Conservation Commission Regular Meeting Materials (linked)

ADDENDUM
TO DRAINAGE REPORT
FOR
SELF STORAGE
934 & 940 HARTFORD TURNPIKE
WATERFORD, CT
TR-55 MODEL
There will be one on-site drainage area for the proposed development area. Please
see the attached plans entitled Drainage Area Map. There is no off-site drainage flow to
the development area
For the existing conditions where the project is proposed, the area presently
consists of disturbed woodlands, in poor conditions and the old road bed for Route 85.
Due to the fact that the area has been previously disturbed with some steep to moderate
slopes, we used a CN value of 66, soil type B.
Once the construction is complete, there will be 1.3 acres of impervious surfaces
(roofs and pavement). Using a coefficient of CN = 98 for the impervious surfaces and CN
= 66 for lawns/woodlands, poor conditions, soil type B, the overall CN for the drainage
area was calculated to be 85.
Both the existing and the proposed conditions for the development site have been
analyzed for the 2-year, 10-year, 25-year, and 100-year design storms. The rational
method is used for the sizing of catch basin pipes. In this addendum, the TR-55 method
was used to model the basins and outfalls. The following are the summary tables for the
2-year, 10-year, 25-year, and 100-year design storms showing first the existing
conditions, then the proposed conditions for the drainage area after passing thru the
proposed Water Quality Basins. The calculations show that there will be an overall
decrease in runoff leaving the site. The following are the results of the TR-55 computer
model.

Drainage Area
2-year 10-year 25-year 100-year
Existing 1.117 cfs 3.066 cfs 4.481 cfs 6.839 cfs
Proposed 0.000 cfs 0.000 cfs 0.590 cfs 5.159 cfs
Test holes and permeability rates were calculated for the forebay and the stormwater
basin. These rates were divided by 2 as a safety factor and used to include infiltration in
the TR-55 models.
The results of the TR-55 show that there will be no outflow from the basins in up to and
including the 10 year design storm event. In the 25 year storm, there will be a peak flow
of 0.59 cfs leaving the stormwater basin. And in the 100 year storm event there will be a
peak flow of 5.2 cfs leaving the basins thru a 20 foot wide riprap level spreader. There is
no potential for erosion even during the 100 year storm event. There is over 1 foot of
freeboard provided in the basins during the 100 year storm event.

Hydrograph Summary Reportlow Hydrographs Extension for AutoCAD® Civil 3D® 2009 by Autodesk, Inc. v6.066
Hyd.| Hydrograph Peak Time | Time to Hyd. Inflow Maximum Total Hydrograph
No. type. flow |interval| peak volume hyd(s) elevation strge used description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 1.117 1 733 5,267 Se ne Existing Conditions
2 SCS Runoff 3.603 1 729 13,543 | www ee cooeee Proposed Conditions
3 Reservoir 0.494 1 767 3,368 2 102.06 7,261 Forebay
4 Reservoir 0.000 1 844 0 3 99.56 1,461 Basin 1 Discharge
Self Storage TR55.gpw Return Period: 2 Year Friday, May 13, 2022

Hydrograph Summary Reportiow Hydrographs Extension for AutoCAD® Civil 3D® 2009 by Autodesk, Inc. v6.066
3
Hyd.) Hydrograph Peak Time | Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval] peak volume hyd(s) elevation strge used description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 3.066 1 731 12,642 Sa Cr Existing Conditions
2 SCS Runoff 6.374 1 729 24,202 wf wee ------ Proposed Conditions
3 Reservoir 5.203 1 734 13,585 2 102.34 8,321 Forebay
4 Reservoir 0.000 1 735 0 3 101.32 7,343 Basin 1 Discharge
Self Storage TR55.gpw Return Period: 10 Year Friday, May 13, 2022

4
Hydrograph Summary Report
ratlow Hydrographs Extension for AutoCAD® Civil 3D® 2009 by Autodesk, Inc. v6.066
Hyd.| Hydrograph Peak Time | Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval] peak volume hyd(s) elevation strge used description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 4.481 1 731 18,039 Sea OC Existing Conditions
2 SCS Runoff 8.129 1 729 31,153 | wee pf ane Proposed Conditions
3 Reservoir 7.608 1 731 20,355 2 102.44 8,695 Forebay
4 Reservoir 0.590 1 776 1,835 3 102.06 10,531 Basin 1 Discharge
Self Storage TR55.gpw Return Period: 25 Year Friday, May 13, 2022

Hydrograph Summary Report
ratlow Hydrographs Extension for AutoCAD® Civil 3D® 2009 by Autodesk, Inc. v6.066
5
Hyd.} Hydrograph Peak Time | Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval| peak volume hyd(s) elevation strge used description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 6.839 1 730 27,144 | ------ Sn Existing Conditions
2 SCS Runoff 10.84 1 729 42,131 | mre fe ee Proposed Conditions
3 Reservoir 10.37 1 731 31,077 2 102.54 9,078 Forebay
4 Reservoir 5.159 1 744 10,312 3 102.29 11,873 Basin 1 Discharge
Return Period: 100 Year Friday, May 13, 2022
Self Storage TR55.gpw

Civil ¢ Structural ¢ Survey PROVECT Ne:
- 317 Main Street ay. DATE
( NORWICH, CONNECTICUT 06360 :
860-886-1966 SCALE:
FAX 860-886-9165
SHEET NO. OF
Xie Ct Gl (120005, Poot COND! Toe, Soe ripen),
OroPoeeD Ch! _ T ECE] =k
a i a | |
Lie Ae pe Re ere ah, “EERE
0.7 ACeEES KX @/ = AA? |
172.|.
Zine
Crest age pee ee FHA
_| _| |
: 7 OCC CCC eee
Tet Opevoresen: : SEECECEEEEEEEHH
G. Ayer (e soot it = o,n0 Hes = 12 Mit fo Heo
PYZMELBIUTIES
foeqeey- THY? ~ 3.36 erly = 1,7. valve /2- aan
STORM WA e Pop THe] = 4,12 erloay = 2.06. lita oer ioc 1
= [| —t
coffe Cae oe SHEER EE EEE
SU ALO CONCERTED Flow ~ aisha} =H HE | HHH E-EH
BELUXE FOR BUSINESS 1-800-888-6327 . : Ref.No:G 315708550

CLA Engineers, Inc.
Civil * Structural * Survey
317 MAIN STREET e NORWICH, CT 06360 ° (860) 886-1966 e (860) 886-9165 FAX
Permeability of Soils using Compaction Permeameter
Date: 4/1/2022
Project: Dunn Self Storage
CLA Project #: 7045
Material: On-site material (Test Pits)
Specification: Compacted to 94.0 lbs/cu ft per Soil Profiles
See attached test log for reference
Sample #1: Test Pit #1
Permeability: 1.45 x 10-3 cm/sec or 4.12 ft/day
Sample #2: Test Pit #2
Permeability: 1.19 x 10-3 cm/sec or 3.38 ft/day
Sample #3: Test Pit #3
Permeability: 1.34 x 10-3 cm/sec or 3.81 ft/day
Sample #4: Test Pit #4
Permeability: 8. 0-4 cm/sec or 2.32 ft/day
Thoihds Cummfhings 4272
PE No. 9606

CLA Engineers, Inc.
Civil © Structural * Survey
317 MAIN STREET ° NORWICH, CT 06360 e (860) 886-1966 ° (860) 886-91.65 FAX
SIEVE ANALYSIS
Date: 3/25/2022
Project: Dunn Self Storage
CLA Project #: 7045
Material: On-site material (Test Pits)
Specification: N/A
Sample Designation: TH #1
Sieve Size % Passing
3/4 in 87.3
¥%, in 82.7
HA 78.2
#10 70.1
#20 54.9
#40 . 34.6
#60 16.9
#100 6.7
#200 1.6
Thomas-Cummings phd een
PE No. 9606

SIEVE ANALYSIS
CLIENT:
Dunn Self Storage DATE: 3/25/2022
PROJECT: Dunn Self Storage BY: JB
SOURCE: Test Pits SAMPLE: TPH
SAMPLING METHOD Sampled On-site SPEC: NIA
Gross Sieve Net % %
Sieve Weight Weight Weight Retained Pass Spec
3/4 in 149 12.7 87.3
1/4 in 202.7 17.3 82.7
#4 254.8 21.8 78.2
#10 349.8 29.9 70.1
#20 527 45.1 54.9
#40 764.8 65.4 34.6
#60 972 83.1 16.9
#100 1091 93.3 6.7
#200 1150.6 98.4 1.6
1169.6
M:\7000\7000\7045 Dunn Self Storage - Waterford\Material Testing\7045 - TP #1 - 2-25 -22.xs

TEST PIT DATA
EXCAVATED NOVEMBER 11, 2016
BY DICESARE-BENTLEY ENGINEERS
TESTHOLE1 TOTAL DEPTH: 108”
0”-8” TOPSOIL
8”-26” BROWN SILTY FINE SAND
26"-54” COMPACT BROWN SILTY FINE, MOTTLED THROUGHOUT
54”- 108” GREY FINE TO COARSE SAND, TRACE GRAVEL
MOTTILING @ 26”, WATER @ 54”, NO LEDGE
TEST HOLE 2 TOTAL DEPTH: 72”
0”-12” TOPSOIL
12”-32” BROWN SILTY FINE SAND
32"-72” COMPACT GREY FINE-COARSE SAND, TRACE GRAVEL
MOTTILING @ 32”, NO WATER, LEDGE @ 72”
TESTHOLE3 TOTAL DEPTH: 84”
0”-8” TOPSOIL
8”-36” BROWN SILTY FINE SAND
36"-72” MOIST, MODERATELY COMPACT GREY FINE-COARSE SAND, TRACE GRAVEL
48”-84” GREY COARSE SAND WITH RED LENSES
NO MOTTILING, WATER @ 78”, NO LEDGE
TEST HOLE 4 TOTAL DEPTH: 144”
0”-12” TOPSOIL
12”-36” BROWN SILTY FINE-MEDIUM SAND
36"-144” MOIST, MODERATELY COMPACT GREY FINE-COARSE SAND, TRACE GRAVEL
NO WATER, LEDGE @ 144”

MOISTURE DENSITY
(4" Mold)
CLIENT: Dunn Self Storage DATE: 3/30 & 3/34/2022
PROJECT: Dunn Self Storage BY: JB
SAMPLE: Test Pits #1, 2,3, & 4 SOURCE: TP
SAMPLING METHOD: Sampled On-site SPEC: Compacted to 94.0 Ib/cu ft
SAMPLE FA Sample + Pan - Pan Weight + Sample
wet / - = 0.200
dry/ : = 0.176 M/C 13.64
wet / - dry/ = 0.024 Idry 13.6 =M/C
Net Weight 6.950
§.728 4.126 = 1.602 10.033 = 48.55 *2.2= 106.80 M.M/C= 94.0
Full Mold Weight - Mold = Net Weight
—— Sample + Pan - Pan Weight + Sample
wet / - = 0.200
'dry/ - = 0.173 M/C 15.61
wet / - dry/ = 0.027 Idry 15.6 =M/C
Net Weight 6.950
5.756 | -4.126 = | 1.630 10.033 = 49.39 *2.2= 108.67 M.M/C= 94.0
Full Mold Weight - Mold = Net Weight
— Sample + Pan - Pan Weight + Sample
wet / - = 0.200
dry / : = 0.188 M/C 6.38
wet / - dry/ = 0.012 Idry 6.4 =M/C
Net Weight 6.950
5.626 4.126 = 1.500 10.033 = 45.45 *2.2= 100.00 M1.M/C= 94.0
Full Mold Weight - Mold = Net Weight
— Sample + Pan - Pan Weight + Sample
wet / - = 0.200
dry/ : = 0.158 M/C 26.58
wet / - dry/ = 0.042 Idry 26.6 =M/C
Net Weight 6.950
5.911 ~4.126 = 1.785 10.033 = 54.09 *2.2= | 119.00 M.M/C= 94.0
Full Mold Weight - Mold = Net Weight
Sample + Pan - Pan Weight + Sample
wet / - = 0.200
dry/ - = M/C #DIVIO!
wet / - dry/ = 0.200 ldry #DIVIO! =M/C
Net Weight 6.950
4.126 = 4.126 10.033 = 125.03 | *2.2= | -275.07 M.MIC= #DIVIO!
Full Mold Weight - Mold = Net Weight
C:\Users\jbrown\Desktop\Worksheets\MoistureDensity-4Mold.xis

PUM SELF STORAGE 3)0, 3a. # A): [oce:
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= oe (453 % ZF3B4.4L v= Hi2 Chlday
tH # 2 - Bhouwn Siety Sand O/ FEW STONES
kK =O0If2 y DY 34. we K-= 7.318 €t/de,
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IK. = ee Fiesc ~~ ATER k= (Beh 497
v= .0034\ ¥ 2934.GU & K- 2B Ht [aay
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Y= da RL 30 E> 2OZ¥ 7G f= Y.F3 Kd ¢
L= 000893 ¥ 2934. LHL K= 2.32 Ct (day

CLA Engineers, Inc.
Civil * Structural * Survey
317 MAIN STREET )
NORWICH, CT 06360
e (860) 886-1966
SIEVE ANALYSIS
Date: 3/25/2022
Project: Dunn Self Storage
CLA Project #: 7045
Material: On-site material (Test Pits)
Specification: N/A
Sample Designation: TH #2
Sieve Size
% Passing
Thomas Cummings ,4y222_
PE No. 9606
94.7
82.0
80.5
63.5
49.3
47.5
36.0
24.8
13.6
° (860) 886-9165 FAX

SIEVE ANALYSIS
CLIENT: Dunn Self Storage DATE: 3/25/2022
PROJECT: Dunn Self Storage BY: JB
SOURCE: Test Pits SAMPLE: TP #2
SAMPLING METHOD Sampled On-site SPEC: NIA
Gross Sieve Net % %
Sieve Weight Weight Weight Retained Pass Spec
3/4 in 40.6 5.3 94.7
1/4 in 137.6 18.0 82.0
#4 149.4 19.5 80.5
#10 279.4 36.5 63.5
#20 387.6 50.7 49.3
#40 401.2 52.5 47.5
#60 489.6 64.0 36.0
#100 574.8 75.2 24.8
#200 660.6 86.4 13.6
764.6
M:\7000\7000\7045 Dunn Self Storage - Waterford\Material Testing\7045 - TP #3 - 2-25 -22.x's