Stormwater Management Report

Transcription

1 Stormwater Management Report Autumn Woods Community Naples, FL 7/7/2014 Prepared for: Autumn Woods Master Association 6720 Autumn Woods Boulevard Naples, FL Prepared by: Autumn Woods Lakes Committee

2 Table of Contents 1. Overview 2. Autumn Woods Stormwater Management System a. How the system works b. Purpose of lake system c. Permitting agencies (Federal, State, County) 3. Lake Bank Erosion a. Lake Bank Erosion Causes Fluctuating Lake Levels and Point Discharges b. Preventing and Repairing Lake Bank Erosion (rock rip rap, geotube, geo web, geo grid, turf paver stones, littoral plantings and rough vegetation). c. Addressing/preventing point discharges i. Drainage pipe outfall repair options (headwall/french drain) ii. Gutters and Rain gardens 4. Lake Water Quality a. Types of Pollutants in Stormwater Runoff b. Causes of Algae Blooms c. Prevention of Algae Blooms d. Techniques for Improving Water Quality 5. Program of Action a. Objectives/goals b. Budgeting/repairs/recommendations c. Education Homeowner s Manual Updates Appendices: A. SFWMD Notice of Violations (3 pages). B. Sample Budgeted Improvement Program (11 pages). C. Conceptual Project Schedule (1 page). D. Figure/Illustration Credits (1 page). 2

3 1. Overview The initial purpose of this report was to develop solutions in response to the notice of violation that our community received in 2011 from the South Florida Water Management District (SFWMD Letter in Appendix A). The SFWMD is the state agency that permitted the Autumn Woods stormwater management system when the community was initially being developed back in The Autumn Woods Master Homeowners Association is responsible for operating and maintaining the community stormwater system is accordance with the issued permits. The notice of violation identified issues with the lake banks where the slopes were too steep and washout areas had been observed. Since receiving the notice violation various price proposals have been received from vendors, inspections conducted, and even some limited remedial measures have been implemented. The most recent lakes committee was established in October, In addition to addressing solutions to the SFWMD notice of violation, the committee was asked to address water quality issues with the lakes. This is an effort to provide a comprehensive program of action in reestablishing our community lakes as a resource that enhances the value and quality of our community. We have developed this report with the following objectives in mind for the community stormwater management system: i. Flood protection ii. Erosion control iii. Improved aesthetics iv. Enhanced property values v. Efficient nutrient removal vi. Effective sediment removal vii. Provide food and habitat for wildlife This report first provides an overview of the water management system. Next, we identify the sources of our erosion problems. We then look at possible solutions. Next, we look at lake water quality issues and possible remedies. What we learned is that there is an overlap between resolving our erosion problems and addressing water quality concerns. Many of the techniques and measures to eliminate our erosion problems may also help us to improve our lake system water quality. Finally, we provide a program of action that includes budget alternatives for addressing and improving our stormwater management system. 3

4 2. Autumn Woods Water Management System a. How the system works: Autumn Woods has 20 interconnected lakes/ponds that form the stormwater management system for the community. The lakes/ponds are interconnected by 24 inch diameter reinforced concrete pipes (RCP). Roadway drainage discharges to the lakes via the concrete valley gutters along the sides of the community roads that convey the water to storm inlets, which in turn are connected to the lakes by 15 inch to 24 inch diameter underground RCP storm sewer pipe. Figure 1: Aerial of Autumn Woods Community and Lakes Numbered 1 thru 20. 4

5 Figure 2: Excerpt from Autumn Woods Drainage Plans Depicting Drainage Areas (DA 1 thru DA 3); Lakes; Outline of Road/Lots and Interconnect Pipes between Lakes Table of Autumn Woods Lake System By Number, Area and Control Elevation Lake Number (1 thru 20) Lake Area (acres) Lake Control Elevation (CE)(ft, measured at CE NGVD) Total

6 Typically the front half of the residential lots/buildings drain toward the roadway drainage system. The rear half of the residential areas will drain either directly to an adjacent lake via sheet flow or to a swale which drains to an inlet structure connected to the roadway drainage system where the residence does not back up to a lake. Some of the residential buildings/homes have roof gutters that create point discharges draining towards the street, lakes, or swales. The roof gutter drainage systems are not considered part of the community maintained drainage system. The roadway drainage system, drainage inlets connected to RCP, interconnect pipes and control structures are considered part of the community maintained drainage system. Figure 3: Autumn Woods development plan excerpt depicting cross section across Lots, Road and Lake. Lot fronts drain to roads and rear of lots drain to the lakes. The Autumn Woods lake system outfalls to the Gordon River Extension via a control structure. The Gordon River Extension is the canal located between the southeast side of Autumn Woods and the west side of the Pine Ridge Industrial Park. The Gordon River Extension flows south under Pine Ridge Road and eventually ties into the Gordon River, which outfalls to the Gulf of Mexico. 6

7 Figure 4: Aerial View of generalized drainage pattern for outfall of Autumn Woods into the Gordon River extension, Naples Bay and Ultimately the Gulf of Mexico. The Autumn Woods main outfall control structure (CS 1) has a control elevation set at 9.0 ft, NGVD, which means that stormwater will not discharge until the lakes are at that prescribed elevation. There are internal control structures (CS 2A, 2B, & 2C) adjacent to the largest wetland and preserve area of Autumn Woods. These are set at a higher control elevation of 10.5 ft, NGVD. The higher control elevations are intended to maintain and mimic the wetland hydro periods within the wetlands. In addition the lined effluent pond/lake located on the north side of Red Oak Blvd has a water level control/overflow set at 12.5 ft, NGVD. 7

8 Figure 5: Plan Excerpts of Drainage Control Structures. CS 1 limits the discharge offsite and the other Control Structures CS 2A, CS 2B, CS 2C and CS 3 are water level control structures within the lake system that are intended to maintain the lake levels. 8

9 The Autumn Woods stormwater lakes are also designed to receive the stormwater runoff from the North Naples United Methodist Church campus and the Goodlette Frank Roadway right of way/ FPL Easement adjacent to the community. The total acreage of the Autumn Woods stormwater management system drainage area is acres, of which 51.7 acres is water management, 29.8 acres is pavement, 98.1 acres is building coverage, 8.6 acres is wetland preserve, and 57 acres is other pervious areas (open space, upland preserve, recreation area, and FPL easement). In the drainage map below, the area labeled DA1 has a control elevation of 9.0 ft, NGVD; the area labeled DA2 has a control elevation of 10.5 ft, NGVD and the effluent pond (labeled DA3) has an overflow elevation of 12.5 ft, NGVD. Figure 6: Excerpt of drainage master plan for community depicting offsite flow drainage areas G1 thru G3, NNUMC drainage area, and site drainage areas DA1 thru DA3. 9

10 b. Purpose of the lake system: The stormwater system provides flood control for the community as well as providing stormwater quality treatment through detention in the lakes prior to out falling to the receiving system. The lakes are man made and the fill generated from excavating the lakes was used by the developer to elevate the roads and building pads for the community residences. The lake banks were excavated at a 4 foot horizontal to 1 foot vertical slope (4:1) and at a point below the water this slope changes to a 2 foot horizontal to 1 foot vertical slope (2:1). The lake depths are a minimum of 8 feet and a maximum of 12 feet (from control elevation). Figure 7: Drainage plan excerpt depicting the lake cross sections and littoral planting details. Only a small portion of the original lake banks were planted with littorals. In looking at flood control, the lakes are designed to contain a 25 year, 3 day storm event, which equates to 11.6 inches of rain. During such an event, the drainage system (i.e. lakes, swales and wetlands) contains the stormwater, so the roads and residences do not flood. The system is also designed to discharge to the receiving system (Gordon 10

11 River Extension) at a rate of less than 0.15 cfs/acre, or a peak discharge of cfs for the entire community. In the area of the community where the lakes are at a control elevation of 9.0, the minimum road centerline elevation is 11.6 and where the lakes have a control elevation of 10.5, the minimum road centerline elevation is In addition, the system is designed for a 100 year, 3 day storm event, which equates to 14.5 inches of rain. During such an event, the drainage system, yards and even roads store the rainfall, so the residential structures are spared from flooding. In the area of the community with the lakes at a control elevation of 9.0, the minimum finished floor elevation is 12.6 and where the lakes have a control elevation of 10.5, the minimum finished floor elevation is In looking at water quality treatment, our area averages more than 50 inches of rainfall per year. Most rainfall events result in less than an inch of rain (more than 90%). This first flush of rainfall is what conveys the pollutants (i.e. oils, greases, fertilizers, heavy metals, silts) to the stormwater system for treatment. For Autumn Woods, the treatment occurs within the lakes/ponds. The polluted water has an opportunity to be detained in the lakes/ponds before being released to the receiving system. Particulates have an opportunity to settle out and the resonance time allows for treatment resulting in improved outfall water quality. Our system is considered a wet detention system. Pollutant removal efficiencies for a well maintained wet detention system are: Total Suspended Solids (TSS) = 75 to 85% Total Nitrogen (TN) = 37 to 60% Total Phosphorus (TP) = 59 to 85% Metals = 40 to 80% Other systems are considered dry where the stormwater goes into sodded areas and there is not a lake/pond (i.e. certain roadway drainage systems, or sometimes seen in shopping centers for pretreatment areas). In addition, there are retention systems where the water is completely contained within the stormwater system and is not released to a receiving body via a control structure. For retention systems, the stormwater is being conveyed by the groundwater through percolation. For our community, the stormwater system is likely operating per the permit approval with the water being released from the outfall. For those living on the lakes, though they see the negative impacts of the treatment process occurring within the lakes (algae blooms). c. Permitting agencies (Federal, State, County) The main permitting agency for approving the community stormwater system is the South Florida Water Management District (SFWMD). The developer had to secure a SFWMD permit prior to constructing the community improvements. The criteria used for securing the SFWMD permit was also used in securing the infrastructure permit 11

12 approvals from Collier County (plat and construction plans, aka PPL for the single family residential areas and site development plans (SDP) for the community center and multifamily areas). In addition to issuing the stormwater permit for the community, the SFWMD issues water use permits as well because of the relationship of water use consumption for irrigation (i.e. wells, lake pumps) and the impact that water use consumption can have on stormwater systems (i.e. lake drawdown caused by irrigation demands). 3. Lake Bank Erosion a. Causes Fluctuating Lake Levels and Point Discharges: There are two principle causes of the erosion along the lake banks. The first is caused by the fluctuating lake levels. The lake levels fluctuate by a 2 to 3 foot vertical change between the wet and dry seasons. These levels are exasperated by irrigation lake pump withdrawals and nearby public water supply wells in the northern part of the community. The lake banks within the fluctuation zone were originally sodded and over time the sod died and bare soil was exposed. The soil in time erodes due to wave action or sheet flow of stormwater runoff from the surrounding development. The erosion caused by the fluctuating water levels will occur over either the entire, or a long run of the shoreline as illustrated in the pictures below. Whenever the bank drop off exceeds 9 inches, the SFWMD staff will consider this condition to be a non compliance issue and require remediation. Figure 8 The picture to the left depicts the beginning stages of shoreline erosion where the fluctuating water levels have begun to eliminate the turf along the lake banks and exposed soil is the result (Autumn Woods Lake 15). Figure 9 The picture to the right depicts the later stages of shoreline erosion where the shape of the bank is no longer 4:1 and has a drop off at the top of the bank (Autumn Woods Lake 7). 12

13 The second cause of lake bank erosion is caused by point discharges of stormwater. Point discharges are a concentration of stormwater runoff that may cause erosion in a small area. The point discharges are typically due to roof gutters that direct water to the side yards, or gutters that may directly discharge into the lakes at either the top of bank, or somewhere along the bank slope. It also may be due to the concentration of runoff between buildings/homes. Other point sources may include pool drain lines, too. The point sources of stormwater runoff will cause isolated spots to erode, which look like little gullies. Figure 10 Picture to the left is a flex pipe for roof drainage creating a point discharge and an isolated area of erosion (Autumn Woods Lake 7). Pictured to the right is another flex pipe floating in a lake. Such a loose pipe causes erosion when it begins to flow and moves around (Autumn Woods Lake 7). 13

14 b. Preventing and Repairing Lake Bank Erosion The way to prevent erosion of the lake banks is to harden the bank either by something structural, vegetative, or a combination. One alternative is to regrade the lake bank to the proper slope and replant it with appropriate littoral plantings. Structural improvements may include and are not limited to: rock rip rap, geo tube, geo web, geo grid, and turf stone pavers. Using appropriate vegetation in combination with structural improvements, or even with a restored earthen bank slope may be sufficient where point discharges have been eliminated. The following pictures illustrate the different improvement techniques: Rock Rip Rap Pictures Figure 11: Rip rap option without vegetation (left) and with vegetation (right). Use of rip rap is limited by the SFWMD rules and is typically in locations subject to significant wave action. 14

15 Geo Tube Pictures Figure 12: Geotube option under construction (left) and completed (right) with vegetation planted on top. Geotextile is filled with sand/soil from the lake bottom and covered with soil and then planted to stabilize the shoreline. Geo web pictures Figure 13: Geoweb installed (left) with soil and sod plugs. Geoweb being installed (right) by hand with plastic connectors used to hold the pieces together. 15

16 Geo grid pictures Figure 14: The pictures are schematic sections of the geo grid system that consists of horizontal layers of the geogrid material that is then covered with soil and vegetated. The schematic to the left is a 2 dimensional section and the schematic to the right provide more of a 3 dimensional cut away view. Turf stone paver pictures Figure 15: Picture above starting with the upper left is a concrete flume replaced with turf stone pavers (upper right), which allow vegetation to grow in (lower right) and eventually blend in with the surrounding vegetation (lower left). 16

17 Littoral plantings and rough vegetation The littoral zone is the part of a lake that is close to the shore. In lake environments the littoral zone extends from the high water mark, which is rarely inundated, to shoreline areas that are permanently submerged. Littoral plants are vegetation that survive and thrive in littoral zones. Rough vegetation consists of littoral plants, or other native grasses/plants that grow in the higher reaches of the lake bank (i.e. near top of bank) that would have deeper roots and help dissipate stormwater flows absorb nutrients. The deeper root systems also help to hold the lake bank together during periods of heavy runoff, or when inundated with water. Having littoral plantings within the water and running up the bank slope allows a more natural appearance to the lakes (Figures 17 and 18). This is in contrast to a lake lacking littoral plantings that has a barren sand/soil strip exposed edge during the dry season when the water levels drop and 8 to 12 feet of additional lake bank are exposed (Figures 8 and 9). Figure 16: The sketch above shows the relationship between height at which grasses are allowed to grow and the corresponding depth of their roots. The well groomed grasses on the left have a much shallower root system than the grasses on the right that are permitted to grow more. 17

18 Figure 17: Pictured above are littoral plantings of different varieties. The rough edge, approximately 10 ft up from the water s edge allows for appropriate vegetation to take up nutrients and to also have a deeper root system to hold the bank together. 18

19 Figure 18: Pictured above is a well established littoral planting and rough area along a residential area in SW FL that serves many functions (erosion control, water quality, and aesthetics). Figure 19: Pictured to the left is an undesirable littoral called Bulrush that is nonnative and grows very high and obstructs views (Autumn Woods Lake 9). Pictured to the right depict littorals taken over by torpedo grass with all vegetation having to be eliminated with chemical spraying. An algae bloom is also occurring. Littorals need to be maintained, so undesirable invasive exotic plants do not take over and create a vegetative monoculture that is unattractive (Autumn Woods Lake 9). It is important to plan the littoral plantings and then maintain them, both by replanting and controlling undesirables proactively. 19

20 c. Addressing/preventing point discharges i. Drainage pipe outfall repair options: One technique for repairing the point discharges caused by roof gutters includes removing the direct discharge into the lakes and creating an exfiltration aka French drain system that filters the stormwater through the ground. A French drain consists of perforated pipe that is buried in a rock trench that allows for percolation. Another technique to prevent erosion caused by the gutter pipes is to extend the pipes and establish a headwall under submerged conditions, even in the dry season. By discharging directly into the water and with a headwall, a less erosive condition is the result. This technique does not offer any pretreatment to the stormwater, though. Figure 20: Pictured above is a cross section of an exfiltration system aka French Drain. A perforated pipe is surrounded by aggregate (stones) and then wrapped in filter fabric. This system allows the stormwater infiltrate and be filtered by the surrounding soil. 20

21 Figure 21: Pictured above are various headwall treatments available for small diameter pipes to prevent scour and weigh down the pipe where they may discharge directly into a lake. 21

22 ii. Gutters and rain gardens Figure 22: Pictured to the left is a typical gutter system where the downspouts are directed to the driveway and the water goes directly to roadway gutters and into the lake via storm sewer pipes. Note the brown areas in the lawn. Figure 23: Pictured to the right is an alternative gutter system where the downspouts are directed to the yard, or to an exfiltration system allowing the stormwater to be filtered through the soil prior to entering the lake system as groundwater. Figure 24: Pictured above are two examples of rain gardens. The one to the left is between two homes. The one to the right is depicted just after a rainfall where the water has temporarily collected from the adjacent parking area. 22

23 4. Lake Water Quality a. Types of Pollutants in Stormwater Runoff: Table of Pollutants in Stormwater Runoff Pollutant Source Impact to Water Body Sediments Eroding rock, soil, or organic material from building sites, streets, and lawns Clogged waterways, increased turbidity, and reduction of bottom living organisms Nutrients Nitrogen and phosphorous from landscape runoff, atmospheric deposition, and faulty septic tanks Unwanted growth of algae and undesirable aquatic weeds, scum, and water discoloration Heavy Metals Lead, cadmium, chromium, copper, mercury, and zinc from vehicles, highway materials, Disruption of fish reproduction, fish toxicity, and potential for ground water contamination atmospheric deposition, and industry Oxygen Demanding Substances Decaying organic matter Death of fish and aquatic life forms Petroleum Hydrocarbons Pathogens Toxics Others Oil, grease, and various hydrocarbons from roads, parking lots, leaking storage tanks, and improper oil disposal Coliform bacteria and viruses from animal waste, septic systems, sewer cross-connections, and boats and marinas Pesticides, solvents, and chemicals from lawns, gardens, and commercial and household activities Changes in the temperature or physical properties of water Toxicity to aquatic life and adverse impacts on benthic communities Contamination of swimming, fishing areas, or drinking water Interference with respiration of fish and aquatic life forms Increased oxygen demand by fish and aquatic life forms and increased availability of toxic elements that harm organisms b. Causes of Algae Blooms are Nutrients: Nitrogen (N) and phosphorus (P) are generated from landscape runoff (fertilizers, detergents, plant debris), atmospheric deposition, animal wastes and defective septic systems. In excess, these nutrients increase biological productivity and may cause uncontrolled growth of algae and undesirable aquatic weeds. Figure 25: Pictures of algae blooms caused by high N and P from stormwater runoff in a lake in SW FL. The picture on the left is a view across the lake severely impacted by algae and pictured to the right is a close up of the floating algae. 23

24 Figure 26: Pictured to the left is an explanation of the three numbers used to describe fertilizer, which are Nitrogen (N), Phosphorous (P), and Potassium (K). The first two numbers N and P are what commonly contribute to algae blooms in lakes from excess fertilizer. Pictured to the right is an actual bag of fertilizer. High in N not desired, but is slow release. Zero in P, which is desired. c. Ways to Prevent Algae Blooms is to Prevent Nutrient Loadings as Follows: Use properly licensed and certified landscape maintenance companies. Use fertilizer application rates recommended by the Florida Friendly Best Management Practices for protection of Water Resources. Limit Nitrogen and Phosphorus usage to minimum recommended. Use slow release fertilizer. Respect the fertilizer ban periods or prior to major storm events. No fertilization within 10 feet of the water s edge. Use drought resistant plants. Our groundwater and reclaimed water might already have all the nutrients needed. Make sure grass clippings do not end up in the lakes. Riparian trees, avoid deciduous trees. 24

25 d. Techniques for Improving Water Quality Reducing and Removing Nutrients The picture above to the left is of two lakes on a cattle ranch, where the rancher allowed littoral plants to grow on the lake to the left and the one on the right littoral plants were not permitted to grow, resulting in a pea green appearance in the non vegetated lake. 25

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28 5. Program of Action a. Objectives/Goals: i. Flood protection ii. Erosion control iii. Improved aesthetics iv. Enhanced property values v. Efficient nutrient removal vi. Effective sediment removal vii. Provide food and habitat for wildlife 28

29 b. Budgeting/repair recommendations: i. Individual program tailored to each lake (Appendix B) Table of Pollutants and Suggested Ways to Address Pollutant Source Suggested Ways to Address Sediments Eroding rock, soil, or organic material from building sites, streets, and lawns Street sweeping program; Exfiltration. Roof gutters to yards, use of rain gardens. Nutrients Nitrogen and phosphorous from landscape runoff, atmospheric deposition Fertilizer guidelines in homeowners manual; littoral/buffer plants, floating islands, and aeration. Heavy Metals Oxygen Demanding Substances Petroleum Hydrocarbons Pathogens Toxics Others Lead, cadmium, chromium, copper, mercury, and zinc from vehicles, highway materials, and atmospheric deposition. Decaying organic matter Oil, grease, and various hydrocarbons from roads, parking lots, leaking storage tanks, and improper oil disposal Coliform bacteria and viruses from animal waste, septic systems, sewer cross-connections, and boats and marinas Pesticides, solvents, and chemicals from lawns, gardens, and commercial and household activities Changes in the temperature or physical properties of water Eliminate the use of copper sulfate as chemical application for treating algae. Exfiltration. Roof gutters to yards, use of rain gardens. Street sweeping program. Aeration, littoral plants, floating islands, restriction of deciduous and exotic trees around lakes encourage appropriate native trees. Education program. Exfiltration. Street sweeping. Education program (cross connections, exotic animals i.e. Muscovy Ducks) Education program. Eliminate the use of copper sulfate as chemical application for treating algae. Aeration to mix water column. Littoral plantings. ii. Multi year solution (3 5 years) iii. Cost Effective Shoreline Restoration (re grade shore line/geo web point areas) iv. Repair/retrofit gutter discharges into lakes (headwall) v. Littoral planting program (entire length of shoreline) vi. Aeration ( bubble diffusers) vii. Floating islands (not in initial budgets) viii. Maintenance of littorals and lake water with minimal chemical usage ix. Establish a street sweeping program (not in initial budgets) x. Eliminate use of Copper Sulfate long term as an algae treatment method 29

30 c. Education Homeowners Manual Update and Outreach i. Gutter and downspout recommendations/details (exfiltration/headwall). ii. Groundcover recommendations (sod alternatives) for buffer zone. iii. Littoral and tree plantings list. Appropriate plants. iv. Rain garden detail/planting suggestions. v. Fertilizer recommendations. vi. Exotic animals (do not attract/feed Muscovy ducks). vii. Summary of Pollutant Removal Program: Pollutant Source Suggested Ways to Address Sediments Eroding rock, soil, or organic material from building sites, streets, and lawns Street sweeping program; Exfiltration. Roof gutters to yards, use of rain gardens. Nutrients Nitrogen and phosphorous from landscape runoff, atmospheric deposition Fertilizer guidelines in homeowners manual; littoral/buffer plants, floating islands, and aeration. Heavy Metals Oxygen Demanding Substances Petroleum Hydrocarbons Pathogens Toxics Others Lead, cadmium, chromium, copper, mercury, and zinc from vehicles, highway materials, and atmospheric deposition. Decaying organic matter Oil, grease, and various hydrocarbons from roads, parking lots, leaking storage tanks, and improper oil disposal Coliform bacteria and viruses from animal waste, septic systems, sewer cross-connections, and boats and marinas Pesticides, solvents, and chemicals from lawns, gardens, and commercial and household activities Changes in the temperature or physical properties of water Eliminate the use of copper sulfate as chemical application for treating algae. Exfiltration. Roof gutters to yards, use of rain gardens. Street sweeping program. Aeration, littoral plants, floating islands, restriction of deciduous and exotic trees around lakes encourage appropriate native trees. Education program. Exfiltration. Street sweeping. Education program (cross connections, exotic animals i.e. Muscovy Ducks) Education program. Eliminate the use of copper sulfate as chemical application for treating algae. Aeration to mix water column. Littoral plantings. 30

31 APPENDIX A: SFWMD LETTER OF NON COMPLIANCE (3 Pages) 31

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34 APPENDIX B: SAMPLE BUDGETED IMPROVEMENT PROGRAM (11 Pages) i. Individual Lake Budgeted Improvement Program: a. Lake Number (1 thru 20). b. Pipe improvement cost estimate (exfiltration, hdwl, lf, cost) Pipe treatment and headwalls. See Estimate. c. Lake Bank Restoration Techniques (Type,area, cost) Regrade, geoweb and littorals. d. Littoral Planting Estimate (Area, cost) See Estimate. e. Aeration (bubblers, cost) See Estimate. f. Floating island (area, cost) Not proposed at this time. ii. Community Wide Street Sweeping (recommended frequency/cost) Not proposed at this time. iii. Lake Maintenance Program (water treatment and littoral maintenance, cost). Maintenance estimate provided. iv. Recharge well(s) for irrigation (permitting, construction, cost) Not proposed at this time. v. Comparison of Alternatives: a. Incremental implementation Address pipe improvements, geoweb, regarding, geoweb and aeration on an annual basis. Either address one lake at a time, or one improvement technique based on available funds. Fund over a 5 to 7 year period. b. Single project improvement Address improvements as a single project and then finance over a 7 year period. vi. Recommended Program Recommend addressing improvements as a single project to maximize community benefit and effectiveness of improvements. 34

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45 APPENDIX C: Conceptual Project Schedule (1 Page) i. Project Development (3 months): a. Committee Recommendations, Community Presentations and Board Approval b. Select Engineer and Construction Manager to Create Engineering Details and Bid Tabulation. c. Bid out Project Improvements (Pipe Improvements, Grading, Littoral Plantings and Aeration) and Select Construction Team. Finalize budget, project costs. d. Secure Financing. e. Coordination with SFWMD and Collier County. ii. Construction Improvements (9 to 12 months): a. Pipe Improvements. b. Grading. c. Littoral Plantings. d. Aeration. e. Liner Repairs. 45

46 APPENDIX D: FIGURE/ILLUSTRATION CREDITS (1 Page) i. Serge Thomas, Ph.D. FGCU, Preventing and dealing with pond eutrophication, Pond algae: why the populations fluctuate?, Presentation at Pelican Bay Foundation, October ii. Michael Bauer, Ph.D, Natural Resources Manager, City of Naples, Rain Gardens Presentation, iii. Robert Wright, Sarasota County Public Utilities, Living on the Water s Edge, A Neighborhood Approach to Stormwater Management, Presentation at Pelican Bay Foundation, October iv. Chad Washburn, Director of Conservation and Education, Naples Botanical Garden, Your pond s littoral zone and the environment, Presentation at NBG, November v. Mark Clark, Wetlands and Water Quality Extension Specialist, Soil and Water Science Department, University of Florida, Addressing Nutrient Sources not just Symptoms: A more Sustainable Approach to Stormwater Pond Management. vi. Martin B. Main, Ginger M. Allen, and Ken A. Langeland, University of FL IFAS, Creating Wildlife Habitat with Native Florida Freshwater Wetland Plants. vii. Autumn Woods SFWMD Permit Drawings, 1990 s. viii. SFWMD Best Management Practices Manual, April