The Day the River Stopped

Asked to help with packing sand into burlap bags to stop flood waters from damaging houses, three high school friends rush to a neighborhood near the school. What they experience is the unifying efforts of other students and local residents to save each other's houses from destruction. But the River Queen showed up, and she's not pleased with the city's building a subdivision on her land. There is something that can appease her wrath if only the audience knew what it was.