I have a small natural pond sitting in a gulch . Its lined by a lot of rock and naturally holds water well. It rises and falls with the seasons but never dries out. I setup a pump to use it as way to help water the orchard. Now that thats working i wanted maximize its water holding capacity. I actually dont know if it has any leaks , but would assume it has a ways to escape. What would be a good low cost way to reduce leaks .
Here is the pond at its lowest level, note its actually deeper than it seems - as the shape goes straight down. You can see on the rocks the high water mark where it hits in times with a lot of rain [img]https://imgur.com/a/DSTEEME[/img]
Your pond may be a surface water pond that has leaks, OR it may be a groundwater pond that is tied to the groundwater level of the subsurface aquifer where it resides. Both types of ponds will obviously fill up when rainwater is flowing down your rocky waterway.
I think the easiest way for you to tell the difference is to observe a condition where you do not get rain directly on you and you do NOT get flow in your waterway, yet the water level in your pond actually goes up. That would occur if rain reached the aquifer in its larger geographic basin and raised the water level of the entire aquifer. (In that case, we would not say your pond "leaks", but rather that you have a "groundwater pond". Your pond water level would go down as a drought or other people irrigating are using up the groundwater, or even seasonally as the plants and trees draw water from the aquifer. You could possibly isolate your pond from the groundwater level, IF you get excess water from your surface water flows.)
Is the problem that you sometimes run out of water to irrigate your orchard?
If so, I think a plastic pond liner would probably be the most cost-effective means of retaining water in your pool - IF it actually leaks. Prices run about $1.25 (American) per square foot for the quality Firestone 45 mil EPDM liner. (That would be about $13.50 per square meter.) You would need significantly more material than the surface area of your pool since it goes so deep and you also need some "edges" to hold the liner in place. (You might read up on pond liners if you think that might help?)
The high water mark looks to be a little higher than the downstream "dam" at the bottom of the picture. If your pool does not leak much, perhaps you could raise the "dam" to increase your pond capacity? (Or seal the leaks and water paths in the existing dam?)
Almost all of the pond fixes that are discussed on Pond Boss are for ponds in soils that can be altered with construction equipment. Your little pond appears to be in fractured bedrock. Sometimes the "fractures" are just localized jointing patterns and the bedrock will hold water. Other times, the fractures are extensive and will allow water to flow. The current location of Serbia is in an area that has been right at the tectonic plate boundaries for much of its geologic history, and has therefore been battered and beaten by significant forces. That probably makes it more likely that your fractures do leak if your pond is above the elevation of the local aquifer.
Sorry, I can't be of much help. Just throwing out some observations so you can better evaluate your local problems.
It all depends where you are. You can drive 5 minutes be on the other side of the mountain and get way more rain or the other way and be in a desert. We are actually in a "Dry land forest" , but im not sure exactly what inches are. I know that during the summer things go dry and crispy .
Thanks for you reply . The water hits some underlying underground rock and fills. It seeps in through local cracks in the rock. ONly when it rains REALLY hard does it actually flow like a waterfall feeding the pond. Thats pretty rare but happens. The very bottom is rock and seeps in via localized water ( ipumped it dry and saw it fill back up slowly) . Now the dammed up side goes up about like 10 ft from bottom , and there is no place visible for the water to go . The bottom is couple feet rock but then the bank has sections of gravel and soil. My guess is the bank leaks , probably not that quickly but I was thinking maybe i could add clay to these sections to make it seal up better.
The water hits some underlying underground rock and fills. It seeps in through local cracks in the rock.
The water seeping in through the cracks in the rocks WITHOUT any water flowing along the surface is the very definition of a "groundwater pond".
You cannot seal the cracks to save the water, because that is how the water usually enters your rocky pool.
The good news is that your shallow, rocky pool might be connected to a very large aquifer. Have you been able to use the irrigation pump for your orchard for several weeks without significantly lowering the water level in your pool?
If so, do you have any non-rocky ground near the orchard where you can build a pond? I am asking, because it might be possible to pump water at a low rate from your rocky pool into a newly constructed pond. That would give you a water supply that could still be used when the groundwater level in your pool recedes with the seasonal drying.
If you have sealing clay, you want your new pond to be as deep as feasible to store the most water while minimizing surface evaporation losses.
Ah awesome makes sense - this stuff is so fun . Water continuously flows and seeps into the pond but from the bottom and from uphill - ive seen tiny drips seeping form the rocks. I like the idea of pulling the water out before it leaks out the back side to a higher point . Thanks!