> For the complete documentation index, see [llms.txt](https://docs.therisk.global/organization/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.therisk.global/organization/model/scenarios/storm-surge.md). # Coastal storm surge Coastal storm surge: the coupled risk across water, energy, infrastructure, health and biodiversity, and the applied response of the programme pillars, as a teaching context of the Nexus model. **Where this fits:** water, energy, infrastructure, health and biodiversity · Labs, Foundry, Nexus Universe, Nexus Standards and Nexus Reports · the Nexus Consortium · the whole programme year · teaching context. > Mangroves and dunes absorb the surge; where they are gone, ports, substations and water intakes take it. **In brief.** In this teaching context infrastructure and biodiversity are hit first. 5 of the six sectors are in play through 10 of the fifteen relations, a coupling of 0.64 of the whole system, and the teaching cascade amplifies the initial shock ×2.13. On the response side, 5 of the six pillars apply, with 12 of the eighteen handoffs in play and 8 feedback loops closed. All sector values are **teaching values for a typical city-region, not measurements for any place**; the applications are illustrative and the cited values are published benchmarks, not forecasts.
Two hexagons for coastal storm surge. Left, coupled risk: infrastructure and biodiversity are hit first; 5 of the six sectors (water, energy, infrastructure, health and biodiversity) are in play through 10 of the fifteen relations, and the teaching cascade amplifies the initial shock 2.13 times. Right, applied response: 5 of the six programme pillars apply (Labs, Foundry, Universe, Standards and Reports), with 12 of the eighteen handoffs between them in play and 8 feedback loops closed; the cited headline value is 4 : 1 benefit to cost. Underneath, the eight phases of the programme year in which handoffs happen.

Coupled risk, applied response: coastal storm surge. Left: teaching values for a typical city-region, not measurements. Right: illustrative applications and the measure each pillar answers for; values are published benchmarks (World Bank, Lifelines, 2019; Global Commission on Adaptation, Adapt Now, 2019), not forecasts. Source: the sectors and pillars model published on the GCRI, GRF and GRA home pages, vendored and hash-pinned in tools/figures/vendor/nexus-model. As of 2026-10-21.

Figure data (text alternative) | Element | Kind | Description | Value | | ------------------------------- | ---------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------- | | Water and Energy | Relation in play | Water to energy: cooling water and hydropower (0.6); Energy to water: pumping and treatment (0.5) | 0.55 | | Water and Infrastructure | Relation in play | Water to infrastructure: erosion and flood damage (0.3); Infrastructure to water: pipes, dams and treatment works (0.6) | 0.45 | | Water and Health | Relation in play | Water to health: drinking water and sanitation (0.7); Health to water: utility workforce (0.2) | 0.45 | | Water and Biodiversity | Relation in play | Water to biodiversity: environmental flows (0.6); Biodiversity to water: watershed regulation (0.5) | 0.55 | | Energy and Infrastructure | Relation in play | Energy to infrastructure: power for transport and telecoms (0.8); Infrastructure to energy: transmission and fuel logistics (0.6) | 0.70 | | Energy and Health | Relation in play | Energy to health: hospital power (0.5); Health to energy: grid workforce (0.2) | 0.35 | | Energy and Biodiversity | Relation in play | Energy to biodiversity: pollution from backup fuels (0.2); Biodiversity to energy: biomass (0.1) | 0.15 | | Infrastructure and Health | Relation in play | Infrastructure to health: access to care (0.5); Health to infrastructure: workforce for operations (0.3) | 0.40 | | Infrastructure and Biodiversity | Relation in play | Infrastructure to biodiversity: coastal and river defences (0.2); Biodiversity to infrastructure: storm surge protection (0.2) | 0.20 | | Health and Biodiversity | Relation in play | Health to biodiversity: conservation capacity (0.1); Biodiversity to health: zoonotic spillover and medicines (0.4) | 0.25 | | Water | Sector | depends on infrastructure for pipes, dams and treatment works | stress 0.36 | | Energy | Sector | depends on water for cooling water and hydropower | stress 0.28 | | Infrastructure | Sector | first hit, then depends on energy for power for transport and telecoms | stress 0.79 | | Food | Sector | outside this context | – | | Health | Sector | depends on water for drinking water and sanitation | stress 0.37 | | Biodiversity | Sector | first hit, then depends on water for environmental flows | stress 0.75 | | Amplification | Cascade | Shock 0.6 at Infrastructure and Biodiversity, gain 0.35, 4 rounds; coupling 0.64 of the total | ×2.13 | | F01 | Handoff in play | Universe to Foundry: Admitted mission becomes a cycle project with a decision case | Readiness preparation | | F02 | Handoff in play | Foundry to Universe: Core Build Report and go or no-go evidence | Controlled build | | F03 | Handoff in play | Foundry to Reports: Sealed observations and indicator series behind a profile | Closeout | | F04 | Handoff in play | Universe to Reports: After-action and scenario findings for chapters 10 and 13 | After-action review | | F05 | Handoff in play | Foundry to Reports: National Portfolio movement for chapter 11 | After-action review | | F06 | Handoff in play | Reports to Standards: Method and correction findings as change proposals | Correction | | F07 | Handoff in play | Universe to Standards: Docket items that need a standard or a profile | Docket review | | F08 | Handoff in play | Standards to Foundry: Composed mission profiles and national adoption records | Readiness preparation | | F09 | Handoff | Standards to Academy: Each adopted standard or profile becomes a course module | Renewal | | F10 | Handoff | Universe to Academy: Assessed cycle tasks become completion evidence | Closeout | | F11 | Handoff | Academy to Universe: Qualified participants for the next cycle's roles | Renewal | | F12 | Handoff in play | Reports to Universe: Q4 synthesis informs the next-year mandate | Renewal | | F13 | Handoff in play | Foundry to Standards: Validation and monitoring evidence for conformance review | Controlled build | | F14 | Handoff | Foundry to Academy: Each system's rooms become a learning-by-doing course | Planning | | R1 | Handoff in play | Standards to Reports: Applied in editions | Around the ring | | R2 | Handoff | Reports to Academy: Taught in the open | Around the ring | | R3 | Handoff | Academy to Labs: Questions become experiments | Around the ring | | R4 | Handoff in play | Labs to Foundry: Tested prototypes are built | Around the ring | | Labs | Pillar | Surge model with mangrove and dune buffers | Coast modelled ↑ $80B | | Foundry | Pillar | Coastal twin of ports, substations and water intakes | Assets in the twin ↑ | | Universe | Pillar | Evacuation and port-recovery exercise | Days to reopen port ↓ | | Standards | Pillar | Shared records for coastal assets and defences | Defences recorded ↑ | | Reports | Pillar | Coastal risk profile, built and natural defences | Coast profiled ↑ $390B | | Academy | Pillar | Course for port and coastal managers | Managers qualified ↑ | | Value at risk | Cited value | At least, by households and firms in low- and middle-income countries to infrastructure disruptions. World Bank, Lifelines, 2019 | $390B a year at least, in infrastructure disruption costs to households and firms in low- and middle-income countries | | Return on resilience | Cited value | Net benefit of more resilient infrastructure in developing countries, over the life of the assets. World Bank, Lifelines, 2019 | 4 : 1 benefit to cost | | Avoided loss | Cited value | Coastal flood losses that mangroves already prevent worldwide. Global Commission on Adaptation, Adapt Now, 2019 | $80B flood losses avoided a year | | Planning | Phase (Q1, G0) | F14 Each system's rooms become a learning-by-doing course | 1 handoff(s) | | Readiness preparation | Phase (Q2, G2) | F01 Admitted mission becomes a cycle project with a decision case; F08 Composed mission profiles and national adoption records | 2 handoff(s) | | Controlled build | Phase (Q2, G3) | F02 Core Build Report and go or no-go evidence; F13 Validation and monitoring evidence for conformance review | 2 handoff(s) | | Closeout | Phase (Q3, G5) | F03 Sealed observations and indicator series behind a profile; F10 Assessed cycle tasks become completion evidence | 2 handoff(s) | | After-action review | Phase (Q3) | F04 After-action and scenario findings for chapters 10 and 13; F05 National Portfolio movement for chapter 11 | 2 handoff(s) | | Correction | Phase (Q4) | F06 Method and correction findings as change proposals | 1 handoff(s) | | Docket review | Phase (Q4) | F07 Docket items that need a standard or a profile | 1 handoff(s) | | Renewal | Phase (Q4, G7) | F09 Each adopted standard or profile becomes a course module; F11 Qualified participants for the next cycle's roles; F12 Q4 synthesis informs the next-year mandate | 3 handoff(s) |
## Coupled risk | Sector | In this context | Stress after four rounds | | --------------------------------------------------------------- | ---------------------------------------------------------------------- | ------------------------ | | [Water](/organization/model/sectors/water.md) | Depends on infrastructure for pipes, dams and treatment works | 0.36 | | [Energy](/organization/model/sectors/energy.md) | Depends on water for cooling water and hydropower | 0.28 | | [Infrastructure](/organization/model/sectors/infrastructure.md) | Hit first; then depends on energy for power for transport and telecoms | 0.79 | | [Food](/organization/model/sectors/food.md) | Outside this context | – | | [Health](/organization/model/sectors/health.md) | Depends on water for drinking water and sanitation | 0.37 | | [Biodiversity](/organization/model/sectors/biodiversity.md) | Hit first; then depends on water for environmental flows | 0.75 | Amplification ×2.13; 10 of the 15 relations in play; coupling 0.64 of the total. Teaching values for a typical city-region, not measurements for any place. Coupling is the summed strength of the relations in play, as a share of all fifteen. **What it means for a study.** A coastal storm surge hits infrastructure and ecosystems first. Where mangroves and dunes remain, they absorb the surge; where they are gone, ports, substations and water intakes take it. The context makes the value of natural defences visible as a relation in the model. ## Applied response | Pillar | Illustrative application | Measure it answers for | Better when | Sectors served | | ----------------------------------------------------------------- | ---------------------------------------------------- | ---------------------- | ----------- | ----------------------------- | | [Labs](/organization/programme/labs.md) (applied) | Surge model with mangrove and dune buffers | Coast modelled | higher | Infrastructure, Biodiversity | | [Foundry](/organization/programme/foundry.md) (applied) | Coastal twin of ports, substations and water intakes | Assets in the twin | higher | Water, Energy, Infrastructure | | [Nexus Universe](/organization/programme/universe.md) (applied) | Evacuation and port-recovery exercise | Days to reopen port | lower | Infrastructure, Health | | [Nexus Standards](/organization/programme/standards.md) (applied) | Shared records for coastal assets and defences | Defences recorded | higher | Infrastructure, Biodiversity | | [Nexus Reports](/organization/programme/reports.md) (applied) | Coastal risk profile, built and natural defences | Coast profiled | higher | Infrastructure, Biodiversity | | [Risk Academy](/organization/programme/academy.md) | Course for port and coastal managers | Managers qualified | higher | Infrastructure, Health | **What it means for a response.** The response treats built and natural defences as one system. Labs models the surge with mangrove and dune buffers; the Foundry builds a coastal model of ports, substations and intakes; Universe exercises evacuation and port recovery; Standards records coastal assets and defences in one format; Reports publishes a coastal risk profile. In every case the responsible government, operator or licensed institution decides and acts; the programme informs that decision. ## Published benchmarks | Slot | Value | What it measures | Source | | -------------------- | --------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------- | | Value at risk | $390B a year at least, in infrastructure disruption costs to households and firms in low- and middle-income countries | At least, by households and firms in low- and middle-income countries to infrastructure disruptions | [World Bank, Lifelines, 2019](https://openknowledge.worldbank.org/handle/10986/31805) | | Return on resilience | 4 : 1 benefit to cost | Net benefit of more resilient infrastructure in developing countries, over the life of the assets | [World Bank, Lifelines, 2019](https://openknowledge.worldbank.org/handle/10986/31805) | | Avoided loss | $80B flood losses avoided a year | Coastal flood losses that mangroves already prevent worldwide | [Global Commission on Adaptation, Adapt Now, 2019](https://gca.org/reports/adapt-now-a-global-call-for-leadership-on-climate-resilience/) | Each value is international evidence with its own scope, cited on the same line. None is a forecast for any project or place. See [Method and limits](/organization/model/method-and-limits.md) for how to read the values precisely. ## On the public sites The same context, with the same values, is shown on the [GRA home](https://globalriskalliance.com/) page. ## Related pages [All scenarios](/organization/model/scenarios.md) · [Coupled risk](/organization/model/coupled-risk.md) · [Applied response](/organization/model/applied-response.md) · [Water](/organization/model/sectors/water.md) · [Energy](/organization/model/sectors/energy.md) · [Infrastructure](/organization/model/sectors/infrastructure.md) · [Health](/organization/model/sectors/health.md) · [Biodiversity](/organization/model/sectors/biodiversity.md) ## Sources * World Bank, Lifelines, 2019. * Global Commission on Adaptation, Adapt Now, 2019. * The model data: the "Coupled risk, applied response" section of the [GCRI home page](https://therisk.global/). --- # Agent Instructions This documentation is published with GitBook. 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