HomeMy WebLinkAbout41 Development Permit 0045 Westchester Park Phase 1DRAINAGE REPORT
for
L.OT lR, BLO.CK 1 .. {24.74-4 ACRES)
WESTCHESTER PARK -
PHASE ONE
JU.NIOR HIGH SCHOOL
JULY, 1989
OWNED AND DEVELOPED BY :
COLLEGE STATION IND. SCHOOL DISTRICT
1812 WELSH
COLLEGE STATION , TEXAS 77840
PREPARED BY :
KLING ENGINEERING & SURVEYING
4101 TEXAS AVENUE
BRYAN, TEXAS 77803
Drainage Report
for
Lot 1 R, Bloc k 1 , ( 24. 7 44 Acres)
WESTCHESTER PARK -PHASE ONE
College Statio n, Texas
Jul y 3, 1 989
INTRODUCTION
Lot l R i s the s i te for the J uni or Hi gh Schoo l. lmprovanents consist of
40 , 000 ft 2 li ght ly 1 oaded s i ng l e story structur e , 12 5 par king spaces a nd
associated infrastruc ture . The s ite is l ocated on the southeast s i de of Rock
Pra i r i e Road, approxi mate ly 0.25 mil es southwest of Rio Gr a nde Bou l evard . The
s i te is i n the Lick Creek drainage basin, near the head water s. In th i s area,
Ri o Grande Bo u levard i s a pprox imate ly on the drai nage div i de between Lick Creek
basin and Bee Creek basin . This s i te is considered to be in the secondary
dra i nage s y stem whi c h i s sens itive t o s hort durat i o n, hi gh intens i ty ra i nfall
events.
PRE-DEVELOPED CONDITIONS
The 24 .744 acr e site was d i v i ded into a nort heast and southwest dra i nage
area .
NE Drai nage
Area
10.7 Acres
L = 1520
S l ope= 1.5%
t c -21 mi n.
0 10 = 19.4 cfs
StorrT'fn'ater Flow i s to
ditch along Arnold Road,
then northeast along Road.
Pre-Developed Tota l Q10 = 4 1 cf s.
SW Dra i nage
Area
14.0 Acres
L = 1720
Slope = 1. 1%
t r -29 mi n .
Q,; = 21 .6 cfs
Stor ~ater flow i s to ditch
a l ong Arnold Road , then north-
east along Road to 2-42" RCP
which discharge in ditch along
Schaf fer Road.
K ling Engineering & Surveying
The existing soil conditions are as follows:
A thin fine sand which varies in thickne ss fran 12 to 15 inches.
This sand overlays on Lufk in series clay which has very slow internal
drainage and is susceptibl e to erosion on sl opes gr eater than 1%.
The vegetation on t he s ite is natural grassland.
Jerry Bishop and Associ ates, In c., prepared a drainage report dated
September 11, 198 4, on Family Tree Phase I , whi ch later became West c hester
Park Phase I. A 4' wide flat bottan di t ch with 4: 1 side slopes wa s
constructed along the caTTTOn line between Westchester Park and the school
site. A review of the Bishop Report indicates the followin g:
• Design Frequency -5 yr.
• U 1 t imate Deve 1 opment F 1 ow at Qs = 110 . 85 cf s (design) south corner
of school site (i.e. intersection of 4 foot ditch with 3 foot
ditch a long Arnold Road.
• Ultimate Development Flow at Qs = 119. 19 cfs (design) at 2-42" RCP
at intersection of Arnold Road and Schaffer Road.
• Di t ch Along Arnold Road -3' bottan with 3:1 side slopes.
• 12.22 Acres (V,W ,X,Y) of school site would discharge into
2-42" RCP at intersection of Arnold Road and Schaffer
Road Qs = 42 cfs, [using tc = 13 min, this is a time carpatible
to area T.U., see Bishop Report].
Rock Prairie Road is the boundary on the northwest and is a parkway (80
foot right-of-way, 56 foot pavanent) which has a crest approximately in the
center of the school site , t herefore, no f uture additional flows can be expected.
The 4 foot bottan earth channel i s the boundary o n the southwest, t hi s
channe 1 is constr ucted with 4: 1 s ide slopes and has .. a Qs design f 1 ow of 110. 85
cfs .
The 3 foot bottan earth channel in the right-of-way of Arnold Road is the
boundary on the southeast. This channel is constructed with 3:1 side slopes and
has a Qs desi gn flow of 119.19 cfs.
The soccer/baseball fields in Southwood Ath l etic Park ar e the boundary on
the northeast . Drainage of these fields is northeast or away fran the school
s i te .
In sunnary:
• 0 10 Pre-Development for the 24.7 acre school site is 41 cfs.
• This site is near the drainage divide, therefore, no future flows can
be expected across the school site.
• The as-built O/barrel of the existing 42" RCP is 150 cfs/barrel. Total
O = 300 cfs through 2-42" RCP, assL111ing E.G.L. equal to pipe slope.
Existing velocity 17ft;s.
• Southwest Drainage Area flow through 2-42" RCP with 0 10 = 21.6 cfs.
Northeast Drainage Area flow to ditch section in Arnold Road then
northeast along Arnold Road O:o = 19.4 cfs.
The 0 1c flows given are fran the school site only and do not include flow
fran Westchester Park.
POST-DEVELOPMENT
The 24.7 acre school site has been divided into 9 drainage areas. Dra i nage
Areas I through V being the intensely developed portion of the site, wi th
Drainage Areas VI through VI I I being grass areas.
DRAINAGE AREA I -This area is street and service anployee parking and
will drain via 3 -4 foot wide curb cuts to the ex i sting
4 foot bottan earth channel. This flow wi 11 by-pass the
detention pond. I 0'.c = 4.19 cfs
DRAINAGE AREA I I -This area is two tennis courts wh ich drain to a swale
adjoining the northeast property line then to the ditch
in Arnold Road and then northeast along Arnold Road.
Thi s flow will by-pass the detent i on pond.
I I O;o = 2. 4 cf s
DRAINAGE AREA I I I -This is the southwest half of the school building and
associated green spaces, wa l ks, and drives . This area
drains via a grate inlet/storm sewer system to the
terminat i on of Dra i nage Area 111 at the area i nlet prior
to the headwa 11 at the detention pond. Pipe sizes range
from 15" to 27" RCP. There are 8 sub-basins within
Dra inage Area I I I, each of which have been provided a
gravity overflow path for events greater than the 10 year
and at an elevation below 321.0. The school building
is at 321 .0 finish floor, all grass areas adjoining
building begin at 320.5, and have a 1% slope to area
in l ets. 111 O·l'I = 25.94 cfs v
DRAINAGE AREA IV -This is the northeast half of the school building and
associated green spaces, walks, and drives. This area
includes the bus loop and 91 space parking lot. This
area drains via a grate in let/stonn sewer system to the
tennination of Dra inage Area IV at area inlet between
the tennis courts and parking lot. Pipe s iz es range fran
15" to 27" RCP. There are 11 sub-basins within Drainage
Area IV, each of which have been provided a gravity
overflow path for events great er than the 10 year and
at an elevation be low 321.0. IV Q'.O = 28.89 cfs
DRAINAGE AREA V -This area is the two tennis courts and green space which
adjoins the two tennis courts in Dra inage Area 11. Thi s
area wi 11 drain to swale at the beginning of the
detention oond and into the oond. V Q·~ = 2.66 cfs • • t ~
DRAINAGE AREA VI -This area is the 1.0 acre detention pond and adjoining
grass land. The detention pond has the fol lowing
characteristics:
• Q,~ -73.64 cfs
• .J
• Elevation 2-27" RCP which discharge t o detention pond
Elevation -310.35
• 0.6% Slope (Bottan Slope) on 8 foot wide ''V'' Section
low flow inv e rt Q = 20 cfs
•S ide Slope -i2:1
• "V" Notch we ir control structure flow line elevation
307 .38, Top "V" Elevation -310.55, To p box Elevation
-311. 1, Q = 20.5 cfs (rel ease rate)
•Top Embankment -Elevation -31 1.2
•Discharge pipe 36" RCP at 1.0% slope , L=35, tenninate
in face ditch slope in Arnold Road in line with 2-42"
RCP, elevation 307.0
•Top 2-42" RCP , elevation 307. 1 -discharge into
northeast ditch of Schaff er Road
This area wi 11 discharge into the 2-42" RCP at the inter-
sect ion of Arnold Road and Schaffer Road having a slope
of 1.9%, L=45, Q ... 0 ... ~1 c~"ac ;4 Y = 300 cfs. Ther e are 3 sub-\,, \..C. 1 C,U I \,,
basins withi n Dra i nage Area VI, two of wh ich are small
areas behind the detention pond.
DRAINAGE AREA VI I -This area is 2.61 acres at the low point of the school
site. It is to be left in its existing condition with
no known future plans, except to be used as a play area.
This area will sheet flow to the ditch in Arnold Road,
then northeast along Arnold Road. This flow will by-
pass the detention pond. VI I 0 10 = 6.76 cfs
DRAINAGE AREA VI I I -This area is 3.78 acres at the south corner of the
school site, will be used as a spoil area, excess fill
fran building will be placed/canpacted consistent with
future football/track field. This area will sheet flow
to ditch in Arnold Road, then to 2-42" RCP at Arnold and
Schaffer Road. This flow will by-pass the detention
pond. VI 11 Q ,0 = 14. 7 cfs
DRAINAGE AREA IX -Th i s area is the existing 4 foot bottan with 4:1 side
slope earth channel a long the southwest line of the
school tract. This flow wi 11 by-pass the detention pond.
The Drainage Areas contributing to the flow t h rough the 2-42" RCP are I,
I I , I I I , IV, V, VI , VI I , VI I I , and IX having a Q i o = 96. 63 cf s.
To account for head loss at inlets, 0. 10' fall through each i nlet has been
provided.
It is recognized that 15" and 27" RCP are not standard sizes. These sizes
were required by the lack of head available fran finish floor of the 500 foot
long building to the flow line of the 2-42" RCP.
A review of the inflow/outflow simulation will indicate a required storage
volume of 351,707 ft3 design capacity, the provided capacity to elevation 311 is
78, 100 ft .
The analysis of the 100 year overflow conditions at the detention facility
has assL.med all of the embankment will be used as a weir, with a depth of flow
over the embankment of less than 0.5 feet . This overflow will then flow to the
ditch in Arnold Road.
SUMMARY
• o1o Post-Developnent for the 24.7 acre school site is 105.78 cfs.
• O;c to the detention pond is 73.64 cfs.
• o1o which by-pass detention pond is 32. 14 cfs.
• Release Rate ''v'' notch weir is 20.5 cfs.
• 1 .0 Acre detention pond will reduce the peak flow Post-Developnent
from 105.8 cfs to 52.6 cfs.
• The existing 2-42" RCP which serve as the outfall structure for most
of this project has a Oto:a · ca c ac'ty = 300 cfs. Bi shop's Report
ind i cates 0; = 119.2 cfs and th i s reoort ind i cates O·~ = 96.63 cfs from
school site ~only and does not include any flow from JWestchester. It
appears that the as-bu i 1 t frequency of the existing 2-42" RCP is between
5 and 10 years.
• No future flows can be expected across th i s site by virtue of Rock
Prairie Road be i ng on a crest adjoining the school site.
Kling Engineering & Surveying
FORMUL AE
In determining the amount of storm runoff fran the school site, the
Rationa l Meth od has been incorporated. This method is expressed by the fonTLila:
Q
where: Q
c
A
=
=
=
CIA
discharge, in cfs (cubic feet per second)
runoff coefficient (see page 23 o f the Co l ege Station
Drainage Policy and Design Standards)
= rainfall intensity, in i nches per hour (var i es with design
frequency and time of concentration, which is the time in
minutes required to dra i n the farthest reg i on o f the dra i nage
area, see page 27 of the Co 11 ege Stat i on Dra inage Po 1 icy and
Design Standards)
= drainage area, in acres
For analyzing the flow through parking l ots, swales and cul verts, Manning's
fonTLila has been used. This formula i s e xpressed as:
Q = 1 . 486 AR2 /3 s ,/2
n
where: Q = discharge, in cfs
A = cross-sectional area of flow, i n square feet
R = hydraulic rad iu s
s = slope of the e nergy gradient (usually parallel with the
s l ope of the channel bot tan)
n = Manning's Roughness Coeff i cient
For determining the flow through grate inlets, the standard or i fice flow
equation has been used:
Q = CA 2gh
where: c = discharge of coefficient 0.6
A = area of opening
g = acceleration due to grav i ty
h = head water depth
For determining the flow through ''V'' notch weir, the fol lowing has been
used:
Q = 2. SH 2 · S fan 0/2
where: Q = discharge cfs
H = head or weir (ft)
0 = angle of notch in degrees
For detennining the flow across the detention errbankment , the following
ha s been us ed:
, ::
Q = CLH '·.J
where: Q = discharge coefficient
= 3.27 + 0.40 ti
p
L = effective length of crest
H = head on the crest
p = height of the weir (embar>kment)
DRAINAGE WEJ.G~TED
AP.EA . I c'
-~
I S.W. 0.30
II N.E. 0.30
TOTAL ACRES
W u;-rc~ILSlc K
PA~K
RUNOFF COMPUTATION
"PRE-DEVELOPMENT"
AREA RUN/ v Tc I
(ACRES) SLOPE 1/ssc. Ml :N .• 1 0
14 1760/1 .05 % 1. 0 29 5 .14
10 . 7 1520/l . 5 % 1. 2 21 6.05
24.7 TOTAL DISCHARGE
<E-COR EY DRIVE
---------------~--
ROCK PRAI R\.L ROAD
-----,,-----------L ~-·-· ··------------
\ rl SOUT~vJ cs-r \ NO IT~EAS~
. D\{AI N .. r, ·L.. O RAi N AGt
I' ' -> A RC A
I /\k':A \
\
\
Q Q
1 0 IP
CFS CFS
21.6 ....
19. 4
i 41. 0
--
.So Vf\.-\ vJ OOD
AT~L C Tlt
PA RK
Q Q
5 Q 1 0 0
CFS CFS
27.68 31. 08
25.26 27.93
RUNOFF COMPUTATION
Page l of 3
"POST-DEVELOPMENT"
DRAINAGE · WE} G~TED AREA RUN/ v Tc * I Q >-Q Q Q
AREA . 'c' (ACRES) SLOPE 1 /sr::.c MIN, I 0 I 0 -1 0 5 0 I 0 0
CFS CFS CFS CFS
I-A 0.90 0. ll 180/0.6% l. 7 l. 7 8.63 0.85 0.85 l. l 0 l. 22
I-8 0.90 0. 12 185/0. 75 % 2. l l.5 8.63 0:. 93 0.93 l. 20 l. 33
I -C 0.90 0. 31 340/ l . 6% . 4.5 l. 3 8.63 2 .41 2 .41 3 . ll 3. 4 3
II 0.77 0.36 220/l .8% 4.7 0.8 8.63 2 .39 8.69 3.09 3.41
•III-A 0.5 7 0.37 140/2% 4.3 0 .5 8.63 l. 82 1.82 2.35 2. 59
•III-8 0 .34 0.88 120/6% 4.0 0 .5 '8. 63 2 .58 4.4 3.34 3.68
•III-C(l) 0.63 0.62 ll 0/1 % 2. l 0.9 8 .63 3.37 3.37 4.36 4.80
•rrr-c(2) 0.22 0.34 100/5.2% 4.0 0.4 8 .63 0 .64 8.41 0.83 0.92
•rrr-0(1) 0.59 0.90 120/0.8% l. 6 l . 3 8 .63 4 .58 4.58 5. 92 6.53
•r II-D ( 2) 0. 22 0.25 100/3.5% 3.0 0.5 8.63 0.47 13. 46 0.61 0.68
•III-E 0.70 0. 50 100/2% 4. 3 0.4 8 .63 3.02 116. 48 3.90 4. 31
•I I I -F 0. 18 0.63 180/l.7% l . 4 2. l 8.63 0.98 17.46 l.26 l. 39
•II I-G 0.63 l.56 320/0.7 % l.5 3.6 8.63 8 . 48 48.53 10.96 12 .0 9
* For all Tc less than 10 minutes, use 10 minutes.
• 010 = 73.6 4 cfs to detention (16.65 Acres, Cave = 0. 5 6)
.. •' ~
> •I > '<. • 0 -"<' .. > ~· &... .,:,•,• o .... t ................ .,, ..... U~--· ' "-I 0 • •
RUNOFF COMPUTATION
UPOST-DEVELOPMENTU Page 2 o'f 3
DRAINAGE WEJ,G~TED AREA RUN/ v Tc* I Q ~Q Q Q
AREA I c I (ACRES ) S LOPE 1/sEc MIN .• I 0 I 0 I P 50 I 0 0
CFS CFS CFS CFS
• IV-A 0.62 0.61 160/1 % 2. l l. 3 8.63 3.26 3.26 4.22 4.65
• IV-B 0.22 0.35 120/ 3% 3.0 0.7 8.63 0.66 3.92 0.86 0.95
• IV-C(l) 0 .61 0.62 l 00/l % 2 . l 0.8 8.63 3. 31 3. 31 4 .29 4.73
• IV-C(2) 0.61 0.22 200/0.5 % l. l 3 .0 8.63 l. l 6 8.39 l.50 l.65
• IV-D(l) 0.60 0.87 120/0.8% l. 7 l. 2 8.63 4 .50 4.50 5.82 6.42
• IV-0(2) 0. 71 0.50 200/0.75 % l.6 2. l 8.63 3.06 15. 95 3.96 4.37
• IV-E 0 .65 0. 14 75/2.5 % 5.3 0.3 8.63 0.79 16. 74 l. 01 l. 12
• IV-F(l) 0.90 0.51 260/l .4 % 4 .0 l . l 8.63 4.00 4.00 5 .12 5. 65
• IV-F(2) 0.90 0.59 300/2 .0% 5.7 0.9 8.63 4.58 4.58 5.9Z 6.53
• IV-F(3) 0.30 0.89 600/l. 37 % l.5 6.7 8.63 2.30 10.88 2.98 3 .28
• IV-F(4) 0 .25 0.59 180/3.6 % 2.3 l. 3 8.63 l.27 28.89 l. 64 l. 81
• v 0. 56 0.55 220/l . 6% 3.2 l. l 8.63 2.66 2.66 3.43 3.79
•VI-A 0.45 4 . 16 600/3 % 2.0 5.0 8.63 16. 15 67.34 20.87 23.03
*For a 11 Tc less than 10 minutes, use 10 minutes.
• Q10 = 73.64 cfs to detention (16.65 acres, Cave = 0 . 5 6)
RUNOFF COMPUTATION
uPosT-DEVELOPMENTu Page 3 of 3
DRAINAGE WEJiG~TED AREA RUN/ v Tc* I Q _LQ Q Q
AREA 'c' (ACRES) S LOPE 1/se:.c MIN .• I 0 I 0 10 5 0 I 0 0
CFS CFS CFS CF S
VI-B · 0.45 0. 16 150/2 .5% 2.0 * 8.63 0.6 0.80 0.89
VI-C 0.45 0. 10 120/0.3 % 2.0 * 8.63 0;.4 0.50 0.55
VII o. 30 2. 61 480/0. 9% . 0.9 8.9 8 .63 6.76 8.73 9.63
VII I 0.45 3.78 930/1 .0% 2.0 7 .7 8.63 14. 7 18. 97 20.92
0.30 1. 21 1130/1. 3% 2.0 9.4 8.63 3. 1 4. 05 4.46
TOTAL ACRES 25. 41 TOTAL DISCHARGE 105. 78 1 36. 70 150. 81
*For all Tc less than 10 minutes, use 10 minutes.
Drainage Areas I, II, VI-B, VI-C, VII, VIII, IX by-pass detention pond having total 010 = 32.14 cfs.
The release rate of the "V" notch weir is 20.5 cfs.
VOLUME SUPPLIED BY 10 YEAR STORM
CA = 9 .32
O UTFLOW
s x MIN = FT 3 I 7. 8 6 CFS QI 0 FT 3
MIN CA x lzs x 60 M I N
3
6 9.32 x 10.40 x 60 x 6 34,910 6,430 : 28,380
9 9.32 x 9. 01 x 60 x 6 = 45,360 9,644 35 , 715
1 2 9. 32 x 7.98 x 60 x 6 = 53,570 12,860 40,710
15 9.32 x 7. 19 x 60 x 15 = 60,335 16,074 44,261
18 9. 32 x 6 .56 x 60 x 15 = 66,060 19.2 90 46. 770
21 9.32 x 6. 05 x 60 x 21 = 71 • 080 22 ,504 48,576
24 9.32 x 5. 62 x 60 x 21 75,460 25. 718 49,742
27 9.32 x 5.25 x 60 x 21 = 79,300 28 ,933 50,367
30 9.32 x 4.94 X 60 X\30 = 82,910 32,148 50,762*
33 9.32 x 4.66 x 60 x 30 = 86,030 35,363 50,667
36 9.32 x 4.42 x 60 x 30 = 88 ,980 38,577 50,403
39 9. 32 x 4.21 x 60 x 30 = 91 • 815 41,792 50. 02 3
42 9.32 x 4. 01 x 60 x 42 = 94, 180 45,007 49,173
45 9.32 x 3.84 x 60 x 42 = 96.630 48 ,222 48.408
*Preliminary Volume re qui red 50, 762 ft 3 plus 10 3 .
DETENTION POND ACCUMULATED VOLUMES
AJ ACCUMULATED
E L EVA TI ON A R EA Al,
2 V O LUME V OL UME
(FT2) ( FT 2 ) (FT 3 ) (FT 3 )
307.4 0 0 0 0
308 5 '350 2,675 1'338 1 ,338
308 .5 10'400 7' 875 3,938 5 ,276
309 18, 125 14,263 7, 1 31 12,407
309.5 25,000 21,563 1 0, 781 2 3, 188
31 0 33,925 29 ,463 14,731 37,919
310. 5 40,000 36,963 l 8' 481 56,400
311 46,800 43,400 21,700 78 , l 00
TOTAL AVAILABLE STORAGE -78 'l 00 ft3
Top of Berm Eleva~ion -311 .2
DETENTION POND
. INFLOW/OUTFLOW SIMULATION
Page l of 2
TIME ~IN 6VIN + V ; v Q v TOTAL v STORE AVG HW OUT OUT STORE
(Ml N) (CF) (CF) (CF) (FT) (CFS) (CF)
v OUT (CF)
0 0
34' 910 17' 45 5 l. 6 3.8 1368 1368 33,542
6 34 '91 0
43,992 38,767 2.65 13. 3 2400 3768 41 ,592
9 45,360
49,802 45,697 2.75 14.6 2631 6399 43,403
12 53,570
50,~l 68 50,553 2. 95 17. 4 3136 9535 47 '032
l 5 60,335
52 '75 7 5 3 '662 3.05 18.9 3409 12' 944 49,348
1 8 66,060
54,368 55,626 3. l 19. 7 3550 16 ,494 50,818
21 71,080
5 5, l 98 5 6, 776 3. 13 20.2 3637 2 0, l 31 51,561
24 75 ,460
DETENTION POND
. INFLOW/OUTFLOW SIMULATION
Page 2 Oif 2
6v 1 N
I
VIN + V ; v Q v TOTAL v TIME STORE AVG HW OUT OUT STORE
(MIN) (CF) (CF)
v
(CF} (FT) (CFS) I CF I OUT (CF)
55,401 57,249 3. 15 20.5 3695 23,826 51 '707
27 79,300
5 5 '31 7 57,279 3. 15 20.5 3695 27 ,521 51 '622
30 82 '91 0
54,742 56' 949 3. 13 20.2 3637 31 '15 8 51 '1 05
33 86,030
54,055 56,347 3 .13 20.2 3637 34' 7 95 50,418
36 88,980
5 3 '25 2 55 ";602 3. 1 19. 7 3550 38,345 49,702
39 91 ,815
52,067 54,652 3. 1 19. 7 3550 41 ,895 48,517
42 94 '180
50, 967 53,510 3.05 18. 9 3409 45,304 47,558
45 96,630
51,707 ft 3 plus 10% = 56.,877 78,100 ft 3 provided to elevation 311.0. Top Berm Elevation -= 311 .2
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DRAINAGE REPORT
for
L.OT lR., BLO.CK 1 .. {24.744 ACRES)
WESTCHESTER PARK -
PHASE ONE
JU_NJOR HIGH SCHOOL
JULY, 1989
OWNED AND DEVELOPED BY:
COLLEGE STATION IND. SCHOOL DISTRICT
1812 WELSH
COLLEGE STATION, TEXAS 77840
PREPARED BY :
KLING ENGINEERING & SURVEYING
4101 TEXAS AVENUE
BRYAN , TEXAS 77803
' ' ' ' ' ' I
I
Drainage Report
for
Lot lR, Block 1, (24.744 Acres)
WESTCHESTER PARK -PHASE ONE
College Stat i on, Texas
July 3, 1989
INTRODUCTION
Lot 1R is the site for the Junior High School. Improvements consist of
40,000 ft 2 lightly loaded sing l e story structure, 125 par ki ng spaces and
associated infrastructure. The site is located on the southeast side of Rock
Prairie Road, approx imately 0.25 miles southwest of Rio Grande Boulevard. The
site is in the Lick Creek drainage basin, near the head waters. In this area,
Rio Grande Boulevard is approximately on the drainage div i de between Lick Creek
basin and Bee Creek basin. This site is considered to be in the secondary
drainage system which i s sens i t i ve to short durat i on , high intensity rainfall
events.
PRE-DEVELOPED CONDITIONS
The 24.744 acre site was divided into a northeast and southwest drainage
area.
NE Drainage
Area
10.7 Acres
L = 1520
Slope= 1.5%
tc -21 min.
Q10 = 19.4 cfs
Storm..vater Flow is to
ditch along Arn0ld Road,
then northeast along Road.
Pre-Developed Total Q ~0 = 41 cfs.
SW Drainage
Area
14.0 Acres
L = 1720
Slope = 1. 1%
t ,.. -29 min.
Q10 = 21 .s cfs
Storrrwater flow is to ditch
along Arnold Road, then north-
east along Road to 2-42" RCP
which discharge in ditch along
Sch af fer Road.
Kling Engineering & Surveying
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The existing soil conditions are as follows:
A thin fine sand which varies in thickness fran 12 to 15 inches.
This sand overlays on Lufkin series c 1 ay which has very s 1 ow i nterna 1
drainage and is susceptible to erosion on slopes greater than 1%.
The vegetation on the site is natural grassland. .,
Jerry Bishop and Associates, Inc., prepared a drainage report dated
September 11, 1984, on Fa~ily Tree Phase I, which later became Westchester
Park Phase I. A 4' wide flat bottan ditch with 4:1 side slopes was
constructed along the comn:::>n line between Westchester Park and the school
site. A review of the Bishop Report indicates the following:
• Design Frequency - 5 yr.
• Ultimate Develop~ent Flow at Os= 110.85 cfs (design) south corner
of school site (i.e. intersection of 4 foot ditch with 3 foot
d i,tch a 1 ong Arnold Road.
• Ultimate Develop:nent Flow at Os = 119. 19 cfs (design) at 2-42" RCP
at intersection of Arnold Road and Schaffer Road.
• Ditch Along Arnold Road -3' bottan with 3:1 side slopes.
• 12.22 Acres (V,W,X,Y) of school site would discharge into
2~42" RCP at intersection of Arnold Road and Schaffer
Road Os = 42 cfs, [using tc = 13 min, this is a time canpatible
to area T.U., see Bishop Report].
Rock Prairie Road is the boundary on the northwest and is a parkway (80
foot right-of-way, 56 foot pavement) which has a crest approximately in the
center of the school site, therefore, no future additional flows can be expected.
The 4 foot bottan earth channel is the boundary on the southwest, this
channel is constructed with 4: 1 side slopes and has._a Os design flow of 110.85
cfs.
1ne 3 foot bottcm earth channel in the right-of-way of Arnold Road is the
boundary on the southeast. This channel is constructed with 3:1 side slopes and
has a Qs design flow of 119. 19 cfs.
The soccer/baseball fields in Southwood Athletic Park are the boundary on
the northeast. Drainage of these fields is northeast or away fran the school
site.
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In sunnary:
• 0 10 Pre-Development for the 24.7 acre school site is 41 cfs.
• This site is near the drainage divide, therefore, no future flows can
be expected across the school site.
• The as-built O/barrel of the existing 42" RCP is 150 cfs/barrel. Total
O = 300 cfs through 2-42" RCP, assLrning E.G.L. equal to pipe slope.
Ex isting velocity 17ft;s.
• Southwest Drainage Area flow through 2-42" RCP with 010 = 21.6 cfs.
Northeast Drainage Area flow to ditch section in Arnold Road then
northeast along Arnold Road O;c = 19.4 cfs.
The O:c flows given are from the school site only and do not include flow
fran Westchester Park.
POST-DEVELOPMENT
The 24. 7 acre school site has been divided into 9 drainage areas. Drainage
Areas I through V being the intense 1 y deve 1 oped portion of the site, with
Drainage Areas VI through VI I I bei ng grass areas.
DRAINAGE AREA I -This area is street and service employee parking and
will drain via 3 - 4 foot wide curb cuts to the existing
4 foot bottan earth channel , This flow wi 11 by-pass the
detention pond. I Q·" = 4.19 cfs ·"
DRAINAGE AREA I I -This area is two tennis courts which drain to a swale
adjoining the northeast property l i ne then to the ditch
in Arnold Road and then northeast along Arnold Road.
This flow will by-pass the detention pond.
I I 010 = 2. 4 cf s
DRAINAGE AREA I I I -This is the southwest half of the school building and
assoc i ated green spaces, walks, and drives. This area
drains via a grate inlet/storm sewer system to the
termination of Drainage Area 111 at the area inlet prior
to the headwa 11 at the detention pond. Pipe sizes range
from 15" to 27" RCP. There are 8 sub-basins within
Drainage Area I I I, each of which have been provided a
gravity overflow path for events greater than the 10 year
and at an elevation below 321.0. The school building
is at 321.0 finish floor, all grass areas adjoining
building begin at 320.5, and have a 1% slope to area
inlets. 111 Q"' = 25.94 cfs
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DRAINAGE AREA IV -This is the northeast half of the school building and
associated green spaces, walks, and drives. This area
i ncludes the bus loop and 91 space parking lot. This
area drains via a grate inlet/storm sewer system to the
termination of Drainage Area IV at area inlet between
the tennis courts and parking lot. Pipe sizes range fran
15" to 27" RCP. There are 11 sub-basins within Drainage
Area IV, each of which have been provided a gravity
overflow path for events greater than the 10 year and
at an elevation below 321.0. IV Q,0 = 28.89 cfs
DRAINAGE AREA V -This area is the two tennis courts and green space which
adjoins · the two tennis courts in Drainage Area I I. This
area wi 11 drain to swale at the beginning of the
detention oond and into the oond. V Q ,~ = 2.66 cfs • . !V
DRAINAGE AREA VI -This area i s the 1.0 acre detention pond and adjoining
grass land. The detention pond has. the fol lowing
characteristics:
• Q,J -73.64 cfs
• Elevation 2-27" RCP which discharge to detention pond
Elevation -310.35
• 0.6% Slope (Bottan Slope) on 8 foyt wide ''v'' Section
low flow invert Q = 20 cfs
• Side Slope -i2:1
• "V" Notch weir control structure flow line elevation
307. 38, Top "V" Elevation -3 iO. 55, Top box El evat fon
-311. 1, Q = 20.5 cfs (release rate)
•Top Embankment -Elevation -311.2
•Discharge pipe 36" RCP at 1.0% slope, L=35, terminate
in face ditch slope in Arnold Road in line with 2-42"
RCP, elevation 307.0
•Top 2-42" RCP, elevation 307. 1 -discharge into
northeast ditch of Schaffer Road
This area wi 11 discharge into the 2-42" RCP at the inter-
sect ion of Arnold Road and Schaffer Road having a slope
of 1.9%, L=45, Q ... 0 ._~, ~~~~c'"'"v = 300 cfs. There are 3 sub-"" \..C.. L..G...;o. l \,..
basins within Drainage Area VI, two of which are small
areas behind the detention pond.
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DRAINAGE AREA VI I -This area is 2.61 acres at the low point of the school
site. It is to be left in its existing condition with
no known future plans, except to be used as a play area.
This area will sheet flow to the ditch in Arnold Road,
then northeast along Arnold Road. This flow will by-
pass the detention pond . VI I 0 10 = 6.76 cfs
DRAINAGE AREA VI I I -This area is 3 .78 acres at the south corner of the
school site, will be used as a spoil area, excess fill
fran building will be placed/carpacted consistent with
future football/track field. This area will sheet flow
to ditch i n Arnold Road, then to 2-42" RCP at Arnold and
Schaffer Road. This flow will by-pass the detention
pond . V I I I o, D = 14 • 7 cf s
DRAINAGE AREA IX -This area is the existing 4 foot bottan with 4:1 side
slope earth channe 1 a long the southwest 1 ine of the
school tract. This flow wi 11 by-pass the detention pond.
The Drainage Areas contributing to the flow through the 2-42" RCP are I,
II, Ill, IV, V, VI, VII, VIII, and IX having a 0 10 = 96.63 cfs.
To account for head loss at i nlets, 0. 10' fall through each i nlet has been
provided.
It is recognized that 15" and 27" RCP are not sta~dard sizes. These sizes
were required by the lack of head available fran finish floor of the 500 foot
long building to the flow line of the 2-42" RCP.
A review of the inflow/outflow sim..ilation will indicate a reauired storage
volume of 351,707 ft 3 design capacity, the provided capacity to el~vation 311 is
78, 100 ft .
The analysis of the 100 year overflow conditions at the detention facility
has assuned all of the embankment will be used as a weir, with a depth of flow
over the embankment of less than 0.5 feet. This overflow will then flow to the
ditch in Arnold Road.
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SUMMARY
• o1o Post-DevelopTient for the 24 .7 acre school site is 105.78 cfs.
• Q ~c to the detention pond is 73.64 cfs.
• o1o which by-pass detent i on pond i s 32. 14 cfs.
• Release Rate ''V'' notch weir is 20.5 cfs.
• 1.0 Acre detention pond will reduce the peak flow Post-Developnent
from 105.8 cfs to 52.6 cfs.
• The existing 2-42" RCP which serve as the outfall structure for rrost
of this project has a Otc:a.' caca.c'ty = 300 cfs . Bishop's Report
ind i cates Q; = 119.2 cfs and this reoort indicates Q•~ = 96.63 cfs from
school site vonly and does not include any flow fr~JWestchester. It
appears that the as-bu i 1 t frequency of the existing 2-42" RCP is between
5 and 10 year s.
• No future flows can be e xpected across this site by virtue of Rock
Prairie Road being on a crest adjoining the school site.
Kling Engineering & Surveying
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FORMULAE
In determining the arrount of storm runoff from the school site, the
Rational Method has been incorporated. This method is expressed by the form..ila:
Q =
where: Q =
c =
=
A =
CIA
discharge, in cfs (cubic feet per second)
runoff coefficient (see page 23 of the College Station
Drainage Policy and Design Standards)
rainfall intensity, in inches per hour (varies with design
frequency and time of concentration, which is the time in
minutes requ i red to drain the farthest region of the drainage
area, see page 27 of the Co 11 ege Stat ion Drainage Po 1 icy and
Design Standards)
drainage area, in acres
For analyzing the f 1 ow through parking lots, swa 1 es and cu 1 v erts, Manning's
fonn.Jla ha s been used. This formula is e xpressed as:
Q = 1. 486 AR 2/3 s 1/2
n
where: Q = discharge, in c fs
A = cross-sectional area of flow, in square feet
R = hydraulic rad iu s
s = slope of the e nergy gradient (usually para 1 lel with the
slope of the channel bottom)
n = Manning . s Roughness Coefficient
For determining the flow through grate inlets, the standard orifice flow
equation has been used:
Q = CA 2gh
where: c -d i scharge of c oefficient 0.6 -
A = area of open ing
g = acceleration due to gravity
h = head water de pth
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For determining the flow through ''V'' notch weir, the fol lowing has been
used:
Q = 2. SH 2 ·5 fan 0/2
where: Q = discharge cf s
H = head or we i r (ft)
0 = angle of notch in degrees
For determining the flow across the detention errbankment , the following
has been used:
' ~ Q = CLH '·_,
where: Q = discharge coefficient
= 3.27 + 0.40 .ti
p
L = effective length of crest
H = head on the crest
p = he i ght of the we i r re.ro k \ , an . ment 1
DRAINAGE W EJ,G~TED
IA.REA _ I c I
I s .w. 0.30
II N.E. 0.30
TOTAL ACRES
Wu;1c~\L S-r1 r<
PAl2 (
--- -----,_ ,_
RUNOFF COMPUTATION
"PRE-DEVELOPMENT"
AREA RUN/ v Tc I Q Qtp Qso QlOO (ACRES) SLOPE 1/ss..c. M l :N,. l 0 1 0
CFS CFS C F S CFS
14 1760/l .05 % 1. 0 29 5 .14 21.6 .... 27 .68 31. 08
10. 7 1520/1.5 % 1. 2 21 6 .05 19. 4 25 .26 27.93
24.7 TOTAL DISCHARGE i 41. 0
~-COREY DRIVE
-----· --·----·--·---···--------· ------
ROCK PRAlRLL·ROAD
--. ·-------·----------.!.-~---------------------· ----------------------
!
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N ORT~E.AST
DRAI NAG E
ARCA
\
\
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\
\
Sovll--i\JJOOD
ATl-\L (Tlt
PA RK
.,-
-----____ ._
RUNOFF COMPUTATION
Page l of 3
"POST-DEVELOPMENT"
DRAINAGE · WE} G~TED AREA RUN/ v Tc I Q >-:0 Q Q
AREA . 'c' (ACRES) SLOPE 1/ssc MIN, 1 0 I O -IP 5 0 I 0 0
CFS CFS CFS CFS
I-A . 0.90 0.11 180/0. 6% l. 7 l . 7 8.63 0.85 0.85 l. l 0 l.22
I-B 0.90 0. 12 185/0. 75 % 2. l 1.5 8.63 0:. 93 0.93 1. 20 1. 33
I-C 0. 90 0. 31 340/l. 6% . 4.5 l. 3 8.63 2.41 2.41 3 .11 3 .43
I I 0. 77 0.36 220/l .8% 4.7 0.8 8.63 2.39 8.69 3.09 3.41
•III-A 0.57 0.37 140/2 % 4.,3 0.5 8.63 l. 82 l.82 2.35 2.59
•III-B 0.34 0.88 120/6 % 4.0 0.5 '8. 63 2. 58 4.4 3.34 3.68
•IIJ-C(l) 0.63 0.62 11 0/ l % 2. l 0.9 8.63 3.37 3.37 4.36 4.80
•III-C(2) 0.22 0.34 100/5.2 % . 4. 0 0.4 8.63 0.64 8. 41 0.83 0.92
•rrr-0(1) 0. 59 0.90 120/0.8% l. 6 1.3 8.63 4.58 4.58 5. 92 6.53
•1 I I - D ( 2 ) 0.22 0.25 100/3 .5% 3.0 0.5 8.63 0.47 13. 46 0.61 0.68
•T TI-E 0.70 0. 50 l 00/2% 4. 3 0.4 8.63 3.02 116. 48 3.90 4. 31
•I I I-F 0. 18 0.63 180/l.7% 1.4 2. l 8.63 0 .98 17.46 l . 26 l. 39
•r r r -G 0.63 l . 5 6 320/0.7 % l. 5 3.6 8.63 8 .48 48.53 10.96 12.09
* Fo r a ll Tc l e ss tha n 10 min utes, use 10 minutes.
• 010 = 73.64 cf s t o de tenti on (16.6 5 Acres, Ca ve = 0. 5 6)
-
RUNOFF COMPUTATION
UPOST-DEVELOPMENTU Page 2 o'f 3
DRAINAGE WE} GrJTED AREA RUN/ v Tc* I Q ~Q Q Q
AREA I c I (ACRES) SLOPE 1/ss.c MIN. I 0 I 0 10 5 Q I 0 0
CFS CFS CFS CFS
• IV-A 0.62 0.61 160/1 % 2. 1 1. 3 8.63 3. 26 3 .26 4 .22 4 .65
• IV-B 0.22 0.35 120/3 % 3.0 0.7 8.63 0.66 3.92 0.86 0. 95 .
• IV-C(l) 0.61 0.62 100/1 % 2 . 1 0.8 8.63 3. 31 3. 31 4 .29 4.73
• IV-C(2) 0.61 0.22 200/0.5 % 1.1 3.0 8.63 1.1 6 8.39 1.50 1.65
• IV-0(1) 0 .60 0.87 120/0.8% 1. 7 1.2 8.63 4 .50 4.50 5.82 6.42
• IV-0(2) 0. 71 0.50 200/0.75 % 1. 6 2 .1 8.63 3.06 15.95 3.96 4.37
• IV-E 0 .65 0. 14 75/2.5 % 5.3 0 .3 8.63 0 .79 16. 74 1. 01 1. 12
• IV-F(l) 0.90 0.51 260/l .4 % 4.0 1.1 8.63 4.00 4.00 5. 12 5. 65
• IV-F(2) 0 .90 0.59 300/2 .0% 5 .7 0 .9 8.63 4.58 4.58 5 . 9(; 6. 53.
• IV-F(3) 0.30 0.89 600/1 .37 % 1.5 6.7 8.63 2.30 10.88 2.98 3.28
• IV-F(4) 0.25 0 .59 180/3.6% 2.3 1.3 8.63 1.27 28 .89 l. 64 1.81
• v 0. 56 0.55 220/l.6 % 3.2 1.1 8.63 2.66 2.66 3.43 3.79
•VI-A 0.45 4 .16 600/3 % 2.0 5.0 8 .63 16. 15 67.34 20.87 23.03
*For all Tc less than 10 minutes, use 10 minutes.
• Q10 = 73.64 cfs to detention (16 .6 5 acres , Cave = 0.56)
·------------------
RUNOFF COMPUTATION
uPosT-DEVELOPMENTu Page 3 of 3
DRAINAGE WE}G~TED AREA RUN/ v Tc* I Q L:O Q Q
AREA 'c' (ACRES) SLOPE 1 /sr::.c MIN .• I 0 I O IP 5 0 I 0 0
CFS CFS CFS CFS
V I-B . 0.45 0. 16 150/2 .5% 2.0 * 8.63 0.6 0.80 0. 89 .
VI-C 0 .45 0. 10 120/0.3 % 2.0 * 8.63 0 ;.4 0.50 0.55
VII 0. 30 2. 61 480/0. 9% . 0.9 8.9 8.63 6.76 8.73 9.63
VII I 0.45 3.78 930/l .0% 2.0 7.7 8.63 14. 7 18. 97 20.92
0.30 1. 21 1130/l . 3 % 2.0 9.4 8.63 3 .1 4. 05 4.46
TOTAL ACRES 25. 41 TOTAL DISCHARGE 105. 78 1 36. 70 150. 81
*For all Tc less than 10 minutes, use 10 minutes.
Drainage Areas I, II, VI-B, VI-C, VII, VIII, IX by-pass detention pond having total 010 = 32.14 cfs.
The release rate of the "V" notch weir is 20.5 cfs.
..... ----.... .. ------......... ._ .....
VOLUME SUPPLIED BY 10 YEAR STORM
CA = 9.32
OUTFLOW
s x MIN = FT 3 17.86 CFS QI 0 FT 3 MIN CA x lzs x 60 MIN
3
6 9. 32 x 10.40 x 60 x 6 = 34,910 6 ,430 : 28,380
9 9.32 x 9. 01 x 60 x 6 45,360 9,644 35. 715
12 9. 32 x 7.98 x 60 x 6 = 53,570 12,860 40,710
15 9.32 x 7. 19 x 60 x 15 60,335 16,074 44 ,261
18 9. 32 x 6.56 x 60 x 15 = 66,060 19 ,290 46, 770
21 9. 32 x 6.05 x 60 x 21 = 71 • 080 2 2, 5 04 48,576
24 9.32 x 5. 62 x 60 x 21 = 75,460 25 , 718 49,742
27 9.32 x 5.25 x 60 x 21 = 79,300 28,933 50,367
30 9.32 x 4.94 x 60 X\30 = 82,910 32,148 50,762*
33 9.32 x 4.66 x 60 x 30 = 86,030 35,363 50,667
36 9.32 x 4.42 x 60 x 30 88,980 38,577 50,403
39 9. 32 x 4.21 x 60 x 30 = 91 ,815 41,792 50, 02 3
42 9.32 x 4. 01 x 60 x 42 = 94; 180 45,007 49,173
45 9, 32 x 3,84 x 60 x 42 = 96,630 48,222 48,408
*Preliminary Volume required 50,762 ft3 plus 10 %.
-- - - - - - - -- - - - -... -c-·-
DETENTION POND ACCUMULATED VOLUMES
At Al, ACCUMULATED
ELEVATION AREA z VOLUME VOLUME
(FTZ) ( FTZ) (FT 3 ) (FT 3 )
307.4 0 0 0 0
308 5 '350 2,675 1'338 1 ,338
308.5 10,400 7,875 3,938 5,276
309 18, 125 14,263 7, 1 31 12,407
309.5 25,000 21,563 10,781 23, 188
31 0 33,925 29 ,463 14,731 37,919
310.5 40,000 36,963 18'481 5 6, 400
311 46,800 43,400 21,700 78, 1 00
TOTAL AVAILABLE STORAGE -78'100 ft 3
Top of Berm Eleva~ion -311 . 2
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DETENTION POND
. INFLOW/OUTFLOW SIMULATION
Page 1 of 2
TIME VIN 6,VIN + V ; v Q v TOTAL v STORE AVG HW OUT OUT STORE
(MIN) (CF) (CF) fCF) (FT) (CFS) (CF)
v
OUT (CF)
0 0
34, 91 0 1 7, 45 5 1.6 3.8 1 368 1368 33,542
6 34, 91 0
43,992 38,767 2.65 13.3 2400 3768 41,592
9 45,360
49 ,802 45,697 2.75 14. 6 ·2631 6399 43,403
12 53,570
50,'.168 50,553 2. 95 17.4 3136 9535 47,032
1 5 60,335
52, 75 7 53,662 3.05 18.9 3409 12; 944 49,348
18 66,060
54,368 55,626 3.1 19. 7 3550 16 ,4 94 50,818
21 71,080
5 5, 1 98 5 6, 776 3 .13 20.2 3637 20,131 51 ,561
2 4 75 ,460
----......
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DETENTION POND !
. I NFLOW/O UTFLOW SIMULATION
Page 2 of 2
VIN 6vlN + V ; v Q v T O TAL v TIME STORE AVG HW OUT OUT STORE
(MIN) (CF) (CF) (CF) (FT) v
(CFS) (CF) OUT (CF)
55,401 57,249 3.15 20.5 3695 23,826 51 , 707
27 79,300
5 5, 31 7 57,279 3. 15 20 .5 3695 27 ,521 51,622
30 82, 91 0
54,742 5 6 '94 9 3. 13 20 .2 3637 31 , 158 51 , 1 05
33 86,030
54,055 56,347 3 .13 20.2 3637 34,795 50,418
...
36 88,980
53,252 55 ·,;602 3. 1 19. 7 3550 38,345 49,702
39 91 ,815
52,067 54,652 3. 1 19. 7 3550 41 ,895 48,517
42 94 '180
50,967 53,510 3.05 18. 9 3409 45,304 47,558
45 96,630
51,707 ft 3 plus 10 % = 56.,877 78,100 ft 3 provided to elevation 311.0. To p Be rm E l e v a ti o n -= 31 l . 2
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DEVELOPMENT PERMIT
PERMIT NO. 0045
FOR AREAS OUTSIDE SPECIAL FLOOD HAZARD AREAS
RE: CHAPTER 13 OF THE COLLEGE STATION CITY CODE
SITE LEGAL DESCRIPTION; LOT 1R, BLOCK 1, WESTCHESTER PARK
PHASE ONE
SITE ADDRESS; 800 ROCK PRAIRIE ROAD
OWNER; COLLEGE STATION ISO
DRAINAGE BASIN
LICK CREEK
TYPE OF DEVELOPMENT:
NEW JR. HIGH SCHOOL
In accordance with Chapter 13 of the Code of Ordinances
of the City of College Station measures shall be taken to
insure that debris from construction, erosion and
sedimentation shall not be deposited in city streets, or
existing drainage facilities.
I hereby grant this permit for development of an area
outside the special flood hazard area. All development
shall be in accordance with the plans and specifications
submitted to and approved by the City Engineer in the
development permit application for the above named project
and all of the codes and ordinances of the City of College
Station that apply.
_7.:::.J.tl:::fl::, _______ _
Date
(
\
Figure XII-1
Application Form
Development Permit
For Areas Outside · Flood Hazard Areas
City of -Col-lege.:~~s,t_ion, Texas ..
· (re: Ordinance No. )
Site Legal .Description: Lot 1 R, Block 1 Westchester Park Phase One
Site Address: Rock Prairie Road
Located in: Watershed
Owner: College Station Ind. School Dis Address: 1812 Welsh College Station
Telephone No.: 764-5400
~~~~~~~~-
Architect/ Address: P. 0. Box 4234 Bryan
Engineer: B.J. Kling, Kling Engineeringelephone No.: 846-6212
~~~~~~~~-
Contractor: N/A Address:
Telephone No.:
Date Application Filed: Approved:
Application is hereby made for the following development:
CSISD Junior High School
Attached as part_of this application:
Application Fee
Drainage Plan with supporting documentation: two copies of each
Other:
ACKNOWLEDGEMENTS:
I, ~D_r_._R_a_y~L~Ch~a~n_c_e_l_l_o_r~~· as owner, hereby acknowledge or affirm that:
The above Drainage Plan and supporting documents complies with the
requirements of -Ordinance No.
Date
98