> 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/sectors/water.md). # Water Water in the Nexus model: what the sector gives to energy, food, health, infrastructure and biodiversity, what it depends on, and the teaching contexts in which it is hit first. **Where this fits:** water (W) and the sectors it couples to · Labs, Foundry and Nexus Universe · GCRI (evidence and methods) · Planning and readiness preparation · model page. **In brief.** Water sits at the top of the hexagon because more relations start from it than from any other sector. It gives irrigation to food (the strongest relation in the teaching set, 0.8), drinking water and sanitation to health (0.7), cooling water and hydropower to energy (0.6) and environmental flows to ecosystems (0.6). It depends in turn on the pipes, dams and treatment works of infrastructure (0.6) and on power for pumping and treatment (0.5). Water is hit first in three of the eight teaching contexts: urban flood, hydropower reservoir and drought. All strengths on this page are **teaching values for a typical city-region, not measurements for any place**. ## What the sector carries Water is both a resource and a hazard. As a resource it is drawn, treated, stored and returned; as a hazard it arrives as flood, storm surge or its absence in drought. The model treats both through the same relations: a flood damages the infrastructure that treats water, and a drought removes the water that cools power plants. This dual character is why water management is the first of the five adaptation areas the Global Commission on Adaptation costs ([2019](https://gca.org/reports/adapt-now-a-global-call-for-leadership-on-climate-resilience/)), and why the water-energy-food nexus approach begins with water ([FAO, 2014](https://www.fao.org/4/bl496e/bl496e.pdf)). ## What water gives Read from water to the sector it supports, strongest first. | To | Strength | Through | | --------------------------------------------------------------- | -------- | ----------------------------- | | [Food](/organization/model/sectors/food.md) | 0.8 | irrigation | | [Health](/organization/model/sectors/health.md) | 0.7 | drinking water and sanitation | | [Energy](/organization/model/sectors/energy.md) | 0.6 | cooling water and hydropower | | [Biodiversity](/organization/model/sectors/biodiversity.md) | 0.6 | environmental flows | | [Infrastructure](/organization/model/sectors/infrastructure.md) | 0.3 | erosion and flood damage | ## What water depends on Read from the sector it depends on, strongest first. | From | Strength | Through | | --------------------------------------------------------------- | -------- | ------------------------------- | | [Infrastructure](/organization/model/sectors/infrastructure.md) | 0.6 | pipes, dams and treatment works | | [Energy](/organization/model/sectors/energy.md) | 0.5 | pumping and treatment | | [Biodiversity](/organization/model/sectors/biodiversity.md) | 0.5 | watershed regulation | | [Food](/organization/model/sectors/food.md) | 0.3 | withdrawals and runoff | | [Health](/organization/model/sectors/health.md) | 0.2 | utility workforce | ## Teaching contexts The contexts in which water is in play, whether hit first or reached through the coupling, with its stress after four rounds of the teaching cascade. | Context | Role of this sector | Stress after four rounds | How the sectors fail together | | ------------------------------------------------------------------- | ---------------------------- | ------------------------ | ------------------------------------------------------------------------------------------------------------------------ | | [Urban flood](/organization/model/scenarios/urban-flood.md) | Hit first | 0.86 | Flooded streets take out substations, pumping stations and clinic access together; drinking water fails when power does. | | [Hydropower reservoir](/organization/model/scenarios/hydropower.md) | Hit first | 0.68 | A dam stores water for power and flood control, and reshapes the river's sediment, fish passage and wetlands downstream. | | [Drought](/organization/model/scenarios/drought.md) | Hit first | 0.72 | Low river flows cut irrigation, cooling water and hydropower at once; food prices, nutrition and ecosystems follow. | | [Heatwave](/organization/model/scenarios/heatwave.md) | Reached through the coupling | 0.21 | Cooling demand peaks the grid while rivers warm; heat stress fills hospitals and wilts crops. | | [Grid blackout](/organization/model/scenarios/blackout.md) | Reached through the coupling | 0.21 | Without power, water treatment, telecoms, cold chains and hospitals fall back on fuel that runs out. | | [Coastal storm surge](/organization/model/scenarios/storm-surge.md) | Reached through the coupling | 0.36 | Mangroves and dunes absorb the surge; where they are gone, ports, substations and water intakes take it. | ## Observing the sector [**Nexus of Observatories**](/organization/systems.md)**.** Every Nexus platform and system includes its own observatory capability, covering remote sensing, in-situ instruments and edge deployments. Across every area where these observatories are implemented, they form the Nexus of Observatories, part of the not-for-profit programme architecture. The GCRI site describes the capability on its [Observatory](https://therisk.global/ecosystem/observatory/) page. What the observatories record about water, and under what terms, is set for each country in its National Model and its profile scope agreement. Records follow the [Nexus Standards](/organization/institutions/nexus-standards.md) published on [nexustandards.com](https://nexustandards.com/standards/), whose text and status govern. ## International frameworks | Framework | What it governs or shows | Source | | ---------------------------------------- | -------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------- | | Sendai Framework | Targets on reducing direct economic loss and damage to critical infrastructure, including water supply | [2015](https://www.undrr.org/publication/sendai-framework-disaster-risk-reduction-2015-2030) | | FAO water-energy-food nexus | Governs water, energy and food as interdependent systems, with trade-off assessment and cross-sector policy dialogue | [2014](https://www.fao.org/4/bl496e/bl496e.pdf) | | IRENA, renewable energy in the WEF nexus | Quantifies water use in energy supply and energy use in water and food supply chains | [2015](https://www.irena.org/publications/2015/Jan/Renewable-Energy-in-the-Water-Energy--Food-Nexus) | | Early Warnings for All | Multi-hazard early warning for floods and droughts, by the end of 2027 | [2022](https://www.un.org/en/climatechange/early-warnings-for-all) | | IPBES nexus assessment | Interlinkages between water, biodiversity, food and health, and response options that reduce trade-offs | [2024](https://www.ipbes.net/nexus-assessment) | ## Deeper reading in this documentation [Water systems (thesis)](/organization/organization/architecture/i.-thesis/vi.-water-systems.md) · [Future of Water (guild)](/organization/cooperation/nexus-guilds/future-of-water.md) ## Sources * United Nations (2022). Early Warnings for All initiative, launched by the UN Secretary-General on 23 March 2022; Executive Action Plan 2023–2027 (WMO, 2022). * FAO (2014). The Water-Energy-Food Nexus: A new approach in support of food security and sustainable agriculture. Rome: Food and Agriculture Organization of the United Nations. * IPBES (2024). Summary for Policymakers of the Thematic Assessment Report on the Interlinkages among Biodiversity, Water, Food and Health (Nexus Assessment). IPBES/11/12/Add.1. Bonn: IPBES secretariat. doi:10.5281/zenodo.13850289. * IRENA (2015). Renewable Energy in the Water, Energy and GCRI Food. Abu Dhabi: International Renewable Energy Agency. * UN General Assembly (2015). Sendai Framework for Disaster Risk Reduction 2015–2030. A/RES/69/283, 3 June 2015. * 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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