Marin County Municipal Code Art. 1 Title, Purpose and General Provisions

The ordinance codified in this chapter shall be known as the "County of Marin Stormwater Runoff Pollution Prevention Ordinance" and may be so cited.

(Ord. 3225 § 2 (part), 1996)

(Ord. No. 3631, § II, 2015)

The purpose of this chapter is to ensure the future health, safety and general welfare of Marin County residents and to protect and enhance watercourses, and fish and wildlife habitat by:

(a) Minimizing discharges other than storm runoff to storm drains or watercourses;

(b) Responding to the discharge of spills, preventing and controlling the discharge of spills to storm drains or watercourses and prohibiting dumping or disposal of materials other than stormwater;

(c) Reducing pollutants in stormwater discharges to the maximum extent practicable;

(d) Requiring operators of construction sites, new or redeveloped land, and industrial and commercial facilities to install, implement, or maintain appropriate best management practices (BMPs); and

(e) Maintaining pre-development stormwater runoff rates and preventing nonpoint source pollution whenever possible, through stormwater management controls and ensuring that these management controls are properly maintained.

The intent of this chapter is to protect and enhance the water quality of our watercourses, water bodies and wetlands in a manner pursuant to and consistent with the Clean Water Act, the Porter-Cologne Water Quality Control Act (California Water Code Section 13000 et seq.), and the Phase II Small Municipal Separate Storm Sewer System (MS4) National Pollutant Discharge Elimination System (NPDES) Permit, Water Quality Order No. 2013-0001-DWQ, General Permit No. CAS000004 (phase II stormwater permit) and subsequent revisions and amendments thereto.

(Ord. 3486 § 1 (part), 2008; Ord. 3439 § 9, 2006: Ord. 3225 § 2 (part), 1996)

(Ord. No. 3631, § II, 2015)

All parcels used for commercial agricultural operations are exempt from the provisions of this chapter.

(Ord. 3225 § 2 (part), 1996)

Any terms defined in the phase II stormwater permit, the federal Clean Water Act and acts amendatory thereof or supplementary thereto, and/or defined in the regulations for the stormwater discharge permitting program issued by the Environmental Protection Agency on November 16, 1990 (as may from time to time be amended) as used in this chapter shall have the same meaning as in that statute or regulations. The terms below, when used in this chapter, shall have the following meanings:

(a) "Agency" means the public works department of the county of Marin, unless otherwise stated.

(b) "Area of special biological significance" (ASBS) means those areas designated by the California State Water Resources Control Board as ocean areas requiring protection of species or biological communities to the extent that alteration of natural water quality is undesirable. All areas of special biological significance are also classified as a subset of state water quality protection areas. ASBS are also referred to as state water quality protection areas—areas of special biological significance.

(c) "ASBS compliance plan area (CPA)" means the area near the unincorporated community of Bolinas that is within the Duxbury Reef ASBS watershed where the county of Marin has jurisdiction.

(d) "BASMAA Post Construction Manual" means the most recent version of the Bay Area Stormwater Management Agencies (BASMAA) Post Construction Manual which provides design guidelines for reducing stormwater pollutant discharges through the construction, operation and maintenance of source control measures, low impact development design, site design measures, stormwater treatment measured and hydromodification management measures.

(e) "Best management practices (BMPs)" means schedules of activities, prohibitions of practices, general good housekeeping practices, pollution prevention practices, maintenance procedures, and other management practices to prevent or reduce the discharge of pollutants directly or indirectly to waters of the United States. BMPs also include treatment requirements, operating procedures and practices to control site runoff, spillage or leaks, sludge or waste recycling or disposal, or drainage from raw material storage.

(f) "County" means the unincorporated area of Marin County.

(g) "Discharge of a pollutant" means the addition of any pollutant or combination of pollutants to waters of the United States from any point source, or any addition of any pollutant to the waters of the contiguous zone or the ocean from any point source other than a vessel or other floating craft which is being used as a means of transportation. The term includes additions of pollutants to waters of the United States from: surface runoff which is collected or channeled by man; discharges through pipes, sewers, or other conveyances owned by a state, municipality, or other person which do not lead to a treatment works; and discharges through pipes, sewers, or other conveyances, leading into privately owned treatment works.

(h) "Hydromodification" means modification of hydrologic pathways (precipitation, surface runoff, infiltration, groundwater flow, return flow, surface water storage, groundwater storage, evaporation and transpiration) that results in negative impacts to watershed health and functions.

(i) "Illicit connection" means any device or method that conveys nonstormwater to a municipal separate storm sewer (storm drain) system (MS4) or receiving water.

(j) "Illicit discharge" means any discharge to a municipal separate storm sewer (storm drain) system (MS4) that is prohibited under local, state, or federal statutes, ordinances, codes, or regulations. The term "illicit discharge" includes all discharges that are identified under the discharge prohibition section of the phase II stormwater permit and all nonstormwater discharges not composed entirely of stormwater. The term "illicit discharge" does not include discharges that are regulated by an NPDES permit (other than the NPDES permit for discharges from the MS4).

(k) "Incidental irrigation runoff" means unintended amounts (volume) of runoff, such as unintended, minimal over-spray from sprinklers that escapes the landscaped area of intended use. Water leaving an intended use area is not considered incidental if it is part of the facility design, if it is due to excessive application, if it is due to intentional overflow or application, or if it is due to negligence.

(l) "Low Impact Development (LID)" means a sustainable practice that benefits water supply and contributes to water quality protection. LID uses site design and stormwater management to maintain the site's pre-development runoff rates and volumes. The goal of LID is to mimic a site's predevelopment hydrology by using design techniques that infiltrate, filter, store, evaporate, and detain runoff close to the source of rainfall.

(m) "MCSTOPPP" means the Marin County Stormwater Pollution Prevention Program.

(n) "Maximum extent practicable (MEP)" means the minimum required performance standards, BMPs, control techniques and systems, design and engineering methods, and such other provisions as the Environmental Protection Agency Administrator or the state determines appropriate for reducing pollutants in stormwater. MEP is the cumulative effect of implementing, evaluating, and making corresponding changes to a variety of technically appropriate and economically feasible BMPs, ensuring that the most appropriate controls are implemented in the most effective manner. This process of implementing, evaluation, revising, or adding new BMPs is commonly referred to as the iterative process.

(o) "NPDES permit" means a National Pollutant Discharge Elimination System permit issued by the United States Environmental Protection Agency, the state water resources control board, or a California Regional Water Quality Control Board pursuant to the Clean Water Act that authorizes discharges to the waters of the United States.

(p) "Nonstormwater discharge" means any discharge that is not entirely composed of stormwater.

(q) "Pollutant" means dredged soil, solid waste, incinerator residue, filter backwash, sewage, biological materials, pet wastes, manure, garbage, sewage sludge, munitions, chemical wastes, radioactive materials, heat, wrecked or discarded equipment, sediment, cellar dirt, dumped yard wastes, and industrial, municipal, and agricultural waste; or sand and gravel placed in such a way as to be carried away by stormwater into the storm drains and watercourses of the county.

(r) "Premises" means any building, lot, parcel, real estate, or land or portion of land whether improved or unimproved, including adjacent sidewalks and parking strips.

(s) "Storm drains" includes but is not limited to those facilities within the county by which stormwater may be conveyed to waters of the United States, including any roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels or storm drains, which are not part of a publicly owned treatment works (POTW) as defined at 40 Code of Federal Regulations (CFR) 122.2.

(t) "Stormwater" or "storm runoff" means or includes stormwater runoff, snow melt runoff, and surface runoff and drainage.

(u) "Stormwater control plan (SCP)" means a plan that meets those criteria contained in the most recent version of the BASMAA Post Construction Manual.

(v) "Stormwater facilities operation and maintenance plan (O&M plan)" means a plan identifying the locations and characteristics of stormwater management facilities on a newly developed or redeveloped site and describing maintenance activities, schedules, and responsibilities to ensure the ongoing proper operation of those facilities.

(w) "Stormwater management facility" means any device designated to detain, retain, filter, or infiltrate stormwater, including, but not limited to, bioretention facilities.

(x) "Urbanized area" means a densely settled core of census tracts and/or census blocks that have a population of at least fifty thousand, along with adjacent territory containing nonresidential urban land uses as well as territory with low population density included to link outlying densely settled territory with the densely settled core.

(y) "Watercourse" means any natural or once natural flowing river, creek, stream, swale or drainageway, whether perennial, intermittent or ephemeral. Includes natural waterways that have been channelized but does not include channels, ditches, culverts or other above or below ground constructed conduits, i.e., storm drains.

(Ord. 3486 § 1 (part), 2008; Ord. 3225 § 2 (part), 1996)

(Ord. No. 3631, § II, 2015)

This chapter shall be administered for the county by the agency. Where storm drains and/or watercourses have been accepted for maintenance by a public agency legally responsible for certain storm drains and/or watercourses, then the responsibility for enforcing the provisions of this chapter may be assigned to such agency (through contract or agreement with the county) with respect to those storm drains and/or watercourses for which they have accepted maintenance. In administering this chapter, the agency has the authority to request and require the submittal of information deemed necessary to assess compliance with this chapter and the phase II stormwater permit.

(Ord. 3225 § 2 (part), 1996)

(Ord. No. 3631, § II, 2015)

This chapter shall be construed to assure consistency with the requirements of the federal Clean Water Act and acts amendatory thereof or supplementary thereto, and applicable implementing regulations, including the current and future versions of the water quality control plan for the San Francisco Bay basin and the phase II stormwater permit.

(Ord. 3486 § 1 (part), 2008; Ord. 3225 § 2 (part), 1996)

(Ord. No. 3631, § II, 2015)

The first revision of the business plan for any facility subject to County Code Chapter 7.90 (Hazardous Materials Release Response Plans and Inventories) shall include a program for compliance with this chapter, including the prohibitions on illicit discharges, and the requirement to reduce stormwater pollutants to the maximum extent practicable.

(Ord. 3225 § 2 (part), 1996)

(Ord. No. 3631, § II, 2015)