Section 20365 - SWRCB-Precipitation and Drainage Controls. [C15: Section 2546 // T14: Section 17778(e), (f)(1), (g), and (j)](a) General--Units and their respective containment structures shall be designed and constructed to limit, to the greatest extent possible, ponding, infiltration, inundation, erosion, slope failure, washout, and overtopping under the precipitation conditions specified in Table 4.1 (of this article) for each class of waste management unit (Unit). [Note: see also § 21090(b)(1).](b) Undiverted Precipitation--Precipitation on landfills or waste piles which is not diverted by covers or drainage control systems shall be collected and managed through the leachate collection and removal system, which shall be designed and constructed to accommodate precipitation conditions specified in Table 4.1 of this article or each class Unit.(c) Performance Standards--Diversion and drainage facilities shall be designed, constructed, and maintained: (1) to accommodate the anticipated volume of precipitation and peak flows from surface runoff under the precipitation conditions specified in Table 4.1 of this article for each class of Unit;(2) to effectively divert sheet flow runoff laterally, or via the shortest distance, into the drainage and collection facilities;(3) to prevent surface erosion through the judicious use of: (A) energy dissipators where required to decrease the velocity of runoff; and(B) slope protection and other erosion control measures;(4) to control and intercept run-on, in order to isolate uncontaminated surface waters from water that might have come into contact with waste;(5) to take into account: (A) for closed Units and for closed portions of Units, the expected final contours of the closed Unit, including its planned drainage pattern;(B) for operating portions of Units other than surface impoundments, the Unit's drainage pattern at any given time;(C) the possible effects of the Unit's drainage pattern on and by the regional watershed;(D) the design capacity of drainage systems of downstream and adjacent properties by providing for the gradual release of retained water downstream in a manner which does not exceed the expected peak flow rate at the point of discharge if there were no waste management facility; and(6) to preserve the system's function. Therefore, the discharger shall periodically remove accumulated sediment from the sedimentation or detention basins as needed to preserve the design capacity of the system.(d) Maintain Capacity--Collection and holding facilities associated with precipitation and drainage control systems shall be emptied immediately following each storm or otherwise managed to maintain the design capacity of the system.(e) Divert Drainage--Surface and subsurface drainage from outside of a Unit shall be diverted from the Unit.(f) Resist Erosion from Design Storm--Cover materials shall be graded to divert precipitation from the Unit, to prevent ponding of surface water over wastes, and to resist erosion as a result of precipitation with the return frequency specified in Table 4.1 (of this article) for each class of Unit, unless, for a landfill, the CIWMB/EA requires (for protection of public health and safety) that the design be capable of resisting erosion resulting from a longer return interval storm [see § 21150(b)]. Any drainage layer in the final cover shall be designed and constructed to intersect with the final drainage system for the Unit in a manner promoting free drainage from all portions of the drainage layer.Cal. Code Regs. Tit. 27, § 20365
1. New section filed 6-18-97; operative 7-18-97 (Register 97, No. 25). Note: Authority cited: Section 1058, Water Code. Reference: Sections 13172 and 13360, Water Code; and Section 43103, Public Resources Code.
1. New section filed 6-18-97; operative 7-18-97 (Register 97, No. 25).