Sediment.
alluvial fan
true
Vein and/or Peat (depending on reference, peat is the beginning form of coal).
tributary
Alluvial Fan
dirt
colorado river
Ponni , the other name of cauvery river.
This deposit is called a "delta".
Tributary when one river flows into another or if more than one river merges to form another - Confluence
a place where a river meets the shore
St. John's River