The County of Santa Clara - SCC Public Portal

Sec. B11 1/2-1. Purpose and authority of division.

The purpose of this division is to protect surface water quality, comply with federally mandated nonpoint source pollution control measures, comply with the County's Clean Water Program's Storm Water Management Plan and comply with National Pollutant Discharge Elimination System (NPDES) Storm Water Discharge Permits issued to the County. NPDES Storm Water Discharge Permits require the County and any co-permittees to implement control measures and best management practices to reduce pollutants in storm water discharges to the maximum extent practicable. The County Clean Water Program's Storm Water Management Plan (Plan), also known as the Urban Runoff Management Plan, serves as the framework for identification, assignment, and implementation of control measures. The NPDES Permit(s), the Plan, and handbooks of Best-Management Practices (BMPs) are on file with the Development Services Office.

The authority for this chapter is contained in the Health and Safety Code Section 5471, the Water Quality Act of 1987 Section 402(p), and in the NPDES Storm Water Discharge Permit(s) issued to the County.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-2. Definitions.

The following terms are defined for purposes of this division.

Applicant: Any person, firm, corporation, business, or governmental agency that executes the necessary forms to request official approval of a project or a permit in order to carry out construction of a project.

Best Management Practice (BMPs): A structural device or nonstructural practice designed to treat storm water runoff in order to reduce storm water pollution, or designed to prevent storm water pollution.

County: Santa Clara County, in the State of California.

Deemed complete: The date the Planning Office determines that all the required information in a development application has been provided.

Department of Environmental Health: A department of the County.

Department of Planning and Development: A department of the County.

Development: A proposed land use and/or construction project that requires issuance of a land use approval, a building permit, or a grading permit, prior to commencement of construction.

Development Services Office: An office within the Department of Planning and Development that includes the functions of Building Inspection, Land Development Engineering, Surveying, and the Clean Water Program.

Disturbance, or land disturbance: Grading, filling, grubbing, clearing, vegetation removal, building, or demolition.

Existing conditions: Refers to the conditions that exist on a site before the commencement of a land development project and at the time the County approves plans or issues permits for the land development of a site. Where phased development or plan approval occurs (i.e., preliminary grading, road construction and utility installation, etc.), the existing conditions are considered those at the time prior to the time that the first land use approval, building permit or grading permit is issued.

Food service facility: Any business or establishment that prepares food for sale or distribution to the public.

Group 1 Project: Pursuant to the definition in the County's NPDES Municipal Storm Water Discharge Permit, any private or public land development or redevelopment project creating or replacing one acre or more of impervious surface. (Please see Section B11 1/2-17 for effective dates.) The following types of projects are exempt from the Group 1 Project requirements:

(a) Single-family homes that are not part of a larger common plan of development, when the storm drainage is directed to a landscaped or naturally vegetated area;

(b) Sidewalks;

(d) Trails;

(e) Bridge accessories;

(f) Guardrails;

(g) Landscape features;

(h) Interior remodels;

(i) Routine maintenance or repair, including roof or exterior surface replacement, pavement resurfacing, repaving and road pavement structural section rehabilitation within the existing footprint, and any other reconstruction work within a public street or road right-of-way where both sides of that right-of-way are developed.

Group 2A Project: Pursuant to the definition in the County's NPDES Municipal Storm Water Discharge Permit, this is the same as the Group 1 Project definition, except that the size threshold of impervious area for new and significant redevelopment projects is reduced from one acre to 10,000 square feet, and then only if the project is included in one of the following land use categories (Please see Section B11 1/2-17 for effective dates.):

(a) Gas stations;

(b) Auto wrecking yards;

(d) Vehicle or equipment maintenance areas (including washing and repair), outdoor handling or storage of waste or hazardous materials, outdoor manufacturing area(s), outdoor food handling or processing, outdoor animal care, outdoor horticultural activities, and various other industrial and commercial uses where the potential pollutant loading cannot be satisfactorily mitigated through source control and site design practices.

Group 2B Project: Pursuant to the definition in the County's NPDES Municipal Storm Water Discharge Permit, this is the same as the Group 1 Project definition, except that the size threshold of impervious area for new and significant redevelopment projects is reduced from one acre to 10,000 square feet. (Please see Section B11 1/2-17 for effective dates.)

Hazardous material: Any material so designated by state and federal laws or by County ordinance.

Hydromodification: Changes to the storm water runoff characteristics of a watershed caused by changes in land use.

Hydromodification Management Plan BMPs: Any combination of on-site, off-site, and in-stream control measures incorporated into specified development and redevelopment projects in order to reduce peak amounts of storm water runoff flow, so as to not cause an increase in the erosion potential of the receiving watercourse over the pre-project condition, in accordance with the County's NPDES Municipal Storm Water Discharge Permit and the SCVURPPP Hydromodification Management Plan.

Hydromodification Management Plan (HMP): A comprehensive plan to control hydromodification by maintaining the pre-project stream erosion potential for specific types of development projects.

Impervious surface: A surface composed of any material that significantly impedes or prevents the natural infiltration of water into soil. Impervious surfaces include, but are not limited to, rooftops, buildings, streets and roads, parking lots, concrete or asphalt surfaces, compacted base rock, and compacted soils.

Loading dock: The area of a facility intended for the loading and unloading of trucks or other delivery vehicles.

Maximum extent practicable (MEP): The maximum degree of pollution reduction that is achievable by applying best management practices, taking into account the best available technology, cost effectiveness, and other competing issues such as human safety and welfare, endangered species and threatened resources, historic properties and geographic features.

New development: Land development activity on a previously undeveloped site.

NPDES Municipal Storm Water Discharge Permit: A National Pollution Discharge Elimination System (NPDES) Permit issued to the County of Santa Clara and other local jurisdictions by the Regional Water Quality Control Board of the San Francisco Bay Region or of the Central Coast Region, State of California.

Numeric sizing criteria: Equations used for designing storm water treatment measures that are included in the County's NPDES Municipal Storm Water Discharge Permit.

Operation and maintenance agreement: A written agreement providing for the long-term operation and maintenance of storm water management facilities and practices on a site or with respect to a land development project, which when properly recorded with the County Recorder constitutes a restriction on the title to a site.

Owner: The legal or beneficial owner of a site, including but not limited to a person, firm, or corporation in control of the site.

Permit: The permit issued by the County of Santa Clara to an applicant that is required for commencing a land use, land development activity, or a construction project.

Person: Any person, firm, association, organization, partnership, business trust, joint venture, corporation, or company.

Petroleum product: Fuel oil, sludge, oil refuse, oil mixed with waste, gasoline, motor fuel, motor oil, gear oil, and grease.

Planning Office: An office within the Department of Planning and Development.

Program: The County of Santa Clara Clean Water Program

Post-development: Refers to the time period, or the conditions that may reasonably be expected or anticipated to exist, after completion of the land development construction activity on a site.

Redevelopment: A land development project on a previously developed site; excluding ordinary maintenance activities, interior remodeling of existing buildings, resurfacing of paved areas, and exterior changes or improvements which do not materially increase or concentrate storm water runoff, or cause additional storm water runoff pollution.

Refuse: Putrescible and non-putrescible solid or liquid materials or waste, whether combustible or noncombustible, and including garbage, rubbish and food processing waste.

Runoff: Flowing storm water that leaves a site.

Runon: Flowing storm water entering a site from off site.

San Francisco Bay Watershed: All of the territory within Santa Clara County where storm drainage flows to San Francisco Bay.

Santa Clara Valley Urban Runoff Pollution Prevention Program (SCVURPPP): The Santa Clara Valley Urban Runoff Pollution Prevention Program is an association of local jurisdictions located in the northern Santa Clara Valley. SCVURPPP jurisdictions, also referred to as co-permittees, share a common Municipal NPDES Permit to discharge storm water to San Francisco Bay.

Site: Any tract, lot or parcel of land or combination of tracts, lots, or parcels of land, which are under one ownership, or are contiguous and in diverse ownership where a development is to be performed as part of a use permit, subdivision, building permit, or project.

Site design BMPs: Nonstructural techniques designed to reduce the amount of runoff by decreasing the amount of impervious surface, infiltrating runoff into the soil and/or providing storm water detention. Examples of site design BMPs may include narrower streets, permeable pavement, detention ponds, and shared driveways.

Source control BMPs: Structural measures or nonstructural practices used to eliminate contact between rainfall and potential source of contamination. Examples include covered materials handling areas, covered garbage and refuse receptacles, parking lots sweeping, etc.

Storm water discharge: Any flow from land or from impervious surfaces that enters into the storm water system, watercourses, or any other water body.

Storm water treatment measures: Permanent structural measures designed to reduce storm water pollution by capturing and treating runoff. Examples include detention basins, vegetated swales and media filters.

Soil sediments: The soil washed away by water. As used in this division "soil sediments" refers to the loss of soil caused by land disturbance and does not apply to naturally occurring erosion on undisturbed land.

Storm drain: Any inlet, pipe, conduit, swale, channel or creek designed or used for the disposal of storm and surface waters and drainage, but excluding any sanitary sewer system.

Storm water: Unpolluted water that has no added constituents that would render it unacceptable for disposal to storm or natural drainage channels, or directly to surface waters.

Storm water system: The system of inlets, drains, pipes, swales, channels, creeks, which collects, directs and transports storm water runoff.

Unincorporated area: Those portions of the County which lie outside municipal boundaries of the cities within the County.

Watercourse: Any natural or artificial stream, river, creek, ditch, channel, canal, conduit, culvert, drain, waterway, gully, ravine or wash, in and including any adjacent area that is subject to inundation from storm water flow, overflow, or flood water; and any channel, either manmade or natural, in which a flow of water occurs, either continuously or intermittently.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-3. Severability.

If any section, subsection, subdivision, sentence, clause, or phrase of this chapter is for any reason held to be unconstitutional or otherwise void or invalid by any court of competent jurisdiction, the validity of the remaining portion of this chapter shall not be affected thereby

(Ord. No. NS-517.74, § 1, 10-17-06)

CHAPTER II.
DISCHARGES TO STORM WATER SYSTEM

Sec. B11 1/2-4. Discharge prohibition.

It shall be unlawful to discharge, or cause, allow or permit to be discharged into any part of the storm water system or watercourses any sewage, industrial wastes, hazardous waste, anti-freeze, petroleum or petroleum products, coal tar, chemicals, detergents, solvents, paints, contaminated or chlorinated swimming pool water, pesticides, herbicides, fertilizers, soil sediments, wash water, cans, bottles, refuse, animal wastes, cement powder, concrete waste, broken concrete, construction site waste or debris, motor or other vehicles or parts thereof, or any material that may be deleterious to aquatic life.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-5. Exceptions to discharge prohibitions.

The provisions of this division shall not prohibit any discharge in compliance with a valid NPDES Permit issued to the discharger.

(Ord. No. NS-517.74, § 1, 10-17-06)

CHAPTER III.
ENFORCEMENT

Sec. B11 1/2-6. Violation--Misdemeanor.

Any person who intentionally or negligently violates any provision of this division shall be guilty of a misdemeanor and upon conviction shall be punished as provided by Penal Code Section 19 as a separate violation for each day in which the violation occurs or continues. The County's share of any fine collected pursuant to this section shall be deposited into the County Clean Water Program account.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-7. Violation--Civil penalty.

Any person who intentionally or negligently violates any provision of this division or any provision of any permit issued pursuant to this division shall be subject to civil penalties in a sum not less than $1,000.00 or more than $25,000.00 for each day of violation. The civil penalty provided in this section is cumulative and not exclusive, and shall be in addition to all other remedies available to the County under state and federal law and local ordinance. Any civil penalties collected pursuant to this section shall be deposited into the Clean Water Program account.

In determining the penalty, the court shall consider all relevant circumstances, including but not limited to the following:

(a) The extent of harm or potential harm caused by the violation;

(b) The nature and persistence of the violation;

(d) Corrective action, if any, taken by the violator.

In any civil action brought pursuant hereto, in which the County prevails, the court shall determine and impose reasonable expenses, including attorney's fees, incurred by the County in the investigation and prosecution of the action.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-8. Enforcement authority.

Pursuant to Section 836.5 of the California Penal Code, the Director of Planning and Development, the Manager of the Development Services Office, the Director of Environmental Health, or their designees are hereby authorized to enforce the provisions of this division and to issue citations for violations thereof.

Whenever necessary for the purpose of determining compliance or enforcing the provisions of this division, or whenever any enforcement officer has reasonable cause to believe that there exists in any structure or upon any premises any condition which constitutes a violation of this division, the officers may enter the structure or premises at all reasonable times to inspect, or to perform any duty imposed upon any of the officers by law; provided that if the structure or premises is occupied, the officer shall first present proper credentials and request entry, and further provided, that if the structure or premises is unoccupied, the officer shall first make a reasonable attempt to contact a responsible person from the firm or corporation and request entry, except in emergency circumstances. If entry is refused, the officer seeking entry will have recourse to every remedy provided by law to secure entry.

There will be no civil liability on the part of, and no cause of action will arise against, any enforcement officer acting pursuant to this section and within the scope of authority. Furthermore, nothing in this division may be construed to hold the County or any officer, employee or representative of the County responsible for any damage to persons or property by reason of making an inadequate or negligent inspection or by reason of any failure to make an inspection or reinspection or by reason of any failure to take any enforcement or remedial action.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-9. Investigation.

The Director of the Department of Planning and Development, or designee, may make such investigations of storm drainage facility conditions, illicit connections to the storm drainage system, illegal dumping to the storm drainage system, and of potential or actual sources of storm water pollution deemed necessary to carry out the purposes of this division.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-10. Enforcement cost recovery.

(a) A property owner must reimburse the Department of Planning and Development for actual costs incurred by the Department for any activities necessary to enforce this Division.

(b) Upon completion of enforcement activities, the Director of Planning and Development will provide an invoice for these enforcement costs indicating the total hours expended, the basis for the expenditure, and the hourly cost rate of the Department.

(c) Charges for enforcement costs invoiced by the Department of Planning and Development pursuant to this section will be based on hourly rate in an amount established by resolution of the Board of Supervisors.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-11. Violations deemed a public nuisance.

Any condition caused or permitted to exist in violation of any of the provisions of this division is a threat to public health, safety and welfare, and is declared to be a public nuisance and may be abated as such.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-12. Remedies not exclusive.

Remedies in this division are in addition to and do not supersede or limit any and all other remedies, civil, criminal or administrative.

(Ord. No. NS-517.74, § 1, 10-17-06)

CHAPTER IV.
STORM WATER POLLUTION PREVENTION REQUIREMENTS FOR CONSTRUCTION ACTIVITY

Sec. B11 1/2-13. State of California General NPDES Permit for Storm Water Discharges Associated with Construction Activity.

Applicants for projects that disturb a land area of one acre or more shall submit a signed certification prior to building permit and/or grading permit issuance that they have complied, or will comply prior to commencement of construction, with the requirements of the State of California General NPDES Permit for Storm Water Discharges Associated with Construction Activity.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-14. Construction Site Best Management Practices (BMPs).

All construction sites shall be maintained in accordance with the following requirements:

(a) Garbage, trash, and refuse shall be stored in a covered receptacle and then removed to a sanitary landfill. Piles or stacks of wood waste, hardened concrete, hardened plaster, dried paint, and concrete demolition rubble are exempt from this storage receptacle requirement. Materials that are exempt from the covered receptacle requirement must be covered with waterproof tarps during the rainy season, until disposed of at a sanitary landfill.

(b) A lined pit or basin shall be provided for concrete, plaster, and wallboard compound washout, in order for it dry to solid matter. When these materials have dried and hardened, they shall be disposed of in the trash receptacle.

(c) Hazardous materials shall be stored as required by the Santa Clara County Ordinance Code, Division B11, Chapters XIII, XIV, and XV.

(d) Nearby storm drain inlets shall be protected by appropriate BMPs, such as filter fabric, rock filled filter bags, sand bags and proprietary filtration devices.

(e) Erosion prevention and sediment control measures shall be followed as required by the Santa Clara County Ordinance Code, Division C12, Chapter III, consistent with the measures outlined on the approved building and/or grading plans.

(f) Temporary sedimentation basins or sedimentation tanks or similar measures are required to settle and/or filter turbid or muddy discharges of pumped groundwater or surface water flowing from construction sites.

(Ord. No. NS-517.74, § 1, 10-17-06)

CHAPTER V.
STORM WATER POLLUTION PREVENTION REQUIREMENTS FOR THE SAN FRANCISCO BAY WATERSHED

Sec. B11 1/2-15. Purpose of chapter.

The purpose of this chapter is to provide minimum requirements designed to control, reduce, and prevent the discharge of pollutants into the storm water system of Santa Clara County from public and private land development projects, in compliance with applicable provisions of the Federal Clean Water Act and any National Pollutant Discharge Elimination System (NPDES) Storm Water Discharge Permits issued to the County of Santa Clara. This chapter only applies to properties located within the unincorporated area and also within the watershed of the San Francisco Bay and that meet the criteria stated herein.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-16. Project criteria.

Projects are determined to be Group 1, Group HMP, Group 2A, or Group 2B development or redevelopment projects by their size and the date deemed complete. (See Watershed Map, on file with the Development Services Office)

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-17. Permanent storm water pollution prevention measures required for certain development projects located within the San Francisco Bay Watershed.

A. Site Design and Source Control BMP Requirements. The projects shall include, where practicable as determined by the Development Services Office, appropriate site design and source control BMPs in order to reduce the water quality impacts of storm water runoff from the site, for the life of the project.

B. Requirements and Effective Dates for Storm Water Treatment BMPs.

1. In addition to site design and source control BMPs, Group 1, Group 2A, and Group 2B project applicants are required to design and implement permanent storm water treatment measures sufficient to reduce the water quality impacts of storm water runoff from the site for the life of the project.

2. Any Group 1 defined project for which a land use application to the County was deemed complete by the Planning Office prior to October 15, 2003, is not required to implement storm water treatment measures.

3. Any Group 2A defined project for which an application to the County was deemed complete by the Planning Office prior to October 20, 2005 is not required to implement storm water treatment measures. Group 2A is superseded by Group 2B effective August 15, 2006.

4. Any Group 2B defined project for which an application to the County was deemed complete by the Planning Office prior to August 15, 2006 is not required to implement storm water treatment measures.

5. When a project application or building permit has expired, even when previously deemed complete, any re-application or new application must conform to the provisions of this ordinance that are in effect at the time of re-application. This section shall not apply to applications that are extended under the provisions of a county ordinance, prior to the land use application expiration date.

C. Hydromodification Management Plan (HMP) BMP Requirements and Exemptions.

1. In accordance with the County's NPDES Municipal Storm water Discharge Permit, all Group 1 Projects are required to implement permanent Hydromodification Management BMPs, except for the following projects:

a. Projects that do not create an increase in impervious surface over pre-project conditions.

b. Transit-oriented developments located within a one-half mile radius of existing or planned transit stations and/or major transfer points.

c. Projects located in sub-watershed areas that are 90 percent or more built-out relative to zoning and have more than 65 percent impervious surface. (Please see red colored area on HMP Map, on file with the Developments Services Office.)

d. Projects that are less than 50 acres in total project size that are located in sub-watershed areas that are 90 percent or more built-out relative to zoning and have less than 65 percent impervious surface. (Please see yellow colored area on HMP Map, on file with the Developments Services Office.)

e. Projects located within areas that drain to stream channels within the tidally influenced area, projects located within areas that drain to non-earthen stream channels that are hardened on three sides and extend continuously upstream from the tidally influenced area, and projects draining to an underground storm drain that discharges directly to San Francisco Bay. (Please see purple colored area on HMP Map, on file with the Developments Services Office.)

f. Projects that demonstrate, through stream-specific modeling studies consistent with the HMP that there will be no increase in erosion potential or other adverse impact to the beneficial uses to any waters of the State of California.

2. HMP projects that are located on sites less than or equal to 20 acres in size (small site projects) that are not part of a larger phased development shall comply with the HMP requirements through the use of appropriate site design, source control, and treatment control measures with flow control benefits to the maximum extent practicable. In addition, where available, off-site and/or in-stream controls should be considered in meeting the management standard.

To demonstrate compliance with the maximum extent practicable criterion, small site projects may use small-scale, distributed storm water management techniques such as bio-retention facilities, infiltration trenches, filter strips, vegetated swales, and multi-functional landscape areas to achieve treatment and flow reduction. Runoff volume reduction and time of concentrations for small-scale facilities can be computed using a discrete storm event approach until other simplified tools based on continuous simulation modeling are available for sizing flow control BMPs. Small site projects may demonstrate that this performance criterion is being met by matching pre- and post-project runoff volume and time of concentration (based on the two- and ten-year storms) to the maximum extent practicable.

3. Determination of impracticability. Meeting the HMP requirements will be considered impracticable if the combined construction cost of both required storm water treatment and hydromodification management BMPs exceeds two percent of the project construction cost, excluding land costs, soil disposal fees, hauling, contaminated soil testing, mitigation, disposal, or other normal site enhancement costs such as landscaping or grading that are required for other development purposes.

If a developer demonstrates that the total cost to fully comply with the HMP and other storm water treatment requirements will exceed this cost threshold, a determination may be made by Manager of the Development Services Office or designee that the project shall comply with the HMP requirements by either (1) implementing hydromodification management controls on-site to the maximum extent practicable, or (2) by contributing to an in-stream or off-site solution, if available, up to a maximum cost for all controls of two percent of the project cost. (The in-stream or off-site solution may be located within another jurisdiction or on land controlled by the Santa Clara Valley Water District.)

D. Group 1, Group 2A, and Group 2B projects that result in an increase of, or replacement of, more than 50 percent of the impervious surface of a previously existing development shall include permanent BMPs sufficient to reduce water quality impacts of storm water runoff from the entire site for the life of the project. These permanent BMPs should include site design, source control, storm water treatment measures, and if applicable, hydromodification management measures.

E. Group 1, Group 2A, and Group 2B projects that result in an increase of, or replacement of fifty (50) percent or less of the impervious surface of a previously existing development shall include permanent BMPs sufficient to reduce water quality impacts to storm water runoff from the increased or replaced portion of the site, for the life of the project. These permanent BMPs should include site design, source control, storm water treatment measures, and if applicable, hydromodification management measures.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-18. Design and Selection of Best Management Practices.

A. Storm water quality best management practices shall be selected and designed to the satisfaction of the Manager of the Development Services Office or designee in accordance with the requirements contained in the most recent versions of the following documents:

1. NPDES Municipal Storm Water Discharge Permit issued to the County of Santa Clara by the San Francisco Bay Regional Water Quality Control Board;

2. Santa Clara Valley Urban Runoff Pollution Prevention Program (SCVURPPP.) "Guidance for Implementing Storm Water Regulations for New and Redevelopment Projects";

3. California BMP Handbooks developed by the California Storm Water Quality Agencies Association (CASQA);

4. "Start at the Source" Design Guidance Manual developed by the Bay Area Storm Water Management Agencies Association (BASMAA) ;

5. Bay Area Storm water Management Agencies Association "Using Site Design Standards to Meet Development Standards for Storm Water Quality - A Companion Document to Start at the Source"; and

6. The SCVURPPP Hydromodification Management Plan, as approved by the San Francisco Bay Regional Water Quality Control Board.

B. Numeric sizing criteria used to design storm water treatment systems shall be in accordance with the County's NPDES Municipal Storm Water Discharge Permit.

1. Storm water treatment measures depending on volume capacity, such as detention/retention units or infiltration structures, shall be designed to treat storm water runoff equal to:

a. The maximized storm water quality capture volume for the area, based on historical rainfall records, determined using the formula and volume capture coefficients set forth in Urban Runoff Quality Management, WEF Manual of Practice No. 23/ASCE Manual of Practice No. 87, (1998), pages 175-178 (e.g. approximately the 85th percentile 24-hour storm runoff event); or

b. The volume of annual runoff required to achieve 80 percent or more capture, determined in accordance with the methodology set forth in Appendix D of the California Storm water Best Management Practices Handbook for New Development and Redevelopment (2003), using local rainfall data.

2. Storm water treatment measures whose primary mode of action depends on flow capacity, such as swales, sand filters, or wetlands, shall be sized to treat:

a. Ten percent of the 50-year peak flow rate; or

b. The flow of runoff produced by rain equal to at least two times the 85th percentile hourly rainfall intensity for the applicable area, based on historical records of hourly rainfall; or

c. The flow of runoff resulting from rain equal to at least 0.2 inches per hour intensity.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-19. Storm water treatment questionnaire required for Group 1, Group 2A, and Group 2B Project Applications.

A. Initial land use permit or building permit application requirements. Applications for Group 1, Group 2A, or Group 2B projects shall be accompanied by a Storm Water Treatment Questionnaire. The Questionnaire is available from the Department of Planning and Development.

B. Questionnaire information. The storm water treatment questionnaire shall include the following information:

1. Project name (if any), common address, parcel number of the site, building permit application plan check number, County land use application file number, applicant's name (include all persons having an interest in the property).

2. Whether the project is a subdivision, multi-family residential, commercial, industrial, or a governmental project.

3. Data for total site area, total disturbed area, existing impervious area, proposed new and/or replacement impervious surface area, total impervious surface area, and percent of increase of new or replacement impervious area.

4. The type of pesticide use reduction strategy to be utilized.

5. The general type of proposed storm water treatment measures, proposed site design measures, and proposed source control measures to be utilized.

6. A list of any other applicable water quality related permits, if any, that will be required for the project and the permitting agencies (examples: Santa Clara Valley Water District Permit, State Department of Fish and Game Stream Alteration Agreement, Regional Water Quality Control Board Water Quality Certification, Army Corps of Engineers Water Quality Certification, etc.).

7. A listing of existing or proposed water related resources at the site, including watercourses, streams, wetlands, springs, seeps, water wells, impoundments, on-site sewage disposal systems, etc.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-20. Storm water treatment design information to be included with final building and/or final grading plan submittals.

A. For projects where storm water treatment and/or H.M.P measures are required, the following items shall be submitted for plan checking prior to issuance of building permits and/or grading permits:

1. Hydrologic computations, including drainage area maps depicting existing and post-development runoff flow paths and land use.

2. Hydraulic computations for existing and post-development conditions.

3. If a grading permit is involved, an erosion prevention and sediment control plan must be submitted, as required by the County Grading Ordinance, County Ordinance Code, Division C12, Chapter III.

4. Structural and construction details for all components of the proposed drainage system or systems and storm water management facilities.

5. If landscaping is required, submit a landscaping plan showing disposition of existing vegetation and any vegetative site stabilization and/or landscape-based storm water management measures.

6. Cost estimates for all proposed on-site storm water treatment facilities.

7. Recommended BMP operation and maintenance procedures, including maintenance tasks, inspection and maintenance schedule, the parties responsible for BMP operation and maintenance, funding mechanisms for on-going operation, maintenance, access and safety issues.

B. HMP-Related Requirements. The following information must be included for any Group 1 project that is also subject to HMP requirements.

1. A statement of the particular reasons for the applicability of the HMP requirements to the specific project.

2. Hydrologic and hydraulic calculations for any hydromodification management BMPs, including an explanation of how these BMPs will function as the required flow controls.

3. If the applicant is applying for an exemption from HMP requirements, hydraulic calculations and construction cost data must be submitted in order to justify the requested exemption.

4. This information shall be prepared, signed, and stamped by a private professional civil engineer who is registered by the State of California.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-21. Preparation and submittal of storm water treatment, pesticide reduction, and HMP certifications.

A. Group 1, Group 2A, and Group 2B project storm water treatment designs. Design certifications and calculations shall be prepared and submitted for any Group 1, Group 2A, or Group 2B project for plan checking prior to building or grading permit issuance, and shall be prepared by a private professional civil engineer who is registered by the State of California. The certification will verify whether the design meets the requirements of the County's NPDES Permit with regard to storm water treatment. The professional civil engineer shall submit the original signed and stamped certification form.

B. Group 1, Group 2A, and Group 2B project pesticide reduction landscape designs. Design certifications and a list of species proposed shall be prepared and submitted for any Group 1, Group 2A, or Group 2B project for plan checking prior to building or grading permit approval, and shall be prepared by a licensed landscape architect who is registered by the State of California. The certification will verify whether the landscape design meets the intent of the County's NPDES Permit with regard to reducing pesticide needs. The licensed landscape architect shall submit the original signed and stamped certification form.

C. HMP project certifications. Design certifications and calculations for group 1 projects that are also HMP projects shall be prepared and submitted by a private professional civil engineer who is registered by the State of California. The certification will verify whether the design meets the requirements of the SCVURPPP Hydrograph Modification Plan requirements. The professional civil engineer shall submit shall submit the original signed and stamped certification form.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-22. Operation and maintenance responsibility for storm water treatment and HMP measures.

A. For the life of the project, all on-site storm water management facilities shall be operated and maintained in good condition and promptly repaired by the property owner(s), a Homeowners' Association, or other legal entity approved by the County.

B. Any repairs or restoration and maintenance shall be in accordance with the original County- approved plans.

C. The property owner(s) of Group 1, Group 2A, and Group 2B projects shall at the minimum follow the inspection schedule specified in Section B11 1/2-24.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-23. Storm water treatment measures operation and maintenance agreement for Group 1 (including Group 1 HMP Projects), Group 2A, and Group 2B projects.

A. Prior to the issuance of any building or grading permit for a Group 1 (including Group 1 HMP Projects), Group 2A, or Group 2B project, the owner(s) of the site shall enter into a formal written storm water BMP operation and maintenance agreement with the County. The County shall record this agreement with reference to the property or properties involved with the Clerk-Recorder of the County of Santa Clara, and it shall be binding on all subsequent owners of land served by the required storm water treatment BMPs.

B. The storm water BMP operation and maintenance agreement shall require that the BMPs not be modified without the permission of the Development Services Office of the County Department of Planning and Development, and that BMP maintenance activities not alter the design or function of the facility from the original approved plan, unless approved by the Development Services Office prior to the commencement of the proposed modification or maintenance activity.

C. Prior to building or grading permit issuance, the owner shall provide the Development Services Office with a signed and notarized recordable copy of the storm water BMP operation and maintenance agreement and payment in the amount of the recording fee .

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-24. Storm water treatment measures inspection responsibility.

A. The property owner(s) of Group 1 (including Group 1 HMP projects), Group 2A, and Group 2B projects shall be responsible for having all storm water management facilities periodically inspected for condition and function by a privately employed professional civil engineer who is registered by the State of California. (Alternatively, maintenance of landscape-based storm water treatment designs may also be inspected by a landscape architect who is licensed by the State of California.)

B. Unless otherwise required by the Development Services Office, storm water facility inspections shall be inspected according to the following schedule:

1. Landscape based facilities: once every three years (i.e., vegetated swales).

2. Detention based facilities: once every two years (i.e., detention ponds).

3. Growing (or green) roof systems: once every year (i.e., roofs that are covered with vegetation designed to trap storm water pollutants).

4. Proprietary devices, installed either underground or at the surface, that use filtration, baffles, chambers, or inverts to trap sediment: once every year (i.e., concrete chambers or flow devices designed for storm water treatment).

5. Infiltration based devices: once every three years (i.e. shallow rock filled dry wells, infiltration trenches, or pervious pavement).

6. Devices that use multiple methods of storm water treatment: once every year (i.e. a combination of a detention pond and an infiltration trench).

7. Devices that utilize powered pumping equipment: once every six months (i.e. any storm water treatment device where the discharge is higher than the inlet, requiring the pumping to a higher elevation of the treated storm water discharge).

C. Written records shall be kept of all inspections and shall include, at minimum, the following information:

1. Site address.

2. Date and time of inspection.

3. Name and signature of the person conducting the inspection.

4. Name, signature, and stamp of the privately employed professional civil engineer, or landscape architect for landscape-based designs, who is registered by the State of California, and who is responsible for the inspection.

5. List of storm water facilities inspected.

6. Condition of each storm water facility inspected.

7. Description of any needed maintenance or repairs.

8. As applicable, the need for site re-inspection prior to the next routine inspection.

9. Any noted violations of this ordinance or of the NPDES Storm Water Discharge Permit.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-25. Records of maintenance and inspection activities.

On or before May 15th of each year, the party responsible for the operation and maintenance of on-site storm water management facilities of Group 1 (including Group 1 HMP Projects), Group 2A, and Group 2B projects shall provide the Development Services Office with records of all inspections, maintenance and repairs for the just completed rainy season (October 15th through April 15th).

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-26. Failure to maintain storm water treatment and HMP facilities.

If the property owner fails or refuses to meet the requirements of the storm water BMP operation and maintenance agreement, the County, after 30 days' written notice, may correct a violation of the design standards or maintenance requirements by performing the necessary work to place the facility or practice in proper working condition. The County will invoice the owner(s) of the property for the cost of repair work and any administrative costs, pursuant to Section B11 1/2-10.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-27. Approved storm water pollutant source control BMPs.

A. Storm drain inlet labeling. Storm drain inlets for all Group 1, Group 2A, and Group 2B projects shall be clearly marked with the words "No Dumping - Flows to Bay," or the equivalent.

B. Waste plumbing drains and other drains.

1. Interior floor drains shall not be directly or indirectly connected to the storm drainage system.

2. Exterior drains within the following areas shall not be connected to the storm drain (Provide vermin proof grate or screen, and gas tight cap for external drains):

a. Equipment or vehicle washing areas.

b. Areas where chemicals, hazardous materials, or other uncontained materials are stored, unless secondary containment is provided.

c. Equipment or vehicle fueling areas or fluid changing areas.

d. Loading docks where chemicals, hazardous materials, grease, oil, or waste products are handled.

3. Roof runoff shall be directed first to landscaped areas or naturally vegetated areas, unless deemed infeasible by the Manager of the Development Services Office or a designee. Appropriate energy dissipation shall be provided.

4. Nonresidential facilities shall either: (a) provide secondary containment for all roof-mounted equipment, tanks, and piping containing liquids other than potable water; or (b) connect all covered equipment roof drains and equipment discharge lines to the sanitary sewer, with an appropriate backflow prevention device or air gap separation.

5. Boiler drain plumbing lines shall be connected to the sanitary sewer system with an appropriate backflow prevention device or air gap separation, and may not be discharged to the storm drainage system.

6. Cooling systems shall not be connected to or allowed to drain to the storm drainage system.

7. Cooling system condensate lines shall not be connected to or allowed to drain directly to the storm drainage system. The first choice discharge shall be the sanitary sewer with an appropriate backflow prevention device or air gap separation, and the second choice for discharge shall be to a landscaped or naturally vegetated area if the first choice is not practicable.

C. Swimming pool and spa discharges.

1. It shall be unlawful to discharge water from pools, hot tubs, and spas to the storm drainage system.

2. When draining a pool, a hose or other temporary system shall be directed into a sanitary sewer clean out. To prevent a cross connection from occurring, an air gap of two times the receiving sewer pipe diameter shall be provided.

3. For swimming pools located on premises where a sanitary sewer connection exists, a sewer clean out shall be installed in a readily accessible area. Such a cleanout shall not be provided when the site is served by an on-site sewage disposal system.

4. During periods without rainfall, swimming pool and spa discharges may be directed to landscaped areas for percolation and/or evaporation, provided this does not generate runoff to the storm drainage system and does not cause a nuisance to adjacent property owners or neighbors.

D. Vehicle and equipment fueling facilities. Vehicle or equipment fueling facilities shall be designed to prevent the run-on of storm water and runoff of spills. This shall be accomplished by:

1. Paving the fueling area with concrete or other impervious surface.

2. Covering the fueling area and the fuel pumps.

3. Grading the area (i.e., sloping inwardly) or installing a berm or curb around the perimeter of the fueling area. Storm drains shall be prohibited within these fueling areas, unless they drain to a permitted oil/water separator device.

E. Garbage and refuse receptacles serving food service facilities.

1. New food service facilities shall have a sink or other area for cleaning floor mats, containers, and equipment, which is connected to a grease removal device and thence to the sanitary sewer or an approved on-site sewage disposal system. The sink or cleaning area shall be large enough to clean the largest mat or piece of equipment to be cleaned.

2. New buildings constructed to house food service facilities shall include a covered area for a dumpster. The area shall be designed with slope or berms to prevent storm water run-on to the area and storm water runoff from the area.

3. Drains that are installed beneath covered dumpsters serving food service facilities must be connected to a the sanitary sewer or an approved on-site sewage disposal system.

F. Garbage and refuse receptacles. ("dumpsters") serving residences.

1. New residential buildings and all commercial and industrial buildings, except for single-family, duplex, and triplex residences, shall provide a covered-area for a dumpster.

2. The dumpster storage area shall be designed to prevent both storm water runon and storm water runoff under the cover.

3. Any drains that are installed beneath covered dumpsters must be connected to the sanitary sewer or an approved on-site sewage disposal system.

(Ord. No. NS-517.74, § 1, 10-17-06)

Sec. B11 1/2-28. Approved storm water pollutant site design BMPs.

A. Minimize land disturbance.

B. Minimize impervious surfaces.

C. Minimize the impact of parking lots, including parking space maximization within a given area, use of landscaping as a storm water treatment feature, and give consideration to the use of pervious pavement, etc.

D. Cluster structures and pavement to preserve open space and/or vegetated areas.

E. Connect roof downspouts to splash blocks or "bubble-ups", and conduct storm water to vegetated or landscaped areas, instead of directly to the street gutter or storm drain.

F. Installation of micro-detention areas, including landscape detention and the use of cisterns or dry wells for infiltration, where conditions allow.

G. Preserving open space.

H. Maintaining and/or restoring riparian areas and wetlands as project amenities, including establishing vegetated buffer zones to reduce runoff into waterways, allow for potential stream channel changes, and other mitigations.

I. Incorporating supplemental controls to minimize changes in the volume, flow rate, timing, and duration of runoff, for a given precipitation event or events. These changes may include mitigating the cumulative hydromodification caused by site development. Measures may include landscape-based measures or other features to reduce the runoff velocity, increase runoff detention, and/or increase runoff infiltration.

(Ord. No. NS-517.74, § 1, 10-17-06)