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Step 10 – Level Three Corrective Action: Treatment

Here are the steps for a Level 3 Corrective Action.  Please refer to the permit and/or your consultant or your Ecology contact for more information.

  1. Conduct a Level One Action
  2.  Review the SWPPP and ensure that it fully complies with Permit Condition S3.
  3. Make appropriate revisions to the SWPPP to include treatment BMPs with the goal of achieving the applicable benchmark value(s) in future discharges. Revisions shall include additional operational and/or structural source control BMPs if necessary for proper performance and maintenance of treatment BMPs.

For a Level 3, you must have a qualified industrial stormwater professional review your revised SWPPP, sign the
SWPPP Certification Form, and certify that it is reasonably expected to meet the Permit benchmarks when implemented.  This requirement can be waived by Ecology, upon written request, one time during the permit cycle, on a case-by-case basis if you can demonstrate that the proposed Level 3 treatment BMPs are reasonably expected to meet the benchmarks when implemented.

Engineering Report Required

Before designing or installing any treatment BMPs you must submit an engineering report to Ecology for review.

The engineering report must include:

  • A brief summary of the treatment alternatives considered and why the proposed option was selected. Include cost estimates of ongoing operation and maintenance, including disposal of any spent treatment media;
  • The basic design data, including characterization of stormwater influent, and sizing calculations of the treatment units;
  • A description of the treatment process and operation, including a flow diagram;
  • The amount and kind of chemicals used in the treatment process, if any.
    Note: Use of stormwater treatment chemicals requires a submittal of a Request for Chemical Treatment Form;
  • Results to be expected from the treatment process including the predicted stormwater discharge characteristics;
  • A statement, expressing sound engineering justification through the use of pilot data, results from similar installations, and/or scientific evidence that the proposed treatment is reasonably expected to meet the permit benchmarks; and
  • Certification by a licensed professional engineer.
  • The engineering report must  be submitted no later than the May 15th prior to the Level 3 deadline, unless an alternate due date is specified in an order from Ecology
  • An Operation and Maintenance Manual (O&M Manual) shall be submitted to Ecology no later than 30 days after construction/installation is complete; unless an alternate due date is specified in an order from Ecology.
  • Summarize the Level 3 Corrective Actions (planned or taken) in the Annual Report.  Include information on how monitoring, assessment or evaluation information was (or will be) used to determine whether existing treatment BMPs will be modified/enhanced, or if new/additional treatment BMPs will be installed.
  • Level 3 Deadline: The Permittee shall sign/certify and fully implement the revised SWPPP
    according to Permit Condition S3 and the applicable Stormwater Management Manual as
    soon as possible, but no later than September 30th of the following year.
  • a. If an installation of necessary treatment BMPs is not feasible by the Level 3 Deadline;
    Ecology may approve additional time by approving a Modification of Permit Coverage.
    b. If an installation of treatment BMPs is not feasible or not necessary to prevent discharges
    that may cause or contribute to a violation of a water quality standard, Ecology may waive
    the requirement for treatment BMPs by approving a Modification of Permit Coverage.
    c. To request a time extension or waiver, a Permittee shall submit a detailed explanation
    of why it is making the request (technical basis), and a Modification of Coverage form to
    Ecology in accordance with Condition S2.B, by May 15th prior to the Level 3 Deadline.
    Ecology will approve or deny the request within 60 days of receipt of a complete
    Modification of Coverage request.
    d. While a time extension is in effect, benchmark exceedances (for the same parameter)
    do not count towards additional Level 2 or 3 Corrective Actions.
    e. For the year following the calendar year, the Permittee triggered a Level 3 corrective
    action, benchmark exceedances (for the same parameter) do not count towards
    additional Level 2 or 3 Corrective Actions.