§ 22-112. Construction requirements for excavations.

All requirements of the South Florida Water Management District, Permit Information Volume IV, along with the following requirements, shall apply to all excavations.

(1)

Setbacks. Excavations shall be located so that the control elevation contour of the excavation shall adhere to the following minimum setback requirements: Exception, where an excavation crosses common parcel or property lines, the setback requirements are exempt at the contiguous property lines.

a.

Fifty feet from the right-of-way line or easement line of any existing or proposed, private or public, street, road, highway or access easement. Exceptions to the above-referenced setbacks may be developed and shall be subject to final approval by the development services administrator or his designee. Said exceptions shall be based upon recognized standards for traffic engineering and road design (AASHTO and/or Manual of Uniform Minimum Standards for Design, Construction and Maintenance for Streets and Highways, State of Florida) and shall incorporate such factors as road alignment, travel speed, bank slope, road cross section, and need for barriers. However, lakes immediately adjacent to "T intersections" shall be located based on a specific design analysis by the applicant's engineer which provides for safety and traffic considerations at the intersection.

b.

Fifty feet from side, rear, or abutting property lines, except where the excavation is located in agriculturally or industrially zoned districts abutting a residentially zoned district, the setback shall be 100 feet from the residentially zoned property. Exceptions to these setbacks may be granted if the following criteria are met: installation of proper fencing (minimum six feet chain link), berms, walls, or other engineered protective measures for the portion of the property line within 100 feet of the lake. The minimum setback from any property line to the control elevation contour shall be 20 feet.

c.

From jurisdictional wetlands setbacks will be determined using standards set by SFWMD or the Department of Environmental Protection, as applicable.

(2)

Side slopes. The finished side slopes of the excavated area, expressed as the ratio of the horizontal distance in feet to one foot of vertical drop, shall be as follows:

A maximum four to one slope shall be graded from the existing grade to a breakpoint at least ten feet below the control elevation. Below this breakpoint, slopes shall be no steeper than two to one.

a.

All governing side slopes shall be considered from 20 feet outside the control elevation contour of the resulting excavation.

b.

If rock, homogenous to the bottom of the excavation, is encountered at any elevation above the breakpoint, then the remaining slope below the breakpoint shall be no steeper than 0.5 to one. If said homogenous rock is encountered below the breakpoint, then the slope below the breakpoint shall be no steeper than two to one to the rock elevation, and no steeper than 0.5 to one from the rock elevation to ten feet below the control elevation.

c.

In the event that property where a commercial or exempt agricultural excavation was previously excavated is rezoned/developed for uses other than agriculture, the excavation shall be modified to the standards for development excavations in accordance with the requirements of subsection 22-112(b) or other criteria as may be more stringent.

d.

Exceptions to the side slope requirements that may be justified by such alternatives as artificial slope protection or vertical bulkheads shall be approved in advance by the Engineering Review Services Department Director, where justification shall be documented in a design analysis prepared by a professional engineer registered in the State of Florida. Bulkheads may be allowed for no more than 40 percent of the shoreline length. Exception to the breakpoint depth may be granted by the Engineering Services Department based on historical water elevation data.

e.

No building construction permits will be issued for any proposed construction around the perimeter of any excavation where the minimum clearance between the excavation top-of-bank and the proposed building foundation is less than 30 feet, unless and until all side slopes adjacent to the proposed construction have been completed and approved by the county manager or designee. Exceptions to this requirement will be made in those instances where the perimeter of the excavation will be bulkheaded in accordance with the provisions of subsection 22-112(b)(4).

(3)

Depths. Unless site conditions, water quality or soil information indicates otherwise, the excavation depths as measured from the permitted control elevation shall be as follows:

a.

Maximum. Private and development excavations shall not exceed 20 feet in depth unless computations using the "fetch formula" of maximum depth = 5 feet + (0.015) x (mean fetch in feet) indicate that deeper depths are feasible. The mean fetch shall be computed as follows: (A+B)/2 where "A" is the average length parallel to the long axis of the excavation and "B" is the average width of the excavation as measured at right angles to the long axis.

Commercial excavations shall not exceed 20 feet in depth unless otherwise supported by the "fetch formula", or if it can be shown from a comparative water quality study that depths in excess of 20 feet will not, because of aquifer conditions or relative location to coastal saline waters, have a detrimental effect on the groundwater resources in the surrounding area.

b.

Minimum. In order to assure that unsightly conditions or undesirable aquatic growth will not occur in wet retention areas during the dry season of the year, the bottom elevation of these excavations shall be at least six feet below dry season water table, unless the portion of the lake in question is a littoral zone planting area.

c.

Over-excavation. In those instances where the excavator over-excavates the depth of the excavation by more than an average of ten percent, written justification shall be submitted to the county manager or designee by the project's surveyor/engineer providing an assessment of the impact of the over-excavation on the water quality of the excavation. If, upon review of the assessment statement by the county manager or designee and Environmental Advisory Council, the increased depth is found to be unacceptable, the permittee shall be required to fill the excavation to the permitted depth with materials and methods approved by the county manager or designee. If the depth is deemed acceptable by the county manager or designee and approved by the environmental advisory council, a penalty will be against the permittee for the volume of over-excavated material. The penalty shall be set by resolution for each additional cubic yard of excavated material.

(4)

Fencing. If, at any time, the county manager or designee finds that the location and conditions of an excavation are not in, or able to be brought into, compliance with all requirements of this article, the excavation shall be buffered with a minimum of a six-foot-high fence with "No Trespassing" signs as deemed appropriate by the county manager or designee to deter passage of persons.

(5)

Hours of operation. Hours of equipment and blasting operations shall be regulated by appropriate county ordinance and state laws. Unless otherwise approved by the county manager or designee, all excavation operations with the exception of dewatering pumps, which are within 1,000 feet of developed residential property, shall be limited to operating hours between 7:00 a.m. and 5:00 p.m., Monday through Saturday. Hours of operation for private and for commercial excavations located in Estates zoning districts shall be 7:00 a.m. to 5:00 p.m., Monday through Friday. Additionally, such excavation operations shall be in compliance with any and all county ordinances which establish operating controls by hours, days, noise level, or other parameters relating to public health, safety and welfare.

(6)

Restoration. Upon completion of the excavation operation, the subject property shall be restored as required by the 1986 State of Florida Resource Extraction Reclamation Act (F.S. ch. 378, pt. IV). Reclamation shall mean the reasonable rehabilitation of the total disturbed area where the resource extraction has occurred, and shall meet the reclamation performance standards established by the state. All disturbed areas, including the excavation side slopes above the control elevation contour and a 20-foot wide area around the entire perimeter of the excavation, measured from the control elevation contour, shall be sodded or fertilized and seeded with a quick-catch seed variety approved by the county manager or designee within 60 days of the final side slope shaping in order to minimize the potential for erosion.

(7)

Discontinuance of operations. If the excavating operation is inactive for a period of 90 consecutive days, except due to strikes or acts of God, all side slopes, including the working face, shall conform with this article and a report so stating, prepared and sealed by the project's surveyor/engineer shall be submitted to the county manager or designee. Recommencement shall also be reported to the county manager or designee. If the excavating operation is never started or if discontinued for a period of one year, that permit is void unless a written request is made by the permittee with sufficient justification for a time extension in which case the county manager or designee may authorize a permit extension for up to 180 days. A new permit must be approved prior to commencement.

(8)

Non-water management system lakes. Non-water management system lakes of a surface area of one acre or less, may be riprapped along their entire shoreline under the following conditions:

a.

Side slopes shall be no steeper than a ratio of two to one.

b.

Littoral shelf areas must conform to section 3.05.10 of the Land Development Code.

c.

Riprapping must extend down to the slope breakpoint required by subsection 22-112(2).

d.

The lake shall have protective barriers to prevent vehicular access where necessary.

e.

The lake shall meet all of the design requirements of this article and section 3.05.10 of the Land Development Code.

(9)

Amendments to approved excavations. Substantial changes to any approved excavation permit, (i.e. changes resulting in an increase of 20 percent or more in excavated volume resulting in less than 50,000 additional cubic yards), must be submitted to the Engineering Services Department for review and approval, with such approval granted in writing prior to commencement of any proposed change. Littoral shelf areas must conform to section 3.05.10 of the Land Development Code. Failure to comply with the permit requirements shall be cause for the county manager or designee to issue stop work orders on all excavation related activities taking place or planned for the subject property. Insubstantial changes shall not require prior written approval and shall include reductions in surface area not affecting water management design quantities of material to be removed. A written description of proposed insubstantial change (including an illustrated as-built as per the excavation permit) to any approved excavation shall be submitted in writing to the Engineering Services Department.

(10)

Special requirements for commercial excavations located in Estates zoning districts are as follows:

a.

Commercial excavations must be authorized by a conditional use permit for the parcel(s) where the excavation occurs.

b.

Conditional uses and excavation permits expire after one year, with a provision for one additional one-year extension upon payment of renewal and inspection fees.

c.

Blasting will not be permitted. If test holes show that rock is less than 12 feet from the original grade, removal methods must receive staff approval.

d.

Hours of operation for digging and/or off-site hauling will be 7:00 a.m. to 5:00 p.m., Monday through Friday.

e.

All areas disturbed as a result of fill storage must be seeded and mulched upon completion of construction. Prior to release of the performance bond, the planted seed must reach a height of six inches. Rye grass is acceptable for this purpose.

f.

Lake location and size. For parcels five acres in size and smaller, the surface of the lake can occupy a maximum of 40 percent of the lot area.

For parcels over five acres and up to ten acres, the surface area of the lake can occupy a maximum of 45 percent of the lot area.

For parcels over ten acres, the surface area of the lake can occupy a maximum of 50 percent of the lot area.

Finished lakes shall be irregularly shaped with no comers less than 40 feet in radius, and must otherwise conform to section 5.05.08 of the Land Development Code.

Setbacks less than 50 feet from control elevation contour to property line are allowed if proper fencing (72 inches high and "childproof") is used. Under no circumstances will a setback of less than 20 feet from control elevation contour to property line be allowed. There shall be no exceptions to the 50 foot front yard setback from the road right-of-way line.

g.

Depths. Commercial excavations located in Estates zoning districts shall not exceed 20 feet in depth. The minimum depth shall be 6 feet below low water at the middle of the excavation. See subsection 22-112(1) for exceptions.

h.

Sideslopes shall be no steeper than one foot vertical to four feet horizontal to a depth of ten feet below control elevation and may be as steep as one foot vertical to two feet horizontal below that elevation. Exception to the breakpoint depth may be granted by the Engineering Services Department based on historical water elevation data.

i.

Building envelope. A minimum one-acre building envelope is required. The envelope shall be contiguous, rectangular in shape, and may extend to the property lines and include setbacks. The minimum dimension of any side of the rectangle shall be 150 feet.

j.

Stockpiles. The stockpile area may occupy the future homesite. Proper erosion control and sediment measures (meeting PDES standards) must be used at the stockpile site.

k.

Littoral zone plantings must conform to section 3.05.10 of the Land Development Code.

l.

Federal and state agency permits. Any excavation in an area containing SFWMD (Southwest Florida Water Management District), DEP (Department of Environmental Protection) or USACE (United States Army Corps of Engineers) jurisdictional vegetation must obtain a permit from the applicable agency prior to issuance of the excavation permit.

(11)

Erosion control. Upon completion of any lake construction, a silt fence must be installed around all portions of the lake which are contiguous to proposed new construction. Portions of the silt fence may be removed after the new construction (i.e. residences, roads, drainage) adjacent to that section of silt fence has been approved. Alternate means of erosion control, meeting federal and state standards, may be approved by the Engineering Services Director, or designee, upon submittal of a plan showing the proposed erosion control method.

(Ord. No. 04-55, § 2.E.; Ord. No. 2006-04, § 4)