Central Plains Water Limited (CPWL) has mapped overland flow paths and depressions across 200,000 hectares in the Selwyn District using high-resolution 1-metre LiDAR from the LINZ Data Portal.

This analysis identifies how water naturally moves across the landscape during rainfall or irrigation, highlighting where it converges, slows or collects.

These features — flow paths and depressions — are powerful tools for targeting environmental mitigation on-farm and within the scheme. By understanding where water concentrates, CPWL and shareholders can prioritise:

  • Riparian planting along direct flow paths to waterways, particularly in erosion-prone areas;
  • Sediment traps or wetland protection in low-lying zones where runoff converges, and
  • Temporary water storage to reduce runoff and promote recharge during heavy rainfall.

This targeted approach ensures interventions are both cost-effective and ecologically impactful.

The data is particularly valuable for winter grazing. Mapping overland flow paths helps farmers avoid placing feed paddocks in areas where water accumulates — reducing the risk of runoff, soil damage and poor animal welfare. Low-lying depressions prone to waterlogging can be excluded from winter plans or protected with mitigation measures like buffer zones or temporary fencing.