Global Flood: I Survive on Duckweed

At first, everyone thought it was a welcome rain, but unexpectedly, it rained for a full ten months! All the land was submerged, and the entire Blue Star became a pure water planet! Cruelly pushed off a small boat, Ren Yuanyang awakened the Enhancement System on the brink of death, and started enhancing from a single patch of duckweed! Just as Ren Yuanyang established a firm foothold, new disasters followed one after another... — Description from novelcodex.org