Step 1
Stake out the location of the lagoon based on approved construction drawings.
Step 2
Excavate the lagoon to a minimum depth of 5 feet, and stack the fill to create berms. Ensure that the bottom of the lagoon is flat and the sides have a 3:1 slope.
Step 3
Excavate a 2-foot-wide area for the inlet pipe (and overflow pipe if required), to a depth that will accomodate the pipe plus two layers of aggregate and a layer of fill. Lay down 4 inches of clear aggregate in the trench.
Step 4
Install the inlet pipe from the house to the pond edge, ensuring that there is a positive slope -- the ideal slope is 1.4 inch per foot. Install cleanout valves every 75 feet. Install the overflow pipe with a positive slope to discharge the area. Cover the pipe with clear aggregate and fill the excavated area to the surface.
Step 5
Compact 6 inches of soil in the bottom and on the sides of the lagoon, with a roller. Add two more layers of soil for an additional depth of 12 inches.
Step 6
Extend the inlet pipe to the center of the lagoon and secure it to a poured-in-place concrete slab (2-by-2 feet minimum). Install the EPDM liner (or equivalent), if required.
Step 7
Hydroseed the lagoon sides and berm with the grass mixture. Allow effluent to fill the lagoon to an ideal depth of 2 to 5 feet. Install a safety fence at the perimeter.