Time BC menu

• General notes on time-dependent boundary conditions
• "Preferences" menu item
• "Soil properties" menu item
• "Edit polygon courses" menu item
• "Delete all" menu item
• "Point potential or source" menu item
• "(Potential or source) In section" menu item
• "Linear (Potential or source)" menu item
• "Linear sources" menu item
• "Diffuse sources" menu item
• "Diffuse sources for soils" menu item
• "Check" menu item
• "Display all polygon courses" menu item
• "Special 1" menu item
• "Special 2" menu item
• "Special 3" menu item
• "Blanket layer water level in section" menu item (for leaky aquifer only)
• "Linear (blanket layer water level)" menu item (for leaky aquifer only)
• "Show (blanket layer water level)" menu item (for leaky aquifer only)