GRADING THE WATERCOURSE SITE
 AND CREATING A CATCH BASIN
If you are using a flexible liner to create and build your pond you must first grade the site.  If working on ground that is flat, you may want to rough out the shape of your lined Koi pond before you begin to change the grade.  You can then build up a mound of compacted soil next to the lined stream at your waterfall location.  This is a good way to make use of the soil dug from the pond.  Make the mound wide enough to accommodate the pond's liner with sufficient space around the perimeter for rocks, plants and other landscaping materials.  Tap down the soil firmly to compact it.  Gently slope the sides away from the area to be excavated to prevent rain from washing dirt into the lined pond area.   Try to avoid steeply sloped mounds.  They will not only look unnatural, but will be more prone to soil erosion.  When working on a naturally sloped site, it will dictate the shape of your lined pond to a great extent, especially if it is very rocky.

Working on your slope, natural or otherwise, cut a series of level steps to create what icon looks like a staircase.  Each step will serve as a catch basin for your waterfall or stream.  For a stream, you will have long steps with short risers: creating a steep waterfall will require icon shorter steps with taller risers.  When building your lined pond, make each step large enough to accommodate rocks or other materialsicon used for edging.  The same holds true if you will be using concrete supporting blocks.

When creating a catch basin for your lined pond,  you will want each of your stair steps to hold water even when the pump is turned off.  This is a good way to achieve a natural look.  There are several different ways to achieve this.  If you are using concrete block supports with youricon lined pond, they will form the sides of your catch basin. (If your soil is either or flinty, use of the concrete block supports is essential.)  Even though they will look straight and artificial, you will make them look more natural later with your artful placement of rocks on top of and around them. icon

Begin by digging your steps and shape it so that it slopes slightly backward, away from the pond.  If you are working with clay solid that packs down tightly, concrete blocks may not be necessary.  You can, instead, dig a catch basin in the middle of icon each stair.  Be sure to leave a ledge of earth on which you can place your edging stones.  If the pond area is large enough, you may want to make another ledge around the perimeter where you can place partially submerged boulders.  Keep in mind that the finished lined pond you created will look smaller that the excavated holes once the rocks and other edging materials are in place along the sides.  Put some teeth into your digging.  The super shovel shown at right, slices through roots, rocky soil and baked clay with ease.

Since the catch basins are just mini versions of the main pond, you must make sure they are level.  As with your pond, your watercourse, stream or waterfall should be level across its width.  To make sure that it is be sure to use a spirit level placed on top of a 2 x 4.