The trap is being placed in an area with a clay base, and clay has a permeability of approximately 3.28084 x 10^-11 ft/sec.  Assume that the clay extends for 10 ft around the trap.

10 ft / (3.28084 x 10^-11 ft/sec x 60 sec/min x 60 min/hr x 24 hr/day) = 3,527,777 days for water to travel through the clay to saturate the clay causing bouyancy.  The only amount of water to form around the trap will most likely be from rainfall.

Bouyancy is calculated :
Assume,Water = 62.4 #/ft^3
Assume, Gravity = 32.2 ft/s^2
Volume of grease trap = 47 ft^3  (Assume water level is at 1/8 of the depth of the grease trap, therefore volume below water = 5.875 ft^3

Bouyance = water density x gravity x volume
	= 62.4  x 32.2  x 5.875 = 11,804 #

Grease Trap Empty Weight = 283 #;  Force necessary to keep grease trap from poping out of ground 
11,804 - 283 = 11,521 # 

Divide this force by the four corners = 2,880 # at each corner

The model of trap being installed has ridges on the sides of the trap and the trap itself is sloped with a large bottom and smaller at the top, therefore resisting uplift.

The achor ShelterLogic is a 30 inch corkscrew design and gives approximately 1200 # of resisting force.