HomeMy WebLinkAboutStorm Water Drainage Study I ' ' - ---- - - - - -- 1 v - - _
I I , i ,
\ I� I
7 1 ,...... __ I .---- -- .7- -
° y o I I 1 (1 I(...--,
\ 1� b NN
■ A 1 )
m 11 I 1 � I 1 � o
y
w z o g 9 8 , g i �I \. I -__ - -� ,______t 1 ,
A O i m I I / I I , V
m g
2 2 't ' J I 1 1 ?
Im Yee I! S - T$ 1 1 `
' i ' 1 gi , I +
1 \ 1 Ill ;; 1 ^ r! � � - - - -, - ; - -
E i OR � 1 ,, I 1, 1 }. 1 / T I I 1
ij ii� 1r �( ' 1 1 1 �� J I ' � I 1. / $ ! : I '' — - - ' - L - ~'- -' I 1 ' 1 I 1 i
I —r -. —Y — I 1
i3 E8 g i 1 ' ! 1 1_ i ,� �' I l I 4 11,
I I . � •
1 'I 1 I I ��
g _a
i 8 g g 1 I r , 1 � ( � � j! I u i i zg $ 1 1 1 it I `� I i \ I) jam` i .....,
-r 1 11 1 1 1 1 I -- --
i
I 8 ys$ 1 1 1 I' 1 n
X I 1 I I� I 1 \I V i 1
r A i i G "' -' 14 1, 1 1 1 1 ) I a I I
m m a �, o ;. 1 II I
1 I ( I
— 4 1
/ I� -
, , I, v r , II ' 1 , �
I/ '0 1 I 1 1 I . � c' J' 1 - --
I� I /,III --�- ',r'
11 /' 1
I �♦ / ``�__ —_ ( 1
1 1 • , J I 1 \ I I
,J _ I \ 11
1 }
1 I i i I r— -- I `` ` r
I
1
7 I J I ' n\J I I I ( '
I I 1 ` I 1 (
I I� 1 '
I I
1 \ ----- r„ ili \
0
°z A A. I I I I �; I
,, m n° 1 i/ n / �� / 1 _ _ l
a
'
o III � l 1 m � ( 1 �� I
I I I
I I r / I /. \\ N.,_ I
r
11! / l ' I I 1 I I
° ° Emy 11 I 1 1 / r
�� "$ I (aaWL751 ur NU!
—
0
oopm o I - l\ ( I �
N I I
L
\ - i
° / H_____[__
.... "--- 7 , -...-
y o m \�- .c.--T _ 1 I / .
rn$ i I I \ \ �_
P 1 1 T M 1 I % ����
H m I / 1 - -- .. -- +,
/
y 1 1 / 1 1 \ / \` /
/ o f /
3p - II i - /J �` 1 - \\ i
° 1 1 1 I 1 - / 1 (
r1�9m 11 � 1 /"' -� �\ ^ ,� -- \�-\ \`
Ii m inx= I I '
°y`� —14141 I flit I \ _ _ _) 7C N- - - - --' ��\ 1 �
/
.. ...
1 ; li I
1 / , /
F1
n [>>>>>> ° N STEPPING STONE SCHOOL °
�, �" a a � � � .O p ooA
2 O F " tr IZ N ° , .. rO min
c) 8 m Z m cn o m m V “
D ° _ " 205 ROCK PRAIRIE ROAD ilT: 'gib' g � I
C )w, � 3
Cv m COLLEGE STATION, TEXAS z ` ' '' 0 v ° 0
e -4 I
• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
_--,1 N I 1
1 J 11� l
v H ' ' g 1AJ r'r8 I \ 1 o a ] 1 I \ I 11 I
3 I \ 1 I U I � (yg 1 8 m $ 8 ) I V I \� � // / m 1 i i . ) 1 t >�" � g gH P u I 1 \ 3 'F i g 4 � \ 1 N I F li
&!e1 = I. 8 8i t tai \ ' / n 1 I ( r _ 1- - -- -- C ) I 1
k i k 1 111 1 \ I I 1 1 � i ( \— / z--.., l /
1 I \ // 1 I 1 I i ' \ ) ti.
1 l i I V � p � I I l am, // \ \ I) / 1 )
n o _ I 1 ; 1 III1 '( --- - -�I
p pp
mR i AlE I I 1� II° 1 I _.. ... / < 11
I I 1 II
c 1 e 5 = ' 3 ' d ' d I
P . AS SSS'S /
8 n, 8 I I ' 100HOS o3SOdOHd . ■ / I
I
sr8 17 m \ \, / m A s�€ \ 1 1 I ! ;� 1 � n
k 1 1 \ I I I ;1;, l i / L — _ _ —
i I I II �I ` I II ! 1 ` C\ 1 I \ I i
I � � , - 1 \\ 1
Ell �l E m i t i \ I I III 1 D - - -- 1 /
'� $ - � 1 I I I!1 I V U 1
1 j I
1 g I i I i I I i V \_ - -� I -- ' -- II
en S.' Ii2tOt 1 i .N--J / I 1 I � I /I\ �� II
e \ / ,/ I / \ I ��I 1 `
c y R � .o � y i I I f / I I I
-i9 7 --,----„7,-----4
m
1 e I I 7 (—)
' ; m�oo3m I o ( i J �+I 1
I i °-" 1 I I D 1 I 1 I 1 1
A € _ ® `� 1 I I 1 I
w I I I 1
— t H
Eo 3 o I I I I
s 1 -1 A I 1
n 1 1
m go'om 1 1 I I 1 .
2° op &I I 1 1 ( `
fs �; 1 I \ 1 1 � - -- I
I
4 1,I I 11 j
QS
,yp I I I II, \ � 1
IL iff Q o 1 \.
DDD — I I
y I 1 11 / I 1
t 1 1 1 / I
I i I -- — (\ ) I F
1 I I --� - -- -- —F ( I
I i I / 1 l I 1 l I moo.. \
I /
1 1 l �
1 I I I 0, I
I I
''1' 1 I / (
‘-‘1:1.> , $ 1 i I I I ( / l
;O� =" I 1...... y / / / I
i ° r�mr I a O \ ° my i D I / �� / / SAN I I _/
o�o _ _
g�r� Z p A g o v c - - - - - 1 EDELWEISS AI�ENUE J ,�
ogg y m o 0
m
s _ _
2 n _ _ _ ,._,....,. ,,
l Ns 2 A y C I r .... \\ .
2 \
!, z \ J I I I I
° = o 2 II 1 / I 11 I 1 /
= m 1 ; ) /
l
ii I
/ \ t \ I 1 1 /
Sn. ;p I 1 II \� ( \ \ \, 1..._x
\\ 1
....
71,-..... 4
,,, In g. ` I 1 1 I / /
■
II I ` � L - -- - -`� ( (- \ - / t •--- ' - • ■
o
m
m
o N i c °'' _ STEPPING STONE SCHOOL :ti.,,,: s r , p g g
(71 t 205 ROCK PRAIRIE ROAD A 2fri ;g =
COLLEGE STATION, TEXAS , ,, `'� ' v � ��
rt,
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• Storm Water Drainage Study
• Stepping Stone School
• College Station, Texas
•
•
•
•
•
•
•
• 0 Gessner Engineering
•
•
•
•
• 2
•
•
• August 22, 2011
•
• Mr. Josh Norton
• City of College Station Planning Services
• 1101 Texas Avenue
• College Station, TX 77842
• Re: Storm Water Drainage Study
• Stepping Stone School
• College Station, Texas
• Gessner Engineering Job No.: 11 -0152
• Dear Mr. Norton:
• This report conveys the results of the storm water drainage study conducted by Gessner
• Engineering for the proposed Stepping Stone School in College Station, Texas. Gessner
• Engineering believes that all information contained in this report is valid. Please contact us
• if you have any questions or if we can be of further assistance.
• "This report for the drainage design of the Stepping Stone School was prepared by me in
• accordance with provisions of the Bryan /College Station Unified Drainage Design
• Guidelines for the owners of the property. All licenses and permits required by any and all
• state and federal regulatory agencies for the proposed drainage improvements have been
issued."
•
• Sincerely,
• GESSNE' . NGI ERING 4 .000.10 1 „�
• • Apo _ _ __ _ (:1 �
• Jeri r eters, P.E., C.F.M. JERE ,, PETER
1
• : 00217 .•' . � 5
• t F� ••........• � e 4t
• Kyle M. Zapalac, M.E., E.I.T. ‘11,, ut.es:
•
•
•
•
•
•
•
• N: \Gessner Eng Data 11 \11 -0152 Stepping Stone School \Civil\DOC \11 -0152 Drainage Report - NRCS.doc
• G Gessner Engineering
•
•
•
•
• 3
•
•
• Executive Summary
• This storm water drainage report is submitted to the City of College Station, Texas for
• review on August 22, 2011 by Jeremy N. Peters, P.E., C.F.M. of Gessner Engineering,
located at 2501 Ashford Drive, Suite 102, College Station, Texas 77840. This report is
•
submitted on behalf of Mr. Daniel Turner of Stepping Stone School at 1910 Justin Lane,
• Austin, Texas 78757.
• The proposed project consists of construction of a 5,968 square foot school building with
• associated parking and infrastructure on an approximately 0.607 acre site. The site is
• currently vacant.
• The site is located near the northeast corner of the intersection of Wellborn and Rock
• Prairie Road at 205 Rock Prairie Road in College Station, Texas. It is located in the
• northwest corner of the Lick Creek Watershed near the border of the Bee Creek
• Watershed. The site is not located in the FEMA 100 year flood plain, according to FIRM
• number 48041 C0182C.
• Under Section I1.3.b.(3) of the Bryan /College Station Unified Stormwater Design
• Guidelines, this site is not required to provide detention as a small commercial lot, less than
• one (1) acre. However, detention is proposed for the site, and Gessner Engineering
• believes the minimal increase in pre - developed flows will have a negligible impact on
downstream conditions. The proposed site provides for the stormwater runoff to follow the
• existing drainage patterns. The northwest third of the proposed development will be
• released to the north. This area drains toward the existing Edelweiss Subdivision under
• existing conditions. The remainder of the property will drain to Rock Prairie, which matches
the direction of flow under existing conditions. This runoff will also be detained prior to
• release. However, this runoff will not be detained to existing flow values.
• Due to the size of development at this site, a Notice of Intent is not required for submittal to
• the Texas Commission on Environmental Quality.
•
• This drainage report includes discussion of hydrologic and hydraulic analysis with
• appendices including drainage area maps, calculations, and Technical Design Summary.
•
•
•
•
•
•
•
•
•
• N: \Gessner Eng Data 11 \11 -0152 Stepping Stone School \Civil\DOC \11 -0152 Drainage Report - NRCS.doc
• G
• Gessner Engineering
•
•
•
• 4
•
•
• Introduction
•
• This stormwater drainage report is intended to show the change in runoff from the existing
conditions to the proposed conditions for the Stepping Stone School. The general flow of
• the site is depicted by directional flow areas on sheet C -05 A of the Civil Engineering Plans
• for Stepping Stone School, which is attached as Appendix A.
• Drainage Calculations for this site were prepared according to the Natural Resources
• Conservation Service method as detailed in Technical Release 55 (TR -55) published in
• June of 1986. The proposed construction includes an approximately 5,968 square foot
• building with a parking lot. Curve numbers from TR -55 were used based on post-
• developed uses as described above. Pre - developed flows were calculated based on the
existing conditions on the subject tract. The calculated pre - developed and post - developed
• flows for the site include the one - hundred (100) year storms in accordance with the
• Bryan /College Station Unified Stormwater Design Guidelines.
•
While the proposed site and the overall drainage area are less than 50 acres, the NRCS
• was used because the drainage area contributed to public infrastructure and other drainage
• areas. While Rational Method would be acceptable for this drainage area, the NRCS
• method would allow for more comprehensive analysis with other contributing drainage
• areas.
• Using the exemption provided under the Bryan /College Station Unified Stormwater Design
• Guidelines, the proposed development does not detain to pre - developed runoff rates. The
• analysis for this lot is based on the larger drainage area contributing to the west curb inlet
located on Edelweiss Avenue at the intersection of Rock Prairie Road.
•
• Calculations
•
• Calculations were performed according to the NRCS TR -55 and with the aid of HEC -HMS,
version 3.5 by the U.S. Army Corps of Engineers. The output data from HEC -HMS has
• been provided as Appendices B, C, and D.
•
•
•
•
•
•
•
•
•
•
• N: \Gessner Eng Data 11 \11 -0152 Stepping Stone School \Civil\DOC \11 -0152 Drainage Report - NRCS.doc
• 0 Gessner Engineering
•
•
•
•
• 5
•
•
• Time of Concentration
• The time of concentration (travel time) for each drainage area was estimated by summing
• the flow time for each segment of travel. For sheet flow, travel time was estimated by
Manning's Kinematic equation:
•
• 0.007 x (nL)
t _
• r s0. V p25
•
• Where:
• tt = travel time (hours)
n _ manning's roughness coefficient
•
L flow length (feet)
• S = slope (ft/ft)
• P25 = 25 -year, 24 hour rainfall (inches)
• For shallow concentrated flow, the travel time was calculated from the flow velocity based
• on the slope in the direction of flow. These velocities were taken from Table C -4 of the
• Bryan /College Station Unified Stormwater Design Guidelines.
• The computed times of concentration for each drainage area are included on sheets C -05
• A and C -05 B of Appendix A. Computed values were increased to a minimum time of ten
• (1 0) minutes as required.
• Unit Hydrograph
• A generic unit hydrograph was computed by distributing the rainfall depths (Table One)
• according to the distribution factors for the NCRS Type III 24 hour storm. This hydrograph
• was then applied to each subarea based on the curve number and time of concentration of
• that area.
• Reach Routing
• Hydrographs were routed from subareas to the outflow through the kinematic wave
• method. This method allows for hydrographs to be translated with time but not attenuated.
• Peak Runoff Flow
• Peak Runoff Flow from the site was determined based on the Type III 24 hour storm
• applied to each drainage area. The depth- duration - intervals for each frequency are
included in Table One below, and were pulled from Table C -6 in the Bryan /College Station
• Unified Stormwater Design Guidelines. Curve Number values (CN) were determined from
• Table C -7, Appendix C of the Bryan /College Station Unified Stormwater Design Guidelines.
• Peak pre - developed flows for the subject site are also included in Table One. These
values are based on a combined hydrograph for the flow from each drainage area.
• Drainage areas and calculations are included on sheet C -05 A, attached as Appendix A.
•
•
• N: \Gessner Eng Data 11 \11 -0152 Stepping Stone School \Civil\DOC \11 -0152 Drainage Report - NRCS.doc
• 0 Gessner Engineering
•
•
•
•
• 6
•
•
• Table One shows the peak flows at each storm event at the curb inlet located at Edelweiss
• Avenue and Rock Prairie Road.
• Rainfall Depth (in), Pre - Developed Peak
• Frequency 24 -hr duration Flow at Curb Inlet (cfs)
• 100 years 11.00 45.6
50 years 9.80 40.3
• 25 years 8.40 34.2
• 10 years 7.40 29.7
• 5 years 6.20 24.4
2 years 4.50 16.8
• Table One: Rainfall Depths and Resulting Flows
• The post - developed flows were analyzed based on the drainage areas shown on the
• attached sheet C -05 B. The resulting flow based on the increased curve numbers at the
• site is shown in Table Two below. The increase from the pre - developed flow is also
• included.
• Pre - Developed Peak Post - Developed Peak
• Storm Event Flow at Curb Inlet (cfs) Flow at Curb Inlet (cfs) Flow Increase (cfs)
100 years 45.6 46.4 0.8
• 50 years 40.3 41.1 0.8
• 25 years 34.2 34.9 0.7
10 years 29.7 30.5 0.8
• 5 years 24.4 25.2 0.8
• 2 years 16.8 17.5 0.7
Table Two: Pre - Developed and Post- Developed Site Outflows
•
• The peak flow increase reflected in Table Two for each storm event are the result of the
• proposed development and maximizing surface detention in the two detention ponds.
• Additionally, the pre- and post - developed flows in the gutter of Rock Prairie were analyzed
• to ensure that the increased post - developed flows do not have an adverse impact. Table
• Three shows the pre- and post- developed gutter flow on Rock Prairie for the 25 year storm
• event, along with spread of that flow. Calculations for the gutter flow can be found in
Appendix E.
•
• Pre- Developed Pre - Developed Spread Post - Developed Post - Developed Spread
Storm Event Peak Flow (cfs) at Peak Flow (ft.) Peak Flow (cfs)_ at Peak Flow (ft.)
• 25 years 27.2 22.07 28.1 22.41
• Table Three: Pre - Developed and Post - Developed Rock Prairie Gutter Flow
•
•
•
•
•
• N: \Gessner Eng Data 11 \11 -0152 Stepping Stone School \Civil\DOC \11 -0152 Drainage Report - NRCS.doc
• 0 Gessner Engineering
•
•
•
•
• 7
•
•
• Conclusion
•
• Based on visual evidence, engineering drainage calculations and sound engineering
• judgment, Gessner Engineering believes that the increase from the pre - developed flow to
the post - development flows is minimal for the 100 year design storms for this site.
•
• Based on Section II.3.b.(3) of the Bryan College Station Unified Stormwater Design
• Guidelines, detention is not required for this "small lot ", defined as "equal or less than one
(1) acre for commercial use." Additionally, the minimal increase in flow of 1.1 cfs at the 100
• year storm event will have a negligible impact on downstream conditions.
•
• "I have conducted a topographic review and field investigation of existing and proposed
• flow patterns for stormwater runoff from the Stepping Stone School development to Rock
Prairie Drive and the adjacent properties. At build -out conditions allowable by zoning,
• restrictive covenant, or plat note, the stormwater flows from the subject subdivision or site
• project will not cause any increase in flooding conditions to the interior of existing building
• structures, including basement areas, for storms of magnitude up through the 100 -year
event. ":
•
•
• �1 EOF . t E
f .• C 1 • • � 40
• '�
FNSE.••'
• , �` `"`N i
•
•
•
•
•
•
•
•
•
•
•
•
•
• N: \Gessner Eng Data 11 \11 -0152 Stepping Stone School \Civil\DOC \11 -0152 Drainage Report - NRCS.doc
• 0 Gessner Engineering
•
•
•
•
• 8
•
•
•
•
•
•
•
•
•
•
•
•
•
• APPENDIX A:
•
• Drainage Area Maps and Calculations
• (Sheet C -05 A & C -05 B)
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• N: \Gessner Eng Data 11 \1 1 -0152 Stepping Stone School \Civil\DOC \11 -0152 Drainage Report - NRCS.do
• 0 Gessner Engineering
•
•
•
•
• 9
•
•
•
•
•
•
•
•
•
•
•
•
• APPENDIX B:
• Hydrographs
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• N: \Gessner Eng Data 11 \11 -0152 Stepping Stone School \Civil\DOC \11 -0152 Drainage Report - NRCS.doc
• 0 Gessner Engineering
•
•
■
•
•
•
• Junction "CURB INLET" Results for Run "100 YR POST DEVELOPED"
• 50
•
•
F
• 45
•
•
• 40
•
• 35 i
• I €
•
• 30 C
I
• I
III
• 25
• o
20 I
•
•
• 15
•
•
•
I
__._ Ji '
5_ —
•
•
• 00:00 12:00 00:00 12:00 00:00
• I 22Jun2011 1 23Jun2011
•
• - Run:100 YR POST DEVELOPED Element:CURB INLET Result:Outflow — — — Run:100 YR POST DEVELOPED Element:JCT DA1 Result:Outflow
• Run:100 YR POST DEVELOPED Element:JCT DA2 Result:Outflow
•
•
•
•
e
•
•
•
• Junction "CURB INLET" Results for Run "50 YR POST DEVELOPED"
• 45
•
•
40
•
•
•
35
•
• I
• 30
1
•
•
• 25
•
N
• U
• 3
2 20
u.
•
•
• 15_
•
•
•
10
•
•
•
• f ,
• 1
• _____„_ \''"----:—.,___ : .
• 0 1 1 1 1
• 00:00 12:00 00:00 12:00 00:00
22Jun2011 I 23Jun2011
•
•
• — Run:50 YR POST DEVELOPED Element:CURB INLET Result:Outflow — — — Run:50 YR POST DEVELOPED Element:JCT DA1 Result:Outflow
• Run:50 YR POST DEVELOPED Element:JCT DA2 Result:Outflow
•
•
•
•
•
•
•
•
• Junction "CURB INLET' Results for Run "25 YR POST DEVELOPED"
• 40
•
•
•
• 35
•
•
30
•
•
i
•
t
• 25_ _
•
•
• '
• u 20 l
•
.,
'
0
•
• 15- I_
•
•
•
•
• f
i
• ti
5- r __
•
•
• • 0 i
• 00:00 12:00 00:00 12:00 00:00
• I 22Jun2011 1 23Jun2011
•
• - Run:25 YR POST DEVELOPED Element:CURB INLET Result:Outflow — — — Run:25 YR POST DEVELOPED Element:JCT DA1 Result:Outfow
•
Run:25 YR POST DEVELOPED Element:JCT DA2 Result:Outflow
•
•
•
•
•
•
•
•
• Junction "CURB INLET" Results for Run "10 YR POST DEVELOPED"
• 35
•
• ! E
• r
t
• �_.�, E
30- ..__.
•
•
•
• 1
•
• E
•
• 20 I t
• w
• 1 `
L
•
•
•
•
•
• '
• j
1
• '
7
E
•
• I
i
• 0 1 1 1 1
• 00:00 12:00 00:00 12:00 00:00
• I 22Jun2011 1 23Jun2011
• - Run:10 YR POST DEVELOPED Element:CURB INLET Result:Outflow — — — Run:10 YR POST DEVELOPED Element:JCT DA1 Result:Outflow
• Run:10 YR POST DEVELOPED Element:JCT DA2 Result:Outflow
•
•
•
•
•
•
•
•
•
• Junction "CURB INLET" Results for Run "5 YR POST DEVELOPED"
• 30
•
•
•
I
•
.
•
• '
•
•
•
• 20
•
•
•
•
•
u 15_
• 3
lL
•
•
I
• 10_ I_
• !
•
•
•
• 5
•
E
• � '
•
•
• 0 1 -----P'Q'll 1 i '
• 00:00 12:00 00:00 12:00 00:00
• I 22Jun2011 1 23Jun2011
•
• - Run:5 YR POST DEVELOPED Element:CURB INLET Result:Outflow — — — Run:5 YR POST DEVELOPED Element:JCT DA1 Result:Outflow
• Run:5 YR POST DEVELOPED Element:JCT DA2 Result:Outflow
•
•
•
•
5
•
•
•
• Junction "CURB INLET" Results for Run "2 YR POST DEVELOPED"
•
18
•
• I
• 16
•
•
• 14
•
• 12-
•
•
• 10
•
N
• -
• 6 _
•
•
6
• I
'•
• 4 _
•
•
• 2 - ) ' ' . .
•
• ..,j , 111111111huisomi...: :
• 00:00 12:00 00:00 12:00 00:00
• 1 22Jun2011 1 23Jun2011
•
• — Run:2 YR POST DEVELOPED Element:CURB INLET Result:Outflow — — — Run:2 YR POST DEVELOPED Element:JCT DA1 Result:Outflow
• Run:2 YR POST DEVELOPED Element:JCT DA2 Result:Outflow
•
•
•
•
•
•
•
•
• Junction "CURB INLET" Results for Run "100 YR PRE DEVELOPED"
• 50
• '
•
• 45- w. __. 1
•
•
• 40
•
•
• 35
•
•
• 30_
• I
I
•
U 25 _
I
•
• o
u.
•
• 20
•
•
15
•
•
•
10
•
• I
• 5
•
1
• _
• 00:00 12:00 00:00 12:00 00:00
• I 22Jun2011 1 23Jun2011
•
• — Run:100 YR PRE DEVELOPED Element:CURB INLET Result:Outflow — — — Run:100 YR PRE DEVELOPED Element:DA1 Result:Outtlow
• Run:100 YR PRE DEVELOPED Element:JCT DA2 Result:Outflow
•
•
•
•
w
•
•
•
• Junction "CURB INLET" Results for Run "50 YR PRE DEVELOPED"
•
45
•
•
•
40
•
• 1
•
• 1 i
3 _
•
• I k
• 25
• N 4.
• v
20
u.
•
•
• l
15
•
•
10
•
•
i
•
i
1
•
•
•
• 0 ,
• 00:00 12:00 00:00 12:00 00:00
22Jun2011 1 23Jun2011
•
•
• — Run:50 YR PRE DEVELOPED Element:CURB INLET Result:Outflow — — — Run:50 YR PRE DEVELOPED Element:DA1 Result:Outflow
• Run:50 YR PRE DEVELOPED Element:JCT DA2 Result:Outflow
•
•
•
•
■
•
•
•
• Junction "CURB INLET" Results for Run "25 YR PRE DEVELOPED"
• 35
•
•
30
•
•
•
25
• l
•
•
20
•
• N
• U
• 3
• u. 15- I __
•
•
•
•
•
•
i
•
) L.,....,_____i' ,
•
•
• 00:00 12:00 00:00 12:00 00:00
• I 22Jun2011 1 23Jun2011
•
• — Run:25 YR PRE DEVELOPED Element:CURB INLET Result:Outflow - -- Run:25 YR PRE DEVELOPED Element:DA1 Result:Outflow
• Run:25 YR PRE DEVELOPED Element:JCT DA2 Result:Outflow
•
•
•
•
•
•
•
•
• Junction "CURB INLET" Results for Run "10 YR PRE DEVELOPED"
• 35
•
• 1
•
•
30
•
25_ 3
•
•
•
20
•
• N
3 '
• O
II 15_ --
• 1
• I E
•
•
•
• 5-
• '
i
•
•
• 01 1 i 1
•
00:00 12:00 00:00 12:00 00:00
• I 22Jun2011 I 23Jun2011
•
• — Run:10 YR PRE DEVELOPED Element:CURB INLET Result:Outflow — — — Run:10 YR PRE DEVELOPED Element:DA1 Result:Outflow
•
Run:10 YR PRE DEVELOPED Element:JCT DA2 Result:Outflow
•
•
•
•
•
•
•
•
• Junction "CURB INLET" Results for Run "5 YR PRE DEVELOPED"
•
25- ,
•
•
•
•
•
• 20 :__
• f
•
• I
•
•
15_
•
N
• U
• g
LI
1
• 10- �.._. _ ..
•
•
•
•
•
•
3
i
•
•
J-----) 1 1 i
•
• 1
• 01
• 00:00 12:00 00:00 12:00 00:00
• 1 22Jun2011 I 23Jun2011
•
• - Run:5 YR PRE DEVELOPED Element:CURB INLET Result:Oufflow — — — Run:5 YR PRE DEVELOPED Element:DA1 Result:Outflow
• Run:5 YR PRE DEVELOPED Element:JCT DA2 Result:Outflow
•
•
•
•
•
•
•
•
• Junction "CURB INLET' Results for Run "2 YR PRE DEVELOPED"
• 18
•
• '
• '
16 - _.
• ,
• I
•
i
•
•
i I
• 12
•
•
• 10-
• N
• U
• 0
u_ f
• 1
•
•
•
•
• 4 _
•
•
3
,
• 1
i
• [
•
j., 1
E i
• 0 I 1 1 1
• 00:00 12:00 00:00 12:00 00:00
• I 22Jun2011 1 23Jun2011
•
• — Run:2 YR PRE DEVELOPED Element:CURB INLET Result:Outfow — — — Run:2 YR PRE DEVELOPED Element:DA1 Result:Outflow
• Run:2 YR PRE DEVELOPED Element:JCT DA2 Result:Outflow
•
•
•
•
•
•
• 10
•
•
•
•
•
•
•
•
•
•
•
• APPENDIX C:
•
• HEC -HMS Calculations
• (Pre - Developed Conditions)
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• N: \Gessner Eng Data 11 \11 -0152 Stepping Stone School \Civil\DOC \11 -0152 Drainage Report - NRCS.doc
• Gessner Engineering
•
•
•
•
•
•
•
•
Project : 11 -0152 - Revised
• Basin Model : PRE DEVELOPED
• HEC -HMS Aug 17 08:05:13 CDT 2011
•
•
• ` DA2
•
• JCT DA2
•
• '` SITE DA2
•
• CURB INLET
•
SITE DA3
•
• DA1
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• Project: 11 -0152 - Revised Simulation Run: 100 YR PRE DEVELOPED
•
• Start of Run: 22Jun2011, 00:00 Basin Model: PRE DEVELOPED
• End of Run: 24Jun2011, 00:00 Meteorologic Model: 100YR
• Compute Time: 16Aug2011, 13:30:37 Control Specifications: Control 1
• Hydrologic Drainage Area Peak DischargeTime of Peak Volume
• Element (MI2) (CFS) (AC -FT)
• DA1 0.0063000 36.1 22Jun2011, 12:07 3.4
• DA2 0.0027000 10.9 22Jun2011, 12:18 1.3
• SITE DA2 .0003 1.6 22Jun2011, 12:07 0.1
• JCT DA2 0.0030000 11.8 22Jun2011, 12:17 1.5
• CURB INLET 0.0093000 45.6 22Jun2011, 12:08 4.8
• SITE DA3 .00005156 0.3 22Jun2011, 12:07 0.0
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• Project: 11 -0152 - Revised Simulation Run: 50 YR PRE DEVELOPED
•
• Start of Run: 22Jun2011, 00:00 Basin Model: PRE DEVELOPED
• End of Run: 24Jun2011, 00:00 Meteorologic Model: 50YR
• Compute Time: 16Aug2011, 13:31:16 Control Specifications: Control 1
• Hydrologic Drainage Area Peak DischargeTime of Peak Volume
• Element (MI2) (CFS) (AC -FT)
• DA1 0.0063000 32.0 22Jun2011, 12:07 3.0
• DA2 0.0027000 9.6 22Jun2011, 12:18 1.2
• SITE DA2 .0003 1.4 22Jun2011, 12:07 0.1
• JCT DA2 0.0030000 10.4 22Jun2011, 12:17 1.3
• CURB INLET 0.0093000 40.3 22Jun2011, 12:08 4.3
• SITE DA3 .00005156 0.2 22Jun2011, 12:07 0.0
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Project: 11 -0152 - Revised Simulation Run: 25 YR PRE DEVELOPED
•
• Start of Run: 22Jun2011, 00:00 Basin Model: PRE DEVELOPED
• End of Run: 24Jun2011, 00:00 Meteorologic Model: 25YR
• Compute Time: 16Aug2011, 13:30:59 Control Specifications: Control 1
• Hydrologic Drainage Area Peak DischargieTime of Peak Volume
• Element (M12) (CFS) (AC -FT)
• DA1 0.0063000 27.2 22Jun2011, 12:07 2.5
• DA2 0.0027000 8.1 22Jun2011, 12:18 1.0
• SITE DA2 .0003 1.2 22Jun2011, 12:07 0.1
• JCT DA2 0.0030000 8.7 22Jun2011, 12:17 1.1
• CURB INLET 0.0093000 34.2 22Jun2011, 12:08 3.6
• SITE DA3 .00005156 0.2 22Jun2011, 12:07 0.0
•
•
•
•
•
•
•
•
•
9
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• Project: 11 -0152 - Revised Simulation Run: 10 YR PRE DEVELOPED
•
• Start of Run: 22Jun2011, 00:00 Basin Model: PRE DEVELOPED
• End of Run: 24Jun2011, 00:00 Meteorologic Model: 10YR
• Compute Time: 16Aug2011, 13:30:50 Control Specifications: Control 1
• Hydrologic Drainage Area Peak DischargieTime of Peak Volume
• Element (M12) (CFS) (AC -FT)
• DA1 0.0063000 23.7 22Jun2011, 12:07 2.2
• DA2 0.0027000 7.0 22Jun2011, 12:18 0.8
• SITE DA2 .0003 1.0 22Jun2011, 12:07 0.1
• JCT DA2 0.0030000 7.6 22Jun2011, 12:17 0.9
• CURB INLET 0.0093000 29.7 22Jun2011, 12:08 3.1
• SITE DA3 .00005156 0.2 22Jun2011, 12:07 0.0
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Project: 11 -0152 - Revised Simulation Run: 5 YR PRE DEVELOPED
•
• Start of Run: 22Jun2011, 00:00 Basin Model: PRE DEVELOPED
• End of Run: 24Jun2011, 00:00 Meteorologic Model: 5YR
• Compute Time: 16Aug2011, 13:31:34 Control Specifications: Control 1
• Hydrologic Drainage Area Peak DischargeTime of Peak Volume
• Element (MI2) (CFS) (AC -FT)
• DA1 0.0063000 19.6 22Jun2011, 12:07 1.8
DA2 0.0027000 5.6 22Jun2011, 12:18 0.7
SITE DA2 .0003 0.8 22Jun2011, 12:08 0.1
• JCT DA2 0.0030000 6.1 22Jun2011, 12:17 0.7
• CURB INLET 0.0093000 24.4 22Jun2011, 12:08 2.5
• SITE DA3 .00005156 0.1 22Jun2011, 12:08 0.0
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
l�
•
•
•
•
• Project: 11 -0152 - Revised Simulation Run: 2 YR PRE DEVELOPED
•
• Start of Run: 22Jun2011, 00:00 Basin Model: PRE DEVELOPED
• End of Run: 24Jun2011, 00:00 Meteorologic Model: 2YR
• Compute Time: 16Aug2011, 13:31:07 Control Specifications: Control 1
• Hydrologic Drainage Area Peak DischargieTime of Peak Volume
• Element (M12) (CFS) (AC -FT)
• DA1 0.0063000 13.6 22Jun2011, 12:07 1.2
• DA2 0.0027000 3.8 22Jun2011, 12:18 0.4
• SITE DA2 .0003 0.5 22Jun2011, 12:08 0.0
• JCT DA2 0.0030000 4.1 22Jun2011, 12:18 0.5
• CURB INLET 0.0093000 16.8 22Jun2011, 12:08 1.7
• SITE DA3 .00005156 0.1 22Jun2011, 12:08 0.0
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• 11
i •
•
•
•
•
•
•
•
•
•
•
• APPENDIX D:
•
• HEC -HMS Calculations
• (Post - Developed Conditions)
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• N: \Gessner Eng Data 11 \11 -0152 Stepping Stone School \Civil\DOC \11 -0152 Drainage Report - NRCS.doc
• 0 Gessner Engineering
•
•
•
•
•
•
•
z Project : 11 -0152 - Revised
• Basin Model : POST DEVELOPED
• HEC -HMS Aug 17 08:05:05 CDT 2011
•
•
• _ DA2
•
• :` JCT DA2
•
ITE DA2
•
•
CURB INLET
• tor44, SITE DA3
•
•
• JCTDA1
• _ SITE DA1
•
• POND /PARKING LOT
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• Project: 11 -0152 - Revised Simulation Run: 100 YR POST DEVELOPED
• Start of Run: 22Jun2011, 00:00 Basin Model: POST DEVELOPED
• End of Run: 24Jun2011, 00:00 Meteorologic Model: 100YR
• Compute Time: 17Aug2011, 08:01:05 Control Specifications: Control 1
• Hydrologic Drainage Area Peak DischargeTime of Peak Volume
• Element (MI2) (CFS) (AC -FT)
• DA1 0.00580 33.3 22Jun2011, 12:07 3.1
• SITE DA1 0.00070 4.1 22Jun2011, 12:07 0.4
• POND /PARKING LOT 0.00070 3.9 22Jun2011, 12:10 0.4
• JCT DA1 0.00650 37.0 22Jun2011, 12:07 3.5
• DA2 0.00270 11.0 22Jun2011, 12:17 1.3
• SITE DA2 0.00020 1.1 22Jun2011, 12:07 0.1
JCT DA2 0.00290 11.7 22Jun2011, 12:17 1.5
• CURB INLET 0.00940 46.4 22Jun2011, 12:08 5.0
• SITE DA3 0.00004 0.2 22Jun2011, 12:07 0.0
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• Project: 11 -0152 - Revised Simulation Run: 50 YR POST DEVELOPED
•
• Start of Run: 22Jun2011, 00:00 Basin Model: POST DEVELOPED
• End of Run: 24Jun2011, 00:00 Meteorologic Model: 50YR
• Compute Time: 17Aug2011, 08:01:24 Control Specifications: Control 1
• Hydrologic Drainage Area Peak DischargeTime of Peak Volume
• Element (M12) (CFS) (AC -FT)
• DA1 0.00580 29.6 22Jun2011, 12:07 2.7
• SITE DA1 0.00070 3.6 22Jun2011, 12:07 0.4
• POND /PARKING LOT 0.00070 3.5 22Jun2011, 12:09 0.4
• JCT DA1 0.00650 32.9 22Jun2011, 12:07 3.1
• DA2 0.00270 9.7 22Jun2011, 12:17 1.2
• SITE DA2 0.00020 1.0 22Jun2011, 12:07 0.1
• JCT DA2 0.00290 10.3 22Jun2011, 12:17 1.3
• CURB INLET 0.00940 41.1 22Jun2011, 12:08 4.4
• SITE DA3 0.00004 0.2 22Jun2011, 12:07 0.0
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• Project: 11 -0152 - Revised Simulation Run: 25 YR POST DEVELOPED
•
• Start of Run: 22Jun2011, 00:00 Basin Model: POST DEVELOPED
• End of Run: 24Jun2011, 00:00 Meteorologic Model: 25YR
• Compute Time: 17Aug2011, 08:01:14 Control Specifications: Control 1
• Hydrologic Drainage Area Peak DischargeTime of Peak Volume
• Element (MI2) (CFS) (AC -FT)
• DA1 0.00580 25.2 22Jun2011, 12:07 2.3
• SITE DA1 0.00070 3.1 22Jun2011, 12:07 0.3
• POND /PARKING LOT 0.00070 3.0 22Jun2011, 12:09 0.3
• JCT DA1 0.00650 28.1 22Jun2011, 12:07 2.6
• DA2 0.00270 8.2 22Jun2011, 12:18 1.0
• SITE DA2 0.00020 0.8 22Jun2011, 12:07 0.1
• JCT DA2 0.00290 8.7 22Jun2011, 12:17 1.1
CURB INLET 0.00940 34.9 22Jun2011, 12:08 3.7
• SITE DA3 0.00004 0.2 22Jun2011, 12:07 0.0
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• Project: 11 -0152 - Revised Simulation Run: 10 YR POST DEVELOPED
•
Start of Run: 22Jun2011, 00:00 Basin Model: POST DEVELOPED
End of Run: 24Jun2011, 00:00 Meteorologic Model: 10YR
• Compute Time: 17Aug2011, 08:01:10 Control Specifications: Control 1
• Hydrologic Drainage Area Peak DischargeTime of Peak Volume
Element (MI2) (CFS) (AC -FT)
DA1 0.00580 22.0 22Jun2011, 12:07 2.0
SITE DA1 0.00070 2.7 22Jun2011, 12:07 0.3
• POND /PARKING LOT 0.00070 2.7 22Jun2011, 12:09 0.3
JCT DA1 0.00650 24.6 22Jun2011, 12:07 2.3
• DA2 0.00270 7.1 22Jun2011, 12:18 0.8
SITE DA2 0.00020 0.7 22Jun2011, 12:07 0.1
• JCT DA2 0.00290 7.5 22Jun2011, 12:17 0.9
CURB INLET 0.00940 30.5 22Jun2011, 12:08 3.2
• SITE DA3 0.00004 0.1 22Jun2011, 12:07 0.0
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
1
•
•
•
• Project: 11 -0152 - Revised Simulation Run: 5 YR POST DEVELOPED
•
• Start of Run: 22Jun2011, 00:00 Basin Model: POST DEVELOPED
• End of Run: 24Jun2011, 00:00 Meteorologic Model: 5YR
• Compute Time: 17Aug2011, 08:01:28 Control Specifications: Control 1
• Hydrologic Drainage Area Peak DischargieTime of Peak Volume
• Element (M12) (CFS) (AC -FT)
• DA1 0.00580 18.2 22Jun2011, 12:07 1.6
• SITE DA1 0.00070 2.3 22Jun2011, 12:07 0.2
• POND /PARKING LOT 0.00070 2.3 22Jun2011, 12:08 0.2
JCT DA1 0.00650 20.4 22Jun2011, 12:07 1.9
• DA2 0.00270 5.7 22Jun2011, 12:18 0.7
• SITE DA2 0.00020 0.6 22Jun2011, 12:07 0.1
• JCT DA2 0.00290 6.1 22Jun2011, 12:17 0.7
• CURB INLET 0.00940 25.2 22Jun2011, 12:08 2.6
• SITE DA3 0.00004 0.1 22Jun2011, 12:08 0.0
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• Project: 11 -0152 - Revised Simulation Run: 2 YR POST DEVELOPED
•
• Start of Run: 22Jun2011, 00:00 Basin Model: POST DEVELOPED
• End of Run: 24Jun2011, 00:00 Meteorologic Model: 2YR
Compute Time: 17Aug2011, 08:01:19 Control Specifications: Control 1
•
• Hydrologic Drainage Area Peak DischargeTime of Peak Volume
Element (MI2) (CFS) (AC -FT)
• DA1 0.00580 12.7 22Jun2011, 12:07 1.1
• SITE DA1 0.00070 1.6 22Jun2011, 12:07 0.2
• POND /PARKING LOT 0.00070 1.6 22Jun2011, 12:08 0.2
• JCT DA1 0.00650 14.4 22Jun2011, 12:07 1.3
• DA2 0.00270 3.8 22Jun2011, 12:18 0.4
• SITE DA2 0.00020 0.4 22Jun2011, 12:07 0.0
• JCT DA2 0.00290 4.0 22Jun2011, 12:17 0.5
CURB INLET 0.00940 17.5 22Jun2011, 12:08 1.8
• SITE DA3 0.00004 0.1 22Jun2011, 12:08 0.0
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• 12
•
•
•
•
•
•
•
•
•
•
•
•
• APPENDIX E:
•
• FlowMaster Calculations - Rock Prairie Gutter
• (Pre- and Post - Developed Conditions)
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• N : \Gessner Eng Data 11 \11 -0152 Stepping Stone School \Civil\DOC \11 -0152 Drainage Report - NRCS.doc
• 0 Gessner Engineering
•
•
•
•
•
•
• Cross Section for ROCK PRAIRIE - EXISTING - 25 YR
• Project Description
• Friction Method Manning Formula
• Solve For Normal Depth
• Input Data
• Channel Slope 0.00500 ft/ft
• Normal Depth 0.64 ft
• Discharge 27.20 ft /s
• Cross Section Image
•
• 334.90.
334.80
• 334.70
334.60
• 334.50
334.40
• 334.30
• , 334.20 _.
° 334.10
• 334.00
w 333.90
333.80
• 333.70.....
333.60
• 333.50
333.40
• 333.30
333.20
• 0+00 0 +10 0 +20 0 +30
• Station
•
•
•
•
•
•
•
•
•
•
•
•
•
• Bentley Systems, Inc. Haestad Methods SolBtiati4rwMaster V8i (SELECTseries 1) [08.11.01.03]
8/19/2011 11:52:54 AM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1 -203- 755 -1666 Page 1 of 1
•
•
•
•
•
I •
•
•
• Cross Section for ROCK PRAIRIE - DEVELOPED - 25 YR
• P ro j ect Descr
• Friction Method Manning Formula
• Solve For Normal Depth
•
Input Data
• Channel Slope 0.00500 ft/ft
• Normal Depth 0.65 ft
• Discharge 28.10 ft /s
• Cross Section Image
•
• 334.90
334.80
• 334.70
334.60
• 33450
334.40
334.30
• 334.20
: 8 334.10
............
• 0 > 334.00
I- 333.90
• 333.80
• 333.70
333.60
• 333.50.
333.40
• 333.30
333.20
• 0 +00 0 +10 0 +20 0 +30
• Station
•
•
•
•
•
•
•
•
•
•
•
•
• Bentley Systems, Inc. Haestad Methods SolBitot1 i r i vMaster V8i (SELECTseries 1) [08.11.01.03]
8/19/2011 11:54:06 AM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1 - 203- 755 -1666 Page 1 of 1
•
•
•
•
•
•
• 13
•
•
•
•
•
•
•
•
•
•
•
• APPENDIX F:
•
• Technical Design Summary
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• N: \Gessner Eng Data 11 \11 -0152 Stepping Stone School \Civil\DOC \11 -0152 Drainage Report - NRCS.doc
• 0 Gessner Engineering
•
•
•
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 2 — Project Administration Start (Page 2.1)
• Engineering and Design Professionals Information
Engineering Firm Name and Address: Jurisdiction
• Gessner Engineering City: Bryan
• 2501 Ashford Drive, Suite 102 XX College Station
College Station, TX 77840 Date of Submittal:
•
August 222, 2011
• Lead Engineer's Name and Contact Info.(phone, e-mail, fax): el ssa Thomas
Jeremy N. Peters, (979) 680 -8840
• jpeters @gessnerengineering.com mthomas @gessnerengineering.com
• Supporting Engineering / Consulting Firm(s): Other contacts:
•
Developer / Owner /,Applicant Information
• p to ( Apli ant N a and Addres Phone and e-mail:
• Gary dner er Fivp
e Hoc(aina g s Da niel Turner (214) 459 -0258
1910 Justin Lane daniel@steppingstoneschool.com
• Austin, TX 78757
• Property Owner(s) if not Developer / Applicant (& address): Phone and e-mail:
•
• Project Identification
• Development Name: Stepping Stone School
• Is subject property a site project, a single -phase subdivision, or part of a multi -phase subdivision?
Single Phase If multi - phase, subject property is phase of
• Legal description of subject property (phase) or Project Area:
• (see Section II, Paragraph B -3a)
• Lot 2, Block 4 of Edelweiss Business Center
•
•
• If subject property (phase) is second or later phase of a project, describe general status of all
• earlier phases. For most recent earlier phase Include submittal and review dates.
•
•
• General Location of Project Area, or subject property (phase):
• Approx. 400' northeast of the Rock Prairie /Wellborn intersection
• In City Limits? Extraterritorial Jurisdiction (acreage):
• Bryan: acres. Bryan: College Station:
• College Station: 0.607 acres. Acreage Outside ETJ:
•
•
STORMWATER DESIGN GUIDELINES Page 3 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
• Effective February 2007 As Revised February 2009
•
•
•
•
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 2 — Project Administration Continued (page 2.2)
• Project Identification (continued)
• Roadways abutting or within Project Area or Abutting tracts, platted land, or built
subject property: developments:
•
• Rock Prairie Road
• Named Regulatory Watercourse(s) & Watershed(s): Tributary Basin(s):
• Lick Creek /Bee Creek
• Plat Information For Project or Subject Property (or Phase)
•
• Preliminary Plat File #: Final Plat File #: Date:
• Name: Status and Vol /Pg:
If two plats, second name: File #:
• Status: Date:
• Zoning Information For Project or Subject Property (or Phase)
• Zoning Type: A -P, C -1 Existing or Proposed? Existing Case Code:
• Case Date Status:
•
• Zoning Type: Existing or Proposed? Case Code:
• Case Date Status:
• Stormwater Management Planning For Project or Subject Property (or Phase)
• Planning Conference(s) & Date(s): Participants:
• PAC: June 22, 2011
•
•
• Preliminary Report Required? Submittal Date Review Date
• Review Comments Addressed? Yes No In Writing? When?
• Compliance With Preliminary Drainage Report. Briefly describe (or attach documentation
explaining) any deviation(s) from provisions of Preliminary Drainage Report, if any.
•
•
•
•
•
•
•
•
• STORMWATER DESIGN GUIDELINES Page 4 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
•
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 2 — Project Administration Continued (page 2.3)
• Coordination For Project or Subject Property (or Phase)
• Note: For any Coordination of stormwater matters indicated below, attach documentation
describing and substantiating any agreements, understandings, contracts, or approvals.
• Dept. Contact: Date: Subject:
Coordination 7/14/11,
• With Other Engr. Josh Norton 71811 Detention Design
• Departments of
Jurisdiction
• City (Bryan or
• College Station)
• Coordination With Summarize need(s) & actions taken (include contacts & dates):
Non- jurisdiction
• City Needed?
Yes No XX
• Coordination with Summarize need(s) & actions taken (include contacts & dates):
• Brazos County
Needed?
• Yes No XX
• Coordination with Summarize need(s) & actions taken (include contacts & dates):
• TxDOT Needed?
• Yes No XX
• Coordination with Summarize need(s) & actions taken (include contacts & dates):
• TAMUS Needed?
• Yes No XX
• Permits For Project or Subject Property (or Phase)
• As to stormwater management, are permits required for the proposed work from any of the entities
listed below? If so, summarize status of efforts toward that objective in spaces below.
• Entity Permitted or Status of Actions (include dates) a
Approved .
• US Army Crops of
• Engineers
• No XX Yes
US Environmental
• Protection Agency
• No XX Yes
• Texas Commission on
Environmental Quality
• No XX Yes
• Brazos River
• Authority
• No XX Yes
•
•
• STORMWATER DESIGN GUIDELINES Page 5 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
•
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 3 — Property Characteristics Start (Page 3.1)
• Nature and Scope of Proposed Work
• Existing: Land proposed for development currently used, including extent of impervious cover?
• Grass, pervious
• Site Redevelopment of one platted lot, or two or more adjoining platted lots.
• Development XX Building on a single platted lot of undeveloped land.
• Project Building on two or more platted adjoining lots of undeveloped land.
• (select all Building on a single lot, or adjoining lots, where proposed plat will not form
applicable) a new street (but may include ROW dedication to existing streets).
• Other (explain):
•
• Subdivision Construction of streets and utilities to serve one or more platted lots.
Development Construction of streets and utilities to serve one or more proposed lots on
• Project lands represented by pending plats.
• Site projects: building use(s), approximate floor space, impervious cover ratio.
• Describe Subdivisions: number of lots by general type of use, linear feet of streets and
Nature and drainage easements or ROW.
• Size of
• Proposed 5,968 SF school /daycare with parking lot, 75% impervious
Project
•
• Is any work planned on land that is not platted If yes, explain:
or on land for which platting is not pending?
•
XX No Yes
• FEMA Floodplains
• Is any part of subject property abutting a Named Regulatory Watercourse
• (Section II, Paragraph B1) or a tributary thereof? No XX Yes
• Is any part of subject property in floodplain No XX Yes Rate Map
area of a FEMA - regulated watercourse?
• Encroachment(s) Encroachment purpose(s): Building site(s) Road crossing(s)
• into into Floodplain
areas planned? Utility crossing(s) Other (explain):
• No XX
• Yes
• If floodplain areas not shown on Rate Maps, has work been done toward amending the FEMA-
• approved Flood Study to define allowable encroachments in proposed areas? Explain.
• N/A
•
•
•
•
• STORMWATER DESIGN GUIDELINES Page 6 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
•
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 3 — Property Characteristics Continued (Page 3.2)
• Hydrologic Attributes of Subject Property (or Phase)
• Has an earlier hydrologic analysis been done for larger area including subject property?
• Yes Reference the study (& date) here, and attach copy if not already in City files.
•
• Is the stormwater management plan for the property in substantial conformance with the
• earlier study? Yes No If not, explain how it differs.
•
•
•
If subject property is not part of multi -phase project, describe stormwater management
• NO plan for the property in Part 4.
If property part of plan
multi-phase project, provide overview of stormwater management • P P Y is P P P j P 9 P
for Project Area here. In Part 4 describe how plan for subject property will comply
• therewith.
•
•
•
•
• Do existing topographic features on subject property store or detain runoff? XX No Yes
Describe them (include approximate size, volume, outfall, model, etc).
•
•
• Any known drainage or flooding problems in areas near subject property? XX No Yes
• Identify:
•
• Based on location of study property in a watershed, is Type 1 Detention (flood control) needed?
• (see Table B -1 in Appendix B)
• Detention is required. Need must be evaluated. XX Detention not required.
• What decision has been reached? By whom?
• N/A
• If the need for
Type 1 Detention How was determination made?
• must be evaluated: N/A
•
•
•
•
• STORMWATER DESIGN GUIDELINES Page 7 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
•
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 3 — Property Characteristics Continued (Page 3.3)
• Hydrologic Attributes of Subject Property (or Phase) (continued)
• Does subject property straddle a Watershed or Basin divide? No XX Yes If yes,
describe splits below. In Part 4 describe design concept for handling this.
• Watershed or Basin Larger acreage Lesser acreage
• On boundary /unable to determine
Lick Creek /Bee Creek arcs
•
•
• Above - Project Areas(Section II, Paragraph B3 -a)
• Does Project Area (project or phase) receive runoff from upland areas? XX No Yes
• Size(s) of area(s) in acres: 1) 2) 3) 4)
• Flow Characteristics (each instance) (overland sheet, shallow concentrated, recognizable
• concentrated section(s), small creek (non - regulatory), regulatory Watercourse or tributary);
• Overland flow
•
• Flow determination: Outline hydrologic methods and assumptions:
• Property is high point in basin, sheet flows northeast to Edelweiss and south to
• Rock Prairie Road.
• Does storm runoff drain from public easements or ROW onto or across subject property?
• XX No Yes If yes, describe facilities in easement or ROW:
•
•
• Are changes in runoff characteristics subject to change in future? Explain
• No
•
• Conveyance Pathways (Section II, Paragraph C2)
Must runoff from study property drain across lower properties before reaching a Regulatory
• Watercourse or tributary? No XX Yes
• Describe length and characteristics of each conveyance pathway(s). Include ownership of
property(ies).
• Sheet flow to shallow concentrated flow at back of Tots and drainage easement.
•
•
•
•
•
•
• STORMWATER DESIGN GUIDELINES Page 8 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
•
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 3 — Property Characteristics Continued (Page 3.4)
• Hydrologic Attributes of Subject Property (or Phase) (continued)
• Conveyance Pathways (continued)
Do drainage If yes, for what part of length? % Created by? plat, or
• easements instrument. If instrument(s), describe their provisions.
• exist for any
part of
• pathway(s)?
XX No
• Yes
• Where runoff must cross lower properties, describe characteristics of abutting lower
• property(ies). (Existing watercourses? Easement or Consent aquired ?)
• Pathway All overland flow and shallow concentrated flow, grassy and lightly
• Areas landscaped
•
•
•
Describe any built or improved drainage facilities existing near the property (culverts,
• bridges, lined channels, buried conduit, swales, detention ponds, etc).
•
•
•
• Nearby
• Drainage Do any of these have hydrologic or hydraulic influence on proposed stormwater
Facilities
• design? XX No Yes If yes, explain:
•
•
•
•
•
•
•
•
•
•
•
•
•
• STORMWATER DESIGN GUIDELINES Page 9 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
•
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Start (Page 4.1)
• Stormwater Management Concept
• Discharge(s) From Upland Area(s)
• If runoff is to be received from upland areas, what design drainage features will be used to
accommodate it and insure it is not blocked by future development? Describe for each area,
• flow section, or discharge point.
•
• N/A
•
•
•
• Discharge(s) To Lower Property(ies) (Section II, Paragraph El)
Does project include drainage features (existing or future) proposed to become public via
• platting? XX No Yes Separate Instrument? XX No Yes
• Per Guidelines reference above, how will Establishing Easements (Scenario 1)
runoff be discharged to neighboring XX Pre - development Release (Scenario 2)
• property(ies)? Combination of the two Scenarios
• Scenario 1: If easements are proposed, describe where needed, and provide status of actions
• on each. (Attached Exhibit # )
•
•
• Scenario 2: Provide general description of how release(s) will be managed to pre - development
• conditions (detention, sheet flow, partially concentrated, etc.). (Attached Exhibit # )
•
• Detention, (C -05 B)
•
•
• Combination: If combination is proposed, explain how discharge will differ from pre -
development conditions at the property line for each area (or point) of release.
•
•
•
• If Scenario 2, or Combination are to be used, has proposed design been coordinated with
owner(s) of receiving property(ies)? XX No Yes Explain and provide
• documentation.
•
•
•
•
• STORMWATER DESIGN GUIDELINES Page 10 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
•
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.2)
• Stormwater Management Concept (continued)
• Within Protect Area Of Multi -Phase Project
• Identify gaining Basins or Watersheds and acres shifting:
Will project result
• in shifting runoff
• between Basins or
between What design and mitigation is used to compensate for increased runoff
• Watersheds? from gaining basin or watershed?
• XX No
• Yes
• How will runoff from Project 1. With facility(ies) involving other development projects.
• Area be mitigated to pre- 2. XX Establishing features to serve overall Project Area.
development conditions?
• Select any or all of 1, 2, 3. On phase (or site) project basis within Project Area.
• and /or 3, and explain below.
1. Shared facility (type & location of facility; design drainage area served; relationship to size of
• Project Area): (Attached Exhibit # )
•
•
•
4111 2. For Overall Project Area (type & location of facilities): (Attached Exhibit # )
• Detention pond (C -05 B), south side of site
•
• 3. By phase (or site) project: Describe planned mitigation measures for phases (or sites) in
• subsequent questions of this Part.
• Are aquatic echosystems proposed? No Yes In which phase(s) or
project(s)?
•
• Are other Best Management Practices for reducing stormwater pollutants proposed?
• a No Yes Summarize type of BMP and extent of use:
cn
• ca)
co
• a) o
Z
• . x If design of any runoff - handling facilities deviate from provisions of B -CS Technical
X Specifications, check type facility(ies) and explain in later questions.
• Detention elements Conduit elements Channel features
• Swales Ditches Inlets Valley gutters Outfalls
• Culvert features Bridges Other
•
•
• STORMWATER DESIGN GUIDELINES Page 11 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
r•
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.3)
• Stormwater Management Concept (continued)
• Within Protect Area Of Multi -Phase Project (continued)
Will Project Area include bridge(s) or culvert(s)? XX No Yes Identify type and
• general size and In which phase(s).
•
•
• If detention /retention serves (will serve) overall Project Area, describe how it relates to subject
• phase or site project (physical location, conveyance pathway(s), construction sequence):
• Front pond, release to Rock Prairie
•
•
• Within Or Serving Subject Property (Phase, or Site)
• If property part of larger Project Area, is design in substantial conformance with earlier analysis
• and report for larger area? Yes X No, then summarize the difference(s):
•
N/A
•
• Identify whether each of the types of drainage features listed below are included, extent of use,
• and general characteristics.
• Typical shape? Surfaces?
•
3 Steepest side slopes: Usual front slopes: Usual back slopes:
• CO
CU
>-
• Flow line slopes: least Typical distance from travelway:
• o typical greatest
(Attached Exhibit # )
( f ) z
• o
cri XI
X Are longitudinal culvert ends in compliance with B -CS Standard Specifications?
• �' Yes No, then explain:
•
At intersections or otherwise, do valley gutters cross arterial or collector streets?
• 3 } No XX Yes If yes explain:
• X Flows discharge to Rock Prairie, then to Edelweiss Avenue
•
X Are valley gutters proposed to cross any street away from an intersection?
• z XX No Yes Explain: (number of locations ?)
w
• m
•
•
•
• STORMWATER DESIGN GUIDELINES Page 12 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.4)
• Stormwater Management Concept (continued)
• Within Or Serving Subject Property (Phase, or Site) (continued)
• Gutter line slopes: Least Usual 0.5% Greatest
• Are inlets recessed on arterial and collector streets? XX Yes No If "no ",
• identify where and why.
• Will inlets capture 10 -year design stormflow to prevent flooding of intersections (arterial
• with arterial or collector)? Yes XX No If no, explain where and why not.
• ) Existing 10 yr Q =33.5 cfs, inlet capacity = 22.7 cfs
• ai Will inlet size and placement prevent exceeding allowable water spread for 10 -year
m design storm throughout site (or phase)? Yes XX No If no, explain.
• Existing inlet is over capacity
• I Saq curves: Are inlets placed at low points? Yes No Are inlets and
• , conduit sized to prevent 100 -year stormflow from ponding at greater than 24 inches?
• Yes No Explain "no" answers.
• N N/A
a)
• g
Will 100 - stormflow be contained in combination of ROW and buried conduit on
• Q whole length of all streets? Yes XX No If no, describe where and why.
• Existing 100 yr Q exceeds Rock Prairie R.O.W. capacity
•
• Do designs for curb, gutter, and inlets comply with B -CS Technical Specifications?
Yes No If not, describe difference(s) and attach justification.
•
•
• Are any 12 -inch laterals used? No Yes Identify length(s) and where
used.
• r.
• Pipe runs between system Typical Longest
• a access points (feet): yp g
E Are junction boxes used at each bend? Yes No If not, explain where
• u I and why.
• c o
al
• E
• ° Are downstream soffits at or below upstream soffits? Least amount that hydraulic
Yes No If not, explain where and why: grade line is below gutter line
• — (system- wide):
•
•
•
• STORMWATER DESIGN GUIDELINES Page 13 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
•
• SECTION IX
• APPENDIX D — TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.5)
• Stormwater Management Concept (continued)
• Within Or Serving Subject Property (Phase, or Site) (continued)
• Describe watercourse(s), or system(s) receiving system discharge(s) below
(include design discharge velocity, and angle between converging flow lines).
• U
as 1) Watercourse (or system), velocity, and angle?
• 0
• a E 2) Watercourse (or system), velocity, and angle?
c o
• 6
U 0
E - 3) Watercourse (or system), velocity, and angle?
• T2
• c a 0
m o
• -0 n
E For each outfall above, what measures are taken to prevent erosion or scour of
• .2 N receiving and all facilities at juncture?
• 1 )
• 2)
a
m
•
0 3)
• Are swale(s) situated along property lines between properties? No Yes
• Number of instances: For each instance answer the following questions.
• Surface treatments (including low -flow flumes if any):
• c .
u,
• m
• u, (n Flow line slopes (minimum and maximum):
c
•
• o
o
• Z Outfall characteristics for each (velocity, convergent angle, & end treatment).
• a X
co
X
I
• Q Will 100 -year design storm runoff be contained within easement(s) or platted drainage
ROW in all instances? Yes No If "no" explain:
•
•
•
•
•
• STORMWATER DESIGN GUIDELINES Page 14 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
•
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.6)
• Stormwater Management Concept (continued)
• Within Or Serving Subject Property (Phase, or Site) (continued)
• Are roadside ditches used? No Yes If so, provide the following:
• a Is 25 -year flow contained with 6 inches of freeboard throughout ? Yes No
: ILI Are top of banks separated from road shoulders 2 feet or more? Yes No
• )
a) Are all ditch sections trapezoidal and at least 1.5 feet deep? Yes No
• N For any "no" answers provide location(s) and explain:
a
o
• o
o!
• If conduit is beneath a swale, provide the following information (each instance).
• Instance 1 Describe general location, approximate length:
•
co
• >- Is 100 -year design flow contained in conduit/swale combination? Yes No
• If "no" explain:
N
• o o Space for 100 -year storm flow? ROW Easement Width
• z c Swale Surface type, minimum Conduit Type and size, minimum and maximum
X I m and maximum slopes: slopes, design storm:
• X o
• • a
c m Inlets Describe how conduit is loaded (from streets /storm drains, inlets by type):
• c >.
o c
• U 1
R
• a o Access Describe how maintenance access is provided (to swale, into conduit):
0
m
• o E
0 • 0
• •E .- Instance 2 Describe general location, approximate length:
• a E
m
• H
• c 33 Is 100 - year design flow contained in conduit/swale combination? Yes No
• —° ` If "no" explain:
m a
c
• E Space for 100 -year storm flow? ROW Easement Width
• 0 ` Swale Surface type, minimum Conduit Type and size, minimum and maximum
• m and maximum slopes: slopes, design storm:
•
O a Inlets Describe how conduit is loaded (from streets /storm drains, inlets by type):
• .) c
3 °
• `�
°'
• Q Access Describe how maintenance access is provided (to swale, into conduit):
•
•
•
• STORMWATER DESIGN GUIDELINES Page 15 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
f •
•
•
•
SECTION IX
• APPENDIX D — TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.7)
• Stormwater Management Concept (continued)
• Within Or Serving Subject Property (Phase, or Site) (continued)
• If "yes" provide the following information for each instance:
Instance 1 Describe general location, approximate length, surfacing:
•
• as
n
• o W
ui Is 100 -year design flow contained in swale? Yes No Is swale wholly
• o c >_ within drainage ROW? Yes No Explain "no" answers:
0
• a)
>
• aa) Access Describe how maintenance access is provide:
0
• Z
2 X
• 8 X Instance 2 Describe general location, approximate length, surfacing:
.c
• ai
0
• a)
• 0 c (1)
m Is 100 -year design flow contained in swale? Yes No Is swale wholly
•
cu within drainage ROW? Yes No Explain "no" answers:
o
• N O
• = O Access Describe how maintenance access is provided:
U_
• 0_
• Instance 3, 4, etc. If swales are used in more than two instances, attach sheet
• providing all above information for each instance.
• "New" channels: Will any area(s) of concentrated flow be channelized (deepened,
widened, or straightened) or otherwise altered? No Yes If only slightly
• shaped, see "Swales" in this Part. If creating side banks, provide information below.
• c Will design replicate natural channel? Yes No If "no ", for each instance
o a describe section shape & area, flow line slope (min. & max.), surfaces, and 100 -year
• o w design flow, and amount of freeboard:
• ° - Instance 1:
c }
• E
a>
• o Instance 2:
n
• E
• c X
m X I Instance 3:
• U
•
•
•
• STORMWATER DESIGN GUIDELINES Page 16 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
f •
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.8)
• Stormwater Management Concept (continued)
• Within Or Serving Subject Property (Phase, or Site) (continued)
Existing channels (small creeks): Are these used? No Yes
• If "yes" provide the information below.
• Will small creeks and their floodplains remain undisturbed? Yes No How
• many disturbance instances? Identify each planned location:
•
• For each location, describe length and general type of proposed improvement
• (including floodplain changes):
•
• For each location, describe section shape & area, flow line slope (min. & max.),
• surfaces, and 100 -year design flow.
•
•
m
• c Watercourses (and tributaries): Aside from fringe changes, are Regulatory
• • Watercourses proposed to be altered? No Yes Explain below.
• c Submit full report describing proposed changes to Regulatory Watercourses. Address
• • existing and proposed section size and shape, surfaces, alignment, flow line changes,
• length affected, and capacity, and provide full documentation of analysis procedures
• ° and data. Is full report submitted? Yes No If "no" explain:
a
•
m
• . All Proposed Channel Work: For all proposed channel work, provide information
• requested in next three boxes.
• If design is to replicate natural channel, identify location and length here, and describe
design in Special Design section of this Part of Report.
•
•
• Will 100 -year flow be contained with one foot of freeboard? Yes No If
• not, identify location and explain:
•
•
• Are ROW / easements sized to contain channel and required maintenance space?
Yes No If not, identify location(s) and explain:
•
•
•
•
• STORMWATER DESIGN GUIDELINES Page 17 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
•
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.9)
• Stormwater Management Concept (continued)
• Within Or Serving Subject Property (Phase, or Site) (continued)
• How many facilities for subject property project? 2 For each provide info. below.
• For each dry -type facilitiy: Facility 1 Facility 2
Acres served & design volume + 10% 0.44 0.008 Ac. ft.
• 100 -yr volume: free flow & plugged 0.008 0.008
• Design discharge (10 yr & 25 yr) 2.7 cfs 3.0 cfs
• Spillway crest at 100 -yr WSE? yes XX no yes no
• Berms 6 inches above plugged WSE? yes _X no yes no
• Explain any "no" answers:
• Elevations constrained due to adjacent property grades
0)
• -
r
• 1 For each facility what is 25 -yr design Q, and design of outlet structure?
• ,9 Facility 1: 3.1 cfs, rectangular weir
0
• z Facility 2:
• Do outlets and spillways discharge into a public facility in easement or ROW?
Facility 1: X Yes No Facility 2: XX Yes No
•
73 If "no" explain:
• N
0
a
• O
a For each, what is velocity of 25 -yr design discharge at outlet? & at spillway?
• a Facility 1: 2.6 fps & Facility 2: &
F. • Tr, Are energy dissipation measures used? No XX Yes Describe type and
u_ location:
• c
0
• c
0
m
• °
2 For each, is spillway surface treatment other than concrete? Yes or no, and describe:
• Q Facility 1:
• Facility 2: N/A
• For each, what measures are taken to prevent erosion or scour at receiving facility?
• Facility 1:
• Facility 2:
• If berms are used give heights, slopes and surface treatments of sides.
Facility 1: 1', 4:1
•
• Facility 2:
•
•
• STORMWATER DESIGN GUIDELINES Page 18 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
•
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.10)
• Stormwater Management Concept (continued)
• Within Or Serving Subject Property (Phase, or Site) (continued)
Do structures comply with B -CS Specifications? Yes or no, and explain if "no ":
•
Facility 1; Yes
• N
m
• ii • 5 Facility 2:
• c
o c
• - o
• o For additional facilities provide all same information on a separate sheet.
Are parking areas to be used for detention? No XX Yes What is
• maximum depth due to required design storm? 0.4'
• Roadside Ditches: Will culverts serve access driveways at roadside ditches?
• No Yes If "yes ", provide information in next two boxes.
Will 25 -yr. flow pass without flowing over driveway in all cases? Yes No
• Without causing flowing or standing water on public roadway? Yes No
• Designs & materials comply with B -CS Technical Specifications? Yes No
• Explain any "no" answers:
•
• ,--
• 0,
c
• o Are culverts parallel to public roadway alignment? Yes No Explain:
U N
• N }
f6
• Q Creeks at Private Drives: Do private driveways, drives, or streets cross drainage
• 0 o ways that serve Above - Project areas or are in public easements/ ROW?
No Yes If "yes" provide information below.
• N X I How many instances? Describe location and provide information below.
• > Location 1:
• m Location 2:
• Q
• Location 3:
• For each location enter value for: 1 2 3
• Design year passing without toping travelway?
• Water depth on travelway at 25 -year flow?
• Water depth on travelway at 100 -year flow?
• For more instances describe location and same information on separate sheet.
•
•
• STORMWATER DESIGN GUIDELINES Page 19 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
•
•
•
SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.11)
• Stormwater Management Concept (continued)
• Within Or Serving Subject Property (Phase, or Site) (continued)
• Named Regulatory Watercourses (& Tributaries): Are culverts proposed on these
facilities? No Yes, then provide full report documenting assumptions,
• criteria, analysis, computer programs, and study findings that support proposed
• design(s). Is report provided? Yes No If "no ", explain:
•
• Arterial or Major Collector Streets: Will culverts serve these types of roadways?
• No Yes How many instances? For each identify the
m location and provide the information below.
• a m Instance 1:
>- o_
• N Instance 2:
• o Instance 3:
• z . Yes or No for the 100 -year design flow: 1 2 3
• X o Headwater WSE 1 foot below lowest curb top?
C
• X Spread of headwater within ROW or easement?
• • Is velocity limited per conditions (Table C -11)?
rn
• N m Explain any "no" answer(s):
o c
• U o
o
• I6 o
a o
o - Minor Collector or Local Streets: Will culverts serve these types of streets?
• .0_ u) No Yes How many instances? for each identify the
• — a location and provide the information below:
CL
• T Instance 1 :
•
N c Instance 2:
• • o Instance 3:
• 11) 0 For each instance enter value, or "yes" / "no" for: 1 2 3
O CO
c
• Design yr. headwater WSE 1 ft. below curb top?
• . 0 100 -yr. max. depth at street crown 2 feet or less?
E Product of velocity (fps) & depth at crown (ft) = ?
• • Is velocity limited per conditions (Table C -11)?
• Limit of down stream analysis (feet)?
• Explain any "no" answers:
•
•
•
•
• STORMWATER DESIGN GUIDELINES Page 20 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
r •
•
•
SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.12)
• Stormwater Management Concept (continued)
• Within Or Serving Subject Property (Phase, or Site) (continued)
• All Proposed Culverts: For all proposed culvert facilities (except driveway /roadside
ditch intersects) provide information requested in next eight boxes.
• Do culverts and travelways intersect at 90 degrees? Yes No If not,
• identify location(s) and intersect angle(s), and justify the design(s):
•
• Does drainage way alignment change within or near limits of culvert and surfaced
• approaches thereto? No Yes If "yes" identify location(s), describe
• change(s), and justification:
•
• Are flumes or conduit to discharge into culvert barrel(s)? No Yes If yes,
• identify location(s) and provide justification:
•
• Are flumes or conduit to discharge into or near surfaced approaches to culvert ends?
• No Yes If "yes" identify location(s), describe outfall design treatment(s):
• c
c
• o
•
> Is scour /erosion protection provided to ensure long term stability of culvert structural
• 0 components, and surfacing at culvert ends? Yes No If "no" Identify
• locations and provide justification(s):
•
• Will 100 -yr flow and spread of backwater be fully contained in street ROW, and /or
• drainage easements/ ROW? Yes No if not, why not?
•
•
Do appreciable hydraulic effects of any culvert extend downstream or upstream to
• neighboring land(s) not encompassed in subject property? No Yes If
• "yes" describe location(s) and mitigation measures:
•
•
• Are all culvert designs and materials in compliance with B -CS Tech. Specifications?
• Yes No If not, explain in Special Design Section of this Part.
•
•
• STORMWATER DESIGN GUIDELINES Page 21 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
r •
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.13)
• Stormwater Management Concept (continued)
• Within Or Serving Subject Property (Phase, or Site) (continued)
Is a bridge included in plans for subject property project? No Yes
• If "yes" provide the following information.
• Name(s) and functional classification of the roadway(s)?
•
•
• What drainage way(s) is to be crossed?
• m
rn
• m `
• A full report supporting all aspects of the proposed bridge(s) (structural, geotechnical,
• hydrologic, and hydraulic factors) must accompany this summary report. Is the report
provided? Yes No If "no" explain:
•
•
• Is a Stormwater Provide a general description of planned techniques:
• Pollution Prevention
3 Plan (SW3P)
• 3 established for
• a, project construction?
• No Yes
• Special Designs — Non - Traditional Methods
• Are any non - traditional methods (aquatic echosystems, wetland -type detention, natural stream
replication, BMPs for water quality, etc.) proposed for any aspect of subject property project?
• No Yes If "yes" list general type and location below.
•
•
•
•
• Provide full report about the proposed special design(s) including rationale for use and
• expected benefits. Report must substantiate that stormwater management objectives will not
• be compromised, and that maintenance cost will not exceed those of traditional design
solution(s). Is report provided? Yes No If "no" explain:
•
•
•
•
•
• STORMWATER DESIGN GUIDELINES Page 22 of 26 APPENDIX. D. TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
r •
•
•
•
SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.14)
• Stormwater Management Concept (continued)
• Within Or Serving Subject Property (Phase, or Site) (continued)
• Special Designs — Deviation From B -CS Technical Specifications
If any design(s) or material(s) of traditional runoff - handling facilities deviate from provisions of
• B -CS Technical Specifications, check type facility(ies) and explain by specific detail element.
• Detention elements Drain system elements Channel features
Culvert features Swales Ditches Inlets Outfalls
•
Valley gutters Bridges (explain in bridge report)
• In table below briefly identify specific element, justification for deviation(s).
• Specific Detail Element Justification for Deviation (attach additional sheets if needed)
• 1 )
•
• 2)
• 3 )
•
• 4)
•
• 5 )
• Have elements been coordinated with the City Engineer or her /his designee? For each item
• above provide "yes" or "no ", action date, and staff name:
• 1)
• 2)
3)
•
4)
• 5)
• Design Parameters
• Hydrology
• Is a map(s) showing all Design Drainage Areas provided? XX Yes No
• Briefly summarize the range of applications made of the Rational Formula:
• Used NRCS, TR -55
•
•
• What is the size and location of largest Design Drainage Area to which the Rational Formula
• has been applied? acres Location (or identifier):
•
•
• STORMWATER DESIGN GUIDELINES Page 23 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
•
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.15)
• Design Parameters (continued)
• Hydrology (continued)
• In making determinations for time of concentration, was segment analysis used?
No XX Yes In approximately what percent of Design Drainage Areas? 50
• As to intensity- duration - frequency and rain depth criteria for determining runoff flows, were any
• criteria other than those provided in these Guidelines used? XX No Yes If "yes"
identify type of data, source(s), and where applied:
•
•
•
•
• For each of the stormwater management features listed below identify the storm return
frequencies (year) analyzed (or checked), and that used as the basis for design.
• Feature Analysis Year(s) Design Year
• Storm drain system for arterial and collector streets N/A
• Storm drain system for local streets N/A
• Open channels N/A
• Swale /buried conduit combination in lieu of channel N/A
• Swales N/A
• Roadside ditches and culverts serving them N/A
• Detention facilities: spillway crest and its outfall N/A
• Detention facilities: outlet and conveyance structure(s) 100 yr. 100 yr.
• Detention facilities: volume when outlet plugged 100 yr. 100 yr.
• Culverts serving private drives or streets N/A
• Culverts serving public roadways N/A
Bridges: provide in bridge report. N/A
• Hydraulics
• What is the range of design flow velocities as outlined below?
• Design flow velocities; Gutters Conduit Culverts Swales Channels
• Highest (feet per second)
• Lowest (feet per second)
• Streets and Storm Drain Systems Provide the summary information outlined below:
• Roughness coefficients used: For street gutters: 0.011
• For conduit type(s) Coefficients:
•
•
•
• STORMWATER DESIGN GUIDELINES Page 24 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
•
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.16)
• Design Parameters (continued)
• Hydraulics (continued)
• Street and Storm Drain Systems (continued)
For the following, are assumptions other than allowable per Guidelines?
• Inlet coefficients? XX No Yes Head and friction losses XX No Yes
• Explain any "yes" answer:
•
• In conduit is velocity generally increased in the downstream direction? Yes No
• Are elevation drops provided at inlets, manholes, and junction boxes? Yes No
Explain any "no" answers:
•
•
• Are hydraulic grade lines calculated and shown for design storm? Yes No
For 100 -year flow conditions? Yes No Explain any "no" answers:
•
•
• What tailwater conditions were assumed at outfall point(s) of the storm drain system? Identify
each location and explain:
•
• N/A
•
• Open Channels If a HEC analysis is utilized, does it follow Sec VI.F.5.a? Yes No
• Outside of straight sections, is flow regime within limits of sub - critical flow? Yes No
• If "no" list locations and explain:
•
• Culverts If plan sheets do not provide the following for each culvert, describe it here.
• For each design discharge, will operation be outlet (barrel) control or inlet control?
•
•
• Entrance, friction and exit losses:
•
•
•
• Bridges Provide all in bridge report
•
•
•
• STORMWATER DESIGN GUIDELINES Page 25 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
r •
•
•
SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.17)
•
Design Parameters (continued)
• Computer Software
What computer software has been used in the analysis and assessment of stormwater
• management needs and /or the development of facility designs proposed for subject property
• project? List them below, being sure to identify the software name and version, the date of the
version, any applicable patches and the publisher
•
• HEC -HMS, v. 3.5, FlowMaster, v. 8i
•
•
•
• Part 5 — Plans and Specifications
• Requirements for submittal of construction drawings and specifications do not differ due to use of a
• Technical Design Summary Report. See Section III, Paragraph C3.
•
Part 6 — Conclusions and Attestation
• Conclusions
• Add any concluding information here:
•
•
•
•
•
•
• Attestation
Provide attestation to the accuracy and completeness of the foregoing 6 Parts of this Technical
• Design Summary Drainage Report by signing and sealing below.
• "This report (plan) for the drainage design of the development named in Part B was prepared
by me (or under my supervision) in accordance with provisions of the Bryan /College Station
• Unified Drainage Desig Guidelines for the owners of the property. All licenses and permits
• required , -ny and , I state and federal regulatory agencies for the propos ainage
improve • is have een issued or fall under applicable general permits." N ��
• (Affix Seal) ! E Of 'f Efi7 ,
• 401101° et.7 • Li. ns d -� ofessional • Engineer .• R.... ET ...: •
" j
E q
• / 21
• State of Texas PE No. / Ov 2 (� 1 , 4 ► •`!�`e 0 �,.,•
1 % /�NtAL EEN�'
• •
• STORMWATER DESIGN GUIDELINES Page 26 of 26 APPENDIX. D. TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•