HomeMy WebLinkAboutAppendix OAppendix
Response 3.2.23-
A -216
The purpose of this analysis is to approximate the amount of nitrogen reaching the Upper Glacial
aquifer that is attributable to the subject property.
Proiect Nitrogen Sources:
Nitrogen will be generated at the subject property from the following sources -
I. Sanitary wastewater from five residential homes using conventional sanitary system
treatment
II. Pet waste from the five residential homes
III. Irrigation water for the five residential homes
IV. Fertilization of turf grass at the five residential homes
V. Irrigation water for the farmland
VI. Fertilization of farmland
VII. Precipitation falling upon the total land area
Parameters for Analysis:
The following data extracted from the final "Suffolk County Subwatersheds Wastewater Plan"
dated July 2020 (unless otherwise noted) shall be used for the nitrogen budget analysis:
1. N released per person per year:
2. Nitrogen attenuation in septic tank:
3. Nitrogen attenuation in leaching pool effluent:
4. Leaching rate for residential turf fertilizer:
5. Leaching rate for agricultural fertilizer:
6. Nitrogen use for sweet corn & vegetables:
7. Nitrogen use for lawn fertilization:
8. Number of dogs per household:
9. Nitrogen load per dog:
10. Percent N in dog waste lost to volatilization:
10 lbs /person/year
6%
10%
30%
40%
80 lb. N /acre /year
2.04 lb. N /1,000 SF /year
1.4 dogs
4.29 lbs. /year
50%
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11. N from atmosphere leaching rate on natural vegetation: 25%
12. N from atmosphere leaching rate on turf: 30%
13. N from atmosphere leaching rate on agricultural land: 40%
14. N from atmospheric (wet and dry) deposition: 0.103 lbs. N /1,000 SF /year
15. Recharge from impervious surfaces as a percentage of precipitation': 80%
Notes:
• Gaseous loss of fertilizer is not included in this analysis, thus producing a more
conservative estimate of the nitrogen reaching the aquifer.
• Credit for potential denitrification within the aquifer is not included in this analysis,
thus producing a more conservative estimate of the nitrogen reaching the aquifer.
• For this analysis, cats were considered as indoor pets with litter box waste disposal,
and therefore do not contribute to the on -site nitrogen load.
• The nitrogen load associated with the agricultural use reflects implementation of
BMPs recommended by Cornell Cooperative Extension to mitigate fertilizer demand
while maximizing plant uptake.
Proiect Specific Data for Analysis:
The following data extracted from the DEIS and FEIS shall be used for the nitrogen budget
analysis:
a. Number of persons per household:
b. Number of residential households:
c. SF of residential turf grass:
d. SF of impervious land & bldgs.:
e. SF of other vegetated areas on residential land:
f. SF of planted crop land area:
g. SF of pervious agricultural land not planted:
2.3 [DEIS pg. 4 -8]
5 [DEIS pg. 4 -8]
71,874 SF [FEIS 3.2.8]
48,748 SF [DEIS pg. 1 -2]
111,119 SF [DEIS pg. 1 -2]
326,700 SF [FEIS App. S]
21,039 SF [FEIS App. S]
h. Existing concentration (avg.) of total N in groundwater 2: 9.25 mg /13 [DEIS App. N]
i. Turf grass irrigation water: 1,093,155 gals. [FEIS 3.2.8]
j. Ag irrigation water, minimum required: 0 gals. [FEIS app. S]
k. Ag irrigation water, average required:
1. Ag irrigation water, maximum required:
2,038,466 gals. [FEIS app. S]
3,486,368 gals. [FEIS app. S]
I Runoff coefficient for Rational Formula from table 3 -1 of "Hydraulic Engineering Circular No. 22, Third Edition ",
U.S. Department of Transportation Federal Highway Administration Publication FHWA- NHI -10 -009
2 Based on Nitrate and nitrite concentrations only, as established by the New York State Drinking Water standards
3 9.25 mg /l is equivalent to 0.000077195 lbs /gal
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Nitrogen Loading Calculations for Project as Proposed:
I. Calculation of N loading attributable to sanitary waste:
5 homes x 2.3 persons /home x (10 lbs. N /person/year) = 115 lbs. N per year (gross)
- Conventional Sanitary system consisting of septic tank and leaching pools causes
reduction of N loading as follows:
Septic tank effluent: 115 lbs N /year x 94% = 108.1 lbs /year
Leaching pool effluent: 108.1 lbs /year x 90% = 97.3 lbs /yr (net)
II. Calculation of N loading attributable to pet waste:
5 homes x 1.4 dogs/home x (4.29 lbs N /dog/year) x 50% volatilization loss =15.0 lbs /yr
III. Calculation of N loading attributable to residential turf grass fertilization:
71,874 SF x (2.04 lbs N /1,000 SF /yr) x 30% leaching rate = 44.0 lbs /yr
IV. Calculation of N loading attributable to atmospheric deposition on turf grass:
71,874 SF x (0.103 lbs. N /1,000 SF /year) x 30% leaching rate = 2.2 lbs /yr
V. Calculation of N loading attributable to atmospheric deposition on impervious surfaces:
48,748 SF x (0.103 lbs. N /1,000 SF /year) x 80% leaching rate = 4.0 lbs /yr
VI. Calculation of N loading attributable to atmospheric deposition on natural vegetation:
111,119 SF x (0.103 lbs. N /1,000 SF /year) x 25% leaching rate = 2.9 lbs /yr
Page 4
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VII. Calculation of N loading attributable to agricultural fertilization:
7.5 acres x (80 lbs N /acre /yr) x 40% leaching rate = 240 lbs /yr
VIII. Calculation of N loading attributable to atmospheric deposition on planted Ag land:
326,700 SF x (0.103 lbs. N /1,000 SF /year) x 40% leaching rate = 13.5 lbs /yr
IX. Calculation of N loading attributable to atmospheric deposition on non - planted Ag land:
21,039 SF x (0.103 lbs. N /1,000 SF /year) x 40% leaching rate = 0.7 lbs /yr
X. Calculation of N reduction attributable to irrigating turf grass: The proposed domestic
wells will draw water from the Upper Glacial aquifer laying beneath the subject property.
SCDHS groundwater quality testing demonstrates the groundwater lying beneath the site
has elevated concentrations of nitrogen. Fertigation is the process whereby a portion of
the nitrogen necessary for plant growth is provided by the irrigation water, as opposed to
fertilizer. As the nitrogen rich irrigation water is applied, a certain percentage of nitrogen
in the water will be consumed by the plant, with the remaining portion returning to the
aquifer below. A reduction in nitrogen in the aquifer can be realized through fertigation.
(1,093,155 gals /yr) x (0.000077195 lbs /gal) x 70 %4 N consumption rate = - (59.1 lbs /yr)
XI. Calculation of N reduction attributable to irrigating planted Ag land: The proposed
irrigation well will draw water from the Upper Glacial aquifer laying beneath the subject
property. SCDHS groundwater quality testing demonstrates the groundwater lying
beneath the site has elevated concentrations of nitrogen. Fertigation is the process
whereby a portion of the nitrogen necessary for plant growth is provided by the irrigation
water, as opposed to fertilizer. As the nitrogen rich irrigation water is applied, a certain
percentage of nitrogen in the water will be consumed by the plant, with the remaining
portion returning to the aquifer below. A reduction in nitrogen in the aquifer can be
realized through fertigation.
Minimum Irrigation Year-
(0 gals /yr) x (0.000077195 lbs /gal) x 60 %5 N consumption rate = - (0 lbs /yr)
a A 30% leaching rate applies to turf lawn
s A 40% leaching rate applies to agricultural land
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Average Irrigation Year-
(2,038,466 gals /yr) x (0.000077195 lbs /gal) x 60 %6 N consumption rate = - (94.4 lbs /yr)
Maximum Irrigation Year-
(3,486,368 gals /yr) x (0.000077195 lbs /gal) x 60 %7 N consumption rate =
- (150.5 lbs /yr)
Summary of Nitrogen Budget for proposed project during minimum Ag irrigation year:
Sanitary Waste
97.3 lbs /year
Pet waste
15.0 lbs /year
Turf lawn fertilization
44.0 lbs /year
Turf lawn atmospheric deposition
2.2 lbs /year
Impervious surface atmospheric deposition
4.0 lbs /year
Natural vegetation atmospheric deposition
2.9 lbs /year
Farmland fertilization
240 lbs /year
Farmland (planted) atmospheric deposition
13.5 lbs /year
Farmland (unplanted) atmospheric deposition
0.7 lbs /year
Turf lawn irrigation reduction
- (59.1 lbs /year)
Farmland irrigation reduction
- (0 lbs /year)
Total Nitrogen Load
+ 360.5 lbs /year
6 A 40% leaching rate applies to agricultural land
A 40% leaching rate applies to agricultural land
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Summary of Nitrogen Budget for proposed project during average Ag irrigation year:
Sanitary Waste
97.3 lbs /year
Pet waste
15.0 lbs /year
Turf lawn fertilization
44.0 lbs /year
Turf lawn atmospheric deposition
2.2 lbs /year
Impervious surface atmospheric deposition
4.0 lbs /year
Natural vegetation atmospheric deposition
2.9 lbs /year
Farmland fertilization
240 lbs /year
Farmland (planted) atmospheric deposition
13.5 lbs /year
Farmland (implanted) atmospheric deposition
0.71bs /year
Turf lawn irrigation reduction
- (59.1 lbs /year)
Farmland irrigation reduction
- (94.4 lbs /year)
Total Nitrogen Load
+ 266.1 lbs /year
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Summary of Nitrogen Budget for proposed project during maximum Ag irrigation year:
Sanitary Waste
97.3 lbs /year
Pet waste
15.0 lbs /year
Turf lawn fertilization
44.0 lbs /year
Turf lawn atmospheric deposition
2.2 lbs /year
Impervious surface atmospheric deposition
4.0 lbs /year
Natural vegetation atmospheric deposition
2.9 lbs /year
Farmland fertilization
240 lbs /year
Farmland (planted) atmospheric deposition
13.5 lbs /year
Farmland (implanted) atmospheric deposition
0.71bs /year
Turf lawn irrigation reduction
- (59.1 lbs /year)
Farmland irrigation reduction
- (150.5 lbs /year)
Total Nitrogen Load
+ 210.0 lbs /year
Page 8 A -223
Nitrogen Loading Calculations for 100% Farmland Use:
The subject site is agricultural land. As stated in the "Farmland Bill or Rights" contained in
section 280 -97 of the Town Code, the subject property could be fully developed solely for
agricultural use. The nitrogen analysis shown below illustrates the nitrogen budget for that as -of-
right development scenario:
Calculation of N loading attributable to agricultural fertilization:
12.55258 acres x (80 lbs N /acre /yr) x 40% leaching rate = 401.7 Ibs /yr
II. Calculation of N loading attributable to atmospheric deposition on planted Ag land:
546,787 SF x (0.103 lbs. N /1,000 SF /year) x 40% leaching rate = 22.5 lbs /yr
III. Calculation of N loading attributable to atmospheric deposition on non - planted Ag land:
32,693 SF x (0.103 lbs. N /1,000 SF /year) x 40% leaching rate = 1.31bs /yr
IV. Calculation of N reduction attributable to irrigating planted Ag land9: The proposed
irrigation well will draw water from the Upper Glacial aquifer laying beneath the subject
property. SCDHS groundwater quality testing demonstrates the groundwater lying
beneath the site has elevated concentrations of nitrogen. Fertigation is the process
whereby a portion of the nitrogen necessary for plant growth is provided by the irrigation
water, as opposed to fertilizer. As the nitrogen rich irrigation water is applied, a certain
percentage of nitrogen in the water will be consumed by the plant, with the remaining
portion returning to the aquifer below. A reduction in nitrogen in the aquifer can be
realized through fertigation.
Minimum Irrigation Year-
(0 gals /yr) x (0.000077195 lbs /gal) x 60 %10 N consumption rate = - (0 Ibs /yr)
8 It is estimated that three quarters of an acre of the total land area will be unplanted area
9 The crop irrigation water estimate is based on Appendix S of the FEIS. In that irrigation water estimate 7.5 acres of
land area was to be irrigated. For this analysis 12.5525 acres of land shall require irrigation, thus the irrigation water
demand shown in Appendix S of the FEIS shall be scaled up using a factor of 1.67.
10 A 40% leaching rate applies to agricultural land
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Average Irrigation Year-
(3,404,238 gals /yr) x (0.000077195 lbs /gal) x 60 %11 N consumption rate =
- (157.7 lbs /yr)
Maximum Irrigation Year-
(4,000,000 gals /yr) 12 x (0.000077195 lbs /gal) x 60 %13 N consumption rate =
- (185.3 lbs /yr)
1 A 40% leaching rate applies to agricultural land
12 Maximum yearly water pumpage based on current NYSDEC agricultural well permit
is A 40% leaching rate applies to agricultural land
Page 10
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Summary of Nitrogen Budget for 100% farmland use during minimum Ag irrigation year:
Farmland fertilization
401.7 lbs /year
Farmland (planted) atmospheric deposition
22.5 lbs /year
Farmland (unplanted) atmospheric deposition
1.3 lbs /year
Farmland irrigation reduction
- (0 lbs /year)
Total Nitrogen Load
+ 425.5 lbs /year
Summary of Nitrogen Budget for 100% farmland use during average Ag irrigation year:
Farmland fertilization
401.7 lbs /year
Farmland (planted) atmospheric deposition
22.5 lbs /year
Farmland (unplanted) atmospheric deposition
1.3 lbs /year
Farmland irrigation reduction
- (157.71bs /year)
Total Nitrogen Load
+ 267.8 lbs /year
Summary of Nitrogen Budget for 100% farmland use during maximum Ag irrigation year:
Farmland fertilization
401.7 lbs /year
Farmland (planted) atmospheric deposition
22.5 lbs /year
Farmland (unplanted) atmospheric deposition
1.3 lbs /year
Farmland irrigation reduction
- (185.3 lbs /year)
Total Nitrogen Load
+ 240.21bs /year