metropolitano de Phoenix y otras áreas se muestran renuentes a tomar en cuenta el cambio climático a largo plazo como factor significativo de mayor riesgo de escasez de agua en el futuro. Se necesita, pues, un nuevo paradigma de investigación climática y planificación hídrica—uno que se base en el supuesto de la incertidumbre y que tome en cuenta una visión de múltiples futuros plausibles, manejo de riesgos y conductas adaptativas. Con esta necesidad en mente, bajamos la escala de los modelos globales del clima utilizados en los Informes Tercero y Cuarto de Evaluación del Panel Intergubernamental sobre Cambio Climático, para aplicarlos a la cuenca situada al norte de Phoenix, y calculamos los cambios en escorrentía mediante el uso de un modelo hidrológico. Los resultados se utilizaron como input del WaterSim, un modelo de simulación integrado sobre suministro y demandas de agua en Phoenix. El modelo simuló escenarios probables condicionados por variadas decisiones políticas y alternativas climáticas futuras. Los resultados de las simulaciones experimentales sugieren que (1) los actuales niveles de consumo de agua per cápita no pueden mantenerse sin el apoyo insostenible de agua subterránea dentro de la mayoría de los escenarios contemplados en el modelo climático; (2) las reducciones viables en el consumo residencial de agua permiten a la región sobrellevar las condiciones más pesimistas de las proyecciones climáticas; (3) aplazar la acción reduce la sustentabilidad a largo plazo del recurso subterráneo de agua dentro de algunos escenarios climáticos, y (4) las políticas de adaptación con monitoreo apropiado del agua subterránea generan indicios de que nos aproximamos a la necesidad de utilizar restricciones que puedan evitar la necesidad de aplicar acciones intempestivas drásticas.
    Annals of the Association of American Geographers 04/2010; 100(2):356-372. · 2.17 Impact Factor
  • S. Guhathakurta, P. Gober
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    ABSTRACT: While previous studies have shown that urban heat islands (UHI) tend to increase residential water use, they have not yet analyzed the feedbacks among vegetation intensity, diurnal temperature variation, water use, and characteristics of the built environment. This study examines these feedback relationships with the help of a path model applied to spatially disaggregated data from Phoenix, Arizona. The empirical evidence from the observations in Phoenix suggests the following: (1) impervious surfaces contribute to increased residential water use by exacerbating UHI; (2) larger lots containing pools and mesic vegetation increase water demand by reducing diurnal temperature difference; and (3) smart design of urban environments needs to go beyond simplistic water body- and vegetation-based solutions for mitigating uncomfortably high temperatures and consider interactions between surface materials, land use, UHI, and water use.
    Journal of Planning Education and Research 01/2010; 29(3). · 1.46 Impact Factor
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    ABSTRACT: Problem -- The prospect that urban heat island (UHI) effects and climate change may increase urban temperatures is a problem for cities that actively promote urban redevelopment and higher densities. One possible UHI mitigation strategy is to plant more trees and other irrigated vege- tation to prevent daytime heat storage and facilitate nighttime cooling, but this requires water resources that are limited in a desert city like Phoenix. Purpose -- We investigated the tradeoffs between water use and nighttime cooling inherent in urban form and land use choices. Methods: We used a Local-Scale Urban Meteorological Parameterization Scheme (LUMPS) model to examine the variation in temperature and evaporation in 10 census tracts in Phoenix’s urban core. After vali- dating results with estimates of outdoor water use based on tract-level city water records and satellite imagery, we used the model to simulate the temperature and water use consequences of implementing three different scenarios. Results and conclusions -- We found that increasing irrigated landscaping lowers nighttime temperatures, but this relationship is not linear; the greatest reductions occur in the least vegetated neighborhoods. A ratio of the change in water use to temperature impact reached a threshold beyond which increased outdoor water use did little to ameliorate UHI effects. Takeaway for practice -- There is no one design and landscape plan capable of addressing increasing UHI and climate effects everywhere. Any one strategy will have inconsistent results if applied across all urban landscape features and may lead to an inefficient allocation of scarce water resources. Keywords -- urban heat island (UHI), LUMPS model, scenarios, urban heat island mitigation, water resource planning Research Support: This work was supported by the National Science Foun- dation (NSF) under Grant SES-0345945 (Decision Center for a Desert City) and by the City of Phoenix Water Services Depart- ment. Any opinions, findings, and conclu- sions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of NSF.
    Journal of the American Planning Association 01/2010; 76(1):109-121. · 2.04 Impact Factor
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    Patricia Gober
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    ABSTRACT: Arid regions and their cities are vulnerable to future water scarcity because climate change threatens to reduce supply and rapid growth increases demand. The study of water sustainability in these regions and cities transcends concern about climate change and growth, however, and includes the dynamics of water–energy relationships, tradeoffs involved in the use of irrigated landscaping for temperature amelioration, and feedbacks between urban growth, the economy, and the environment. It requires analysis of how complex human and biophysical systems function at a range of scales and calls for new tools for risk assessment and decision support incorporating decision making under uncertainty.
    Current Opinion in Environmental Sustainability 01/2010; 2:144-150. · 3.17 Impact Factor

Publication Stats

525 Citations
97.12 Total Impact Points

Institutions

  • 2013–2014
    • University of Saskatchewan
      • • Department of Civil and Geological Engineering
      • • Global Institute for Water Security
      Saskatoon, Saskatchewan, Canada
  • 1981–2012
    • Arizona State University
      • • Decision Theater
      • • School of Geographical Sciences and Urban Planning
      Phoenix, Arizona, United States