How to Build a Waterfall (with Pictures)

2024 Author: Samantha Chapman | [email protected]. Last modified: 2023-12-17 09:13

A waterfall is a perfect detail in a garden. The seductive and calming sound of the water hitting the rocks attenuates traffic noises and creates a serene and relaxed atmosphere. For DIY enthusiasts who love serious projects, here's how to build a waterfall while having fun.

Steps

Part 1 of 4: Planning

Step 1. Choose the location

You can install a waterfall along a natural slope or mound, or you can create a slope yourself artificially. Alternatively, if the ground is too hard to dig, consider building a stream above the ground using a combination of stones and rocks as a backdrop.

What is the necessary slope? At a minimum you need 5 cm of elevation gain every 3 linear meters of stream. Obviously, the greater the inclination, the faster the flow of water will be, with a louder sounding waterfall

Step 2. Consider installing the waterfall near an electricity access

If you want a collection basin in the lower part of the stream that brings the water back to the beginning of the waterfall, you will need an electrical connection, to avoid unsightly extensions that run through the garden.

Step 3. Plan the size of the stream

Knowing how much water will flow down the waterfall helps you determine how large the upper and lower basins should be. You certainly don't want to end up with a flooded garden when you turn off the pump. Here's how to proceed:

• First, estimate how much water flows in one linear meter of the stream. If this is relatively small, say about 60-90cm wide and 5-7.5cm deep, estimate about 60 liters of water per linear meter. Recalculate this flow based on the width and depth of your stream.
• Next, you need to calculate the total capacity of the stream. Measure the linear meters of the entire stream. Make sure that both the catchment basin and the one upstream of the waterfall are much larger than the flow of water that flows into the stream. So, if the stream capacity is 378 liters, a 190-liter catchment basin and a 757-liter upstream basin should be more than enough.

Step 4. Get the stones, gravel and boulders

Generally speaking, the waterfalls are built with stones of three different sizes: the boulders or boulders that frame the waterfall, the stones (of medium size) that act as an element of continuity and the gravel that fills the cracks in the seabed.

• Check with a building materials wholesaler or quarry to figure out what kind of stones and rocks you prefer in your waterfall. This way you can get a clear idea of what you want instead of ordering a kit online in the hope that it will then go well with the rest of your garden.

• Here's what you should order to build the waterfall:

  • 1.5-2 tons of large boulders (30-60 cm) for the upstream and downstream basins plus 2-6 tons more for every 3 m of stream.
  • 0.75 tons of medium stones (15-60 cm) for every 3 m of stream.
  • 0.5 tons of gravel (1.5-5 cm) for every 3 m of stream plus another 1-2 tons for the downstream and upstream basin.

  Part 2 of 4: Prepare the Foundation

  

  Step 1. Prepare any necessary excavation by outlining the area of the waterfall with spray paint and informing yourself on the layout of the utility systems

  Mark the course of the stream with paint, it will be of great help when you have to dig. Call the technical office of your municipality or the body in charge and ask to know the route of the sewage / gas / electricity / water systems to avoid causing damage.

  

  Step 2. Begin digging the foundation if necessary

  Dig any area of the stream that needs to be below ground level. Next, make a hole wide enough to accommodate the catch basin, making sure you have enough room for the surrounding stones and rocks. Finally, place the boulders and medium-large stones to define the edges of the stream.

  

  Step 3. Measure and cut out the waterproof mat and rubber liner accordingly

  Start with the mat and finish with the upholstery. Stretch both along the entire course of the stream, inside the basin downstream and in the intermediate pond (if provided). Place some rocks on the plastic membrane to hold it in place or use plastic polymer panels to save time.

  When you lay the waterproofing coating and mat, remember to leave them a little loose at the bottom of each waterfall. If you place rocks or boulders in these areas you tend to cause tension to the coating which could tear

  

  Step 4. Install the downstream catchment basin

  Drill holes in the containment tank (if not already present, see the instructions below). Place the basin in the hole you dug at the base of the waterfall, on top of the waterproofing mat and liner. Insert the pump, connect it to the water system and make sure that the pipe reaches the upstream basin. Now that the sump is installed, secure it with several layers of small to medium rocks (not gravel) and close the lid.

  • Some collection tanks are sold already perforated, but not all. If you have to do it yourself, know that it is not a complicated job. Start at the bottom and drill a hole on the side with a 5cm drill bit. Moving along the side, make a hole every 10 cm. After covering the entire circumference, continue for a second lap.
  • When the lower third of the sump has been pierced, switch to a 2.5 cm drill and do the same for the middle third; finally replace the drill bit with a 9 mm one and drill the upper third.

  Part 3 of 4: Building the Waterfall

  

  Step 1. Work from bottom to top and place the largest boulders first

  Always start from the downstream positions and then go upstream of the waterfall when you set the stones. It is best to install the larger rocks first to define the edges and contrasts. Fill in the bare ground behind each boulder as you see fit, paying particular attention to boulders that are perched in elevated points.

  Placing a large and characteristic boulder behind the start of the waterfall is a great way to give dimension to the waterfall itself. You can also consider putting these elements on the sides

  

  Step 2. Try to place the larger stones as close to the waterfall as possible

  In real streams, small stones and pebbles are swept away by the current. This is why large stones are more natural if they are located near the waterfall. Make a good combination of stones of different sizes to give the composition as natural as possible, otherwise it will look too artificial.

  

  Step 3. Occasionally take a step back to evaluate the composition from a different angle

  In this way you have a very clear idea of what the final work will look like. By working at close range you are unable to understand perspective and a step back can help you. So, with some frequency, stop and walk away to understand what effect the various stones have. It may take up to 4-5 changes for each boulder before you are satisfied.

  

  Step 4. Place the spillway stones accurately

  Slate is excellent for this purpose. Don't be afraid to use even small stones and even pebbles to create the base of the spillway. Here are some things you need to remember as you work on this stage:

  • If you have a hard time holding the spillway stones in place, you can put larger rocks on the top layer as you proceed to build the base.
  • Always check the slope of the spillway with a spirit level. This is an important detail for two reasons. First of all, since you work from the valley to the mountain, you must be sure that the spillway is leveled or tilted inwards; if it is tilted forward, the water will not flow pleasantly. Secondly, considering the horizontal direction, the spillway must be "level" to allow a constant and uniform flow of water without lateral stagnation.
  • Some small cobblestones or rocks protruding from behind the spillway give a little movement to an otherwise too uniform waterfall.

  Part 4 of 4: Assembling the Structure

  

  Step 1. Use mortar to stabilize large boulders

  If you have decided to use particularly large stones for a large waterfall, don't be afraid to use mortar to fix the composition. In this way you stabilize the structure and you are sure that no stone will fall if the ground gives way a little.

  

  Step 2. Fit the smaller stones and gravel under the sides and under the spillway to prevent water from seeping

  In addition, this gives the waterfall a more natural appearance while also hiding the unsightly edges of the waterproofing coating.

  

  Step 3. Fill each gap with a special black foam

  Foaming sealants work best on cold, wet surfaces of rocks. Then, if necessary, vaporize the stream first and then spray the sealant. Start with a little foam at a time, as it expands more than you think. Once applied, know that it will be very difficult to remove.

  • You can also use other types of foaming sealants but be aware that non-stream sealants contain toxic chemicals that are harmful to the fish that will inhabit your pond. Stick to material specifically designed for ponds if you plan to populate your waterfall.
  • Wait 30 minutes for the foam to dry completely (preferably an hour). If you work precisely and accurately, you can apply the foam and start the waterfall on the same day.
  • Consider sprinkling the drying foam with natural colored gravel or sediment. This allows you to disguise it with the rest of the environment.
  • When you spray the foam, wear gloves and work clothes that you don't mind getting dirty. If the foam accidentally lands on a boulder, wait for it to dry and then scrape it off.

  

  Step 4. Install a biological filter tank in case you want to populate the pond with fish (optional)

  If you decide to keep Koi carp, this is the right time to insert the bacteria that will ensure the health and life of your animals.

  

  Step 5. Lay the gravel carefully on the bottom of the pond and along the edges where the waterproofing coating is visible

  

  Step 6. Open the garden hose and spray the entire stream area until the downstream pond is completely filled

  

  Step 7. Start the pump and check that the water flows correctly

  When you see that it begins to flow transparent, move the pump towards the beginning of the waterfall and close the garden hose. Try to camouflage the pump by covering it with gravel or foliage.

  

  Step 8. Check if the water flow is correct

  The waterfall should come into action without the help of the garden hose. Check that the level of the waterproofing coating is always adequate in all points of the stream and that the splashes are contained by the side rocks.

  

  Step 9. Finish the job by cutting off any excess edges of the liner

  Add aquatic or semi-aquatic plants to the pond and consider adding fish. If you really want to make the pond look glamorous, consider installing underwater or outdoor lights to illuminate the area.