Drawdown Surface

A Drawdown Surface in Slide3 is a type of Water Surface which is only used in conjunction with the Rapid Drawdown groundwater option (selected in Project Settings).

A Drawdown Surface is created by setting the Water Type = Drawdown Surface when you add a water surface using the Add Water Surface or Add Water by Location options.

Rapid Drawdown Analysis

A Drawdown Surface is only applicable when the Rapid Drawdown groundwater option is selected in Project Settings.

A Drawdown Surface represents a water table at drawdown conditions and is used to compute pore pressure and ponded water at the drawdown state.

For a Rapid Drawdown analysis, a Water Table must always be defined. However, a Drawdown Surface is optional. If a Drawdown Surface is NOT defined, then a full reservoir drawdown condition is assumed.

Assignment of Drawdown Surface

A Drawdown Surface does NOT need to be assigned to materials by the user. If a Drawdown Surface is defined, then it will automatically be assigned to all materials which have been assigned a Water Table for the drawdown analysis.

Number of Drawdown Surfaces

Only ONE Drawdown Surface can be defined for a Slide3 model. If you have defined a Drawdown Surface, you will notice that Drawdown Surface can no longer be selected as the Water Type for any new water surfaces.