5 Colo. Code Regs. § 1002-72.28
The provisions of 25-8-202(1)(c), and (2) and 25-8-205, C.R.S. provide the specific statutory authority for adoption of these regulatory amendments. The Commission also adopted, in compliance with 24-4-103(4) C.R.S., the following statement of basis and purpose.
BASIS AND PURPOSE
In this rulemaking, changes were made to Section 72.7 Stormwater Permit Requirements only. These changes were recommended by the Cherry Creek Basin Water Quality Authority to incorporate revised water quality control strategies based on recent studies, information and conditions. The Authority has express statutory authority to develop and revise such strategies under C.R.S. 25-8.8-111(1)(a).
The adopted changes clarify specific areas that are covered by stormwater requirements and provide consistency between State and Federal stormwater requirements. The changes are based on experience the Authority has gained in recent years, will improve the effectiveness of its Regulation 72 stormwater program, and address limited situations where the Commission believes certain BMPs are not practicable. Regulation 72 was modified to clarify that post-construction stormwater controls for new development and redevelopment can include structural and/or non-structural controls, as may be appropriate for the local situation. Use of non-structural BMPs in some cases may provide for a more effective and efficient solution to meet the overall goal of controlling pollutants and is consistent with the requirements in Regulation 61. Specifically, a new non-structural BMP, "Runoff Reduction Practices," was added to Regulation 72.7.2(c)(6), and the Large Lot Single Family Development provision that incorporates this BMP is now automatically excluded from additional post-construction BMP requirements under Regulation 72. The Commission finds that the implementation of Runoff Reduction Practices to Large Lot Single Family Development will result in infiltration of the Water Quality Capture Volume and thus not require other Regulation 72 structural post-construction BMPS and associated administrative requirements.
Similarly, the Commission has determined that it is also appropriate to exclude a limited subset of roadway projects, as defined at 72.7.1(d), from Regulation #72 post-construction requirements that it finds are not practicable for these projects. This is not intended to exclude roadway de-icing operations and drainage improvements associated with roadway maintenance. These activities would not be expected to cause increased stormwater quality impacts, as compared to pre-project conditions, as the original footprint for Excluded Roadway Projects would not be changed, and there would be no additional runoff due to the limitation on no increase in impervious area.
The Commission has also added language to Section 72.7 that authorizes MS4 permittees to modify schedules for stabilization and revegetation to allow for physical considerations adverse to stabilization or revegetation goals. This flexibility has been provided to address situations where physical constraints exist that would result in making the stabilization and revegetation schedules in Regulation 72 impracticable.
Typographical errors and cross- references were also corrected. Clarifications were made to several definitions, and language was added to ensure that Regulation 72 is consistent with the language of Regulation 61.
These changes are not intended to define "new development and redevelopment" as used in Regulation 61, nor to modify MS4 permit construction program requirements or permit requirements defined in Regulation 61. The Commission supports the ongoing efforts between the Division and the MS4 community to define "new development and redevelopment" in accordance with Regulation 61.
PARTIES TO THE RULEMAKING
5 CCR 1002-72.28