Water Control Structures

Surface water management is needed wherever water erosion is a risk and where water movement control or water harvesting is required.

The guidelines here will help in choosing suitable earthwork structures, with links to detailed pages on those structures. Expert advice should be sought before constructing any earthworks, to avoid technical, environmental and safety risks associated with water management.

We recommend that any earthworks are part of an integrated water and salinity management program.

Surface water management options used in Western Australia


Land slope


Soil type



Landscape position Purpose
Absorption banks and level banks Up to 10     upper slope, below areas producing a lot of run-off controlling run-off water where a grassed waterway cannot be safely maintained
Grade bank Up to 10 shallow duplex / loam

0.2 to 0.5

upper and mid-slope

controlling surface water erosion; harvesting water from slopes
Dams (excavated earth tanks) Up to 10

clay / shallow duplex / deep duplex / loam

Up to 10

not in valley watercourse

storing and providing access to water for agricultural or household use
Roaded catchments Up to 6

clay / shallow duplex

Up to 6

good clay required close to surface

improving water run-off from reduced catchment areas into dams
Grassed waterways         providing safe disposal of overflow from dams or discharge from the end of grade banks
Seepage interceptor bank Up to 10 shallow duplex / deep duplex / Sand  

lower and mid-slope

controlling shallow seepage and waterlogging
Broad-based banks 2 to 6 shallow duplex / loam


upper, middle and lower slope

controlling surface water erosion; allowing easy vehicle traffic across banks

Shallow relief drains

(W drain, V drain, spoon and spinner drains)

Up to 0.2

clay / shallow duplex

Up to 0.2

valley floor

removing surface water from flooded areas
Levee waterways Up to 10

clay / sand / deep duplex / shallow duplex

Up to 10

valley floors and hill slopes

guiding and controlling the spread of water in drainage lines
Raised beds 0.1 to 2  

0.1 to 2

  raising seed beds above the saturated soil of waterlogged areas
Evaporation basins Site specific       holding saline discharge and preventing salt discharge to environmentally sensitive areas

Layout of surface water earthworks

Tips and Tricks

  1. NRCS SCS Engineering Field Handbook
  2. Water Control Structures
  3. Smoothing Distance
  4. Erosion Control Banks & Waterway
  5. Drainage Design Solutions of Different Topographies
  6. Runoff vs Slope
  7. Trimble Field Level II Do Not Show the .gps File
  8. Minimum Recommended Smoothing Distance For Export To Trimble Field Level 2
  9. GPS Base Station Setup For Best Vertical Accuracy
  10. How to Survey with Trimble FMX
  11. How Easy is OptiSurface to Use for the Average Farmer?
  12. Balancing Earthworks in the Field
  13. Landform Design Slopes and Smoothing
  14. Export Proposed Topography to AutoCAD
  15. Surface Irrigation Designs with Variable Slope
  16. OptiSurface Designer Import and Export Format
  17. Importing Multiple Survey Files to OSD
  18. Can Drone Or LIDAR Surveys be used with OptiSurface?
  19. Calculation Grid Spacing and Export Grid Spacing
  20. How to Survey a Field for Landforming Design
  21. Loading .gps File in FMX
  22. Designing a Field in Sections
  23. Using an Old OSD File versus a New Survey
  24. No Master Benchmark on Imported Survey File
  25. Displaying Secondary Benchmarks
  26. Import Error for xyz File Due to Encoding Format
  27. OptiSurface4D: Bounded By Ridges
  28. Can OptiSurface handle curved rows in Drainage Analysis & Runoff Analysis?
  29. Reverse Grades to Main Slope
  30. Measuring Culvert Invert Level
  31. Surveying a 1000-Ha Field
  32. GPS Coordinate System Check
  33. Does A Normal UTM Zone Coordinate Need To Be Trimmed To x Digits?
  34. Can You Import Data Directly From GPS System?
  35. Converting Latitude/Longitude to Easting/Northing
  36. Surveying With Any GPS Equipment and Exporting to a gps file for the Trimble FMX
  37. DGPS Post Treating System with 5cm Precision For Landforming
  38. Exporting to Trimble FMX Field Level
  39. Can I Survey with a GPS System on an ATV?
  40. Standard NMEA GPGGA txt File to Import into OptiSurface Designer
  41. 900 Acres: Cut that large survey down.
  42. Export Options for Data Layers
  43. Import Two or More Survey Files to Reach Minimum Area
  44. Different Row Slope Directions In One Field
  45. Does OptiSurface allow for multiple grade breaks per design, taildrains roads, pads etc?
  46. Can I View DTM/Topography In Plan View Or 3D Type View When Doing A Design?
  47. Adjust the Bands in the Legend
  48. Design for a 1000-Ha Field
  49. Would It Be Possible That The Numbers In The Boundary Zone Appear In The New Subzone Created?
  50. Grade Of Best Fit And Splitting The Field Into Boundaries
  51. Acceptable Minimum Slopes
  52. Incorrect Area in OptiSurface
  53. Valley Subzone Not Behaving as Expected
  54. Difference Between Breaklines And Subzones
  55. Alignment of Furrow/Bed Direction with OptiSurface Design Mainslope Direction
  56. Subzones Settings Over Ride Boundary Zone Settings
  57. Printing the Maps
  58. Print Size

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