The selection and placement of stone needs to be carefully contemplated and executed in order to achieve a natural, stable and aesthetically pleasing finish
Stone size needs to be in scale with both the pond and yard size. It is also key to support the stone with a concrete collar to avoid tipping and collapse at a later date |
It is a good idea to see a variety of stone first hand before you make a selection on the type of rock you want to incorporate. The first consideration is scale. You do not want to place huge 1200 lb. boulders around a small 8 foot pond. Your existing landscape logistics also need to be examined so that the pond blends in in a natural way
As a rough guideline, 1 ton of stone is required for every 10 - 15 feet of pond perimeter. Rock weighs approximately 150 lbs. per cubic foot. This means a stone 2.5 x 2 x 1.5 will require at least 2 strong men and a rock cart to move properly
Again, the best piece of advice I can give is to go to quarry yourself so you can select the stone that appeals to you ! Do not purchase your stone from a Nursery as you will pay a huge premium. Do not rely on someone else to select your stone, they may not have the same taste as you. Take your time, walk the yard and choose the stone that you like best. Bear in mind, stone can change colour somewhat over time due to the sun - it never hurts to ask questions |
in or out of the Water ?
One key consideration in the placement of the rock is will it be in or out of the water?
First and foremost, fish can get injured on submersed stone, particularly during spawning and feeding Obviously, sharper edged stones are of a greater concern
Secondly, there are effects on water chemistry. Many lakes have had there eco systems destroyed due to acid rain here in Ontario. Lakes with limestone bedrock however, do not number among then. Numerous types of natural stone will buffer the water and provide a stable pH of 8.4 - rocks containing Calcite, Dolomite [CO3] are excellent buffers as they bind hydrogen ions that would otherwise form weak carbonic acids [which lower the pH]
Personally I prefer rock placed in the water as it provides a much more natural look. In my experience, fish injuring themselves on stone tends to be the exception and not the rule
If herons are a problem in your area, large perimeter stone will hinder them from walking into your pond and fishing. Large stone 1 or 2 feet above the ponds surface makes fishing difficult for them
|
Hotly debated by opinion rather than science, rock bottomed pond systems are easily debunked when it comes to their supposed superiority. In all the ponds I have worked on, all but a single one have had a thick layer of detritus amongst the rock. In extreme cases, rock is caked together so thoroughly that it requires a crowbar to separate. These dirty conditions become breeding grounds of pathogenic bacteria and as a byproduct release toxic hydrogen sulfide and methane
Of course these systems can function, even for extended periods but they are so far from ideal. The gradient between a fish merely surviving and thriving is vast - saying my fish look great without quantitative data and an educated eye means very little. Fish surviving year after year is often a testament to resiliency of these animals, not the pond's design or keepers skill set
Also of note is that no one uses rock anymore as a filter medium. The reasons are numerous. It is difficult to clean, it channels and most importantly, does not supply a great deal of surface area per cubic foot for nitrifying bacteria. To sustain large numbers of bacteria, water is pumped through a filter to provide oxygen and nitrogen [food]. Rock at the bottom of a pond simply does not provide optimum conditions for nitrifying bacteria to thrive. Lower depths are more prone to becoming anoxic so that key conversion of NH3 [ammonia] to N02- [nitrite], which requires oxygen, is less likely to take place
Other Key Points
I have a rabbit named Token. I don't wait for bacteria to break down the excrement naturally, I clean the litter pan. A pond is no different, it is essentially a cage and hygiene is of great importance. A rock filled "fish pond" is not the same as a sparsely populated stream. In other words, you can't ultimately rely on a natural process occurring in an unnatural setting
|
