There is no formation of deltas by rivers of the Western Ghats. Why?

Question

Ghissu Editorial · Accepted Answer

Western Ghats rivers build no deltas because their courses are short and steep, their hard-rock catchments yield little silt, and the narrow, wave-washed submergent western coast leaves no room for deposition. They end instead in estuaries such as the Mandovi and Zuari and in Kerala's backwaters.

**Introduction**

A delta forms only when a river brings more sediment than waves and tides can remove and drops it on a gentle coast. The short rivers that rise in the Western Ghats and run to the Arabian Sea, such as the Sharavati, Netravati and Periyar, meet neither condition.

**Why Western Ghats Rivers Build No Deltas**

1. **Short courses**: The Ghats lie only about 50 to 80 km from the sea in most places, so the rivers have short runs and small catchments that yield little silt.
2. **Steep gradient**: They plunge down the western escarpment, as at Jog Falls on the Sharavati, and carry their load straight into the sea.
3. **Hard rock catchment**: Resistant basalt and gneiss weather slowly, keeping the sediment load low despite heavy rain.
4. **Narrow coastal plain**: The Konkan and Malabar plains leave no broad lowland for distributaries to spread.

**Contrast with East-flowing Rivers and the Result**

SKETCH: comparison | West-flowing vs East-flowing Rivers
a: Western Ghats rivers
b: Godavari, Krishna, Kaveri
- Short, small basins :: Long, large basins
- Steep gradient :: Gentle gradient
- Low silt load :: Heavy silt load
- Narrow coastal plain :: Broad coastal plain
- Estuary mouth :: Delta mouth

1. **Coastal dynamics**: The largely submergent western coast faces strong Arabian Sea waves that remove the little silt arriving; even the long Narmada and Tapi form estuaries in the high-tide Gulf of Khambhat.
2. **Estuaries and backwaters**: The rivers end in estuaries like the Mandovi and Zuari in Goa, and in Kerala they feed lagoons and backwaters such as Vembanad.

**Conclusion**

Short length, steep slopes, hard rock and an energetic coast keep the Western Ghats rivers from building deltas. The west coast trades fertile deltas for estuaries, backwaters and deep natural harbours such as Mormugao.

There is no formation of deltas by rivers of the Western Ghats. Why?

Model answer

Practise this question

Physiography1 question

Ghissu