Sources and model boundaries — Val-d’Ondine

Operational technology and cyber defense

NIST’s OT security guide describes how controllers, sensors, actuators and supervisory displays interact, with segmentation, incident response and recovery in the context of safety and reliability. NIST SP 800-82 Rev. 3
MITRE ATT&CK for ICS describes limiting communications through segmentation. Val-d’Ondine gives one fictional boundary a selective write filter. Network Segmentation, M0930
An alternate channel can carry reports if the main alarm channel fails. In the game, an independent physical reading, a controller comparison and a functional test answer different questions. Out-of-Band Communications Channel, M0810

The balance between inflow, outflow and storage, which the game reduces to a dimensionless index. USACE HEC-HMS, reservoir modeling concepts
Coordination between a dam operator and emergency authorities, which the game compresses into reports from a fictional emergency operations center. FEMA P-64, Emergency Action Planning for Dams

Water balance: one reservoir index, a constant base inflow and two step-shaped pulses. Real releases depend on head, gate curves and downstream conditions.
Gate deviation: three causes (unapproved logic change, approved travel compensation, actuator fault) produce the same signal. Real diagnosis involves more causes and more evidence.
End of local crew time: the crew sets the gates to minimum release and locks them; the controller takes over only after a tested return. This is an exercise rule, chosen to avoid an unverified handback; real sites define their own safe positions.
Out of scope: interlocks, emergency power, spillway hydraulics, downstream constraints, lockout procedures and post-repair testing.
The Purdue model and IEC 62443 zones are used as vocabulary only. No compliance or real architecture is claimed.

Day, night and aerial scenery: AI-generated illustrations of a fictional dam. They are not photographs of a real installation.
A photograph was consulted during design and is not included: Andrew Parnell, Hoover Dam (aerial view), 30 April 2009, CC BY 2.0. No endorsement is implied. Photograph and credit
Chakra Petch and IBM Plex Mono, SIL Open Font License 1.1, served locally with their notices. Chakra Petch notice
Lucide icons, ISC license, with Feather-derived icons under MIT. React and React DOM, MIT license. Lucide license