7.1.1

General. In addition to meeting the requirements of these land development regulations, the design and performance of stormwater management systems shall comply with applicable state and water management district regulations (chapter 62, rules of the Florida Department of Environmental Protection; and 40B-4 rules of the water management district, Florida Administrative Code, as amended). In all cases the strictest of the applicable standards shall apply.

7.2.1

General exemptions. The following development activities are exempt from these land development regulations, except that steps to control erosion and sedimentation must be taken for all development and any development exempt from chapter 62 or 40B-4 as cited above which is adjacent to or drains into a surface water, canal, or stream, or which empties into a sinkhole, shall first allow the runoff to enter a grassed swale or other conveyance designed to percolate 80 percent of the runoff from a three year, one hour design storm within seventy-two (72) hours after a storm event. In addition, any development except [exempt] from chapter 62 or 40B-4, as cited above which is directly discharged into an outstanding Florida water shall include an additional level of treatment equal to the runoff of the first one and one-half inches of rainfall from the design storm consistent with chapter 62, Florida Administrative Code, as amended. In order to meet the receiving water quality standards of chapter 62, F.A.C., stormwater discharge facilities shall be designed so as not to lower the receiving water quality below the minimum condition necessary to assure the suitability of water for the designated use of its classification as established in chapter 62, Florida Administrative Code, as amended.

1.

The clearing of land which is to be used solely for agriculture, silviculture, floriculture, or horticulture provided no obstruction or impoundment of surface water will take place. Also, the construction, maintenance, and operation of self-contained agricultural drainage systems provided adjacent properties will not be impacted and sound engineering practices are followed.

2.

The construction, alteration, or maintenance of a private residence or agricultural building provided the total impervious area is less than 10,000 square feet (i.e., house, barn, driveways) and provided further that the residence or agricultural building is not adjacent to an outstanding Florida water or adjacent to or drains into a surface water, canal, or stream, or which empties into a sinkhole.

3.

The connection of a system to an existing permitted system provided the existing system has been designed to accommodate the proposed system.

4.

The placement of culverts whose sole purpose is to convey sheet flow when an existing facility is being repaired or maintained provided the culvert is not placed in a stream or wetland.

5.

Existing systems that are operated and maintained properly and pose no threat to public health and safety.

6.

Connections to existing surface water management systems that are owned, operated, and maintained by a public entity provided, under ordinance, the proposed connections comply with a surface water management plan compatible with the water management district's requirements.

7.

Any development within a subdivision if each of the following conditions has 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 construction plan.

8.

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 board of county commissioners and water management district as soon as practicable.

7.3.1

Natural drainage system utilized to extent feasible. To the extent practicable, all development shall conform to the natural contours of the land and natural and preexisting man-made drainage ways shall remain undisturbed.

7.3.2

Lot boundaries. To the extent practicable, lot boundaries shall be made to coincide with natural and preexisting man-made drainage ways within subdivisions to avoid the creation of lots that can be built upon only by altering such drainage ways.

7.3.3

Developments to drain properly. All developments shall be provided with a drainage system that is adequate to prevent the undue retention of stormwater on the development site. Stormwater shall not be regarded as unduly retained if:

1.

The retention results from a technique, practice or device deliberately installed as part of a sedimentation or stormwater runoff control plan approved by the water management district; or

2.

The retention is not substantially different in location or degree than that experienced by the development site in its pre-development stage, unless such retention presents a danger to health to safety.

7.3.4

Stormwater management—General. All developments shall be constructed and maintained so that post-development runoff rates and pollutant loads do not exceed pre-development conditions. 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-half inch of stormwater runoff shall be treated in an off line retention system or according to other best management practices as described in the water management district's surface water management permitting manual, as amended. More specifically:

1.

No development may be constructed or maintained so that such development impedes the natural flow of water from higher adjacent properties across such development, thereby causing substantial damage to such higher adjacent properties, and

2.

No development may be constructed or maintained so that stormwaters from such development are collected and channeled onto lower adjacent properties.

7.3.5

Sedimentation and erosion control. Final plat approval for subdivisions may not be given with respect to any development that would cause land disturbing activity subject to the jurisdiction of the water management district, unless the water management district has certified to the county, either that:

1.

The proposed construction plans are approved for permitting by the water management district; or

2.

The water management district has examined the preliminary plat for the subdivision and it reasonably appears that permits for such subdivision improvements can be approved, upon submission of the subdivider of construction plans. However in this case, construction of the development may not begin until the water management district issues its permit.

For the purposes of this section, land disturbing activity means: (1) use of the land in residential, industrial, educational, institutional, or commercial development, or (2) street construction and maintenance that results in a change in the natural cover or topography and that may cause or contribute to sedimentation.

7.3.6

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

Facilities which directly discharge into an outstanding Florida water shall include an additional level of treatment equal to the runoff of the first one and one-half inches of rainfall from the design storm consistent with chapter 62, Florida Administrative Code, as amended, in order to meet the receiving water quality standards of chapter 62, Florida Administrative Code, as amended. Stormwater discharge facilities shall be designed so as not to lower the receiving water quality below the minimum conditions necessary to assure the suitability of water for the designated use of its classification as established in chapter 62, Florida Administrative Code, as amended.

7.3.7

Design standards. To comply with the foregoing standards the proposed stormwater management system shall conform with the following.

1.

Detention and retention systems shall be designed in conformance with the water management district's surface water management permitting manual, as amended.

2.

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

3.

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

4.

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

5.

Design and construction of the proposed stormwater management system shall be certified as meeting the requirements of these land development regulations and the water management district's surface water permitting manual, as amended, by a professional engineer, architect, or landscape architect, registered in the State of Florida.

6.

No stormwater may be channeled or directed into a sanitary sewer.

7.

The proposed stormwater management system shall coordinate with and connect to the drainage systems or drainage ways on surrounding properties or roads, whenever practicable.

8.

Use of drainage swales rather than curb and gutter and storm sewers in subdivision is provided for in article 5 of these land development regulations. Private roads and access ways within unsubdivided developments shall utilize curb and gutter and storm drains to provide adequate drainage if the grade of such roads or access ways is too steep to provide drainage in another manner or if other sufficient reasons exist to require such construction.

9.

Stormwater management systems shall be designed and constructed to provide retention of run-off volumes such that the peak discharge from the developed site shall not exceed the equivalent peak discharge from the natural or undeveloped site.

10.

The board of county commissioners may require any water retention areas to be fenced and screened by trees or shrubbery.

11.

In areas where high ground water and other conditions exist and it is deemed necessary by the board of county commissioners, subsurface drainage facilities shall be installed. If a wearing surface (see article 5 of these land development regulations) and subsurface drainage facilities are required, all subsurface drainage facilities shall be installed by the subdivider prior to the paving of the street.

12.

All required improvements shall be installed so as to maintain natural watercourses.

13.

Construction specifications for drainage swales, curbs and gutters are contained in article 5 and appendix A of these land development regulations.

14.

The banks of detention and retention areas shall be sloped to accommodate and shall be planted with vegetation which will maintain the integrity of the bank.

15.

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

16.

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

17.

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

18.

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

19.

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.

20.

In phased developments, the stormwater management system for each integrated stage of completion shall be capable of functioning independently as required by these land development regulations.

21.

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.

7.4.1

Maintenance by an acceptable entity. All stormwater management systems that are not dedicated to the county shall be operated and maintained by one of the following entities:

1.

A local governmental unit including a school board, special district or other governmental unit.

2.

A regional water management agency or an active water control district created pursuant to F.S. chapter 298, as amended, or drainage district created by special act, or special assessment district created pursuant to F.S. chapter 170, as amended.

3.

A state or federal agency.

4.

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

5.

The property owner or developer if:

a.

Written proof as submitted in the appropriate form by either letter or resolution, that a governmental entity as set forth in paragraphs 1. through 3. above, will accept the operation and maintenance of the stormwater management and discharge facility at a time certain in the future.

b.

A surety bond or other assurance of continued financial capacity to operate and maintain the system is submitted to the board of county commissioners. The developer shall maintain and repair all improvements which these stormwater management regulations require the developer to construct. The developer shall post a maintenance bond to cover at least ten percent of the estimated costs of all required stormwater improvements. (See appendix A.)

6.

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

a.

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

b.

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

1.

Operate and maintain the stormwater management system as permitted by the water management district.

2.

Establish rules and regulations.

3.

Assess members.

4.

Contract for services.

5.

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.

7.4.2

Phased projects. If a project is to be constructed in phases and subsequent phases will use the same stormwater management systems 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.

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.

7.4.3

Applicant as acceptable entity. 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.