Regeneration zone

Up to this point, I have been presenting things in chronological order.  Now that various bits and pieces are being worked on simultaneously, it'll be easier if I just talk about one aspect at a time.  Let's start with the all important regeneration zone.

The regeneration zone surrounds the swim area and will handle the bulk of the water filtration.  This occurs as pond water is drawn through a layer of gravel, which eventually will be planted with a number of aquatic plants.  The gravel traps things in the water that don't float (like soil) filtering them out of the water.  It also provides a home for beneficial bacteria that will consume much of the nutrients in the water so that algae will not have as much to live on.  The aquatic plants will also take up nutrients and provide some shade, further depriving algae of nutrients and sunlight.  That's the theory, anyways.

The first step was to finish lining the pond by splicing the extra 10' width of liner.   Aquascape makes EPDM splicing tapes -- a 3" double-sided tape that adheres the two sections of liner together, and a 6" single-sided tape to cover the resulting seam.  The tape is made of the same material as the liner.  Although the instructions tell you to work on a flat, clean surface, that wasn't possible here.  Working slowly over our lumpy, creased liner, it took two of us about 2 hours to join the two liners, and then it took me another two hours to apply the 6" cover tape.  Note that the instructions "recommend" using a primer (also available from Aquascape) on the portions of the liner to be spliced/taped.  I would say the primer is mandatory for a good seam.  It makes the liner tacky and bonds the tape so well that it is impossible to pull apart.

Next, we put a layer of filter fabric over the liner in the regeneration zone to protect it from the 60 tons of gravel that will be dumped on it.  As you can see, our last load of water was enough to put several inches of water in the regeneration zone, which helps press the liner into the outside of the deep zone walls.

Finally, it was time to do some plumbing.  In order to draw all that water through the gravel, three 50' lengths of 4" drain tile were placed in the regeneration zone.  I used a variety of fittings to connect the drain tile to three lengths of 2" flexible PVC pipe, which will eventually be connected to the suction side of the pond pump.  The drain tile floats, so some rocks were placed on it to weigh it down.

Time for the gravel.  The bottom layer is 2" to 4" natural cobble, meaning that it is a smooth river rock as opposed to the jagged crushed rock.  Brian skillfully dumped gravel into the regeneration zone with his loader as I sat on the deep zone walls simultaneously holding the drain tile down with my feet and pulling up on the filter fabric so that it didn't get pulled away from the liner.  After each two or three loads, we would push the rock by hand into an even layer.  It was fairly exhausting work, but went pretty quickly.