Furrow Drainage With 70% Earthworks Saving
Location: KwaZulu-Natal, South Africa
Field Area: 14 ha or 42 acres
Irrigation: Spray Gun Irrigation
This field grew sugarcane on furrows and had drainage problems that was having a dramatic impact on crop yield.
Existing Topography Drainage Analysis
Drainage Analysis with furrows in the direction of the south boundary was calculated. Results show about 21% of the field area suffers ponding with some areas having as much as 0.3m or 1ft ponding water depth.
Single Plane of Best Fit
If a traditional planar design approach was used, landforming will not be feasible - requiring 11,000 m3 of cut volume or 764 m3/ha of earthworks.
An OptiSurface 1Way design was used to calculate the Proposed Surface for the field following the natural lay of the land and thus reducing unnecessary cuts.
OptiSurface 1Way is best for furrow irrigated fields. The main slope was limited to 0.05% to 1.00% and the cross slopes to -0.50% to 0.50%. The smoothing was set to 100m/%.
Proposed Cut/Fill Map
The cut volume required was 2700 m3 or 189m3/ha.
Typical Furrow Profile
OptiSurface saved more than 70% of earthworks compared to traditional planar designs.
Landforming is now feasible for this field allowing the surface drainage problem to be solved and crop yield increased for many years.