Drainage Design Solutions of Different Topographies

Question: 

What is the best approach when designing fields for drainage?

Answer:

Based on our experience designing 100,000s of acres, we have come up with these rules of thumb:
  • Flatter Fields Suit Landforming Alone: On fields with relatively low slopes (e.g. less than 0.5%) then there are often many small shallow depressions. Landforming is generally the best solution as minor cutting and filling can solve the problem most cost effectively.
  • Fields Not Steep and Not Flat Suit Landforming & Drains Combined: Between the flat and steep categories (e.g. 0.5% - 1.0% slope), the solution is generally a combination of ditching and landforming.
  • Steeper Fields Suit Drains Alone: On fields with higher slopes (e.g. greater than 1%), the flows paths are often easily defined and larger deeper depressions may exist. Cutting drains between the depressions is probably the most cost effective solution and putting the cut soil in the depressions can raise the required elevation of the drain network and reduce the total cut volume.
Below are examples of these three different design styles in action.

• Flatter Fields Suit Landforming Alone


Existing Topography


Drainage Analysis


Proposed Topography


Proposed Cut/Fill Map



• Fields Not Steep and Not Flat Suit Landforming & Drains Combined

Existing Topography


Drainage Analysis


Proposed Topography


Ditch Long Section


Ditch Cross Section


Note: Vertical is exaggerated. This example shows a drain channel about 0.8ft deep with 15ft wide flat base that batters up to the surface at 1:20.

Proposed Cut/Fill Map



• Steeper Fields Suit Drains Alone

Existing Topography


Drainage Analysis


Proposed Topography


Note: This complex ditch network is not actually 60ft wide. It was just designed as so to create a flat base to have a reference for the control file.  The scraper will only follow the center line.

Proposed Cut/Fill Map


Main Ditch Long Section




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

Feedback and Knowledge Base