Page 40 - Beaumont Basin Watermaster

Beaumont Basin Watermaster
2013 Reevaluation of the Beaumont Basin Safe Yield 3-Apr-15

Layer 2 is confined with storage properties of the aquifer defined by specific storage, which is
calculated as the storativity divided by the aquifer thickness. Initial storativity values were
assigned to Layer 2 of the model based on available pumping test data (see Figure 24). For areas
where no pumping test data were available, initial storativity values were assigned based on
Rewis et al. (2006). Final storativity values were developed during model calibration and are
shown on Figure 33.

5.6 Groundwater Pumping

Groundwater pumping was addressed in the model using the well package. Yearly and monthly
groundwater production was input into the model using Visual MODFLOW. Model input files
included the well name, location coordinates, perforation interval(s), and pumping rate. For
wells with screened intervals across multiple layers, Visual MODFLOW apportioned production
to each layer based on the following relationship:

Where:

Q i = Discharge from layer i in a particular well in a given stress period,
Q T = Total well discharge in that stress period,
L i = Screen length in layer i,
Kx i = Hydraulic conductivity in the x-direction in layer i, and
= Sum of the products of screen length and hydraulic conductivities

in the x-direction of all layers penetrated by the well.

5.7 Evapotranspiration

Evapotranspiration loss from the stream channels was addressed using the Evapotranspiration
Package (EVT). The EVT simulates the effects of plant transpiration, direct evaporation, and
seepage at the ground surface. One EVT zone was established for the riparian area along San
Timoteo Creek, as shown on Figure 34.

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