
Page 2 -- Continued
Dig
It, Man...
Begin by marking the area where the pond will go. A can of spray paint is great for this. Before determining the dimensions of the finished pond check out our money-saving tip under Component 1 - The Liner. Know where the gas, cable, water lines and other utilities are before digging to avoid any disasters. Do yourself a favor - rent a backhoe if the pond is bigger than a couple of hundred gallons. Scoop out the middle with the backhoe and as far down to the desired depth without digging too deep. The rest must be done by hand and shovel. Prepare the ground by smoothing and tampering any loose soil. Remove any rocks or roots that may eventually puncture the liner.
Its important to have the sides of the hole level all the way around or the water level will tell on you once the pond is finished. The edge of the pond should have a slight rise to keep out rain run-off.
Sculpting the Shelves
The Plumbing
The first thing to decide is what size and type of plumbing to use. We suggest 1 1/2 for ponds up to 1500 gallons then graduate to 2 for ponds over 1500 gallons. 3 and 4 must be considered for ponds over 2500 gallons. Whenever possible use PVC. Its cheaper than flex hose and easy to install. PVC flex hose can be used whenever you must twist around objects. You can use both by installing adaptors whenever you change from one to the other. When installing PVC use PVC glue to attach the PVC pipe to the bottom drain, to attach elbows where needed, etc. The glue needs 24 hours to set.
Most all the plumbing will be hidden under the liner and buried in trenches. Obviously all plumbing that the liner will cover must be installed before the liner is laid.
Component 1 - The Liner
See
Component Schematic
You simply cannot build a good pond without a good liner because it is the skin of the pond and one of the most important components of The Docs Dream System. The object is for the liner to last 20 years.
Run as fast as you can away from preformed ponds. We suggest and use exclusively 45 mil EPDM liner material. We stock widths of 5 1/2, 10, 15, 20, 25, and 30 feet. Larger sizes are available for special order. Liner material is priced by the square foot and is cut from any of these widths to the length you request. Find more information about liners by reading our article Liner vs Liner in the Water Garden Edition of
Whats Up, Doc?.
Heres how to get the correct measurement for liner:
Drop a piece of string 18 from the edge of the pond where the water will crest. Drop the string along the hole at the widest part, allowing it to follow the curves of the hole then mark the string 18 from the opposite edge. Now measure your string. Do this also for the length of your pond.
If the hole that has been dug has any rocks, pebbles or roots in it and is not as smooth as a babys behind a pre-liner or underlayment must be installed to protect the liner. Commercial underlayment is available. We do not suggest sand. It shifts underfoot and can render plant shelves useless. Old carpet can also be used. Roll out the underlayment and cut out holes where the bottom drain and other components are to be installed into the liner.
The bottom drain, skimmer, induction jets and plumbing must be installed before the liner can be laid. When it is time to lay the liner lay it smoothly. Wrinkles should be pulled out, corners folded and neat. Even as the pond is being filled with water the liner should be continually adjusted. Sharp objects have no place in this part of the installation. Keep dogs away and go barefoot if possible.
Component 2
The Bottom
Drain
See
Component Schematic
A Bottom Drain in a pond system does not mean simply a device to drain the pond of all water. It is the way to pull the water from the floor of the pond and re-circulate it through the outside pump and filter system before returning it to the pond.
There are 4 main types of bottom drains.
2 Bottom Drain
This white PVC drain is fit with a 2 opening to the pump. The bottom part
must be plugged for our purposes. It comes with a regular grated white plastic
cover and an anti-vortex cover. The regular cover is great for a water garden
that has no fish. If the pond is to hold fish, especially small ones, the
anti-vortex cover is the best to use because it doesnt suck fish up to the
grating. The drawback to this drain is that it doesnt allow leaves and debris
to pass through to the leaf catcher of the pump making it necessary to scoop the
bottom drain occasionally with a net to get the fallen debris.
3
Bottom Drain
This black domed bottom drain has a 3 opening to the pump. It should not be
used if there are fish smaller than 7 in the pond. The dome sits about an
inch over the floor of the pond and will literally suck small fish into the
plumbing system. The good thing about this bottom drain is that it sucks up
large leaves and debris and brings it up to the leaf catcher of the pump making
it unnecessary to scoop off the bottom trash.
4 Bottom Drain
The 4 bottom drain is similar in design to the 3 and is used on very large
ponds.
Inverted Bottom Drain
This is not a true bottom drain because it is not installed directly into the
liner. It is more of a caged box that is attached to flex hose and allows water
to be sucked from the bottom of a pond. This is an excellent choice for those
who are converting an existing pond to a cleaner system.
Bottom Drain Installation Tips
Component 2a - Check Valve
The check valve assumes a very important role. Whenever the outside pump is installed above the water level of the pond unless a check valve is installed every time the system is shut down the pump will lose its prime. The check valve prevents the water in the plumbing from flowing back into the pond. Its very important that the check valve is installed in the right direction otherwise it will prevent the flow of water into the pump!
Once the liner is down the top piece of the bottom drain is installed. Two gaskets are included with the 2, 3 and 4 bottom drain kits. One gasket goes between the bottom piece of the drain and the liner. The other gasket goes between the liner and the top piece of the bottom drain. Using your fingertips you would feel through the liner for screw holes and attach the two pieces together with the liner in between. A hole is cut out of the center of the bottom drain after this is accomplished. The only thing left to do is place the cover of the drain on the 2 bottom drain or the domed lid on the 3 with screws provided in the kit. Note: The dome on the 3 bottom drain should be filled with sand to prevent it from floating.
Component 3 -
Eduction Jets
See
Component Schematic
These horn-looking devices screw into bulk head fittings that are installed into the side walls of the pond to direct the water and increase circulation. The bulk head fittings that hold the jets should be placed about midway down the wall. We suggest reducing the PVC size to 1 1/2 from the main return line to the induction jets. To create the same water flow in both jets the reduced PVC should tee as shown below.
Although the main purpose of installing induction jets is to add circulation and direct water flow there are several added benefits. Fish simply love to play in the stream. This type of playing gives them great exercise and, in the long term, your fish will benefit with stronger bodies.

Component 3a - Gate Valve
For control of how much water to go through the induction jets a gate valve should be installed. Place it on the reduced 1 1/2 PVC before you tee to each induction jet.
Component 4 -
Skimmer
See
Component Schematic
Skimmers are used to continuously pull leaves and other floating debris off the top of the water. The old fashioned way of keeping the water clear is by using a net to rake off the leaves. During Fall a skimmer is a God-send if the pond is located where trees shed their leaves.
We only keep a fish-safe kind of skimmer in stock. There are others that pull water from the side of the pond thus the name side skimmer that use the same principles as swimming pool skimmers. The danger with the side skimmer is that food being sucked into the skimmer may lure an unsuspecting fish into the device, trapping and killing him.
The skimmer we suggest be used on any pond system that may house fish is one that is a rounded unit with a basket inside that floats to accommodate varying water levels. This unit is installed using 1 1/2 PVC through a bulk-head fitting in the side of the pond wall. It pulls water from all sides and prohibits fish from going past the basket. Like the bottom drain the skimmer should also be installed at an area away from the water return so the waters current can direct the leaves and debris to it.
Component 4a - Gate Valve
If we dont turn off the skimmer whenever we feed our fish the food will literally go down the drain before the fish have a chance to eat. (Unless the fishs name is Daniel. The Doc and I watched with amusement as one of Gaye & Frank Comtois koi, Daniel, learned to tip the skimmer basket to retrieve any food that got passed him). A quick and easy fix to this is to install a gate valve that we can close whenever we want to turn off the flow from the skimmer. This gate valve should be installed in conjunction with a T which should be located just prior to the pump in the PVC line.
Component 5 -
The Pump
See
Component Schematic
The pump is one of those necessary components. The decision that needs to be made is what kind and strength of pump to purchase. Our dream system calls for an outside pump. There are a slew of different outside pumps from which to choose.
The power of available outside pumps range from 1/4 hp to 3 hp (and beyond) and can come in low amperage, high performance and dual speed models. Some models are better suited for high waterfalls than others. Different pumps offer different flow rates (gph). Some people prefer rushing waterfalls while others prefer a gentle stream. Ponds may be built with attached streambeds that run 30-40 feet away from the pond and may rise as high as 15 to 20 feet above water level. All of these factors must be considered when determining which pump is best suited for each individual pond design. Its best to allow The Doc to help you choose the right one for you since the pump is a major cost factor and one of the most important design elements of the project.
It is best to prepare a level, solid surface for the pump to sit. 2-speed pumps allow you to use less energy whenever youre not enjoying the pond. You have the choice to switch it to high when you backwash the filter or if you want the waterfall to really bounce while entertaining.
Locate the pump as close to the bottom drain that feeds it as possible. The less the pump has to work to suck the water the better. Its easier for the pump to push the water. A flooded suction model can be used if the pump is located below the level of the water, for example, on land that slopes below the pond.

From The
Pond Construction Edition of What's Up, Doc?, September 2000
© Copyright 2000, The Pond Doc's Water Garden Center. All rights
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