HydPy-WQ-WALRUS (WALRUS default function for calculating catchment outflow)

wq_walrus is a submodel that supplies its main model with discharge estimates. It implements the equation suggested by Brauer et al. (2014) for calculating the outflow of a subcatchment through a ditch or channel, which assumes a rectangular channel geometry and, optionally, the existence of a weir at the channel outlet. See issue 120 for more additional information.

As wq_walrus only applies the single method Calculate_Discharge_V1, we keep the tests short and take a single example from its documentation:

>>> from hydpy.models.wq_walrus import *
>>> simulationstep("12h")
>>> parameterstep("1d")
>>> channeldepth(5.0)
>>> crestheight(2.0)
>>> bankfulldischarge(2.0)
>>> dischargeexponent(2.0)
>>> crestheighttolerance(0.1)
>>> derived.crestheightregularisation.update()
>>> from hydpy import round_
>>> round_(model.calculate_discharge(3.0))
0.111111

class hydpy.models.wq_walrus.Model

Bases: AdHocModel, Base_DischargeModel_V2

HydPy-WQ-WALRUS (WALRUS default function for calculating catchment outflow).

The following interface methods are available to main models using the defined model as a submodel:

• Calculate_Discharge_V1 Calculate the discharge based on the water depth given in m according to Brauer et al. (2014) and return it in mm/T.

DOCNAME: DocName = ('WQ-WALRUS', 'WALRUS default function for calculating catchment outflow')

OBSERVER_METHODS: ClassVar[tuple[type[Method], ...]] = ()

REUSABLE_METHODS: ClassVar[tuple[type[ReusableMethod], ...]] = ()

class hydpy.models.wq_walrus.ControlParameters(master: Parameters, cls_fastaccess: type[FastAccessParameter] | None = None, cymodel: CyModelProtocol | None = None)

Bases: SubParameters

Control parameters of model wq_walrus.

The following classes are selected:

• ChannelDepth() Channel depth [m].

• CrestHeight() The height of the weir’s crest above the channel bottom [m].

• CrestHeightTolerance() Smoothing parameter related to the difference between the water depth and the crest height [m].

• BankfullDischarge() Bankfull discharge [mm/T].

• DischargeExponent() Exponent of the water depth-discharge relation [-].

class hydpy.models.wq_walrus.DerivedParameters(master: Parameters, cls_fastaccess: type[FastAccessParameter] | None = None, cymodel: CyModelProtocol | None = None)

Bases: SubParameters

Derived parameters of model wq_walrus.

The following classes are selected:

• CrestHeightRegularisation() Regularisation parameter related to the difference between the water depth and the crest height [m].