I made this bird fountain about 10 years ago and it has been a gathering place for so many different birds, not only to drink from, but also to bathe in. Because of the varying depth, It has likewise been visited by butterflies and many other insects as a watering hole.
The body of the fountain is a granite rock that had a slight hollow on one side which I chiseled deeper and wider that it was originally. This was time consuming work. When the 'basin' was as desired, I drilled a 1/2" hole through the centre using a hammer drill and tungsten carbide bit.
I leave it running until the first this ice appears on it at the beginning of winter and then simply unplug it. I don't drain it for the winter and I leave the pump in the water which, of course freezes solid but doesn't seem to damage the pump. I replaced the pump only once in the 10 years it has been in operation.
The fountain requires topping up almost every day and a good clean-out each month to remove sediment from the reservoir underneath.
This spring, the water level was going down faster that previous years, so I decided to investigate by doing a complete overhaul of the fountain and took photos for others to view who may want to build something similar.
You will see in photo 2, I had buried a stainless steel bucket in the ground with the lip only slightly above the ground level - 1/8" max. This is the fountain reservoir.
Photos 3 & 4 show the type of low volume pump I used.
I discovered the reason for the fast drainage was that a section of the thick rubber mat had separated . It is made from two pieces that were bonded together with 'professional' exterior adhesive. It had held together for 10 years which in my opinion, is remarkable. However, this time I bonded the two pieces with black Premium Waterproof Silicon ll which is claimed to be sun and freeze proof. You will need some of this silicon even if your rubber or plastic barrier is one piece.
With the edges of the rubber mat (which is actually the rubber flooring used in a skating rink) thoroughly cleaned, I put wide masking tape on the top side of one piece of the mat (with half of the tape overhanging the edge) and laid it 'top-side-down' on a flat surface. The tape will prevent the silicon adhesive from bonding with the work-surface.
Photos 1 & 2 -I applied a thick bead of adhesive on both pieces of rubber and pushed them together. Don't squeeze them tightly together, otherwise the bond will not be effective. leave 1/8" gap between them with the adhesive oozing out as in photo 3 & 4.
I then ran a bead of the silicon around the centre hole to form a 'drip-edge'. This stops the water seeping under the mat when the fountain is operational. Photo 5.
I left this to cure overnight before installing over the bucket in the ground.
The next morning, I temporarily checked the 'fit' of the mat over the bucket. Since no adjustments were necessary, I removed the mat and ran a thick bead of silicon around the lip of the bucket (photo 1) and re-fit the rubber mat exactly where it needed to be. (photo 2) Do not move or slide the mat in place or you will weaken the water-tight seal between the mat and the bucket.
I then place several large rocks around the opening to maintain a good seal during the curing process. Leave in place for another day.(photo 3)
The next day,I removed the temporary weight (rocks). I put the pump into the bucket and positioned a piece of fly screen over the opening with the hose through a small hole in the centre of the screen. Rocks were then placed around the opening which will support the actual granite fountain basin. The next step was to half-fill the bucket with water to test that the pump was still working okay.
You can do this part on your own as I did, but you may want someone to help you position the base, particularly if you use heavy granite like mine. With the heavy granite fountain base 'on edge', I ran the hose up through the centre fill hole and carefully lowered the granite base over the support rocks. Turn on the pump and using smaller flat stones, level the base so that the water runs over the edge where you want it to, but leaves a pool of water in the base.
Once you have the reservoir and the flow over the edge as desired, you can place an assortment of large stones and small pebbles around the fountain to make it blend in with the base and surroundings.
Fill the bucket, by slowly adding water into the fountain using a hose or jug. Once filled, the fountain should need topping up every one or two days, dependent upon the number of bird visitors taking a bath.
The piece of black plastic to the top-right of the photo is an LED light that I have to repair.