HomeMy WebLinkAboutSP-22-012 Taxiway A - Supplemental - 1200 Airport Drive (12)Version: 11/30/2020 Project Name:
Discharge Point:
Infiltration Practice #
Practice Drainage Area
For Permit
Coverage
Not for Permit
Coverage
Total to
Practice
1 Total Area (acres)2.770 0.216 2.986
2 0.430 0.000 0.430
3 0.060 0.000 0.060
WQV for
credit
WQV not for
credit
Total
WQV
4 WQV to practice 0.0518 0.0009 0.0527 87
5 0.3000
6
3
Response Attachment location
7 Soil Report
8*Soil Report
9 Soil Report
10 Soil Report
11 Plans
12 Soil Report
13*
0 1
Response Attachment location
Redeveloped Impervious
Design Volume for
Infiltration (TV)
Modified CN for WQ
(1.0") storm
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.
← Tv value to enter on the Standards Compliance Workbook for this
practice
Is the seasonal high groundwater table (SHGWT) separated at least three (3)
feet vertically from the bottom of the practice?
New Impervious (acres)
Rehabilitate Taxiway A
SN1
1Infiltration (4.3.3)
Feasibility (4.3.3.1)
Has the infiltration rate (fc) of the underlying soil been confirmed to be at least
0.2 inches per hour by the soil testing requirements in Section 4.3.3.2?
Practice Type
* Questions preceded by an asterix (*) may change based on previously entered values
Has a groundwater mounding analysis been performed if the practice is
designed to infiltrate >1 year storm and the SHGWT <4 feet?
1
Have the proper setback requirements for groundwater source protection been
observed? (Section 4.3.3.1)
Has the practice been placed so that it will not cause intrusion problems for
down-gradient structures? (Section 4.3.3.1)
Is the site free from subsurface contamination or prior approval obtained from
the Agency? (If approval is required based on prior contamination, include
Conveyance (4.3.3.2)
Yes No
NoYes
NoYes
Infiltration Basin
Infiltration Trench
Infiltration Chambers
Drywell(s)
Yes No
Yes No
Yes No
Yes No
Page 1 of 2
14 Hydrocad
15 Hydrocad
16
Response Attachment location
17
18 Hydrocad Calculations
≤ 2 in/hr
> 2 in/hr
20*10%
21*Soil Report
2 TRUE
Response Attachment location
22 Plans
23*Plans
24 (ac-ft)0.328 Enter this on the eNOI
25 TV (ac-ft)0.328 Hydrocad Calculations
0
Response Attachment location
26
19*
Has an observation well been installed in every trench, drywell, or subsurface
system?
Treatment Volume (TV) for infiltration practices may be calculated using the equations provided as design guidance
in Section 4.3.3.5 OR by demonstrating infiltration of the TV using TR-20 or an approved equavalent.
Soil Report
What is the treatment volume provided by the STP?
What is the physical storage volume up to the overflow?
Pre-Treatment (4.3.3.3)
Has pretreatment been provided for non-rooftop runoff?
Attachment location: Indicate the specific location (i.e. appendix, page, plan sheet) where the requisite support documentation has
been provided within the application.
Does the site plan specify a landscaping plan that ensures dense and vigorous
vegetation over the contributing pervious drainage areas and the practice?
Landscaping (4.3.2.5)
Treatment (4.3.2.4)
↑ Enter this value on the Standards
Has direct access been provided to the practice for maintenance and
rehabilitation?
Is the forebay separated at least three (3) feet from the SHGWT or located over
impermeable soils?
What type of pretreatment is being
used?
Is the infiltration rate (fc) greater than or less than 2 inches per hour?
Is the forebay sized to hold at least 50% of the WQv?
If the practice is designed to infiltrate <1 year storm and runoff is delivered by
the main conveyance system, has it been designed as an off-line practice?
Have the outfalls and the conveyance to the discharge point been
designed/protected to avoid erosive velocities?
Is the practice designed to completely dewater the treatment volume (TV)
within 48 hours after the storm event?
Swale
Filter Strip
Forebay
Deep Sump Catch Basins
Proprietary
Yes No
Yes No
NoYes
NoYes
Yes No
Yes No
NoYes
Yes No
Yes No
Page 2 of 2
Version: 4/28/2017 Project Name:
Response Attachment location
1
See Grading, Drainage and Erosion Control Plans
2
See Grading, Drainage and Erosion Control Plans
Attachment Location
See Grading, Drainage and Erosion Control Plans
See Grading, Drainage and Erosion Control Plans
See Grading, Drainage and Erosion Control Plans
See Grading, Drainage and Erosion Control Plans
See Grading, Drainage and Erosion Control Plans
Response Attachment location
5 See Grading, Drainage and Erosion Control Plans
BTV Rehabilitate Taxiway A
Does the site layout retain the duff layer and native topsoil in an undisturbed
state to the maximum extent practicable?
4
Feasibility (3.1)
Have all areas that will not be disturbed and areas exempt from the Standard,
including the reason for the exemtion, been identified on a plan sheet?
Have all areas of disturbance within the site that are subject to the Post-
Construction Soil Depth and Quality Standard been identified on a plan sheet?
This includes all disturbed areas on slopes ≤ 33% which are not covered by an
impervious surface, part of a structural stormwater treatment practice, or
engineered as structural fill once development is complete.
Which of the following methods are utilized to meet soil quality requirements for this site?
Post-Construction Soil Depth and Quality Standard
3
Is the minimum topsoil depth specified as:
4 inches
The depth of the 0 and A horizons on the NRCS Official Soil Series Description of
the native mapped soils (provide documentation)
Treatment (3.2)
Option 1: Leave undisturbed native vegetation and soil, and protect from
compaction during construction.
Option 2: Amend existing site topsoil or subsoil in place.
Option 3: Remove and stockpile existing topsoil during grading.
Option 4: Import topsoil mix, or other materials for mixing, including compost, of
sufficient organic content and depth.
Yes No
Yes No
Yes No
Page 1 of 2
6 Minimum 3%
7 N/A
8 N/A
9
N/A
Response Attachment location
10 See Grading, Drainage and Erosion Control Plans
11 See Grading, Drainage and Erosion Control Plans
12
See Grading, Drainage and Erosion Control Plans
13
N/A
14
N/A
15 See Grading, Drainage and Erosion Control Plans
Instructions that test holes shall be excavated using only a shoven driven soley
by the inspector's weight and shall be at least 50 feet apart from each other?
Is the organic matter content of the topsoil layer specified to be at least 4%?
Attachment location: Indicate the specific location (i.e. appendix, page, plan sheet) where the requisite support documentation has been provided within the application.
Includes construction details and notes on the various methods the contractor
may use to meet he Standard?
Instructions to establish dense an vigorous vegeative cover over turf areas?
Is compost or other materials used to amend soils specified to have a C:N ratio
below 25:1?
Is it specified that compost shall meet the definition of "compost" or meet the
contaminant standards in the Vermont Solid Waste Management Rules?
If Exceptional Quality (EQ) biosolids are used as a soil amendment, do they
comprise no more than 35% of the total volume of soil, and is it specifed that
they be well mixed before or during application?
Vegetation and Landscaping (3.3)
Does the application include a site-specific plan for soil management that:
Includes a statement that soil depth and quality shall be established towards
the end of construction, and once established, be protected from compaction?
Identifies all areas on the site subject to the standard?
Includes instructions for contractor verification of the Standard, including a
sampling scheme that includes nine 8-inch deep test holes per acre of area
subject to the Standard?
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
Yes No
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