Noteworthy changes to the 2018 Colorado Discharge Permit System (CDPS) General Permit for Stormwater Discharges Associated with Construction Activities (COR-400000)

February 16, 2019

A new Construction General Permit will be in effect starting April 1, 2019. Existing active permits after the effective date will be transferred to the new permit and do not need to reapply.  The new permit requirements must be incorporated into SWMPs, site management and field compliance practices.

• The owner and operator are co-permittees (must sign permit) and are subjected to the compliance with all terms and conditions.
• Dewatering of groundwater or stormwater with a groundwater component that meets the Low Risk Guidance Document must be discussed in the SWMP, but it is not covered under the 2018 General Permit, rather the Low Risk Guidance doc
• Construction activities in response to a public emergency must apply for coverage under the General Permit within 14 days of commencement of construction
• SWMP is no longer required for application, however, is required before construction activities commence
• Terminology changed from “best management practices” to “control measures”
• Effluent limitations were added to the permit.  The following control measures must be used to meet effluent limitations:
  • VTC must be implemented, but may not be required if tracking areas are treated by another control measure (temporary or permanent stabilization, filtering, settling or straining capabilities)
  • Runoff from all disturbed and stockpile areas without stabilization must flow to at least one control measure
  • Maintain pre-existing vegetation for areas within 50ft of receiving waters, unless infeasible.  This must also be described in the SWMP and illustrated on the site map
  • Soil compaction must be minimized for areas where infiltration control measures are planned or vegetative cover is the proposed final stabilization
  • Where ground disturbance has ceased temporarily or permanently for 14 days temporary stabilization must be implemented
  • A method for determining pre-disturbance vegetative cover must be included in the SWMP including actual cover and vegetation type
• All stream crossings and associated control measures within the limits must be described in the SWMP and on the site maps
• If control measures are used outside the limits, an agreement must be established
• Site maps must include flow arrows
• “SWMP Administrator” has changed to “Qualified Stormwater Manager”
• Inspection frequency may either be once every 7 days or once every 14 days and with 24hrs of runoff producing events.  The first inspection must be within 7days of construction commencement
• SWMP can now be stored electronically onsite
• Changes were made to inspection report requirements to allow inspectors to identify control measures that require maintenance but have not failed

Additional Resources:

Free trainings provided by CDPHE

CDPHE General Permit page