Article 15 — Model Ordinance for Post-Development Stormwater Management for New Development and Redevelopment

The purpose of this ordinance is to protect, maintain and enhance the public health, safety, environment and general welfare by establishing minimum requirements and procedures to control the adverse effects of increased post-development stormwater runoff and nonpoint source pollution associated with new development and redevelopment. It has been determined that proper management of post-development stormwater runoff will minimize damage to public and private property and infrastructure, safeguard the public health, safety, environment and general welfare of the public, and protect water and aquatic resources.

This ordinance seeks to meet that purpose through the following objectives:

or,

The Director of the City of Lawrenceville Department of Planning and Zoning or his or her designee is hereby appointed to administer and implement the provisions of this ordinance.

This ordinance is not intended to modify or repeal any other ordinance, rule, regulation or other provision of law. The requirements of this ordinance are in addition to the requirements of any other ordinance, rule, regulation or other provision of law, and where any provision of this ordinance imposes restrictions different from those imposed by any other ordinance, rule, regulation or other provision of law, whichever provision is more restrictive or imposes higher protective standards for human health or the environment shall control.

If the provisions of any section, subsection, paragraph, subdivision or clause of this ordinance shall be adjudged invalid by a court of competent jurisdiction, such judgment shall not affect or invalidate the remainder of any section, subsection, paragraph, subdivision or clause of this ordinance.

The City of Lawrenceville will utilize the policy, criteria and information including technical specifications and standards in the City of Lawrenceville Stormwater Design Manual for the proper implementation of the requirements of this ordinance. The City of Lawrenceville Stormwater Design Manual is hereby incorporated into these Development Regulations as if set forth fully herein. The City’s Stormwater Design Manual may be updated and expanded periodically, based on improvements in science, engineering, monitoring and local maintenance experience.

management application and plan for approval.

and banks that conducts continuously or periodically flowing water.

the City of Lawrenceville or other government agency or land trust that permanently protects open space or greenspace on the owner’s land by limiting the amount and type of development that can take place, but continues to leave the remainder of the fee interest in private ownership.

Department of Planning and Zoning.

stormwater management facility for the purpose of controlling the peak discharge.

detention of stormwater runoff and gradual release of stored water at controlled rates.

Planning and Zoning or his or her designee.

tract or parcel of land allowing the owner of adjacent tracts or other persons to discharge stormwater runoff onto the tract or parcel of land subject to the drainage easement.

designed to minimize the accelerated erosion and sediment runoff at a site during land disturbance activities.

extended period, typically twenty-four (24) hours or greater.

impacts from large low-frequency storm events with a return frequency of one hundred (100) years or more.

confined within the banks or walls of a conveyance or stream channel and that overflows onto adjacent lands.

site that are preserved in a natural state.

generate highly contaminated runoff, with concentrations of pollutants in excess of those typically found in stormwater.

Service classification system in which soils are categorized into four runoff potential groups. The groups range from group A soils, with high permeability and little runoff produced, to group D soils, which have low permeability rates and produce much more runoff.

significantly impedes or prevents the natural infiltration of water into soil. Impervious surfaces include, but are not limited to, rooftops, buildings, streets and roads, and any concrete or asphalt surface.

Elimination System (NPDES) permit issued to an industry or group of industries which regulates the pollutant levels associated with industrial stormwater discharges or specifies on-site pollution control strategies.

subsoil.

providing for the long-term inspection and maintenance of stormwater management facilities and practices on a site or with respect to a land development project, which when properly recorded in the deed records constitutes a restriction on the title to a site or other land involved in a land development project.

surface water or groundwater at a frequency and duration sufficient to support a prevalence of vegetation typically adapted for life in saturated soil conditions, commonly known as hydrophytic vegetation.

to, clearing, digging, grubbing, stripping, removal of vegetation, dredging, grading, excavating, transporting and filling of land, construction, paving, and any other installation of impervious cover.

comprise, facilitate or result in land development.

undertaking.

undeveloped site.

not originate from a discrete point such as a sewage treatment plant or industrial discharge, but involves the transport of pollutants such as sediment, fertilizers, pesticides, heavy metals, oil, grease, bacteria, organic materials and other contaminants from land to surface water and groundwater via mechanisms such as precipitation, stormwater runoff, and leaching. Nonpoint source pollution is a by-product of land use practices such as agricultural, silvicultural, mining, construction, subsurface disposal and urban runoff sources.

Practice means any natural or planted vegetation or other nonstructural component of the stormwater management plan that provides for or enhances stormwater quantity and/or quality control or other stormwater management benefits, and includes, but is not limited to, riparian buffers, open and greenspace areas, overland flow filtration areas, natural depressions, and vegetated channels.

outside the boundaries of the site.

within the boundaries of the site.

increase in the frequency and magnitude of out-of-bank flooding (i.e.

flow events that exceed the capacity of the channel and enter the floodplain), and that are intended to protect downstream properties from flooding for the two (2) year through twenty-five (25) year frequency storm events.

limited to, a mortgagee or vendee in possession, receiver, executor, trustee, lessee or other person, firm or corporation in control of the site.

Lawrenceville Department of Planning and Zoning to the applicant which is required for undertaking any land development activity.

individual, partnership, firm, association, joint venture, public or private corporation, trust, estate, commission, board, public or private institution, utility, cooperative, city, county or other political subdivision of the State, any interstate body or any other legal entity.

reasonably be expected or anticipated to exist, after completion of the land development activity on a site as the context may require.

on a site prior to the commencement of a land development project and at the time that plans for the land development of a site are approved by the plan approving authority. Where phased development or plan approval occurs (preliminary grading, roads and utilities, etc.), the existing conditions at the time prior to the first item being approved or permitted shall establish pre-development conditions.

developed site, but excludes ordinary maintenance activities, remodeling of existing buildings, resurfacing of paved areas, and exterior changes or improvements which do not materially increase or concentrate stormwater runoff, or cause additional nonpoint source pollution.

means stormwater management facilities designed to control stormwater runoff from multiple properties, where the owners or developers of the individual properties may assist in the financing of the facility, and the requirement for on-site controls is either eliminated or reduced.

which the land development project is located.

approaches and techniques that can reduce a site’s impact on the watershed and can provide for nonstructural stormwater management.

Stormwater better site design includes conserving and protecting natural areas and greenspace, reducing impervious cover and using natural features for stormwater management.

treatment and disposal of stormwater runoff in a manner intended to prevent increased flood damage, streambank channel erosion, habitat degradation and water quality degradation, and to enhance and promote the public health, safety and general welfare.

controls or conveys stormwater runoff.

management facility or nonstructural stormwater practice.

existing runoff characteristics will be affected by a land development project and containing measures for complying with the provisions of this ordinance.

nonstructural stormwater management facilities and practices that are used to capture, convey and control the quantity and quality of the stormwater runoff from a site.

designed for a currently developed site that previously had either no stormwater management practice in place or a practice inadequate to meet the stormwater management requirements of the site.

precipitation.

management facility or device that controls stormwater runoff and changes the characteristics of that runoff including, but not limited to, the quantity and quality, the period of release or the velocity of flow of such runoff.

one or more new lots or building sites for the purpose, whether immediately or in the future, of sale, other transfer of ownership or land development, and includes divisions of land resulting from or made in connection with the layout or development of a new street or roadway or a change in an existing street or roadway.

Board of Appeals.

No owner or developer shall perform any land development activities without first meeting the requirements of this ordinance prior to commencing the proposed activity.

Unless specifically exempted by this ordinance, any owner or developer proposing a land development activity shall submit to the Director a permit application on a form provided by the Department of Planning and Zoning for that purpose.

Unless otherwise exempted by this ordinance, a permit application shall be accompanied by the following items in order to be considered:

The Stormwater Management Plan shall detail how post-development stormwater runoff will be controlled or managed and how the proposed project will meet the requirements of this ordinance, including the performance criteria set forth in Section 15.4 below.

This plan shall be in accordance with the criteria established in this section and must be submitted with the stamp and signature of a Professional Engineer (PE) licensed in the state of Georgia, who must verify that the design of all stormwater management facilities and practices meet the submittal requirements outlined in the submittal checklist(s) found in the Stormwater Design Manual.

The Stormwater Management Plan must ensure that the requirements and criteria in this ordinance are being complied with and that opportunities are being taken to minimize adverse post-development stormwater runoff impacts from the development. The plan shall consist of maps, narrative, and supporting design calculations (hydrologic and hydraulic) for the proposed Stormwater Management System. The plan shall include all of the information required in the Stormwater Management Site Plan checklist found in the Stormwater Design Manual. This includes:

documentation and supporting calculations to show that the stormwater management system adequately meets the post-development stormwater management performance criteria in Section 15.4; drawings, design calculations, elevations and hydraulic grade lines for all existing and proposed stormwater conveyance elements including stormwater drains, pipes, culverts, catch basins, channels, swales and areas of overland flow; and where applicable, a narrative describing how the stormwater management system corresponds with any watershed protection plans and/or local greenspace protection plan.

Prior to the issuance of any permit for a land development activity requiring a stormwater management facility or practice hereunder and for which the Department of Planning and Zoning requires ongoing maintenance, the applicant or owner of the site must, unless an on-site stormwater management facility or practice is dedicated to and accepted by the Director, execute an inspection and maintenance agreement, and/or a conservation easement, if applicable, that shall be binding on all subsequent owners of the site.

The inspection and maintenance agreement, if applicable, must be approved by the Director prior to plan approval, and recorded in the deed records upon final plat approval.

The inspection and maintenance agreement shall identify by name or official title the person(s) responsible for carrying out the inspection and maintenance. Responsibility for the operation and maintenance of the stormwater management facility or practice, unless assumed by a governmental agency, shall remain with the property owner and shall pass to any successor owner. If portions of the land are sold or otherwise transferred, legally binding arrangements shall be made to pass the inspection and maintenance responsibility to the appropriate successors in title. These arrangements shall designate for each portion of the site, the person to be permanently responsible for its inspection and maintenance.

As part of the inspection and maintenance agreement, a schedule shall be developed for when and how often routine inspection and maintenance will occur to ensure proper function of the stormwater management facility or practice. The agreement shall also include plans for annual inspections to ensure proper performance of the facility between scheduled maintenance and shall also include remedies for the default thereof.

In addition to enforcing the terms of the inspection and maintenance agreement, the Director may also enforce all of the provisions for ongoing inspection and maintenance in Section 15.6 of this ordinance.

The Director, in lieu of an inspection and maintenance agreement, may accept dedication of any existing or future stormwater management facility for maintenance, provided such facility meets all the requirements of this ordinance and includes adequate and perpetual access and sufficient area, by easement or otherwise, for inspection and regular maintenance.

The fee for review of any stormwater management application shall be based on the fee structure established by the Director and shall be made prior to the issuance of any building permit for the development.

The stormwater management plan for each land development project shall provide for stormwater management measures located on the site of the project, unless provisions are made to manage stormwater by an off-site or regional facility. The off-site or regional facility must be located on property legally dedicated for the purpose, must be designed and adequately sized to provide a level of stormwater quantity and quality control that is equal to or greater than that which would be afforded by on-site practices and there must be a legally-obligated entity responsible for long-term operation and maintenance of the off-site or regional stormwater facility. In addition, on-site measures shall be implemented, where necessary, to protect upstream and downstream properties and drainage channels from the site to the off-site facility.

A stormwater management plan must be submitted to the Director which shows the adequacy of the off-site or regional facility.

To be eligible for a modification, the applicant must demonstrate to the satisfaction of the Director that the use of an off-site or regional facility will not result in the following impacts to upstream or downstream areas:

The following performance criteria shall be applicable to all stormwater management plans, unless otherwise provided for in this ordinance:

All stormwater runoff generated from a site shall be adequately treated before discharge. It will be presumed that a stormwater management system complies with this requirement if:

Protection of stream channels from bank and bed erosion and degradation shall be provided by using all of the following three approaches:

year, twenty-four (24) hour return frequency storm event;

Downstream overbank flood and property protection shall be provided by controlling (attenuating) the post-development peak discharge rate to the pre-development rate for the twenty-five (25) year, twenty-four (24) hour return frequency storm event.

Extreme flood and public safety protection shall be provided by controlling and safely conveying the one hundred (100) year, twenty-four

All structural stormwater management facilities shall be selected and designed using the appropriate criteria from the Georgia Stormwater Management Manual and/or the City of Lawrenceville Stormwater Design Manual. All structural stormwater controls must be designed appropriately to meet their intended function. For other structural stormwater controls not included in the Georgia Stormwater Management Manual and/or the City of Lawrenceville Stormwater Design Manual, or for which pollutant removal rates have not been provided, the effectiveness and pollutant removal of the structural control must be documented through prior studies, literature reviews, or other means and receive approval from Director before being included in the design of a stormwater management system. In addition, if hydrologic or topographic conditions, or land use activities warrant greater control than that provided by the minimum control requirements, the Director may impose additional requirements deemed necessary to protect upstream and downstream properties and aquatic resources from damage due to increased volume, frequency, and rate of stormwater runoff or increased nonpoint source pollution loads created on the site in question.

Applicants shall consult the Georgia Stormwater Management Manual and/or the City of Lawrenceville Stormwater Design Manual for guidance on the factors that determine site design feasibility when selecting and locating a structural stormwater control.

The use of one or more site design measures by the applicant may allow for a reduction in the water quality treatment volume required under Section 15.4.1. The applicant may, if approved by the Director, take credit for the use of stormwater better site design practices and reduce the water quality volume requirement. For each potential credit, there is a minimum set of criteria and requirements which identify the conditions or circumstances under which the credit may be applied. The site design practices that qualify for this credit and the criteria and procedures for applying and calculating the credits are included in the Georgia Stormwater Management Manual and/or the City of Lawrenceville Stormwater Design Manual.

Stormwater conveyance facilities, which may include but are not limited to culverts, stormwater drainage pipes, catch basins, drop inlets, junction boxes, headwalls, gutter, swales, channels, ditches, and energy dissipaters shall be provided when necessary for the protection of public right-of-way and private properties adjoining project sites and/or public right-of-ways.

Stormwater conveyance facilities that are designed to carry runoff from more that one (1) parcel, existing or proposed, shall meet the following requirements:

Any land disturbing activity that involves a site which proposes a dam shall comply with the Georgia Safe Dams Act and Rules for Dam Safety as applicable.

System

Periodic inspections of the stormwater management system construction shall be conducted by the staff of the Department of Planning and Zoning or conducted and certified by a professional engineer who has been approved by the Department of Planning and Zoning. Construction inspections shall utilize the approved stormwater Management Plan for establishing compliance.

All inspections shall be documented with written reports that contain the following information:

If any violations are found, the applicant shall be notified in writing of the nature of the violation and the required corrective actions.

Upon completion of a project, and before a certificate of occupancy shall be granted, the applicant is responsible for certifying that the completed project is in accordance with the approved Stormwater Management Plan.

All applicants are required to submit actual “as built” plans for any stormwater management facilities or practices after final construction is completed. The plan must show the final design specifications for all stormwater management facilities and practices and must be certified by a Professional Engineer. A final inspection by the Director is required before the release of any performance securities can occur.

Stormwater management facilities and practices included in a stormwater management plan which are subject to an inspection and maintenance agreement must undergo ongoing inspections to document maintenance and repair needs and ensure compliance with the requirements of the agreement, the plan and this ordinance.

A stormwater management facility or practice shall be inspected on a periodic basis by the responsible person in accordance with the approved inspection and maintenance agreement. In the event that the stormwater management facility has not been maintained and/or becomes a danger to public safety or public health, the Director shall notify the person responsible for carrying out the maintenance plan by registered or certified mail to the person specified in the inspection and maintenance agreement.

The notice shall specify the measures needed to comply with the agreement and the plan and shall specify the time within which such measures shall be completed. If the responsible person fails or refuses to meet the requirements of the inspection and maintenance agreement, the Director may correct the violation as provided in Subsection 15.6.4 hereof.

Inspection programs by the Director may be established on any reasonable basis, including but not limited to: routine inspections; random inspections; inspections based upon complaints or other notice of possible violations; and joint inspections with other agencies inspecting under environmental or safety laws. Inspections may include, but are not limited to: reviewing maintenance and repair records; sampling discharges, surface water, groundwater, and material or water in stormwater management facilities; and evaluating the condition of stormwater management facilities and practices.

The terms of the inspection and maintenance agreement shall provide for the Director to enter the property at reasonable times and in a reasonable manner for the purpose of inspection. This includes the right to enter a property when it has a reasonable basis to believe that a violation of this ordinance is occurring or has occurred and to enter when necessary for abatement of a public nuisance or correction of a violation of this ordinance.

Parties responsible for the operation and maintenance of a stormwater management facility shall provide records of all maintenance and repairs to the Director.

If a responsible person fails or refuses to meet the requirements of the inspection and maintenance agreement, the Director, after thirty (30) days written notice (except, that in the event the violation constitutes an immediate danger to public health or public safety, 24 hours notice shall be sufficient), 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 Director may assess the owner(s) of the facility for the cost of repair work which shall be a lien on the property, and may be placed on the ad valorem tax bill for such property and collected in the ordinary manner for such taxes.

Any action or inaction which violates the provisions of this ordinance or the requirements of an approved stormwater management plan or permit, may be subject to the enforcement actions outlined in this Section. Any such action or inaction which is continuous with respect to time is deemed to be a public nuisance and may be abated by injunctive or other equitable relief. The imposition of any of the penalties described below shall not prevent such equitable relief. The imposition of any of the penalties described below shall not prevent such equitable relief.

If the Director determines that an applicant or other responsible person has failed to comply with the terms and conditions of a permit, an approved stormwater management plan or the provisions of this ordinance, he or she shall issue a written notice of violation to such applicant or other responsible person. Where a person is engaged in activity covered by this ordinance without having first secured a permit therefor, the notice of violation shall be served on the owner or the responsible person in charge of the activity being conducted on the site.

In the event the remedial measures described in the notice of violation have not been completed by the date set forth for such completion in the notice of violation, any one or more of the following actions or penalties may be taken or assessed against the person to whom the notice of violation was directed. Before taking any of the following actions or imposing any of the following penalties, the Director shall first notify the applicant or other responsible person in writing of its intended action, and shall provide a reasonable opportunity of not less than ten (10) days (except, that in the event the violation constitutes an immediate danger to public health or public safety, twenty-four (24) hours notice shall be sufficient) to cure such violation. In the event the applicant or other responsible person fails to cure such violation after such notice and cure period, the Director may take any one (1) or more of the following actions or impose any one (1) or more of the following penalties.

The stop work order shall remain in effect until the applicant or other responsible person has taken the remedial measures set forth in the notice of violation or has otherwise cured the violation or violations described therein, provided the stop work order may be withdrawn or modified to enable the applicant or other responsible person to take the necessary remedial measures to cure such violation or violations.

Upon receipt of an owner or operator’s Notice of Appeal (pursuant to Section 7.1 above) of any adverse decision made by the Director, the Director may then reverse his decision or affirm the decision by forwarding the written notice of appeal to the Zoning Board of Appeals.

A notice of appeal shall state the specific reasons why the decision is alleged to be in error, and the Director shall prepare and send to the Zoning Board of Appeals and the appellant a written response to such notice of appeal within thirty (30) working days of his receipt of the notice of appeal.

All appeals shall be heard by the Zoning Board of Appeals under their normal course of business procedures. The hearing shall be within forty-five (45) business days after receipt of the Director’s written response to such notice of appeal. The Department of Planning and Zoning shall certify the Zoning Board of Appeals’ decision within thirty (30) days after the applicable decision.

The concurring vote of three (3) members of the Zoning Board of Appeals shall be necessary to reverse any order, requirement, decision or determination of the Director.

Any party who is dissatisfied with the decision of the Zoning Board of Appeals may appeal to any court of competent jurisdiction within thirty