When protection of adjoining property or waterways is by means of impounding by diking around the tanks, the system shall comply with the following:
   (A)   A slope of not less than 1% away from the tank shall be provided for at least 50 feet or to the dike base, whichever is less.
   (B)   The volumetric capacity of the dike area shall not be less than the greatest amount of liquid that can be released from the largest tank within the diked area, assuming a full tank.  To allow for volume occupied by tanks, the capacity of the diked area enclosing more than one tank shall be calculated after deducting the volume of the tanks, other than the largest tank, below the height of the dike.
   (C)   To permit access, the outside base of the dike at ground level shall be no closer than ten feet to any property line that is or can be built upon.
   (D)   Walls of the diked area shall be of earth, steel, concrete or solid masonry designed to be liquid tight and to withstand a full hydrostatic head.  Earthen walls three feet or more in height shall have a flat section at the top not less than two feet  wide.  The slope of an earthen wall shall be consistent with the angle of repose of the material of which the wall is constructed.  Dike areas for tanks containing Class 1 liquids located in extremely porous soils may require special treatment to prevent seepage of hazardous quantities of liquids to low-lying areas or waterways in case of spills.
   (E)   (1)   Every tank battery associated with a well or group of wells shall be separated from any other tank battery associated with any other well or wells by a dike of a height as required above.  A dike shall also be constructed to separate the crude storage tanks and water storage tanks from separators, heater treaters and other vessels.  The height of this dike shall meet the requirements specified above.
      (2)   The provisions of this section shall apply only to tanks or equipment installed, placed or replaced on or after the effective date of the ordinance by which this subsection was enacted.
   (F)   Where provision is made for draining water from diked areas, the drains shall be controlled in a manner so as to prevent flammable or combustible liquids from entering natural water courses, public sewers or public drains, if their presence would constitute a hazard.  Control of drainage shall be accessible under fire conditions from outside the dike.
(Ord. 2991, passed 7-19-94)