PumpLayer(Layer_1, LayerFraction_1, Layer_2, LayerFraction_2, ..., Layer_N, LayerFraction_N)


Note: PumpLayer is only used when linking to MODFLOW.

When a demand site, catchment, or land use branch pumps water from more than one MODFLOW layer, or when Demand Site return flows are injected below ground level, the PumpLayer function allows you to specify how much should be pumped from or injected to each layer. Additionally, the fractions can differ by scenario or change over time. For each layer pumped, include 2 parameters to the PumpLayer function that give the layer number and the fraction pumped from that layer. These fractions are used for every MODFLOW row, column cell that the demand site, catchment, or land use branch is linked to.

Layer_i: The number of the MODFLOW layer from which to pump. Use layer=0 to handle pumping as negative recharge.

LayerFraction_i: The fraction to pump from Layer_i, from 0 to 1.

You do not need to include a layer if there is no pumping from it. The sum of all the LayerFractions for all layers must equal 1. Note: you may not use Interp or other time-series function to specify changes over time. Instead, use the "If" function in conjunction with the "Year" variable. An example below illustrates this.


Pump 50% as negative recharge, 50% from layer 1:

  PumpLayer(0, 0.5, 1, 0.5)

Pump 25% from layer 3 and 75% from layer 4:

  PumpLayer(3, 0.25, 4, 0.75)

Start off pumping 25% from layer 3 and 75% from layer 4, but in 2005 go to 50% from each layer:

  PumpLayer(3, If( Year < 2005, 0.25, 0.5), 4, If( Year < 2005, 0.75, 0.5) )

Read in pump layer fractions from a file:

  PumpLayer( 1, ReadFromFile(LayerFraction.csv, 1), 2, ReadFromFile(LayerFraction.csv, 2) )

See Demand Site Pumping