§ 54-347. Requirements for excavations.

The following requirements apply to all Excavating activities for which a Permit is required pursuant to the provisions of this article:

(1)

Borrow pits, artificial lakes and other excavations below the normal groundwater level designed to be left open upon completion shall be sufficiently graded to avoid flooding or erosion on any off-site property or public roads, and shall not be excavated within the following minimum setback areas (measured at top of bank of Excavation):

(a)

Within 50 feet of Neighboring Property lines for excavations less than 10,000 cubic yards. The setback requirements may be reduced with the approval of the Administrator, where it is determined that sufficient buffering is otherwise provided between incompatible uses, and if the affected Neighboring Property owner(s) signs an affidavit of no objection;

(b)

Within 100 feet of Neighboring Property lines for excavations in excess of 10,000 cubic yards but less than 100,000 cubic yards in volume. The setback requirement may be reduced with the approval of the Administrator, where it is determined that sufficient buffering is otherwise provided between incompatible uses, and if the affected Neighboring Property owner(s) signs an affidavit of no objection.

(c)

Within 200 feet of Neighboring Property lines for excavations in excess of 100,000 cubic yards of volume. The Board may reduce the setback requirement where it is determined that sufficient buffering is otherwise provided between incompatible uses.

(d)

Within 200 feet of a Wetland where dewatering of an excavation in excess of 10,000 cubic yards will occur for a period greater than 30 days, unless otherwise authorized by the Administrator or the Board. An Applicant requesting a setback reduction is required to provide a groundwater drawdown analysis based on a methodology that is verifiable, reproducible and provides for monitoring to assess any hydroperiod impacts to the Wetland due to dewatering activities.

(2)

Structural and vegetative buffers may be required as necessary to prevent adverse visual, noise, vibration, dust, and safety impacts between potentially incompatible land uses.

(a)

Existing vegetation (excluding nuisance or exotic plant species) must remain in required setback areas, to the extent possible.

(b)

If existing vegetation is not sufficient to provide an adequate visual buffer, supplemental planting, berms, or berms with supplemental planting may be required.

(3)

All Excavated areas shall have side slopes no steeper than one-foot vertical drop for each four feet of horizontal distance to a minimum depth of two feet below normal water level (NWL). Below this depth, the side slopes shall be no steeper than one-foot vertical drop for each two feet of horizontal distance. In certain constrained residential situations, at the discretion of the County, pond or lake side slopes may be permitted steeper than described above if retaining walls are provided and, where required; a building permit is obtained for the wall. All Excavated ditches and swales along roadways shall have side slopes no steeper than one-foot vertical drop for each four feet of horizontal distance. The back slopes of these ditches and swales shall be no steeper than one-foot vertical drop for each three feet of horizontal distance. These standards are intended to be minimal sloping requirements, providing for maximum permissible steepness of the side slopes. The Applicant may opt to create more gradual side slopes for safety purposes.

(4)

The depth of an excavation shall not exceed 20 feet and shall not penetrate any rock strata or other aquiclude. However, at a public hearing, the Board may grant permission for Excavation in excess of 20 feet in depth if the Applicant demonstrates that the development and operation of the Excavation will not adversely affect existing or created groundwater levels, water quality, or the property of others. In this case, the Permit must contain a provision authorizing a specific depth to which excavation may occur below 20 feet.

(5)

All ongoing excavations shall be maintained by securing the property (e.g. fencing).

(6)

Upon completion of the excavation or prior to expiration of the Permit, the Excavation shall be left in a free-form configuration. Square or rectangular designs are not permissible. The banks shall be grassed to prevent erosion. Spoil piles or Stockpiling of material shall be removed from or spread upon the site pursuant to Permit stipulations. All site cleanup and stabilization activities shall be completed prior to the expiration of the Permit.

(7)

Fifteen percent of the surface area of all new commercial borrow pit lakes not part of a Master Plan approved prior to April 4, 1990, and that will not qualify as exempt utilities after closure in accordance with subsection 54-349(b)(1), shall contain Littoral Zones. The area of Littoral Zone required shall be based on the surface area of each borrow pit lake, including the area of Littoral Zone, measured at normal water level elevation. Littoral Zone designs will be considered on a case-by-case basis, but shall be vegetated, maintained and monitored in accordance with the provisions of Sections A.2 through A.13 of the Environmental Technical Manual contained in the County's Land Development Regulations. They may be created along all or a portion of the shoreline, concentrated in one or more sections of each borrow pit lake, included in islands or peninsulas, or any combination of the above. Littoral Zones may also be concentrated near the outfall of individual borrow pits or at the outfall of the most downstream pit in cases where borrow pits are hydrologically connected. The area of Littoral Zone required shall be based on the total surface area of all interconnected pits.

The Administrator shall have the authority on a case-by-case basis to modify the Littoral Zone planting and percentage requirements for an Excavation for which there will be a proven and consistent wide fluctuation in water levels in the borrow pit lake (greater than three feet fluctuation measured from normal water level), or if the areas surrounding the lake contain significant Protected Native Habitat that will be impacted if the entire Littoral Zone is created as required. In these cases, the Administrator may approve an equivalent or greater area of upland habitat conservation, wetland enhancement and/or restoration to satisfy the remaining littoral zone percentage requirement, provided that documentation is submitted assuring these areas will be preserved or conserved and managed in perpetuity in accordance with an approved Resource Management Plan. In any event, no less than five percent Littoral Zone shall be provided.

(8)

Fifteen percent of the surface area of all other lakes shall contain Littoral Zones, except those created for stormwater management purposes. In cases where existing borrow pits are connected to or otherwise made part of a stormwater management system, Littoral Zones may be installed downstream of the existing pit(s) between the pit's outfall and the point of off-site discharge. Stormwater detention lakes shall be regulated in accordance with the Environmental Technical Manual of the County's Land Development Regulations. Littoral Zones in lakes greater than one acre shall be vegetated, maintained, and monitored as described in this section. Littoral Zones in lakes less than one acre need not be vegetated; however, vegetation that establishes naturally shall be maintained in the required Littoral Zones.

(9)

During and upon completion of excavation and prior to expiration of the Permit, sediment shall be stabilized and erosion controlled. Sediment shall not be allowed to encroach into Wetlands, watercourses, or adjacent properties.

(10)

Receiving waters shall not exceed a turbidity level of 29 nephelometric turbidity units (NTU's) above natural background.

(11)

If evidence of the existence of historic resources is discovered during earthmoving activities (e.g., shell middens, aboriginal or historic pottery), all work shall cease in the area of effect and the Permittee or designee shall contact Sarasota County History Center within two working days in accordance with Chapter 66, Article III, of the Sarasota County Code. If any human skeletal remains or associated burial artifacts are discovered, all work in the area shall cease and the Permittee or designee shall contact the nearest law enforcement office and Sarasota County History Center.

(12)

There shall be no unconfined emissions of particulate matter arising from Earthmoving activities, beyond the boundary lines of the property for which an Earthmoving Permit has been issued, including any designated haul route, in accordance with F.A.C. § 62-296.

(Ord. No. 2007-024, §§ 1, 2, 9-25-2007)