Exposure to shallow groundwater in New Zealand's coastal lowlands: what is exposed and why does it matter?

Exposure to shallow groundwater in New Zealand's coastal lowlands: what is exposed and why does it matter? | 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 Exposure to shallow groundwater in New Zealand's coastal lowlands: what is exposed and why does it matter? Zoe Qu, Paula Holland, James Battersby, Matt Dumont, Zeb Etheridge This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9108740/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 6 You are reading this latest preprint version Abstract Climate change is a global challenge for humanity, with sea-level rise and associated groundwater rise posing particular threats to coastal communities. Climate-change-driven sea-level rise is causing groundwater levels to rise in New Zealand’s coastal lowlands (10 meter above current sea level), creating a largely overlooked but significant slow-onset hazard. Progressively shallower groundwater can damage buildings, roads, and underground infrastructure through waterlogging, buoyancy, cracking, and accelerated material degradation. This research uses newly developed national groundwater models and the RiskScape hazard-exposure framework, to estimate building, road, and people exposure to shallow groundwater (within one metre of the surface). Nationally, between 0.5 and 1.7 million buildings, between 7,870 and 35,961 km of roads, and up to 1–3 million population may already be exposed to shallow groundwater. In the coastal lowlands, 83, 548 − 286,859 buildings, 1,368-5,271 km of roads, and between 0.2 and 0.7 million people may already be exposed. Exposure is highest in regions as Canterbury, Auckland, and Waikato, and essential services – including clinics, schools, and lifeline utilities – are also at risk. As New Zealand’s largest city, the Auckland region has the highest estimated replacement cost of buildings and roads exposed to shallow groundwater. Canterbury, and the Bay of Plenty also remain the most highly exposed regions in terms of buildings, roads, and population. This research represents New Zealand’s first essential step towards a national risk assessment of built assets to shallow groundwater by quantifying the baseline exposure today. This baseline underscores the need for future work on vulnerability, damage thresholds, and adaptation strategies. Climate change risk assessment climate change adaptation groundwater rise built assets economic impact assessment Full Text Additional Declarations No competing interests reported. Supplementary Files supportmaterialcoastalexposure.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 14 Apr, 2026 Reviewers agreed at journal 23 Mar, 2026 Reviewers invited by journal 23 Mar, 2026 Editor assigned by journal 22 Mar, 2026 Submission checks completed at journal 16 Mar, 2026 First submitted to journal 12 Mar, 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. 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-9108740","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":611210491,"identity":"b93c2642-3b3c-4d98-a711-a9a59e5b62a5","order_by":0,"name":"Zoe 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Climate-change-driven sea-level rise is causing groundwater levels to rise in New Zealand\u0026rsquo;s coastal lowlands (10 meter above current sea level), creating a largely overlooked but significant slow-onset hazard. Progressively shallower groundwater can damage buildings, roads, and underground infrastructure through waterlogging, buoyancy, cracking, and accelerated material degradation. This research uses newly developed national groundwater models and the RiskScape hazard-exposure framework, to estimate building, road, and people exposure to shallow groundwater (within one metre of the surface). Nationally, between 0.5 and 1.7\u0026nbsp;million buildings, between 7,870 and 35,961 km of roads, and up to 1\u0026ndash;3\u0026nbsp;million population may already be exposed to shallow groundwater. In the coastal lowlands, 83, 548\u0026thinsp;\u0026minus;\u0026thinsp;286,859 buildings, 1,368-5,271 km of roads, and between 0.2 and 0.7\u0026nbsp;million people may already be exposed. 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