14.28.081 Best management practices for ground-disturbing activities.

Any person performing construction activities in the city shall implement appropriate BMPs to prevent the discharge of sediment, construction wastes or contaminants from construction materials, tools and equipment from entering a city storm drain or watercourse.

(A) Construction-phase BMPs include erosion and sediment controls and pollution prevention practices. Erosion control BMPs may include, but are not limited to, scheduling and timing of grading activities, timely revegetation of graded areas, the use of hydroseed and hydraulic mulches, and installation of erosion control blankets. Sediment control may include properly sized detention basins, dams, or filters to reduce entry of suspended sediment into the storm drain system and watercourses, and installation of construction entrances to prevent tracking of sediment onto adjacent streets. Pollution prevention practices may include designated washout areas or facilities, control of trash and recycled materials, tarping of materials stored on-site, and proper location of and maintenance of temporary sanitary facilities. The combination of BMPs used, and their execution in the field, must be customized to the site using up-to-date standards and practices. The city will provide references to current guidance manuals and BMP information on request.

(B) Financial security may be required to insure that temporary measures to control stormwater pollution are implemented and maintained during construction and after construction for a period determined by the city. Financial security shall consist of an irrevocable letter of credit, cash deposit, or performance bond as determined by the city.

(C) When any work is being done contrary to the provisions of this chapter, the authorized enforcement official may order the work stopped by notice in writing served on any persons engaged in doing or causing the work to be done. Such work shall stop until the authorized enforcement official authorizes the work to proceed. This remedy is in addition to and do not supersede or limit any and all other remedies, both civil and criminal provided in the city municipal code.

(D) The city has the authority to review designs and proposals for construction activities and new development and redevelopment sites to determine whether adequate BMPs will be installed, implemented, and maintained during construction and after final stabilization (post-construction).

(E) All construction plans and applications for construction activity submitted to the city shall consider the potential for erosion and sedimentation at the construction site, and shall include appropriate erosion and sedimentation controls.

(F) An Erosion and Sediment Control Plan (ESCP) shall be required for:

(1) Any project subject to a grading permit under Appendix J of the California Building Code;

(2) Any project subject to building permit that has the potential for significant erosion and/or significant non-stormwater discharges of sediment and/or construction site waste including:

(a) Projects within fifty feet of the storm drain system, or

(b) Project disturbing ten thousand square feet (sf) of soil or more, or

(d) Projects on slopes of five percent or more;

(3) Any other project as required by the authorized enforcement official considering factors such as whether the project involves hillside soil disturbance, rainy season construction, construction near a watercourse, or any other condition or construction site activity that could lead to a non-stormwater discharge to a storm drain if not managed by effective implementation of an ESCP.

(G) The ESCP shall be submitted for review and approval by the authorized enforcement official. The project applicant shall follow the most recent version of the Napa Countywide Erosion and Sediment Control Plan Model Template and any issued Technical Bulletins to prepare the ESCP. At a minimum, the ESCP shall include:

(1) Description of the proposed project and soil disturbing activity.

(2) Site specific construction-phase BMPs.

(3) Rationale for selecting the BMPs, including if needed, soil loss calculations.

(4) List of applicable permits associated with the soil disturbing activity, including but not limited to: Construction General Permit (CGP); Clean Water Act Section 404 Permit; Clean Water Act Section 401 Water Quality Certification; Streambed/Lake Alteration Agreement (1600 Agreements).

(5) Proof that the applicant has obtained the applicable permits associated with the soil disturbing activity must be submitted prior to approval of the ESCP.

(6) Project information as required by the ESCP applicant checklist provided in the Napa Countywide Erosion and Sediment Control Plan Model Template and any issued Technical Bulletins.

(7) For projects subject to the State's General Construction Activity Stormwater Permit (CGP), project applicants may submit a Stormwater Pollution Prevention Plan (SWPPP) developed pursuant to the CGP in lieu of submitting an ESCP.

(8) Implementation of an approved ESCP shall be a condition of the issuance of a building permit, a grading permit, or other permit issued by the city for a project subject to this section. The ESCP shall be implemented year round and must be updated to reflect changing conditions on the project site. Any modifications to the ESCP shall be submitted to the city for review and approval.