Re-Building the Bog on the New Pond


The finished bog viewed from the pond side.

The last pond that I built in 2010 I call the New Pond. It is over 6000 gallons and the largest one that I have. The first pond, built in 1990, is now relegated to the name of First Pond as it falls behind in size containing just 5000 gallons.

When I built the New Pond, I included a small bog on the side that was fed by it’s own supply from the main pump. It then returned the water back into the pond by gravity feed. I was pushed for room when I built it and it measured about 2 ft wide and 8 ft long with stacked stone walls on the three sides away from the main wall of the New Pond. I used the standard construction method which comprised of a liner and then filled with loose pea gravel. I planted it out with a mix of different plants and for the longest time, it worked well.

A couple of years ago, I noticed that the water level was dropping in the New Pond and went through the usual methods of trying to isolate where the leak could be. First, I shut off the pumps and the water still went down which told me that the leak was either in the pond or in the bog (or both). Suspecting that I had a rat chewing problem, I started a serious search from within the pond all the way around the water level and discovered an area of about 6 feet that the rats had chewed through the liner in several places from within the surrounding rocks which they had made their home. This resulted in me having to drain more water out of the pond to lower the water level and then to apply several glued on patches to the affected areas. The repair was simple enough and after giving it time to cure, I refilled the pond and started everything back up.
The water level held up for more than a year and then started to drop again. Suspecting more rats, I checked the repairs and they were still holding up so by a process of elimination, I isolated the bog area which turned out to be the culprit. With a lot of other things going on like Septic Tank Repairs, remodeling the bath to a shower and a host of other things, I just turned the bog off and let it grow out which it did with the most amazing display of Green Taro.

Having caught up with many of the other pressing things in my busy life, I turned my attention to this bog. Reluctantly, because of the Taro’s amazing growth, I dug out all of the plants, some in pots and others having already outgrown them with roots going everywhere. I saved the rhizomes for future use, transplanted what plants I could and then proceeded to dig out the gravel. I forgot to mention, that for once, the position of this bog with the gravel path running alongside of it, made it very easy to work on. As I removed the rocks that made up the exterior walls, I re-laid them into the new wall with very little effort so that I had the outline of the new bog. I was able to increase the size to about 3 ft average width and 12 feet long. I also planned to tear out the waterfall I had previously built and use the outlet from the bog to act as a return waterfall.

I dug out all of the dirt inside the new walled in area and cleaned everything up. I then completed most of the stonework bringing in other stone from a pile that I had elsewhere until the shape and depth were sufficient.

I was then faced with the problem of what to do inside the walls as in their current state, I could not cover them with a liner as the stones were so uneven. I got over the problem by building a 2 x 4 form which I filled with concrete. I used old wire mesh and used hardware cloth that I had laying around from another project for reinforcement to help hold it all together. When I finished the long wall, I worked alternately on each end wall so that the finished product was completely lined with concrete on the three sides. The side that surrounded the pond had enough existing dirt still from the original excavation that all I had to do was fill a few holes with concrete and smooth them over.

I measured the hole for the liner several times to make sure that I was allowing enough. As you pay for the liner by the square foot, it is very easy to want to skimp on it. I erred in the other direction having already made the mistake of having the liner a few inches too short on previous projects and having to make adjustments because of it. I visited Jeff Yarborough at Leaf Landscape Supply to buy the liner as it is only a couple of miles from my house. Jeff is one of our Speakers and the company is one of the Austin Pond Society Sponsors so I like to give them my business. Not only that, I get a Club Discount which also made it worth while. As I usually do for this sort of thing, I drove out the back and helped one of the workers lay out the liner and then fold up the piece and put it in my trailer.

I needed some used carpet to put under the liner to give it a cushion and protect it from any sharp edges and made a couple of calls. Leaf Supply came through and suggested that I contact a Carpet installer off William Canon which I proceeded to do. They have this huge pile of used carpet outside and for a very small fee (they called it a donation for which I gave them $5), I could take all that I wanted. I got it home and installed it to completely cover the inside of the excavation.

On my previous efforts of handling large pieces of liner by myself, I had already figured out the best way to do it is to lay it out and then re-fold it in the way you want it to unfold. This save a lot of pulling and dragging and risking moving the rock walls or damaging the liner. It is much easier to move a liner in small lifts than to try to drag the entire thing. I’ll bet the piece that I had probably weighed a 100 pounds.

With the liner in place and folded the way I wanted it on the corners, the next step was to work on building the water chamber. This comprises of a space of about 8 inches between the floor and the medium that was going to hold up the larva rock which I was going to use as filter material. There are a variety of ways to create the space. Several of the Pond Society Members have acquired plastic Coke crates and stacked them end to end to fill up the space. I didn’t have a supply of these items but I did have an 8 x 4 feet sheet of small lattice plastic fencing material and several 8 x 16 concrete blocks. Prior to placing the blocks, I cut small pieces of liner to fit under each one so as to shield the liner and help to protect it. I placed enough of the blocks in such a way to support the lattice without any fear of it collapsing under the weight of the larva rock and then cut the lattice to shape. I used the entire sheet and prior to installing the lattice, I installed two 2 inch PVC pipes through which I had pre-drilled two rows of 1/2 inch holes about 6 inches apart. I threaded these pipes through the blocks so as to raise them off the bottom. I covered the whole thing with a layer of weed cloth of the absorbent kind that would allow the water to go through.

Having successfully gotten this far, I then filled the bottom up with water to allow the liner to settle into the corners before completing the rest of the work. The next part of the project was to hook up the plumbing which was a fairly easy job as the service to bring in the water from the pump was already in place. Using a tip learned from my previous work on the plumbing for the Septic System, I drilled a 1/4 inch hole below the water level in the upright feed pipe inside the bog to prevent an air lock as the pipes went from the ground, up and over the wall in the shape of an inverted U and back into the bog.

The next order of business was to purchase the larva rock. Previous experience had shown me that the bags at Lowe’s are 1 cubic foot compared to those at Home Depot which are only 1/2 a cubic foot for almost the same price. I purchased 14 of the bags. I was going to just put the rock into the bog loose but again, my friends warned me that it is tough to dig it out when the time comes to clean the bog and that I should use bags. With much more forethought and skillful planning than me, they had managed to buy used craw-fish bags from Louisiana at a fairly cheap price. I had to make do with laundry bags from Target which I paid a bit more for but mine are a little bigger and can contain more rock. Of course, that may also be a disadvantage as they may be too bloody heavy for me to get them out when the time comes. Given a few more years, and I doubt if I can lift what I do now. It’s hell growing old for many reasons.

I filled the bags and carefully installed them in the bog and filled in between with loose lava rock. The original plan was not to plant any pots or marginal plants in there but it looked so bare that I relented and stuck back in many of the same plants I had dug out of the previous bog. That was after re-potting them.

Before filling the bog with water, I checked to see that the outlet rock, a 2 x 1-1/2 foot slab was positioned and was level. It was very important for getting the proper waterfall effect, that this particular item be almost perfect. This rock, I had bedded in a mortar mix in order for it to be correct. I had already stacked rocks on the inside wall and used spray foam to fill the joints and prevent the water spilling out in the wrong places. I turned my attention back to the outside walls and completed placing the rocks to give it a finished look.

Then came the moment of truth.  I filled the water back into the bog and added
de-chlorinator to prevent the new water from affecting the fish in the pond. As the water rose, I adjusted the liner in a couple of places and then watched as it reached the outlet stone and came out in a perfect waterfall. Breathing a huge sigh of relief, I watched for a while and then gave myself a mental pat on the back for another completed project.

It took me almost 2 weeks to complete this job and that was with long hours. Sometimes, I would run short of this or that and have to make a quick run to Lowe’s or Home Depot. Luckily, the weather for most of the time was pretty nice although it did get hot (for the time of year) for a couple of days.

The next projects are already in the works. This time, I have to explore why both streams are leaking. I have already re-built the Little Old Man stream 3 times with the last time of adding a concrete bottom and sides under the liner. As you have probably guessed, I have a rat problem in both of these areas too. For now though, as it raining fairly heavily outside, I am content to just write about the stuff already completed. Oh yeah, a big thank you to all of my friends for their words of wisdom. They helped me to stop from copying their mistakes.