Page 41 - Beaumont Basin Watermaster

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

5.8 Groundwater Recharge

5.8.1 Recharge Package

Groundwater recharge from artificial recharge basins, return flow associated with the various
land use conditions, and infiltration in Noble Creek and Marshall Creek were addressed in the
model using the recharge package. Recharge was applied to the uppermost active model layer
within 29 individual recharge zones (see Figure 35). The relatively large number of recharge
zones was necessary to enable the simulation of changes in return flow and streambed infiltration
over time.

5.8.2 Streamflow Routing Package
San Timoteo Creek streamflow and streambed infiltration were addressed in the model using the
Streamflow Routing Package. This package simulates the interaction between surface streams
and the aquifer based on surface flow measurements in the streambed. The Streamflow Routing
Package was chosen for San Timoteo Creek because inflow to the creek is relatively constant
and, at least recently, has been measured. The Streamflow Routing Package allows for recharge
losses in the stream channels based on measured surface water flow rates and streambed
conductance. Parameters necessary for the input files included the following:

 Stage - surface elevation of the water body (0.3 ft above streambed top);
 Streambed Top - elevation of top of bedding material (assumed to be 1 ft below land
surface elevation);
 Streambed Bottom - elevation of bottom of bedding material (assumed to be 10 ft below
streambed top);
 Stream Width – assumed to be 5 ft;
 Roughness – (model-calculated);
 Streambed Conductance – (model-calculated);
 Inflow (monthly surface water flow rate measured at the canal head);
 Vertical hydraulic conductivity of streambed material (0.44 ft/day).

The streambed conductance was calculated by the model using the following equation:

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