Alter or alteration means work done on a stormwater management system other than that necessary to maintain the system's original design and function.

Detention means the collection and storage of surface water for subsequent gradual discharge.

Existing means for purposes of the stormwater management provisions of this code, the average condition immediately before development or redevelopment commences.

Impervious surface means a surface that has been compacted or covered with a layer of material so that it is highly resistant to infiltration by water. It includes, but is not limited to, semi-impervious surfaces such as compacted clay, as well as most conventionally surfaced streets, roofs, sidewalks, parking lots and other similar structures.

Maintenance means that action taken to restore or preserve the original design and function of any stormwater management system.

Natural systems means systems which predominantly consist of or are used by those communities of plants, animals, bacteria and other flora and fauna which occur indigenously on the land, in the soil or in the water.

Rate means volume per unit of time.

Retention means the collection and storage of runoff without subsequent discharge to surface waters.

Runoff coefficient means the ratio of the amount of rain which runs off a surface to that which falls on it; a factor from which run-off can be calculated.

Sediment means the mineral or organic particulate material that is in suspension or has settled in surface or ground waters.

Site generally, any tract, lot or parcel of land or combination of tracts, lots, or parcels of land that are in one (1) ownership, or in diverse ownership but contiguous, and which are to be developed as a single unit, subdivision, or project.

Stormwater means the flow of water which results from, and that occurs immediately following, a rainfall.

Stormwater runoff means that portion of the stormwater that flows from the land surface of a site either naturally, in manmade ditches, or in a closed conduit system.

Stormwater management system means the system, or combination of systems, designed to treat stormwater, or collect, convey, channel, hold, inhibit, or divert the movement of stormwater on, through and from a site.

Surface water means water above the surface of the ground whether or not flowing through definite channels, including the following:

(1)

Any natural or artificial pond, lake, reservoir, or other area which ordinarily or intermittently contains water and which has a discernible shoreline; or

(2)

Any natural or artificial stream, river, creek, channel, ditch, canal, conduit, culvert, drain, waterway, gully, ravine, street, roadway, swale or wash in which water flows in a definite direction, either continuously or intermittently, and which has a definite channel, bed or banks; or

(3)

Any wetland.

Wetland means land that is inundated or saturated by surface water or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do or would support, a prevalence of vegetation typically adapted for life in saturated soil conditions. The term includes, but is not limited to, swamp hammocks, hardwood swamps, riverine cypress, cypress ponds, bayheads and bogs, wet prairies, freshwater marshes, tidal flats, saltmarshes, mangrove swamps, and marine meadows.

In addition to meeting the requirements of this code, the design and performance of all stormwater management systems shall comply with applicable state regulations (Chapter 17-25, Florida Administrative Code) or rules of the South Florida Water Management District and the city's subdivision standards article XIV. In all cases the strictest of the applicable standards shall apply. (See City of Pahokee subdivision standards chapter 14, article XIV.)

Editor's note— The Florida Department of Environmental Regulation regulates stormwater management systems in Chapter 17-25, Florida Administrative code. These rules provide for the delegation of authority to permit stormwater management to water management districts or local governments. Except for the Northwest Florida Water Management District, each of the water management districts has accepted this delegation, see § 17-25.090 F.A.C., and adopted stormwater management rules, see South Florida: Chapter 40E-4; Southwest Florida: Chapter 17-25 F.A.C., adopted by reference; St. Johns: Chapter 40C-42; and Suwannee: Chapter 40B-4.
 The Growth Management Act of 1985 requires local governments to adopt stormwater management regulations. Rule 9J-24 F.A.C., which establish the procedures and criteria for review of local government land development regulations, requires the inclusion of "specific programs, activities, standards, actions or prohibitions which regulate or govern the ... provision of adequate drainage facilities to control the individual and cumulative impacts of flooding and non-point source pollution in drainage basins existing wholly or in part within the jurisdiction."
 Thus, the land development regulations adopted pursuant to F.S. § 163.3202 and Rule 9J-24.033 F.A.C. must address both the water quantity and quality aspects of stormwater management. If the stormwater management LOS standards adopted by a local government in its comprehensive plan are met by the permitting requirements already established by the DER and the water management district, that locality may comply with 9J-24 by simply adopting language in the land development code requiring all nonexempt development receive appropriate permits from the DER and water management district before a development order is issued by the local government.
 If, however, the city sets stormwater management LOS standards in the comprehensive plan that will not be met through implementation of the DER and water management district permitting requirements, it is necessary to adopt additional standards and permitting provisions in the land development code.
 The following provisions are provided as suggested language for those localities that must adopt additional permitting requirements.

The following development activities are exempt from these stormwater management requirements, except that steps to control erosion and sedimentation must be taken for all development.

(1)

The construction of a single family or duplex residential dwelling unit and accessory structures on a single parcel of land.

(2)

Any development within a subdivision if each of the following conditions have been met:

a.

Stormwater management provisions for the subdivision were previously approved and remain valid as part of a final plat or development plan; and

b.

The development is conducted in accordance with the stormwater management provisions submitted with the final plat or development plan.

(3)

Bona fide agricultural activity, including forestry, provided farming activities are conducted in accordance with the requirements set forth in an approved soil conservation service conservation plan and forestry activities are conducted in accordance with the Silviculture Best Management Practices (BMP) Manual (1979) published by the Florida Division of Forestry. If the conservation plan and forestry BMP's are not implemented accordingly, this exemption shall become void and a stormwater permit shall be required.

(4)

Maintenance activity that does not change or affect the quality, rate, volume or location of stormwater flows on the site or of stormwater runoff.

(5)

Action taken under emergency conditions to prevent imminent harm or danger to persons, or to protect property from imminent fire, violent storms, hurricanes or other hazards. A report of the emergency action shall be made to the department as soon as practicable.

(a)

Performance standards. All development must be designed, constructed and maintained to meet the following performance standards:

(1)

While development activity is underway and after it is completed, the characteristics of stormwater runoff shall approximate the rate, volume, quality, and timing of stormwater runoff that occurred under the site's natural unimproved or existing state, except that the first one (1) inch of stormwater runoff shall be treated in an off line retention system or according to other best management practices as described in the stormwater management manual adopted pursuant to this code. (Refer to City of Pahokee's subdivision standards, article XIV.)

(2)

The proposed development and development activity shall not violate the water quality standards as set forth in Chapter 17-3, Florida Administrative Code.

(b)

Design standards. To comply with the foregoing performance standards the proposed stormwater management system shall conform to the following design standards:

(1)

Detention and retention systems shall be designed to comply with the stormwater management manual adopted by the city pursuant to this code.

(2)

To the maximum extent practicable, natural systems shall be used to accommodate stormwater.

(3)

The proposed stormwater management system shall be designed to accommodate the stormwater that originates within the development and stormwater that flows onto or across the development from adjacent lands.

Editor's note— [The total watershed area affecting the site may be obtained from the city engineer or United States Geological Survey maps.]

(4)

The proposed stormwater management system shall be designed to function properly for a minimum twenty (20) year life.

(5)

The design and construction of the proposed stormwater management system shall be certified as meeting the requirements of this code by a professional engineer registered in the state of Florida.

(6)

No surface water may be channelled or directed into a sanitary sewer.

(7)

The proposed stormwater management system shall be compatible with the stormwater management facilities on surrounding properties or streets, taking into account the possibility that substandard systems may be improved in the future.

(8)

The banks of detention and retention areas should be sloped to accommodate, and should be planted with, appropriate vegetation.

Editor's note— A generally accepted slope for this purpose does not exceed a four-to-one (4:1) ratio. Final slope design should consider soil types, maintenance access, side slope stabilization, basin depth, and design high water. Department of Environmental Regulation Stormwater Rules, Rule 17-25 F.A.C., require that, for safety reasons, a wet detention facility with a slope of four-to-one (4:1) ratio or greater must be fenced. In order t avoid the unsightly fencing of wet detention facilities, slopes of less than four-to-one (4:1) ratio should be encouraged.

(9)

Dredging, clearing of vegetation, deepening, widening, straightening, stabilizing or otherwise altering natural surface waters shall be minimized.

(10)

Natural surface waters shall not be used as sediment traps during or after development.

(11)

For aesthetic reasons and to increase shoreline habitat, the shorelines of detention and retention areas shall be sinuous rather than straight.

(12)

Water reuse and conservation shall, to the maximum extent practicable, be achieved by incorporating the stormwater management system into irrigation systems serving the development.

(13)

Vegetated buffers of sufficient width to prevent erosion shall be retained or created along the shores, banks or edges of all natural or man-made surface waters.

(14)

In phased developments the stormwater management system for each integrated stage of completion shall be capable of functioning independently as required by this code.

(15)

All detention and retention basins, except natural water bodies used for this purpose, shall be accessible for maintenance from streets or public rights-of-way.

(a)

Responsibility for completing and updating. The department shall compile a stormwater management manual for the guidance of persons seeking approval of a stormwater management system under this code. The manual shall be updated periodically to reflect the most current and effective practices and shall be readily available to the public. See city subdivision design and standards article XIV, section 2.5

(b)

Contents. The manual shall include:

(1)

Guidance and specifications for the design of stormwater management systems consistent with article XIV city subdivision standards and design. Acceptable techniques for obtaining, calculating and presenting the information required by this code shall be described.

(2)

Guidance in the selection of environmentally sound practices for the management of stormwater and the control of erosion and sediment. Specific techniques and practices shall be described in detail with particular attention given to the development and use of techniques that emphasize the use of natural systems.

(3)

Minimum construction specifications for stormwater management facilities in accordance with good engineering practices. (Refer to City of Pahokee subdivision standards, article XIV.)

(c)

Approval by city commission. The department shall submit the manual and subsequent revisions of it to the city commission for review and approval.

Editor's note— Numerous effective techniques have been developed for managing stormwater runoff in an environmentally acceptable manner. Local developers may be unfamiliar with some of them. The city, therefore, will compile a manual to guide the selection of appropriate techniques. The use of innovative and effective techniques should be encouraged.
 A list of helpful reference materials including existing manuals of stormwater management practices are compiled and included in the technical assistance manual that accompanies this code. An excellent source is The Florida Development Manual: A Guide To Sound Land And Water Management published by the Florida Department of Environmental Regulation.

(a)

Generally. Payment of cash in lieu of providing on-site treatment of stormwater may be accepted by the city pursuant if the two (2) conditions below are met.

(b)

Conditions.

(1)

The development site is within the area covered by a functioning regional stormwater management facility permitted by the Department of Environment Regulation or South Florida East Beach Water Management District.

(2)

The director, with the written concurrence of the city engineer, determines that the regional stormwater management facility is if sufficient size and capacity to accept the projected additional stormwater runoff without impairing its capacity to perform its current and projected functions for other areas.

(c)

Determination and payment of cash in lieu. The amount of the cash in lieu payment shall be set, and the payment shall be made, according to the following provisions.

(1)

The developer shall supply calculations, certified by a registered professional engineer, of anticipated additional post-development stormwater runoff.

(2)

A drainage payment of $1.00* per cubic foot/second (c.F.S.) of said additional stormwater runoff shall be paid by the developer to the city upon final approval of the development plan.

(3)

The amount of the payment shall be held in trust by the city and shall be used only for land acquisition and/or improvements for stormwater management purposes, and shall be applied only within the same drainage basin as the site for which it was collected.

Editor's note— [The use of a cash in lieu system requires the approval by the Florida Department of Environmental Regulation of a regional permit for an established stormwater system to accommodate the stormwater runoff that would otherwise be required to be retained on-site.]

* The dollar amount to be recommended by city engineer and approved by city commission.

(a)

Dedication. If a stormwater management system approved under this code will function as an integral part of the city-maintained regional system, as determined by the city engineer, the facilities should be dedicated to the city.

(b)

Maintenance by an acceptable entity.

(1)

All stormwater management systems that are not dedicated to the city shall be operated and maintained by one (1) of the following entities:

a.

A local governmental unit including a county, municipality, or municipal service taxing unit, special district or other governmental unit.

b.

An active water control district created pursuant to F.S. ch. 298 or drainage district created by special act, or community development district created pursuant to F.S. ch. 190, or special assessment district created pursuant to F.S. ch. 170.

c.

A state or federal agency.

d.

An officially franchised, licensed or approved communication, water, sewer, electrical or other public utility.

e.

The property owner or developer if:

1.

Written proof is submitted in the appropriate form by either letter or resolution, that a governmental entity or such other acceptable entity as set forth in paragraphs a—d. above, will accept the operation and maintenance of the stormwater management and discharge facility at a time certain in the future.

2.

A bond or other assurance of continued financial capacity to operate and maintain the system is submitted.

f.

For-profit or non-profit corporations including homeowners associations, property owners associations, condominium owners associations or master associations if:

1.

The owner or developer submits documents constituting legal capacity and a binding legal obligation between the entity and the city affirmatively taking responsibility for the operation and maintenance of the stormwater management facility.

2.

The association has sufficient powers reflected in its organizational or operational documents to:

(i)

Operate and maintain the stormwater management system as permitted by the city.

(ii)

Establish rules and regulations.

(iii)

Assess members.

(iv)

Contract for services.

(v)

Exist perpetually, with the articles of incorporation providing that if the association is dissolved, the stormwater management system will be maintained by an acceptable entity as described above.

(2)

If a project is to be constructed in phases, and subsequent phases will use the same stormwater management facilities as the initial phase or phases, the operation/maintenance entity shall have the ability to accept responsibility for the operation and maintenance of the stormwater management systems of future phases of the project.

(3)

In phased developments that have an integrated stormwater management system, but employ independent operation/maintenance entities for different phases, the operation/maintenance entities, either separately or collectively, shall have the responsibility and authority to operate and maintain the stormwater management system for the entire project. That authority shall include cross easements for stormwater management and the authority and ability of each entity to enter and maintain all facilities, should any entity fail to maintain a portion of the stormwater management system within the project.

(4)

The applicant shall be an acceptable entity and shall be responsible for the operation and maintenance of the stormwater management system from the time construction begins until the stormwater management system is dedicated to and accepted by another acceptable entity.

Editor's note— A dedication to the city may or may not be desirable depending upon the particular circumstances. The foregoing provisions permit the decision to go either way while ensuring that the stormwater management system will be operated and maintained by a responsible entity. Much of the foregoing language is based on § 17-25.027 of DER's stormwater rule.