The water garden project is moving along nicely. I have purchased the barrels, pump, tubing, and the bricks to elevate the upper barrel.

The most difficult aspect of the project thus far has been getting the wooden barrels to hold water. The barrels were very dry when I purchased them. So dry in fact that they were nearly falling apart. In order to get them to hold water again I had to get the wood to absorb water so that it would expand and seal up. I accelerated this process by hanging wet towels over the sides of the barrels and pouring water over them several times a day for over a week.
The process is slow but it negates the need for a liner and, in my opinion, makes the water garden look better. It is also necessary for this project because I plan on putting three holes in the upper barrel to spill into the lower barrel which would be much more difficult (if not impossible) to achieve with a liner in place.

Soaking and filling the barrels as well as watering plants on my patio is interesting in itself as I have no faucet outside and must fill empty milk jugs with water and haul them through the apartment. (Please excuse the mess in the sink.)
I have had the most trouble sealing the top three to four inches of the barrels agains leaks so I choose to seal the cracks with silicone caulk. The silicone should maintain a seal and allow for the spaces to expand and contract with varying moisture levels and different temperatures.
After allowing the silicone to thoroughly dry I moved the barrels back outside and drilled the holes, filled them with water, and installed the pump. I inserted plastic tubing in to the holes to help project the water farther away from the side of the barrel.
Up next: Putting plants in the water garden...