Pond Boss Forums INTRO Questions & Observations Berm questions

I'm having my pond re-dug (cleaned and enlarged) and I've talked with a few contractors already but I'm not really sure what I want to do with the pond edge. I have a small dug pond with clay soil throughout, currently the pond edge is pretty much level with the surrounding ground. I have a small low area where water sometimes rushes in with heavy spring rains and brings leaves and debris from a small stand of woods that's low lying and near to the pond. My pond also overflows maybe once each spring with heavy rains but recedes quickly, usually in a day or two.

I see some excavated ponds where the pond edge is built up higher than the surrounding ground, I guess this is called a berm. When a dug clay pond is bermed up like that I assume that it doesn't get watershed and has to fill up with only rain? One contractor said my pond will never fill if I put a small berm around it and another contractor says it will. Does ground water move through clay at all? If there is enough rain, will the berm act like a bowl and hold the water above the surrounding ground?

I'm having a ledge cut 6' into the pond to hold cobblestone on the 3:1 slope. If I have a berm made I don't want it to be very high, but how high? Can I reasonably ask for the edge to be only 6" higher? My pond always fills to the top in the spring and during the summer, a normal summer, the water level usually drops about 12"-18" max. My stone will be only 6' in to accommodate for water fluctuations and I would like most of it to be under the water but I also want to be able to run my riding mower up to the stones. I want to keep the water as clean as possible.

Construction is scheduled to start next week, the pond was pumped in the spring and has dried up nicely. What should I do? Berm or no berm? A diagram would help greatly to show the contractor but I'm not good at drawing this out. I need help.

Loretta, can you post a link to an aerial map of your pond? Try Google maps or one of the multitude of aerial view services available online. That may help, especially if you can at least try to give us a good description of things in writing so we know what we're looking at.

As for the berm, I honestly don't know your answer. I was thinking, though, that if you have a low area where water will run in, you may want to consider making it into a wetland area that will filter a lot of the water coming in and slow it down so there is time for sediment to clear. Heck, you might even consider building your berm to add depth, then use that inlet area to serve as a surface runoff funnel into the your wetland area and then your pond. If you build the berm up around that area as well, so it acts as a catch area for surface runoff, you could possibly add depth that way. I'm probably not explaining this very well, but doggone it, I have a good picture in my head!

Let's see what the others have to say, but definitely try to find an aerial shot and then send us a link to it.

My pond is very small an an old aerial view doesn't do much good. Here is 2 pictures taken in March, you can see it's full.





The little woods on the left is where leaves and debris enter my pond with a heavy rain. I compost stuff in the woods too and I don't want that in the pond. When my pond overflows it does so in the area behind where the dog is laying in the second picture. The natural direction of water movement is from left to right.

You can see I have a berm behind my pond but it's higher than I would like around the rest of the pond. The berm really doesn't look that high in the picture but if you stand behind the pond, off of the berm, you can't see the water. I want to see the water in all other directions.

The new pond will be enlarged towards the spruce trees some and the berm will be modified. Unfortunately 5 spruce trees, one aspen and 2 pin oaks will have to come out to make room. My area is tight because there are buildings to the front of the pond. The new pond will be .25 acres (still small compared to most) and kidney shaped.

First off, beautiful pond, Loretta! I really like the setting you've got there.

In thinking about your berm, I guess the big question I have is why you are considering one. If the depth is not an issue for you, then I don't know of a really compelling reason to add a berm. Not that there may not be a good reason, I'm just not certain what it would be and that may help you get more meaningful input from those who actually know what they're talking about (which group most decidedly does NOT include me!).

Some other random thoughts:

* I bet you could have the excavator make you a low area in the place that runs into your pond so you could develop a wetland there. Catmandoo has a good explanation of what he did to create a wetland/filtration area in this thread. He may find some time to chime in with more detailed thoughts, too.

Creating that sort of buffer zone should help you eliminate the inflow of some of the stuff in the woods, especially since you compost there and may not want the byproduct ending up in your pond. Plus, a wetland may add some biodiversity to your wonderful setting you've already got there.

I guess ultimately I'm thinking you may not necessarily need a berm and don't know that it would serve any particularly good purpose, especially if you create a buffer zone to help control the contents of surface water inflow.

Let us know your thoughts.

Thanks Todd. I'm considering a small berm to block the icky water from entering my pond and to keep it from overflowing. Hoping for cleaner water. The pond overflowing isn't a big deal as it's so temporary but the woods is pretty much wetlands, it stays wet once the rains start in the fall through the spring and dries up during the summer. I put yard waste in the woods and one year after a heavy rain I had pumpkins discarded from the garden floating in the pond! Deer and other wildlife visit "the pile" in the woods.

The water doesn't look bad in the pictures but it gets pretty nasty after the icky water runs in.

Well that sounds like a perfect reason to build a designed wetland area, then, Loretta. When it's set up the right way, the wetland area serves as a filtration system for all the water entering your pond and will yield results far more useful to your pond than a berm would. Definitely see what the real experts have to say on this, but for my money, I'd put some thought and effort into constructing a wetland that will do the job for you (which includes keeping pumpkin shells out of the pond!).

I'm not sure I understand what a buffer zone is. The woods is lower than grade now, I want to create a clay barrier between it and the pond. Nothing will grow in the woods, it's too dark from all the trees.

I appreciate your input Todd and hopefully I will hear more from others.

Oops, I just noticed your link, going to read it now.

The link may help explain it a bit more, but if the woods area is already lower, then you may need to do some more earth moving to create an impoundment area that can filter the water somewhat before it enters your pond during those higher water events.

I definitely think we need to hear from others on this so you get a good, balanced set of ideas to help you figure things out! I've got to duck out for awhile now and go earn a little money, so now will be a good time for the moderators to strike my useless posts and insert some real content! I look forward to seeing what other input you get, Loretta!

Ok, I think I understand buffer zones. There is no room for a buffer zone between the woods and my pond. Right now there is about 10 feet separating the two and that will be reduced a couple of feet when the edge is cleaned up. I'm removing 2 pin oaks in that area already to make more room.

Thank you Todd, have a good day.

Loretta, beautiful setting!!

You metioned that you do not want the pond to overflow. You also said that the pond dried nicely after being drained.

If your pond drained, and if you don't pump water into your pond to fill it, your pond is entirely dependant on runoff (the watershed) to fill. If you had a ground water source for the pond, it would have never dried, but re-filled once pumps were shut off. Putting a berm around it will prevent water from entering and give you an empty hole. I'd like to know how the contractor that says the pond will fill with berms built thinks the water will get in there---he is simply wrong (or will build a low spot for inflow).

As for overflow, without a ground water source to flush the pond, overflow is essential for a quality pond to flush out waste and other natural "pollutants".

Those spruces are beautiful, but should not have been placed on the dam (current berm) as the roots will eventually die and rot which will lead to severe leakage in the pond. Behind the dam may not look as nice, but would be far safer.

The aerator boil I see will quickly decay any of the leaf litter entering your pond so it is more of a non-issue as far as water quality is concerned. The compost debris is a little different. Could a small berm" ditch be built to channel any runoff from the compost away from the pond? Perhaps a very small ditch and a relocation of the compost would work.

Hi Rainman, thanks for you response!

I was thinking the same thing, if my pond had a berm I will only get 32" of annual rain and 12"-18" of that will evaporate.

I know very little about the properties of clay but I mostly wanted to know if water moves through it at all. When the ground (clay) is saturated in the spring, water still doesn't move through it? The reason I ask is because I have an old shallow well (not for household use) that's 4' in diameter and about 9 ft. deep, it's lined with rocks and fills up with ground water but I don't know if the water is coming from the top of the well or seeping in from the sides (all rocks are wet with trickling water). I keep the water pumped out of it in the spring and this helps dry my grass up earlier to mow. After a heavy rain I can pump it several days in a row, it continues to fill up. The well is covered with a cement slab about 5' x 5' with an access hole.

Also, in the spring when the ground is saturated, if you dig a hole (say 2' deep) it will fill with water. My pond won't fill up in this manner?

I don't mind the occasional pond overflow so much as my property is wet all over in the spring anyway. I mostly want to stop the inflow in one area so I may just have that part by the woods built up a little so when the woods overflows it will do so on the grass.

Without seeing the subtle lay of the land or a clear topographical map, I can't tell you much about how to control/re-route any drainage.

I can say that since your pond holds water so well during the summer tat the clay in the pond was well compacted and is "sealed". If groundwater in the spring entered your pond through the clay, the water in the pond would drain by the same path.