Synonyms for Reefy (same or very similar meaning)
WordNet sense 1 (full of submerged reefs or sandbanks or shoals):
shoaly, shelfy, shelvyWordNet sense 2 (lacking physical depth; having little spatial extension downward or inward from an outer surface or backward or outward from a center):
shallowFrom the ODE community, based on WordNetadd/edit