HomeMy WebLinkAboutSP-24-08 - Supplemental - 0870 Williston Road (38)Version: 11/30/2020
Treatment Wetlands (4.3.5)
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4
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* Questions preceded by an asterix (*) may change based on previously entered values
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11*
12*
13*
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19*
20*
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30
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
Practice Type
Discharges to Cold or Warm Water Fishery?
Note: Designers may use the Practice Drainage Area Runoff Calculator (second tab) for calculation of practice-specific runoff volumes for other treatment standards.
Conveyance (4.3.5.2)
Are inlets stabilized to ensure that non-erosive conditions exist for at least the 1-year, 24 hour storm?
Has a low for orifice been provided to meet the the WQV and CPV extended detention requirements and designed to ensure no clogging will occur?
Have the outfalls and the conveyance to the discharge point been designed and protected to avoid erosion?
Has a liner designed in accordance with Section 4.3.5.2 been provided if the infiltration rate exceed 0.05 inches per hour and the wetland is located above the average groundwater table?
Have inlet pipes been set at the permanent pool or the base of the gravel bed?
Is outlet elevation designed such that a sub-surface water level is maintained in the gravel wetland?
If the gravel wetland is designed with an organic soil layer at the surface, have vertical perforated riser pipes been provided to deliver stormwater stormwater from the surface down
to the gravel bed?
Pre-Treatment (4.3.6.3)
Has pretreatment been provided for non-rooftop runoff?
What type of pretreatment is being used?
Treatment (4.3.6.4)
What is the volume stored in the forebay or other volumetric pre-treatment if used? (minimum 10% WQV)
What is the volume stored in the permanent pool?
What is the total WQV stored at the normal water level (pre-treatment + permanent pool)?
Does the pre-treatment volume plus the permanent pool equal at least 50% of the WQV?
Is the remaining WQV provided for by extended detention over 24 hours?
Has a minimum flow path at normal water level of 3:1 been provided?
What is the Storage Volume of the practice. Include the permanent pool and any volume used for providing extended detention.
Landscaping (4.3.6.5)
Are all deep pool areas of ≥ 4 feet depth with side slopes steeper than 4:1 (H:V) surrounded by a safety bench with ≤6% slope extending 10 feet outward from the normal water edge to
the toe of the side slope?
Has an aquatic been been provided that extends at least 5 feet inward from the normal water edge and is no more than 18 inches deep?
Has a planting plan been prepared showing how aquatic and terrestrial areas will be stabilized, including plant species, plant locations, sources of plant material and any required soil
amendments?
Has a setback been provided that extends 25 feet from the maximum design water surface elevation of the practice?
Does the planting plan specify that no woody vegetation >2 inches in diameter shall be planted or allowed to grow on the dam, within 15 feet of the dam or the toe of the embankment,
or within 25 of a principal spillway outlet?
Are any donor organic soils used in the practice obtained from a source other than natural wetlands?
Total Area (acres)
WQV to practice
For Permit Coverage
0.937899311294766
0.305781965105602
0.190564993112948
WQV for credit
3.59417053202479E-02
↑Enter this value on the Standards Compliance Workbook
Not for Permit Coverage
0
0
0
WQV not for credit
0
2
Total to Practice
0.937899311294766
0.305781965105602
0.190564993112948
Total WQV
3.59417053202479E-02
2
Project Name:
Discharge Point:
Treatment Wetland #
Modified CN for WQ (1.0") storm
ft3
ft3
ft3
ac-ft
DoubleTree & Catamount Woods
1
2
Response
Response
Response
0
832
832
0.531418630729367
0.07
Response
93.1856153926316
Attachment location
No direct pipe inlets
Modeling
Plans
Plans
N/A
Plans
Plans
Attachment location
Plans
Attachment location
N/A
Modeling
Modeling
Yes
Modeling
Plans
Enter this on the eNOI
Attachment location
No deep pools
N/A
Plans
N/A
Plans
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
8.59107324494228E-02
0.174327075162664
0.287347080806156
Average Catchment Slope, Y (%)
0
0.08
0
1 yr, 24 hr
1.87
B
0
0
0
0
0
B
0
0
0
0
0
ac-ft
Post Development Runoff Volume
8.59107324494228E-02
0.174327075162664
0.287347080806156
Hydraulic Length, l (ft)
0
216
0
10 yr, 24 hr
3.2
C
0
0
0
0
0
C
0
0
0
3.90632300275482E-02
3.90632300275482E-02
Pre-development Runoff Volume
0
0
0
Time of Concentration, TC (min)
1 yr
0
2.15445301822889
0
Project Name:
Discharge Point:
Treatment Wetland #
NOAA Atlas 14
100 yr, 24 hr
4.78
D
0
0
0
0
0
D
0.441552353076217
0
0
0.457283728191001
0.898836081267218
TV credit of this practice:
Post Composite CN (to practice)
91.6933528935381
90.6928246337433
90.11608510853
10 yr
0
2.24877817832301
0
DoubleTree & Catamount Woods
1
2
Total (acres)
0
0
0
0
0
Total (acres)
0.441552353076217
0
0
0.496346958218549
0.937899311294766
0
CNAdj (with TV practice credit)
91.6933528935381
90.6928246337433
90.11608510853
100 yr
0
2.30331869891078
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