Question

High drainage density is representative of a terrain with

• A. high relief
• B. arid climate
• C. impermeable surface layer
• D. permeable surface layer

Answer 1

The Correct Option is A, C

Factors Influencing Drainage Density 

Step 1: Evaluating the Given Factors

• (A) High relief → High drainage density: Correct. Areas with **high relief** have **steep slopes**, which cause water to flow rapidly and form a **dense drainage network** due to increased erosion and runoff.
• (B) Arid climate: Incorrect. **Arid climates** generally have **low drainage density** because of **scarce precipitation** and **limited surface runoff**, leading to poorly developed drainage systems.
• (C) Impermeable surface layer: Correct. In regions with an **impermeable surface**, water **cannot infiltrate** the ground, leading to **increased surface runoff** and the formation of **more drainage channels**, resulting in **high drainage density**.
• (D) Permeable surface layer: Incorrect. A **permeable surface** allows water to **infiltrate**, reducing **surface runoff** and consequently **lowering drainage density**.

Step 2: Selecting the Correct Answers

Based on the above analysis, the correct factors that contribute to **high drainage density** are:

\[ \mathbf{(A)\ and\ (C)} \]

Final Answer:

Thus, the correct options are: (A) and (C).