9.11.100 Construction Site Best Management Practices.
A. Any person performing construction activities in the City shall implement appropriate BMPs to prevent the discharge of construction wastes or pollutants from construction materials, tools, and equipment from entering the storm drain system or watercourse. Pollutants associated with construction activity include but are not limited to sediment, fertilizers, pesticides, paints, solvents and fuels.
B. The City has the authority to review designs and proposals for construction activities to determine whether adequate BMPs will be installed, implemented, and maintained during construction and after final site stabilization.
C. Construction site 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.
D. Erosion and Sediment Control Plan Requirements.
1. When required by the Phase II Stormwater Permit or by the City, a construction project shall have an Erosion and Sediment Control Plan (ESCP) that addresses erosion and sediment control and pollution prevention during the construction phase as well as final stabilization control measures. The ESCP shall be implemented year round. An ESCP shall be required for any construction project that:
a. Requires a grading permit under Larkspur Municipal Code Chapter 15.20, Grading, Excavation, and Fills;
b. Requires a building permit, encroachment permit, demolition permit, or other permit that has the potential for significant erosion and/or significant nonstormwater discharges of sediment and/or construction site waste; or
c. Is determined necessary, in the City’s reasonable discretion after considering factors such as whether the project involves hillside soil disturbance, rainy season construction, construction near a watercourse, or any other condition or activity that poses a threat to water quality or could lead to a nonstormwater discharge if not managed by effective implementation of an ESCP.
2. The construction project applicant shall submit the ESCP for review and written approval by the City. The ESCP shall be revised to reflect changing conditions on the project site. The City shall require modifications of an approved ESCP if, during the course of construction at a site, unanticipated conditions occur or the plans prove inadequate for the intended purpose. Revisions of the approved ESCP shall be submitted to the City for review and approval.
3. In developing the ESCP, the project applicant shall follow the most recent version of the MCSTOPPP Construction Erosion and Sediment Control Plan Applicant Package. At a minimum, the ESCP shall include:
a. Description of the proposed project and soil disturbing activity;
b. Site specific construction-phase BMPs;
c. Rationale for selecting the BMPs including supporting soil loss calculations, if necessary;
d. List of applicable permits associated with the soil disturbing activity, such as: Construction General Permit (CGP); Clean Water Act Section 404 Permit; Clean Water Act Section 401 Water Quality Certification; Streambed/Lake Alteration Agreement (1600 Agreements).
4. If the project requires coverage under the Construction General Permit (CGP) issued by the State Water Resources Control Board, permit registration documents must be filed with the State Water Resources Control Board for said coverage and a copy of the Waste Discharge Identification Number shall be submitted to the City prior to issuance of a permit for construction activity. The applicant may submit the Stormwater Pollution Prevention Plan (SWPPP) required by the CGP in lieu of the ESCP provided it meets the requirements of the ESCP.
5. Implementation of an approved ESCP shall be a condition of the issuance of a building permit, a grading permit, encroachment permit, demolition permit, or other permit issued by the City for a project subject to this section. In order to obtain a grading permit, the project applicant shall also submit evidence to the City that all permits directly associated with the grading activity have been obtained prior to commencing the soil disturbing activities authorized by the grading permit.
E. Financial security may be required to ensure 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.
F. The authorized enforcement official has a right to inspect the construction site to verify compliance with this chapter. Inspections shall include, at a minimum, maintenance of BMPs, effectiveness of BMPs installed, and verification that pollutants of concern are not discharged into watercourse. At the conclusion of construction, the authorized enforcement official has a right to inspect the site to ensure that all disturbed areas have been stabilized and that all temporary erosion and sediment control measures that are no longer needed have been removed.
G. If the authorized enforcement official determines, in their reasonable discretion, that the construction site does not contain the proper BMPs or is otherwise not compliant with the requirements of this chapter, the authorized enforcement official may order the construction site operator to cease and desist any construction activity until such violations are cured. Such order shall be issued in writing served on the construction site operator or any other person overseeing the construction activity. The authorized enforcement official may also take additional corrective or enforcement actions consistent with the City’s Enforcement Response Plan and the remedies available in the City’s Municipal Code. (Ord. 1062 § 14, 2022; Ord. 1030 § 2(7), 2018; Ord. 1005 § 2, 2015)