subdeltaic
/ˌsʌbˈdɛltɪk/ or /ˌsʌbdɛlˈteɪɪk/Definitions
1. adjective
Relating to or characteristic of a subdelta, which is a landform formed by the deposition of sediment from a river.
“The subdeltaic landscape in the Mississippi River delta is a result of thousands of years of sedimentation.”