Topographic Controls on the Extension and Retraction of Flowing Streams

Geophysical Research Letters, Journal Year: 2019, Volume and Issue: 46(4), P. 2084 - 2092

Published: Feb. 1, 2019

Abstract Flowing stream networks extend and retract as their surrounding landscapes wet up dry out, both seasonally during rainstorms, with implications for aquatic ecosystems greenhouse gas exchange. Some are much more dynamic than others, however, the reasons this difference unknown. Here we show that tendency of to can be predicted from down‐valley changes in topographic attributes (slope, curvature, contributing drainage area), without measuring subsurface hydrologic properties. Topography determines where water accumulates within valley networks, propose it also modulates flow partitioning between surface subsurface. Measurements 17 mountain support hypothesis, showing undissected heads have greater transport capacities sharply incised valleys downstream. In catchments broad rapidly transition valleys, capacity decreases abruptly, stabilizing length through periods.

Language: Английский

---

Sensitivity of young water fractions to hydro-climatic forcing and landscape properties across 22 Swiss catchments

Hydrology and earth system sciences, Journal Year: 2018, Volume and Issue: 22(7), P. 3841 - 3861

Published: July 19, 2018

Abstract. The young water fraction Fyw, defined as the proportion of catchment outflow younger than approximately 2–3 months, can be estimated directly from amplitudes seasonal cycles stable isotopes in precipitation and streamflow. Thus, Fyw may a useful metric inter-comparison studies that investigate landscape hydro-climatic controls on streamflow generation. Here, we explore how varies with characteristics climatic forcing, using an extensive isotope data set 22 small- to medium-sized (0.7–351 km2) Swiss catchments. We find flow-weighting tracer concentrations streamwater resulted roughly 26 % larger fractions compared corresponding unweighted values, reflecting fact tend when catchments are wet discharge is correspondingly higher. However, flow-weighted strongly correlated each other among They also correlate terrain, soil, land-use indices, well mean measures hydrologic response. Within individual catchments, increase discharge, indicating proportional contribution faster flow paths at higher flows. present new method quantify sensitivity which estimate linear slope relationship between flow. Among sensitivities highly variable only weakly itself, implying these two reflect behaviour differently. Based strong correlations several characteristics, suggest low imply greater persistence proportions fast slow runoff wetness changes. In contrast, high activation different dominant during events, such subsurface tables rise into more permeable layers and/or river network expands further landscape.

Language: Английский

---

Simulation of dynamic expansion, contraction, and connectivity in a mountain stream network

Advances in Water Resources, Journal Year: 2018, Volume and Issue: 114, P. 64 - 82

Published: Jan. 31, 2018

Language: Английский

---

Dynamics of Surface‐Water Connectivity in a Low‐Gradient Meandering River Floodplain

Water Resources Research, Journal Year: 2019, Volume and Issue: 55(3), P. 1849 - 1870

Published: Jan. 24, 2019

Abstract High‐resolution topography reveals that floodplains along meandering rivers in Indiana commonly contain intermittently flowing channel networks. We investigated how the presence of floodplain channels affects lateral surface‐water connectivity between a river and (specifically exchange flux timescales transport) as function flow stage low‐gradient river‐floodplain system. constructed two‐dimensional, hydrodynamic model using Hydrologic Engineering Center's River Analysis System (HEC‐RAS) 2D 32 km (56 river) East Fork White near Seymour, Indiana, USA, lidar elevation data surveyed bathymetry. The was calibrated land‐cover specific roughness to elevation‐discharge from U.S. Geological Survey gage validated against high‐water marks, an aerial photo showing spatial extent inundation, measured velocities. Using results, we analyzed river, patterns pathways, exchange, water residence time on floodplain. Our results highlight bankfull is oversimplified concept for explaining because some stream banks are overtopped major low‐lying inundated roughly 19 days per year. As increased, inundation at higher elevations dissected floodplain, until became fully inundated. Additionally, found driven by bank height or orientation depending conditions. propose conceptual dynamics developed metrics analyze quantitatively complex systems.

Language: Английский

---

Probability of Streamflow Permanence Model (PROSPER): A spatially continuous model of annual streamflow permanence throughout the Pacific Northwest

Journal of Hydrology X, Journal Year: 2018, Volume and Issue: 2, P. 100005 - 100005

Published: Dec. 5, 2018

The U.S. Geological Survey (USGS) has developed the PRObability of Streamflow PERmanence (PROSPER) model, a GIS raster-based empirical model that provides streamflow permanence probabilities (probabilistic predictions) stream channel having year-round flow for any unregulated and minimally-impaired in Pacific Northwest region, annual predictions 2004–2016 at 30-m spatial resolution based on monthly or annually updated values climatic conditions static physiographic variables associated with upstream basin. Predictions correspond to pixel network consistent medium National Hydrography Dataset grid. Total precipitation percent forest cover were consistently most important predictor among global subregional models, which had error rates between 17 22%. Probabilities converted wet dry classes an confidence. Wet classifications used derive descriptors characterize statistical distribution three focal basins. Predicted segments account 52–92% across basins; decreased during climatically drier years. are publicly available through USGS StreamStats platform. Results demonstrate utility PROSPER as tool identifying areas may be resilient sensitive drought conditions, allowing management efforts target protecting critical reaches. Importantly, PROSPER's successful predictive performance can improved new datasets underscoring importance field observations.

Language: Английский

---

Quantifying spatiotemporal variation in headwater stream length using flow intermittency sensors

Environmental Monitoring and Assessment, Journal Year: 2019, Volume and Issue: 191(4)

Published: March 18, 2019

Language: Английский

---

Use of multiple LIDAR-derived digital terrain indices and machine learning for high-resolution national-scale soil moisture mapping of the Swedish forest landscape

Geoderma, Journal Year: 2021, Volume and Issue: 404, P. 115280 - 115280

Published: June 15, 2021

Spatially extensive high-resolution soil moisture mapping is valuable in practical forestry and land management, but challenging. Here we present a novel technique involving use of LIDAR-derived terrain indices machine learning (ML) algorithms capable accurately modeling at 2 m spatial resolution across the entire Swedish forest landscape. We used field data from about 20,000 sites Sweden to train evaluate multiple ML models. The predictor features (variables) included suite generated national LIDAR digital elevation model ancillary environmental features, including surficial geology, climate use, enabling adjustment class maps regional or local conditions. Extreme gradient boosting (XGBoost) provided better performance for 2-class model, manifested by Cohen's Kappa Matthews Correlation Coefficient (MCC) values 0.69 0.68, respectively, than other tested methods: Artificial Neural Network, Random Forest, Support Vector Machine, Naïve Bayes classification. depth water index, topographic wetness 'wetland' categorization derived property were most important predictors all presented enabled generation 3-class with MCC 0.58. In addition classified maps, investigated technique's potential producing continuous maps. argue that probability pixel being as wet can be 0–100% index (dry wet) moisture, resulting could provide more information management

Language: Английский

---

Expansion and contraction of the flowing stream network alter hillslope flowpath lengths and the shape of the travel time distribution

Hydrology and earth system sciences, Journal Year: 2019, Volume and Issue: 23(11), P. 4825 - 4834

Published: Nov. 27, 2019

Abstract. Flowing stream networks dynamically extend and retract, both seasonally in response to precipitation events. These network dynamics can dramatically alter the drainage density thus length of subsurface flow pathways flowing streams. We mapped a small Swiss headwater catchment during different wetness conditions estimated their effects on distribution travel times outlet. For each point catchment, we determined transport distance based surface topography along combined distributions these distances with assumed velocities estimate calculations show that extension retraction substantially change mean time shape distribution. During wet fully extended network, was strongly skewed short times, but as retracted dry conditions, became more uniform. Stream are widely ignored models, our results they need be taken into account when modeling solute interpreting distributions.

Language: Английский

---

What Triggers Streamflow for Intermittent Rivers and Ephemeral Streams in Low‐Gradient Catchments in Mediterranean Climates

Water Resources Research, Journal Year: 2019, Volume and Issue: 55(11), P. 9926 - 9946

Published: Oct. 23, 2019

Abstract Intermittent rivers and ephemeral streams (IRES) account for over 50% of the world's river network are expected to increase with climate change increasing pressure on water resources. One significant challenge better manage IRES is unraveling threshold behavior streamflow generation, by understanding what controls triggers streamflow. This study aimed understand influence groundwater depth, soil hydraulic properties, rainfall generation in IRES, through analyzing spatiotemporal development active areas (where flow processes occurring) determining dominant mechanisms. In a concept‐development approach, we used fully Integrated Surface‐Subsurface Hydrological Models investigate range characteristics representative low‐gradient catchments Mediterranean climates. The results showed that type exerts greatest overall main factor given mechanism contributing processes. identified each demonstrated effect initial head scenarios timing trigger onset. These reaffirm importance unsaturated storage dynamics explain thresholds pathways suggest knowledge prediction mechanisms critical IRES. Future research should identify catchment morphology, geologic constraints, aquifer heterogeneity anisotropy

Language: Английский

---

Intraseasonal Drainage Network Dynamics in a Headwater Catchment of the Italian Alps

Water Resources Research, Journal Year: 2020, Volume and Issue: 56(4)

Published: March 23, 2020

Abstract In the majority of existing studies, streams are conceived as static objects that occupy predefined regions landscape. However, empirical observations suggest stream networks systematically and ubiquitously featured by significant expansion/retraction dynamics produced hydrologic climatic variability. This contribution presents novel data about active drainage network a 5 km 2 headwater catchment in Italian Alps. The has been extensively monitored with biweekly temporal resolution during field campaign conducted from July to November 2018. Our results reveal that, spite wet climate typical study area, more than 70% observed river is temporary, presence disconnected reaches periods. Available have used develop set simple statistical models were able properly reconstruct length function antecedent precipitation. rainfall timing intensity represent major controls on length, while evapotranspiration minor effect intraseasonal changes density. also indicate multiple expansion retraction cycles simultaneously operate at different time scales, response distinct hydrological processes. Furthermore, we found spatial patterns unchanneled lengths related underlying heterogeneity geological attributes. offers insights physical mechanisms driving low‐order alpine catchments.

Language: Английский

---