During a shore line (coastal) survey for harbour planning, which of the following must be depicted to create a reliable base map?

Introduction / Context:
Shore line surveys provide the positional framework for coastal projects—breakwaters, groynes, and channel alignments. Accurate depiction of coastal boundaries and tidal lines is essential for sediment management and legal demarcation of coastal zones.

Given Data / Assumptions:

• Survey scale sufficient for harbour layout.
• Tidal conditions allow identification of H.W.L. and L.W.L.
• Key landmarks and control points must be recorded.

Concept / Approach:
A comprehensive shore line survey maps the actual shore planform, prominent details (e.g., groynes, outfalls, benchmarks), and tidal limit lines (H.W.L. and L.W.L.). These layers inform setback lines, armour placement elevations, dredging limits, and environmental buffers.

Step-by-Step Solution:
Depict the geometric shore line for plan control.Add prominent onshore details for referencing and construction.Mark H.W.L. and L.W.L. to capture tidal envelopes.Conclude that “All the above” are required.

Verification / Alternative check:
Coastal survey standards prescribe showing both tidal lines and key features to support design and regulatory approvals.

Why Other Options Are Wrong:

• Any subset would leave critical information missing for design and permits.

Common Pitfalls:
Surveying at an unsuitable tidal stage; omitting datum and benchmark references; not recording dynamic features (inlets, spits).

Final Answer:
All the above.