海水倒灌

saltwater intrusion

surname Hai

ocean / sea / CL:個|个[ge4],片[pian4] / great number of people or things / (dialect) numerous

seawater

surname Shui

water / river / liquid / beverage / additional charges or income / (of clothes) classifier for number of washes

to fall; to collapse; to lie horizontally / to fail; to go bankrupt / to overthrow / to change (trains or buses) / to move around / to resell at a profit

to invert; to place upside down or frontside back / to pour out / to tip out; to dump / inverted; upside down; reversed / to go backward / contrary to what one might expect; but; yet

to flow backwards (of water, because of flood, tide, wind etc) / reverse flow / to back up (sewage)

to irrigate / to pour / to install (software) / to record (music)