Code of Federal Regulations Title 40. Protection of Environment § 40.265.253 Containment

(a)(1) The pile must be placed on an impermeable base that is compatible with the waste under the conditions of treatment or storage;

(2) The owner or operator must design, construct, operate, and maintain a run-on control system capable of preventing flow onto the active portion of the pile during peak discharge from at least a 25–year storm;

(3) The owner or operator must design, construct, operate, and maintain a run-off management system to collect and control at least the water volume resulting from a 24–hour, 25–year storm;  and

(4) Collection and holding facilities (e.g., tanks or basins) associated with run-on and run-off control systems must be emptied or otherwise managed expeditiously to maintain design capacity of the system;  or

(b)(1) The pile must be protected from precipitation and run-on by some other means;  and

(2) No liquids or wastes containing free liquids may be placed in the pile.