The plan is to assemble the DWC frame built earlier, then lay out tarpaulin as base layer followed by pond liner.
First DWC unit. The frames are assembled using metal corner bracket. Hole for water return to sump tank was drilled prior to this.
Second unit, about 1 feet apart from the first one.
The space between these units became narrower when all 3 are completed. Here I measure and cut the 2-inch UPVC pipe for dry-fitting, before putting on the tarpaulin.
The next day, laying out tarpaulin on the unit. The tarps are secured to the unit by using thumbtacks.
Second unit in progress, I had to work quickly since rain is coming.
Done laying out all three units, seems I don’t have enough time to lay out the pond liner, so I just connect the pipe, and wait for the rain to come down. From my observation, around one hour of heavy rain, the unit only filled about 1 inch deep.
Later that night, I put the styrofoam board in. It’s important to evenly lay out the tarpaulin, because the board might not fit as shown above. Minor adjustment to the tarp and let the unit filled with more water allow the board to settle floating on the water.