Septic Systems: A brief overview

Collection systems

Countywide S2S Ranking• Methodology• Results• Examples• Nitrogen Loading• Current Projects

Moving forward/next steps• County Goals• Next Steps

Other programs in the Treasure Coast

Outline

~ Dry deposit Ton

Figure 7. Nitrogen sources and pathways to streams, including direct discharges, runoff, leaching to groundwater~ subsurface t ile drainage to dit ches, and precipitation d irectly into waters.

Nit rogen in M innesota Surface Waters • June 20 13 M innesota Pollut ion Control Agency

Septic System Fact:There were four (4) major changes to the criteria for septic system placement, requirements andsize of systems:Four significant periods of septic regulations*o Rules Prior to ‘72o Change: ’72 to ‘82o Change: ’83 to ’97o Change: ’98 to present*(Chapter 64E‐Florida Administrative Code, Standards for On‐site Sewage Treatment andDisposal Systems, 3/98)

Locations of Septic Tanks in Indian River County30,369 septic systems in Indian River County

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Jurisdiction Parcel with No Sewer Service Parcel Count %City of Fellsmere No Sewer Service, Built 1983 or After 648

No Sewer Service, Built Before 1983 464 4%

City of Sebastian No Sewer Service, Built 1983 or After 6,807No Sewer Service, Built Before 1983 1,577 28%

City of Vero Beach No Sewer Service, Built 1983 or After 486No Sewer Service, Built Before 1983 1,000 5%

County No Sewer Service, Built 1983 or After 11,419No Sewer Service, Built Before 1983 7,814 63%

Town of Indian River Shores No Sewer Service, Built 1983 or After 93No Sewer Service, Built Before 1983 60 <1%

Town of Orchid No Sewer Service, Built 1983 or After 1 <1%

Total 30,369

Data SourcesIndian River County Utility Dept, 2013City of Vero Beach Utility Dept, 2013Indian River County Property Appraiser, 2013

Indian River County Utility Department Service Area• Excluding COVB, Fellsmere, Town of IRS

325 Subdivisions/ Communities

Initial Ranking…”Importance Factor” Weighting

Final Ranking

Initial RankingSeven (7) Factors and associated Index Numbers

Index NumberFactor Min. Max.Population Density 4(x1*)= 4 12(x2*)= 24Proximity to Surface Waters 0.1(x1*)= 0.1 12(x2*)= 24FEMA Flood Plain 0 12Depth to Ground Water Table 4 12Soil Condition 4 12Age Surface Water Mgmt System 4 12Age of Existing OSTDS 4 12

20.1 to 108* 1 is minimum importance factor, and 2 is maximum importance factor

Importance Factor Weighting

Description (Distance to Nearest surface water) Factor• Adjacent to Indian River Lagoon (IRL) 2.0• Adjacent to Sebastian River (SR) 1.85

• Adjacent to and downstream of spillways for IRFWCD Main, North or South relief canals or other streams/channels within 1 mile of IRL 1.85

• Adjacent to and downstream of spillways for IRFWCD Main, North or South relief canals or other streams/channels within 1 mile of SR

• Adjacent to and within 1 mile upstream of spillways for IRFWCD Main, North or South relief canals or other streams from 1-2 miles of the IRL

1.7

1.4

• Adjacent to and within 1 mile upstream of spillways for SRID laterals Ca and L, and City of Sebastian waterways; or other Laterals (“C”), sub-laterals, streams / channels from 1-2 miles of the SR

1.3

• Adjacent to all other upstream surface waters 1.0

“Adjacent to” a surface water shall include any community within 100 ft. of a surface water

Population Density

Population Density Index #

x Importance

Factor Score

≤ 2 units/ac 4 x I 4 to 8

2 to 4.8 units/ac* 4 to 12* x I 4 to24

> 4.8 units/ac 12 x I 12 to 24*Sliding Scale, Index Number = 2.85d – 1.7

D = Density ( 2-4.8)I = Importance Factor (1.0 to 2.0)

Flood Zone Designation

Flood Zone Designation Index # / ScoreOutside 100 year Flood Hazard Area (FHA) 0

<= 1/3 community in FHA 4

1/3 to 2/3 of community in FHA 8

In Flood Zone 12

Depth to Groundwater Table

Depth to Groundwater Table (GWT) Index # / Score

> 48 inches 4

36 to 48 inches 5

24 to 36 inches 6

0 to 23 inches 10

above GWT 12

Soil Condition

Soil Description Index # / Score*

Slight (Slightly limited) 4

Moderate (Moderately limited) 5

Severe (Severely limited) 6

* Actual Score = calculate a weighted average number based on percentage of each soil classification within each community

Age of Surface Water Management System

Age of Stormwater Mgmt. System (yr) Index # / Score

After 2008 2

1999 to 2008 4

1982 to 1998 6

Before 1982 12

Age of Existing OSTDS (septic system)

Age of OSTDS/ Septic system Index # / Score

1998 to present 4

1983 to 1997 6

1972 to 1982 10

Before 1972 12

Example of an Initial Ranking CalculationSubdivisions Picked: Floravon Shores Sebastian Highlands Unit 05 River Shores Estates Units 1-4

Map Id. No Subdivision Name Importance

Factor

Population Density Index #

Proximity of Surface

Water Index #

Flood Plain Index #

Depth to Groundwater Index #

Soil Condition

Index #

Age of Surface Water

Management System Index #

Age of Existing OSTDS Index # Overall Score Initial

Ranking

48 Floravon Shores Subdivision 2.00 9.33 18.24 8.00 10.00 12.00 12.00 6.00 75.57 7

58 Sebastian Higlands Unit 05 1.70 12.30 16.66 0.00 10.00 12.00 12.00 6.00 68.96 12

320 River Shores Estates Units 1-4 2.00 14.36 8.56 4.00 10.00 12.00 12.00 10.00 70.92 10

S2S Methodology

Factors used in the Initial Ranking• Population Density - Importance factor assigned• Proximity to Surface Waters – Importance factor assigned• Flood Plain• Depth to Ground Water Table• Soil Condition• Age of Surface Water Management System• Age of the Existing OSTDS

Map Id. Subdivision Name Overall Score Initial Ranking

138 Hobart Landing Unit 2 89.19 117 Orchid Island No. 1 85.49 218 Orchid Island No. 2 84.65 3

139 Hobart Landing Unit 3 82.37 42 Hallmark Ocean Subdivision 78.45 51 Ambersand Beach Sub No 1 & 2 75.73 6

48 Floravon Shores Subdivision 75.57 7

131 Naranja TR Shellmound Bch Replat of POR 74.05

8

52 Sebastian Highlands Unit 02 Collier 73.05 9320 River Shores Estates Units 1-4 70.92 10212 Rain Tree Corner Subdivision 69.63 1158 Sebastian Highlands Unit 05 68.96 12

137 Hobart Landing Unit 1 68.28 1319 Orchid Isle Estates Subdivision 68.27 14

275 Amos (A of E) ** 67.51 15213 Kanawah Acres 67.41 16199 Verona Estates Subdivision 67.38 17291 Indian River Heights Units 1 -9 66.96 18273 Diana Park Subdivision 66.85 1949 Dales Landing Subdivision 66.33 20

278 Stevens Park Unit 1 & 2 66.17 21272 Pine Tree Park Units 1-4 65.24 22196 Little Portion Subdivision Replat OF 64.85 2350 Sebastian Highlands Unit 01 63.99 2457 Sebastian Highlands Unit 04 63.78 25

143 Winter Grove Subdivision 62.82 26207 Tropic Colony Subdivision 62.60 2732 Halleluiah Acres 62.50 2868 Sebastian Highlands Unit 13 62.30 2951 Sebastian Highlands Unit 02 62.09 30

INITIAL RANKING:Study evaluated 325 platted subdivisions within unincorporated IRC and City of Sebastian for the initial ranking.

Final Ranking

Re-prioritization of Initial Top 30

Sewer Cost per home – ascending order

Nitrogen reduction cost – ascending order

Presence of potable water

FINAL RANKINGInitial Rankings were then sorted per the following factors to obtain the Final Ranking:• Sewer Cost/home site – ranked in ascending order of

cost• Nitrogen reduction cost – ranked in ascending order of

cost• Presence of potable water

The top 30 ranked communities from Part 1 have been re-evaluated based on the cost of pollutant reduction, presence of potable water, and cost of sewer system construction, and re-prioritized based on these Factors:

• Initial ranking of the top 30 communities Already computed-Previous slide • Sewer cost per home site – ranked in ascending order of cost• Nitrogen reduction cost – ranked in ascending order of cost• Presence of potable water

The formula used to re-prioritize the communities was the sum of the ranking of above listed Factors, and an adjustment was made to the sum due to the presence of potable water. The results of the Capital Improvement Program Prioritization are provided on Table 9. – “Capital Improvement ProgramPriority Recommendation Summary”.

Map Id. No Subdivision Name Initial Ranking

Final Ranking Ssytem Type

Pollutant Reduction

lb/yr lb/yr/lot48 Floravon Shores Subdivision 7 1 Gravity 949.44 26.37

52 Sebastian Highlands Unit 02 Collier 9 2 Vacuum 1,027.53 36.70

58 Sebastian Highlands Unit 05 12 3 Vacuum 13,577.22 29.20138 Hobart Landing Unit 2 1 4 Gravity 965.00 37.1218 Orchid Island No. 2 3 5 Low Pressure 737.76 33.5357 Sebastian Highlands Unit 04 25 5 Vacuum 10,018.99 22.8717 Orchid Island No. 1 2 7 Low Pressure 473.15 33.801 Ambersand Beach Sub No 1 & 2 6 8 Gravity 2,802.36 33.36

50 Sebastian Highlands Unit 01 24 8 Vacuum 17,256.07 22.8956 Sebastian Highlands Unit 03* 31 10 Vacuum 1,580.57 9.41

131 Naranja TR Shellmound Bch Replat of POR 8 11 Low Pressure 326.94 29.72

51 Sebastian Highlands Unit 02 30 11 Vacuum 17,845.33 16.9619 Orchid Isle Estates Subdivision 14 13 Vacuum 2,428.71 36.25

139 Hobart Landing Unit 3 4 14 Low Pressure 270.20 38.60

53 Sebastian Highlands Unit 02 Replat PG 2* 38 14 Vacuum 1,268.19 19.22

320 River Shores Estates Units 1-4 10 16 Vacuum 1,663.11 13.86272 Pine Tree Park Units 1-4 22 17 Vacuum 6,221.58 11.85291 Indian River Heights Units 1 -9 18 17 Vacuum 5,759.18 7.46

54 Sebastian Highlands Unit 02 Replat PG 3* 45 17 Vacuum 3,319.68 25.73

212 Rain Tree Corner Subdivision 11 20 Low Pressure 444.68 27.79273 Diana Park Subdivision 19 21 Low Pressure 587.62 27.98199 Verona Estates Subdivision 17 22 Low Pressure 105.88 9.6368 Sebastian Highlands Unit 13 29 22 Vacuum 5,988.17 9.64

278 Stevens Park Unit 1 & 2 21 24 Vacuum 1,657.82 5.4749 Dales Landing Subdivision 20 24 Low Pressure 169.33 24.19

275 Amos (A of E) ** 15 24 Low Pressure 46.71 23.352 Hallmark Ocean Subdivision 5 24 Low Pressure 115.80 38.60

137 Hobart Landing Unit 1 13 24 Gravity 136.40 8.02143 Winter Grove Subdivision 26 29 Low Pressure 632.10 24.31213 Kanawah Acres 16 29 Low Pressure 164.70 13.73207 Tropic Colony Subdivision 27 31 Gravity 1,114.80 7.6932 Halleluiah Acres 28 32 Low Pressure 231.60 38.60

196 Little Portion Subdivision Replat OF 23 33 Low Pressure 201.17 9.58

55 Sebastian Highlands Unit 02 Replat PG 4* 69 34 Vacuum 893.08 15.95

136 Heritage Trace at Hobart * 281 35 Gravity 0.00 0.00

SBS Estimation of Nitrogen Loading

• Nitrogen• Soluble in water• Not readily removed

• Drainfield• Septic system converts organic nitrogen/ammonia

to nitrate• Removes 10% to 40% of nitrate

• Effluent Plume• Up to 20% additional removal of nitrate through soil• Dilution/dispersion reduces to drinking water

standard (< 10 mg/l) given enough travel time and distance

• Studies show effluent plumes extend well beyond expectations (N > 10 mg/l)

• 426 ft (N > 10 mg/l)• 1338 ft (detectable viruses)

N Load per Household (2.5 persons) % Reduction

ConcentrationMg/l

Loadlb/yr

From Household 70.0 52.8 0%

After Drainfield

0 to 165 ft 50.97 38.6 27%

165 to 657 ft 12.92 9.78 81%

> 657 ft < 10 7.55 > 85%

Treatment via Standard Septic System and Drainfield(N Removed)

Reference % N Removed

Sayemuzzaman, 2015 30%

USEPA (1992) 10 – 40%

USEPA (2002) [Anderson, 1994] 50% (estimate)

USEPA (2002) [Siegrist, 2001] 10 – 20%

Estimation of Nitrogen Loading from Raw Sewage per Household

Reference N Load per household

(mg/l) (lb/yr)

Sayemuzzaman, 2015 35.0 26.4

USEPA (1992) 45.0 – 55.0 34.0 – 41.5

USEPA (2002) [Anderson, 1994] 19.0 – 53.0 14.3 – 40.0

USEPA (2002) [Siegrist, 2001] 40.0 – 100.0 30.1 – 75.5

Estimation of Nitrogen Loading into Groundwater from Drainfield• Nitrogen loadings per household (lb/yr) from septic system drainfield to groundwater.

Reference Site Location N Load per household

(mg/l) (lb/yr)

Koppelman, 1978 Long Island, NY 16.8 12.7

Gold, et al., 1990 Kingston, RI 23.3 17.6

Weiskel and Howes, 1991 Buzzards Bay, MA 11.7 – 19.7 8.8 – 14.9

Maizel, et al. 1997 Chesapeake Bay 17.5 – 25.6 13.2 – 19.3

Valiela, et al., 1997 Waquoit Bay, MA 21.2 16.0

Reay, 2004 Coastal Plain, VA 17.5 – 21.2 13.2 – 16.0

Roeder, 2008 Wekiva, FL 23.0 17.4

Sayemuzzaman, 2015 St. Lucie Estuary, FL 24.5 18.5

USEPA (1992) N/A 35.8 – 65.6 27.0 – 49.5

USEPA (2002) [Anderson, 1994] N/A 21.6 16.3

USEPA (2002) [Siegrist, 2001] N/A 32.0 – 90.0 24.2 – 68.0

Wekiva Study (Ursin & Roeder, 2007) Central Florida N/A 30

CURRENT PROJECTS North Sebastian Septic to Sewer-

Phase IConstruction Phase- Pending approvalof assessment

North Sebastian Septic to Sewer-Phase II

Design 90% Complete

Moving Forward/Next StepsCounty Goals Protecting Our Lagoon

Work with the regulatory agencies, residents and other stakeholders to develop and implement the County Wide S2S plan

Provide safe, reliable water and wastewater service

Pursue grant dollars to minimize the overall impact to rate payers and be fair to all County citizens

Moving Forward/Next StepsNext Steps Approve Countywide Septic to Sewer Ranking by adopting the report

prepared by Schulke, Bittle & Stoddard, LLC. Work with Community Development Long Range planning staff to

incorporate the findings into the IRC 2030 Comprehensive Plan Chapter 3A, Sanitary Sewer Sub-Element for BCC review and approval at a later date.

Make the report available on-line.

Phase II : Proposed changes to the county comprehensive planPhase III : Financing options and public outreachPhase IV : Encumber funds and implementation of the priority

ranking plan