The Global Centre for Risk and Innovation (GCRI)

Risk Academy, a Nexortium programmeFaculty of Systems and Nexus Studies

Interdependence, cascades, complexity and the water-energy-food-ecosystems nexus

Faculty of Systems and Nexus Studies

Risk that no single owner sees arises between systems: a dry year lowers the river, the turbine spins less, the irrigation canal runs short, the lake floods less and the catch falls.

Open the twin builder See the departments

risksacademy.comsystems-nexusfaculty

Systems and Nexus Studies: departments, disciplines and courses. Drawn as coupled loops.

Open, 3
In preparation, 12
Approved for authoring, 4

From the Academy atlas and the curriculum: primary courses only; numbers mark departments.

Twin builder and simulatorThe Tonle Sap and the Lower Mekong at Phnom Penh5 twin generators, 14 layers, 2 instruments

disciplines in 2 departments: 8
courses open now, 12 in preparation: 3
dams: 14
power plants, 88 MW: 6

Twin figures for the Tonle Sap and the Lower Mekong at Phnom Penh, counted from its layers at their stated dates.

Twin builder and simulator.

The faculty's twin of Tonle Sap on the planet map, the globe and in 3D. Pick a generator, switch layers, run the instruments; every layer prints its provider and date.

The Tonle Sap and the Lower Mekong at Phnom Penh, Cambodia. Flat plan of the same data: the lake and rivers, the dams, the plants by capacity, the cropland and tree cover cells and the numbers below. The 3D twin opens on devices with WebGL once its data and library have been checked; discharge, vegetation, surface water and the annual land cover load in the twin on request, each with its data date.

Terrain 0 to 1,700 m
River 2,956 km
14 dams
6 power plants, 88 MW
Tree cover 37.8 percent of the box
Cropland 39.9 percent of the box
Built-up 0.9 percent of the box
Permanent water 4.7 percent of the box
River discharge, GloFAS via Open-Meteo: live, loads in the twin
Vegetation index, MODIS Terra NDVI 8-day: live, loads in the twin
Surface water extent, OPERA DSWx (HLS): the flood pulse: live, loads in the twin
Land cover classes, MODIS IGBP (annual): live, loads in the twin

Credits and dates per layer are listed under the stage. Relief in the twin is exaggerated ×1.5 for legibility.

Drag to move, right drag or Shift with a drag to turn and tilt, Ctrl with the wheel to zoom. Keyboard: arrows move, Shift with arrows turn and tilt, + and - zoom, 0 resets, V steps through the views, Escape clears.

Flat plan of the same data: the lake and rivers, the dams, the plants by capacity, the cropland and tree cover cells and the numbers below. The 3D twin opens on devices with WebGL once its data and library have been checked; discharge, vegetation, surface water and the annual land cover load in the twin on request, each with its data date.

System-dynamics loop simulator

A stock-and-flow loop of the basin's four systems: river inflow fills a reservoir you size, its release turns a turbine, feeds irrigation on the cropland share WorldCover measured, and reaches the lake, whose flooded area drives a fish-catch index; six parameters on screen, twelve monthly steps, the stocks plotted and the summary in the table.

Move a parameter and the loop recomputes in your browser. The inflow is the plan's probe value at the Kratie cell (15,416 m3/s on 2026-10-17) held flat; in the twin, press Build the seasonal pulse for one archive request (daily GloFAS discharge since 1984) and the twelve monthly means replace it. Fixed teaching constants: turbine efficiency 0.85; the flooded area ranges from the permanent water to 3 times it.

Reservoir storage5 km3

Release per month40 percent of the stock

Hydraulic head50 m

Irrigated share of the cropland20 percent

Irrigation demand120 mm per month

Flow at two thirds of the flood range12000 m3/s

Catch exponent1 power

Flat inflow 25,200 GWh over the year, flooded area 8,435 to 8,600 km2, 0 months of irrigation shortfall (teaching model).

Reading	Value
Inflow	flat 15,416 m3/s, the plan's probe value (GloFAS model output, never a warning)
Energy over the year	25,200 GWh (mean turbine power 2,875 MW; the box's plants total 88 MW, 12 MW of it hydropower, 2021 snapshot)
Irrigation	100 percent of demand met on average; 0 months of shortfall
Flooded area	8,435 to 8,600 km2 (permanent water 3,533 km2 from WorldCover 2021)
Catch index	2.43 on average (1 = the permanent water alone; a shape, never a catch)
Water per person downstream	4,073 m3 per person per month over 9,725,580 people (WorldPop 2020, Cambodian part of the box)
Reservoir at year end	5 km3 of the 5 km3 you set

A teaching model of coupled stocks after Forrester and Sterman, with the hydropower equation P = rho g Q H eta; not a model of any operator's reservoir, of the Mekong River Commission's or of the lake's measured hydrology. Every parameter is a learner input shown on screen; the inflow is GloFAS model output, or the plan's probe value until the archive is built. A teaching model of coupled stocks on learner parameters, not any operator's reservoir. GloFAS is a model, never a flood warning; the catch index is a shape, never a catch. Method: Forrester, J. W. (1961), Industrial Dynamics, MIT Press; Sterman, J. D. (2000), Business Dynamics: Systems Thinking and Modeling for a Complex World, McGraw-Hill; the hydropower equation after Gulliver, J. S. and Arndt, R. E. A. (1991), Hydropower Engineering Handbook, McGraw-Hill.

Cascade propagation across water, energy, food and ecosystems

Perturb one system (a drought year, a release rule change, a crop failure) and trace the response of the other three step by step through a coupling matrix: its default entries are the loop simulator's own sensitivities, computed at build by finite differences, and you can scale or edit the couplings; the spectral radius says whether the cascade damps or amplifies.

The matrix reads A[affected][cause]: the water column holds the loop simulator's own sensitivities at its default parameters, computed at build by a 10 percent change (energy 0.89, food 0, ecosystems 0.32; food to water -0.02); the three declared couplings and the strength are yours to set. Choose a perturbation and read the state of each system over eight steps; the spectral radius says whether the cascade damps or amplifies.

Energy to food0.2 elasticity

Food to ecosystems-0.15 elasticity

Ecosystems to water0.1 elasticity

Coupling strength1 times

Drought year after 8 steps: water -31 percent, energy -27 percent, food -5 percent, ecosystems -9 percent; spectral radius 0.21 (damped; an estimate by power iteration; a teaching model, not a prediction).

Affected by cause	water	energy	food	ecosystems
water	0	0	-0.02	0.1
energy	0.89	0	0	0
food	0	0.2	0	0
ecosystems	0.32	0	-0.15	0

Step	water, percent change	energy, percent change	food, percent change	ecosystems, percent change
step 1	-30	0	0	0
step 2	-30	-27	0	-10
step 3	-31	-27	-5	-10
step 4	-31	-28	-5	-9
step 5	-31	-27	-6	-9
step 6	-31	-27	-5	-9
step 7	-31	-27	-5	-9
step 8	-31	-27	-5	-9

A linear teaching model on a learner-edited matrix, x(t+1) = A x(t) + u, after the interdependency typology of Rinaldi, Peerenboom and Kelly and the input-output form of Leontief; the couplings are sensitivities of a teaching loop, not measured couplings of the basin, and nothing here is a prediction. A linear teaching model on a learner-edited matrix; the couplings are not measured. Not a prediction for the basin. Method: Rinaldi, S. M., Peerenboom, J. P. and Kelly, T. K. (2001), Identifying, understanding, and analyzing critical infrastructure interdependencies, IEEE Control Systems Magazine 21(6), 11-25; Leontief, W. (1986), Input-Output Economics, 2nd edition, Oxford University Press.

The map loads from this site as it nears the view (MapLibre 6.9.1, checked by hash).

What the faculty teaches.

On the Tonle Sap and the Lower Mekong the stage carries a system-dynamics loop after Forrester and Sterman with the hydropower equation and a cascade after Rinaldi, Peerenboom and Kelly whose spectral radius says whether a shock damps or grows, on Copernicus terrain, OpenStreetMap rivers and dams, ESA WorldCover and GloFAS discharge, under ISO 31000:2018 and the Sendai Framework. A graduate can scope a water-energy-food nexus system and propagate a perturbation through it with every parameter on screen.

Faculty of Systems and Nexus Studies groups 8 disciplines into 2 departments. 3 of the 15 courses whose primary discipline is here are open for enrolment and the rest are in preparation; all of them are taught on the Risk Academy main site, so your record stays in one place.

2 departments, 8 disciplines.

Numbered as on the faculty figure at the top of the page. Each card counts the department's disciplines and the courses whose primary discipline is there.

Disciplines by status.

Each discipline once, in its department. A mark is one primary course, filled when it is open.

Where the field is moving.

Emerging areas, the technologies changing practice and the bodies that set the field's methods, from the faculty's expert review. Named for orientation; none of them endorses the Academy.

What is changing now.

The newest developments cited on the faculty's discipline pages, sources checked on 16 October 2026. Each links to its discipline and its source.

The faculty hub.

News and research as they are published, per discipline, with the faculty's other tools.

The newest research, preprints, news and humanitarian reports for 8 disciplines, each with its source and date, load here. Open the research and news hub

Systemic, compound and cascading risk, Complex systems and systems modelling, Global catastrophic risks, Tipping points and resilience of Earth and social systems, Supply network and economic contagion, Nexus-Based Risk Management (NRM), Water-energy-food-ecosystems nexus, Polycrisis and global risk assessment

Where to start, and where it leads.

The faculty's entry course, then its flagship pathways and the Academy flagship in Nexus-Based Risk Management.

3 open, 12 in preparation.

Courses with their primary discipline in this faculty. Open courses link to the catalogue; the others are listed so you can plan.

The standards it teaches toward.

The Nexus Standards subsites whose standards the faculty's disciplines teach, by the Academy's proposed mapping.

Where these subjects are practised.

Where the faculty practises.

Lab	What you do in it	Courses using it
Network lab	Build dependency graphs, find critical nodes, trace cascades	3
Map lab	Read hazard, exposure and boundaries on real maps	1

Nexus programmes that span faculties.

Each programme joins disciplines from more than one faculty and is hosted by an institute on the main site; it is listed on every faculty it spans.

Nexus-Based Risk ManagementSystemic risk and infrastructureApplies systemic risk methods to interdependent lifelines.2 disciplines in 2 faculties

Institutes that convene the faculty.

Institute

Institute for Nexus-Based Risk Management

The institute is the cross-faculty home of Nexus-Based Risk Management, the Academy's paradigm.

Terms used on this page.

Around Faculty of Systems and Nexus Studies.

Faculty of Systems and Nexus Studies

Start in one department.

Each department lists its disciplines, courses and pathways; each discipline its scope, labs, technology and key terms.

Open Department of Systemic Risk and Complexity Browse the course catalogue