Once you have begun excavating, you will need to make sure that the edges of the pond are level. Unless the building area is basically flat, don't try to eyeball it. Depending on the terrain, a difference in level when you fill the pond can mean lots of extra work. We recommend using a line level or a water level to get the height of the edges right.

Using a line level: hammer a stake into an edge that is at the desired level. Run your string from that level point to stakes at various points around the edge of the pond. Using the line level, mark on these stakes the level, and use them as a guide as you dig. You will make the final adjustments to the level when you fill the pond with water and do the edging.

Making a water level: a water level is a clear plastic tube of the same variety that you use for your pump. To create a water level, buy a 10 to 30 foot piece of 1/4 to 1/2 inch clear flexible tubing (depending on the size of your pond). Attach one end of it to a wooden stake using duct tape. You will tape down the last twelve inches of the tubing to the stake, making sure that there is at least a 6 inch "window" in that 12 inches that is not taped over, so you can see the water level. Draw a line next to the tube on the stake: this will be your level. Hammer the stake into the ground so that the mark you drew on the stake is at the exact point where you want the level of the water to be. Fill the tube with water. As long as the the water in the tube is equal to the line you drew on the stake, the point at which you're standing with the other end of the tube is at the same level.

Many pond owners are choosing to use an underlining when they line their ponds. This can only extend the life of your pond. The 45 mil gauge EPDM liner that we recommend is extremely tough, so if your soil is too not rocky you can probably get away without an underlining. However, if your soil is rocky, or if you have chosen to use a thinner gauge liner, we strongly recommend an underlining. The two biggest causes of holes in liners are 1) you and 2) dogs. If you drop a heavy, sharp edging stone in the pond it can puncture the liner, and without a fence, stray dogs may come to wade in your pond on hot summer days.

The three most common types of underlining are sand, foam carpet underlining, and geotextile underlining. The last two are the most effective. If you have old carpet underlayment lying around, by all means use it. But if you have to go out and buy carpet underlayment you will find that geotextile underliner is much less expensive, and more durable to boot.

The number of gallons per hour at DISCHARGE POINT, should not exceed the number of gallons in your pond (unless you want to turn your pond into a brook). Volume at discharge point varies with the type of pump that you purchase, and will vary as your pump ages. If you will be attaching your pump to a filter, fountain or piece of statuary, the attachment will usually specify the gallons per hour required.

We recommend placing the pump some distance from the discharge point to get the most thorough circulation of water. Horizontal distance accounts for a very small loss of volume at the discharge point, so this will not greatly effect your flow.

One final and very important note: always use a ground fault interruptor when installing your pump. A ground fault interruptor is a device built into your plug that will automatically cut power to the pump if it detects an electrical leak. GFIs are required in bathroom outlets to prevent electrocution by dropping devices into the tub or sink.

We recommend having a professional, licensed and insured electrician install one in the outlet you intend to use to plug in your pump. It is possible to buy extension cords with GFIs built in, and they are better than nothing, but they are NOT as durable and fool-proof as one installed by a professional.

When a member of our staff was working as a contractor building ponds, he made sure to have a licensed insured electrician do all of his wiring. One day his client, while standing knee-deep in her new pond pruning her iris, cut right through the cord of her pump leaving the copper wires exposed in the water. The GFI cut the power instantly and may have saved her life. With animals, kids and yourself all enjoying the pond, there are many reasons for a pump to leak electricity, and as many reasons to make sure you and yours are protected.

The formal edge is much more involved. Larger, deeper and more elaborate formal features will usually need to be poured in order to support the weight of the masonry edging where people may stand or walk, and to resist the elements. For the mostly smaller formal water gardens, which often do not require great depth, we have developed a durable and simple method of construction using cinderblocks, gravel, Sakrete, and a pond liner.

Begin by excavating a square or rectangular area with vertical sides, leaving 15 inches of extra space around the perimeter. In this area you will build the foundation for your edging. Step 1 of the foundation process is to dig a trench 3 inches deep and 12 inches wide, 8 inches out from the wall of the pit. The trench will overlap with the edge of the pond. Pack down the soil in and around the trench as firmly as possible. Fill the trench with medium-sized pea-stone and again pack the stones down firmly.

It is vital that this foundation be as close to level as possible. small mistakes underground will look very obvious when you edge the pond and fill it. Once the foundation is level, lay the cinderblocks, hollow sides up, on top of the gravel, and make them flush with where you want the edge of the pond to be. There should be 1 to 3 inches of gravel showing on either side of the cinderblocks. Stack the cinderblocks not more than 3 high and fill them with Sakrete. While the Sakrete is drying, you may fill in the area behind the cinderblocks with the same medium-sized pea-stone.

Now that you have laid the foundation for your edging, you are ready to line the pond. Pull the excess liner over and behind the tops of the cinderblocks and secure it. The final step in completing your formal pond is to edge it with whatever pavingstone is appropriate. Lighter materials, such as bricks or thin slate, will require mortar to be held in place. Thick, heavy slabs of bluestone or other material may not require mortar. Make sure that whatever material you use, it extends 2 to 3 inches over the surface of the water to hide the liner.

Once the foundation is level, lay the cinderblocks, hollow sides up, on top of the gravel, and make them flush with where you want the edge of the pond to be. There should be 1 to 3 inches of gravel showing on either side of the cinderblocks. Stack the cinderblocks not more than 3 high and fill them with Sakrete. While the Sakrete is drying, you may fill in the area behind the cinderblocks with the same medium-sized pea-stone.