NEW : Judge Stanwood Duval believes Congress deserves blame for role in the flooding . Duval rules 1928 law shields the federal government from liability over flood controls . Congress ' plans appeal , Thursday press conference .
NEW : Judge Stanwood Duval says Corps deserves blame for role in the flooding . Duval rules 1928 law shields the federal government from liability over flood controls . Plaintiffs attorney plans appeal , Thursday news conference .