Overview: OptiSurface Circle is a Surface Type designed for pivot irrigated fields where furrows are circular instead of straight.  There are two types - OptiSurface 1Way Circle and OptiSurface 2Way Circle.  As the name suggests, OptiSurface 1Way Circle acts like OptiSurface 1Way but have circular furrows.  Water can drain in one direction along the furrow direction (either clockwise or anti-clockwise).  On the other hand, OptiSurface 2Way Circle can drain in two opposite directions along the circular furrows.  Ridges define the high point while valleys define the cross drains or tail drains.

Displayed by:
Menu: Tools > Landform Design > Surface Type > OptiSurface 1Way Circle or 2Way Circle

Appearance:

Example:
This example plants sugarcane along straight furrows originally in N-S direction.  The client is moving towards circular furrows to minimize the effects of the wheel tracks over the furrows, therefore minimizing ponding in those areas.  They are happy to change the orientation of the road quartering the field to minimize earthworks.

Existing Topography

Google Background Image

As shown in the Background Image, the current layout of the roads quartering the field is not ideal because the lowest area where water will naturally drain in at the NE area near the MB.  As we are planning for circular furrows, we can define the lowest area as the valley zone for the tail drain.

Select OptiSurface Circle 2Way as water can come from both sides of the defined tail drain.  Click Pick then click Pick again to define the tail drain.


Circular Grid Properties

• Main Slope Direction - direction of the fall of the circular furrows which is important for OptiSurface 1Way Circle (no need for OptiSurface 2Way Circle)
• Center Point and Headland - insert the Center Point and Headland Direction or use the Pick Tool.  First click is the center and the second click to show the direction of the taildrain. See image below where the clicks are done for this field.
  

Proposed Topography
The NW and SE cross drains are added valley subzones.  These valley zones are added where the proposed road lies, this results in each quarter having its own tail drain. Q1 drains to NE road, Q2 drains to SE and SW road, Q3 drains to NW road and Q4 drains to NE road.

Proposed Cut/Fill Map