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Workshop – Water Quality Review July 1, 2013.  Purpose  Regulations  OSTDS Evaluation – East & West Spring lake  Sampling & Test Results  Other Contributors.

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Presentation on theme: "Workshop – Water Quality Review July 1, 2013.  Purpose  Regulations  OSTDS Evaluation – East & West Spring lake  Sampling & Test Results  Other Contributors."— Presentation transcript:

1 Workshop – Water Quality Review July 1, 2013

2  Purpose  Regulations  OSTDS Evaluation – East & West Spring lake  Sampling & Test Results  Other Contributors  Soils Data  Relevant Studies  Summary

3  Provide a summary of Water Quality Data collected within the East & West Spring Lake Area  Provide a summary of similar studies  Provide a summary of Regulations  Provide a correlation with Onsite Sewage Treatment and Disposal Systems (OSTDS)

4  62E-06, Florida Administrative Code ◦ OSTDS Regulations  , Florida Administrative Code ◦ Numeric Nutrient Criteria  Manchester Lock Permit

5  Provides requirements for OSTDS construction & repair  1983 standards changed ◦ Separation from seasonal high water table Increased from 12-inches to 24-inches ◦ Setback from water body Increased from 50-feet to 75- feet* ◦ Septic tank and drainfield sizes increased  Sizes dependent on structure size * Charlotte Code of Ordinances (3-7-56) restricts setback to 150-feet for tidally influenced water bodies

6  1983 standards changed ◦ Separation from seasonal high water table Increased from 12-inches to 24-inches ◦ Setback from water body Increased from 50-feet to 75-feet* ◦ Septic tank and drainfield sizes increased  Sizes dependent on structure size * Charlotte Code of Ordinances (3-7-56) restricts setback to 150-feet for tidally influenced water bodies

7 7 62E-06 REPAIR REQUIREMENTS Conventional Septic System

8 8 62E-06 REPAIR REQUIREMENTS CONT’D

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10  Set nutrient loading limitations for estuaries ◦ Arithmetic mean shall not to be exceeded more than once in a 3-year period Region Total Phosphorous Total NitrogenChlorophyll a 4. Charlotte Harbor Proper 0.19 mg/L0.67 mg/L6.1 µg/L

11  FDEP Permit ◦ “A Phased Sewer Expansion – include in the Charlotte County Sewer Expansion Plan those portions of the Alligator Bay Drainage Basin that have been shown to contribute to declining water quality (pre-1983 septic tanks)”

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13  1,708 recorded OSTDS’s in East/West Spring Lake  452 vacant lots  Buildout percentage = 80%  1,286 OSTDS (75.3%) installed prior to 1983

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16  Water level data was collected in East/West Spring Lake to determine water table relative to ground surface  To meet 24-inches of separation for current regulations, the seasonal high water table should not be within 3.5 feet of ground surface or below land surface (BLS )

17 ParameterJuneSeptemberNovemberJanuary Mean Water Level (BLS)*2.1 ft 3.1 ft3.9 ft Number of samples < 3.5 ft BLS Percentage < 3.5ft BLS80% 64%42% Groundwater Elevations in East & West Spring Lake * Based on mean water levels, it is estimated that the majority of the systems do not meet current or past separation requirements and some drainfields may be within the water table a portion of the year.

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20  Ordinance : Management of OSTDS  Since adoption (2007 to Present), 250 repairs have been made in East & West Spring Lake  Prior to adoption (1950s to 2007), 132 repairs had been made  When a failure occurs, regulations require OSTDS to meet current standards. If separation from seasonal high water table cannot be met, the replacement system must be elevated (mounded)

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22  More expensive  More maintenance / pump failure  Affects aesthetics  Difficult to maintain grounds  Limits use of property  Drainage problems  Special construction needs: ◦ Dosing chamber ◦ Pump ◦ Retention/landscape wall

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25  50+ wells installed throughout East & West Spring Lake  21 canal sample points within & upstream of East & West Spring Lake  Wells sampled and tested every 2 months ◦ Nitrogen ◦ Phosphorous ◦ Fecal Coliform ◦ Water levels

26 Jun/Jul 2012Sep/Oct 2012Jan/Feb 2013Mar/Apr 2013 Low0.004 mg/L High mg/L4.692 mg/L17.33 mg/L39.17 mg/L Water Table2.1 ft BLS 3.1 ft BLS3.9 ft BLS Average.605 mg/L0.184 mg/L0.743 mg/L1.02 mg/L Nitrogen Concentrations in East & West Spring Lake Jun/Jul 2012Sep/Oct 2012Jan/Feb 2013Mar/Apr 2013 Low.004 mg/L0.004 mg/L High0.033 mg/L0.062 mg/L0.033 mg/L0.038 mg/L Average0.021 mg/L0.03 mg/L0.013 mg/L0.012 mg/L Nitrogen Concentrations in Canal System

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31 Jun/Jul 2012Sep/Oct 2012Jan/Feb 2013Mar/Apr 2013 Low.02 mg/L0.02 mg/L0.11 mg/L0.15 mg/L High4.05 mg/L13.53 mg/L5.62 mg/L31.69 mg/L Water Table2.1 ft BLS 3.1 ft BLS3.9 ft BLS Average1.05 mg/L1.36 mg/L1.12 mg/L2.39 mg/L Phosphorous Concentrations in East & West Spring Lake Phosphorous Concentrations in Canal System Jun/Jul 2012Sep/Oct 2012Jan/Feb 2013Mar/Apr 2013 Low0.22 mg/L0.29 mg/L0.02 mg/L0.04 mg/L High0.66 mg/L0.52 mg/L0.32 mg/L0.42 mg/L Average0.42 mg/L0.41 mg/L0.18 mg/L0.23 mg/L

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36 Jun/Jul 2012Sep/Oct 2012Jan/Feb 2013Mar/Apr 2013 Low10 col/100 ml High2940 col/100 ml1720 col/100 ml10 col/100 ml Water Table2.1 ft BLS 3.1 ft BLS3.9 ft BLS Average123.5 col/100 ml44.9 col/100 ml10 col/100 ml Fecal Coliform Concentrations in East & West Spring Lake Fecal Coliform Concentrations in Canal System Jun/Jul 2012Sep/Oct 2012Jan/Feb 2013Mar/Apr 2013 Low10 col/100 ml High90 col/100 ml80 col/100 ml200 col/100 ml70 col/100 ml Average41.3 col/100 ml29.1 col/100 ml31.9 col/100 ml18.1 col/100 ml

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40  Nitrogen ◦ Range: mg/L to mg/L ◦ Drinking water limit: 10 mg/L ◦ NNC limit: 0.67 mg/L ◦ Wells closest to OSTDS had highest recordings ◦ Groundwater levels > canal levels ◦ Levels highest winter season when winter residents are present

41  Phosphorous ◦ Range: 0.02 mg/L to mg/L ◦ NNC limit: 0.19 mg/L ◦ In wells, 150 of 171 samples tested higher than the NNC limit (88%) ◦ In canals, 55 of 69 samples tested higher than NNC limit (80%) ◦ The average for all samples was mg/L, 5 x the NNC limit ◦ Wells closest to OSTDS had highest average recordings ◦ Groundwater levels > canal levels ◦ Levels highest in winter season when winter residents are present

42  Fecal Coliform ◦ Range: 10 col/100 ml to 2940 col/100 ml ◦ Multiple samples tested above 400 col/100, two (2) from the same well ◦ Canal levels > groundwater Levels ◦ Levels highest during wet Season when soils are saturated & filtration & adsorption is reduced due to high water table

43  Atmospheric ◦ Deposition of nutrients from atmosphere  Fertilizer ◦ Can result in application of nitrogen & phosphorous ◦ Restricted use (Ordinance )  No phosphorous application June 1 to September 30  < 4 lbs of nitrogen can be applied / yr / 1,000 sf  < 0.5 lbs of phosphorous can be applied / yr / 1,000 sf  Other (Animals, etc.)

44  Difference between OSTDS and other contributors ◦ Nutrients from other contributors are applied in the atmosphere and are largely taken in by plant life ◦ Nutrients from OSTDS are released below the ground and depend on soils for removal prior to entering groundwater

45  Matlacha Sands  Kesson Fine Sand  Pineda Fine Sand  Oldsmar Fine Sand  Common traits of soils in E/W Spring Lake ◦ Gravelly fine sand ◦ Poorly drained ◦ Unsuitable for drainfields ◦ Seasonal high water table within 10-inches BLS ◦ Kesson, noted as being located in tidal swamps subject to tidal flooding

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47  Charlotte Harbor & Estero Bay Aquatic Preserves Water Quality Status & Trends for ◦ Study reviewed water quality data within regions of Charlotte Harbor & Estero Bay ◦ Upper Charlotte Harbor results  Highest phosphorous levels of region  Highest single nitrogen recording  70 th Percentile of Florida estuaries for Phosphorous  80 th Percentile of Florida estuaries for Nitrogen  80 th Percentile of Florida estuaries for Fecal Coliform

48  Effects of Seasonal Variability on Microbial Fecal Pollution and Enteric Pathogens in a Subtropical Estuary ◦ 12 sample stations were set within Charlotte Harbor and sampled monthly for indicator bacteria ◦ 4 of the stations were located in the vicinity of East & West Spring Lake (East Spring Lake, West Spring Lake, Sunrise Waterway & Countryman Waterway) ◦ Of the samples tested, East & West Spring Lakes recorded the highest & 2 nd highest fecal levels ◦ Concentrations were highest during wet season

49  Groundwater System Water Quality Data Port Charlotte Area ◦ Study performed for the purpose of characterizing surface & groundwater quality in Port Charlotte ◦ 8 study sites selected within a 400 home area ◦ Monitoring wells installed to determine direction of groundwater flow and plume potential for nutrients from OSTDS to edge of lot lines ◦ Average nitrogen levels of mg/L at drainfield and 7.92mg/L at lot line ◦ Average phosphorous levels of mg/L at drainfield and at Lot Line

50  Several factors reviewed link OSTDS’s to decreased water quality in East/West Spring Lake: ◦ Soils unsuitable for OSTDS installation ◦ A seasonal high water table unsupportive of treatment ◦ A population density unfavorable for OSTDS ◦ Close proximity to canals ◦ Limited treatment capability of OSTDS ◦ Test results indicating positive correlation with nutrients & bacteria ◦ Studies indicating high nutrient & fecal levels in upper Charlotte Harbor, amongst the highest in the State

51  Based on findings and factors and given the age, number of past repairs and projection of future replacement, it is recommended that Charlotte County consider installation of a centralized sewer system  A Centralized Sewer System would: ◦ Eliminate dependence on OSTDS ◦ Eliminate future OSTDS failure and pollution ◦ Be a positive step towards cleaning the groundwater & surface water and in helping diminish the impairment of Charlotte Harbor


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