Eco-hydrological modelling of channel network dynamics—part 1: stochastic simulation of active stream expansion and retraction

Royal Society Open Science, Journal Year: 2022, Volume and Issue: 9(11)

Published: Nov. 1, 2022

Dynamic changes in the active portion of stream networks represent a phenomenon common to diverse climates and geologic settings. However, mechanistically describing these processes at relevant spatiotemporal scales without huge computational burdens remains challenging. Here, we present novel stochastic framework for effective simulation channel network dynamics capitalizing on concept 'hierarchical structuring temporary streams'-a general principle identify activation/deactivation order nodes. The allows long-term description event-based river configuration starting from widely available climatic data (mainly rainfall evapotranspiration). Our results indicate that climate strongly controls temporal variations length, influencing not only preferential channels but also speed retraction during drying. Moreover, observed that-while statistics wet length are mainly dictated by underlying conditions-the spatial patterns reaches size largest connected patch controlled correlation local persistency. proposed provides robust mathematical set-up analysing multi-faceted ecological legacies dynamics, as discussed companion paper.

Language: Английский

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Ecological consequences of shifting habitat mosaics within and across years in an intermittent stream

Freshwater Biology, Journal Year: 2023, Volume and Issue: 68(7), P. 1161 - 1175

Published: April 26, 2023

Abstract Intermittent streams that cease to flow during dry periods represent more than half of the global river network, and are particularly common in arid semi‐arid regions. They characterised by high spatial temporal variability aquatic habitat, forming a shifting habitat mosaic supports diverse assemblages native endemic species. Climate projections for much world predict greater variation precipitation increasing drought severity, suggesting need better understand species' responses within intermittent stream ecosystems. Here we explored changes distribution abundance vertebrates response wide range annual hydrologic conditions Mediterranean‐climate California. We conducted wetted vertebrate surveys season 7 years, spanning both extreme wet conditions, size, persistence, configuration habitats relation observed composition fishes, amphibians, reptiles. using k‐means clustering approach, identified three types with distinct connectivity distributions. found some units persisted across all regardless antecedent precipitation, whereas others dried but wettest years. determined persistent pools, subset present stream, supported species even while transient pools acted as important particular life stages, including young‐of‐year minnow Linear mixed models indicated abundances were influenced quantity, quality, connectivity. Our study ‐ considers mosaics uses multi‐year ecological consequences years advance our understanding ecology implications climate change patterns refuge habitat.

Language: Английский

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Three‐Dimensional Subsurface Flow Path Controls on Flow Permanence

Water Resources Research, Journal Year: 2021, Volume and Issue: 57(10)

Published: Sept. 8, 2021

Abstract Intermittent streams currently constitute >50% of the global river network, and number intermittent is expected to increase due changes in land use climate. Surface flows are known expand contract within headwater channel network water table driven by climate, often changing seasonally. However, underlying causes disconnections reconnections throughout stream remain poorly understood may reflect subsurface flow capacity. We assess how 3D flowpaths control local surface at Gibson Jack Creek Rocky Mountains, Idaho, USA. Water dynamics, hydraulic gradients, hyporheic exchange were monitored along a 200‐m section seasonal recession WY2018. Shallow lateral hillslope‐riparian‐stream connectivity was more frequent transects spanning perennially flowing reaches than reaches. During low‐flow periods, larger losing vertical gradients observed paired piezometers adjacent perennial Contrary dominant conceptual models, longitudinal measurements hydrologic both seasonally variable except for one reach that showed consistent significant gains. Observed drying as well pathways, highly even over short distances (30 m). Flow probability capacity upstream locations can be assessed with an outlet hydrograph measurements. Accurate characterization storage, discharge, connection critical understanding drivers cycles their likely responses future change.

Language: Английский

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How do different runoff generation mechanisms drive stream network dynamics? Insights from physics‐based modelling

Hydrological Processes, Journal Year: 2024, Volume and Issue: 38(7)

Published: July 1, 2024

Abstract Non‐perennial river catchments are characterized by an ever‐changing spatial configuration of their flowing streams. A combination empirical data and simplified analytical frameworks has been frequently used in the literature to analyse co‐evolution total active stream length () catchment discharge at outlet (). However, despite increasing availability field data, understanding how runoff generation processes drive spatio‐temporal dynamics non‐perennial reaches remains challenging. In this paper we use CATHY, integrated surface–subsurface hydrological model (ISSHM), investigate impact saturation‐excess (Dunnian) infiltration‐excess (Hortonian) on network two virtual with spatially homogeneous subsurface properties but different morphology. The numerical simulations show that when surface is triggered mechanisms, domain slowly saturated, gradually expands upstream from towards divides. these conditions, specific inflow per unit contributing area relatively uniform along network, thereby implying display a monotonically one‐to‐one relationship. On other hand, mechanisms lead more heterogeneous saturation patterns domain. particular, during wetting phase, Hortonian originate highly transient conditions non‐uniform distribution network. This reflected hysteretic relation marked asymmetry between drying phases event. application ISSHM proved be useful tool elucidate expansion retraction rivers.

Language: Английский

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Analysing river network dynamics and active length - discharge relationship using water presence sensors

Published: March 29, 2021

Abstract. Despite the importance of temporary streams for provision key ecosystem services, their experimental monitoring remains challenging because practical difficulties in performing accurate high-frequency surveys flowing portion river networks. In this study, about 30 electrical resistance (ER) sensors were deployed a high relief 2.6 km2 catchment Italian Alps to monitor spatio-temporal dynamics active network during fall 2019. The set-up ER was personalized make them more flexible deployment field and under low flow conditions. Available data analyzed, compared based estimates nodes' persistency then used generate sequence maps representing reaches stream with sub-daily temporal resolution. This allowed proper estimate joint variations length (L) discharge (Q) entire study period. Our analysis revealed cross-correlation between statistics individual signals persistencies cross sections where placed. observed spatial actively channels also diversity hydrological behaviour distinct zones catchment, which attributed differences geology stream-bed composition. pronounced responsiveness total small precipitation events as led important hysteresis L vs. Q relationship, thereby impairing performances power-law model frequently literature relate these two quantities. Consequently, our site adoption unique L-Q relationship infer variability from discharges would underestimate actual by 40%. work emphasizes potential analysing streams, discussing major limitations type technology emerging specific application presented herein.

Language: Английский

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