Pond Installation

INSTALLING A FLEXIBLE POND LINER

BASIC TOOL LIST

  • Marking Device(s) to outline perimeter prior to excavation. Items such as a section of rope, an extension cord, or garden hose to create informal shapes. Use string and stakes to form straight lines and angles if desired.
  • Tape Measure to check and confirm measurements as outline and excavation are formed.
  • Flat Spade also known as a "transplanting spade"; works great to finalize the outline, remove sod and carve out the pond (excavation) walls.
  • Pick Axe for breaking up hard soil.
  • Round Shovel for digging and removing loose soil from the excavation.
  • Saw or Heavy Pruners to cut tree roots from the excavation walls or bottom.
  • Wheelbarrow to transport removed soil, tools, etc.
  • Garden Rake to smooth sand in the excavation bottom.
  • Straight 2x4 Board to help check the level of the excavation perimeter.
  • Carpenter's Level to place on the board for level confirmation.
  • Builder's or Site Level and Rod (optional) eliminate the need for board, carpenter level, and much of the tape measure use.
  • Backhoe can be used to "rough out" center of excavation, thus eliminating much of the hand work. Accessibility must be considered when using large equipment.

    SITE PREPARATION

    Define and/or clear potential hazards such as underground utility, pipe-lines, etc. Also look to clear paths for wheelbarrows and other movement. Layout the excavation using the marking device and tape measure to position and set the outline. Then use a spade to clearly finalize the perimeter mark. Plan for use or disposal of excavated soil of which the final amount is difficult to visualize prior to start.

    EXCAVATION

    Begin by forming the vertical walls with a slight inward slope to maintain some stability. Carve the wall around the entire perimeter and remove the soil down to 12" deep. Define a level upper edge using any practical method to achieve accuracy to 1/4 to 1/2". This step is vital in assuring the liner is completely hidden at the waterline. Form shelves if desired as excavation is continued. Shelves should be 12" deep and only as wide as needed to accommodate plant containers, which are typically 10 to 16" in diameter. Shelves may ultimately limit flexibility during aquatic plant placement/stocking and increase the potential for predation as well; in which case you may want to not include shelves and consider using items such as bricks, blocks, or similar to support planting containers to desired depths.

    Check the depth periodically and form a relatively flat bottom. The final depth of the excavation should be 1" over the desired pond depth. Clean the excavation by removing any sharp or rigid objects such as rocks or tree roots that may cause damage to the liner. Prepare the excavation with Liner Underlayment on vertical sides and approximately 1" of sand on horizontal areas. The overall consideration must be the fact that the excavation is the structural "backbone" of the pond. Carve into existing soil whenever possible and avoid backfilling and packing loose soil.

    PLACEMENT OF THE LINER

    Unfold Liner completely if possible, and refold so liner may be lifted (with assistance) and carried/placed into the excavation to avoid dragging the liner. Work the folds as the liner is placed to minimalize the number of smaller folds by forming a few larger creases. Fill the lined excavation to about 80-90% capacity with water before finalizing the edging to assure total conformation of the liner into the excavation.

    CREATE THE FINAL EDGING

    Consider safety first by forming a secure edge especially where foot traffic is likely. Consider all options (they are numerous) by looking at books, pictures, and actual gardens to get ideas. The easiest options are simply setting large rocks, (for informal ponds) or cut flagstones, (for formal ponds) around the pond edge directly on the liner at or just below the water-line. Setting these items in a reinforced 2-3" base of mortar (optional) creates a more secure edge. Incorporate plantings into informal edging to "break up" the unnatural effect created by the "necklace" of edge rock. Final trimming of the liner should be performed after the edging is completed.

    INSTALLING A PRE-FORMED (RIGID) LINER

    TOOLS: Same as for flexible liner, except a device for marking is not required.

    SITE PREPERATION: Same as flexible liner (see previous) except the excavation is laid out by setting the pond liner into the desired position, and upright. Then define/ mark an outline approx. 4-6" beyond the liner edge.

    EXCAVATION

    Simply "rough out" a hole slightly larger and deeper by a few inches than the liner to allow room for backfilling. If the liner has shelves excavate to the shelf depth first, then mark the edge of the shelf into the excavation bottom then excavate the remainder. Do not use excess soil to backfill as sand is far less likely to shift during settling. Finalize the excavation confirming it is several inches deeper than the liner. Then add enough sand in the bottom to set the liner's upper edge slightly above the surrounding existing grade. Level the pond liner using a straight board and carpenter level to incrementally check the entire pond edge, noting high/low points. Now remove the liner and use a garden rake to move the sand from higher points to lower points. Replace the liner and re-check the level. Repeat this process until a satisfactory level is achieved.

    Patience may be required though it will be worth it. Once the liner is set and level begin to fill it with water. Now begin to backfill with sand as evenly as possible around the entire liner. Try to maintain the backfill level as evenly as possible with the filling water level to maintain even pressure on both sides of the liner wall. Use a shovel handle or similar item to "tamp" or pack the sand during this step. Once the liner is full and backfill complete the next step is edging.

    CREATE THE FINAL EDGING: The same basic methods that apply to flexible liners will work with rigid liners. There are limits though, as certain types of advanced edging techniques will not work with rigid liners.

    FLEXIBLE LINERS OR PRE-FORMED (RIGID) LINERS?

    Advantages of Flexible Liners:
  • Allows more choices in size, shape, and depth.
  • Least expensive pond material.
  • Allows many options for edging.
  • Better suited for creating waterfalls.
  • Easy and inexpensive to repair.

    Advantages of Pre-formed Liners:
  • Somewhat easier to install.
  • Higher quality models* are a strong permanent material.
  • Higher quality models* may be installed without excavating.

    * Higher quality models are made of fiberglass.