Initially, I purchased a fibreglass, ready-formed stream, complete with pump. It was OK as a temporary measure but when I realised I would need to bed it into the landscape, I recognised its limitations. It was also very expensive and very short.
I then consulted various books and websites. I had originally intended to construct the bed of the stream entirely from concrete, but the books suggested this was not advisable as it cracks easily and ceases to be watertight. Ready-made sections or waterfall and stream seemed horrendously expensive - I worked out that even a short two metre stream would cost over 600 GBP. Using PVC or rubberised pond-liner seemed a better option, but would be difficult to blend into the landscape. Eventually, I opted for the method described below which aims to combine the reliability (and cost effectiveness) of a flexible liner with the creative potential of concrete. I have had one section in place for over a year now and it seems to be weathering nicely. The photos for this update show an extension I have added to the original stream.
Stage 1I planned where the stream will flow - making sure there was a gentle fall from top to bottom.
At the bottom of this photo, you can just see the top of the original stream. Also, you can see the junction-piece ready for extending the pipework.
Stage 2I dug out the bed for the stream with a trowel, digging approximately 6 inches (15cm) deeper than the actual stream bed.
You can see I also chiselled into to blocks supporting the trackbed as I needed more width for the stream at this point.
Stage 3The pipework is laid at the bottom of the trench. You may prefer to lay this to one side, in case leaks need to be repaired. I'm working on the principle that plastic pipes are almost indestructible and are more likely to be damaged by careless digging - hence laying them beneath the stream itself where there will be no digging.
The rocks are there to hold it down for the photo and were removed during the next stage.
Stage 4Soft sand was laid over the pipe, to provide a bed for the stream. Where possible, it was moulded up the sides of the stream to ensure sharp stones don't puncture the liner.
Stage 5I used some foam packaging which was wrapped around some electrical good to act as an additional cushion for the liner. This is not essential but I had it to hand and hate to see waste.......
Stage 6I next laid the liner which as you can see is initially much wider than it needs to be - easier to cut of excess than try to extend something which is too narrow.
Now came the creative part. I carefully selected chunks of sandstone to line the sides of the stream. Because the stream was very narrow, I had to cleave some of the blocks. I suppose you could use pebbles, stones or gravel but as I had some chunks left over from building the rockery I used these - and it ties in with the locality.
Once I was happy with the position of the rocks (and this took more than a little trial and improvement), I trimmed back the excess plastic liner and the foam 'underlay'.
I then tested the stream by turning on the pump. When making the original stream, I had to test it by pouring water from a bucket as the pump I had then was too weedy. I quickly realised the flow was going to be too great for this new narrower stream and so decided to split the pipe at the point I had joined the new length to the old. I now have an outlet flowing into the original stream and an outlet flowing into the new stream.
The messy bit! I donned a pair of rubber gloves for this - I prefer the 'hands-on' method. A mix of 5 parts sand to 1 part cement was slapped, slopped and splodged behind, under and between the rocks to fill the cracks, provide a bed for the stream and, in places, create some new rocky outcrops. If I hadn't had any rocks, I could probably have moulded my own from concrete. I use an old 2" household paintbrush to smooth down the cement - it can also provided in interesting finish if it is stippled on the surface. When concrete is 'green' (ie when it has partially dried out but before it is hard) it can be sculpted and scribed.
I tend to then leave it for at least a week to harden. If the heatwave had continued, I would have covered the concrete with damp cloths to prevent it from drying out too quickly. Similarly, if it rained heavily I would have covered it with polythene.
ConclusionI have no idea how durable this approach will be - a hard winter might result in some frost damage. However, I anticipate it will be relatively easy to repair any cracked concrete and the liner should prevent leakage (should!).
Views of the stream
The new extension
Where the new joins the old
The original stream
Update - July 2012
Over the past six years, the stream has become blended into the landscape. Moss and Mind Your Own Business (aka Baby's Tears) now line the banks and dip into the flow, giving the stream a more natural look.
From time to time I have to clear out the waterways of encroaching undergrowth - but this takes only a few minutes a couple of times a year. There is some seepage of water, which means that if I run it for around half a day I have to top it up with around a gallon of water. I can't figure out where the water is escaping as nowhere seems to become soggy, but this rate of seepage is something I can live with.
I am now considering adding a mill beside the main stream. It will be positioned on the further bank and will require its own dedicated siding - similar to that found on the Southwold Railway. As it will be on the furthermost bank of the stream I will need to build a bridge - and a simple timber trestle seems the most appropriate (again similar to that on the Southwold. I am also interested in building a fairly realistic mill race and sluiced leat to feed the mill. I'd like to be able to regulate the water flow in some way so the wheel doesn't end up spinning madly (and unrealistically) - but that may prove more difficult than I imagine!