For MODFLOW and PHAST models, ActiveOnLayer(Layer) returns true if the Active data set has a value of true at the current column and row on the specified layer. (In MODFLOW 6 models, it returns True if the IDOMAIN data set has a value greater than 0.) ActiveOnLayer is used in the formula for the UZF_Layer data set in MODFLOW. ActiveOnLayer can only be used when it is being evaluated at cells (MODFLOW) or elements (PHAST). It can not be used when it is being evaluated at nodes in PHAST. In SUTRA models, ActiveOnLayer always returns true. ActiveOnLayer should not be used to set the Z formula of a specified-head boundary.
