Helpful Hatchery Hints - II:RE-SEALING RACEWAY EXPANSION JOINTS

摘要

The first step is to make sure that the bottom of the concrete raceway and expansion joint cracks are absolutely dry. This is so that the polyurethane sealant will stick effectively. In this instance the problem was rendered more complex in that therewere fish in some of the adjoining raceways, so the water supply had to be maintained. Water from the head-box normally flows into the raceways through paired 4 ft (120 cm) square openings which can be closed with 2"x 6" (5cm x 15cm) tongue and groove dam-boards slotted into 2-inch wide steel channels on the sides and bottom of the entrance to the raceway. Unfortunately these do not make a completely watertight seal, so some additional solution was required.