HomeMy WebLinkAboutSP-20-023 - Supplemental - 1200 Airport Drive (28)Version: 2/12/2020
Filters (4.3.4)
1
2
3
4
5
6*
7
* Questions preceded by an asterix (*) may change based on previously entered values
8*
9*
10
11*
12
13
14
15
16
17
18*
19
20
21
22
23*
24
25
26*
27*
28*
29*
30*
31
Attachment location: Indicate the specific location (i.e. appendix, page, plan sheet) where the requisite support documentation has been provided within the application.
Practice Drainage Area
New Impervious (acres)
Redeveloped Impervious
Design Volume for Infiltration TV (acre-feet)
Designed to Infiltrate >WQV?
Note: If the practice is designed to infiltrate the WQV, then TV = WQV. Designers may use the Practice Drainage Area Runoff Calculator (second tab) for calculation of practice-specific
runoff volumes for other treatment standards. Sizing of the filter bed area/swale bottom need to consider the desired treatment volume (see treatment section). Some design requirements
will change based on the size of storm the practice is designed to treat.
Feasibility (4.3.4.1)
Is the SHGWT at or below the bottom of the practice?
Conveyance (4.3.4.2)
Has an underdrain been provided? (required if the underlying soils have an infiltration rate of less than 0.2 inches per hour)
Has the underdrain been designed in conformance with Section 4.3.1.2?
Have the outfalls and the conveyance to the discharge point been designed/protected to avoid erosive velocities?
Is the practice unlined unless the presence of a stormwater hotspot or other site constraint has been discussed with ANR?
Pre-Treatment (4.3.4.3)
Has pretreatment been provided for non-rooftop runoff?
What type of pretreatment is being used?
Treatment (4.3.4.4)
Does the site plan specify a filter media consisting of medium sand (ASTM C-33 concrete sand) or an approved equivalent?
Does the filter bed have a minimum depth of 18 inches or 12 inches for perimeter filters?
Water Quality Volume Provided by STP
What is the Water Quality Volume that the Filter bed will be sized to treat?
What is the depth of the filter bed? (2-4 feet)
What is the coefficient of permeability of the filter media?
What is the average height of water above the filter bed?
What is the design filter bed drain time? (≤2 days)
Required minimum surface area of the filter bed
Design filter bed area
Is the Filter storage volume, including the storage volume above the filter bed, volume in any upstream pre-treatment practice, as well as within the filter media, > 75% of the design
WQv or Tv (as applicable)?
Treatment Volume Calculation- Bioretention with Underdrain
What is the surface area of the filter bed/ swale bottom?
What is the depth of media beneath the underdrain invert?
What is the porosity of the media beneath the underdrain invert?
Treatment Volume
Treatment Volume
Landscaping (4.3.1.5)
Does the site plan specify a landscaping plan that ensures dense and vigorous vegetation over the contributing pervious drainage areas and the practice?
Total Area (acres)
WQV to practice
Designed to Infiltrate?
For Permit Coverage
3.82
1.44
2.38
WQV for credit
0.221125
↑ WQv to enter in the Water Quality section under Tier 2&3 practices table. The practice may also receive Tv credit for sump storage below an underdrain (see Question 30)
0
Not for Permit Coverage
0
0
0
WQV not for credit
0
2
2
Total to Practice
3.82
1.44
2.38
Total WQV
0.221125
Project Name:
Discharge Point:
Filter #
Modified CN for WQ (1.0") storm
df (ft)
k (ft/day)
hf (ft)
tf (days)
Af (ft2)
Af (ft2)
Af (ft2)
(ft)
porosity
Tv
Tv
Burlington International Airport, Construct Remain Overnight Apron (Phase 7)
S/N 001
F1
Response
0
Response
Response
Response
Response
0.221125
2
10
5
1
275.205857142857
11157.35
Response
11157.35
2
0.4
8925.88
0.204910009182736
↑ Enter this value on the Standards Compliance Worksheet
Response
96.8625238234709
Attachment location
1
Attachment location
Attachment location
Attachment location
0
Attachment location
Attachment location
ft3
ac-ft
Attachment location
Practice Drainage Area Runoff Calculator
This tool may be used to calculate the required treatment volumes for the area draining to an individual practice where the practices drainage area is only a portion of of the area draining
to a discharge point. Where the practice receives runoff from the entire area to a discharge point, this calculator will give the same information as the Standards Compliance Workbook.
Precipitation Data
Storm
Precipitation (inches)
Drainage Area Information
Pre Development Land Use (acres)
Landuse
Grass
Meadow
Woods
Pavement, roofs, and other impervious
Total
Post Development Land Use (acres)
Landuse
Grass
Meadow
Woods
Pavement, roofs, and other impervious
Total
TV of upstream practices:
Treatment Standard
Channel Protection (Hydrologic Condition Method)
Overbank Flood
Extreme Flood
Information for Calculating TC by the Watershed Lag Method
Pre Development
Post Development, upstream of practice
Post Development, with TV credit from practice
* Preciptation values shall be obtained from
WQ Storm
1
Hydrologic Soil Group
A
0
0
0
0
0
Hydrologic Soil Group
A
0
0
0
0
0
0
Required Treatment Volume
0
0
0
Average Catchment Slope, Y (%)
0
0
0
1 yr, 24 hr
0
B
0
0
0
0
0
B
0
0
0
0
0
ac-ft
Post Development Runoff Volume
0
0
0
Hydraulic Length, l (ft)
0
0
0
10 yr, 24 hr
0
C
0
0
0
0
0
C
0
0
0
0
0
Pre-development Runoff Volume
0
0
0
Time of Concentration, TC (min)
1 yr
0
0
0
Project Name:
Discharge Point:
Filter #
NOAA Atlas 14
100 yr, 24 hr
0
D
0
0
0
0
0
D
0
0
0
0
0
TV credit of this practice:
Post Composite CN (to practice)
0
0
0
10 yr
0
0
0
Burlington International Airport, Construct Remain Overnight Apron (Phase 7)
S/N 001
F1
Total (acres)
0
0
0
0
0
Total (acres)
0
0
0
0
0
0
CNAdj (with TV practice credit)
0
0
0
100 yr
0
0
0
ac-ft
Pre Composite CN
0
0
0
Curve Numbers
Landuse
Grass
Meadow
Woods
Gravel/ Unpaved Roads
Pavement, Roofs, and other impervious
S=1000/CN - 10
Landuse
Grass
Meadow
Woods
Gravel/ Unpaved Roads
Pavement, Roofs, and other impervious (not gravel)
Recharge Factors
Hydrologic Soil Group
Recharge Factor
Hydrologic Soil Group
A
39
30
30
96
98
Hydrologic Soil Group
A
15.6410256410256
23.3333333333333
23.3333333333333
0.416666666666666
0.204081632653061
A
0.6
B
61
58
55
96
98
B
6.39344262295082
7.24137931034483
8.18181818181818
0.416666666666666
0.204081632653061
B
0.35
C
74
71
70
96
98
C
3.51351351351351
4.08450704225352
4.28571428571429
0.416666666666666
0.204081632653061
C
0.25
D
80
78
77
96
98
D
2.5
2.82051282051282
2.98701298701299
0.416666666666666
0.204081632653061
D
0