Landform Design Slopes and Smoothing

Last Updated: 02 June 2014          For: OptiSurface Designer V1.4 and higher

This article discusses recommended design parameters like slopes and smoothing for your landform designs.

Minimum Slopes:
Dry Areas - 0.05%
Wet Areas - 0.10%
For Drains - can go flatter down to 0.01%

Maximum Slopes:

Rule of Thumb 

  • For furrow irrigated fields, try to make the minimum and maximum slopes as close as possible without increasing the earthworks too much, but there is a trade off there.  We recommend the maximum slopes not more 2x the minimum slopes.
  • For dryland, we've seen analysis that shows slopes over 1% have reduced yield due to runoff, so keeping maximum slopes not more than 1% probably has yield benefits.  The other factor is erosion, especially if the catchment area upstream is large  1% can be too steep.
Recommended Minimum - 100 m/% or 300ft/%

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