A. 
The purpose of this chapter is to protect and enhance coastal waters within the City of Carmel in accordance with the policies of the City's Local Coastal Plan (Sections O5-45 and O5-46), Sections 30230, 30231, 30232 and 30240 of the California Coastal Act, and the City's Phase II NPDES permit requirements. To implement the certified land use plan, application submittal requirements, development standards, and other measures are provided to ensure that permitted development shall be sited and designed to conserve natural drainage features and vegetation, minimize the introduction of pollutants into coastal waters to the maximum extent practicable, limit the discharge of stormwater runoff, and protect the overall quality of coastal waters and resources. All new development and redevelopment within the City shall comply with the requirements in this Chapter and in the City's Low Impact Development Guidance Manual (LID Guidance Manual) in Appendix I[1] to this chapter. (See Chapter 17.42 CMC and CMC § 17.42.020(D)(1)(b).)
[1]
Editor's Note: Said Appendix I is included as an attachment to this title.
B. 
The intent of this chapter is to address the following principles:
1. 
All development shall be evaluated by the Planning Director or his/her designee for potential adverse impacts to water quality and applicants should consider site design, source control and treatment control BMPs in order to minimize polluted runoff and water quality impacts resulting from the development. Site design BMPs reduce the need for source and/or treatment control BMPs, and source control BMPs may reduce the amount of treatment control BMPs needed for a development. Therefore, BMPs should be incorporated into the project design in the following progression:
a. 
Site design BMPs;
b. 
Source control BMPs;
c. 
Treatment control BMPs.
2. 
All development shall be designed to minimize the introduction of pollutants that may result in water quality impacts. Projects should be designed to control post-development peak runoff rates and average volumes to maintain or reduce pre-development downstream erosion rates. These objectives can be accomplished through the creation of a hydrologically functional project design that strives to mimic the existing natural hydrologic regime and by achieving the following goals:
a. 
Maintain and use existing natural drainage courses and vegetation;
b. 
Conserve natural resources and areas by clustering development on the least environmentally sensitive portions of a site while leaving the remaining land in a natural, undisturbed condition;
c. 
Minimize the amount of directly connected impervious surface and total area of impervious surface;
d. 
Incorporate or connect to existing on-site retention and infiltration measures;
e. 
Direct rooftop runoff to permeable areas rather than driveways or impervious surfaces to reduce the amount of stormwater leaving the site;
f. 
Minimize clearing and grading.
3. 
Incorporating these goals and principles into the project design will help to minimize the introduction of pollutants to the site and decrease the amount of polluted runoff leaving the site, resulting in the overall objective of water quality protection. Appendix I[2] to this chapter describes the requirements and processes for implementing BMPs into development and provides examples of types of BMPs to incorporate.
[2]
Editor's Note: Said Appendix I is included as an attachment to this title.
4. 
Nonstructural BMPs are preventative actions that involve management and source controls such as protecting and restoring sensitive areas such as wetlands and riparian corridors, maintaining and/or increasing open space, providing buffers along sensitive water bodies, minimizing impervious surfaces and directly connected impervious areas, and minimizing disturbance of soils and vegetation. Structural BMPs include: storage practices such as wet ponds and extended-detention outlet structures; filtration practices such as grassed swales, sand filters and filter strips; and infiltration practices such as infiltration basins and infiltration trenches. In many cases combinations of nonstructural and structural measures will be required to reduce water quality impacts.
5. 
Nonstructural and structural BMPs most applicable to the development projects are included in "A Planner's Guide to Conditions of Approval and Standard Mitigation Measures." Additional guidance on best management practices is available from the State, the EPA and from other sources such as BASMAA "Starting at the Source." Stormwater technologies are constantly being improved, and staff and developers must be responsive to any changes, developments or improvements in control technologies.
(Ord. 2004-02 § 1, 2004; Ord. 2004-01 § 1, 2004; Ord. 2013-04 (Exh. A), 2013; Ord. 2014-01 § 1 (Exh. A), 2014)
All properties within the City of Carmel are located within the coastal zone as defined in the California Coastal Act and are subject to the policies, standards and provisions contained in the certified LCP that may apply. Where any standard provided in this chapter conflicts with any other policy or standard contained in the City's General Plan, Zoning Code or other City-adopted plan, resolution or ordinance not included in the certified Carmel LCP, and it is not possible for the development to comply with both the Carmel LCP and other plans, resolutions or ordinances, the policies, standards or provisions of the LCP shall take precedence consistent with the hierarchy established in CMC § 17.02.090.
(Ord. 2004-02 § 1, 2004; Ord. 2004-01 § 1, 2004; Ord. 2013-04 (Exh. A), 2013; Ord. 2014-01 § 1 (Exh. A), 2014)
A. 
For all projects requiring implementation of an erosion and drainage control plan (subsection (A)(1) of this section), water quality mitigation plan (subsection (D) of this section), or stormwater management plan, the following information shall be submitted with an application for a coastal development permit according to the requirements listed below.
1. 
Construction Phase Requirements – Erosion and Drainage Control Plan. All development permit applications involving alterations to existing buildings or site design, or construction of new buildings that meet the criteria below shall include a site-specific erosion and drainage control plan. Plans shall be required for new development that (a) increases site coverage by more than five percent of the site area, or (b) involves grading that will affect drainage patterns on or off the site, or (c) involves either a rebuild or construction of a new building. The erosion and drainage control plan shall include a site specific erosion control plan that includes controls on grading (i.e., timing and amounts), best management practice for staging, storage, and disposal of construction materials, design specification of sedimentation basins and landscaping/revegetation of graded or disturbed areas. The plans shall also include as site specific polluted runoff control plan that demonstrates how runoff will be diverted from impermeable surfaces into permeable areas of the property in a nonerosive manner and filter and infiltrate stormwater prior to conveyance off-site.
2. 
Post-Construction Phase Requirements – Site Design and Source Control Measures. Post-construction plans detailing how stormwater and polluted runoff will be managed or mitigated should be included in the design of all projects that require an erosion and drainage control plan (subsection (A)(1) of this section). Project submittals shall include details regarding how the project will use appropriate site design and source control BMPs to minimize adverse effects of the project on water quality.
3. 
Water Quality Mitigation Plan. For development which does not mitigate impacts to water quality using site design and source control measures and for certain special categories of development (see subsection (E) of this section) a water quality mitigation plan will be required showing how treatment control (or structural) BMPs will be used (in addition to site design and source control BMPs) to minimize the discharge of polluted runoff from the project.
B. 
All development that requires an erosion and drainage control plan shall require the implementation of appropriate site design and source control BMPs from subsection (D) of this section and Section 3.0 of the City's LID Guidance Manual in Appendix I[1] to this chapter to minimize post-construction polluted runoff. The project plans submitted with the permit application should also specify any treatment control or structural BMPs that the applicant elects to include in the development to minimize post-construction polluted runoff, and include the operation and maintenance plans for these BMPs.
[1]
Editor's Note: Said Appendix I is included as an attachment to this title.
C. 
Less Than Significant Impacts. The following land uses and projects are generally presumed to have a less than significant project-specific water quality impact. These include redevelopment projects that reduce the amount of impervious surfaces on the site, do not change the land use or potential pollutants and are not one of the categories of development requiring a WQMP; and new development and redevelopment projects that incorporate into the project design construction BMPs for erosion, sediment and construction waste control and incorporate post-construction BMPs to protect sensitive riparian or wetland resources, reduce the quantity of runoff, and treat runoff generated by the project to pre-project levels.
D. 
Post-Construction Phase Requirements – Water Quality Mitigation Plan. Plans detailing how stormwater and polluted runoff will be managed or mitigated will be required for all projects that require an erosion and drainage control plan. The basic design elements for all projects (see subsection (B) of this section) will demonstrate how the project will use appropriate site design and source control BMPs to minimize adverse effects of the project on water quality. For certain categories of development a water quality mitigation plan will be required showing how treatment control (or structural) BMPs will be used (in addition to site design and source control BMPs) to minimize the discharge of polluted runoff from the project.
A water quality mitigation plan (WQMP) shall be required for all development that requires an erosion and drainage control plan and either fails to address water quality impact using site design and source control measures or is in a category of development identified below. In addition to the site design and source control BMPs required for a stormwater management plan, the WQMP shall include treatment control (or structural) BMPs identified in Section 4.0 of the City's LID Guidance Manual in Appendix I to this chapter to minimize post-construction polluted runoff. The WQMP shall also include the operation and maintenance plans for these BMPs.
E. 
Special Categories of Development. A WQMP shall be required for projects that fall into one or more of the following categories of development and are not able to meet the appropriate treatment controls for the specific pollutants associated with those development types as set forth in the City's LID Guidance Manual in Appendix I to this chapter as part of the design:
1. 
Industrial/commercial development;
2. 
Restaurants;
3. 
Retail gasoline outlets/automotive service facilities;
4. 
Parking lots (5,000 square feet or more of impervious surface area or with 25 or more parking spaces)/outdoor storage areas;
5. 
Projects that discharge to an environmentally sensitive area (ESA) or coastal water. Such projects are defined as being all development and redevelopment located within or directly adjacent to or discharging directly to an environmentally sensitive area (where discharges from the development or redevelopment will enter receiving waters within the environmentally sensitive area). "Directly adjacent" means situated within 200 feet of the environmentally sensitive area. "Discharging directly to" means outflow from a drainage conveyance system that is composed entirely of flows from the subject development or redevelopment site, and not commingled with flows from adjacent lands.
F. 
CEQA. Provisions of this section shall be complementary to, and shall not replace, any applicable requirements for stormwater mitigation required under the California Environmental Quality Act or Chapter 17.42 CMC.
(Ord. 2004-02 § 1, 2004; Ord. 2004-01 § 1, 2004; Ord. 2013-04 (Exh. A), 2013; Ord. 2014-01 § 1 (Exh. A), 2014)
All applicants shall provide verification of maintenance provisions for structural and treatment control BMPs, including but not limited to legal agreements, covenants, CEQA mitigation requirements, and conditional use permits. Verification at a minimum shall include:
A. 
The developer's signed statement accepting responsibility for maintenance until the responsibility is legally transferred; and either
B. 
A signed statement from the public entity assuming responsibility for structural and treatment control BMP maintenance and that it meets all local agency design standards; or
C. 
Written conditions in the sales or lease agreement, which require the recipient to assume responsibility for maintenance and conduct a maintenance inspection at least once a year; or
D. 
Written text in project conditions, covenants, and restrictions (CCRs) for residential properties assigning maintenance responsibilities to the homeowners association for maintenance of the structural and treatment control BMPs; or
E. 
Any other legally enforceable agreement that assigns responsibility for the maintenance of post-construction structural and treatment control BMPs.
(Ord. 2004-02 § 1, 2004; Ord. 2004-01 § 1, 2004; Ord. 2013-04 (Exh. A), 2013; Ord. 2014-01 § 1 (Exh. A), 2014)
A water quality checklist will be developed by the City and used to supplement the CEQA checklist in the permit review process to assess potential water quality impacts and appropriate mitigation measures.
(Ord. 2004-02 § 1, 2004; Ord. 2004-01 § 1, 2004; Ord. 2013-04 (Exh. A), 2013; Ord. 2014-01 § 1 (Exh. A), 2014)
A. 
BMP Requirements and Implementation. All development shall be evaluated for potential adverse impacts to water quality and the applicant shall consider site design, source control and treatment control BMPs in order to minimize polluted runoff and water quality impacts resulting from the development. A SWMP requires the implementation of site design and source control BMPs, as specified in CMC § 17.43.030(B), and a WQMP requires the implementation of site design, source control and treatment control BMPs, as specified in CMC § 17.43.030(C). In order to maximize the reduction of water quality impacts, BMPs should be incorporated into the project design in the following progression: (1) site design BMPs, (2) source control BMPs, and (3) treatment control BMPs. Examples of these BMPs can be found in the City's LID Guidance Manual in Appendix I[1] to this chapter.
[1]
Editor's Note: Said Appendix I is included as an attachment to this title.
B. 
BMP Selection Process. In selecting BMPs to incorporate into the project design, the applicant should first identify the pollutants of concern that are anticipated to be generated as a result of the development. The City's LID Guidance Manual in Appendix I to this chapter should be used as a guide in identifying these pollutants of concern. Pollutants generated by the development that exhibit one or more of the following characteristics shall be considered primary pollutants of concern:
1. 
Current loadings or historical deposits of the pollutant are impairing the beneficial uses of a receiving water.
2. 
Elevated levels of the pollutant are found in water or sediments of a receiving water and/or have the potential to be toxic to or bioaccumulate in organisms therein.
3. 
Inputs of the pollutant are at a level high enough to be considered potentially toxic.
Site design and source control BMPs are required based on pollutants commonly associated with the project type, as identified in Tables 1 and 2 of Attachment 3 of the City's LID Guidance Manual in Appendix I[2] to this chapter. BMPs that minimize the identified pollutants of concern may be selected from the examples in Table 3 of Attachment 3 of the City's LID Guidance Manual in Appendix I to this chapter and CMC § 17.43.070, targeting primary pollutants of concern first. In the event that the implementation of a BMP listed in the City's LID Guidance Manual in Appendix I to this chapter or CMC § 17.43.070 is determined to be infeasible at any site, the implementation of other BMPs that will achieve the equivalent reduction of pollutants shall be required.
Treatment control BMPs should be selected using the matrix in Table 3 of Attachment 3 of the City's LID Guidance Manual in Appendix I to this chapter as guidance to determine the removal efficiency of the BMP for the pollutants of concern for that project. Treatment control BMPs that maximize pollutant removal for the identified primary pollutants of concern should receive priority for BMP selection, followed by BMPs that maximize pollutant removal for all other pollutants of concern identified for the project. The most effective combination of BMPs for polluted runoff control that results in the most efficient reduction of pollutants shall be implemented. The applicant may select from the list of BMPs in the City's LID Guidance Manual in Appendix I to this chapter. In the event that the implementation of a BMP listed in the City's LID Guidance Manual in Appendix I to this chapter is determined to be infeasible at any site, the implementation of other BMPs that will achieve the equivalent reduction of pollutants shall be required.
[2]
Editor's Note: Said Appendix I is included as an attachment to this title.
C. 
Sizing of Treatment Control BMPs. Where post-construction treatment controls are required, the BMPs (or suites of BMPs) shall be designed in accordance with the requirements contained in the City's LID Guidance Manual in Appendix I to this chapter to infiltrate and/or treat the amount of stormwater runoff that will come from the project site, with an appropriate safety factor (i.e., two or greater), for flow-based BMPs.
The term "treatment" includes physical, biological and chemical processes such as filtration, the use of bioswales, detention and retention ponds and adsorption media. The actual type of treatment should be suited to the pollutants generated by the development as indicated in the City's LID Guidance Manual in Appendix I to this chapter.
D. 
Development on Steep Slopes. Specific requirements for development on steep slopes are contained in Section 2.5.2 of the LID Guidance Manual in Appendix I to this chapter.
E. 
Cumulative Impacts. Because of the City's designation under the Phase II NPDES regulations, all discretionary projects (except those that do not result in a physical change to the environment) within the urbanized area whose contributions are cumulatively considerable must implement one or more best management practices to reduce their contribution to the cumulative impact.
(Ord. 2004-02 § 1, 2004; Ord. 2004-01 § 1, 2004; Ord. 2013-04 (Exh. A), 2013; Ord. 2014-01 § 1 (Exh. A), 2014)
A. 
Commercial Development. Commercial development shall be designed to control the runoff of pollutants from structures, parking and loading areas. The following general measures shall be implemented to minimize the impacts of commercial development on water quality. Specific requirements for commercial development are contained in the City's LID Guidance Manual in Appendix I[1] to this chapter.
1. 
Properly Design Loading/Unloading Dock Areas. Loading/unloading dock areas have the potential for material spills to be quickly transported to the stormwater conveyance system.
2. 
Properly Design Repair/Maintenance Bays. Oil and grease, solvents, car battery acid, coolant, and gasoline from repair and maintenance bays can negatively impact stormwater if allowed to come into contact with stormwater runoff.
3. 
Properly Design Vehicle/Equipment Wash Areas. The activity of vehicle/equipment washing/steam cleaning has the potential to contribute metals, oil and grease, solvents, phosphates, and suspended solids to the stormwater conveyance system.
4. 
Properly Design Parking Areas and Parking Lots. Parking areas and parking lots contain pollutants such as heavy metals, oil and grease, and polycyclic aromatic hydrocarbons that are deposited on parking lot surfaces by motor vehicles. These pollutants are directly transported to surface waters. Parking lots may also accumulate oil, grease, and water insoluble hydrocarbons from vehicle drippings and engine system leaks.
[1]
Editor's Note: Said Appendix I is included as an attachment to this title.
B. 
Restaurants. Restaurants shall be designed to minimize runoff of oil and grease, solvents, phosphates, and suspended solids to the storm drain system.
C. 
Gasoline Stations and Automotive Repair Facilities. Gasoline stations and automotive repair facilities shall be designed to minimize runoff of oil and grease, solvents, car battery acid, coolant and gasoline to stormwater system.
D. 
Outdoor Material Storage Areas. Outdoor material storage areas refer to storage areas or storage facilities used solely for the storage of materials. Improper storage of materials outdoors may provide an opportunity for toxic compounds, oil and grease, heavy metals, nutrients, suspended solids, and other pollutants to enter the stormwater conveyance system.
E. 
Trash Storage Areas. A trash storage area refers to an area where a trash receptacle or receptacles are located for use as a repository for solid wastes. Loose trash and debris can be easily transported by the forces of water or wind into nearby storm drain inlets, channels, and/or creeks.
(Ord. 2004-02 § 1, 2004; Ord. 2004-01 § 1, 2004; Ord. 2013-04 (Exh. A), 2013; Ord. 2014-01 § 1 (Exh. A), 2014)
To mitigate the increased runoff rates from single-family residences due to new impervious surfaces, new and remodel projects which need an erosion and drainage control plan shall include design elements which accommodate on-site percolation, retention or collection of stormwater runoff such that the peak runoff rate after development either meets the eighty-fifth percentile storm event criterion or does not exceed predevelopment runoff levels to the maximum extent practicable, and that runoff that will come from the project site meets the applicable requirements contained in the City's LID Guidance Manual in Appendix I to this chapter.[1] BMPs (including those outlined in the California Stormwater Best Management Practice Handbooks) which may achieve this objective fit into these categories:
A. 
Minimizing impervious areas;
B. 
Increase rainfall infiltration;
C. 
Minimize directly connected impervious areas (DCIAs).
(Ord. 2004-02 § 1, 2004; Ord. 2004-01 § 1, 2004; Ord. 2013-04 (Exh. A), 2013; Ord. 2014-01 § 1 (Exh. A), 2014)
[1]
Editor's Note: Appendix I Low Impact Development Guidance Manual, and Appendix J BMP Guidance Series are included as attachments to this title.