'Moribund Delta' is a subdivision of which of the following Delta ?

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Correct — C, the Bengal Delta. The Ganga-Brahmaputra delta is so large that Indian geographers describe it in parts, and the standard scheme is a three-fold one: an active or tidal delta in the south-east, where the Sundarbans are still being built out of fresh silt; a mature delta in the middle, around the Hooghly and Kolkata; and a moribund or decaying delta in the north-west, across Nadia and Murshidabad and continuing into Bangladesh. The moribund tract earns its name because the Ganga's main discharge has migrated steadily eastward into the Padma, starving the old western distributaries — the Bhagirathi, Jalangi, Mathabhanga, Bhairab and Ichhamati. Cut off from a strong flow, they silted up into sluggish spill channels, ox-bows and marshes, and stopped building new land. No other Indian delta is subdivided this way, so 'moribund delta' is a term that belongs specifically to Bengal.

Why the other options are wrong — (a) The Krishna and Godavari build a joint deltaic plain on the Andhra coast that is famous as a rice bowl and as the KG hydrocarbon basin. It is an active, wave-and-tide-influenced delta, and Indian geography does not divide it into moribund, mature and active tracts.  (b) The Mahanadi delta around Cuttack and Kendrapara in Odisha is a comparatively compact arcuate delta, known for the Bhitarkanika mangroves and for flood problems, not for a decaying sub-division. The moribund terminology is never applied to it.  (d) The Cauvery delta of Thanjavur, the granary of the south, is one of the oldest engineered deltas in the world — its distributaries have been controlled since the Grand Anicut was built across the river. It is described as an old and heavily irrigated delta, but not through the moribund-mature-active classification of Bengal.

Concept: A delta is not a single, uniformly growing landform. Where a distributary still carries plenty of sediment, the delta front advances into the sea and the tract is called active; where the river's flow has moved elsewhere, the abandoned lobe stops growing, its channels silt up and it becomes moribund — geologically alive but hydrologically dying. The Ganga-Brahmaputra-Meghna delta, the largest in the world, shows both states at once because the Ganga has been shifting its main course eastward for centuries. The precise names and boundaries of the sub-divisions vary a little between authors, but 'moribund delta' consistently refers to the decaying north-western tract of the Bengal delta.

State PCS 2019 Q50 — Geography PYQ with Answer

State PCS 2019 Q50 — Geography PYQ with Answer