Wildlife Pond

BUILDING A WILDLIFE POND

From Theresa

So far, building a pond has been my favorite and most rewarding garden project. It's one of the best things we've done to create habitat in our tiny yard, as water is the one essential habitat element that benefits all wildlife. For us humans, the pond is fascinating to watch. It is an entrance to another world, one in which humans can't live, even though we are made mostly of water. It is the most mysterious part of our yard, so I am drawn to it more than to any other part of the garden. Having a pond outside our door lets me observe and interact with wildlife I wouldn't otherwise see.

A wildlife pond has some major differences from other types of backyard ponds:

It doesn't have a pump: Pumps will kill small wildlife, such as frog tadpoles, as the pond water is sucked through the pump. The water disturbance that pumps create is also hard on some wildlife, such as dragonflies, that prefer to breed in still water. Most people think a pond needs a pump so that the water doesn't become stagnant and smelly, and won't breed mosquitoes, however, circulating the water through a pump is not the only way to deal with these issues (see the Pond Maintenance section below).
You put dirt in the bottom of the pond: Most ponds constructed by humans have only rocks or gravel at the bottom and the plants are grown in pots. The pots are removed in the Winter and stored indoors, and the plants are repotted into larger pots each Spring. This was way more work than I wanted. Fortunately, in a wildlife pond you add actual dirt to the bottom, in order to create better habitat for animals, and in which you can grow your plants.
It doesn't have exotic goldfish: fish will eat frog eggs, and I wanted frogs in our garden because they help keep the garden ecosystem balanced by eating insects, beetles, slugs, and snails.

If you're reading about ponds or talking to staff in pond shops, you probably won't find much support for constructing your pond this way. In fact, like me, you might be told that it's impossible to maintain a pond like this. However, you can find a few wildlife books that tell you this is the best way to build a pond, and it has worked for us thus far.

Pond building is not very hard- I did most of the work on this pond during my week-long Spring vacation in 2012. Bear helped when he was home from work in the afternoons, and was essential for the heavy lifting. Below I share what I gleaned from books, online sources, and my own experience about how to build a pond. I've included lots of dos and don'ts that may seem complicated, to help you build the most easy maintenance pond possible, that will benefit the most wildlife. But in the end, build whatever you can, even if it doesn't follow all the rules (which is what we had to do). Even if all you can do is dig a small hole, cover it with pond liner, and fill it with water, do it and see what happens. It may need extra maintenance or not last as long as a more complicated pond, but it will provide important habitat and give you the joy of interacting with more wildlife.

Contents:

POND BUILDING STEPS:

Choose & Prepare Your Location
Pond Design
Rough Dig the Pond
Leveling the Edges
Smooth the Pond Bottom and Sides
Install Padding to Protect the Liner
Buy the Liner
Install the Liner
Fill the Pond with Dirt, Rocks, and Water
Building a Privacy Trellis Behind the Pond
Adding a Frog Condo
Adding Rocks Around the Pond
The Finished Pond, Year 1, June 2012

OTHER POND INFO:

EDIBLE AND USEFUL POND PLANTS
POND MAINTENANCE
WILDLIFE and the POND
WINTER MAINTENANCE: KEEPING THE POND UNFROZEN
SPRING CLEANING THE POND
THE POND IN LATER YEARS

1. Choose and Prepare Your Location:

Things to consider when deciding where to put your pond:

Most pond plants need full sun, so put your pond in a sunny area if you can.
Check the location of your underground utilities to make sure you won't run into them when you're digging. In Wisconsin, see www.diggershotline.com. Contact the digger's hotline and they will come to your yard and mark where the underground gas and electrical lines are. We had to contact our village office to find out where the water & sewer lines were (although they gave us the wrong information- it's a good thing I didn't put the pond where I initially planned to, which we later found out is right over the main water line).

Try not to put your pond:

Where it will get herbicide or pesticide run off.
Near a tree, because you might run into big roots when digging it, and it will get full of leaves in the Fall.
Near bird feeders, so that bird seed doesn't fall into the water (ours gets a lot of bird seed blown into it when there's a strong wind).
Near walnut trees. Walnut trees drip a toxic substance that is meant to keep nearby plants from growing and competing with the tree. One book I read said it would kill everything in your pond. However, we have not had problems with this. Our pond isn't under our walnut trees, but it is close enough that it gets nuts and leaves from the walnut tree in it in the Fall. It hasn't had any effect on the pond that I've noticed, except that it sometimes has walnut oil floating on top of it.
Don't put it right next to your foundation- it's just wise to keep water away from the basement.

It's very important to make sure you'll be able to see your pond, so you can enjoy the wildlife that will utilize it:

You'll want space for putting a bench or other seating (I have large tree stumps) right next to it, so you can look down into the water and see the small bugs, snails, and other things I can't really identify, that will be moving about under and on the water.
If you have a deck or patio, you might want to put it nearby, so you can easily watch it.
If you can locate the pond where you can view it from inside your house, you'll get even more enjoyment out of it. Animals will be more likely to come to the pond when you're not outside and you can watch the pond during the Winter months too.

a. We decided to put our pond in our side yard, next to our Celtic Cross Garden. In the photo to the right, our future pond will be in the middle left, in front of the tree stumps under the bird feeders. This is across from the dining nook we built in our bay window, so we can watch the pond while we're eating. There were several disadvantages to this location, but there really wasn't any other place to put it in our yard that would let us enjoy it from inside the house. It's just outside the drip line of our walnut trees, so leaves and nuts do make their way into the pond.

To prepare your chosen location:

b. Remove the grass, if necessary, from your pond site. Since our pond would be in a small area, Bear just dug up the grass (click to see other options to remove grass). You can see in the background where we already built a small berm of turf that we dug up from elsewhere in the yard. It's covered in black plastic weighted down with rocks and logs to keep weeds away.

c. After removing the turf, we covered the entire area with black plastic to keep the weeds from growing until we were ready to start constructing the pond.

2. Pond Design:

To Create the Most Habitat:

The more variety you have in your pond, the more habitat it will create.
More edge creates variety. An oval shape will have the least edge. An irregular shape with curves and inlets will have more varied spaces for different habitat to develop, and will look more natural.
Also include different depths for more habitat (see below).
One books said that a pond without a pump and filter needs to be at least 43 square feet in volume to create a balanced environment, so shoot for that if you have the space.

Include a Shallow End/Beach:

There should be a shallow, open end without large rocks or vegetation, at which you create a beach area for wildlife to access the pond.
The beach will be used for drinking by a wide variety of animals and birds will use it for bathing.
The shallow end should be about 4-6" deep, and have a gradually sloping beach that will allow frogs and other wildlife to enter the water.
Add stones around or near part of the beach area that are flat or large enough for birds to land on or to sit and prune themselves after bathing.

Above are some pond shapes and below is a cross section of a pond I drew while I was thinking of possible pond designs.

Include Shelves Around the Edges:

Most people build underwater shelves along the sides of their pond. This increases habitat by creating different depths.
Shelves support pond plants that aren't happy in deep water and may be used by frogs for mating.
Recommendations for the size of side shelves vary, from 8-12" deep, and 9"-12" wide.

Include a Berm if you Want:

If you're making a larger pond, you'll be digging up a lot of soil. Decide what you'll be doing with it. You can pile it around the pond on one or more sides to create a berm or small hill. The berm can be planted, creating more habitat and a visually pleasing backdrop for your pond. Just make sure it doesn't block your view, and try not to make it so steep that it looks unnatural.
The berm can also be used to direct any overflow of water that might occur during heavy rains. Bear was quite worried that the pond would overflow and make our basement wet, so I made sure there was a depression at the shallow end where the overflow would run. I built a trench to direct it into one of our rain gardens, which I thought was a great use of resources. However, even during one of our wettest months on record, the pond was very full, but there was never any noticeable water running away from it.

Include a Deep End:

The deep end will give pond animals places to hide from the predators that are also drawn to ponds, and room to go about their business.
It will allow you to grow pond plants that need deeper water.
If it's deep enough to be below your frost line, it will give wildlife a place to hibernate and help plants survive the Winter.

How Deep Should the Pond Be?

Generally, my books say aim for at least 2 feet deep and ideally 3 feet deep to benefit the most wildlife. But you'll also want to consider where the frost line is in your area, which is the depth at which the moisture present in the soil is expected to freeze. Some pond animals and plants need to be below the frost line in order to survive the Winter.

It seems to be difficult, though, to find definitive information about where the frost line is. I emailed my county extension office (which I found by searching online for "Iowa County extension office Wisconsin"), but they were not able to answer my question, and were very discouraging about how steep the sides of my pond were likely to be given my pond dimensions. Other information I found online said that the deep end of the pond should be at least 2' if you're in gardening Zone 5 (which is us), or at least 3' for Zone 4.

I should probably have tried to contact the building inspector for our village, who would know the building code requirements for how deep you need to build foundations so they don't suffer from frost heave. But in the end it didn't matter in our situation. To build a deeper pond, you need to increase the width of the pond so that the sides aren't too steep. We had only a small area in which to build, so we just built the pond as deep as we could. I got to 2 feet.

How Steep Can the Sides of the Pond Be?

Generally, the sides should slope as gently as possible to insure that they won't collapse. Specifically, the information I found said this:

the sides should be 20 degrees from vertical
the sides should drop at a rate of 1/3 of the equivalent distance travelled across the top to assure stability

I ended up building almost vertical sides in the deep end of our pond, however, in order to get more depth, because I wanted frogs to be able to hibernate there. Our soil is clay, though, which gives the walls pretty good strength on their own. Several years later they still haven't collapsed, but I do worry about it sometimes, so I don't recommend doing this unless you have to.

Mark Your Pond Design on the Ground:

When you're ready to design the pond at your chosen location, use something to mark the shape on the ground. In this photo, I've used landscape paint from a spray bottle that I bought when I was less environmentally conscious. You can use flour, corn meal, rope, or possibly a hose (but it doesn't seem like a hose would let you make a lot of curves).

As explained above, the more curves you can get into your design, the more natural it will look and the more habitat it will create. I drew a lot of really complicated, curvy shapes on paper when planning my pond, but when I was actually marking it on the ground, I realized we had too small of an area to include lots of curves. Also, more curves can make putting in the pond liner more tricky (you'll have to do more folding). So I ended up with the simple, but at least not oval, shape shown in the photo to the right.

3. Rough Dig the Pond

a. When you've finalized your design and marked it on the ground, start digging. Try to set aside the top soil (in buckets, on a tarp, or just make a separate pile) so you can put it back around the edge of the pond at the end of the project, as it is the best soil for growing plants. You can usually tell the top soil from the deeper soil because it has a different color and/or texture.

b. Keep digging. You can see in the top end of the pond below where I got below the browner top soil and hit the redder clay beneath. You can use the non-top soil dirt to create a berm, which we've done on the right side of the picture below.

c. If you run into roots, use a pruning saw (second tool from the right) to cut them a couple inches back into the soil so they hopefully won't poke out through the liner later. You can reach back into the soil with the blade of the pruning saw to cut the root, you don't have to dig back that far.

d. Our cat Frost helps with the digging. He's laying in a planting pocket I made. A second pocket is across from him at the top of the photo. This is how I tried to put side shelves in my pond. I wanted to put my plants directly into the soil rather than leave them in pots, so I tried digging two "pockets" or indentations on the sides, into which I put the liner and covered it with soil. I did plant arrowhead in these pockets the first year, but the pockets were so small, the arrowhead jumped ship pretty quickly. I think this idea might work, though, if you could build a bigger pond that would accommodate larger pockets.

4. Leveling the Edges

The edges of the pond must be as level as possible. If they're not, the liner will stick out above the water where it will be exposed to UV light from the Sun, causing it to degrade faster. It also doesn't look as nice.

Making the pond exactly level is much easier said than done, though. To see how close you are, place a carpenter's level on top of a piece of wood, such as a 2x4, that's long enough to go across the pond. Adjust as needed by adding or removing soil. We needed a short piece of wood to go across the narrow width of the pond and a longer piece of wood to test the entire length of the pond. In the picture, I've also put a yellow yardstick against the level in order to see how deep I've gotten the hole dug.

In the end, I apparently did not manage to get the pond perfectly level. Some of the liner shows in the deep end, which I try to shade with plants. The shallow end loses water more than I want it too, so I think I did not get the pond level along the long end. Or maybe I have a leak near the top. Do the best you can.

5. Smooth the Pond Bottom and Sides

After you have the basic hole dug, remove all the rocks or anything sharp, and smooth out the sides and bottom of the pond as much as possible. You want the dirt to be smooth so that nothing sharp pierces a hole in your pond liner.

a. Below are the tools I used for the pond project: the regular shovel (left) was for the major digging. Second to the right is the pruner saw discussed above. The straight end shovel (right), I used to start smoothing out the bottom and sides of the pond after I did the rough digging. I did most of the smoothing with the tool second from the left, which is a Japanese gardening tool with a triangular head that works kind of like a tiny hoe. It's very sharp and allowed me to scrape the dirt to smooth it out. After you scrape the edges during smoothing, you have to dig out by hand what's fallen to the bottom.

b. To the right you can see the smoothed shallow end at the top of the photo as compared to the still rough end at the bottom.

It was possible to get the shallow end this smooth because our soil has a lot of clay in it. In fact, it reminded me of the times in my life when I've sculpted, and this part of the project became really enjoyable. It was like making a large Earth sculpture.

Below are a couple shots of the pond after I scraped all the edges and removed the loose dirt. In the left photograph, you can see that the walls in the deep end are much steeper than they're supposed to be, but it worked, I assume because there's so much clay in our soil.

6. Install Padding to Protect the Liner

To further protect the liner from punctures, such as when you need to walk in the pond to do maintenance, you should also install padding under it. You can buy padding, called underlayment, from pond shops that sell pond liner. Alternately, you can also use wet newspapers, old carpeting, and/or sand.

We used newspaper, because we were able to get unsold papers in quantity from Bear's place of employment. Here's how it works:

Try to get a 1/2" thick layer of newspaper.
It's best to unfold the newspaper to its entire length. This is a big job, so I recommend doing it before hand. Bear did a lot of it for me while he was watching TV.
He measured the papers into 1/2" thick stacks and stored each stack criss-crossed so I could easily tell that I was putting it on thick enough.
As you're installing it, wet down the paper to shape it and keep it from blowing away.
If it's hot out and your pond is big, keep hosing down the newspaper as you work, or cover the finished part with plastic to keep it wet.

I found this to be another fun part of the pond project, even though it was a bit exhausting, because it was like a big paper mache project.

a. I started adding wet newspapers to the shallow end. You can see the water you need to add makes mud puddles.

b. Here I've covered the shallow end in plastic to keep it protected while I worked on the deep end.

c. The deep end almost done.

d. The pond with all the padding installed.

7. Buying the Liner

I waited to buy my liner until I had the pond dug, since I wasn't sure before hand what size it would end up being. The liner size is determined by the length, width, and depth of your pond.

To Determine the Size of Liner You Need:

Length: Take the longest length of your pond and add 4' (which gives you 2' extra on each end)
Width: Take the widest width and add 4' (which gives you 2' extra on each side)
Depth: Double the depth of the pond (which accounts for going up and down both sides) and add the depth to both the length and width

Example for an 8' long by 5' wide by 3' deep pond:

Length- add 4' to the longest side: 8+4=12
Width- add 4' to the shortest side: 5+4=9
Depth- double the depth (3x2=6) and add it to both the length and width:
12+6=18 and 9+6=15
So for a 8'x5'x3' pond you need a 18'x15' liner

Our pond was 7 feet long, 4 feet wide, and 2 feet deep, so we needed a 15'x12' liner, or 180 sq. ft.

What Type of Liner to Buy:

You can buy rigid plastic forms to use in pond building, but these instructions are for building a pond using a flexible liner. Below are the types of flexible plastic liner I read about and/or came across. Some of my books were old, so I'm not sure if all of these actually still exist, or if there are others currently available:

EPDM rubber- This is the type I ended up buying from a pond shop. It comes with a 20 year warranty, is UV resistant and non-toxic to fish. It's very thick, so is harder to tear or puncture. It cost about $1 a square foot when I bought it in 2012.
Butyl liners- Are supposed to last 50 years and cost about $2 a foot. I didn't find this for sale anywhere in our area.
PVC liners- These are considered to be reasonably tear resistant and some are guaranteed for 10 years, but they're not supposed to be exposed to sunlight or they degrade.
Pond Liner at Home Depot- I found some of this in their garden section. It came in packages of specific sizes. It didn't say what type of plastic is was and it seemed very thin. However, if you don't have a lot of money, it's probably the cheapest you can find. It just may not last as long. The salespeople also tried to sell me roofing rubber and said it was the same thing, but I wondered if it was fish safe? On the other hand, what do they do to the EPDM rubber to make it safe for fish?

Shopping for the liner after reading about the above types was somewhat challenging. Even one garden center that was well-known for installing ponds couldn't tell me what type of plastic they used for their pond liner. They seemed to expect me to just trust it because they used it.

Cost:

We bought our liner from the Paradise Pond Shop in Cottage Grove, WI (www.ParadisePondShop.com) which was the only pond shop I found in the area that sold retail and could tell me that they had EPDM rubber. The liner we bought from them came on a roll, so I had to buy it in that width. So I ended up with 240 sq. ft. at $.86/foot, which cost $218.00. This was the most expensive part of the pond project. Our only other expenses were the cost of the truck rental ($25) to haul the edging rocks, and the cost of the plants.

8. Install the Liner

The liner for our pond was extremely heavy, so you may need help for this step. I couldn't have lifted it myself, but Bear was able to.

It helps to lay the liner in the Sun before installing it (but not on any grass or plants that you don't want to be killed). The Sun will warm up the liner, making it more pliable and easier to work with. Store it in the shade, though, until the day you're ready to put it on the pond, as UV rays can damage it.

a. To get your liner onto your pond, lay it out flat and role it up like a tortilla, which Bear is starting to do below. Carry it to one end of the pond and unroll it the same as if you were putting a pie crust in a pie pan.

b. Push the liner down to the bottom of the deep end of the pond. Begin molding it to the sides and folding it into creases to make it fit- like gathering fabric to sew pleats.

c. Weigh down the folds and bottom and edges to keep the liner in place while you work (I used rocks). You can also put a couple inches of water in the bottom of the pond to hold the liner in place.

This is not an easy part of the project. Do the best that you can. When you add water, everything will get flattened into place. And don't worry much about how all the folds will look. They will quickly get covered in natural pond muck and you won't see them.

9. Fill the Pond with Dirt, Rocks, and Water

Determining Your Pond's Water Volume: Before you fill your pond with water, note down your water meter reading. Then note the reading after you've filled it with water. The difference will tell you how many gallons of water your pond holds, which can help you determine how many plants and animals your pond can support. I made a mistake when I was doing this, and recorded the reading on our old water meter, completely forgetting that our village had recently installed new ones. If your pond is less irregular in shape than ours, you can also determine water volume this way: one cubic foot of water is 7.5 gallons, so the pond length x width x depth x 7.5 = the pond volume.

Pond Soil: I've read that clay is the best soil to put it in the bottom of a pond because it stays soft in water. That's what we have in our yard, so that's what we used. 6" of soil on top of the liner is supposed to be enough for plants.

Pond Water: Rain water is best to use for filling your pond, if you have a lot of rain barrels or if you're really good and can time your project so that it just happens to rain a lot right after you install your liner. If you need to use municipal water that is chlorinated, like we did, it should sit for several days in the pond to let the chlorine evaporate before you add any plants or animals.

a. We shoveled approximately 6" of clay dirt into our deep end (we just used some of the dirt we had dug up) then filled the deep end with water from the hose. The water will look muddy at this point, but the dirt will settle and the water will clear up.

b. I used river rock (medium sized, rounded stones with no sharp edges) in the narrow middle of the pond, and pea gravel (tiny rounded stones) in the shallow beach area. I used larger stones as terracing, to keep the pea gravel from from sliding into the deep end. Both river rocks and pea gravel can be bought in bags from the hardware store if you don't have another source. Just make sure you don't use any sharp edged rocks that could pierce the lining. I included lots of rocks because it creates more niches for habitat and I read that the more rock surfaces there are in a pond, the more the algae stays in control.

c. Keep filling the pond with water. Begin removing the rocks from the outer edges of the liner.

d. Let the liner settle for a bit before cutting off the excess around the edges.

e. Trim the excess liner, leaving about a foot around the edges. You'll be able to tell if the pond is level by whether there is any liner showing above the water (ours looks level, doesn't it?). To some extent you can remove dirt from under the liner to level it out. Then cover the liner with dirt. It's pretty impossible to make a totally smooth transition between the liner and the dirt if you have steep sides like we do. You can see the liner showing a bit below. This can be shaded by plants, or covered by letting edging rocks stick out over the water a couple inches.

Wow, it's a pond!

10. Building a Privacy Trellis Behind the Pond

As you can see, we built our pond in our narrow side yard, right next to our neighbor's driveway and back deck. We wanted to install a privacy trellis to provide a better looking backdrop for our pond.

a. Bear is leveling metal footings bought from the hardware store that he pounded into the ground.

b. We slipped four white PVC posts into the metal footings and attached them with screws.

c. Between the posts we installed brown plastic lattice.

d. Now we can grow plants on the trellis for privacy.

Trellis Cost: We got lucky one day and found the 4'x4' white posts on sale at Habitat Restore for $10 a piece (the Restores are Habitat for Humanity's architectural salvage shops- there are two in Madison). I think the metal footings were around $5 a piece. The plastic lattice we also had to buy new- at around $20 a piece.

Trellis Design: Our posts were 6' tall and our lattice was 8', so I cut the lattice into triangular shapes at the top, which was easy to do with a jigsaw. I didn't want to lose the extra 2 feet, since our neighbor's driveway was so much higher than our side yard. However, this probably wasn't the best plan, as the triangles started falling over when they got their first heavy vines on them, and we had to reinforce the lattice with the edging that is sold to go with it. It still won't hold a really heavy vine, though, unless we figure out a way to support them even more.

11. Adding a Frog Condo

I wanted to create shelter for frogs and toads near the pond. They like shady and cool places to get out of the hot sun, and some hiberante by digging into the ground. I created this frog condo to try and meet these needs, based on some suggestions I found in wildlife habitat books. Unfortunately, I put the condo near the deep end of the pond. If I were doing things over, I would put it near the shallow end, as it would be much easier for the frogs to access there. They can exit the pond most easily from the shallow end, and a lot of vegetation has grown up between our beach and this condo. If you want to build something more simple, a mound of twigs and leaves at the edge of the pond will also provide shelter.

a. I placed some old clay pots half-buried on their sides, up against the berm we had created behind our pond.

b. I positioned rocks on and around the pots to make chambers between the pots where the frogs could also hide and/or dig deeper.

c. I completely covered the pots with rocks, leaving two tunnel entrances near the front of the rock pile.

d. The finished frog condo. I put a branch on the edge of the pond, sticking into the water, hoping it would help frogs exit and enter.

12. Adding Rocks Around the Pond

The liner at the edge of the pond should be covered either by rocks or soil and plants to protect it from the Sun. If you're adding rocks, which we did because they just look cool, consider the following:

Leave a space on the pond edge where you can kneel to do pond maintenance.
The stones should have texture so they don't get slippery.
If you have the right type of stones (flat), you can place them so they extend over the the pond water by 2" so liner can't be seen.
When laying the stones, create as many nooks and crannies as you can in which creatures can shelter and try to arrange the stones to make shady spots for amphibians to get out of the Sun.

If you're using plants around the edge of your pond instead of stones, consider whether you have enough soil coverage over the liner to support the plants you want to use. You may need to use small ground covers right next to the pond.

We don't own a truck that could carry really heavy rocks, so we rented one from Home Depot. In 2012, it cost around $20 if you brought it back in less than an hour and a half, plus an additional charge if it took longer.

We had a bit of an adventure with the truck. They come with an alarm that goes off when you've loaded the truck too full (it held 2000 pounds). Rocks are heavy so we had no idea how many it would take to set off the alarm. We didn't have any trouble with it while we were loading the rocks onto the truck and driving them about 30 miles to our house. But when we pulled into our driveway, the alarm started going off. It was very loud, like a car alarm, and it was hard to stand next to. It didn't go off when Bear turned off the truck. We couldn't figure out how to make it stop. Bear ran inside and called the store while I tried to frantically unload rocks, but since they were heavy, it was slow going. It was such a relief when the sound stopped. Home Depot gave us a discount on the rental for our troubles, so we were happy.

a. We got these lovely landscaping rocks from our friend Deb, who had a pile of them in her yard that she wanted to get rid of. We just had to dig them up and haul them away. They were quite heavy, so this was not an easy task, but it was sure worth the effort to be able to use them on the edge of the pond.

b. The truck comes with this loading ramp that has ridges across it. To get the really large and incredibly heavy stones onto the truck, we levered them out of the ground with a crow bar and positioned a dolly underneath them. Using the wheeled dolly, Bear pulled the rocks up the ramp, while I tried to push. We needed to lean on the ridges part way up and rest, because they were too heavy to pull all the way up at once.

c. Bear's so tired from moving rocks, he's napping on them. No, he's actually installing our largest rock that only he can manage to move.

d. A before shot, with only a few rocks installed:

e. Some after shots, before the plants grow in. Remember to leave as many nooks and crannies as you can
to provide habitat for small amphibians:

I love arranging rocks. Each one has its own beauty. I seem to have an instinct about where each one should go,
although sometimes I do have to rearrange them a few times until it feels right.
Take your time listening to your rocks and maybe they will tell you where to put them, too.

13. The Finished Pond, Year 1, June 2012

Here's the pond in its first Summer, after the plants have grown in a bit:

Here's a shot that shows the trellis with morning glories growing up them:

OTHER POND INFORMATION:

1. Edible and Useful Pond Plants

I still have a lot to learn about pond plants. So far, nothing I've grown in the pond has managed to survive the Winter, except duckweed, which is apparently one of those plants that can't ever be completely eradicated, so I can't take any credit for keeping it alive. Here's what I know about water plants so far.

Plants are a necessary component of the pond eco-system. They shade the water and help keep it from growing excessive amounts of algae. Plants also oxygenate the water, which helps keep it from getting stagnate and smelly. Plants on the edge of the pond provide cover and shade for amphibians.

Perhaps the hardest thing to digest about pond plants is this:
Most of the pond surface (2/3 to 3/4) should be covered in plants.
So, yes, after you build a wonderful water feature, you need to hide most of the water. The shade provided by the plants is an important component in preventing algae blooms, especially in ponds without pumps.

The next thing to understand about water plants is that there are several types, and each plays a different role. The most balanced pond is likely to have most of these types.

Types of Pond Plants:

Filtrators: these plants absorb nutrients so that algae doesn't grow in excessive amounts. Examples I've read about (in no particular order): Parrot's Feather (Myriophyllum scquatica), Elodea Canadensis, water lettuce (Pistia), water hyacinth (Eichhornia), water mint (Mentha aquatica), watercress, water iris, cattails, arrowhead (Sagittaria species), papyrus, umbrella plant (Cyperus species).
Submerged: the leaves of these plants grow under the water, so they breathe in carbon dioxide and breathe out oxygen. These oxygenators are some of the most important types of plants to have in your pond. They help keep the water from becoming stagnant and smelly.
Floating: these float on top of the water and help prevent algae blooms by shading the water. Their roots dangle in the water and help absorb excess nitrogen and phosphates. Most floaters are annuals (except duckweed).
Water-Lily Like Plants: these grow in the soil under the water, but their leaves float on the surface of the water (lilies) or rise above it (lotuses and arrowhead). Their large leaves shade the water and can provide landing pads for wildlife.
Marginals: these grow at the edges of ponds, in either moist soil or shallow water. They are good transitional plants between the pond and the rest of your garden.

Duckweed & Water Hyacinth

Floating Water Plants:

To the left is duckweed (the tiny plant on the surface) and water hyacinth (the larger, bulbous plant), both of which float on the surface of the pond and trail their roots into the water below. Water hyacinth is prolific- two plants thrown into the water in the Spring covered the surface of our small pond by Summer. Don't let them escape into the wild, where they can choke waterways.

Water-Lily Like Plants:
The plant in the foreground with leaves shaped like an arrow is appropriately known as arrowhead (Sagittaria species). Its roots are in the dirt at the bottom of the pond, but its leaves rise a foot or two above the surface. Their height provides a good vertical element and emerging dragonflies use their stems to crawl out the water (see more below).

Planting:

These are planted directly into the dirt at the bottom of the pond. When I put in my first plants, only a week after filling the pond with water, the dirt already felt like normal muck at the bottom of a real pond. The boulders were already stuck in it and hard to move.
I recommend putting some small rocks around the plant, so that it stays in place under the water until the roots grow enough to support the plants. I've had a lot of arrowheads fall over on me and need replanting.
It's okay to totally submerge the leaves of the plant- you'll be amazed at how quickly they grow to reach above the water.

Arrowhead- in 2015 they finally overwintered and then proceeded to entirely fill the pond, but that's okay because they have edible tubers.

Marginals:

Grasses, sedges, or rushes provide good wildlife cover at the edge of ponds.

Edible Pond Plants:

As a permaculturist, I am always trying to grow perennial plants that I can eat. I was surprised to find that a lot of water plants are edible. Here's a list of those I've read about, plus my sources so you can get details about how to grow, harvest, and eat them. I can't speak from experience, as I haven't yet managed to eat anything from my pond:

Arrowhead (Sagittaria latifolia, see photo above): these submerged plants have edible tubers that were used by Native Americans.
Water Lotus (Nelumbo nucifera): In addition to being incredibly beautiful (I love the way rainwater beads on the surface of the leaves, and the flower is supposed to be very fragrant), lotus root is edible and used in Asian cooking. The plant should survive the Winter if the root doesn't freeze solid.
Cattail (Typha species): has edible tubers and shoots, as well as many other survival uses
Water Celery (Oenanthe stolonifer): has leaves like celery
Water Cress (Nasturtium officinale): has edible leaves
Water Chestnut: has crisp corms that are used in Chinese cooking
Duckweed (Lemna species, see photo above): is eaten raw if taken from really clean water

Here are the two sources I've found for information about edible pond plants:

Perennial Vegetables: From Artichoke to “Zuiki” Taro, a Gardener’s Guide to Over 100 Delicious, Easy-to-Grow Edibles, by Eric Toensmeier. ISBN: 978-1-931498-40-1. $35. This book has a section on "The Edible Water Garden" and describes how the author grows edibles in pots in a kiddie pool. It also has in-depth descriptions of many of the individual plants.

Toolbox for Sustainable City Living by Scott Kellog and Stacy Pettigrew. ISBN: 978-0-89608-780-4. $16. Has a section on plant aquaculture, but also worth getting for everything else in the book.

Other Pond Plants:

Here are some pond plants I've read about that sound good for Wisconsin, but I haven't tried yet:

Common Waterweed- this is supposed to be the best submerged plant for Wisconsin. To plant them, just throw them in the water. They should sink and root among the stones or soil.
Coontail- this floats and never needs potting. In Wisconsin, it is supposed to sink to the bottom of the pond to overwinter. I don't know how deep the water needs to be for this to work.

2. Pond Maintanence

I don't pretend to know everything about this area of pond building, either. I just try to make as natural a habitat as I can, with the lowest maintenance possible, and then see what happens. I only worry if the pond starts to become smelly, which has not yet been a problem for more than a day or two. One book said that if you can see your hand 5-6" beneath the water, the pond is clean enough.

Here are some things to consider:

Stagnant Water:

Pond pumps are popular because they keep the water from becoming stagnant and smelly. Water flowing from the pump down a waterfall mixes oxygen into the water as it splashes, keeping the water fresh.
Since wildlife ponds don't have pumps, you instead aerate the pond with underwater plants that put oxygen into the water (see above).
Instead of a pump, you could add a water dripper or sprayer, that are sold as accessories for bird baths. The sound of the water dripping will help more wildlife find your pond. A sprayer will be used by birds (including hummers) to take baths. If you make sure the water they use goes back into the pond, they will help aerate some of the water in addition to allowing you to watch more wildlife. They use electricity of course, but I've seen some that come with solar panels.
When you have to add water to your pond (see below), make sure the water from your hose or bucket splashes into the pond, which also adds oxygen.

A Spring algae bloom in our pond.

Dealing with Algae:

Some ponds get algae blooms- when there is so much algae growing in the pond that the water is completely full of it. A balanced pond does not get clogged with algae. The plants and animals and other parts of the ecosystem keep it under control. See the plant section above for more info about this.
Warm water helps algae grow, so the thing that has worked best to control algae in our pond is to keep the majority of the pond's surface area covered with plants. This keeps the Sun from warming the water every day.
Snails and fish and tadpoles eat algae. I tried to buy some snails (they're sold in pet stores for aquariums and online for ponds) when we first built our pond, but no one could tell me if the snails would survive our Winters. It turns out I need not have bothered, though, snails moved into our pond on their own, like magic. Where did they come from?

Algae blooms are normal in a new pond before the system balances itself. This can take a couple months.
Algae blooms are normal each Spring, before the plants have grown back after dying off each Winter.
You can manually remove algae that's floating in the pond. This can be done with a toilet brush, or we use one of those tiny leaf rakes that are about 8" across, that are meant to get between the bushes. The algae you pull out is good fertilizer. However, we learned to stop doing this when I looked at some of the clumps of algae I removed and saw some dragonfly nymphs struggling to get out of it. I put them back into the water.
Bags of barley straw meant to float in your pond are advertised as a natural way to control algae. I tried this, though, and our pond seemed to get worse. Then I noticed that the fine print on barley bag said that it doesn't work in stagnant water and if it's in stagnant water it will start killing the good bacteria in the water. I removed the barley and our pond improved.
Organisms in the soil you've put in the bottom of your pond are supposed to help keep the water clean.

2015 Update:

In 2015, I finally broke down and bought the recommended number of floating plants for the pond. They were $3.95 each at the garden center, and you're supposed to put one per each 2 square foot of surface area in your pond. I figured that I would need 5 or 6. I didn't want to spend that much money on annuals that I had to buy every year, and the plants weren't even labeled at the garden center so I didn't know what I was buying. They looked like seaweed. But it seemed like the pond had been having more algae than it should, so I bought some. When I went to put them in the pond, I realized that each bunch was held together with a rubber band, and actually held lots of strands of whatever they were. So was I supposed to buy 5 bunches for the pond or one bunch that came apart into 5 pieces? I don't know, but I untied them all and left them to float in the water. They cover a lot of the surface, and so far the water has been as clear as it ever has been. I can see tiny tadpoles swimming in the water from the inside the house. This is also the first year that plants were able to survive the winter, so that is also helping to keep the water clear. Maybe I can take some of the "seaweed" out of the pond in the fall and see if I can overwinter it in the house.
By late June, the unnamed floating plants had filled the pond too full, and I started trying to remove some, which was hard to do without removing other life forms from the pond. So I believe I was only supposed to buy one bunch of the floating plants, since it would eventually grow to be big enough.
I also found out that frog tadpoles eat algae when they're young. This if the first year we've had tadpoles, and we have a lot. Between them and the floating plant, we haven't had any algae problems this year- the water has remained crystal clear.

This year, the pond was full of arrowheads, that overwintered for the first time, duckweed that eventually covered the surface, and the unnamed floating seaweed like plant of which we mistakenly put too many in the pond.

Young tadpoles eat algae, helping to keep the pond water clean.

When the Pond Water Gets Low:

One of the reasons I wanted to build a pond was that I was tired of filling the bird bath every day. Unfortunately, the water in a pond evaporates, so if it doesn't rain often, I still have to add water to it. There are things to consider when doing this:

Remember that if you have municipal water, it may have a high chlorine content and you don't want to add a lot of it to your pond at once or it could hurt the plants, animals, and microbes.
The books say that you shouldn't add more than a tenth of the volume of the pond in chlorinated water, or that if you need to add several inches this is too much chlorinated water to add at once. Instead, they recommend only adding a bit of chlorinated water a day, or letting the water sit in buckets for one or two days so that the chlorine evaporates before you add the water to the pond.
This all seems a bit cumbersome to me, so I've just added water with our hose when it's needed it, and so far haven't noticed any problems. I did later discover that you can buy a filter for your outside hose that removes the chlorine (search online for "water filter for garden hose"), and have since been using that when I add water to the pond.
When adding water, don't put the hose under the water. Place the hose so that the water gently splashes onto the surface. The splashing adds oxygen to the water, which helps keep the water aerated and the pond balanced.
You could also add water from a rain barrel, so you don't have to worry about the chlorine content.

Controlling Mosquitoes:

Mosquitoes can only breed in still water. This is one of the big reasons most people want a pump in their backyard pond and why in areas with mosquito spread diseases, such as West Nile Virus, there may be ordinances against having still water ponds. However, in a balanced pond, there will be wildlife that is happy to remove the mosquito larvae by eating them.
In the first few weeks after we built our pond, I noticed hundreds of tiny brown dots suspended in the water in the shallow end. These were mosquito larvae. As they get larger, you can see them hanging upside down from the surface of the water and squirming around. I had read that if you squirt the surface of the water with the hose once or twice a week, it will disrupt the development cycle of the larvae and they will die. I tried this and it seemed to work. We are blessed with very few mosquitoes in our yard (thanks to bats and frequent breezes), so if hundreds of mosquitoes had hatched from our pond, I think we would have noticed.
Shortly after I attempted mosquito control with the hose, I saw a dragonfly laying eggs in our pond. They also only lay eggs in still water. The dragonfly nymphs that hatch from the eggs and live underwater eat mosquito larvae, and I haven't seen any mosquito larvae in the water since (see more about dragonflies in the next section).
When frogs move into your pond, they will also eat mosquitoes (larvae and adults).
Another suggestion I've read is to put minnows, bought from a bait shop, into the pond to eat the larvae. I discussed this with a person from a local bait shop, and he thought that the minnows would not live long in a small, warm pond without running water. And I didn't want them to die over Winter, so I did not try this method.
Another suggestion I read is that caffeine kills mosquito larvae. Put plain powdered coffee in the pond, just enough to change the color of the water slightly. I haven't needed to try this, so don't know if it works, or if it affects other life in the pond.

3. Wildlife and the Pond

Above is a close up of the pebble beach end of our pond. The shallow water and gentle slope lets this frog and other creatures get into and out of the pond. The flat rocks on either side of the water are used by the birds when drinking.

Below you can see one of the logs that I stuck into the deep end of the pond to help creatures access the water. It can also help bugs or small animals get out of the pond if they're stuck. Later I piled more rocks onto the back end of the log to keep it in place.

Below: This rock jutting out into the shallow end is balanced on a wide piece of pvc and some other rocks, so that there is a tunnel underneath it that can shelter animals in the water. Animals above the water sit on the rock and drink. Eventually the rock broke along the crack you can see in this photo, but then the end that fell into the water made a perfect ramp for birds and animals to get to the water and drink.

Allow a moderate amount of dead leaves to accumulate in the pond to be used as breeding & hiding places for amphibians and reptiles.

Build a mound of twigs and leaves outside the pond but near the edge so toads will have a place to burrow into.
Frogs need dense, shady ground vegetation for shelter after they leave the pond- plant sedges, rushes, or grass for this.
Plant night blooming flowers to encourage moths, which will provide food for frogs, such as nicotania or evening primrose.

Building Habitat:
To improve the habitat value of your pond, do as much as you can of the following:

Arrange the rocks in and around your pond to leave nooks, crannies, and tunnels. This will provide shelter, as well as access and escape routes.
Leave places for wildlife to get to the pond. Don't put large rocks around the entire edge of the pond, it makes it too hard for small animals to reach into the water. One book even said that frogs can stick to hot rocks! I designed my pond with two open areas around the edge, one with pea gravel and other other with low growing plants. In a later year we added a third beach when one of our big rocks fell into the pond. The new beach area was used almost immediately by the larger birds.
If you leave muddy areas at the edge of the pond, they will be used by various wildlife. Butterflies gather at sheltered mud puddles (called puddling) to drink the minerals from the mud. Muddy areas also benefit birds and bees (such as robins and mud dauber wasps) that use mud for nest building. In our pond, I didn't have to do anything to create a muddy area. The edges where the water meets the ground stay muddy, although sometimes the mud falls into the pond and I need to add some soil.
Place large sticks or small logs at a couple different spots on the edge of the pond in the deep end. Leave one end of the stick on the beach out of the water and anchor it with rocks. Let the other end trail into the water at a gentle slope. This can help any wildlife that are stuck in the deep end of the pond get themselves out.
Put in some vertical sticks for dragonflies to land on. I put a few bamboo garden stakes into a pot full of dirt that I left in the bottom of the pond (but don't remove in the Winter). Just make sure you don't poke the sticks through your liner. They stick almost straight out of the water, and as you can see below, the dragonflies do use them:

You can add flat rocks just under the water surface for birds to stand on while bathing, or just a pebble covered area works too.
The books say to put a pile of logs and sticks into the deep end to provide places for frogs to hide from the racoons or large birds that might try to eat them. This makes sense, but I couldn't figure out how to do it- the pieces of wood I added just floated, and I didn't want to wedge anything into the mud at the bottom and risk piercing the liner.
On the advice of one of the books I read, I also went to a nearby natural pond on public property and got a gallon of water from it. I added the water to my pond in order to "inoculate" my pond water with whatever normal microscopic organisms there are in ponds.

Wildlife Seen at Our Pond:

Once we finished our pond building at the end of May (2012), wildlife began using it right away:

Birds began using it for drinking and bathing immediately. They also took dust baths around the edge before the plants filled in.
In less than a week there were little beetles living under the water. Where did they come from?
Mud dabber wasps came to take mud. I don't know where their nests are, but they use mud to build tubes in which they lay their eggs.
I saw dragonflies laying eggs in the water. They choose still water and hover over it, dipping the end of their tail into the water repeatedly as they lay eggs.

By July I was amazed that there was a lot more life in the pond water:

There were bigger underwater beetles.
I found a dozen dragonfly shells stuck to the arrowhead and cattails. The eggs turn into dragonfly nymphs that live underwater, then crawl out of the water to break out of their shells, spread their new wings, and fly away. The information I found said it takes 2-3 years for the nymphs to turn into dragonflies, but it only took a couple months in our pond. (See the photos below.)
There were dozens of tiny snails.

By early August I saw a frog! I wasn't expecting them to move in until the following Spring. It was a green frog. The next night I saw it just sitting in the shallow end, probably waiting to catch bugs.

In 2014 we began hearing one peeper frog in the Spring and one or two tree frogs calling during the Summer. These frogs don't live in the pond, but do need to live near water in order to breed. By 2015, we had a much larger chorus of frogs serenading us in the Spring, and we saw tadpoles in the pond for the first time!

Here are photos of some of the wildlife that have used our pond:

Birds are our most frequently seen visitors- for drinking and bathing.

Lady Frog was with us for two seasons, 2012-2013.

Mammals drink from the pond too.

Can you see the underwater frog in this picture?

Here are the tiny tadpoles, which turn into frogs like the tiny one below. We saw tadpoles for the first time in June of 2015 (the 4th summer after after we built the pond), and they grew into frogs by the middle of July.

This is a parent starling (upper right) and a baby starling (lower left), both taking a bath in two of the pond's shallow areas. There were two babies and it was quite fun to watch them figure out how to get into the pond.

Dragonflies!

Above and right you can see empty dragonfly nymph shells clinging to the miniature cattails and arrowhead. Dragonflies spend the first part of their life cycles underwater, when they're called nymphs. While they're in the pond, they will happily eat any mosquito larvae that show up. When they're ready, they climb up out of the water, breaking out of their shells to spread new wings and fly away as dragonflies.

Dragonfly Rescue

In July of 2014, I was fortunate enough to go outside just after a nymph had emerged from its shell, which is shown on the stem of the arrowhead plant to the right. The shell was still green at this point, but will turn brown later. Unfortunately, the dragonfly that emerged had somehow fallen into the pond water. It was fluttering its wings, but was unable to break away from the surface. I lifted it out with our small rake and was able to enjoy seeing it up close for a few minutes (after running in the house shouting for Bear to come see) before it flew away.

4. Winter Maintenance: Keeping the Pond Unfrozen

Our pond is kept unfrozen by a stock tank heater.

In the Winter, I keep part of the pond surface unfrozen so the birds and mammals can still access drinking water. But even if you don't want to do this, you shouldn't let ice completely seal the surface of your pond. It can both damage the pond liner and cause any wildlife hibernating under the water to suffocate, because the gases they exhale can't escape.

I read about several ways to keep the pond from icing over, but I think they must have been written by people in warmer climates that only get a bit of ice on the surface of the pond during a mild Winter:

float something in the pond like a log or a ball
put a twig in the pond and jiggle it every day
set a hot pot of water on the pond every day and let it melt through the ice

In our cold climate (Zone 5, which gets down to -20 degrees F), where all the water in our pond becomes one big chunk of ice, I use an electric heater. The first Winter I used a small bird bath heater that was 200 watts. It worked to keep the shallow end open, but I wasn't sure if there was any way for the gases from the deep end to escape. So the second year I bought a stock tank heater (1500 watts), which is used for keeping large tanks of drinking water for farm animals unfrozen in the Winter. It was strong enough to keep the entire pond unfrozen. However, our electrical bill went up about $50 a month from the tank heater, so I'm not sure what I'll do for the next Winter. Maybe I will try putting the bird bath heater in the deep end of the pond, on the new rock step we built (described in the next section).

2014 Update:

For the Winter of 2014/15 I bought an in-between size- a 300 watt pond de-icer from The Perfect Climate. It said it would work for up to a 300 gallon, pond, which I thought would be much bigger than my pond. It came with a 15 foot cord, which I also thought would be long enough to reach from the outlet against my house to the pond. I was wrong on both counts. 15 feet wasn't anywhere near long enough, and the instructions said to not use it with an extension cord or dire consequences would follow. So Bear asked an electrician he knew if he could extend the cord for us. He said that as long as we use one of the thicker (very expensive) extension cords (15 amp, 125 volt) and that we keep it very, very dry, that it would be safe to use and not burn out the heater. (When I tried to pull apart the extension cord that I used to connect last year's stock tank, I realized that the ends of the two cords had melted together. Not good!)

So I attached the extension cord to the pond heater and wrapped the connections in lots of electrical tape. Then I put the connection into a ziplock bag, which I sealed and wrapped with duct tape. Then I hung this part above the ground (on the shepard's hook below left) so that it would not be laying in melting snow. This seems to work well, but the 300 watts was still not strong enough to keep open anything other than a hole that was about a foot in diameter (below, right). I also needed to have the heater near the surface in order to keep the hole open, so I did put the heater on the new rock step (see Spring Cleaning below) that we built in the deep end of the pond. This would have been easier if I could have gotten the heater to float. It does have a flotation device (some styrofoam) that you can buy to make it float, but I could not find anywhere that sold it. I tried to make my own, but without the right hardware, it did not attach securely enough and kept coming off.

When it got really cold, the 300 watt heater wasn't enough to keep the hole open at all, so I started pouring a bucket of hot water onto the ice every morning when I went outside to feed the birds. Then I hit the ice with a large stick I kept handy, and on most days this broke through to the water. I think this system will work, if I just get a pond heater that has a higher wattage next year.

In the Spring of 2015, I went out and bought more perennial pond plants, ready to try again to get something to overwinter, but when I climbed in the pond to plant them, I realized that some of last year's arrowhead (see above) had survived and was growing! I wonder if this has to do with keeping the deep end of the pond open for the first time over the Winter?

5. Spring Cleaning the Pond

Walking into the pond to perform maintenance or to install plants can be daunting. The pond bottom is slippery and full of rocks, and it's a bit scary wondering what is living down there. This Spring (2014), Bear was the brave one who walked to the deep end to pull up a large rock that had fallen in and remove some of the excess algae by hand:

Bear successfully removed the heavy rock that had fallen off the edge of our pond. Unfortunately, after he did that, it occurred to me that if we rested it on top of the planting pocket/ledge in the pond, it would make a great step. Then we could get into the deep end of the pond without having to walk through all the slippery rocks in the shallow end. So Bear lifted it back into the pond and rested it on the planting pocket at the side of the deep end. We now have a very convenient step and another beach area that allows more wildlife access to the pond.

6. The Pond in Later Years

Year Two: 2013

Year Three: 2014

It's normal to see a lot of algae in the Spring before the plants grow back and help normalize the system.

We had an extremely cold Winter in 2013, and the duckweed was the only plant to survive. This year it covered the entire surface of the deep end of the pond. The arrow head (upper left corner) and water hyacinth I added this year.

Here's a close up that shows the tiny duckweed covering the surface in between the water hyacinth. Both of these plants float along the surface of the pond, with their roots dangling in the water. Duckweed is supposedly edible, but it's so tiny I'm not sure how it could be collected and cleaned for eating. The "weed" part of its name is what it's considered by most people, but I think it looks good. Before these plants grew, the surface was covered in algae instead.

This year the pond is quite overgrown and bursting with life.

Year Four: 2015

This year is looking to be the best yet! As of early June:

We have been serenaded by a great number of frogs each evening (in previous year there's been one or two).
The arrowhead plants managed to survive the Winter and grow back. However, some of them didn't get rooted into the ground correctly and started floating. I pulled them out (photo to the right), then got brave and got into the pond to try to plant them. The pond may not seem very deep, but when I bend over to reach the bottom in the deep end, I almost have to put my face into the water to reach.
I put a lot more floating plants in and the water has stayed algae free so far.
We have tadpoles!

Baby arrowhead.

Spring, 2015. There are a few small arrowheads showing up in the deep end.

July, 2015. The arrowheads grew.

By late Summer, the arrowheads had filled the pond, even into the shallow end, making it look a bit prehistoric. Good thing the tubers are edible.