Sinuosity of a meandering river — choose the correct definition of sinuosity as used in fluvial geomorphology.

Introduction / Context:
Sinuosity quantifies how much a river meanders relative to the valley or chord line. It is fundamental for river training, navigation, and predicting migration hazards near canals and headworks.

Given Data / Assumptions:

• Two points along a river reach are identified.
• Curved length is measured along the channel centerline (thalweg).
• Straight distance is the valley-line or chord between the same two points.

Concept / Approach:

Sinuosity = (curved channel length) / (straight-line distance). A value greater than 1 indicates meandering; values near 1 indicate near-straight channels. This metric supports decisions on cutoffs, bank protection, and floodplain management.

Step-by-Step Solution:

Verification / Alternative check (if short method exists):

GIS tools can compute centerline length and chord distance directly for rapid sinuosity mapping.

Why Other Options Are Wrong:

Options A and B confuse belt width/river width with the standard definition; E is not the accepted metric; D is incorrect because C is the standard definition.

Common Pitfalls (misconceptions, mistakes):

Using bankline length instead of thalweg; mixing meander-belt width metrics with sinuosity; failing to fix the same endpoints.

Final Answer:

ratio of curved thalweg length to the straight-line distance between the same points