Interactive effects of aridity and catchment position on blue-green water partitioning across river networks

Interactive effects of aridity and catchment position on blue-green water partitioning across river networks | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Physical Sciences - Article Interactive effects of aridity and catchment position on blue-green water partitioning across river networks Kyle Brennan, Rose Smith, Gabriel Bowen, Sean Brennan, Renée Brooks, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8595609/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Rainfall received by river basins is partitioned into blue water (surface and groundwater) and green water (soil water used by plants), largely determining how much water is available for terrestrial productivity, aquatic ecosystems, and human water use1,2. Environmental properties, such as aridity, are known to influence blue-green partitioning through evapotranspiration losses to the atmosphere; yet the imprint of climate on the blue–green water cycling within local catchments across river networks remains unknown. Here, we combine stable‑water‑isotope observations with a mass‑balance model for all 20,852 sub-catchments of the Mississippi River Basin and show that climate coupling—defined as the degree to which blue–green water cycling tracks aridity—decreases predictably with river‑network position. Headwaters partitioning fluxes and are more tightly coupled to climate, whereas downstream catchments converge toward similar partitioning states and systematically decouple from aridity. Because the Mississippi River Basin captures ~80% of Earth’s major climate–landform combinations outside tropical and polar extremes, this network‑position scaling provides a transferable constraint on where climate change and water use are most likely to perturb terrestrial water cycling across river basin. Earth and environmental sciences/Hydrology Earth and environmental sciences/Environmental sciences/Environmental impact Earth and environmental sciences/Planetary science/Hydrology Full Text Additional Declarations There is NO Competing Interest. Supplementary Files FV1.1NatureSImrb.pdf SI Cite Share Download PDF Status: Under Review Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8595609","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Physical Sciences - Article","associatedPublications":[],"authors":[{"id":575807261,"identity":"5178ee94-ed1b-4b25-af12-631aab63b9b6","order_by":0,"name":"Kyle 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