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

(N/A) River water contains colloidal particles of mud and clay,which carry a negative charge. Sea water contains various electrolytes such as $NaCl$ and $MgCl_2$. When river water meets sea water,the electrolytes present in the sea water neutralize the charge on the colloidal particles of mud and clay. This process is known as coagulation or flocculation. As a result,the mud and clay particles settle down at the river mouth,leading to the formation of a delta.