5 Colo. Code Regs. § 1002-81.21
The provisions of sections 25-8-202(1)(c) and (2), 25-8-205, 25-8-401, 25-8-501.1, and 25-8-504, C.R.S. provide the specific statutory authority for the amendments to this regulation adopted by the Commission. The Commission has also adopted, in compliance with section 24-4-103(4), C.R.S., the following statement of basis and purpose.
BASIS AND PURPOSE:
Federal regulation 40 CFR 123.26 requires states that have been designated to administer federal regulations to adopt regulations that are at least as stringent as the corresponding federal regulations. Colorado has administered the federal Concentrated Animal Feeding Operations (CAFOs) under Regulation #81 since 1974. However, certain provisions of Regulation #81 are not as stringent as the federal CAFO regulations. The existence of these provisions has resulted in confusion among CAFO operators regarding what regulatory standards should be followed. In addition, some CAFOs may be in compliance with the state regulation but not with the federal regulations, which are still fully enforceable.
The Commission has determined that it is appropriate to modify the regulation by making certain provisions of the regulation equivalent to the federal CAFO regulatory requirements. Therefore, the regulation presently being adopted includes revisions to four (4) different sections. Section 81.2 was revised to reflect animal unit equivalency factors for animal species that are as stringent as those reflected in the federal regulations.
Sections 81.3 and 81.3 were revised to reflect the federal requirement that all CAFO facilities be designed, constructed, and operated to contain all process generated wastewaters plus the runoff from a 25-year, 24-hour rainfall event for the location of the CAFO. Section 81.3 was modified to delete Section 81.3 since it was inconsistent with this federal requirement.
The effect of the revisions to Sections 81.3 , 81.3 , and 81.3(C)(5)(1) is that the regulation now consistently indicates that CAFOs can only discharge as the result of receiving within a 24-hour period rainfall that is in excess of a 25-year, 24-hour rainfall event. In contrast, CAFOs that do not have sufficient storage capacity in their retention structures to retain all process wastewater plus the runoff resulting from any series of rainfall events occurring over a short period of time (days or weeks) (also known as chronic storm events) cannot discharge as the result of such a series of events unless covered as point sources under a discharge permit, per Section 61.3 of the Colorado Discharge Permit System regulations.
5 CCR 1002-81.21