A method and apparatus for constructing machinery flumes couples precast, fabricated sections of flume having a channel lining in a concrete cast. The sections are assembled to seal end to end forming a continuous trough in which assembly work is contained to reduce installer exposure, reduce field installation time and reduce construction costs for flume systems. Preferably, an end of a lining extends beyond the cast sheath for connection with an overlapped portion of an adjacent precast section's lining.