Waterfall Construction

There are 3 important steps to creating a waterfall.

1.  Use an AquaFall which is a preformed waterfall unit and filter all-in-one.   They are available in small, medium and large.

AquaFalls

2.  Strategically use Black Expandable Foam to seal in the rocks to direct waterflow.

3.  Use the right size of pump.

------------------------------

AquaFalls

In order to create a waterfall, you need to have a basin area at the top of the waterfall.  We find it very convenient to use one of our AquaFalls.  The tubing from the pump connects into either side of the Aquafall and the water flows up through the AquaFall and then out over the fake stone lip.  The AquaFalls needs to be properly installed with it being level from side to side and approx. 1/2 bubble off from front to back on the level.  The back side should be about a 1/2 bubble higher than the front.  This allows for better water flow off the front lip.  It must be level side to side, though or else the waterfall will be crooked.  The ground underneath the AquaFalls should be tampered down very well or else mortared to reduce soil shifting.  If it's not and the soil shifts even just 1/4" , the AquaFalls flow will look differently and it may not be to your liking. 

The fake rock lip comes off the AquaFalls and screws back on with special nuts and bolts that are conveniently made within the AquaFalls.  The pond liner is attached to the AquaFalls by inserting it between the fake rock lip and the black filter unit.  Silicone glue is also used for a better seal.  An awl is used to puncture the liner where each bolt screws in.  Between the silicone and the rubber pond liner acting as a seal, a waterproof seal is made from the pond liner to the AquaFalls.

Depending on the style of your waterfall and if the water drops directly into your pond or if it goes down a little stream and then goes into your pond, the creation of the stream and the placement of the rocks depends on your creativity. 

If your waterfall sits at your pond's edge and flows the water directly into your pond, then you will want to strategically stack whatever rocks you desire up in front of the waterfalls in order to camouflage the liner and the AquaFalls unit.   This is done by putting larger rocks on the bottom and as you build, adding smaller rocks.  If you are super strong or have a few guys or a forklift, you can add larger boulders directly in front of the AquaFalls unit to camouflage it.  Again, the size and the placement of rocks is up to you.  The idea is to camouflage the AquaFalls and the liner.  If you have really heavy boulders you can put a piece of styrofoam underneath them to protect the liner from tearing.  You can get sheets of it at your local home improvement store.  Make sure it doesn't have any fire retardants or anything applied to it.

If your waterfall consists of a waterfall that is away from the pond's edge and has a stream that goes to the pond, then you will use the same strategy of placing rocks in front of the AquaFalls as described above.  You will however, need to create the stream bed.  You can follow some of the instructions for creating a stream on our website in addition to the following information. 

When you create your stream that goes downhill to your pond, you will want to dig the stream bed out slightly, depending on the thickness of your rocks you will choose.  Due to splashing from the waterfall, your side banks will need to be about 8" high, depending on how powerful the water flow will be.  This can easily be achieved by placing an 8" diameter rock along the side walls followed by smaller, 3-4" rocks (like river rocks or cobblestones) and perhaps pea gravel, within the stream bed. 

You will most likely want to create little "mini" waterfalls throughout your stream. This is done by digging out the stream bed "stair-like" areas.  You will want these areas to be wide enough and deep enough to hold a nice piece of flat rock like ledge rock or flagstone.  (Don't get any limestone as that is toxic to fish and causes high algae blooms).  You also want this piece of rock to be as flat as possible to create a nice, even flow of water that will go over it.  So, you can create as many "steps" as you want in your stream bed going down your hill.  Adding a little curve makes extra interest instead of a straight stream bed.   Also, placing a large rock in the middle of the stream bed causes more interest in water movement as the water would then have to divert around the sides of the rock.   When you make any curves to your stream, think of this:  Usually when the stream goes to the left, there is something large on the right side of the stream that is causing the water to turn to the left.  The same goes for the stream that would turn to the right.  There would be something large on the left that would cause the stream to to turn the right.  So, when you make these boulder placement decisions, think of what would cause the water to turn a certain way and then put boulders in the stream accordingly.  The larger boulder would be placed just before the water would flow in the different direction, like as if it were in its way.  That is a good clue to making a professional looking stream and waterfall.

The pond liner from the stream should overlap into your pond.  You don't have to adhere it to the other pond liner but you can if you want to.  We recommend our 2-sided Quickseam tape found here. 

Black Expandable Foam

Black expandable foam is used to seal in the large, flat rocks that form various waterfalls.  It is not meant to seal in every rock in the waterfall or stream, just the ones that create the waterfall itself.  After the waterfall within your stream bed is level and you have placed your liner over it, you can spray on the black expandable foam.  Carefully put the large, flat rock such as flagstone in place where you're making the mini waterfall, and make sure it's level again, carefully adjusting it if it is not.  Next, "sprinkle" pea gravel or cobblestones (3-4" in diameter) around the edges of the flagstone as you will see it erupting out from the corners of the flagstone.  The pea gravel will sink into the expandable foam to make it look more natural.  If you don't want to add pea gravel, you can wait till the expandable foam dries completely  (in about 12-24 hours) and can cut it away with an X-Acto knife or something sharp.  The expandable foam only needs to be applied underneath the stone and in front of it.  Front, being in the direction of the waterflow. 

You will also want to put a couple of larger rocks on the sides of the flagstone waterfall in order to force the water to flow through the area over the flagstone.  You can seal in these rocks with the expandable foam as well.   (Sketch drawing 101 ! Ha!)

Waterfall.  Grey is the flagstone, black is the liner, aqua is the rocks and the green is the black expandable foam.  This is a waterfall design where you will see water moving across the rocks going down the stream bed as the water is flowing down. Note:  the vertical rocks protrude out from the waterflow going down.  This is what causes the splash and more "white water".

On this waterfall design, the water is flowing straight down instead of on an angle like the sketch above.  You will not see water splashing around on the rocks as much, but you will see a longer and deeper water flow pattern going across the flagstone waterfall lip. Note, the vertical rocks are placed behind the water flow and underneath the flagstone lip.  This is so they won't disturb the clean water flow flowing off of the flagstone waterfall lip.

If you want a longer distance between waterfall drops, you would place the rocks something like this sketch above.  Only a little black expandable foam is used but you will have to have everything level and in place first and the expandable foam can will self-seal in about 5-10 minutes after it's last use.  By placing the flagstone hanging out farther into the stream and beyond the vertical rocks,  it creates a more of an "echo" sound from the waterfall which results in a louder waterfall sound.   This is shown above with the white area underneath the flagstone lip.  The further out the lip, the more sound but be careful that enough of the flagstone still sits on a flat surface to support the weight of the lip.

This is supposed to be an aerial view of the waterfall.  The grey is the flagstone, the aqua color is the larger boulders to place on the sides of the flagstone, the lavender is the water and the green is the expandable foam.  Seal under the flagstone with the expandable foam and on the sides of it where the larger boulders would be placed. This forces the water to go through the waterfall area instead of underneath the flagstone or behind the boulders.  Remember, the expandable foam can be hidden with pea gravel or cut after it's dried.  It will seal to the rocks and to the pond liner and yes, to your hands or anything else.  We recommend wearing some rubber gloves or else you will have black hands for about a week.  (Gasoline does not take it off!)

Choose the Right Pump

Create a waterfall with the wrong size of pump and either you'll have Niagara Falls in a small area or barely a trickle in a larger area. Choosing the right size of pump is important for creating a waterfall.  There is a bit of math involved and it's important that you follow these instructions.

First of all, if it's just a waterfall that you want a pump for and NOT for providing proper aeration of your pond, then the formula is simple.  For every inch wide the weir is (that's a fancy word for the waterfall lip's width) then you multiply 100 GPH (gallons per hour) for a gentle stream affect.  If you want more of a "white water" affect, then you calculate 200 GPH for every inch wide the weir is.  So, if your top waterfall weir is 48" across, then you would need a pump that pumps 4800 GPH for a gentle flow or 9600 GPH for a more "white water" flow.   BUT, BUT, BUT that is not all.  It's important that you don't stop there and run to our website and buy that size of pump.  You also need to take in consideration the vertical height the pump will be pumping water and the horizontal distance it will be pumping water.

Figure out where the pump will be located from the waterfall.  For optimal water circulation, the pump should be on the OPPOSITE side of the pond as the waterfall.  So, if your waterfall is at 3:00 then your pump should be at 9:00 on the face of a clock.  Measure this horizontal distance where the pump will be at and where the top of the waterfall will be at.  You will need this information to calculate the "lifts" of the pump.  For every 10 feet of horizontal distance you add 1 foot of lift to the pump.  So, if you need to pump the water 25' horizontal distance you would add 2 1/2 feet of lift to the pump.  BUT, you also must calculate in the VERTICAL distance the pump has to push water too, to figure out the lifts.

Now, measure from the TOP of the pond's water surface to the top of the waterfall.  This is the vertical distance refered to as part of the "lift" of the pump.  It is also refered to as the "head" of the pump.  For every 1 foot high the vertical distance is, it is 1 foot of lift.  For example, if your waterfall is 6' high from the top of the water's surface, then that would be a 6' lift.

Next, you must add the two "lifts" together.  Add the horizontal "lifts" and the vertical "lifts" to get your total "lifts".  In this case, we would have a horizontal distance of 25' which is equal to 2 1/2' lift and a height of 6' for an additional 6' lift.  The total lift would be 8 1/2'.  Given the formula above for the WIDTH of the weir, you could choose a pump that pumps 4800 GPH for a gentle stream or a 9600 GPH for a heavier stream.   The lifts then are added to the pump description.  This is VITAL to remember or else you will get the wrong size of pump.  You would then need a pump that pumps 4800 GPH @ 8 1/2' lift or a pump that pumps 9600 @ a 8 1/2' lift.  It's is vital, vital, vital to remember the lifts.  What this means is that for the gentle stream, you want a pump that pumps 4800 GPH at a 8 1/2' lift.  You don't want a pump that pumps 4800 GPH at a 2' lift or a 30' lift, but at an 8 1/2' lift.  ALL the pumps on our website and anywhere you buy pumps, the GPH of the pump listed is either at 0' or 1' of lift.  You will need to look at a chart from the manufacturer or on our website, that will tell you the performance of the pump at a certain lift.  Again, this is vital, vital, vital information.  That 4800 GPH pump may be labeled as a 6200 GPH or something like that because the 6200 GPH pump is at a 0' or 1' lift.  As with anything working against gravity, it takes more energy to push water (or anything) up hill so as you go higher up and further against gravity, the less the water pressure will be. That is why it is so important to remember the "lifts" of the pump because your waterfall will require a certain amount of pressure in order for it to have the look that you want it to.

(Shown above:  AquaFalls waterfall and filter unit at the top right, 11:00.   Skimmer with pump inside at 3:00.  Pump tubing goes around pond's edge and attaches to the side of the AquaFalls.  The length of tubing is the horizontal distance.  The height from the top of the water's surface to the top of the Aquafalls is the vertical distance.  Even if your pump was in the pond instead of in the skimmer, the vertical distance would still start from the top of the pond's water surface.   The tubing can be buried so it's not visible and  the entire AquaFalls unit can be buried so it is camouflaged as well.)

Now, IF you have a pond AND a waterfall and you want to have only one pump, there is some other information you need to know.  It's not as hard as the above, so don't fret. 

In order to have proper water circulation in your pond, you need to circulate half the volume of water in your pond every hour through your waterfall (or yes, a fountain but that is something different right now).  If your water flow required for your waterfall EXCEEDS what is required for optimal water circulation, then you will have a large enough pump for both your pond and your waterfall.  If the pump for your waterfall is too small, then you will need additional aeration from another source such as a fountain or aerator.

To figure out the volume of water in your pond in gallons (since we are always dealing with gallons per hour or GPH), you use the following equation:  Length x Width x Average Depth x 7.5 = Total Volume in Gallons.  So, say your pond is 8' x 12' x 3' deep.  You multiply 6' x 8' x 2' x 7.5 and you get 2160 gallons.  That is the volume of water in your pond.  Now, going with the above example regarding the pump and you choose either to have a 4800 GPH pump at a 8 1/2' lift or a 9600 GPH pump at a 8 1/2' lift, you now have to decide if the pump that you need for the waterfall is large enough to provide proper aeration for the total pond, too.  The pond holds 2160 gallons and as I mentioned above that you have to circulate 1/2 the pond's total volume of water every hour for optimal circulation.  So, half of 2160 is 1080 gallons.  So, we would need to circulate at least 1080 GPH for optimal circulation for this size of pond.   Since our pump would be at least 4800 GPH or 9600 GPH @ 8 1/2' lift, then our pump is plenty big enough to provide enough pressure for the waterfall AND for the optimal circulation of the pond. 

Let's say, for example, that we decided to have a much smaller waterfall, like 8" wide.  We would then need a 800 GPH pump at a 8 1/2' lift.    We need to circulate at least 1080 GPH every hour for optimal circulation for this size of pond.  So, we would either need to get 1080 GPH pump and divert the extra 280 GPH to something other than the waterfall which required only 800 GPH or to something else like a fountain or filter, or for it go to directly into the pond.  We could choose to buy just a 800 GPH pump @ 8 1/2' lift but we would need to also purchase something else that would add extra aeration to the pond like an aerator.  

So, as you can see there are many variables on how to set up a pump and waterfall system.  The key thing to remember is the "lifts" of the pump.   Don't be concerned if after you have figured everything out that it sounds like your pump is too "powerful".  If you've measured the horizontal distance and the vertical distance, multiplied the inches of the weir times 100 for a gentle stream or 200 for a heavier stream, and have calculated the lifts correctly, then that is the size of pump you will need.  Period.  In the above example where we would need at least a 4800 GPH or 9600 GPH @ 8 1/2' lift pump for a pond that was only 2160 gallons, that would still be fine.  It's the WATERFALL that is requiring so much water pressure in order to have the look that you want.  Many people get worried thinking they are having "overkill" with their pump or that it just sounds like too big of a pump to have.  That is not the case, not if you want that large of a waterfall.  And if you gave it some thought and decided on what size of waterfall that you want with your pond and that will look good into your landscape, then that is what you go by. 

For those of you who have a very large pond or live on a lake and want to create a waterfall in your yard going into the larger body of water, all you would need to do is measure the horizontal distance, the vertical distance and figure out the GPH based on the weir size (100 GPH for every inch wide the weir is for a gentle stream and 200 GPH for every inch wide the weir is for a heavier stream).  Since the body of water would be too large (like over a million gallons or so), then all you need to calculate is the pump size you need just for the waterfall, not for creating optimal water circulation too since there's just too much water to do that.

I hope this helps.  It may be best to go over and re-read the information above until you understand it thoroughly.

You may cross-reference information in our Ponds 301 in our Ponds Online Course where it discusses choosing a right pump and filter for a pond.