Modelling phosphorus inputs and dynamics in a large tropical semiarid basin

Modelling phosphorus inputs and dynamics in a large tropical semiarid basin | 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 Modelling phosphorus inputs and dynamics in a large tropical semiarid basin Iran Eduardo Lima Neto This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5083369/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 04 Mar, 2025 Read the published version in Environmental Science and Pollution Research → Version 1 posted 4 You are reading this latest preprint version Abstract This study proposed a simple process-based model to predict total phosphorus (TP) inputs and dynamics in a large tropical semiarid basin in Brazil (19,015 km²), where the Castanhão dam, the largest non-hydropower reservoir in Latin America, is located. The model solved on a monthly basis the water balance and TP dynamics along the river system, considering complete mixing at the cross-section, steady-state regime and a piston-type transport with first-order decay. Both primary and secondary data were used to validate the model, with deviations of up to about 20%. A linear increase in the flow rate along the river was observed, indicating that transmission gains were dominant. TP concentration increased with river flow rate and a consistent decay along the system was observed. TP from point-sources (PS) was assumed constant. TP from non-point sources (NPS) decreased with time (R² = 0.90) due to the continuous wash-off process. NPS was the dominant load, decreasing respectively from 99 to 61% of the total load from high to low flows. TP load varied from 1-141 ton/month, with an average of 34 ton/month. This resulted in an average TP yield of 21.2 kg km -2 year -1 , which is significantly lower than the national average due to the peculiarities of the region: lower precipitation, intermittent rivers and high-density reservoir network. All the simulated TP values were above the mandatory limit of 0.05 mg/L. PS reduction was only effective for relatively low flows, while NPS reduction was the most relevant remediation measure for both high and low flows. The impact of climate change on TP concentration also yielded TP > 0.05 mg/L for all the projected scenarios, with the input loads to the Castanhão reservoir spanning from 23 to 266 ton/month. The proposed model can also be applied to other regions with different hydroclimatic conditions and land uses. hydroclimatic conditions land use modelling non-point source point source phosphorus load Full Text Cite Share Download PDF Status: Published Journal Publication published 04 Mar, 2025 Read the published version in Environmental Science and Pollution Research → Version 1 posted Reviewers agreed at journal 17 Nov, 2024 Reviewers invited by journal 17 Nov, 2024 Editor invited by journal 11 Nov, 2024 First submitted to journal 11 Nov, 2024 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. 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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-5083369","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":379111546,"identity":"4e6e8322-93cc-46bb-9c71-b00e6afa6818","order_by":0,"name":"Iran Eduardo Lima Neto","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAuElEQVRIiWNgGAWjYBACNhDxgY0hAUwzMBwgTgvjDIgWxhlEaQEBZh6StPBJH3722KbMJo+/gcew4QfDnXzCDuNLMzfOOZdWLHGAx7Cxh+GZZQNBLTwMZtK5bYcTGw7wmD9mYDhsQNgWHvZv0pZt/xPnA21pJlILj5k0Y9uBxA2kaCmT7DmXnLjxMFthY4/BM8Ja5HvYt0n8KLNLnHe8eWPDj4o7hLUgADOIIEXDKBgFo2AUjALcAACypTdXVNkIvgAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0001-8612-5848","institution":"Federal University of Ceara: Universidade Federal do Ceara","correspondingAuthor":true,"prefix":"","firstName":"Iran","middleName":"Eduardo Lima","lastName":"Neto","suffix":""}],"badges":[],"createdAt":"2024-09-13 11:16:45","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5083369/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5083369/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s11356-025-36181-1","type":"published","date":"2025-03-04T15:56:56+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":78190975,"identity":"9ca4bd9c-fdaf-410e-a647-d3e5527a954a","added_by":"auto","created_at":"2025-03-10 19:52:00","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":500515,"visible":true,"origin":"","legend":"","description":"","filename":"Manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5083369/v1_covered_7bb7d5b9-66c4-4d05-be5d-fac48c51c127.pdf"}],"financialInterests":"","formattedTitle":"Modelling phosphorus inputs and dynamics in a large tropical semiarid basin","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"environmental-science-and-pollution-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"espr","sideBox":"Learn more about [Environmental Science and Pollution Research](https://www.springer.com/journal/11356)","snPcode":"11356","submissionUrl":"https://submission.nature.com/new-submission/11356/3","title":"Environmental Science and Pollution Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"hydroclimatic conditions, land use, modelling, non-point source, point source, phosphorus load","lastPublishedDoi":"10.21203/rs.3.rs-5083369/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5083369/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study proposed a simple process-based model to predict total phosphorus (TP) inputs and dynamics in a large tropical semiarid basin in Brazil (19,015 km\u0026sup2;), where the Castanh\u0026atilde;o dam, the largest non-hydropower reservoir in Latin America, is located. The model solved on a monthly basis the water balance and TP dynamics along the river system, considering complete mixing at the cross-section, steady-state regime and a piston-type transport with first-order decay. Both primary and secondary data were used to validate the model, with deviations of up to about 20%. A linear increase in the flow rate along the river was observed, indicating that transmission gains were dominant. TP concentration increased with river flow rate and a consistent decay along the system was observed. TP from point-sources (PS) was assumed constant. TP from non-point sources (NPS) decreased with time (R\u0026sup2; = 0.90) due to the continuous wash-off process. NPS was the dominant load, decreasing respectively from 99 to 61% of the total load from high to low flows. TP load varied from 1-141 ton/month, with an average of 34 ton/month. This resulted in an average TP yield of 21.2 kg km\u003csup\u003e-2\u003c/sup\u003e year\u003csup\u003e-1\u003c/sup\u003e, which is significantly lower than the national average due to the peculiarities of the region: lower precipitation, intermittent rivers and high-density reservoir network. All the simulated TP values were above the mandatory limit of 0.05 mg/L. PS reduction was only effective for relatively low flows, while NPS reduction was the most relevant remediation measure for both high and low flows. The impact of climate change on TP concentration also yielded TP\u0026thinsp;\u0026gt;\u0026thinsp;0.05 mg/L for all the projected scenarios, with the input loads to the Castanh\u0026atilde;o reservoir spanning from 23 to 266 ton/month. The proposed model can also be applied to other regions with different hydroclimatic conditions and land uses.\u003c/p\u003e","manuscriptTitle":"Modelling phosphorus inputs and dynamics in a large tropical semiarid basin","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-11-19 05:28:06","doi":"10.21203/rs.3.rs-5083369/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2024-11-18T01:03:51+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-11-17T18:20:41+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"Environmental Science and Pollution Research","date":"2024-11-12T04:07:16+00:00","index":"","fulltext":""},{"type":"submitted","content":"Environmental Science and Pollution Research","date":"2024-11-11T20:58:00+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"environmental-science-and-pollution-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"espr","sideBox":"Learn more about [Environmental Science and Pollution Research](https://www.springer.com/journal/11356)","snPcode":"11356","submissionUrl":"https://submission.nature.com/new-submission/11356/3","title":"Environmental Science and Pollution Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"2cfbb288-1943-47e1-89cc-83203b8fb50e","owner":[],"postedDate":"November 19th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-03-10T19:51:55+00:00","versionOfRecord":{"articleIdentity":"rs-5083369","link":"https://doi.org/10.1007/s11356-025-36181-1","journal":{"identity":"environmental-science-and-pollution-research","isVorOnly":false,"title":"Environmental Science and Pollution Research"},"publishedOn":"2025-03-04 15:56:56","publishedOnDateReadable":"March 4th, 2025"},"versionCreatedAt":"2024-11-19 05:28:06","video":"","vorDoi":"10.1007/s11356-025-36181-1","vorDoiUrl":"https://doi.org/10.1007/s11356-025-36181-1","workflowStages":[]},"version":"v1","identity":"rs-5083369","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5083369","identity":"rs-5083369","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}