How does a delta form at the meeting place of sea and river water?

Explanation

River water is muddy and contains charged particles of clay, sand and other materials. When the river water comes in contact with sea water, the electrolytes present in sea water coagulate the suspended colloidal particles which ultimately settle down at the point of contact. The point at which river and sea meet is the site for coagulation. The deposition of coagulated clay results in delta formation.