estuary – n. an area where a river flows into the sea

benefit – v. a good or helpful result or effect

sediment – n. material (such as stones and sand) that is carried into water by water,

muck – n. wet dirt or mud

fragile – adj. easily broken or damaged

zone – n. an area that is different from other areas in a particular way

ecosystem – n. everything that exists in a particular environment

manage – v. to have control of something

source – n. the beginning of a stream or river of water