Page 47 - manual_V5_11_9_2018_Html5

• a constant value that does not change with time – select the radio button next to ‘Const:’ and enter
the desired value)
• the aquifer top elevation minus some prescribed value; by default, the stage is set to the aquifer
top elevation, as indicated by the value of zero in the text box next to ‘Top E – ’ shown in Figure
4-13.

Use the text box next to ‘BotE:’ assign a bottom elevation of the source/sink (e.g., the lake bottom
elevation).Use the text box next to ‘Leakance:’ to enter a value (units of day ) for the leakancy (a factor
-1
representing hydraulic conductivity per unit thickness of the land surface).

General Head Dependent flux. Check the box next to “General Head Dependent Flux:’ to assign the zone
as a pollutant/solute source. This requires assigning a source head (entered as a single value in the text box
-1
next to ‘Source head’), the leakancy (units of day ), and the source concentration (units of ppm).

4.2.6 Sources and Sinks (Prescribed)

Click on the ‘Sources and Sinks Prescribed’ tab title to access the Prescribed Flux and Sources sub-menu
(see Figure 4-16). This sub-menu allows for assigning:

• zone-specific recharge as a prescribed flux, steady or unsteady;
• a prescribed head value, steady or unsteady; or
• a source concentration, either as “instantaneous”, continuous or time-varying.

Figure 4-16: Sources and Sinks (Prescribed) sub-menu (for Zone conceptual features).

Prescribed Recharge. Check the radio box next to ‘Recharge:’ and enter a non-zero value (units: inch/year)
in the text box to the right of ‘Recharge:’ to apply a prescribed recharge for all model cells over which the
zone extends. This value is steady (i.e., the same value will be applied for all time-steps if performing
transient simulations).

47