In this post I will talk a little about the construction of the pond and the feeder stream.
Although a little digging was done in the Fall of 2013 most was done in the Spring of 2014. All digging was done by hand. This was a challenge because of the tree roots and rocks. A few young trees had to be removed too, but most of the clearing of the ground had been done in Fall 2013. A pond liner was to be used so care was taken to remove sharp tree roots and a liner was used as shown below. Digging took a few days of solo effort, with significant time spent to extract roots and stones.
The basic pond shape was an oval, though a large boulder appeared. I realized I was not going to be able to extract it so I decided to work around it and use it to make the pond irregular in shape. As rocks were unearthed they were put to one side for the pond edges. The pond depth was maybe 18 to 24 inches. Not too deep, to maximize the shallows for wildlife. As mentioned in the first part this pond was not intended for fish. The pond had shelves dug in to the sides to vary the depth. Care was made to keep the overall edge level and a spillway was designed into the pond too. As the water collected off the house roof was used to feed the pond (see part 1), a spillway for excess water from significant rain would be needed to control the release of the water, rather than let the pond overflow on all sides. Water from the spill way could be used in some other ways too, but that will be a later project. The pond liner used was a 8 x 12ft black PVC and so the pond dimensions were approximately 5 x 9ft, the difference allowed for the depth of the pond.
Once I had got the excavation to a point I was satisfied with I added two layers of pond underlay before the liner. The first was cardboard (from the shipping of the passive solar panel) and then came the underlay that was supplied with the liner.
Once the liner underlays were in place and smoothed out the liner was inserted. In the foreground of the photograph of the liner you can see the piece of wood that is laid over the feeder stream entry point.
Once the liner was in place washed sand was placed into the bottom of the pond, followed by some washed gravel. Washing removed much of the very fine particles allowing the water to be cleaner when it was filled.
The stream that allows the downspout water to enter the pond was installed and this was just a liner as there would be very little weight of water. The soil the stream liner was laid on was quite sandy so it was just cleaned of any sharp objects and then washed gravel was placed into the liner to give a more natural look. Larger stones were used at the edges to weight the liner down. The liner was a single large piece, but because the stream is long and narrow it was cut into two strips of the right size. Two pieces were overlaid so that the water flowed off one piece into the other piece (which was underneath the upper piece). In the photograph you can see rainwater was already flowing down the stream.
It was early Spring when the pond was dug and the weather was wet, so as soon as the stream liner was added the rain caused the pond to start to fill. In the photograph below you can see that even though the sand was washed the water was discoloured. As well, some of the sand on the steeper parts of the pond edges and base broke away from the liner falling into the bottom.
Construction continued and gravel was added towards the edges and some rocks were added to the edges. Because of the ‘immovable’ boulder the edge of the was nicely irregular.
The next morning a some overnight rain the pond was full, showing how the roof catchment was effective. The photograph below shows the pond the next morning after the day of adding the liner.
The other photograph looks up from the pond at the partly finished stream.
Work continued on the pond. Soil and rocks were added around the edges to make it appear more natural. Plants we added and some seeds were sown. An old branch was added for small birds to perch on. In a week the pond looked quite different, the water had cleared and even a few old Fall leaves had been blown into the pond.
A final word should be mentioned about the spillway. Although at the far end of the pond in the final picture in this post it looks like that end of the pond is blocked by rocks, however there is still a clear route for water to go between the rocks as the water level rises. This ensures the water does not overflow all around the pond, instead it is done at one intentional place.
In the next post (part 3) we will look at the way the pond changes over the following months and some the creatures that visited the pond.