The example presented in Figure 13 depicts a water meter (ex:Meter4837QW123). It can be described by a set of static properties either reused from SAREF (e.g., saref:hasModel) or from SAREF4WATR (e.g., s4watr:hasFirmwareVersion). The spatial extent of the meter is described by its geometry (ex:MeterGeom) that is represented as a point in space following its WKT representation. SAREF4WATR defines different measurable properties of a water meter, among them the battery remaining time (s4watr:BatteryRemainingTime) that is the one used in the example. Measurements of the meter for this property can be represented (ex:WMMeasurement200206) using for example the time instant of the measurement, its value and the unit of measure.

Figure 13: Example of water meter

The main function of water meters is to measure water flow. Figure 14 presents two examples of water flow measurements (ex:WFMeasurement170206 and ex:WFMeasurement643234) for two different water flow properties (s4watr:FlowVolume and s4watr:ExternalTemperature, respectively). Notice how the flow volume measurement is described with a time instant while the external temperature one is described with a time interval (ex:PT838452).

Figure 14: Example of water meter measurements

Different tariffs can be applied to water meters. Figure 15 presents an example of a consumption-based tariff (ex:Meter4837QW123Tariff) for a water meter (ex:Meter4837QW123). Different individuals are defined for describing the duration (ex:FiveYears), period (ex:OneYear) and billing period (ex:OneMonth) of the tariff. SAREF4WATR does not restrict how to define particular conditions of a tariff; in the example, for the consumption description a string literal is used.

Figure 15: Example of tariff

The measurement of the different properties of the water itself is also of interest. Figure 16 presents two measurements (ex:DTSMeasurement106 and ex:DTSMeasurement107) of one chemical property (s4watr:Cadmium) and of one bacterial property (s4watr:EscherichiaColi), along with their timestamps, values and units. Even if SAREF4WATR includes a set of predefined water properties, other properties could be defined by instantiating the corresponding s4watr:WaterProperty subclass.

Figure 16: Example of water measurements

Figure 17 depicts a water infrastructure (ex:DowntownDS) that represents a distribution system for drinking water (s4watr:DrinkingWater) intended for domestic use (s4watr:Domestic). The spatial extent of the infrastructure is described by its geometry (ex:DSGeom) that is represented as a polygon in space following its WKT representation. The water distribution system has different subsystems: a water meter (ex:Meter4837QW123), a tank (ex:Tank38472) and a pump (ex:PumpRT73467). These subsystems can be represented through their geometries, as points in the example (ex:MeterGeom, ex:TankGeom, ex:PumpGeom), and different measures could be made of them such as the one depicted (ex:PMeasurement854306) that measures the flow rate (s4watr:FlowRate) of the pump.

Figure 17: Example of water infrastructure and water assets

Figure 18 contains an example of a key performance indicator (ex:MinimumPressureLevel) defined for a water distribution system (ex:DowntownDS). The key performance indicator is defined with its name and calculation period (ex:OneWeek). Besides, an assessment is made for the KPI (ex:MPL2020020723), derived from existing measurements (ex:PLMeasurement56206, ex:PLMeasurement56207 and ex:PLMeasurement56208), indicating the value of the assessment and its temporal properties.

Figure 18: Example of key performance indicator