HomeMy WebLinkAboutDrainage Report - COM Engineering / Geo-Tech Reports - 12/14/2004 Michael F. Wnek, P.E., PS
Consulting Civil Engineer
1665 NW Sherwood Drive, Bremerton, WA 98311,360-692-3802
DRAINAGE REPORT RECEIVED
FOR A DEC 14 2004
COMMERCIAL BUILDING PERMFF w. CEaaIZ S-r
ON THE
WEST RAILROAD PARCEL
of the
CORBIT SITU'
Mason County, Washington
Prepared for:
S & J Johnson LLC
P.O. Box 488
Belfair, Washington 98528-0488
360-275-6734
CONTENTS
Tab-1..................... Drainage Narrative
Tab-2..................... Support Documentation
Tab-3..................... Hydrological Engineering Calculations
Prepared by:
Michael F. Wnek, P.E., PS
1665 NW Sherwood Drive
Bremerton, WA 98311-8941 � 01 �-
(360)-692-3802 0-3,560
December 11, 2004 ��"ty,4
Project#: 209
WEST RAILROAD PARCEL Michael F. Wnek, P.E. PS
Corbit Site,Mason County
Drainage Report December 11,2004
Tab-1
Drainage Narrative
TABLE OF CONTENTS
Page
1. Project Description& Information.......................................................................... 1
2. Downstream Conditions............................................................................................. 2
3. Existing Condition Basins.......................................................................................... 2
4. Soils............................................................................................................................ 2
5. Drainage Concept& Development Conditions.......................................................... 2
6. Water Quality............................................................................................................. 2
7. Erosion Control.......................................................................................................... 2
WEST RAILROAD PARCEL Michael F. Wnek, P.E. PS
Corbit Site,Mason County
Drainage Report December 11,2004
1. Project Description & Information:
Overview:
This parcel adjoins the "Corbit Site," a 43 acre site to the east that was permitted for clearing and
grading operations in 1995. Stormwater quantity control for the Corbit Site is provided by an
infiltration pond at the south end of the site (see: Phase-11 Drainage Report for General Site
Grading **Revision No. 1**, 10-27-1995, Olympic Engineering Inc.). The stormwater controls
for the subject parcel (herein referred to as the "West Railroad Parcel") are designed as a stand-
alone facility, since the topography and the railroad grade make gravity flow back to the Corbit
infiltration pond impractical.
Project Location: T 23 N, R 1 W, W.M., SECTION 21
Assessor's Parcel #: 12321-34-00010
Developer: S & J Johnson LLC
Parcel Acreage: 19.01 acres total; 9.63 acres west side of railroad tracks
Development Type: Commercial Building Permit
Proposed New Impervious Area: 0.54 acre
General Information:
The project is located in northeast Mason County. The existing access point is from State
Highway 3 northeast of the railroad overpass; approximately 2,000 feet southwest of the Log
Yard Road intersection.
The subject assessor's parcel spans both sides of the railroad right-of-way. The proposed project
occurs on the portion of the parcel west of the railroad.
The existing site vegetation is second growth timber with substantial brush and ground cover.
Topography& Basin Delineation:
The declivity of the topography of the project area is generally towards the west.
The steepest slopes within the project work area are less than 30%.
There are no upstream basins that effect the project, the railroad grade is the highest elevation in
the immediate vicinity.
1
WEST RAILROAD PARCEL Michael F. Wnek, P.E. PS
Corbit Site,Mason County
Drainage Report December 11,2004
2. Downstream Conditions: There are no known drainage problems downstream of the project.
3. Existing Condition Basins: Not applicable, see paragraph 5.
4. Soils: The soil type within the project site is of the Everett Gravely Loamy Sand series, or the
Indianola Loamy Sand series. These soils are considered Hydrologic Soil Group "A" for runoff
calculations.
Substantial soils testing was performed on the parcel in 1996 when a community septic drainfield
area was being explored for the Corbit Site. All soils were classified as sand or gravel, and no
seepage or hardpan layers were found at depths to at least 10-feet.
5. Drainage Concept & Development Conditions: The project creates over 10,000 square feet
of impervious area, and typically would warrant storm flow control.
However, the proposed project will change only 6% (0.54 ac. / 9.63 ac.) of the parcel area to
impervious area.
Additionally, the local soils are all in Hydrological Group "A" with excellent infiltration
potential.
Therefore it is proposed to use a passive system to mitigate storm runoff impacts from the
project, through the use of a 100-foot long dispersion trench.
Hydrology calculations, attached, show that the dispersion trench will infiltrate up to the 2-year
storm event. Overtopping of the dispersion trench by larger storms will not create flow depths
greater than 0.1-foot.
6. Water Quality: The runoff from the pavement areas will sheet flow through a grassy area
before entering the dispersion trench.
7. Erosion Control: Erosion control features include filter fabric fence below the fill slope area,
and re-vegetating all exposed soils.
\209\storm\209 W-RR DR.doc
2
WEST RAILROAD PARCEL Michael F. Wnek, P.E. PS
Corbit Site, Mason County
Drainage Report December 11,2004
Tab-2
Support Documentation
TABLE OF CONTENTS
EXHIBITS
EXHIBIT DESCRIPTION PAGES
A. USGS Map 1 page
B. Isopluvial Maps 3 pages
C. Soils Maps and Narratives 2 pages
D. Hydrological Soil Group Curve Numbers 1 page
E. Infiltration Rate Table 1 page
EXHIBIT A
S
At }b I 1 /.r'' USGS Ma
o
(71
-
- —f-• 1 _
LzderYl 4.
Mtn L¢,ke '1 Goa=� I
° r 1
nn W N
1It
+,
avet
i n
1 nU o 1
., -_-
r 'vel? y g
`C
� I {{{ sm 33�
It
IV k5
-
� .PROJECT s f
LOCATION 4D5 I
�✓, u � �f (1 "'__� caravel .: s f
o
1.
J �i�' �.�� 9f`1• D o '35' 1
elfair
r xHlBIT B
ns
S'TORMWATER MANAGEMENT MANUAL FOR STHEu vial a
PUG ET SOUND BASIN
124
- 49 l i23 122 121
25 sy .
j \ w suns s se is » to
} 6 E 71 s >a
OLGA , >• iy i 1`
i l r )",
\ FRIpAY HARBOR �PORT STA LEY
C jI T M, 30
d0
\} 1 V
b' 1 7S
� T
_35 3025Y0 J ^
., � 15 � t 10 � � : • �l 3
48 , R ' \�\l s•
yy
K wti
15
45 ; ` ` rouv% I 6 m
50 2S
eo �u;r,ui c c
S ss
ill 30
45 S AS N' 35.• AfC�i
1
35' 7 55 f �r 20
3 ` 45 40 35 r ' ACOMa 2 � —
47
u r
ag RDE N d
3025 s
s
CENT20
if S
YAKt
3
� Z0 /
35 N.. j ,(� :ADa
46 3 2 tB55
�/ r
WASHINGTON _ 25 B K
10 0 10 20 30 40 P.PL EN E
MILES 20 ' L11J10 15 /.
Figure 25 NOAA ATLAS 2, Volume Ix
ISOPLUVIALS F 2-YR 24•HR PRECIPITATI?N IN Prepared by U.S.Department of cc rnmerce
TENTHS OF A INCH NIVionst Oceanic and Atmosoherie ministration
IN Weather Service,Otfice of Hydrology
Prepared for U.S.Department of Alricuiture,
Soft Conservation Service,Engineer,rig Division
124 123 122 121
III-1-44 FEBRUARY, 1992
•-
20
17.5
1
i
�
VJJ• 1 / V • :�
" I .
f +
STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN
4 4 124 123 122 121
--
I
Et
�p 45 .• a ra-- �' 40
t ( 55HAR 4 lr
C� le
•10RT IzlArJi; \\\\
\ .
,!!)5 8085 \ 35 30 t ' t 0 5 a 01 c a
i—( 7 _ 5 10 6
25 I 4
55
48
T5 t a
80 y ss s
Lrt
45 t c s
1
001 Kra 56s , c ay 7 s
Q , �s
9Di•— i 40 80 i t o
t ? SI AT 5 1 is
�40Ai
4
1 rfV
LV
Ill 00�
\ �
47
AB£ODE >v
i `so. 2
/ 70 4 r 1 R t 0 sa is
�{ 75 _
2
ps 16
100 22 YAN
5'? f i •'•. � 45 1 ca c 70 0 s
I 55 3 ss t 40`s s 10
65 60 55�1� �0 ADdM (!�--30�
46 8
WASHINGTQN 40 s° 40
to� F EN _r
' 10 0 10 20 3tt 40 � 6� 2
MILES 40 a _ _ t;rau'r
. sssass
f Figure 30 ! I 45 ' 65 ; NOAAgATLAS 23 Vol um X
1SdPLUV1ALS F 100-YR 24-HR PRECIPITATION 5055 fi0 Prepared oce.;S Dae itn,a cne CC�ts�rn�+tfat}on
IN TENTHS OF N INCH National weather Service,Office oflIHyorosogy
Prepared for U.S.Department of A#ricutture,
i
Soil Conservation Service,Engineerog Division
124 123 122 121
III-1-46 FEBRUARY, 1992
EXHIBIT C
Soils Maps and Narratives
-
x
7.
gj
� .F� {�v zzr- R �,G 14,�':� ✓�:` �yCrii r �-� ,���1.�� q� �... ��t
� ^�-- J � � Ali F. ti - �\•'' �. tl� j s t' - �:�, �>
F \ t
-3N t
. .M...E� >•�-,tea r ���'��'�„ ' r-� �,� ,�
-!.c�y rs :- Y -✓ i�f� � _ F�;�, :r• y.. �! � � �.a r7 •yj"y-. w, �!a
�/ _� '1 r/1• '�3, t�J i -i 3✓. �<� 1����r � n�} � � �. � i� -Cy�,Y L.,
jj T
•j .Z.^ 4;f kT
,� '� f 3. "df°'`'x •,y , - �fe
, Y * W W
f -40
.e 3? ..J 'r''-ate "" ,+_ _ �e �(
glg
�"�� '.��X"�"'t yy � Y �T_� _ � - � �'4C�r 4��,�. ?x"' ��.t.''�.�1 f '""a w �y t��.c'�-•x,`c '.-4' �/ rl
h
'�'^.:.t �r.�- +eie 4`_ ` � rt i 1:. G J'a��� ✓�3# 'yr �i 3�e�'v "�'i -J.
•..� ?�� �� _ �r � 1 .� �v �r '_ I -•-���...--"mil �iY � � � W
M
r
Y/
^ [4
24 SOIL SURVEY SERIES 1051, No. 0
e Eld soil occurs only ill the extreme southern end material that is extremely loose Intl porous. Ilolvc
of tli county. It differs from the _Maxtown soils in in places, this Iaterial will stand ill banks. The c
hay-in'e ti redder surface soil and subsoil, some faintly of this material is largely determined by the gr:
- develope shot, and stronger reel and yellow Staining of coarse sand, and cobbles, which are olive gray,
the subsol . olive, yellowish browli, Iight brownish allay, Gray,
Eld silt I am, 0 to 3 percent slopes (Ec).—This soil is dark gray. Many of the cobbles, as well as illlie
15li of
at the head o yster Day. The surface soil is reddish- gravel, are faintly to moderately stained by iron.
brown, granular and friable silt loans, G to 10 inches The amount of gravel ranges from about 20 percei
thick, that contain a few very soft shot. This Iayer is 50 percent ill the subsoil to as much as So percent in
underlain by a reek ' I1-brown, firm clay loaln that has substratum. The soil is medium to strongly acid
a subangular blocky s • icture, is highly stained by iron, becomes less acid with dej?th.
alit- contains consiclerab amounts of-shot, At depths Use anrd su.i.tability.—'lliis soil is too clrongllty
r:ingimr from 0-0 to 32 11 'lies, the clav 10a111 rests oil most tilled crops—it dries out before crops gnat
a layer of fairy- con pact, st •lfified sane-and gravel tint Only a Very small acreage is cultivated, and thi
is prominently stained by iron. Rounded (r]acial gavel, ordinarily flirnled alum n•Ith better adjacent soils. -1
Mixed with subangular'ba.'altI anal el, is scattered on of this soil is in brush and trees, for �vhicil it is so
the surface glad- thl'011gll the soil. best. It is one of the better soils for nron•in« Doug
The soil is medium acid throu,,hoi surface dl•:lill, firs that are cut for Christmas trees. ' Phis is an ini�
is moderately well established, f7lolinll sira]es May tallt use of the soil; lal,;e acreages :ire used for Ch,
stay wet for a, ]ong tillie, Slibslll•fneO ( ••lillft'e is fairly mas trees.
Slow becallse of a slowly receding, fair Binh water This soil is ill capability subclass �%Is and in
table. class 4 for Dounlns-fir.
L',�c �nicl slritaLrlltrt.—host• of the soil i used for Everett gravelly sanely loam, 0 to 5 percent slo
11�Elsture or main. lfanagement is similar to that of iEg).—This soil occupies the smoother outwash terrace
ll-town sift loam, 0 to 3 percent slopes, but -H s are 'Issocintion with other ],verett soils. It differs fi
sli �lrily lower. Everett gravelly sandy 10:1111, 5 to 15 percent slopes
I lis soil is ill capability subclass IIIs; it is good r (],at its surface layer is generally 2 to 3 inches thiel,
;Is ,e, . tale profile is less variable; and the substratum, or un(
)yin« material is usl1,111) more stratified.
EVEI11:rT SERIES U;e and suitability.
-` Ile Ilse of this Soil is shililai
The. Everett series consists of somcwh;,t excessively 01A of 7;1erc�tt. g1:►tc11y sandy loam, � to 13 pert
drailled, pale-bro-Nvn gravelly soils. They occur as inex- slopes. 'i'he soil is in trees and l.lrnsll, except for a
tensive !-ravel rid`•es on the glacial moraines, (W. more sin:111 cleared areas. The ,solving of Dou:�las fir
conliloill�, as fairly continuous ontwash channels be- �'hrisfmas trees is gnilling ill impoi•tallce. This soil is
twec•n 1•iclges of _Llderwoo(l soils. Tliev have developed site class 4 for Doligdas-fir and in c•apabilify subel:iss
upon assorted glacial till and olltivasll material. The Everett gravelly sandy loam, 15 to 30 percent slo
rainfall is V..') to G0 inclies a ve:lr. The A•egetiition is (Ek).—This soil is on the steeper slopes of'g>•lacial i11onii1
mainly drou_�lit-resistant mndrone, inanrnnifa, and kin- sides of gullies, and terrace fronts. ]Cis closely ns
llikinrlick• V ciated with other ' Everett soils and the AlderlY1
Everett soils nre droughty because the loose gravel and gravelly candy loanis.
sand-y subsoil and substratuiil offer little resistallce to '_ This -,oil is more variable than Everett gravelly sai
downward movement of water. The capacity of the sur- Ioam, 5 to 15 percent slopes. The depth zo subistrat
face soil to hold available moisture is low. ran yes from 12 to 36 inches, and the amount of gra
I.vtrett soils are in the eastern half of tale county, in in the surface soil and subsoil varies greatly from pl
association with the Alderwood soils. They also occur to p�Iscc. Where the soil is in close a-,sociaiion with
-v in intricate patterns with the hits ip and Indlnnola soils. ;Llclerwood soils, the substratum, ill places, is c•onll,
Compared to the Grove soils, file Everett soils have ,Iand weakly cemented}.
Paler surface soil and subsoil Intl, in development, were Included are a few areas having slopes slid*litl_• `,ren
dominated more by acid igneous parent rock. than 30 percent.
Everett gravelly sandy loam, 5 to 15 percent. slopes Use and sv.rtabili.ty.—This soil is suitable only
fEh).—This is the mo--,t extensive -Everett soil. In Midis- forestry because it is strop 1y sloping►, drolighty, alid
turbecl forests 1 to 2 inclies of very dark grayish-brown in fertility. It is in capability sabcln-,s \GIs and ill
material, a Inixture of needles, leaves, twigs, cokes, moss, class 5 for Dom,las-fir.
and roots, covers the surface. The surface soil is loose, Everett gravelly loamy sand, 0 to 5 percent slog
single-brained, male-brown, ar:lV2II v sandy loani, G to 8 (Ed).—This soil occupies the smoother terraces or outw
inches thick. The upper 2 or 3 inches normally contains plains in close association with other Everett -,oils.
aggregates that nre slightly lmrd and recicler than tlie• differs from Everett gn velly sandy 1o:1m, 5 to 15 alert
others ill the layer. ` 0- depths ranginb froin 1S to 24 slopes, ill haviila a finer surface soil and a slip};
inches, the subsoil is loose, single-grained, light yellow- coarser subsoil.
is]z-bro«•n gravelly sand~' login or gravel-, loamy sand. Use mnd zr;f ,.bM*ty.-L:se and maiiageillent are sink
The amount of shot decreases withdepth; in the lower to those for Everett gravelly sandy ]one, 3 to 13 perc
part only a few shot occur, slopes. Thiss soil is poorer for forest than Evei
The subsoil grades to a substratui;z of poorly assorted, gravelly sanely login, 0 to 5 percent slopes. It is
Predominantly yellowish-brown snilcl, gravel, and cobbly capabifity subclass VIs and in site class 5 for Donglas-
EXHIBIT' D
Hydrological Soil Group Curve Numbers
STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASI
Table III-1.3 SCS Western Washington Runoff Curve Numbers
(Published by SCS in 1982) Runoff curve numbers for selected agricultural,
suburban and urban
land use for Type 1A rainfall distribution, 24-hour storm duration.
LAND USE DESCRIPTION CURVE NUMBERS BY
HYDROLOGIC SOIL GROUP
A B C D
Cultivated land(1) : winter condition 86 91 94 95
Mountain open areas: low growing brush & grasslands 74 82 89 92
Meadow or pasture: 65 78 85 89
Wood or forest land: undisturbed 42 64 76 81
Wood or forest land: young second growth or brush 55 72 81 86
Orchard: with cover crop 81 88 92 94
Open spaces, lawns, parks, golf courses, cemeteries,
landscaping.
Good condition: grass cover on z75% of the 68 80 86 90
area
Fair condition: grass cover on 50-75% of 77 85 90 92
the area
Gravel roads & parking lots: 76 85 89 91
Dirt roads & arking lots: 72 82 87 89
Impervious surfaces, pavement, roofs etc. 98 98 98 98
Open water bodies: lakes, wetlands, ands etc. 100 100 100 100
Single family residertial(2) :
Dwelling Unit/Gross Acre %Impervious(3) Separate curve number
1.0 DU/GA 15 shall be selected for
1. 5 DU/GA 20 pervious & impervious
2.0 DU/GA 25 portions of the site
2.5 DU/GA 30 or basin
3.0 DU/GA 34
3. 5 DU/GA 38
4.0 DU/GA 42
4.5 DU/GA 46
5.0 DU/GA 48
5.5 DU/GA 50
6.0 DU/GA 52
6.5 DU/GA 54
7.0 DU/GA 56
PUD's, condos, apartments, %impervious
commercial businesses & must be
industrial areas computed
(1) For a more detailed description of agricultural land use curve numbers refer
to National Engineering Handbook, Sec. 4, Hydrology, Chapter 9, August 1972.
(2) Assumes roof and driveway runoff is directed into street/storm system.
(3) The remaining pervious areas (lawn) are considered to be in good
condition for these curve numbers.
III-1-12 FEBRUARY, 1992
a.LLi aa1)j a L'
STORMWATER MANAGEMENT MANUAL FOR Intl- - Rate Table���.
Table III-3.1 Soil Properties Classified by Soil Texture
�� a
o �'
'v' < e < m m U U7an C] 4
x �
L
.0 U V V 1 r�i n N m O O O
3
C C
w Y�_" rr
w E
K "u >_ E 4 c 0 o O a o O o 0 0
W G. 33' v1 v'f �H �/1 vi �/1 v'1 �/1 V1 ./1 N ddo ^�
O U 6 V V '^ h n A A A A A A A � v
O.
w
v
C
w Q�
� C
C C
y C$
V
V
C • Q Y N it C H N
V, c c ry ee N N O C O O A O O O a
v
�u
w Y
V Y.
M �Y
G w
t 7
u
u >
C �
O •�
w
u �
w V
L Y
x w 8 u C
V U v x
.3 Y
y y U e U s H U
U +n N N Vnf V h h Vi C,J
III-3-8 FEBRUARY, 1992
WEST RAILROAD PARCEL Michael F. Wnek, P.E. PS
Corbit Site, Mason County
Drainage Report December 11,2004
Tab-3
Hydrological
Engineering Calculations
TABLE OF CONTENTS
Pages
BASIN PLAN WEST RAILROAD PARCEL....................................................................... 1
HydrologyCalculations.......................................................................................... 4
,
m
U)� v vT v
_- /O Vo v v
Q0 \ \
F-- \ I
1
� ST M `
1 � pER�i
l S ARE
4» �CRE
\ o
z
/ N
(�J
Z
i
— I \ O
I�
90 �_
\\ 90
BASIN PLAN
o.¢: S & J JOHNSON, LLC
MICNAEL F.WNEK,P.E.,PS _
� WEST RAILROAD PARCEL c�E�m ar: .0 P.O.eox 488
CORBIT SITE er: •'F'"' BELFAIR,WA 98528-0488
TJ
S7A7£H/CHWAY 3 a �Earar�i,w�OD s�ei�i QU-ar: zxw
Mxsw couHtt w�swHcrox ( )693-]B03 (360)-275-6734 (fax)-275-6775
HYDROLOGY CALCULATIONS
CORBIT SITE /WEST RAILROAD PARCEL
Project Precips
[2 yr] 3.50 in
[10 yr] 4.80 in
[100 yr] 6.80 in
[6 mo] 2.35 in
W-RR Event Summary
Event Peak Q (cfs) Peak T (hrs) Hyd Vol (acft) Area (ac) Method Raintype
6 Month 0.2833 8.00 0.1063 0.9400 SBUH TYPEIA
2 year 0.4774 8.00 0.1770 0.9400 SBUH TYPEIA
10 year 0.7236 8.00 0.2633 0.9400 SBUH TYPEIA
100 year 1.1295 8.00 0.4035 0.9400 SBUH TYPEIA
Record Id: W-RR
Design Method SBUH Rainfall type TYPE I A
Hyd Intv 10.00 min Peaking Factor 484.00
Abstraction Coeff 0.20
Pervious Area 0.40 ac DCIA 0.54 ac
Pervious CN 68.00 DC CN 98.00
Pervious TC 6.00 min DC TC 6.00 min
Pervious CN Calc
Description SubArea Sub cn
Open spaces, lawns,parks(>75% grass) 0.40 ac 68.00
Pervious Composited CN (AMC 2) 68.00
Pervious TC Calc
Type Description Length Slope Coeff Misc TT
Fixed MINIMUM 6.00 min
Pervious TC 6.00 min
Directly Connected CN Calc
Description SubArea Sub cn
Impervious surfaces(pavements, roofs, etc) 0.54 ac 98.00
DC Composited CN (AMC 2) 98.00
Directly Connected TC Calc
Type Description Length Slope Coeff Misc TT
Fixed _ MINIMUM _ 6.00 min
Directly Connected TC 6.00min
Record Id: INFILTRATE
Descrip: Infiltration in Sand Increment 0.10 ft
Start El. 100.0000 ft Max El. 105.0000 ft
Infiltration rate 8.2700 in/hr WP Multiplier 1.00
Stage Discharge Rating Curve
100.0000 ft 0.0000 cfs 102.6000 ft 0.1902 cfs
100.1000 ft 0.0901 cfs 102.7000 ft 0.1942 cfs
100.2000 ft 0.0941 cfs 102.8000 ft 0.1982 cfs
100.3000 ft 0.0981 cfs 102.9000 ft 0.2022 cfs
100.4000 ft 0.1021 cfs 103.0000 ft 0.2062 cfs
100.5000 ft 0.1062 cfs 103.1000 ft 0.2102 cfs
100.6000 ft 0.1102 cfs 103.2000 ft 0.2142 cfs
100.7000 ft'0.1142 cfs 103.3000 ft 0.2182 cfs
100.8000 ft 0.1182 cfs 103.4000 ft 0.2222 cfs
100.9000 ft 0.1222 cfs 103.5000 ft 0.2262 cfs
101.0000 ft 0.1262 cfs 103.6000 ft 0.2302 cfs
101.1000 ft 0.1302 cfs 103.7000 ft 0.2342 cfs
101.2000 ft 0.1342 cfs 103.8000 ft 0.2382 cfs
101.3000 ft 0.1382 cfs 103.9000 ft 0.2422 cfs
101.4000 ft 0.1422 cfs 104.0000 ft 0.2462 cfs
101.5000 ft 0.1462 cfs 104.1000 ft 0.2502 cfs
10 1.6000 ft 0.15 02 cfs 104.2000 ft 0.2542 cfs
101.7000 ft 0.1542 cfs 104.3000 ft 0.2582 cfs
101.8000 ft 0.15 82 cfs 104.4000 ft 0.2622 cfs
101.9000 ft 0.1622 cfs 104.5000 ft 0.2662 cfs
102.0000 ft 0.1662 cfs 104.6000 ft 0.2702 cfs
102.1000 ft 0.1702 cfs 104.7000 ft 0.2742 cfs
102.2000 ft 0.1742 cfs 104.8000 ft 0.2782 cfs
102.3000 ft 0.1782 cfs 104.9000 ft 0.2822 cfs
102.4000 ft 0.1822 cfs 105.0000 ft 0.2862 cfs
102.5000 ft 0.1862 cfs 105.1000 ft 0.2902 cfs
105.0000 ft 0.2862 cfs
Record Id: TRENCH
Descrip: Infiltration Trench Increment 0.10 ft
Start El. 100.0000 ft Max El. 104.0000 ft
Length 100.0000 ft Width 4.5000 ft
Catch 40.0000
Stage Storage Rating Curve
100.0000 ft 0.0000 cf 102.1000 ft 378.0000 cf
100.1000 ft 18.0000 cf 102.2000 ft 396.0000 cf
100.2000 ft 36.0000 cf 102.3000 ft 414.0000 cf
100.3000 ft 54.0000 cf 102.4000 ft 432.0000 cf
100.4000 ft 72.0000 cf 102.5000 ft 450.0000 cf
100.5000 ft 90.0000 cf 102.6000 ft 468.0000 cf
100.6000 ft 108.0000 cf 102.7000 ft 486.0000 cf
100.7000 ft 126.0000 cf 102.8000 ft 504.0000 cf
100.8000 ft 144.0000 cf 102.9000 ft 522.0000 cf
100.9000 ft 162.0000 cf 103.0000 ft 540.0000 cf
101.0000 ft 180.0000 cf 103.1000 ft 558.0000 cf
101.1000 ft 198.0000 cf 103.2000 ft 576.0000 cf
101.2000 ft 216.0000 cf 103.3000 ft 594.0000 cf
101.3000 ft 234.0000 cf 103.4000 ft 612.0000 cf
101.4000 ft 252.0000 cf 103.5000 ft 630.0000 cf
101.5000 ft 270.0000 cf 103.6000 ft 648.0000 cf
101.6000 ft 288.0000 cf 103.7000 ft 666.0000 cf
101.7000 ft 306.0000 cf 103.8000 ft 684.0000 cf
101.8000 ft 324.0000 cf 103.9000 ft 702.0000 cf
101.9000 ft 342.0000 cf 104.0000 ft 720.0000 cf
102.0000 ft 360.0000 cf 104.1000 ft 738.0000 cf
Record Id: LPOOL
Descrip: Level Pool Routing Increment 0.10 ft
Start El. 100.0000 ft Max El. 105.0000 ft
Storage Node TRENCH Discharge Node INFILTRATE
LPOOLCOMPUTE [LPOOLI SUMMARY using Puls
Start of live storage: 100.0000 ft
Event Match Q (cfs) Peak Q (cfs) Peak Stg(ft) Vol (cf) Vol (acft) Time to Empty
6 Month 0.2833 0.1538 101.6907 304.33 0.0070 24.67
2 year 0.4774 0.2393 103.8273 688.91 0.0158 24.67
10 year 0.7236 0.3578 106.7907 1222.33 0.0281 24.67
100 year 1.1295 0.5586 111.8079 2125.42 0.0488 24.83
TOP OF DISPERSION TRENCH = 104, STORMS UP TO 2-YR WILL INFILTRATED W/O
OVERTOPPING THE DISPERSION TRENCH.
Record id: WEIR
Descrip: Dispersion Trench Overflow Increment 0.10 ft
Start El. 104.0000 ft Max El. 105.0000 ft
Length 100.0000 ft cd 3.22
Stage Discharge Rating Curve
104.0000 ft 0.0000 cfs 104.6000 ft 149.4662 cfs
104.1000 ft 10.1699 cfs 104.7000 ft 188.3489 cfs
104.2000 ft 28.7648 cfs 104.8000 ft 230.1182 cfs
104.3000 ft 52.8443 cfs 104.9000 ft 274.5869 cfs
104.4000 ft 81.3591 cfs 105.0000 ft 321.6000 cfs
104.5000 ft 113.7028 cfs 105.1000 ft 371.0266 cfs
105.0000 ft 321.6000 cfs
PROJECT 100-YR PEAK FLOW= 1.13 cfs, LESS THAN 0.1-foot FLOW DEPTH FROM
DISPERSION TRENCH.