A location-determining receiver (12) collects terrain data within a work area. The terrain data comprises elevation data and corresponding location data. A path planning module (60) or data processor (58) defines a planned path for a drainage channel. The planned path comprises a starting point (30) with first coordinates and a termination point (32) with second coordinates within the work area. The drainage channel extends from the starting point (30) to the termination point (32) such that the starting point (30) has a higher elevation than the termination point (32). A user interface (26) establishes constraint data comprising a minimum cut parameter, a maximum cut parameter, a minimum slope parameter and a maximum slope parameter. A data processor (58) determines a validated path for the planned path or a digging plan based on compliance with the constraint data.
