To Determine Stream or Watercourse Limits you need:
Topographic - elevation diagram dependent on a national grid of coordinates (EGSA ’87)
Technical Report that proposes the boundaries of the stream and is based on:
Hydrological data - study
Hydraulic components - study
Environmental data - study accompanying this technical report
The polygonal lines that surround the flood lines, the banks of the stream, as well as the physical or technical elements that are part of the stream are defined.