§ 3.05.10. Littoral Shelf Planting Area (LSPA)

The purpose and intent of a littoral shelf planting area (LSPA) is to establish a planted area within an excavated lake serving as a wet detention pond as part of a stormwater management system that will support wetland plants, improves the water quality within the lake and provides habitat for a variety of aquatic species including wading birds and other waterfowl. Contained within such a lake, this area will typically function as a freshwater marsh. Accordingly, the following requirements have been established in order for the LSPA to be designed and maintained to accomplish this stated purpose and function.

A.

Design requirements.

1.

Area requirements. The total area of the LSPA shall be calculated as a percentage of the total area of the lake at control elevation. Area requirements vary within the County and are as follows:

a.

Rural Fringe Mixed Use District - 30 percent. This requirement may be reduced subject to the incentives identified in section 3.05.07 F.4.b.;

b.

All other areas - 7 percent.

2.

Location criteria. Unless otherwise allowed for, the LSPA shall be concentrated in one location of the lake(s), preferably adjacent to a preserve area, in order to maximize its habitat value and minimize maintenance efforts. Multiple locations for meeting the LSPA area requirement within a single lake shall be allowed as long as a single LSPA is no smaller than 1,000 square feet. Whenever possible, the LSPA should be located away from residential lots in order to avoid maintenance and aesthetic conflicts with residential users, and the LSPA shall be located adjacent to control structures or pipe outlets or inlets in order to maximize water quality benefits. However, the LSPA shall be located no closer than 20 feet from any discharge structure or pipe intake so as to not impede flow. If the LSPA is located around a discharge structure , the 20-foot setback shall extend waterward of the discharge structure to a point in the center of the lake. For interconnected lake systems, the total required area of the LSPA for all lakes may be configured within a single lake and at one location.

3.

Shelf elevation. The design elevation(s) of the LSPA shall be determined based on the ability of the LSPA to function as a marsh community and on the ability of selected plants to tolerate the expected range of water level fluctuations. Generally, marsh communities in this area have a hydroperiod of between 6 and 10 months. Wet seasonal water levels range from 12 to 24 inches above ground elevation. Dry seasonal water levels are six inches below ground elevation for an average year and 46 inches below ground elevation for a one in ten year drought. The design of the shelf may deviate from these reference values if site-specific data and information is presented that supports the proposed elevations.

4.

Shelf configuration. The LSPA shall be designed so that the slope of the shelf is as flat as possible. An undulating bottom allowing for shallow pooling during the dry season is encouraged. Shelves may be terraced to provide for varying elevations for different plant species. The area requirements specified in 3.05.10 A.1 shall only be satisfied by those areas planted on a shelf that has an average slope of 8:1 or flatter. Shelves having undulating bottoms and terraced configurations shall be deemed to meet the slope requirements if the average slope across the shelf is 8:1 or flatter.

5.

Plant selection and specifications. Plants shall be selected based on the expected flooding durations and maximum water depths for which the selected plants can survive. The LSPA shall be initially planted with at least 3 different species of native, nursery grown or otherwise legally obtained vegetation. No species shall constitute more than 50 percent of coverage, and at least 1 species shall be herbaceous. Spacing shall be no more than: 20 feet for trees; 5 feet for shrubs; and 36 inches on center for herbaceous plants. At the time of planting, minimum size shall be: 3 gallon (minimum 4 feet high) for trees; 1 gallon for shrubs and 12 inches for herbaceous plants. Clustering of plants shall be allowed to provide for scattered open areas as long as the open areas do not constitute more than 20 percent of the required shelf area and the elevations of the open areas are at least a foot deeper than the surrounding planted area.

6.

Posted area. The boundary of the LSPA shall be posted with appropriate signage denoting the area as a LSPA. sign (s) should note that the posted area is a Littoral Shelf Planting Area and contain specific instructions to ensure that the planted area will not be subjected to herbicidal treatments or other activities that will kill the vegetation. The signs shall be no closer than 10 feet from residential property lines; be limited to a maximum height of 4 feet and a maximum size of 2 square feet; and, otherwise comply with section 5.06.00. A minimum of two signs shall be provided to mark the extent of the LSPA. Maximum sign spacing shall be 150 feet.

7.

Required information. The planting plan for the LSPA shall provide the following information:

a.

Calculation table showing the required area (square feet) for the LSPA and its percentage of the total area at control elevation;

b.

Control elevation and dry season water table;

c.

Maximum water depth (feet) and estimated number of months of flooding for the range of planted elevations within the LSPA;

d.

A plant list to include the appropriate range of elevations for each specified plant species, spacing requirements, and plant size;

e.

Planting locations of selected plants.

B.

Operational requirements: Littoral shelf planting areas shall be maintained according to the following requirements:

1.

Eighty percent vegetative coverage of the LSPA is required within a 2-year period following the initial planting and shall be maintained in perpetuity. Native plants that recruit within the LSPA will be counted towards this coverage requirement except as required per section 3.05.10 B.2 below. The LSPA must be kept free of refuse and debris.

2.

Prohibited exotics and nuisance species shall be removed as they occur, manually or with U.S. Environmental Protection Agency approved herbicides. Prohibited exotics are those species as listed in this section 3.05.08. For the purpose of this section, nuisance species include those species listed as Class I and Class II Prohibited Aquatic Plants specified in Chapter 62C-52.011, Florida Administrative Code. Cattails shall be removed manually or with U.S. Environmental Protection Agency approved herbicides when they exceed ten percent coverage of the required LSPA area.

C.

Application to existing lakes. All previously approved projects requiring littoral plantings shall meet the operational requirements set out in LDC section 3.05.10 B. above.

1.

Projects with previously approved littoral planting requirements constructed according to standards required at the time of approval, that do not meet the operational requirements of 3.05.10 B., shall meet the current standards subject to the following criteria:

a.

The amount of planted area shall be the same as that required in the original approval;

b.

The property owner shall assess the existing slopes and elevations in order to determine the appropriate location of the plantings subject to the criteria found in section 3.05.10 A.3. The planted area shall be consolidated as much as possible subject to the criteria found in 3.05.10 A.2.

c.

Subject to the assessment described in b., the existing planting slopes should be as flat as possible but the 8:1 requirement of 3.05.10 A.4. shall not be required. Re-grading of existing slopes will not be required;

d.

Plant selection and specifications shall conform to section 3.05.10 A.5;

e.

Signage of the planted littoral areas shall be required subject to 3.05.10 A.6.; and

f.

A written assessment and site plan shall be required if it is determined by the assessment of the lakes that the new littoral shelf planting area will differ from the approved plan of record.

2.

For amendments to approved excavations where the proposed amendments will modify the previously approved lake shoreline or increase the previously approved lake area, signage of the planted littoral areas shall be required subject to LDC section 3.05.10 A.6.

a.

For amendments that modify less than 20 percent of the previously approved shoreline but increase the previously approved lake area, only the additional portion of the lake shall be used to calculate the additional LSPA area using the percentage requirements of LDC section 3.05.10 A.1. (See Figure 3.05.10 below). This additional LSPA shall conform to the design requirements of LDC section 3.05.10 A.

b.

For amendments that modify 20 percent or more of the previously approved shoreline , the total lake area shall be used to calculate the LSPA area using the percentage requirements of LDC section 3.05.10 A.1. (See Figure 3.05.10 below). The LSPA shall conform to the design requirements of LDC section 3.05.10 A.

Figure 3.05.10 - Modified Littoral Shelf Planting Area

D.

Exemptions. Lake excavations activities which are lawfully permitted and used for aquaculture shall be exempt from the LSPA requirements. Lake excavation activities subject to the Resource Extraction Reclamation Act (Ch. 378, Part IV, Fla. Stat.) shall be exempt from the LSPA requirements but shall otherwise be required to follow the mine reclamation requirements required in the Code of Laws of Collier County. Exempted lake excavations that are modified to allow the lake to function as a wet detention pond as part of a stormwater management system shall no longer be exempted from this section and shall meet the standards contained herein at the time of modification.

(Ord. No. 04-72, § 3.K; Ord. No. 06-63, § 3.O; Ord. No. 07-67, § 3.H; Ord. No. 16-27, § 3.K)