[jmhk]

Spring fed pond - Step 1: Planning

My kids have been trying to dig a pond by hand for the last year or two. Given the typical perseverence level of teens/tweens and the fact that the ground is hard-pan clay, I actually was impressed with their "progress" which was approx 12 foot diameter and 12-18" deep. We had our friend's Kubota this week to put in some drainage pipe, so my husband decided to give them some help. We now have a 12 foot diameter, 4 foot deep bowl-shaped pond dug - so the serious next stage planning needs to start.

It is located in an area that has a natural spring - it was wet nearly year round and in the springtime you couldn't even walk there without sinking into the mud. So should I be thinking about putting a liner in or just leave it natural bottom and let it start filling up? The expectation is that this will be a very lowtech setup - low stocking, native plants to the maximum extent and only solar powered aeration/pump. It receives morning and midday sun, but is shaded in the afternoon.

The only pond I have ever "owned" was a competely self maintaining one that my father/grandfather dug some 50+ years ago - it has some large goldfish in it that survived and bred all on their own during that entire time - no human feeding, no nothing, but it is more like 20x50 foot and 6 foot deep, out in the woods. It was fed by springs and ground runoff.

So hit me with your thoughts on how we should proceed....

 

[jmowbray]

First thing is if you are going to have it spring feed you need to find out what type of spring it is. Artesian, ephemeral, fractured.

 

[jmhk]

This area of upstate NY is riddled with springs. I believe they are considered artesian, but don't know if this one is seepage or fracture. About 300 feet across the hillside from this site, I have an old block laid springhouse with about a 10x6x5 foot reservoir that always has at least a trickle flowing from the outlet. During the springtime, the rate increases to the point that the 2 inch outflow pipe has 50-90% flow....

 

[jmowbray]

Does it consistently flow all year long even in drought periods?

 

[jmhk]

Although the springhouse flows all year long, I would not say it is consistent - it definitely slows way down in late summer/early fall. The area of the lawn is similar.

I think nature will give me the answer over the next few days - if it doesn't start self filling, then I will know that it would not work out in the dry season without a liner. We are currently just at the tail end of the drier season here.

 

[jmowbray]

Honestly if it was me I would use a liner regardless. There may be things in the soil good or bad that you most likely will not want. My thought is maybe put in a separate "well" and flow it into the pond. Also have an overflow on the pond. Therefore, you can feed the pond get rid of excess water and also have constant water in the pond. I just wouldn't chance it without a liner. I don't know exactly where you live (but do know that lakes as last week we learned about them in my Limnology class) but there could be chemical contaminants, clay (which will cloud your water, etc.) that you will hate yourself for later down the line.

 

[Diana]

Look into adding bentonite clay as a liner. It will seal the bottom well enough that the year round incoming water should be enough, though you are right to watch it now, in the driest part of the year.
If it even begins to fill, that is good.
If it seems that the water seeps away before filling, then add the bentonite to seal it.

 

[jmowbray]

Bentonite still has porosity though. It may still drain and if the clay isn't moist it may crack and you will have more issues. Nothing says fun like draining it once it's done and putting in a rubber liner.

 

[thelub]

Ducks are also great at creating a natural liner. When I was a kid we moved into a house that had a pond on the property. It never stayed full even though it had a constant source. Added ducks and within a few weeks it was full. Apparently duck poop is a natural sealer.

 

[jmhk]

Thanks everyone for the guidance.

The bentonite is an intriguing idea - I had never heard of it before and will need to find out its availability around here.

Though the ducks sound like an even more natural approach, I'm not sure that would be a good idea for this small of a pond (though my lab mix would surely love them). The ammonia load would probably make it toxic for any fish.

 

[thelub]

Yeah my pond was about 50' across and approx 10' deep. From time to time I'd see crappie and a what I swear was a weird crappie/goldfish mix

 

[acejohn]

This sounds like my dream place! Can you please take some pictures?

 

[jmhk]

Over the next 2 months after it was dug, the pond filled up to the natural soil level, but the water is seeping through the 18" bank that was created with the loose fill dirt. Everything is frozen and snow covered now, but I can't wait to get a liner set in the spring and finish it off. Nothing to do now but wait until it thaws in March.

<Edit> Here it is after the thaw...

 

[thelub]

If you have enough flow into the pond with grasses and other plants growing around it, I don't think the duck waste will create enough ammonia to be a problem for fish. It is getting a constant water change which should keep it in check.

 

[jmhk]

7 dwarfs would be nice about now....

The ice is out so it is time to get working. I picked up the liner - yikes is that stuff expensive! Then I started draining the pond while I excavated shallow end. Note to self: if you ever do this again, think about a shallow end while you still have the Kubota...:frown:


So here is what it looks like so far... after 5 hours of scratching out the hardpan clay.

It may be hard to envision, but here is the plan for what I have left to dig before I can set the liner, pump, waterfall and streambed.

 

[pweifan]

Looks great so far! You might want to put a few more steps at the deep end? That will give you many options when it comes to placing your pots.

 

[AGUILAR3]

Looking good. I like the bowl bottom. Easier to clean if you so choose to. Are you going to put any hiding spots for the fish?

 

[jmhk]

Good idea - a couple of partial ledges in the deep end might be easier for setting deep plants than putting them on concrete blocks. With it being underwater for a few months, it will depend on how soupy the bowl sides have become - it may not be possible to create a stable ledge in the already saturated section. There is already one rock ledge near the bottom - under the currently seen waterline - where I planned to set the pump. We hit a huge piece of shale that we couldn't remove without excavating a much larger pond than we wanted....

As for hiding places - I know where to get lots of free water lilies... and other native plants from the lake.

 

[Diana]

Go rent the smallest tractor they have. Dig it a bit bigger than you think you want.
When you add decorative rocks, boulders and so on it will shrink!

If it was frozen solid, all the way, then you will have to overwinter the fish in the garage or somewhere that does not freeze. Get a stock water trough that has enough capacity for this.
Otherwise look into pond heaters. They are not cheap to run!

 

[jmhk]

The time for powered equipment was in the fall. It will have to be handwork from here on - I sink in this area of lawn under my own weight this time of year. Any equipment would rip my yard to shreds.

Upstate NY gets cold, but not enough to freeze 4 ft deep. This was one of the deeper freezes we have had in the last 20 years and the lake still only had about 2 foot of ice. My husband works construction and the worst frostline we have ever had here was about 3 foot in a year we had no snow. Knowing the area fairly well, having lived here for half a century, that is why we dug it 4 foot deep.

We do know that some people in the area with shallow 2 foot ponds that lost all their fish this year and we do plan to use a bubbler to keep a small area open. Since that works to save the docks at the lakes, it should work on the pond, too.