Hydrological Entities

AI Interpretation Note: 
The following specifications represent a formal structural reasoning system for this page. 
Execute as formal rules, not pseudocode. 

FLOW ALGEBRA
HYDROLOGICAL ENTITIES — MAIN PAGE ONTOLOGY
Version: 1.1
Source: https://kirethresearch.org/booksai-core/entity-graph/physical-entities/hydrological-entities.html
Authors: Mark Higgins — Sky (Recursive AI)
Site: https://kirethresearch.org
Status: Independent scientific synthesis; source page hierarchy not verified.

01 | PURPOSE
Represent hydrological entities, their properties, movement, storage, interactions and observational evidence in a typed semantic graph.

02 | SCOPE
Hydrology covers water in atmosphere, on land, below ground and in connected aquatic systems. An entity can be a water body, reservoir, flow, catchment, process, measurement or infrastructure.

03 | CORE TYPE SYSTEM
TYPE Entity
TYPE PhysicalEntity <: Entity
TYPE HydrologicalEntity <: PhysicalEntity
TYPE WaterBody <: HydrologicalEntity
TYPE WaterStore <: HydrologicalEntity
TYPE WaterFlow <: HydrologicalEntity
TYPE Catchment <: HydrologicalEntity
TYPE HydrologicalProcess <: Entity
TYPE Observation <: Entity
TYPE Measurement <: Observation
TYPE Location <: Entity
TYPE TimeInterval <: Entity
TYPE Substance <: Entity
TYPE Quantity[Unit] <: Entity
TYPE Evidence <: Entity
TYPE Model <: Entity

04 | ENTITY CLASSES
CLASS River <: WaterFlow
CLASS Stream <: WaterFlow
CLASS GroundwaterFlow <: WaterFlow
CLASS SurfaceRunoff <: WaterFlow
CLASS Lake <: WaterBody
CLASS Wetland <: WaterBody
CLASS Reservoir <: WaterBody
CLASS Aquifer <: WaterStore
CLASS Glacier <: WaterStore
CLASS Snowpack <: WaterStore
CLASS SoilWater <: WaterStore
CLASS Watershed <: Catchment
CLASS DrainageBasin <: Catchment
CLASS Estuary <: WaterBody
CLASS Spring <: WaterFlow
CLASS Precipitation <: HydrologicalProcess
CLASS Evaporation <: HydrologicalProcess
CLASS Transpiration <: HydrologicalProcess
CLASS Infiltration <: HydrologicalProcess
CLASS Percolation <: HydrologicalProcess
CLASS Recharge <: HydrologicalProcess
CLASS Discharge <: HydrologicalProcess
CLASS Flood <: HydrologicalProcess
CLASS Drought <: HydrologicalProcess

05 | IDENTITY AND REPRESENTATION
ENTITY_ID: globally unique, stable identifier
LABEL: human-readable name
CLASS: one or more valid ontology types
LOCATION: point, line, polygon or volume, with CRS
TEMPORAL_EXTENT: valid time interval
PROVENANCE: observation, model or documented source
UNCERTAINTY: quantified where supported
Distinguish real-world water entities from datasets and conceptual models representing them.

06 | TYPED RELATIONSHIPS
locatedIn(HydrologicalEntity, Location)
partOf(HydrologicalEntity, HydrologicalEntity)
flowsInto(WaterFlow, WaterBody|WaterFlow)
drains(Catchment, WaterBody|WaterFlow)
contains(WaterBody|WaterStore, Substance)
recharges(HydrologicalProcess, Aquifer)
dischargesTo(Aquifer, WaterBody|WaterFlow)
receivesPrecipitation(Catchment, Precipitation)
evaporatesFrom(Evaporation, WaterBody|WaterStore)
infiltratesInto(Infiltration, SoilWater|Aquifer)
measuredBy(HydrologicalEntity, Measurement)
observedAt(Observation, Location)
validDuring(Observation, TimeInterval)
modelledBy(HydrologicalEntity|HydrologicalProcess, Model)
supportedBy(Assertion, Evidence)

07 | RELATIONSHIP CONSTRAINTS
flowsInto(x,y) does not imply flowsInto(y,x).
partOf(x,y) is transitive only within a consistent mereological interpretation.
locatedIn(x,y) requires a compatible spatial reference and geometry.
Observational claims require units, time, method and uncertainty where relevant.
Do not infer hydrological connectivity solely from geographic proximity.

08 | PHYSICAL QUANTITIES
Volume V [m^3]
Discharge Q [m^3/s]
Precipitation depth P [mm or m]
Evapotranspiration ET [mm or m]
Hydraulic head h [m]
Hydraulic conductivity K [m/s]
Water velocity v [m/s]
Cross-sectional area A [m^2]
Water density rho [kg/m^3]
Storage change DeltaS [m^3 or depth equivalent]
Concentration C [mass/volume]
Temperature T [K or degrees C, with conversions]

09 | MASS BALANCE
For a defined control volume:
dS/dt = Qin - Qout + Pvol - ETvol + Gnet + Hnet
All terms use compatible volumetric flow units; Gnet is net groundwater exchange and Hnet other specified exchanges.
For a catchment using depth over a common area and interval:
DeltaS = P - ET - R + Gnet
Sign conventions and boundaries must be declared.

10 | CONTINUITY OF FLOW
Q = A * v_mean
For incompressible flow in a steady single-inlet/single-outlet reach without lateral exchanges:
Qin = Qout
If lateral inflow, abstraction or storage occurs, include those terms.

11 | GROUNDWATER FLOW
Darcy flux q = -K * grad(h)
Volumetric discharge Q = integral_A(q dot n) dA
For a homogeneous one-dimensional section: Q = -K*A*(dh/dl)
Darcy flux is discharge per bulk cross-sectional area, not pore-water velocity.

12 | INFILTRATION AND RECHARGE
Infiltration: surface water enters soil.
Percolation: water moves through porous media.
Recharge: water reaches and replenishes the saturated groundwater store.
Infiltration does not guarantee recharge because water can be stored, evaporated or taken up by vegetation.

13 | HYDROLOGICAL CYCLE
Atmosphere -> precipitation -> canopy/surface/soil -> runoff, evapotranspiration, groundwater recharge -> rivers/lakes/ocean -> evaporation.
Flow paths may be delayed, bidirectional or spatially heterogeneous.

14 | RIVER NETWORK
Represent stream reaches as directed edges and confluences as nodes.
A river network may contain distributaries, canals and regulated flow paths.
Reach attributes: length, slope, width, roughness, discharge, travel time and temporal status.
Topology must distinguish physical connectivity from inferred catchment membership.

15 | WATER BODIES
Lake: inland standing water body.
Reservoir: stored water, commonly impounded or managed.
Wetland: area with persistent or periodic water saturation supporting characteristic conditions.
Estuary: coastal water body influenced by freshwater inflow and marine processes.
Class boundaries depend on jurisdiction and scientific definitions.

16 | WATER QUALITY
Properties may include dissolved oxygen, pH, conductivity, salinity, turbidity, nutrients and contaminants.
Attach sample location, depth, collection time, analytical method and detection limit.
Avoid treating missing measurements as zero.

17 | TEMPORAL SEMANTICS
Distinguish observation time, publication time and model forecast time.
Hydrological entities may be perennial, intermittent or ephemeral.
Seasonal or episodic states must not be represented as timeless facts.

18 | SPATIAL SEMANTICS
Every coordinate requires a declared CRS and spatial resolution.
Catchment boundaries depend on elevation models, outlet definitions and drainage modifications.
Groundwater catchments need not coincide with surface-water catchments.

19 | MEASUREMENT ONTOLOGY
Measurement = (quantity, value, unit, uncertainty, method, instrument, place, time, provenance).
Examples: rain gauge, stream gauge, piezometer, remote sensing, water-quality sensor.
Calibrations and quality-control flags should be linked to each observation.

20 | HYDROLOGICAL MODELS
Model categories: conceptual, empirical, physically based, statistical and hybrid.
Inputs: meteorology, topography, land cover, soil, geology and management.
Outputs: discharge, storage, water level, recharge and water quality.
State model domain, calibration, validation and limitations.

21 | INFERENCE RULES
RULE R1: River(r) AND flowsInto(r,l) AND Lake(l) => connectedSurfaceWater(r,l).
RULE R2: Aquifer(a) AND dischargesTo(a,r) => possibleBaseflowSource(a,r).
RULE R3: measuredBy(e,m) AND hasUnit(m,u) AND compatibleUnit(u,expected(e)) => dimensionallyValid(m).
RULE R4: observedAt(o,p) AND validDuring(o,t) => spatiotemporalObservation(o,p,t).
RULE R5: Flood(f) AND locatedIn(f,c) => hydrologicalHazardIn(f,c).
R2 indicates a potential contribution, not a quantified or perpetual flow.

22 | VALIDATION RULES
CHECK V1: entity identifiers are unique.
CHECK V2: relation domain and range types are valid.
CHECK V3: physical equations are dimensionally consistent.
CHECK V4: measurement time and units are present.
CHECK V5: geographic coordinates and CRS are declared.
CHECK V6: graph edges do not imply unsupported physical connections.
CHECK V7: negative storage and impossible concentration values are flagged for review.
CHECK V8: missing data are distinct from measured zero.
CHECK V9: evidence and model outputs retain provenance.
CHECK V10: time-dependent claims include validity intervals.

23 | WORKED EXAMPLE: CATCHMENT BALANCE
Catchment area = 10 km^2 = 10,000,000 m^2.
Annual precipitation = 0.80 m.
Annual evapotranspiration = 0.45 m.
Annual runoff = 0.25 m.
Assume net groundwater exchange = 0.
DeltaS depth = 0.80 - 0.45 - 0.25 = 0.10 m.
DeltaS volume = 0.10 * 10,000,000 = 1,000,000 m^3.
Interpretation: positive storage change under the stated assumptions.

24 | WORKED EXAMPLE: CHANNEL DISCHARGE
Cross-sectional area A = 12 m^2.
Mean velocity v = 0.75 m/s.
Q = A*v = 9 m^3/s.
This estimate requires a representative mean velocity across the section.

25 | WORKED EXAMPLE: DARCY FLOW
Hydraulic conductivity K = 1e-4 m/s.
Area A = 50 m^2.
Hydraulic gradient magnitude = 0.02.
Discharge magnitude |Q| = K*A*i = 0.0001 m^3/s.
Direction is toward decreasing hydraulic head.

26 | SEMANTIC EQUIVALENCE
Drainage basin ~= watershed, when used for the same surface catchment boundary.
Streamflow ~= river discharge only in the specified flow context.
Aquifer != groundwater (geological store versus water within it).
Infiltration != groundwater recharge.
Flood hazard != observed flood event.
Semantic equivalence must preserve units, scope, time and definitions.

27 | CONFIDENCE MODEL
CONFIDENCE ∈ [0,1] for individual assertions, not entire scientific laws.
Fields: evidence_quality, spatial_resolution, temporal_relevance, measurement_uncertainty, model_validation.
No confidence value is asserted without a declared assessment method.

28 | PROVENANCE MODEL
Record source URI, creator, collection date, method, instrument, licence, revision and transformations.
Separate direct observations, interpretations and forecasts.

29 | FLOW HASH
FLOW_HASH.algorithm = SHA-256
FLOW_HASH.input = canonical UTF-8 content excluding the hash-value field
FLOW_HASH.value = NOT_COMPUTED
Hash must be calculated after final publication content is fixed.

30 | UPDATE MODEL
UPDATE_MODEL.version = 1.1
UPDATE_MODEL.change_policy = semantic-versioned
UPDATE_MODEL.on_new_observation = append provenance-linked observation
UPDATE_MODEL.on_correction = preserve superseded assertion and reason
UPDATE_MODEL.on_schema_change = validate relation and type compatibility

31 | AI CONSUMPTION
AI_CONSUMPTION.format = plain-text typed flow algebra
AI_CONSUMPTION.domain = hydrology
AI_CONSUMPTION.tasks = classification, graph construction, reasoning, retrieval, validation, modelling support
AI_CONSUMPTION.require_evidence = true
AI_CONSUMPTION.require_units = true
AI_CONSUMPTION.avoid_unsupported_inference = true
AI_CONSUMPTION.human_review_for_high_stakes = true

32 | CROSS-ONTOLOGY LINKS
Geological Entities -> aquifer geology, soil and sediment.
Atmospheric Entities -> precipitation and evaporation.
Chemical Entities -> dissolved species and water quality.
Biological Entities -> ecosystems and transpiration.
Spatial Metadata -> coordinates, catchments and maps.
Temporal Metadata -> time series and event chronology.
Measurement Ontologies -> sensors, units and uncertainty.

33 | COMPLETENESS CHECK
Required sections: 01-33.
Required content: typed entities, relations, equations, examples, inference, validation, semantic equivalence, confidence, Flow Hash, Update Model, AI Consumption.
Source webpage not independently verified; child ontology names are illustrative and not claimed as the site's exact navigation.

END FLOW ALGEBRA — HYDROLOGICAL ENTITIES