INFILITRATION TESTING REPORT

FOR

3110 MONROE STREET NE

WASHINGTON, DC 20018

PREPARED FOR

ARCHI-TEXTUAL, PLLC

WASHINGTON, DC

PREPARED BY: BEL-ENGINEERING, LLC

4542 BEECH RD

TEMPLE HILLS, MD

PROJECT NO.: 2019-029

Board of Zoning AdjustmentDistrict of ColumbiaCASE NO.19914EXHIBIT NO.67

WWW.BEL-ENGINEERING.COM 4542 BEECH RD. TEMPLE HILLS, MD 20748 240.830.2555

February 19, 2019 Catarina Ferreira, AIA, NCARB Principal at ARCHI-TEXTUAL PLLC 3421 ½ M St NW, STE. A, Washington, DC 20007 cferreira@architextual.com Reference: Infiltration Testing Report 3110 Monroe St NE Washington, DC 20018 Dear Ms. Ferreira: Pursuant to your request, and per our agreement, BEL Engineering, LLC (BEL) is pleased to present this letter that summarizes our findings of in-situ infiltration testing carried out at one selected location at the proposed development at 3110 Monroe St NE in Washington, DC. The soils percolation/infiltration was carried out at the selected location identified as “I-1” as shown on the attached Boring Location Plan. The purpose of the testing is to provide permeability/infiltration rate estimates of the shallow soils at the site for stormwater facility.

Permeability Test Method and Field Procedures

BEL Engineering used the Johnson Permeameters to perform a constant head infiltration test which is in general accordance with the publication entitled” DDOE (District Department of the Environment) Stormwater Guidebook, Appendix O.”

The hole is prepared in general accordance with the information contained in the Johnson Permeameter TM Instruction Manual dated May 17, 2018. A schematic of the equipment used included in the Appendix of this report for reference. The test is then performed in general accordance with the same manual and the test results are recorded during testing of each locations. The final design rate chosen is ultimately the discretion of the design engineer; however, is typically the last three to four readings taken during the test or the last reading, as appropriate, based on the test results. The result of each infiltration test is included in the Appendix of this report for reference.

In-Situ Infiltration Test Results

The infiltration rates contained in this report are based on one infiltration boring performed at the project site to a depth of about 6 feet below existing ground surface. Based on the in-situ infiltration testing conducted in accordance to the procedures depicted above, the soils’ infiltration rates at the test locations are as follows (see also the test data in the appendix of this report):

Infiltration Test No. Approximate Test Depth (feet) Estimated Infiltration Rate

(inches/hour)

I-1 6.0 0.26 in/hrs

Laboratory Testing

In addition to the in-situ tests, a laboratory classification test was performed. The laboratory testing was performed on the hand auger sample obtained from about 6 feet below the test boring HA-1. Testing includes USDA and USCS soil classification, and moisture content.

The classification test method is performed with grain-size sieve analyses including hydrometer testing on samples obtained from corresponding proposed infiltration depths, to determine both USCS and the USDA soil texture classifications. Based on the USCS classification the soils sampled classified as Clayey Sand (SC). Based on the USDA soil texture classification, the soil sampled was obtained to be Sandy Clay Loam. Published correlations between USDA classifications and infiltration rates were used to provide estimated hydraulic conductivity values. Since hydraulic conductivity and infiltration values are essentially equal at no head conditions, using the hydraulic conductivity values to estimate the infiltration rates provides a conservative estimate of infiltration for use in design. In this case, the classified soil (i.e. Sandy Clay Loam) and has an infiltration rate of 0.2 inches per hour.

Groundwater Conditions

Observations for perched groundwater or shallow water table conditions were performed in the hand auger (HA-1), and no water was encountered up to 10’-0” feet below the ground level. Hence, it meets the minimum requirement for the separation depth of the ground water table from the bottom of the infiltration facility.

Bedrock Conditions

Bedrock is defined as materials exhibiting a minimum SPT N-value of 60 bpf. Based on the geotechnical investigation performed and site geology, and bedrock is not encountered to affect the proposed infiltration facility.

Qualification

In providing this exploration and professional recommendations our services were performed in accordance with generally accepted engineering principles and practices. No warranty, either expressed or implied, is made to the professional advice included in this report. This report has been prepared for the exclusive use of the Client to assist them and their engineers during the design and construction phases of the proposed development. The opinions, conclusions, and recommendations contained herein are based upon the field work performed, our interpretation of the data, and generally accepted principles of geotechnical engineering. Please be advised that although the test borings were logged by experienced engineers, it is sometimes difficult to record changes in subsoil stratigraphy within narrow limits; therefore, some deviation in the materials reported on the field logs and the materials encountered in the field should be anticipated. Any change in soil type observed during construction or change in proposed location of the structure or grades should be provided to us so that we may modify portions of this text if necessary. Any conclusions or recommendations that are based on data contained in this report that are made by others are the responsibility of others. This letter report does not address any environmental wetlands, forestry, erosion control, cost estimates, facility design issues or impact, if any, on the project.

We thank you for your confidence in our services. We will remain available for future consultation during the design and construction phases of the project.

Should you have any questions regarding the content of this report, please do not hesitate to call us at (240) 830-2555

Respectfully,

BEL ENGINEERING, LLC

Wondwosen B. Ali, P.E., PhD. Principal Engineer

Approximate Boring Location Plan

0

1.5

3

4.5

6

7.5

9

10.5

HA1

7-8-10(DCP)

LL=36PL-18PI=18

FILL

SC

SC

2.0

10.0

Brown Silty Sand with gravel and organic material, moist

Reddish Brown Clayey Sand (SC), loose to medium dense

Auger termination

BORING NUMBER HA-1

CLIENT ARCHI-TEXTUAL PLLC PROJECT NAME 3110 Monroe St NE

PROJECT NUMBER 2019-029 PROJECT LOCATION 3110 Monroe St NE, Washington DC

DATE STARTED 02-04-2019 COMPLETED 02-04-2019 GROUND ELEVATION HOLE SIZE 3.25

DRILLING CONTRACTOR BEL Engineering LLC GROUNDWATER LEVELS

DRILLING METHOD Hand Auger AT TIME OF DRILLING none

LOGGED BY M.A. CHECKED BY W.A. AT END OF DRILLING none

BORING LOCATION SEE BORING LOCATION PLAN 24hrs AFTER DRILLING none

DE

PT

H

(ft.

)

SA

MP

LE

TY

PE

NU

MB

ER

RE

CO

VE

RY

%

BLO

W

CO

UN

TS

(NV

ALU

E)

TESTS

U.S

.C.S

.

GR

AP

HIC

LO

G

MATERIAL DESCRIPTION

PAGE 1 OF 1

Tested By: MA Checked By: WA

LL PL D85 D60 D50 D30 D15 D10 Cc Cu

Material Description USCS AASHTO

Project No. Client: Remarks:

Project:

Source of Sample: HA-1 Depth: 6 Sample Number: 1

Figure

36 18 6.8210 0.3937 0.1115 0.0424

Reddish Brown Clayey Sand SC A-6(4)

2019-029 ARCHI-TEXTUAL PLLC

PE

RC

EN

T F

INE

R

0

10

20

30

40

50

60

70

80

90

100

GRAIN SIZE - mm.

0.0010.010.1110100

% Stones % +3"Coarse Medium

% Gravel

Fine V. Crs. Crs. Med. Fine

% Sand

V. Fine Crs.

% Silt

Fine% Clay

0.0 0.0 0.0 21.4 2.7 3.8 8.7 8.9 5.5 14.7 10.5 5.1 18.7

6 in

.

3 in

.

2 in

.

1½

in

.

1 in

.

¾ in

.

½ in

.

3/8

in

.

#4

#1

0

#2

0

#3

0

#4

0

#6

0

#1

00

#1

40

#2

00

Particle Size Distribution Report

3110 Monroe St NE

USDA Soil Classification

siltloam

sand

siltyclay loam

loam

clay loam

sandy loam

siltyclay

sandyclay loam

loamy sand

clay

silt

sandyclay

0 100

0

10 90

10

20 80

20

30 70

30

40 60

40

50 50

50

60 40

60

70 30

70

80 20

80

90 10

90

100 0

100

Percent Sand

Perc

ent C

lay

Perc

ent S

ilt

SOIL DATA

SourceSample Depth

ClassificationNo.

Percentages From Material Passing a #10 Sieve

Sand Silt Clay

Client:

Project:

Project No.: Figure

ARCHI-TEXTUAL PLLC

3110 Monroe St NE

2019-029

HA-1 1 6 52.7 22.7 24.6 Sandy clay loam

File Name…..:

Project Name………....: Boring No…….....:

Project No……...........: Investigators…...:

Project Location……...: Date….………......:

Boring Depth………....: 182 cm (Specify units) WCU Base Ht. h: 10.0 cm*** 20

Boring Diameter…....: 9.38 cm WCU Susp. Ht. S: 20.0 cm

Boring Radius r……...: 4.69 cm Const. Wtr. Ht. H: 30.0 cm

Soil Temperature T..: 10 °C H/r**……......……: 6.4

Dyn. Visc. @ T……....: 0.001308 kg/m·s Dyn. Visc. @ TB.: 0.001003 kg/m·s

Reservoir Volume Time (12 hr) Volume Out Flow Rate(ml) (h:mm:ss A/P) (ml) Total (min) Interval (min) (ml/min) (µm/sec) (cm/sec) (cm/day) (in/hr) (ft/day)

3,200 2:10:00 PM

2,910 2:12:00 PM 290 2.00 2.00 145.0 9.5 9.47E-04 81.8 1.34 2.69

2,660 2:17:00 PM 250 7.00 5.00 50.0 3.3 3.27E-04 28.2 0.46 0.93

2,510 2:22:00 PM 150 12.00 5.00 30.0 2.0 1.96E-04 16.9 0.28 0.56

2,360 2:27:00 PM 150 17.00 5.00 30.0 2.0 1.96E-04 16.9 0.28 0.56

2,210 2:32:00 PM 150 22.00 5.00 30.0 2.0 1.96E-04 16.9 0.28 0.56

2,060 2:37:00 PM 150 27.00 5.00 30.0 2.0 1.96E-04 16.9 0.28 0.56

1,920 2:42:00 PM 140 32.00 5.00 28.0 1.8 1.83E-04 15.8 0.26 0.52

1,780 2:47:00 PM 140 37.00 5.00 28.0 1.8 1.83E-04 15.8 0.26 0.52

1,640 2:52:00 PM 140 42.00 5.00 28.0 1.8 1.83E-04 15.8 0.26 0.52

Natural Moisture……..: 16.9% Consistence…...: 0.26 in/Hr

USDA Txt./USCS Class: Sandy Clay Loam WT Depth……....: > 10' Data Logger No….: 1

Struct./% Pass. #200..: Init. Sat. Time...:

Solution: USBR 7300-89 Condition I (Deep WT or Impermeable layer)

*USBR 7300-89 Condition I exists when the distance from the water surface in the borehole to the water table or an impermiable layer is ≥3X the depth of the water in the borehole. **H/r ≥5 - ≤10. ***Model JP-M1: h = 15 cm,

WCU-3 (3"): h = 10 cm, WCU-2 (2") h = 17 cm. © Johnson Permeameter, LLC. Revised 05/17/2018

EXAMPLE 6b

--------------------- KB Equivalent Values --------------------------

3110 Monroe St NE

2019-029

3110 Monroe St NE, Washington, DC

Solution and Terminology (USBR 7300-89 Condition I)*

where:

Q: Rate of flow of water from the borehole

H: Constant height of water in the borehole

r: Radius of the cylindrical borehole

V: Dynamic viscosity of water @ T °C/Dyn. Visc. of water @ TB °C

KB: Coefficient of Permeability @ base Tmp. TB °C:

Constant-Head Borehole Permeameter Test

Enter Average KB Value…...…...:

I-1

Note: KB is determined by visually analyzing the Flow Rate vs Elapsed Time Graph and

averaging the the results for the final three to five stabilized values.

BEL ENGINEERING

02/04/2019

Elapsed Time

KB = QV/(2πH2)[ln{H/r+((H/r)2+1)0.5}-((H/r)2+1)0.5/(H/r)+1/(H/r))]

0

20

40

60

80

100

120

140

160

0 5 10 15 20 25 30 35 40 45

Flo

w R

ate

(m

l/m

in)

Elapsed Time (min)

Flow Rate vs Elapsed Time

Pictures During Field Infiltration Testing