Physical Principles of River Basin Flood Control: Decoding Hydrograph Deformation and Active Flow Management

Physical Principles of River Basin Flood Control: Decoding Hydrograph Deformation and Active Flow Management | 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 Physical Principles of River Basin Flood Control: Decoding Hydrograph Deformation and Active Flow Management Yukihiro Shimatani, Tomoko Minagawa, Naoya Furuta, Fumiko Taura, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8759843/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 4 You are reading this latest preprint version Abstract As climate change intensifies extreme rainfall, Nature-based Solutions (NbS) have gained prominence, yet engineering frameworks remain largely empirical and underdeveloped. We propose ten fundamental physical principles of river-basin flood control, grouped into runoff control and inundation-flow control: cover, root reinforcement, infiltration, evaporation and interception, storage, resistance, reverse flow and dispersion, filtering, deflection, and blocking, and we clarify their mechanisms, representative cases, and engineering significance within co-created, basin-wide risk reduction. Analyses of the 2020 Kuma River flood, complemented by evidence from the 2019 East Japan Typhoon (Hagibis) in the Zenpukuji River basin, indicate that the basin-scale runoff-regulating capacity is maintained even under record-breaking rainfall, with no evidence of reaching a plateau. To quantify this behavior, we define the spatio-temporal effective rainwater density ( \(\:{\rho\:}_{ster}={V}_{e}/\:\left(A{\bullet\:T}_{fd}\right)\) ), where \(\:{V}_{e}\) is the time-integrated effective rainfall, \(\:A\:i\) s the catchment area, and \(\:{T}_{fd}\) is the flood duration. On average, peak discharge tends to be lower as \(\:{\rho\:}_{ster}\) decreases; this tendency is probabilistic. Because \(\:{V}_{e}\) is an integral, lowering \(\:{\rho\:}_{ster}\) hinges on enhancing basin loss processes (infiltration, interception, evaporation) and extending \(\:{T}_{fd}\) through physical delay, providing a physical definition of “slowing the flow” and grounding hydrograph deformation in first principles. While modulating \(\:{\rho\:}_{ster}\) reduces peaks on average, it cannot completely prevent flooding under climate change. Therefore, inundation-flow control technologies that dissipate the kinetic energy of floodwaters and conveyed materials—through resistance, reverse flow and dispersion, filtering, deflection, and blocking—are essential, and their effective implementation at scale requires co-creation, a bottom-up process that builds social consensus and pragmatically redefines river-system design boundaries. Nature-based Solutions (NbS) co-creation spatio-temporal effective rainwater density non-saturating basin-scale processes hydrograph deformation flood resilience inundation-flow control engineering framework Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 17 Feb, 2026 Editor assigned by journal 12 Feb, 2026 Submission checks completed at journal 12 Feb, 2026 First submitted to journal 01 Feb, 2026 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-8759843","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":586389856,"identity":"ccb74250-73cf-4c99-9954-c531d9a0dc52","order_by":0,"name":"Yukihiro 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spatio-temporal effective rainwater density, non-saturating basin-scale processes, hydrograph deformation, flood resilience, inundation-flow control, engineering framework","lastPublishedDoi":"10.21203/rs.3.rs-8759843/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8759843/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eAs climate change intensifies extreme rainfall, Nature-based Solutions (NbS) have gained prominence, yet engineering frameworks remain largely empirical and underdeveloped. We propose ten fundamental physical principles of river-basin flood control, grouped into runoff control and inundation-flow control: cover, root reinforcement, infiltration, evaporation and interception, storage, resistance, reverse flow and dispersion, filtering, deflection, and blocking, and we clarify their mechanisms, representative cases, and engineering significance within co-created, basin-wide risk reduction. Analyses of the 2020 Kuma River flood, complemented by evidence from the 2019 East Japan Typhoon (Hagibis) in the Zenpukuji River basin, indicate that the basin-scale runoff-regulating capacity is maintained even under record-breaking rainfall, with no evidence of reaching a plateau. To quantify this behavior, we define the spatio-temporal effective rainwater density (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\rho\\:}_{ster}={V}_{e}/\\:\\left(A{\\bullet\\:T}_{fd}\\right)\\)\u003c/span\u003e\u003c/span\u003e), where \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{V}_{e}\\)\u003c/span\u003e\u003c/span\u003e is the time-integrated effective rainfall, \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:A\\:i\\)\u003c/span\u003e\u003c/span\u003es the catchment area, and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{T}_{fd}\\)\u003c/span\u003e\u003c/span\u003e is the flood duration. On average, peak discharge tends to be lower as \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\rho\\:}_{ster}\\)\u003c/span\u003e\u003c/span\u003e decreases; this tendency is probabilistic. Because \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{V}_{e}\\)\u003c/span\u003e\u003c/span\u003e is an integral, lowering \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\rho\\:}_{ster}\\)\u003c/span\u003e\u003c/span\u003e hinges on enhancing basin loss processes (infiltration, interception, evaporation) and extending \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{T}_{fd}\\)\u003c/span\u003e\u003c/span\u003e through physical delay, providing a physical definition of \u0026ldquo;slowing the flow\u0026rdquo; and grounding hydrograph deformation in first principles. While modulating \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\rho\\:}_{ster}\\)\u003c/span\u003e\u003c/span\u003e reduces peaks on average, it cannot completely prevent flooding under climate change. Therefore, inundation-flow control technologies that dissipate the kinetic energy of floodwaters and conveyed materials\u0026mdash;through resistance, reverse flow and dispersion, filtering, deflection, and blocking\u0026mdash;are essential, and their effective implementation at scale requires co-creation, a bottom-up process that builds social consensus and pragmatically redefines river-system design boundaries.\u003c/p\u003e","manuscriptTitle":"Physical Principles of River Basin Flood Control: Decoding Hydrograph Deformation and Active Flow Management","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-10 11:42:18","doi":"10.21203/rs.3.rs-8759843/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-02-17T11:30:15+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-02-12T06:54:05+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-02-12T06:53:32+00:00","index":"","fulltext":""},{"type":"submitted","content":"Discover Water","date":"2026-02-02T02:57:40+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"discover-water","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"diwa","sideBox":"Learn more about [Discover Water](https://www.springer.com/43832)","snPcode":"","submissionUrl":"","title":"Discover Water","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"56dc9cc0-ab74-4297-9806-08d8ca6e31b3","owner":[],"postedDate":"February 10th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-28T07:54:51+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-10 11:42:18","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8759843","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8759843","identity":"rs-8759843","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}