Global prevalence of non-perennial rivers and streams

Nature, Journal Year: 2021, Volume and Issue: 594(7863), P. 391 - 397

Published: June 16, 2021

Language: Английский

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An overview of the hydrology of non‐perennial rivers and streams

Wiley Interdisciplinary Reviews Water, Journal Year: 2021, Volume and Issue: 8(2)

Published: Feb. 5, 2021

Abstract Non‐perennial rivers and streams are ubiquitous on our planet. Although several metrics have been used to statistically group or compare streamflow characteristics, there is currently no widely definition of how many days over what reach length surface flow must cease in order classify a river as non‐perennial. At the same time, breadth climate geographic settings for non‐perennial leads diversity their regimes, such often quickly they go dry. These rich expanding body literature addressing ecologic geomorphic features, but said be ignored by hydrologists. Yet much we do know about hydrology terms generation processes, water losses, variability flow. We also that while prevalent arid regions, occur across all types experience diverse set natural anthropogenic controls streamflow. Furthermore, measuring modeling these presents distinct challenges, research directions, which still require further attention. Therefore, present an overview current understanding, methodologic knowledge gaps, directions hydrologic understanding rivers; critical topics light both growing global scarcity ever‐changing laws policies dictate whether environmental protection receive. This article categorized under: Science Water >

Language: Английский

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Pervasive changes in stream intermittency across the United States

Environmental Research Letters, Journal Year: 2021, Volume and Issue: 16(8), P. 084033 - 084033

Published: July 29, 2021

Abstract Non-perennial streams are widespread, critical to ecosystems and society, the subject of ongoing policy debate. Prior large-scale research on stream intermittency has been based long-term averages, generally using annually aggregated data characterize a highly variable process. As result, it is not well understood if, how, or why hydrology non-perennial changing. Here, we investigate trends drivers three signatures that describe duration, timing, dry-down period across continental United States (CONUS). Half gages exhibited significant trend through time in at least one signatures, changes no-flow duration were most pervasive (41% gages). Changes substantial for many streams, 7% annual exceeding 100 days during study period. Distinct regional patterns change evident, with widespread drying southern CONUS wetting northern CONUS. These correlated aridity, though spatiotemporal variability diverse signatures. While timing strongly related climate, was watershed land use physiography. Our results indicate conditions increasing prevalence over much binary classifications ‘perennial’ ‘non-perennial’ an accurate reflection this change. Water management should reflect changing nature both today future.

Language: Английский

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Zero or not? Causes and consequences of zero‐flow stream gage readings

Wiley Interdisciplinary Reviews Water, Journal Year: 2020, Volume and Issue: 7(3)

Published: April 13, 2020

Abstract Streamflow observations can be used to understand, predict, and contextualize hydrologic, ecological, biogeochemical processes conditions in streams. Stream gages are point measurements along rivers where streamflow is measured, often infer upstream watershed‐scale processes. When stream read zero, this may indicate that the has dried at location; however, zero‐flow readings also caused by a wide range of other factors. Our ability identify whether or not gage reading indicates dry fluvial system far reaching environmental implications. Incorrect identification interpretation data user lead inaccurate and/or predictions from models analyses. Here, we describe several causes readings: frozen surface water, flow reversals, instrument error, natural human‐driven source losses bypass flow. For these examples, discuss implications interpretations. We highlight additional methods for determining presence, including direct observations, statistical methods, hydrologic models, which applied interpret reach‐ dynamics. Such efforts necessary improve our understand predict activation, cessation, connectivity across river networks. Developing integrated understanding possible meanings zero‐flows will only attain greater importance more variable changing climate. This article categorized under: Science Water > Methods Hydrological Processes Life Conservation, Management, Awareness

Language: Английский

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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

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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

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Spatial Patterns and Drivers of Nonperennial Flow Regimes in the Contiguous United States

Geophysical Research Letters, Journal Year: 2021, Volume and Issue: 48(2)

Published: Jan. 26, 2021

Abstract Over half of global rivers and streams lack perennial flow, understanding the distribution drivers their flow regimes is critical for hydrologic, biogeochemical, ecological functions. We analyzed nonperennial using 540 U.S. Geological Survey watersheds across contiguous United States from 1979 to 2018. Multivariate analyses revealed regional differences in no‐flow fraction, date first no duration dry‐down period, with further divergence between natural human‐altered watersheds. Aridity was a primary driver metrics at continental scale, while unique combinations climatic, physiographic anthropogenic emerged scales. Dry‐down showed stronger associations nonclimate compared fraction timing. Although sparse gages limits our such streams, examined here suggest important role aridity land cover change modulating future stream drying.

Language: Английский

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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

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Intermittent rivers and ephemeral streams: Perspectives for critical zone science and research on socio‐ecosystems

Wiley Interdisciplinary Reviews Water, Journal Year: 2021, Volume and Issue: 8(4)

Published: May 4, 2021

Abstract Intermittent rivers and ephemeral streams (IRES) are now recognized to support specific freshwater biodiversity ecosystem services represent approximately half of the global river network, a fraction that is likely increase in context changes. Despite large research efforts on IRES during past few decades, there need for developing systemic approach considers their hydrological, hydrogeological, hydraulic, ecological, biogeochemical properties processes, as well interactions with human societies. Thus, we assert interdisciplinary promoted by critical zone sciences socio‐ecology relevant. These approaches rely infrastructure—Critical Zone Observatories (CZO) Long‐Term Socio‐Ecological Research (LTSER) platforms—that representative diversity (e.g., among climates or types geology. We illustrate this within French CZO LTSER, including socio‐ecosystems, detail IRES. networks also specialized long‐term observations required detect measure responses climate forcings despite delay buffering effects ecosystems. The LTSER platforms development innovative techniques data analysis methods can improve characterization IRES, particular monitoring flow regimes, groundwater‐surface water flow, biogeochemistry rewetting. provide scientific methodological perspectives which its associated infrastructure would relevant original insights help fill knowledge gaps about This article categorized under: Water Life > Stresses Pressures Ecosystems Science Hydrological Processes Conservation, Management, Awareness

Language: Английский

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Aqua temporaria incognita

Hydrological Processes, Journal Year: 2020, Volume and Issue: 34(26), P. 5704 - 5711

Published: Nov. 18, 2020

It has been 12 years since Bishop et al. (2008) wrote the Invited Commentary "Aqua Incognita: unknown headwaters".They highlighted that "In most regions, overwhelming majority of stream length lies beyond frontiers any systematic documentation and would have to be represented as a blank space on assessment map.This means for streams support aquatic life, understanding is lacking water quality, habitat, biota, specific discharge, or even how many kilometers such are there.This so vast it deserves name help us at least remember there.We propose calling 'Aqua Incognita'" (Bishop al., 2008; p. 1239).We continue agree with this statement need understand headwater better.In commentary, we want draw attention particular type less frequently examined: flow intermittently, i.e., Aqua Temporaria Incognita.Question 3 23 unsolved problems in hydrology (Blöschl 2019) focuses ephemeral dryland streams.We argue focus needs broadening temporary because they ubiquitous all climates.Headwater feed larger perennial particularly sensitive climate change other human influences (Jaeger 2014;Reynolds 2015;Pumo 2016).Their effective management protection, therefore, requires an both natural artificial causes intermittence.Temporary among hydrologically variable systems (Wohl, 2017).They include intermittent seasonally, only response rainfall snowmelt events, episodic contain flowing during

Language: Английский

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