Transient Simulations require: Initial Conditions Storage Coefficient Time step

Types of Initial Conditions Static steady state Dynamic steady state Dynamic cyclic conditions (Time distant conditions)

MODFLOW allows for two types of storage coefficients: Unconfined storage coefficient (i.e., specific yield) Confined storage coefficient

A “convertible” layer in MODFLOW (laycon type 3) is one where cells can convert from confined to unconfined conditions (and back again to confined).

Rule of thumb: take at least five time steps per stress period. MODFLOW divides time into Stress Periods. There are multiple time steps in a stress period. Initial  t Parameters in the following packages can be changed with stress periods: WEL, RCH, RIV, DRN, EVT, GHB

Rule of thumb: take at least five time steps per stress period. MODFLOW divides time into Stress Periods. There are multiple time steps in a stress period. Initial  t

Selecting the time step Can use:  t = Sa 2 /4T for the initial time step of a stress period or find an appropriate time step by trial and error.