20100647 Ver 1_Stormwater Info_20110112

DUNCKLEE ENVIRONMENTAL CONSULTING & ENGINEERING
511 KEISLER DRIVE - SUITE 102
& DUNHAM GARY, NORTH CAROLINA 27518
OFFICE: [phone]
WWW DUNCKLEEDUNHAM.COM
LETTER OF TRANSMITTAL
lo- oto4'7
To: Amy Chapman k[A@[90W§ D
From: Andrew Rodak JAN 1 2 2011
UEHt•01BOOM
WET MAt1D STOW ATSBRANCH
Date: 1/12/11
RE: Stormwater management Plan, DWQ Project No. 2010-0647
The following document is attached:
( ) Draft Letter / Report (X) Final Letter / Report
( ) Laboratory Report
( ) Contract or Change Order
For the following action:
Certification Forms
Other:
( X ) For Your Review / Information
( ) As You Requested
( ) For Your Signature & Return
( ) Other
Comments:
Amy:
Attached is the Stormwater Management plan for 104 Aberson Court, Cary NC (UT to Crabtree Creek
030402, 27-33-(10)) in support of a Minor Variance Authorization issued by the DWQ on 9/23/10.
Please provide Annette Lucas with a copy.
Po",I OFFIC! Bf }t_iS Noll III (' \Iw1 1""_11/O.-(y
(3t?:aRi)OI I si/?1 I ?:S I h ..VS ( ;7?`)
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t h ki[C?iti l i kl u I ...! 31.1, 00061
i
DUNCKLEE
& DUNHAM
January 11, 2011
ENVIRONMENTAL CONSULTING & ENGINEERING
511 KEISLER DRIVE - SUITE 102
CARY, NORTH CAROLINA 27518
OFFICE: [phone]
W W W.DUNCKLEEDUNHAM.COM
10 - D (p +,7
Ms. Annette Lucas, P.E.
North Carolina Department of Environment and Natural Resources
Division of Water Quality
401 Oversight and Express Permitting Unit
512 North Salisbury Street
1650 Mail Service Center
Raleigh, North Carolina 27604
Reference: Variance Request Support- Stormwater Management Plan
104 Aberson Court
Cary, Wake County, North Carolina
Dear Ms. Lucas:
JAN 12 2011
MEIIa
?bsaxosmv?q
On behalf of our client Arthur Begun, Duncklee & Dunham, P.C. (Duncklee & Dunham) is pleased to
present the attached stormwater management plan for construction of a Best Management Practice (BMP)
for the above-referenced property. The purpose of the BMP is to capture and treat post-construction
stormwater runoff associated with construction of a sunroom addition on the property, pursuant to the
provisions of an Authorization of Neuse River Riparian Buffer Protection Rules Minor Variance (Minor
Variance) granted by the North Carolina Division of Water Quality (NC DWQ) on September 23, 2010.
The Variance allows for the buffer impact of approximately 242 square feet within
Zone 2 of the Neuse River Watershed Riparian Buffer that traverses the property for the purpose of
constructing a sunroom addition to the existing residential structure on the property. A provision of the
Variance requires the design and construction of a stormwater BMP device to capture post-construction
stormwater runoff from impervious surfaces on the property and control nutrient and sediment impacts
associated with these impervious surfaces that would impact the Riparian Buffer.
The proposed stormwater BMP device for this property is a bioretention area ("rain garden") that will
collect and treat post-construction runoff from the roof of the sunroom addition as well as a portion of
roof runoff from the existing structure. The design of this BMP device is submitted as part of a
Stormwater Management Plan for the site that must be approved by the NC DWQ before construction of
the BMP can begin.
MAILING ADDRESS - POS['01 FICF BOX 33366 - RALEIGH, NORTH CAROLINA 27636
NOR'I II CAROLINA BOARD OF EXAMINFRS FOR ENGINEERS AND SURVEYORS 1.10 NSE C-3559
NOR IH CAROLINA BOARD FOR LICENSING OF GEOLOGISTS LICENSE C-261
NC DENR REGISTERED ENVIRONMENTAL CON'Slfl_IAN I NUMBER 00061
rat ",
Stormwater Management Plan
104 Aberson Court
Cary, North Carolina
January 11, 2011
Page 2 of 2
Attached to this letter are one original and two copies of the following:
• The Site Plan (Figure 1) depicting the existing residential structure and proposed addition, Riparian
Buffer zones, project boundary, original and proposed contours, delineated potential zone buffer
impact area, existing on-site drainage, and location of the proposed BMP;
• Locations and details for proposed structural BMP (Figures 2-4);
• The applicable BMP Supplement and I&M Forms for the proposed BMP;
• Supporting design calculations for the BMP
If you have any questions, or require any additional information, please call us at [phone] or via
email at andygdunckleedunham.com.
Sincerely,
Duncklee & Dunham, P.C.

Andrew M. Rodak, P.E.
Senior Engineer
Senior Peer Review:
Bryson D. Trexler, Jr., Ph.D., L.G.
Senior Hydrogeologist
Attachments
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P:\Begun Property\Correspondence\SW Management Plan- 11014.doc

DUNCKLEE & DUNHAM, P.C.
Permit Number:
(to be provided by DWQ)
?? ware
t
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
BIORETENTION CELL SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part Ill) must be printed, filled out and submitted along with all of the required information.
f. PROEM WOM701
Project name 104 Abebson Court
Contact name Andrew Rodak
Phone number [phone]
Date January 3, 2011
Drainage area number A
IL
Site Characteristics
Drainage area 1,200 ft2
Impervious area 6550 ft2
Percent impervious 54.2% %
Design rainfall depth 1.6 inch
Peak Flow Calculations
Is preipost control of the 1-yr, 24-hr peak flow required?
1-yr, 24-hr runoff depth
1-yr, 24-hr intensity
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak control
Storage Volume: Non-SA Waters
Minimum volume required
Volume provided
Storage Volume: SA Waters
1.5' runoff volume
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Cell Dimensions
Ponding depth of water
Pending depth of water
Surface area of the top of the bioretention cell
Length:
Width.
-or- Radius
Media and Soils Swam ry
Drawdown time, ponded volume
Drawdown time, to 24 inches below surface
Drawdown time. total:
In-situ soil:
Soil permeability
Ptanting media soil:
Soil permeability
Sal composition
• Sand (by weiytt)
• Fines (by weight)
% Organic (by weight)
Phosphorus Index (P-Index) of media
Form SW401-eioretp vbon-Rev.a
July 30, 2009
N (Y or N)
1.6 in
0.12 in/hr
0.001 ft3/sec
0.003 ft3/sec
0.002 ft3/SeC
87A ft3
158.7 ft3 OK
ft3
'ft3
_ ft3
0 ft3
ft3
9 inches OK
0.75 It
119.0 #2 OK
11 ft OK
lift OK
it
9 hr OK
24 hr OK
33 hr
021 inittr Insufficient. Increase Ofiltration rate.
1.00 m r OK
85% OK
1 OK
5% OK
Total: 1006
20 (unitless) OK
Parts I and It. Desgn Summary, Page 1 of 2
Permit Number:
(to be provided by DWQ)
Basin Elevations
Temporary pool elevation 356.25 fmsl
Type of bioretention cell (answer "Y" to only one of the two
following questions):
Is this a grassed cell? Y (Y or N) OK
Is this a cell with trees/shrubs? N _(Y or N)
Planting elevation (top of the mulch or grass sod layer) 355.5 fmsl
Depth of mulch 2 inches OK
Bottom of the planting media soil 353.5 fmsl
Planting media depth 2 ft
Depth of washed sand below planting media soil 0.33 ft
Are underdrains being installed? Y (Y or N)
How many clean out pipes are being installed? 1 OK
What factor of safety is used for sizing the underdrains? (See 10 OK
BMP Manual Section 12.3.6)
Additional distance between the bottom of the planting media and 1 ft
the bottom of the cell to account for underdrains
Bottom of the cell required 352.17 fmsl
SHWT elevation 350 fmsl
Distance from bottom to SHWT 2.17 ft OK
Internal Water Storage Zone (IWS)
Does the design include IWS Y (Y or N)
Elevation of the top of the upturned elbow 353.5 fmsl
Separation of IWS and Surface 2 ft OK
Planting Plan
Number of tree species 0
Number of shrub species 0
Number of herbaceous groundcover species 1 Recommend more species.
Additional Information
Does volume in excess of the design volume bypass the
y (Y or N)
OK
bioretention cell?
Does volume in excess of the design volume flow evenly distributed
N (Y or N)
Excess volume must pass through filter.
through a vegetated filter?
What is the length of the vegetated filter? ft
Does the design use a level spreader to evenly distribute flov?7 N (Y or N) Show how flow is evenly distributed,
Is the BMP located at least 30 feet from surface waters (50 feet 9 Y (Y or N) OK
SA waters)?
Is the BMP located at least 100 feet from water supply wells? y (Y or N) OK
Are the vegetated side slopes equal to or less than 3:1? y (Y or N) OK
Is the BMP located in a proposed drainage easement with access y (Y or N) OK
to a public Right of Way (ROW)?
Inlet velocity (from treatment system) 4,51 ft/sec Insufficient inlet velocity unless energy dissipating devices are
being used.
Is the area surrounding the cell likely to undergo development in N (Y or N) OK
the future?
Are the slopes draining to the bioretention cell greater than 20%? n (Y or N) OK
Is the drainage area permanently stabilized? y (Y or N) OK
Pretreatment Used
(Indicate Type Used with an "X" in the shaded cell)
Gravel and grass
(flinches gravel followed by 3-5 ft of grass)
Grassed Swale OK
Forebay X
Other
Form SW401 -Bioretention-Rev. 8
July 30, 2009 Parts I and 11. De"n Summary, Pape 2 of 2
Permit No
(to be assWed by DWQ)
Please indicate the page or plan sheet numbers where the supporting documentation can be found. M incomplete submifdtal package will
result in a request for additional infom>ation. This will delay final review and approval of the project Initial in the space provided to
indicate the following design requirements have been met. If the applicant has designated an agent the agent may initial below. If a
requirement has not been met, attach justification.
Pagel Plan
Initials Sheet No.
1. Plans (1' 50' or larger) of the entire site showing:
Design at ultimate build-out,
Off-site drainage (if applicable),
Delineated drainage basins (include Rational C coefficient per basin),
Cell dimensions,
Pretreatment system,
High flow bypass system,
Maintenance access,
Recorded drainage easement and public right of way (ROW),
Clean out pipe locations,
Overflow device, and
Boundaries of drainage easement.
2. Plan details (1' = 30' or larger) for the bioretention cell showing:
Cell dimensions
Pretreatment system,
High flow bypass system,
Maintenance access,
Recorded drainage easement and public right of way (ROW),
Design at ultimate build-out,
Off-site drainage (if applicable),
Clean out pipe locations,
Overflow device, and
Boundaries of drainage easement.

Alt Indicate the P-Index between 10 and 30
'
'
3. Section view of the bioretention cell (1
= 20
or larger) showing:
Side slopes, 3:1 or lower
Underdrain system (if applicable), and
Bioretention cell layers (ground level and slope, pre-treatment, ponding depth, mulch depth, fill media
depth, washed sand, filter fabric (or choking stone If applicable), #57 state, underdrains (if applicable),
@ e.,J SHWT level(s), and overflow structure]
fn ?In Mm?S4. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. The
r
results of the soils report must be verified in the field by DWQ, by completing & submitting the soils
investigation request form. County sal maps are not an acceptable source of soils information. All
elevations shall be in feet mean sea level (fmsl). Results of soils tests of both the planting sal and the in
situ sal must include:
Sal permeability,
Soil composition (% sand, % fines, % organic), and

3 - index.
'
5. A detailed planting plan (1
= 2(Y or larger) prepared by a qualified individual showing:
A variety of suitable species,
Sizes, spacing and locations of plantings,
Total quantity of each type of plant specified,
A planting detail,
The source nursery for the plants, and
Fertilizer and watering requirements to establish vegetation.
a"a^ 6t44? 6. An assurance that the installed system will meet design specifications upon initial operation once the
project is complete and the entire drainage area is stabilized.
7. A construction sequence that shows how the bioretention cell will be protected from sediment until the
entire drainage area is stabilized.
?1a 8. The supporting calculations (including underdrain calculations, if applicable).
'L 9. A copy of the signed and notarized inspection and maintenance (I&M) agreement.
/?f4
Form SW401-Boretenton-Rev.7
10. A copy of the deed restriction.
Part III, Page 1 of 1
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11t'1'nlll Nltnlht'r:
tt" be provozl"d AI Nf 0)
Orainau.v \rej tiumhtr. /
Bioretention Operation and Maintenance Agreement
I gill keep ?? l1winten.IIlk t• record on this BM P. I Ilis maintenance record %vill he kept in a
log ill a kr1own set location. Am deficient BNIP elelllents noted in tilt' inspection will be
corrected, repaired or replaced imnlediatehv. I liese deficiencies can affect the intes"I.1ty
of structures, safeth• of the puhlic, ?I11d the retnt,val efficierlcv of the WNW.
Important operation dnd m.1intenance procedUres:
Iill iiledIato Iv after the bioretention cull is established, the plants will he watered
twice twcAly if needed until the pl.1nts heconu' established (conl?11onk sip
lwet-ksj.
Snow, ?11u1ch or anw other material will N1 VFR he piled on the stn•fdce of the
hioretelltion cell.
110,1VV t'tlUipnlent twill NI TR he th•iVe?l ower the hiorete?ltion t(ll.
special tare Will he takt,n to provenf sedilllent troll) enterFll4; the bioretention cell.
(once a \ e'Ir,'I still test of the soil nletlia Will he conducted.
Alter the hioretentiorl tell is established, I will inspect it once a month and within 24
hours after every storm event greater than 1.0 inches (or 1.5 inches if in a Coastal
County). Records of operation and maintenance will he kept in a known set location
'Intl Will he awail<Ihk upon retlrlr•st.
Itlspectioll activitiCS ~11.111 he pertortllod 1% lollotvs. Ally problems that arc toured shall
he repairer{ imllledi,ltel. .
BMP ele tllent:
The entire BMP
The perimeter of the
bioretention cell
Potential problems:
rash j debris is present.
Areas of bare soil aild or
t•rosiwe gullies havr fc?rn?et1
Ilow I will renlediate the
-problenl:
Y_...._. ____ .„.__..._. _....._-__ _.._.
Retllove the trash/debris.
Regrade the soil it tw(essarv to
remove tilt- gull', anti then plant a
};round rover anti %\,Iter until it I-,
established. Provide lime and a
one-time tertilizer application.
Unclog the pipe. I )ispow of the
Sedillient oft-site.
Replace the pipe.
'file inlet device: pipe,
stone verge or swale
l roSiorl is ort urrinp, in tilt * Rew.'Itty the shale it ntcessarw to
stcale (it Ipplicabk ,)_ smooth it ower and provide erosion
control dewites Stith as reintorced
turf nlattitig or riprap to avoid
ttlture problerl?s twith erosiotl.
1-tetlt• wert,e is tlot'ged (It. Remove %editl?etlt anti clogged
towered in seditltent (it Stolle anti repute tt ith clean Stolle.
.1 pill it a NO
I he pipe is t foggod (it
applicable}.
Ihe pipe is tt'ackrd or
othertwise damat;ett (it
applitahle)
turol ?N`lttl-liioret?ntion t>t\\1?Rt•ti.?
I';l,?c l ol??
It'v1P element:
1'he pretreatment area
The bioretention cell
vegetation
1•he bioretention cell
,oil, and mulch
Potential problems:
Flmt iN bt pas,nl;;
prhtrt•atlit 'lIt .trt',I ,ntl/or
"LI it •, 1 1, I\ It 11-111 ek
It'tfilnent 11,1% ,It t tlmulated tit
a ticpth ;;I eatc? than three
Im Ilt•,
11w wn il,•, ott Urretf
It\tvd alt. pt'c%cllt
I;c,t proteNslrnal prat tit e,
,hott that prunin;; i, ncedt'd
to 111,6111.1111 optimal plant
health
PI'lnt, aw ttcati, tiisea,cli m
titim;
i'ce ,Llht•s I t\ ire, art` pt'h,cllt
,i? nlointh, alter plantinl•.
'hulk h IN hrcahrlr; titnt it oir
ha, 11"'Itt'd anat.
-ttil, .Intl t,r 1111161. It arc
t Itts,Ycti 1.t till "t'dillit'llt
\n annual Noll tc,t short, that
lt1 1 h„ tirt,ppt•tl (tr hh,ttt
metal., It,)%e It ttlltltllalt-d ill
the,ttll media
How 1 will remediate the problem:
Ket;ratlt• it netc,,,rt t„ route all
114m. to the pretreatment mv&
Rt,tabiliie the area attt'l 61atintt_.
`van It for the uluiyc of the
etii?tlent and relnellt titt• pl-Allem it
poiN,ihlh. Rvmott• the wdinwnt and
w%t,bili/e the IIIOlk•atlnt•nt area.
Prot itch additional erosion
ltrt,t(,rtit )II slit It ,N reintort ed turt
nl,ttinl, or riprap it nc('-dcd to
pw\k-tit future ero,ion proibfcm%.
hetttute the net'tf%. prt•terahlt Itt
haII&
I'l LIII ' at t ortiin}; loi lV%1 proh',Nioinal
brat tine,.
I )etermirlc Ihv smirtc ttl tht'
pittbit•liv 'wil,, ivYirttlttl;v, diNk"I"c'
t'tt. Ivvllltldt tit' prt,bleill and
It'plarh plant, Prtttitic a ttne tulle
lelIlliier,ppitatitm t1., e,tabliNh the
grlnlnd cover it a ,oil tt•,t indit att.,
it is net e„art .
Remove tive %take It Ire% ttt Rich
('111 hill the trr't• it not rl. inw, od).
tipot Itllllrh it there are unit rantlt,m
t Old are,,. IZe1110t e t?, ht,lc 1111.1It h
later it nt•tt'„art Rcmotte the
re11laiI I ing III 11t 11 anti It 'platt ,.6th
triple,Itrhdded 11a rd t,tu,d III It h at
a 111aVI11it III dek1tlt 1.,t three int heN.
I ?cter11tint' the c\tent 1.,t the rlttl?gitlI
icni ,\ h and rcplat'e either lu,t?the
to it, later, or the entire Illett[a ,t,
neetietl. I )I,po,t' ttt tht' ,pail 111 <ul
,pproipriate MI-Nite Iot,tion. L ,c
If Iplh,hrhdded harts v"It'd mutt It at
It 1111I\itnu?11 depth of thrty' lnnck,
1-t•art It Im. the mmit t` of the
,t'd111 'tlt.1111.6 rellit-d\ tilt' ltrt,ltlt'tll it
pw'slblc
I ?ttht11titit lime ,hall Ile applied as
rty t»rt11u'11ded lt.'r the NmI t(--,t and
tout ,oils ,hall It- I C1110% Vol,
th'-pttsed it l?roil>E'rlt and Ivplaoktd
1.t 6th nets hlalltill" Ilwdia-
I ornl ti\\-tUl-Itioroclitiml tWV-Kt•t., Pa?C tll
r
RMP element:
The underdrain system
(if applicable)
File drop inlet
The receiving water
Potential problems:
( loo"gins" hati 0(t urrt-d
( lo""gins; Itd? oc c u rrrd
I hc dresh inlet i% danla"k-d
Frrstiiun or other %igrls (it
datrla};t- havt- Ikl tit'rcld at the
Utltk -t.
I orm Skk 4o I -Morocntion ( I& Itc?,
flow I will remediate the problem:
\\&,h uut tilt- undordrain system
(1van out tilt, drop illk t. I )i.,posv of
tht- sedintrnt ott-%itv.
Repair or roplate the droll inlet_
( ontart the V I Ilivisitm of t%ah.r
Quality 401 (hcrtiight L)nit at `)Ic>-
7 'I-1i8h.
l':IL'i .? Ul ?+

1".•1.1111[ \u1111her
rl<<b, 1 -0 t,1I,/,,/i,i /111trt
I acknmN1c ,-,c and a-rcc h\ nl\ "iunaturv hei+t\\ that I am I-c"p ,n,ihlc li,r the
1\erlitrmancc of the maintcllarlcc procedures listed aho\c. I api-c ' to notit•\ D t) ol'an\
prohlcIns mill the s\Stem or (11'11+r to am chant-'es to the "\,1e111 Ur respon"Ibie 1%II.1\,
Proit-cl rramt.: 7 c/n Ci c/G/
B I /P drailla"C• rrrr?r rwnthcr
Adkircss:
Phone: q1 q 3i 3_ 3
.t
1'
tit,?trtturc: I 1
Date: / y G .l G'
I
Print n1lnc: A 1- f1t„ N.- N I1ie 1 _ /7 _ q-1
\ote: 111" Ie atl\ rc,lton,iMe pal I\ .h11ulJ 11411 he a 110111cok%[ICr, a11110OMion unless moue than of
Ihk. lot, 11.1\: been old and a 1?•,iklcnt 411 111e ,nhkfi, ikion 11.1" hCCII named the 1ue,iaem
\otarv Public fits- the State ol,
C( 1111, of ? r. do hcrehv certik that
her,onall\ appcarcd hetitrc me thi.
Slav of A0,1 ellvI acknovv (e,.i,?e the clue evecution of the
li1r?++im? him-1 ration 111amIcnancc re(luircn)eln.. 1i itne.. n» 1 \l anti official 'Cal.
MISSIE THOMON
NOTAW PUBC
Wake c"". NoM ONO"
2012
I E ws 14
MY
Sl AI
-_-
a Ur
M\ conlltlistiioll exhlres
1
I ortlt \\ 101-Iiir+t•<' oltiun I&%I-Itk•v. '
Pa??c -1 ++I•-1

ED ACS' UIRME
& ASSOCIATES, INC.
January 10, 20l t
Mr. Andrew N1. Rodak, P.E.
Dunklee & Dunham, P.C.
l 1 Keisler Drive, Suite t02
Cary, North Carolina 275 18
Re: Hydraulic Conductivity (Ksat) Testing
104 Aberson Court
Cary, Wake County, North Carolina
EA Project # 2011-002
Dear Mr. Rodak:
On Tuesday December 21, 2010 Ed Aguirre & Associates, Inc personnel conducted one (t) constant head
permeability tests on the referenced property to determine the saturated hydraulic conductivity at the expected depth
of the area of the proposed storm water disposal system.
Saturated hydraulic conductivity tests were performed to determine the permeability of the "BC" horizon at the
expected infiltration unit depth. Saturated hydraulic conductivity is a quantitative measure of a saturated soil's
ability to transmit water. It can be thought of as the ease with which pores of a saturated soil permit water
movement. A common method to measure saturated hydraulic conductivity (KsAT) of the unsaturated zone is by a
constant-head well permeameter method (Amoozegar and Mecklenburg, 1999). These KSAT tests take into account
soil morphologic factors other than texture, because soil structure and clay mineralogy have been found to have a
significant impact on the rate of water movement through soils (Bouma et al., 1983; Schoenberger et al, 199,
Vepraskas et at, 1996). The Compact Constant Head Permeameter (Amoozemeter) is an example of a constant head
permeameter which allows measurements of KSAT in the vadose zone and is widely used in North Carolina and other
parts of the country (Amoozegar, 2004; Amoozegar and Mecklenbur(y, t999).
The BC layer was encountered at a depth of 40-inches below natural grade in the proposed disposal area. Constant
head permeameter I (CHP- t) was run at a depth of 2-inches below grade in the proposed disposal area located at
the rear of the existing structure. This area was filled with soil from the grading of the residential structure's footing
and lot grading activities. The test hole reached steady state readings at five minutes and three consecutive readings
revealed a final conductivity of 0.213 inches/hour or 3.192 gallons per square foot/day. The water table was not
encountered at the finished depth of 52-inches in the test area.
1r IN-DINGS
The subject property contains soil belonging to the Urban soil series. The Urban complex soil is described
as being cut, filled, graded or otherwise changed to the extent that :he original soil characteristics have been
altered or destroyed. The underlying native soil has been exposed due to construction activities to reveal a
multi-colored sandy loam saprolite.
The soil was found to have a depth to seasonal high water table of 24-inches in the existing fill due to the
.'sponge effect" of the fill but >60-inches in the underlying native soil.
1300 C Corporation Parkway • Raleigh, NC 27610 • Tel: [phone] • Fax [phone]
P.O. Box 1304 • Colonial Heights, VA 23834-1304 • Toll Free [phone]
?1 r
Recommendations
To ensure that the storm water unit drains property, care should be taken to avoid compacting the soil
beneath the unit prior to nstallation to ensure proper drainage to the subsurface for the life of the project.
An under drain should be installed to ensure proper functioning of the unit.
The findings and recommendations presented herein are base} on the site conditions observed during
performance of the field testing on December 2l, 2010.
Please call me at [phone] if you have any questions or need fu ass4gance.
Sincerely, m? -d
Ed Aguirre & Associates, In
/- p
-<-E ward G. Aguirre, P.G. a?+ell,
Principal x 1 `J
David E. Meyer, L.S.S.
President % `cc: file

HYDRAULIC CONDUCTIVITY STUDY
104 Aberson Court Date: 12/21/2010 Weather Condition:
Location: storm water Temperature fl:
Number: 1
Horizon: C
)th(inches): 52.0 SET UP Target Water Level:
I'
Hole Depth (cm):
Reference (cm):
Head (cm):
CHT Tube(s) setting
Valve Setting:
Coversion Factor (C.F.)
cm inches eginning Water Leve .
132.1 52.0 Ending Water Level:
+ 14.0 5.5
- 17.8 7.0
;fear, Breezy
45
cm inches
17.8 7.0
15.2 6.0
17.8 7.0
= 128.3 Hole diameter (cm): 5.5
Hole radius (r): 2.75
x coefficient A: 0.000860
1-ON 2-ON
NOTE: Readings based on Ending Water Level
105.0
Water
Reading change in
water level Chamber
C.F. clock
time (min) Elapsed Time
(min) (hr) Q
(cm3/hr) K
(cm/hr) K
(in/hr) K
gal/ft2/day
47
5
46 0.0
0.5 105.0
105.0 0.0
5.0
5.00
0.083
630.0
0.5418
0.2133
3.192
.
46 0.5 105.0 10.0 5.00 0.083 630.0 0.5418 0.2133 3.192
45
5 0.5 105.0 15.0 5.00 0.083 630.0 0.5418 0.2133 3.192
.
45 0.5 105.0 20.0 5.00 0.083 630.0 0.5418 0.2133 3.192
44:5 0.5 105.0 25.0 5.00 0.083 630.0 0.5418 0.2133 3.192
Final Ksat 0.542 0.213 3.192