HomeMy WebLinkAboutSW5221001_Design Calculations_20230609 (2)
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Project Information
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SNAP v4.2.0
L O C A T I O N
Project Name (optional): ƒƭƷĻğķ {ƷğƷĻ tğƩƉ Parcel ID (optional):
ķğƷĻ
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Submission Date (optional):Nutrient Management Watershed:bĻǒƭĻ
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Local Jurisdiction / Reviewing Agency:{ƷğƷĻΉCĻķĻƩğƌ Subwatershed:bĻǒƭĻΏ ƦƦĻƩ
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Project Latitude Coordinates (optional):b Phosphorus Delivery Zone:bĻǒƭĻ Ώ ƦƦĻƩ ЉЌЉЋЉЋЉЊ
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Project Longitude Coordinates (optional): Nitrogen Delivery Zone:bĻǒƭĻ Ώ ƦƦĻƩ ЉЌЉЋЉЋЉЊ
P R O J E C T D E T A I L S
Ћ
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ŅƷ
Development Land Use Type:LƓƭƷźƷǒƷźƚƓğƌ Disturbed Area:ЌБАͲАЉЉ
y/nmenu
Part of Common Development Plan?Ɠƚ Project Activity:wĻķĻǝĻƌƚƦƒĻƓƷ
y/ny/n
Designated Downtown Area?Ɠƚ Project Drains to SA Waters?Ɠƚ
y/nmenu
Public Linear Road/Sidewalk Project?Ɠƚ Pre-Project Land Use:ŅƚƩĻƭƷ
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Project Owner Type:{ƷğƷĻ ƓƚƓΏb/5hProject Description (optional):
S T O R M W A T E R D E T A I L S
%y/n
(Falls ONLY) Onsite Reduction % Req.Project Uses LID/Runoff Volume Match?Ɠƚ
y/ny/n
Existing BUA/Development Onsite?Local Gov't nutrient req's same as State?ǤĻƭ
ķğƷĻ
y/n
Local Gov't cutoff date for Existing BUA:Project Drains to Regional SCM?Ɠƚ
ƌĬΉğĭΉǤƩƌĬΉǤƩ
Nitrogen Export Rate Target:Ќ͵ЏЉ Total Nitrogen Offset Credits Needed:
ƌĬΉğĭΉǤƩƌĬΉǤƩ
Phosphorus Export Rate Target:Total Phosphorus Offset Credits Needed:
SNAP v4.2.0
tƩĻĭźƦźƷğƷźƚƓ
Raleigh
Project Area and Offsite Land Cover Characteristics
{ƷğƷźƚƓʹ
/ƌźĭƉ ŷĻƩĻ Ʒƚ ƭĭƩƚƌƌ ķƚǞƓ Ʒƚ ĻƩƩƚƩ ƒĻƭƭğŭĻƭ ƚƓ Ʒŷźƭ ƭŷĻĻƷ͵
Copy & Paste VALUES ONLY for Best Results
22 2
PROJECT AREA LAND COVERSb 9a/ ΛƒŭΉ\[Μt 9a/ ΛƒŭΉ\[Μ
Pre-Project Area (ft)Post-Project Area (ft)Change pre-to-post (ft)
Roof Њ͵ЊБЉ͵ЊЊ 1,900
ЊͲЊЉЉЌͲЉЉЉ
Roadway Њ͵ЏЍЉ͵ЌЍ 0
Њ͵ЍЋЉ͵ЊБ 6,000
Parking/Driveway/Sidewalk ЊАВͲЏЉЉЊБЎͲЏЉЉ
Protected Forest Љ͵ВАЉ͵ЉЌЏͲЋВЋͲЍЉЉЏͲЋБЍͲЎЉЉ-7,900
Managed Pervious/Landscaping Ћ͵ЍБЊ͵ЉА 0
Offsite or Existing Roof Њ͵ЊБЉ͵ЊЊ 0
Њ͵ЏЍЉ͵ЌЍ 0
Offsite or Existing Roadway
Offsite or Existing Parking/Driveway/Sidewalk Њ͵ЍЋЉ͵ЊБ 0
Offsite Protected Forest Љ͵ВАЉ͵ЉЌ 0
Ћ͵ЍБЊ͵ЉА 0
Offsite Managed Pervious
CUSTOM LAND COVER 1 0
CUSTOM LAND COVER 2 0
CUSTOM LAND COVER 3 0
LAND TAKEN UP BY SCM Њ͵ЊБЉ͵ЊЊ 0
Total (Regulated & UnReg) Area
ЏͲЍАЌͲЊЉЉ͵ЉЉЏͲЍАЌͲЊЉЉ͵ЉЉ
Project (Regulated) Area
ЏͲЍАЌͲЊЉЉ͵ЉЉЏͲЍАЌͲЊЉЉ͵ЉЉ
SNAP v4.2.0
Nutrient Export Summary
Landcover & SCM Data Review
Errors / AdvisoriesErrors / Advisories
2
Avg Annual precip (in) =
46.220
SCM Area (ft) =
Total (Regulated +
2
6,473,1000
SCM Treated Area (ft) =
2
Unregulated) Area (ft) =
Project (Regulated)
Catchment Routing:
6,473,100No errors
2
Area (ft) =
Net BUA (Project Area
Treating Runoff from
Net BUA indicates new development or expansion.
7,900no
2
Existing BUA or Offsite:
BUA only ft) =
Custom Landcovers are
2
no387,700
Disturbed Area (ft) =
present:
Total Nitrogen Export Target Total Phosphorus Export Target
534.970.00
Scaled to Project Area (lb/yr):Scaled to Project Area (lb/yr):
Total Area Total Area Project Area Total Area Project Area Total Area Project Area
Project Area Total Area Project Area
(Onsite + Post-Project Post-Project Post-Project Post-Project Post-Project Post-Project
(Onsite Only) Post-Project Post-Project
Nutrient Export Summary
Offsite) before before SCM-Treated SCM-Treated Untreated Untreated
Pre-Projectafter Treatmentafter Treatment
Pre-ProjectTreatmentTreatmentArea OnlyArea OnlyAreasAreas
Area (All Landcover Types) (acres)
148.6019148.6019148.6019148.6019148.6019148.60190.00000.0000148.6019148.6019
Percent Built-Upon Area (BUA) (%)
3%3%3%3%3%3%0%0%3%3%
Built-Upon Area (BUA) (sqft)
180,700180,700188,600188,600188,600188,60000188,600188,600
3
1,685,7071,685,7071,710,3541,710,3541,710,3541,710,354001,710,3541,710,354
Annual Runoff Volume (ft/yr)
Annual Runoff % Change
1%1%1%1%
Total Runoff Change (cuft/yr)
24,64724,64724,64724,647
Total Nitrogen EMC (mg/L)
1.131.131.131.131.131.130.000.001.131.13
Total Nitrogen Load Leaving Site (lb/yr)
118.77118.77120.90120.90120.90120.90 0.000.00120.90120.90
ƚƷğƌ bźƷƩƚŭĻƓ \[ƚğķźƓŭ wğƷĻ ΛƌĬΉğĭΉǤƩΜ
0.800.800.810.810.810.810.000.000.810.81
Total Nitrogen % Change Pre-to-Post
2%2%2%2%
Total Nitrogen Change (lb/yr) Pre-to-Post
2.132.132.132.13
Total Phosphorus EMC (mg/L)
0.080.080.080.080.080.080.000.000.080.08
Total Phosphorus Load Leaving Site (lb/yr)
8.728.728.988.988.988.98 0.000.008.988.98
ƚƷğƌ tŷƚƭƦŷƚƩǒƭ \[ƚğķźƓŭ wğƷĻ ΛƌĬΉğĭΉǤƩΜ
0.060.060.060.060.060.060.000.000.060.06
Total Phosphorus % Change Pre-to-Post
3%3%3%3%
Total Phosphorus Change (lb/yr)Pre-to-Post
0.260.260.260.26
SCM/Catchment Summary
Volume TN Reduction TP Reduction b hǒƷ t hǒƷ
SCM ID and TypeFalls Lake ONLY: Onsite Reduction Compliance Check
Reduction (%)(%)(%)ΛƌĬƭΉğĭΉǤƩΜΛƌĬƭΉğĭΉǤƩΜ
Catchment 1
NitrogenPhosphorus
0.00%0.00%0.00%0.000.00
101: NA
Onsite % Reduction Requirement
0.00%0.00%0.00%0.000.00
102: NA
Export Target Scaled to Area (lb/yr)
0.00%0.00%0.00%0.000.00 534.97
103: NA
Export Load Post-Project Before Treatment
0.00%0.00%0.00%0.000.00 120.908.98
Total Reduction Need (lb/yr)
Catchment 2
0.00%0.00%0.00%0.000.00
201: NA
Onsite Reduction Need (lb/yr)
0.00%0.00%0.00%0.000.00
202: NA
Onsite Export Target (lb/yr)
0.00%0.00%0.00%0.000.00
203: NA
Project Area Post-Project After Treatment
0.00%0.00%0.00%0.000.00 120.908.98
0.00%0.00%0.00%0.000.00
Catchment 3
301: NA
0.00%0.00%0.00%0.000.00
302: NA
0.00%0.00%0.00%0.000.00
303: NA
0.00%0.00%0.00%0.000.00
Catchment 4
0.00%0.00%0.00%0.000.00
401: NA 0.00%0.00%0.00%0.000.00
402: NA
0.00%0.00%0.00%0.000.00
403: NA
0.00%0.00%0.00%0.000.00
Catchment 5
0.00%0.00%0.00%0.000.00
501: NA
0.00%0.00%0.00%0.000.00
502: NA
0.00%0.00%0.00%0.000.00
503: NA
0.00%0.00%0.00%0.000.00
Catchment 6
0.00%0.00%0.00%0.000.00
601: NA
0.00%0.00%0.00%0.000.00
602: NA
0.00%0.00%0.00%0.000.00
603: NA
0.00%0.00%0.00%0.000.00