Browsing by Author "Botter, Gianluca"

Now showing 1 - 7 of 7
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    Hierarchical climate-driven dynamics of the active channel length in temporary streams
    Botter, Gianluca; Vingiani, Filippo; Senatore, Alfonso; Jensen, Carrie K.; Weiler, Markus; McGuire, Kevin J.; Mendicino, Giuseppe; Durighetto, Nicola (Springer, 2021-12)
    Looking across a landscape, river networks appear deceptively static. However, flowing streams expand and contract following ever-changing hydrological conditions of the surrounding environment. Despite the ecological and biogeochemical value of rivers with discontinuous flow, deciphering the temporary nature of streams and quantifying their extent remains challenging. Using a unique observational dataset spanning diverse geomorphoclimatic settings, we demonstrate the existence of a general hierarchical structuring of river network dynamics. Specifically, temporary stream activation follows a fixed and repeatable sequence, in which the least persistent sections activate only when the most persistent ones are already flowing. This hierarchical phenomenon not only facilitates monitoring activities, but enables the development of a general mathematical framework that elucidates how climate drives temporal variations in the active stream length. As the climate gets drier, the average fraction of the flowing network decreases while its relative variability increases. Our study provides a novel conceptual basis for characterizing temporary streams and quantifying their ecological and biogeochemical impacts.
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    Linking water age and solute dynamics in streamflow at the Hubbard Brook Experimental Forest, NH, USA
    Benettin, Paolo; Bailey, Scott W.; Campbell, John L.; Green, M. B.; Rinaldo, Andrea; Likens, Gene E.; McGuire, Kevin J.; Botter, Gianluca (American Geophysical Union, 2015-11-01)
    We combine experimental and modeling results from a headwater catchment at the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA, to explore the link between stream solute dynamics and water age. A theoretical framework based on water age dynamics, which represents a general basis for characterizing solute transport at the catchment scale, is here applied to conservative and weatheringderived solutes. Based on the available information about the hydrology of the site, an integrated transport model was developed and used to compute hydrochemical fluxes. The model was designed to reproduce the deuterium content of streamflow and allowed for the estimate of catchment water storage and dynamic travel time distributions (TTDs). The innovative contribution of this paper is the simulation of dissolved silicon and sodium concentration in streamflow, achieved by implementing first-order chemical kinetics based explicitly on dynamic TTD, thus upscaling local geochemical processes to catchment scale. Our results highlight the key role of water stored within the subsoil glacial material in both the short-term and long-term solute circulation. The travel time analysis provided an estimate of streamflow age distributions and their evolution in time related to catchment wetness conditions. The use of age information to reproduce a 14 year data set of silicon and sodium stream concentration shows that, at catchment scales, the dynamics of such geogenic solutes are mostly controlled by hydrologic drivers, which determine the contact times between the water and mineral interfaces. Justifications and limitations toward a general theory of reactive solute circulation at catchment scales are discussed.
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    Probabilistic Description of Streamflow and Active Length Regimes in Rivers
    Durighetto, Nicola; Mariotto, Veronica; Zanetti, Francesca; McGuire, Kevin J.; Mendicino, Giuseppe; Senatore, Alfonso; Botter, Gianluca (American Geophysical Union, 2022-04-01)
    In spite of the prevalence of temporary rivers over a wide range of climatic conditions, they represent a relatively understudied fraction of the global river network. Here, we exploit a well-established hydrological model and a derived distribution approach to develop a coupled probabilistic description for the dynamics of the catchment discharge and the corresponding active network length. Analytical expressions for the flow duration curve (FDC) and the stream length duration curve (SLDC) were derived and used to provide a consistent classification of streamflow and active length regimes in temporary rivers. Two distinct streamflow regimes (persistent and erratic) and three different types of active length regimes (ephemeral, perennial, and ephemeral de facto) were identified depending on the value of two dimensionless parameters. These key parameters, which are related to the underlying streamflow fluctuations and the sensitivity of active length to changes in the catchment discharge (here quantified by the scaling exponent b), originate seven different behavioral classes characterized by contrasting shapes of the underlying SLDCs and FDCs. The analytical model was tested using data gathered in three study catchments located in Italy and USA, with satisfactory model performances in most cases. Our analytical and empirical results show the existence of a structural relationship between streamflow and active length regimes, which is chiefly modulated by the scaling exponent b. The proposed framework represents a promising tool for the coupled analysis of discharge and river network length dynamics in temporary streams.
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    Reply to comment by Porporato and Calabrese on "Storage selection functions: A coherent framework for quantifying how catchments store and release water and solutes''
    Rinaldo, Andrea; Benettin, Paolo; Harman, C. J.; Hrachowitz, M.; McGuire, Kevin J.; van der Velde, Y.; Bertuzzo, E.; Botter, Gianluca (American Geophysical Union, 2016-01-01)
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    Storage selection functions: A coherent framework for quantifying how catchments store and release water and solutes
    Rinaldo, Andrea; Benettin, Paolo; Harman, C. J.; Hrachowitz, M.; McGuire, Kevin J.; van der Velde, Y.; Bertuzzo, E.; Botter, Gianluca (American Geophysical Union, 2015-06-01)
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    Transit Time Estimation in Catchments: Recent Developments and Future Directions
    Benettin, Paolo; Rodriguez, Nicolas B.; Sprenger, Matthias; Kim, Minseok; Klaus, Julian; Harman, Ciaran J.; Velde, Ype; Hrachowitz, Markus; Botter, Gianluca; McGuire, Kevin J.; Kirchner, James W.; Rinaldo, Andrea; McDonnell, Jeffrey J. (American Geophysical Union, 2022-11-14)
    Water transit time is now a standard measure in catchment hydrological and ecohydrological research. The last comprehensive review of transit time modeling approaches was published 15+ years ago. But since then the field has largely expanded with new data, theory and applications. Here, we review these new developments with focus on water-age-balance approaches and data-based approaches. We discuss and compare methods including StorAge-Selection functions, well/partially mixed compartments, water age tracking through spatially distributed models, direct transit time estimates from controlled experiments, young water fractions, and ensemble hydrograph separation. We unify some of the heterogeneity in the literature that has crept in with these many new approaches, in an attempt to clarify the key differences and similarities among them. Finally, we point to open questions in transit time research, including what we still need from theory, models, field work, and community practice.
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    Young runoff fractions control streamwater age and solute concentration dynamics
    Benettin, Paolo; Bailey, Scott W.; Rinaldo, Andrea; Likens, Gene E.; McGuire, Kevin J.; Botter, Gianluca (2017-07-31)
    We introduce a new representation of coupled solute and water age dynamics at the catchment scale, which shows how the contributions of young runoff waters can be directly referenced to observed water quality patterns. The methodology stems from recent trends in hydrologic transport that acknowledge the dynamic nature of streamflow age and explores the use of water age fractions as an alternative to the mean age. The approach uses a travel time-based transport model to compute the fractions of streamflow that are younger than some thresholds (e.g., younger than a few weeks) and compares them to observed solute concentration patterns. The method is here validated with data from the Hubbard Brook Experimental Forest during spring 2008, where we show that the presence of water younger than roughly 2 weeks, tracked using a hydrologic transport model and deuterium measurements, mimics the variation in dissolved silicon concentrations. Our approach suggests that an age-discharge relationship can be coupled to classic concentration-discharge relationship, to identify the links between transport timescales and solute concentration. Our results highlight that the younger streamflow components can be crucial for determining water quality variations and for characterizing the dominant hydrologic transport dynamics.