§ 51.09  LIMESTONE AND GROUND WATER REQUIREMENTS.
   (A)   Absorption trench systems shall not be installed where there is less than 30 feet of cover above the limestone formations unless the following conditions are met:
      (1)   There must be a minimum of five feet of soil between the bottom of the absorption trench system and the limestone formation and that soil will provide a minimum of 20 years travel time prior to the effluent reaching the limestone formation.  This must be demonstrated by sufficient engineering data and it is the responsibility of the owner or subdivider to furnish this information.  All calculations of travel time shall be made assuming the maximum possible hydraulic gradient.
      (2)   The above requirement also applies to subdividing lots which have less than 30 feet of earth cover above limestone in which case it is the responsibility of the subdivider to provide sufficient information to either show the existence of 30 feet of cover above limestone or that the ground conditions will provide the protection of the water-bearing formations as specified above.
   (B)   No absorption trench systems shall be installed in areas where the permanent ground water table is less than four feet below the bottom of the trench system.  This depth of water table may be required to be confirmed by soil boring tests where indicated.
(1980 Code, §51.10)  (Sup. Rec. Bk.   , pp. 261—267, adopted 6-14-1976)  (Res. 07-412, adopted 10-18-2007; Ord. 14-279, passed 10-16- 2014; Ord. 16-235, passed 8-18-2016)  Penalty, see § 51.99