( ( A delta ) ( ( is ( ( a ( ( ( subaerial or ) subaqueous ) deposit ) ) ( formed ( where ( ( ( rivers or ) ( streams deposit ) ) ( sediment ( into ( a ( water body ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (NN delta)) (VP (VBZ is) (NP (NP (DT a) (ADJP (JJ subaerial) (CC or) (JJ subaqueous)) (NN deposit)) (VP (VBN formed) (SBAR (WHADVP (WRB where)) (S (NP (NP (NNS rivers)) (CC or) (NP (JJ streams) (NN deposit))) (VP (VBP sediment) (PP (IN into) (NP (DT a) (NN water) (NN body))))))))) (. .)))
A delta is a subaerial or subaqueous deposit formed where rivers or streams deposit sediment into a water body.
(ROOT (S (NP (NNP Delta)) (VP (VBZ is) (NP (NP (DT a) (NN triangular) (NN feature)) (SBAR (WHNP (WDT that)) (S (VP (VBZ is) (VP (VBN formed) (SBAR (WHADVP (WRB when)) (S (NP (DT a) (NN river)) (VP (VBZ empties) (PP (IN into) (NP (NP (DT a) (JJ large) (NN body)) (PP (IN of) (NP (RB still) (NN water)))))))))))))) (. .)))