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Nancy Grimm

    Nancy Grimm

    The impacts of climate change on water and nitrogen cycles in arid central Arizona (USA) were investigated by integrating the Second Generation Coupled Global Climate Model (CGCM2) and a widely used, physical process-based model, Soil and... more
    The impacts of climate change on water and nitrogen cycles in arid central Arizona (USA) were investigated by integrating the Second Generation Coupled Global Climate Model (CGCM2) and a widely used, physical process-based model, Soil and Water Assessment Tool (SWAT). With statistically downscaled daily climate data from the CGCM2 as model input, SWAT predicted increased potential evapotranspiration and decreased surface runoff, lateral flow, soil water, and groundwater recharge, which suggests serious consequences for the water cycle in this desert catchment in the future. Specifically, stream discharge is projected to decrease by 31 % in the 2020s, 47 % in the 2050s, and 56 % in the 2080s compared to the mean discharge for the base period (0.73 m3/s). A flow-duration analysis reveals that the projected reduction of stream discharge in the future is attributable to significant decreases in mid-range and low-flow conditions; however, flood peaks would show a slight increase in the future. The drier and hotter future also will decrease the rate of nitrogen mineralization in the catchment and ultimately, nitrate export from the stream. Since mean mineralization rate would decrease by 15 % in the 2020s, 28 % in the 2050s, and 35 % in the 2080s compared to the based period (9.3 g N ha−1 d−1), the combined impact of reduced catchment mineralization and reduced streamflow would predict declining nitrate export: from today’s mean value of 30 kg N/d, to 20, 15 and 12 kg N/d by the 2020s, 2050s, and 2080s, respectively.
    ABSTRACT Atmospheric nitrogen (N) input to soils and surfaces in arid environments is of growing concern due to increased N emissions and N use associated with urbanization. Atmospheric N that falls as wet (rain or snow) or dry (dust or... more
    ABSTRACT Atmospheric nitrogen (N) input to soils and surfaces in arid environments is of growing concern due to increased N emissions and N use associated with urbanization. Atmospheric N that falls as wet (rain or snow) or dry (dust or aerosols) deposition can lead to eutrophication, soil acidification, and groundwater contamination through leaching of excess nitrate. Other nitrate sources include anthropogenic fertilizer from agriculture practices or lawn application, septic systems, and animal waste. Urbanization increases imperviousness and alters natural flowpaths through construction of stormwater infrastructure, which alters hydrological connectivity. Following a rain pulse, nitrate deposited on impervious surfaces during dry periods may be mobilized and, depending on the type of stormwater infrastructure, has the potential to reach aquifers. In this study, we investigate the sources of nitrate found in urban stormwater by undertaking multiple-isotope analysis (δ15N, δ18O and Δ17O) on water samples collected from several sub-catchments within the Indian Bend Wash catchment in Scottsdale, Arizona, that represent different types of stormwater infrastructure, including pipes, engineered washes, retention basins and mixed infrastructure at larger spatial scales. We use δ15N of nitrate to distinguish among nitrate sources; pairing δ15N and δ18O provides more precise separation due to distinct signatures (e.g., fertilizer is unique from septic sources). Because atmospheric nitrate is anomalously enriched in 17O (denoted Δ17O) and nitrate produced from nitrification, denitrification and assimilation have a Δ17O = 0, we are able to use the Δ17O measurement to determine the proportion of nitrate in runoff that is derived from atmospheric sources. Multiple isotopic analyses were performed using the denitrifier method on runoff samples collected during summer (monsoonal) and winter storms that occurred between 2010 and 2011. Typical ranges of atmospheric nitrate inputs are 20-70% (maximum 95% and minimum 0%). The proportion of atmospheric nitrate in runoff samples changes over the course of the storms, suggesting different pools of nitrate are being mobilized by changing hydrologic conditions. Results indicate that in hydrologically responsive and frequently flushed catchments (in which runoff typically has lower nitrate concentrations), most of the nitrate is derived from atmospheric sources (up to 95%), while in catchments with wash and retention basin infrastructure, between 20 and 70% of nitrate is derived from atmospheric sources. Thus, these results indicate that the type of stormwater infrastructure and drainage substrate, such as concrete or vegetated washes have a great influence on N cycling in urban systems.
    Ecosystem services derive from underlying ecosystem processes but are distinguished by their benefits to society. Among ecosystem services, those associated with biogeochemical cycling and regulation of water, air, and soil quality are... more
    Ecosystem services derive from underlying ecosystem processes but are distinguished by their benefits to society. Among ecosystem services, those associated with biogeochemical cycling and regulation of water, air, and soil quality are relatively unrecognized by the public, although concentrations of some materials are regulated by local, state and national laws. The disconnection between their importance and the degree to which
    AGU's open‐access transdisciplinary science journal Earth's Future continued to grow in size and stature in 2019, with ~40% acceptance rate for ~280 new submissions that were evaluated by a similar number of external reviewers;... more
    AGU's open‐access transdisciplinary science journal Earth's Future continued to grow in size and stature in 2019, with ~40% acceptance rate for ~280 new submissions that were evaluated by a similar number of external reviewers; their names are listed here.
    In many disciplines, the resilience concept has applied to managing perturbations, challenges, or shocks in the system and designing an adaptive system. In particular, resilient infrastructure systems have been recognized as an... more
    In many disciplines, the resilience concept has applied to managing perturbations, challenges, or shocks in the system and designing an adaptive system. In particular, resilient infrastructure systems have been recognized as an alternative to traditional infrastructure, in which the systems are managed to be more reliable against unforeseen and unknown threats in urban areas. Perhaps owing to the malleable and multidisciplinary nature in the concept of resilience, there is no clear-cut standard that measures and characterizes infrastructure resilience nor how to implement the concept in practice for developing urban infrastructure systems. As a result, unavoidable subjective interpretation of the concept by practitioners and decision-makers occurs in the real world. We demonstrate the subjective perspectives on infrastructure resilience by asking practitioners working in governmental institutions within the metropolitan Phoenix area based on their interpretations of resilience, usin...
    Urban infrastructure will require transformative changes to adapt to changing disturbance patterns. We ask what new opportunities hybrid infrastructure-built environments coupled with landscape-scale biophysical structures and... more
    Urban infrastructure will require transformative changes to adapt to changing disturbance patterns. We ask what new opportunities hybrid infrastructure-built environments coupled with landscape-scale biophysical structures and processes-offer for building different layers of resilience critical for dealing with increased variation in the frequency, magnitude and different phases of climate-related disturbances. With its more diverse components and different internal logics, hybrid infrastructure opens up alternative and additive ways of building resilience for and through critical infrastructure, by providing a wider range of functions and responses. Second, hybrid infrastructure points toward greater opportunities for ongoing (re)design at the landscape level, where structure and function can be constantly renegotiated and recombined.
    Research Interests:
    Resilient cities are able to persist, grow, and even transform while keeping their essential identities in the face of external forces like climatechange, which threatens lives, livelihoods, and the structures and processes of the urban... more
    Resilient cities are able to persist, grow, and even transform while keeping their essential identities in the face of external forces like climatechange, which threatens lives, livelihoods, and the structures and processes of the urban environment (United Nations Office for Disaster Risk Reduction, How to make cities more resilient: a handbook for local government leaders. Switzerland, Geneva, 2017). Scenario development is a novel approach to visioning resilient futures for cities. As an instrument for synthesizing data and envisioning urban futures, scenarios combine diverse datasets such as biophysical models, stakeholder perspectives, and demographic information (Carpenter et al. Ecol Soc 20:10, 2015). As a tool to envision alternative futures, participatoryscenario development explores, identifies, and evaluates potential outcomes and tradeoffs associated with the management of social–ecological change, incorporating multiple stakeholder’s collaborative subjectivity (Galafassi...
    This data package is formatted according to the "ecocomDP", a data package design pattern for ecological community surveys, and data from studies of composition and biodiversity. For more information on the ecocomDP project see... more
    This data package is formatted according to the "ecocomDP", a data package design pattern for ecological community surveys, and data from studies of composition and biodiversity. For more information on the ecocomDP project see https://github.com/EDIorg/ecocomDP/tree/master, or contact EDI https://environmentaldatainitiative.org. This Level 1 data package was derived from the Level 0 data package found here: https://portal.edirepository.org/nis/mapbrowse?scope=knb-lter-cap&identifier=652&revision=2 The abstract below was extracted from the Level 0 data package and is included for context: The Ecological Survey of Central Arizona (ESCA) is an extensive field survey and integrated inventory designed to capture key ecological indicators of the CAP LTER study area consisting of the urbanized, suburbanized, and agricultural areas of metropolitan Phoenix, and the surrounding Sonoran desert. The survey, formerly known as the survey 200 and renamed to ESCA in 2015, is conducted every five years at approximately 200 sample plots (30m x 30m) that were located randomly using a tessellation-stratified dual-density sampling design. Study plots cover habitats throughout the CAP LTER study area ranging from native Sonoran desert sites to residential yards to an airport tarmac. Measurements include an inventory of all plants (identified to the lowest possible taxonomic unit, typically species), plant biovolume, soil coring for physicochemical properties, arthropod sweep-net sampling, photo documentation, and a visual survey of site and area characteristics. The objectives of the survey are to (1) characterize patches in terms of key biotic, physical, and chemical variables, and (2) examine relationships among land use, general plant diversity, native plant diversity, plant biovolume, soil nutrient status, and social-economic indices along an indirect urban gradient. A pilot survey was conducted in 1999, [...]
    Merging aquatic and terrestrial perspectives of nutrient biogeochemistry
    ABSTRACT Background/Question/Methods Over recent years urbanization has occurred rapidly, in particular in arid regions of the USA. Major changes in ecosystem structure occur during urbanization, including changes in land cover,... more
    ABSTRACT Background/Question/Methods Over recent years urbanization has occurred rapidly, in particular in arid regions of the USA. Major changes in ecosystem structure occur during urbanization, including changes in land cover, especially impervious surfaces, and hydrological flow paths due to the construction of stormwater infrastructure. These changes may have considerable implications for nutrient transport and redistribution within the urban ecosystem. In this study we investigate the effects of urban stormwater infrastructure on storm hydrographs and the hydrologically mediated transfer of dissolved and particulate nitrogen (N), phosphorus (P), and carbon (C) at multiple spatial scales. Storms were sampled in 11 hierarchically nested catchments, ranging in size from 5 ha to 17000 ha, in the Indian Bend Wash catchment in Scottsdale, Arizona, from summer 2010 to winter 2011. We contrast intense, spatially discrete summer monsoonal storms with less intense winter rainfall events that have broader spatial coverage. Results/Conclusions For N, P, and C, particle-bound nutrient transport accounts for a significant proportion of total nutrient flux. The transport of dissolved and particulate N, P, and C is governed primarily by flow characteristics, which vary depending on the extent and type of stormwater infrastructure. Across all sites, at high discharges the proportion of nutrients in particulate forms increases because of the increased capacity of flow to entrain and transport particulate organic material and sediment. The total export of dissolved and particle-bound materials from catchments increases with spatial scale, but export of materials per unit area actually decreases with an increase in spatial scale. There is discernible variation in mid-scale export of particulate material due to differences in stormwater infrastructure, with lowest exports from catchments with retention basins. Thus, changes in ecosystem structure resulting from designed ecosystems with different types of stormwater infrastructure exert a major control over the dynamics of particulate and dissolved nutrient redistribution within these catchments.
    ABSTRACT Background/Question/Methods The effects of urbanization on downstream ecosystems, particularly due to changes in nutrient inputs and altered hydrology are well studied. Less is known, however, about nutrient transport and... more
    ABSTRACT Background/Question/Methods The effects of urbanization on downstream ecosystems, particularly due to changes in nutrient inputs and altered hydrology are well studied. Less is known, however, about nutrient transport and processing within urban watersheds. Previous research has focused on the roles of land cover and land use but drainage system design and configuration also are apt to play a significant role in controlling the transport of water and nutrients downstream. Furthermore, variability in drainage systems within and between cities may lead to differences in the effects of urbanization on downstream ecosystems over time and space. We established a nested stormwater sampling network with 12 watersheds ranging in size from 5 to 17,000 ha in the Indian Bend Wash watershed in Scottsdale, AZ. Small (< 200ha) watersheds had uniform land cover (medium-density residential) but were drained by a variety of stormwater infrastructure including surface runoff, pipes, natural or engineered washes, and retention basins. We quantified discharge and precipitation at the outflow of each subwatershed and collected stormwater and rainfall samples for analyses of dissolved nitrogen (TDN) and phosphorus (PO4), and organic carbon (oC) over two years. Results/Conclusions On seasonal time scales, wash drained watersheds exported 80% less and retention basin drained watersheds exported 90% less TDN and PO4 per area than piped watersheds. Total seasonal nutrient loads were correlated with total discharge across sites. Within sites, runoff and nutrient loads were predicted by storm size. Runoff coefficients from piped watersheds did not change with storm size, whereas runoff coefficients for wash and retention basin sites increased linearly with storm size. Event-based nutrient loads from the wash and retention basin sites were nonlinearly related to storm size, and for exceptionally large events, nutrient loads from the wash drained sites were as high as event loads from the piped watersheds. Due to less frequent flushing, nutrient concentrations were higher from retention basin and wash than piped sites. We compared the cumulative nutrient load with cumulative discharge to evaluate nutrient flushing. Flushing was evident for some storms at all sites, although it was more common in piped and smaller watersheds. Within the large, wash-drained watershed, flushing was predicted strongly by rainfall intensity. Overall, we find that urban drainage infrastructure is characterized by a range of hydrologic connectivity. Infrastructure significantly alters hydrologic fluxes which are the main driver of nutrient fluxes.
    <p>The world is urbanizing while it undergoes dramatic environmental change, especially climate change. These two drivers are on a collision course that will exaccerbate challenges for cities. At the global and local scales, new... more
    <p>The world is urbanizing while it undergoes dramatic environmental change, especially climate change. These two drivers are on a collision course that will exaccerbate challenges for cities. At the global and local scales, new solutions will have to be found to build resilience in the cities of tomorrow. This assertion is explored through the lens of urban water systems: supply and delivery at the global scale, and stormwater management at the local scale. </p
    *Project overview* Protected lands, such as the McDowell Sonoran Preserve (hereafter referred to as the Preserve) in Scottsdale, Arizona, provide critical refuge for native biota and natural, ecological processes within and near urban... more
    *Project overview* Protected lands, such as the McDowell Sonoran Preserve (hereafter referred to as the Preserve) in Scottsdale, Arizona, provide critical refuge for native biota and natural, ecological processes within and near urban environments. At the same time, a key feature that makes urban, open-space preserves so valuable − their proximity to urban areas − places strain on the ecological integrity of these systems through visitation, habitat fragmentation, and the introduction of exotic species among others. Effective management of these systems requires detailed knowledge of the biota within the protected area, and monitoring of ecological indicators through time. Arthropods are well suited to monitoring ecological health. This diverse group of organisms typically reflects overall biological diversity of a system, and includes several trophic levels; their short generation times mean they will likely respond quickly to change; and they are relatively easy to sample. As part of a broad effort by the McDowell Sonoran Conservance Field Institute, an organization that oversees science and research in Preserve, to establish a baseline inventory of biota in the Preserve, investigators with the Central Arizona−Phoenix Long-Term Ecological Research (CAP LTER) program at Arizona State University (ASU) in collaboration with Field Institute Citizen Scientists are monitoring ground-dwelling arthropods at select locations that reflect a diversity of habitat within the Preserve. Investigators employ a sampling design that is intended to provide insight regarding influence of the urban-wildland interface on the arthropod community within the protected area. The simple but effective technique of pitfall trapping is used to sample ground-dwelling arthropods at select locations spanning a wide range of habitat with the Preserve. Additional collections of vegetation-dwelling arthropods have been conducted at the sampling locations at periodic intervals. *Project design and sampling* Pitfall trap transect locations include [...]
    We describe the rationale and framework for developing scenarios of positive urban futures. The scenario framework is conducted in participatory workshop settings and composed of three distinct scenario approaches that are used to (1)... more
    We describe the rationale and framework for developing scenarios of positive urban futures. The scenario framework is conducted in participatory workshop settings and composed of three distinct scenario approaches that are used to (1) explore potential outcomes of existing planning goals (strategic scenarios), (2) articulate visions that address pressing resilience challenges (adaptive scenarios), and (3) envision radical departures from the status quo in the pursuit of sustainability and equity (transformative scenarios). A series of creative and analytical processes are used to engage the community in imagining, articulating, and scrutinizing visions and pathways of positive futures. The approach offers an alternative and complement to traditional forecasting techniques by applying inspirational stories to resilience research and practice.
    Resilient urban futures provides a social–ecological–technological systems (SETS) perspective on promoting and understanding resilience. This chapter introduces the concepts, research, and practice of urban resilience from the Urban... more
    Resilient urban futures provides a social–ecological–technological systems (SETS) perspective on promoting and understanding resilience. This chapter introduces the concepts, research, and practice of urban resilience from the Urban Resilience to Extremes Sustainability Research Network (UREx SRN). It describes conceptual and methodological approaches to address how cities experience extreme weather events, adapt to climate resilience challenges, and can transform toward sustainable and equitable futures.
    Participatory scenario visioning aims to expose, integrate, and reconcile perspectives and expectations about a sustainable, resilient future from a variety of actors and stakeholders. This chapter considers the settings in which... more
    Participatory scenario visioning aims to expose, integrate, and reconcile perspectives and expectations about a sustainable, resilient future from a variety of actors and stakeholders. This chapter considers the settings in which transdisciplinary participatory visioning takes place, highlighting lessons learned from the Urban Resilience to Extremes Sustainability Research Network (UREx SRN). It reflects on the benefits of engaging in the co-production process and the challenges that must be considered amid this process.

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