Things have been moving forward slowly over the last few weeks. The first house is basically done, and we are now working on the balcony rails and mosquito screens. For the pond, it has been slow going washing gravel in 2 cement mixers and laying it down. Unfortunately, the cost of trucking in washed gravel was significantly more than the cost of buying a few cement mixers plus the cost of labor to wash the gravel one load at a time.
So here is a picture of washed sand around the “shallow zone” of the swimming area:
Note that the deeper area has already filled up with rain water (it has about 1.5 meters deep water now). Eventually the water will fill up another 1.3 meters so that a potential swimmer can stand on the washed sand and be waist deep in the water. In the distance you can see the wall for the smaller regeneration zone. The final water level will be about 10cm higher than the top of that brick wall.
Here is another picture where you can see the large 12″ PVC pipes that run from the larger regeneration zone to the cement cisterns where the circulation pumps will be installed:
There are small 6mm-10mm holes drilled in the bottom of the 12″ pipes in the regeneration zone. On the lower left side you can also see a smaller 4″ PVC pipe coming from the regeneration zone to a much smaller garden pond area where we will have a gazebo on the edge of the water. For circulating the water in this smaller area, I am looking to try a “bubble pump” design where the aeration pump pumps air into the PVC pipe and the bubbles moving upwards simultaneously aerate and provide circulation pressure to suck the water out of the pipe.
You can also see that the gravel is now up to the top of the PVC covering the right half of the area of this regeneration zone. Once the gravel is laid down on the left side, we will put sand on top for another 60cm or so. I don’t think this will be done for at least another month. Then the regeneration zone will be done (waiting for the water level to rise high enough to plant it).
In principal, I am expecting the water to seep down slowly through the sand and filter out any contaminants (as mentioned in a previous post, the idea being to build up a biological filter level on the top as in “slow sand filtration“). Once the water gets down through the sand layer to the gravel layer, it will hopefully be able to flow more freely toward the holes in the PVC pipes where it will be sucked in and circulated back to the areas of the pond farthest from the regeneration zones.
More progress updates to come…