Linear Reservoir (C1 and C2)

The Linear Reservoir model (Model C) is a surface runoff model with minimum data requirements. The runoff computation is based on a comprehensive treatment of hydrological losses (including infiltration) and runoff routing by the linear reservoir principle. Technical details can be found in the MIKE 1D Reference Manual.

MIKE+ includes this model in two versions: C1 and C2. These are variants of the same model, and are used as national standards in the Netherlands and France, respectively.

Linear Reservoir C1 Model Data

 

Figure: The Linear Reservoir C1 Model tab

A full overview of the editor fields and corresponding attributes for the Linear Reservoir C1 model is provided in the table below.

Edit field	Description	Used or required by simulations	Field name in datastructure
Effective Area	Contributing area	Yes	ModelC1EffectiveArea
Use Parameter Set	Reference to a set of model parameters to be used for the current catchment	Yes	ModelC1ParCID
Use Local Parameters	Allows for local use of individual parameters	Optional	ModelC1LocalNo
Time Constant	Local value of the time constant	Optional	ModelC1TimeConst
Init. Loss	Local value of the initial loss	Optional	ModelC1Iloss

Table: Overview of the Linear Reservoir C1 attributes (Table msm_Catchment)

Linear Reservoir C2 Model Data

 

Figure: The Linear Reservoir C2 Model tab

A full overview of the editor fields and corresponding Linear Reservoir C2 model attributes is provided in the table below.

Edit field	Description	Used or required by simulations	Field name in datastructure
Length	Characteristic length of the catchment	Yes	ModelCLength
Slope	Representative slope of the catchment	Yes	ModelCSlope
Imperviousness	Impervious area as a percentage of the actual model area. For values >= 20%, the catchment is an urban catchment. For values < 20%, the catchment is a rural one.	Yes	ModelC2ImperviousArea
Use Parameter Set	Reference to a set of model parameters to be used for the current catchment	Yes	ModelC2ParCID
Use Local Parameters	Allows for local use of individual parameters	Optional	ModelC2LocalNo
Reduction Factor	Local value of the hydrological reduction factor	Optional	ModelC2RedFactor
Init. Loss	Local value of the initial loss	Optional	ModelC2Iloss
Lag Time	Local value of the lag time. If this field is left empty for a catchment defined with local parameters, then a lag time of 5 minutes is used in the simulation	Optional	ModelC2LagTime

Table: Overview of the Linear Reservoir C2 attributes (Table msm_Catchment)

Parameters Linear Reservoir

The Linear Reservoir model uses a number of parameters. For practical reasons, these parameters have been grouped in parameter sets, which, in turn, can be associated with certain catchments. This means the entire model setup can be established with a very small amount of information, while still allowing for full spatial variation of model parameters for individual catchments through the application of local values.

New parameter sets can be inserted and values of individual parameters can be edited in the Parameters Linear Reservoir Editor. This can be activated via Catchments|Parameters Linear Reservoir.

MIKE+ comes with a Default parameter set (-DEFAULT-). The User can insert any number of parameter sets and edit them as needed.

 

Figure: The ‘Parameters linear reservoir’ editor for Dutch and French reservoir models

A full overview of the editor fields and corresponding database attributes is provided in the table below.

Edit field	Description	Used or required by simulations	Field name in datastructure
Parameter Set ID	Parameter set identifier	Yes	MUID
C1/C2	Toggle for editor setting for model C1 and C2, respectively	Yes	-
Initial Loss	Local value of the initial loss	Yes	Iloss
Time Constant	Local value of the time constant	Optional, model C1 only	CTime
Reduction Factor	Local value of the hydrological reduction factor	Optional, model C2 only	RFactor
Lag Time	Local value of the lag time. If this field is left empty, catchments defined with this parameter set will use a lag time of 5 minutes in the simulation	Optional, model C2 only	LagTime
Infiltration	Toggle for switching ON and OFF calculation of infiltration	Optional	InfitrNo
Maximum Horton´s Infiltration Capacity	Maximum infiltration capacity	Optional, if infiltration included	MaxCap
Minimum Horton´s infiltration capacity	Minimum infiltration capacity	Optional, if infiltration included	MinCap
Wet Condition Time Constant	Infiltration time constant for wet conditions	Optional, if infiltration included	WetCond
Dry Condition Time Constant	Infiltration time constant for dry conditions	Optional, if infiltration included	DryCond

Table: Overview of the Linear Reservoir Parameter Set attributes (Table msm_HParC)