SW8000529_COMPLIANCE_20000823

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO. SW QC�LS�°I
DOC TYPE ❑ CURRENT PERMIT
❑ APPROVED PLANS
❑ HISTORICAL FILE
COMPLIANCE EVALUATION INSPECTION
DOC DATE,
YYYYMM DD

INFILTRATION BASIN ANALYSIS
DATE',
23-Aug-2000
PROJECT NAME:
Ponds Edge Office Park
DRAINAGE BASIN:
Cape Fear
RECEIVING STREAM:
Pages Creek
Index No.:
18-87-22
SITE AREA 1.48 acres .
IMPERVIOUS AREA CALCULATION
BUILDINGS
PARKING/ASPHALT
CONCRETE
OTHER
% IMPERVIOUS, 1= � 7:3 9N
ELEVATION OF SEASONAL HIGH WATER TABLE
REPORTED INFILTRATION RATE
SURFACE AREAS AND ELEVATIONS
FILENAME: S:1WQS11NBASIN1000529.WK1
PROJECT #: SW8. 000529
REVIEWER: arl
CLASS: SA
If ORW, is site within the 575' AEC?
ET
DRAINAGE AREA: <:>:16563 SF
0.38 acres
Elev. (ft) Area
BOTTOM 32.75 1176 SQUARE FEET
SQUARE FEET
SQUARE FEET
STORAGE 34.25 1728 SQUARE FEET
VOLUME 1 DEPTH 1 DRAWDOWN CALCULATION
DESIGN STORM, INCHES
DESIGN VOLUME
TOTAL VOLUME AVAILABLE
DEPTH OF RUNOFF
5>'
:.3481:CUBIC FEET
CUBIC FEET
1:50 FEET
TIME TO DRAWDOWN 0 3`IDAYS MUST BE <5
COMMENTS
Volume,lfi� it. Drawdown is within Design Requirements.
I

ENGINEERING, INC
2592 Hope Mills Road
Fayetteville, NC 28306
910-426-2323
Tripp Engineering, PC
419 Chestnut Street
Wilmington, North Carolina 28401
QttOnti ry hfir. ('h�rlea 1`aZipr
• V4 MI V V�w♦V�
Reference: Infiltration Evaluation
Ponds Edge Development
Wilmington, North Carolina
Job No.: 3420-00
Dear Mr. Cazier :
xEc;r;ivhL
MAY 1.5 2000
a
PRGJ #
March 20, 2000
Soil Tech Engineering, Inc. has conducted an evaluation of the existing site conditions
at the Ponds Edge development located on highway 17 north of Wilmington, North
Carolina.
We conducted an investigation of the subsurface soils at the designated storm water
infiltration area indicated on the site sketch on March 17, 2000. The purpose of our
investigation was to determine the suitability of the in -place soils for the discharge of
stormwater runoff. We investigated the subsurface soils to a depth of six feet below the
existing ground surface. We also classified each subsurface strata encountered, by
der •'h ptand obtained representative sails samples of each Strata at the designated
location.
Selected soil samples were tested in our laboratory for grain size structure in
accordance with the American Society for Testing and Materials (ASTM) procedures
entitled ASTM D-422; "Particle Size Analysis of Soils". Our sampling indicated that the
subsurface soils at the test location investigated to be a drainable upper strata of fine
grained sands underlain by stratas of black silty sands.

Infiltration Evaluation ,
Ponds Edge Development
Wilmington, North Carolina
Page Two
We also conducted an evaluation of the subsurface infiltration at the designated
location. The infiltration rate of the in -place soils were -determined at a depth of
approximately 24 inches below the existing ground surface at the location investigated.
The infiltration rate was found to be 1.0 inches per minute, based on our analysis.
We encountered saturated subsurface condition at approximately 48 inches below the
existing surface, which should indicate the present groundwater depth. - Our
classification of the subsurface soils indicates that a season high groundwater
condition should be, anti ipa►cu approximately�Q i��3�i icy below the ei�isiin yi viii �v
surface at the test location.
Please find the results of our field and laboratory tests and a sketch indicating our test
locations. Please contact us, if you have questions.
Very truly yours,
SOIL TECH ENGINEERING, INC.
Parks A. Downing, Jr.
Manager
,� ' '' ' ' 1 1 a,�"� '4,0 Fps''• � O �.
r
mes Pate, P. E.
Em�}}�

Infiltration Evaluation
Ponds Edge Development
Wilmington, North Carolina
Job No.: 3418-00
March 17, 2000
Location Depth Soil Deracription
#1 0" - 6" Gray Brown Silty Fine to Medium SAND w/Organics
6" - 42" Light Brown Tan Fine to Medium SAND
42" - 48" Black Silty Fine to Medium SAND
48" - 72" Brown Fine to Medium SAND
Although groundwater was not encountered at depths investigated, the soil was saturated at 48"
below the existing ground surface.
Infiltration Rate : 1.0 inches per minute
Test was conducted at 24 inches below the existing ground surface.

,m
Exi sti ng
Building
A Denotes location of infiltration testing.
Highway 17
�...e
SOI
Infiltration Evaluation
Ponds Edge Development
Wilmington, North Carolina

Grain Size Analysis
Ponds Edge Development
Wilmington, North Carolina
Job No.: 3418-00
Sieve Size
# 10
Percent Passing, By Weight
100.0
# 40
96.5
# 80
7.6
# 200
1.4
Percent Moisture ;
5.8 %
Soil Description :
Light Brown
Tan
Fine to
Medium
SAND

swy coo521? AZ11M /�-/Cep Sf. C�
DIVISION OF WATER QUALITY
INFILTRATION SYSTEM INVESTIGATION
I. The minimum bore depth:
'EX. 5''v0! d 32
P•z�. /-z.An 3 2.75
,� 2
, oy 3
2. The type of soil:
Leon - sad
3. The expected infiltration rate:
60rr/hr
4. The depth to the Seasonal High Water Table:
1�lI v. 2C7
cG� sf� h�Zd fps f"
5. Additional comments:
Q D/Sf0'7(es rn
qlc, orb is ? I'h2s�c� .
5
Signature of Regional Office Personnel:
4�d'c� '176"
Linda Lewis, DWQ
Permit Application No. 6005zq
S :1W QSISTORMWATIFORMSIINFINVST. FOR
Vincent Lewis, Soil Scientist
Date 6' 269`0c-'