3.4.7.1 Subzones

Last Updated: 29 July 2020         For: OptiSurface Designer V2+


Overview:
 
Subzones can apply different design parameters to different areas within a boundary zone. Where a subzone exists and parameters are defined, that value will overwrite the design parameters of the boundary zones. The design parameters are mapped onto the calculation grid points that fall within that subzone. Subzones can overlap each other. Where they overlap, their ranking in the priority list defines which design parameter is actually sent to the OptiSurface Calculation Engine.

These settings tell the OptiSurface Calculation Engine what characteristics or properties the proposed design surface should have.

Displayed by:
Menu: Tools > New Design Zone

Toolbar:

Or

 

Appearance:


Zone Name:  If you don't want the subzone to be exported out to the control files, just put a minus symbol (-) in front of the name e.g. "-S1"
Zone Colour: Click the color bar and change the color of the subzone.
Turn OFF:  Tick ON to turn the subzone OFF so the subzone parameters will have no effect on the next landform design calculation.


Subzone Type

  • Normal:  This is the default subzone type when you draw a subzone. It can apply different design parameters to the calculation grid points that fall within that subzone. For more details on the parameters, see 3.4.7 Landform Design.
  • Valley:  This is a special type of subzone used to guide water to flow to a desired direction. It can also apply different design parameters. Note: The valley subzone should extend to just outside the boundary zone. Only effective when used OptiSurface 2Way and OptiSurface 4Way.

  • Ridge:  This is a special type if subzone that behaves like a barrier, preventing water to flow to the subzone. It can also apply different design parameters. Note: The ridge subzone should ideally extend to just outside the boundary zone and go back from one side of the boundary to the other to work well. Only effective when used OptiSurface 2Way and OptiSurface 4Way.

  • Exclusion:  Points inside this subzone are not included in the calculation of the landform design. OptiSurface treats this area as a boundary, therefore allows drainage into the subzone.

  • Inflow: Used for Runoff Analysis. Adds an inflow from a watershed going into the field.
Example

The design below shows an OptiSurface 2Way surface type. Ridge (red) and Valley (blue) subzones were added to define the high spots and low spots of the field.

The valley subzones represent the infield drains and is recommended to be perpendicular (or approach a perpendicular) to the Main Slope direction. In cases where the infield drain will be parallel to the Main Slope direction, an Exclusion (pink) subzone can be used instead of a valley zone. 

Finally, the brown subzones are Normal subzones with the Smoothing Distanced ticked ON and reduced compared to the boundary so cuts are reduced on those areas.

See below the initial landform design calculation.



There are no points inside the pink Exclusion subzone. A surface is generated inside only because of the adjacent points triangulating.



The Valley subzones fall into the Exclusion Zone treating it as boundary.



Then it's just a matter of adding the breakline as the center line of the drain then battering it up to create the drain channel. See the long sections and cross sections below.





Subzone Parameters

  • Max. Cross/Main Slope Ratio: Defines the ratio of cross slope to main slope of any calculation grid point covered by the subzone.

  • Max. Allowable Elevation (m or ft): Defines the maximum elevation of any calculation grid point covered by the subzone.
  • Min. Allowable Elevation (m or ft): Defines the minimum elevation of any calculation grid point covered by the subzone.

  • Min. Cut (m or ft): Defines the minimum depth of soil that can be removed (cut) from any grid point covered by the subzone.
  • Max. Cut (m or ft): Defines the maximum depth of soil that can be removed (cut) from any grid point covered by the subzone.
  • Min. Fill (m or ft): Defines the minimum depth of soil that can be removed (cut) from any grid point covered by the subzone.
  • Max. Fill (m or ft): Defines the maximum depth of soil that can be added (filled) an any grid point covered by the subzone.


Subzone Net Earthworks

  • Balance Earthworks:  Ticking this will balance the earthworks within the subzone when Fill to Import and Cut to Export are set to zero. Note: The earthworks within the boundary zone is the master balance for the boundary and any balancing within subzones are nested within the boundary. For example, if the boundary zone balances to zero import or export but a subzone has an import of 1000 m3 then the areas outside the subzone but inside the boundary will contribute 1000 m3 of cut into the subzone. So, the subzone is like a sub-balance as well, i.e. it is not a separate balance.

  • Fill to Import (m3 or yd3):  Defines the volume of soil to bring into the subzone boundary area to the field boundary area. This volume is taken into account when balancing earthworks to the cut/fill ratio.

  • Fill to Export (m3 or yd3):  Defines the volume of soil to remove from the subzone boundary area to the field boundary area. This volume is taken into account when balancing earthworks to the cut/fill ratio.


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