Regional applicability of Dickens’ flood formula Dickens’ empirical formula for high flood estimation is traditionally considered most applicable to catchments located in which broad region of India?

Introduction / Context:
Historic Indian flood-estimation practice includes regional empirical relations such as Dickens, Ryve’s, and Inglis. Each was developed from data in particular geographic–climatic settings, and their coefficients are intended for those regions absent site-specific gauged records.

Given Data / Assumptions:

• Dickens’ form: Q = C * A^(3/4), with C set from regional experience.
• Use at reconnaissance/preliminary design level, subject to later refinement.

Concept / Approach:

Textbook guidance associates Dickens’ formula primarily with Northern India, whereas Ryve’s is often cited for southern regions and Inglis for certain western/Deccan areas. Applying a formula outside its calibration region without recalibrating C risks bias.

Step-by-Step Solution:

Verification / Alternative check:

Handbooks list Dickens for northern catchments; other formulas are flagged for the south/west, supporting the regional mapping.

Why Other Options Are Wrong:

• Southern/Eastern/Western India: Typically linked to other empirical relations or require recalibrated coefficients.
• Islands: Distinct hydroclimates; Dickens is not specifically intended for them.

Common Pitfalls:

• Using Dickens coefficients unmodified for small urbanized catchments or steep Western Ghats basins.

Final Answer:

Northern India.