silt up
C1 neutral inseparable both
In simple words
When mud and sand slowly fill up a river, harbor, or channel so that water can't flow properly.
Literal meaning: Silt (fine sand and mud) moves upward to fill a space — the process of sediment accumulation.
Meanings
1 C1 neutral
Of a waterway, harbor, or channel: to become blocked or filled with deposited silt and sediment over time.
"The old harbor has completely silted up and can no longer receive large vessels."
Grammar: inseparable
2 C1 neutral
To cause a waterway to become blocked with silt.
"Years of agricultural runoff have silted up the river delta."
Grammar: separable
Usage notes
Primarily used in geographical, environmental, and engineering contexts. Often refers to rivers, harbors, canals, and reservoirs. Can be used transitively ('Silt has silted up the harbor') or intransitively ('The river silted up'). More common in British English.
Commonly used with
harbor river canal reservoir estuary channel
Forms
Base
silt up
I/you/we/they
3rd person
silts up
he/she/it
Past simple
silted up
yesterday
Past participle
silted up
have + pp
-ing form
silting up
continuous
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