Spatial Patterns and Drivers of Nonperennial Flow Regimes in the Contiguous United States - IRSTEA - Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (<b>anciennement Cemagref</b>) Accéder directement au contenu
Article Dans Une Revue Geophysical Research Letters Année : 2021

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

John C Hammond
Kendra Kaiser
Sarah E Godsey
Meryl C Mims
Samuel C Zipper
Ryan M Burrows
Walter Dodds
C Nathan Jones
Corey A Krabbenhoft
Kate S Boersma
T. Datry
Julian D Olden
George H Allen
Katie Costigan
Rebecca Hale
Adam S Ward
Daniel C Allen

Résumé

Over half of global rivers and streams lack perennial flow, and understanding the distribution and drivers of their flow regimes is critical for understanding their hydrologic, biogeochemical, and ecological functions. We analyzed nonperennial flow regimes using 540 U.S. Geological Survey watersheds across the contiguous United States from 1979 to 2018. Multivariate analyses revealed regional differences in no-flow fraction, date of first no flow, and duration of the dry-down period, with further divergence between natural and human-altered watersheds. Aridity was a primary driver of no-flow metrics at the continental scale, while unique combinations of climatic, physiographic and anthropogenic drivers emerged at regional scales. Dry-down duration showed stronger associations with nonclimate drivers compared to no-flow fraction and timing. Although the sparse distribution of nonperennial gages limits our understanding of such streams, the watersheds examined here suggest the important role of aridity and land cover change in modulating future stream drying. Plain Language Summary A majority of global streams are nonperennial, flowing only part of the year, and are critical for sustaining flow downstream, providing habitat for many organisms, and regulating chemical and biological processes. Using long-term U.S. Geological Survey measurements for 540 watersheds across the contiguous United States, we mapped patterns and examined the causes of no-flow fraction, the fraction of each climate year with no flow, no-flow timing, the date of the climate year on which the first recorded no flow takes place, and length of the dry-down period, the average number of days from a local peak in daily flow to the first occurrence of no flow. We found differences in patterns of no-flow characteristics between regions, with higher no-flow fraction, earlier timing, and shorter dry-down duration in the western United States. No-flow fractions were greater and less variable in natural watersheds, while no-flow timing was earlier and dry-down duration was shorter in humanmodified watersheds. Aridity had the greatest effect on intermittence across the United States, but unique combinations of climate, biophysical, and human impacts were important in different regions. The number of gages measuring streamflow in nonperennial streams is small compared to perennial streams, and increased monitoring is needed to better understand drying behavior. HAMMOND ET AL.
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Dates et versions

hal-03369194 , version 1 (07-10-2021)

Identifiants

Citer

John C Hammond, Margaret Zimmer, Margaret Shanafield, Kendra Kaiser, Sarah E Godsey, et al.. Spatial Patterns and Drivers of Nonperennial Flow Regimes in the Contiguous United States. Geophysical Research Letters, 2021, 48 (2), pp.e2020GL090794. ⟨10.1029/2020gl090794⟩. ⟨hal-03369194⟩
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