There are rigid liners -- which have shapes already built in -- and flexible ones. Within each category there are many choices and the Water Gardens book I mentioned previously does a good job comparing the options. For me, a flexible liner was a given as this is a custom shape (the pond may look circular from a distance, but it intentionally has a slightly irregular shape to make it look more natural). And I was ready to invest in the best quality as I wanted a liner that will last as long as possible -- 30+ years ideally.
This meant a rubber liner with underlayment fabric to prevent possible tears from rocks or roots underneath. You won't get this material at the big box home improvement stores in my area, and the pond specialty stores provide it at a steep price. I found it for a decent price at a local rock/sand yard. This next photo shows Emma and Daniel posing after the underlayment was in place (they helped with that project):
The rubber liner was one of those projects where you have to do it first before you really know what to do. It sounds simple enough in concept. But the books talk about knowing where to fold over the liner and about splicing two pieces together. The splices are especially tricky because even with the recommended splicing tape there is a big risk of leaks. Jack also talks about using rubber material where the manufacturer adviced against cutting it. That wasn't the case with the material I had, but that was something I had to figure out on my own.
We started at the pond and worked our way upstream with the rubber. One mistake I made was to undersize the rubber liner piece for the pond, necessitating a splice under the pond itself (which I'd hoped to avoid -- intending instead to have splices only under the moving stream water). I was trying to save money when I bought the rubber liner sections so stuck to the narrowest pieces available -- 10' -- in retrospect it would have been better to buy the 15' sections and accept that there was going to be some wastage.
We spliced the liner in place. If I was to do it again I'd choose a level surface, then move the liner over to the water feature. I bought mineral spirits, as recommended in the instructions, for cleaning the liner surface and applied the splicing tape as described. It worked, except where the irregularities of the ground surface caused the liner to bend up, and in those cases it appeared that the splices had gaps (this is why I would have used the level surface first). After trying a number of things I filled the apparent gaps with caulk ("Polyseamseal") and relied on the weight of the covering material to keep the whole splice closed. I know know that this works -- our water feature has been confirmed not to leak -- at least the pond itself. But at the time we were simply operating on faith.
With the liner in place the next step was to add the surface material. Jack Verducci, as noted in the previous post, recommended a mixture made up primarily of ready-mix mortar, plus doses of portland cement, fire clay, and dehydrated lime. He said the resulting material was easy to work with, allowed you to shape the pond surface, and allowed you to fix pond and stream rocks in place. He also noted that you could choose the color of the mixture with cement dye.
My first problem was finding the materials. Mortar and portland cement are available at any big box home improvement store. Dehydrated lime was hard to find, but I did eventually locate a single old bag of it at a local garden store. I never found fire clay as a product, although it's all over my geological maps of the Rockies. Maybe this is a product that garden stores have in Jack's area, northern California.
The next issue was that with all my home improvement stuff over the years I'd managed to avoid any cement or mortar work except fence post concrete. I thought about renting a cement mixer, but was told that I really needed a mortar mixer, and those are hard to find. (I later learned that mortar is much thinker and harder to mix than cement, hence the need for a special item.) However, I was told you can buy a hard plastic mixing trough for about $11 and mix with a hoe, which is what I did.
Now, the Water Gardens book mentioned use of cement or mortar as a possible filling for a garden pond, but more as an aside not as a recommended practice. They also suggested pouring the mixture over chicken wire, placed over the liner, to add strength. I didn't do this as I was following Jack's method, however now that I've seen the results I might try that suggestion for my next water feature.
So, I started at the bottom of the pond, figuring that any mistakes made in appearance could be more easily corrected there even after the rest was done. This is one of those "contingency steps" I talked about in the last post. My first batch was only mortar with portland cement, using a "charcoal" colored cement dye. This seemed to go okay. I'd bought a variety of mortar shaping tools and quickly learned which ones I liked the best. After it dried I found that the dark color of the mixture turned very light, making me wonder what use the dye was. I learned that if the mixture was put on too thin it would tend to easily crumble under weight, so 1" thick was the minimum I used after that.
I added lime to the next batch and it made the whole thing crumbly and barely useable. I haven't reused lime since. Probably the lack of fire clay means that lime isn't an option. The next two batches were just with portland cement added to mortar, and I tried different things with dye, but it still usually dried very light. Then I found, during a rain storm, that when wet the mixture returned to the died color. Interesting.
Next I tried a batch of mortar only, no portland cement, and this seemed the easiest to work with so I stuck with that method moving forward. As I got near the stream bed I changed dye color, to try to match the natural area I was trying to model. This was a mix of "Buff" and Terra Cotta", which resulted in a reddish brown. I also added a bit of sand to the surface while the mortar was dry and a few stones to see how they held up. This picture, taken on August 9, shows the mortar work to that point. It also shows the rubber liner in place, and the splice seams are evident:
I have to admit that up until the stream I was really doubting the whole method that I was employing. However, the stream started working out. I figured I plow on upstream, and would address the pond bed later if needed. As it turned out, the pond bed came out just fine, but that's a later topic.
Moving to the stream bed meant moving to modeling, artistic phase. I spent some time looking at on line photos of the Arkansas River in the Salida area, noting features like islands, river depth, rocks, and river sides. At this point some of our kids got involved because of the fun of modeling, notably Paige and Emma, and this photo shows them hard at work the next day:
The next day I looked at the results of our efforts after the mortar had dried. It actually looked, to my eye, pretty good. This photo shows it from above, but doesn't really do it justice:
You see the island, and if you look closely on the sides you can see a few rock-lined gullies that the kids put in -- just like on the real river where streams come down the river side. There is also an attempt to use rocks to create a natural mini-waterfall like appears in places in the Arkansas River. On this last feature, I had found a sprinkler pipe when I dug the stream bed, and I left it in "just in case" we ever wanted to use the sprinkler system again. I chose to put the liner over it and use it for this water feature.
As I looked at this I realized I had little idea how it would all look when the water was running. I toyed with the idea of running water temporarily to find out, but decided not to as I figured I could correct any problems later with more mortar or by adding loose stones and sand. It turned out that this was exactly what I would do.
By August 15 I'd gone back to the pond area and put in the walls, using the methods that I'd settled on in the stream beds, with mortar, cement dye, and putting sand on top of the mixture after the whole thing had been smoothed out. You can still see some seams in the wall between different batches of mortar -- I was getting better and hiding them but still not perfect. For the record, the walls in this photo took about 15 60-pound bags of mortar -- and another 6 or so for the thinner floor (the walls were up to 2" thick in order to provide sufficient support):
Fast forward 5 days to August 20 and the stream bed is nearly done, in this photo taken from the top of the wall that will be the source of the waterfall:
As I moved upstream the walls got higher and steeper -- a natural result of the fact that I dug the stream bed deeper upstream, and lower downstream nearer the pond. I decided this would be more like canyon walls, and that I'd first build the stream bed then come back and build the canyon walls. As I moved upstream I thought of how real rivers appear near waterfalls, and remembered that there are often large rocks at the bottom of the waterfall itself -- rocks that fall as the water erodes the waterfall wall -- then there is evidence of those rocks downstream as the move slowly, usually in floods over millenia, and get slowly smoothed out. I tried to recreate that with the rocks I used, and also increased the number of small rocks in the streambed, using rocks from backs of concrete gravel which, by luck, had the right color.
I also began collecting rocks to serve as the canyon wall. I made a couple of trips to the local rock/sand yard and found some bulk stones that fit the bill, and were very cheap because of their irregular shapes. I also found some similar rocks at a public resevoir near Leadville, on a trip we made at this time, and took those. By the next day the stream bed was complete:
The next step was getting water running. Garden Railways has run a few articles on filtering pond water, and Jack Verducci specifically mentioned a product by Aquascape that is a biofilter that sits at the top of your waterfall. The advantage of the Aquascape system is that it works. The main disadvantage is that it is very pricey, and sold only at pond specialty outlets. There is another minor disadvantage that the instructions are harder to read than they need to be, but if you get stuck the experts at the pond store can help you out.
I looked up Aquascape on line and found that a) no one discounts their stuff, but b) there is a nice store right in our little town that carries it. I went there, plunked down $299+tax, and had the waterfall biofilter box which I installed at the top of the falls (more details on that in a later post). I then got some cheap piping and connectors at Lowe's, and also got a cheap-ish pond pump there. Set it up and on August 21st we started the water running. First the garden hose was used to test the stream and start filling the pond. Then when the pond level was high enough, I started the pump. This shows the waterfall shortly after it was first started, with daughter Laura and dog Sunny looking on (this was a whole family event, pets included):
The waterfall in the photo is actually just a piece of rubber liner extending over the existing rock wall. I intend to replace that with a wall of rocks that match the color of those in the stream bed, but that's probably a project for next spring. My intent was to get the water running.
Well, it was a success. The stream looked great, and everyone loved having the water feature sounds and smells. Over the next few weeks we learned a lot about the whole water feature and made numerous adjustments as a result, which I'll cover in my next post. Simultaneously, I started work on the footbridge over the water feature, which I'll also write more about.
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