Inferring Trends and Change Attribution Using Regression-Based Unimpaired Runoff to San Francisco Estuary, 1872-2022

Inferring Trends and Change Attribution Using Regression-Based Unimpaired Runoff to San Francisco Estuary, 1872-2022 | 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 Research Article Inferring Trends and Change Attribution Using Regression-Based Unimpaired Runoff to San Francisco Estuary, 1872-2022 Yuchuan Lai, Paul H. Hutton, Sujoy B. Roy This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4499306/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract This work utilized recently extended time series of “unimpaired” or “virgin” runoff from ten Sierra Nevada watersheds upstream of California’s San Francisco Estuary to study long-term hydrologic changes on annual and seasonal time scales. The runoff time series, spanning 1872–2022, were reconstructed using a multivariate regression approach that was informed with monthly temperature and precipitation data. Although the annual runoff series were found to be highly variable and were characterized by multi-year wet and dry periods, they were nevertheless found to be stationary over the full study period. This work also showed that April to July runoff, where snowmelt is a large component, exhibited a statistically significant decrease in most watersheds when reported as a fraction of total annual runoff. A linear trend method revealed statistically significant decreases in this metric in nine watersheds over the period of record; in six watersheds, a piecewise linear trend approach identified significant mid-20th century breakpoints signifying stationary conditions followed by substantial declining trends. The last decade of record showed the highest temperatures and greatest temperature-related declines in this metric. A change attribution analysis suggests that not only are warming temperatures driving runoff timing changes, but they are also impacting annual runoff volumes. This work confirms previous research indicating earlier runoff from snow-fed watersheds in western North America (including California’s Sierra Nevada Mountain range) in recent decades; it also highlights the stationarity in this quantity from the late 19th century to the middle of the 20th century before significant warming trends were apparent. Full Text Cite Share Download PDF Status: Posted 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. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-4499306","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":312823582,"identity":"86d104b3-30ef-4a31-919c-832bc617967e","order_by":0,"name":"Yuchuan Lai","email":"","orcid":"","institution":"Tetra Tech Inc","correspondingAuthor":false,"prefix":"","firstName":"Yuchuan","middleName":"","lastName":"Lai","suffix":""},{"id":312823583,"identity":"a1fe884a-b946-4471-80bb-1fc1fa877d62","order_by":1,"name":"Paul H. Hutton","email":"","orcid":"","institution":"Tetra Tech Inc","correspondingAuthor":false,"prefix":"","firstName":"Paul","middleName":"H.","lastName":"Hutton","suffix":""},{"id":312823584,"identity":"c41651aa-da86-4df6-b9df-bbed3f817d7d","order_by":2,"name":"Sujoy B. Roy","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABEUlEQVRIiWNgGAWjYHCCBGTOATkw+YCwFgMGHgYGxgagYmOwlgR8GiAAoSWxAcNmNCA/I+HhYx6GP3L20oefP/hQcyd9ftjhh0Bb7OR0G3AYfyMh2ZiHwcCYhy/NsHHGsWe5G2+nGQC1JBubHcChRSIhTRqoJbGHh8GwmbfhcO7G2QkgLQcSt+HQAnQYWEt9Dw/7x+a/DYfTDWenf8CrheEGREsCDw+PYTNjw+EEeekc/LYYnHmQbDjHwNiw5wxP4cyeY4cNN0jnFBxIMMDtF/n2nMQHbyrk5Nl72Dd8+FFzWF5+dvrmDx8q7ORwaWFg4Elg4jFAthes0gC7YghgP8D4A8XeBnyqR8EoGAWjYCQCAAlYYeoIXoLSAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0003-2143-7124","institution":"Tetra Tech Inc","correspondingAuthor":true,"prefix":"","firstName":"Sujoy","middleName":"B.","lastName":"Roy","suffix":""}],"badges":[],"createdAt":"2024-05-29 21:48:29","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4499306/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4499306/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":60751192,"identity":"c466eda8-992a-4d9e-8828-4b211d5c6fed","added_by":"auto","created_at":"2024-07-20 20:17:17","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2208676,"visible":true,"origin":"","legend":"","description":"","filename":"CCManuscriptBulletin5MainManuscript5292024.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4499306/v1_covered_6c50200d-a375-434f-bf7a-8e473a94b700.pdf"}],"financialInterests":"","formattedTitle":"Inferring Trends and Change Attribution Using Regression-Based Unimpaired Runoff to San Francisco Estuary, 1872-2022","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-4499306/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4499306/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis work utilized recently extended time series of “unimpaired” or “virgin” runoff from ten Sierra Nevada watersheds upstream of California’s San Francisco Estuary to study long-term hydrologic changes on annual and seasonal time scales. The runoff time series, spanning 1872–2022, were reconstructed using a multivariate regression approach that was informed with monthly temperature and precipitation data. Although the annual runoff series were found to be highly variable and were characterized by multi-year wet and dry periods, they were nevertheless found to be stationary over the full study period. This work also showed that April to July runoff, where snowmelt is a large component, exhibited a statistically significant decrease in most watersheds when reported as a fraction of total annual runoff. A linear trend method revealed statistically significant decreases in this metric in nine watersheds over the period of record; in six watersheds, a piecewise linear trend approach identified significant mid-20th century breakpoints signifying stationary conditions followed by substantial declining trends. The last decade of record showed the highest temperatures and greatest temperature-related declines in this metric. A change attribution analysis suggests that not only are warming temperatures driving runoff timing changes, but they are also impacting annual runoff volumes. This work confirms previous research indicating earlier runoff from snow-fed watersheds in western North America (including California’s Sierra Nevada Mountain range) in recent decades; it also highlights the stationarity in this quantity from the late 19th century to the middle of the 20th century before significant warming trends were apparent.\u003c/p\u003e","manuscriptTitle":"Inferring Trends and Change Attribution Using Regression-Based Unimpaired Runoff to San Francisco Estuary, 1872-2022","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-06-26 14:51:34","doi":"10.21203/rs.3.rs-4499306/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"5aee0d2f-e645-41ed-ae5d-3d6c9efd7be0","owner":[],"postedDate":"June 26th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-07-20T20:09:09+00:00","versionOfRecord":[],"versionCreatedAt":"2024-06-26 14:51:34","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4499306","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4499306","identity":"rs-4499306","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}