Global prevalence of non-perennial rivers and streams

Nature, Год журнала: 2021, Номер 594(7863), С. 391 - 397

Опубликована: Июнь 16, 2021

Язык: Английский

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

Wiley Interdisciplinary Reviews Water, Год журнала: 2021, Номер 8(2)

Опубликована: Фев. 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 >

Язык: Английский

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Pervasive changes in stream intermittency across the United States

Environmental Research Letters, Год журнала: 2021, Номер 16(8), С. 084033 - 084033

Опубликована: Июль 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.

Язык: Английский

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

Wiley Interdisciplinary Reviews Water, Год журнала: 2020, Номер 7(3)

Опубликована: Апрель 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

Язык: 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, Год журнала: 2021, Номер 404, С. 115280 - 115280

Опубликована: Июнь 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

Язык: Английский

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Quantifying spatiotemporal variation in headwater stream length using flow intermittency sensors

Environmental Monitoring and Assessment, Год журнала: 2019, Номер 191(4)

Опубликована: Март 18, 2019

Язык: Английский

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

Geophysical Research Letters, Год журнала: 2021, Номер 48(2)

Опубликована: Янв. 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.

Язык: Английский

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

Water Resources Research, Год журнала: 2020, Номер 56(4)

Опубликована: Март 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.

Язык: Английский

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

Wiley Interdisciplinary Reviews Water, Год журнала: 2021, Номер 8(4)

Опубликована: Май 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

Язык: Английский

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Topographic, soil, and climate drivers of drought sensitivity in forests and shrublands of the Pacific Northwest, USA

Scientific Reports, Год журнала: 2020, Номер 10(1)

Опубликована: Окт. 28, 2020

Abstract Climate change is anticipated to increase the frequency and intensity of droughts, with major impacts ecosystems globally. Broad-scale assessments vegetation responses drought are needed anticipate, manage, potentially mitigate climate-change effects on ecosystems. We quantified sensitivity in Pacific Northwest, USA, as percent reduction greenness under droughts relative baseline moisture conditions. At a regional scale, shrub-steppe ecosystems—with drier climates lower biomass—showed greater than conifer forests. However, variability was considerable within biomes mediated by landscape topography, climate, soil characteristics. Drought generally areas higher elevation, bulk density. Ecosystems high included dry forests along ecotones shrublands, Rocky Mountain subalpine forests, cold upland sagebrush communities. In valley bottoms low density available water capacity showed reduced sensitivity, suggesting their potential refugia. These regional-scale drought-sensitivity patterns discerned from remote sensing can complement plot-scale studies plant physiological help inform climate-adaptation planning conditions intensify.

Язык: Английский

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