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Geology topics

Annika Quick

Publications and source records attributed to Annika Quick.

3 recordsLinked to original sources

Urban heterogeneity drives dissolved organic matter sources, transport, and transformation from local to macro scales

Urbanization reshapes dissolved organic matter (DOM) sources, transport, and transformations through changes in vegetation, hydrology, and management of waste and water. Yet the impacts of urbanization on DOM are variable within and among cities. Predicting heterogeneous responses to urbanization is challenged by diverse human activities and underlying biophysical variation along stream networks. Using data from the 486 largest urban areas in the continental United States and seven focal cities, we identified macro and local scale urban gradients in social, built, and biophysical factors that are expected to shape DOM. We used these gradients and the literature to develop hypotheses about heterogeneity in DOM quantity and quality within and among cities. Interactions among landscape and infrastructure attributes across spatial and temporal scales result in heterogeneous responses in DOM. Characterizing and quantifying these inconsistent responses to urbanization in contrasting settings may help to better understand heterogeneity and identify generalities among urban watersheds.

continental United States

Salting behaviors influence urban stream conductivity in Boston, Massachusetts (USA)

Freshwater salinization is a major concern in temperate climates where road salt is used as a deicer to manage snow and ice on roadways. In urban and suburban areas, wastewater, weathering of infrastructure, and salting on parking lots and sidewalks can also contribute to salt contamination, but little is known about how well these sources explain variation in stream conductivity and what factors may mitigate high conductivity in streams. We collected specific conductance samples seasonally over 1 y at 100 stream sites in the greater Boston (Massachusetts, USA) metropolitan area, which reflected a gradient of land use/cover and sociodemographic variables. We also continuously monitored specific conductance over 1 y (November 2021–December 2022) at 3 streams with different levels of impervious cover. Baseflow conductivity from grab samples was best explained by % impervious cover (positive relationship) and season (highest median conductivity in summer and early autumn) ( r 2 = 0.47, p < 0.001). At high impervious cover, watersheds with higher housing vacancy had lower conductivity, suggesting that resident salting behavior may affect conductivity. Continuous conductivity varied with discharge, with spikes in conductivity coincident with increases in discharge in the winter, likely due to the influx of road salt into waterways. In the summer, higher discharge was linked with sharp decreases in conductivity, suggesting that storm flows dilute high baseflow conductivity, although combined sewer overflows caused secondary conductivity pulses. Overall, conductivity was highest during winter storm pulses, but elevated conductivity levels persisted throughout the year, especially in more impervious watersheds. Our research suggests that reduced salt application and street sweeping may reduce conductivity but will not prevent continued salinization. Temporal patterns of conductivity highlight the importance of seasonal road-salt application (winter), seasonal climate (low-flow summers), and precipitation (storm events, droughts) in influencing stream conductivity and can guide monitoring design, policymaking, and management decisions under climate uncertainty.

Massachusetts

Overcoming challenges in mapping hydrography and heterogeneity in urban landscapes

Understanding how water moves through a watershed is one of the most fundamental yet often complicated aspects of hydrology, especially in urban areas. Urban infrastructure and water management alter natural hydrological pathways in developed watersheds, which can violate assumptions of a watershed approach to ecosystem science. We focus on two aspects of urban landscapes that often create challenges to model watershed processes within and among urban areas: (1) accurate delineation of urban flow paths and (2) consistent characterisation of the urban landscape within and among cities. Here, we describe these challenges and identify how certain components of these challenges can be addressed, highlighting examples and lessons learned in a project that is assessing scales and drivers of variability in dissolved organic carbon across five urban centres in the United States. Our goal is to facilitate a dialogue that will advance the applications of watershed approaches in urban ecosystem science by recognising and addressing these challenges. Our examples focus on the United States but could be applicable to similar urban challenges in other locations globally.

Florida, Massachusetts, Utah