( ( ( Water flow ) ( -LRB- ( current -RRB- ) ) ) ( ( is ( ( the ( driving force ) ) ( behind ( such ( sediment transport ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNP Water) (NN flow)) (PRN (-LRB- -LRB-) (NP (JJ current)) (-RRB- -RRB-))) (VP (VBZ is) (NP (NP (DT the) (VBG driving) (NN force)) (PP (IN behind) (NP (JJ such) (NN sediment) (NN transport))))) (. .)))
Water flow (current) is the driving force behind such sediment transport.
(ROOT (S (NP (NNP Sediment)) (VP (VBZ is) (VP (VBN transported) (PP (IN by) (NP (NNS currents))))) (. .)))