Cinematic rage against the machine. Documentarians Carl Deal and Tia Lessin capture the Katrina disaster mostly via home video footage taken by Kimberly Roberts, a resident of New Orleans’ doomed Lower Ninth Ward. Her camera recorded the Biblical floods, the astonishing wreckage, the infuriating governmental indifference and the ensuing bureaucratic nightmare. The highlight of Trouble the Water? When Roberts, an aspiring rapper, unleashes her anger and disillusionment in a pyrotechnic, impromptu performance of spoken-word verse.