Hi all, new to the forum. This subject is maybe already talked to death but I used a common image from this forum to illustrate my questions and design idea. I would like to create a siphon from a small pond (15' x 15' x 5') into a bog filter. I know that water can't go uphill but if the bog filter is dug down to be below the ponds water level would this work. Does the outlet need to be 4' below the intake? Is a check valve necessary/useful? Will the water fill the bog filter cistern and spill back into the pond or will the siphon quit when the level in the cistern is above the level of the pond? Thanks in advance for any advice. Happy ponding!
Water seeks it's own level. Once the water level in the bog is equal to the water level in the pond the siphon will stop. You cannot get water to go from the bog filter to the pond without a pump unless you somehow drop the water level in the pond lower than the water level in the bog. To use the bog as a filter you will have to use electricity and a pump. You can leave the siphon in the pond to get the water from the pond to the bog,
esshup is correct that your siphon will cease when the water levels equalize.
Do you have AC electricity available at your pond location? The type of small pump required to perform your task is not that expensive. The amount of electricity used is also relatively minimal.
Rod, No electricity near the pond. Trying to find creative solutions. My last thought on this design is this, imagine that the outlet in the bog is a ram pump. The waste water valve would fill the bog and maybe have enough force to reach the overflow?
Esshup, getting the water level in the pond lower than the water level in the bog wouldn’t be hard. Maybe I’m misunderstanding.
What esshup was saying is that gravity will only move water in one direction until the equilibrium is reached. It will not go both ways. So you need an imbalance of pressure in order to move water continuously. This will require some source of power. Options are a pump like Rod mentioned, or compressed air, a paddlewheel, a windmill, or solar, but will require some source of power. Were I doing it, I think I would prefer to have the bog higher than the pond (say 6") and have the water flowing to the top of bog (rather than under it). Something like gravel to root your plants in and beneath the plants within the gravel perforated pipe to carry the water back into the pond. The bog filter will carry some level of flow initially through the perforated pipe and may not overflow the bog (only move through the French drain. If so, as the bog filter becomes more restrictive ... the level in the bog would rise until such point water would flow back into the pond from on top. You would want some fair portion of the flow to be down through the roots and out of the French drain under the plants. If water is overflowing the bog and can be measured (like in a bucket) and you know the incoming rate ... then the difference is the amount flowing through the filter. If the filter flow rate falls below the number you want, you could do a cleaning maintenance on the bog filter to remove buildup.
Its such a small pond ... is this in your back yard? Is it for KOI, wading, or for amphibians? Would it have to run all the time? or possibly only periodically to clarify the water?
Last edited by jpsdad; 10/10/2306:40 PM.
It isn't what we don't know that gives us trouble, it's what we know that ain't so - Will Rogers
If you don't giving up some of the surface area you might consider doing a floating island. Essentially a floating planter. The roots of what you plant on it will grow into the water beneath and the take out nutrients. Diffusion and wind keeps the nutrients moving around so no power is required. Main drawback would be the loss of some of the pond's surface area.
It isn't what we don't know that gives us trouble, it's what we know that ain't so - Will Rogers
If I am understanding your set up correctly, a ram pump won't work for your purpose. If your wastewater runs into the bog filter, how are your going to pump the filtered water back into your pond? The intake for a ram pump must be on the high side - the pump gets its energy to operate due to gravity exerting a force on the falling water.
I think you are trying to beat physics and move water without an energy source. It can't be done.
I like jpsdad solution. A floating island is like putting a lower efficiency bog filter right into your pond. No energy is required for that solution.
Another solution is to tie your bog filter to the pond at the exact same elevation. You just need to pump water for circulation, which requires much less energy than pumping water uphill.
You could make a long, narrow bog filter in a semi-circle around your pond. One end is wide open to the pond, the other end has a narrow blockage to the edge of the pond. Put a water circulating pump at the blocked end with the discharge hose going over the blockage and back into your pond. There are little solar pumps on amazon to do that for less than $20.
Those are cheap pumps, AND will only run a few hours per day, but do you need 24/7 filtering?
If the concept works, then you could install a better pump after your first one inevitably wears out.