HomeMy WebLinkAboutDrainage and Detention Pond AnalysisDrainage and
Detention Pond Analysis
for
The Barracks Subdivision
College Station, Texas
July, 2008
(Revised August, 2008)
Developer:
Greens Prairie Investors, Inc.
4490 Castlegate Drive
College Station, Texas 77845
(979) 690-7250
Prepared By:
Civil Development, Ltd.
2033 Harvey Mitchell Parkway South
College Station, Texas 77840
(979) 764-7743
The Barracks Subdivision
Storm Sewer and Detention System Report
GENERAL
Location:
Description:
• Area:
• Proposed Land Use:
• #of Lots:
• Existing Land Use :
• Land Description:
Adjoining Land Use:
Primary Drainage Facility:
Flood Hazard Information:
FEMAFIRM:
Floodplain:
The Barracks Subdivision is located on the north side of Rock Prairie Road
approximately 114 mile west of Wellborn Road. It is adjacent to the Williamsgate
Subdivision.
13.4 acres
Residential Townhomes
108
Vacant. The most recent land use was a commercial water lily farm. There was an
existing barn and small frame house on the property.
The site has a gentle rise from the northwest to the southeast corners of the
property. It is generally void of trees except for a few small ones around the
perimeter. Most of the site was previously covered with 44 shallow, lined ponds
for the purpose of raising lilies. Narrow maintenance roadways were built between
the ponds.
The site is bounded on the north and east by undeveloped tracts of land. The
southern boundary is Rock Prairie Road, with additional undeveloped property
across the street. The Williamsgate Subdivision is located immediately west of the
site. This is a single-family residential subdivision.
The site lies in the Bee Creek Drainage Basin, but is located near the drainage
divide between the Bee Creek and Whites Creek basins. There is a small tributary
of Bee Creek that flows northward toward Cain Road, then eastward where it
crosses under the railroad tracts and Wellborn Road.
# 48041COl82 C
No portion of any developed lots lies within the floodplain of Bee Creek.
STORM DRAINAGE DESIGN
General Information: Upon full development, there will be three independent drainage systems for the
site. These systems will outfall into the existing channel on the northwest corner
of the site. They do not flow into the detent}on pond and thus operate
independently of the detention pond system. (The detention pond system is
described later in this report.)
These systems consist of a series of inlets and junction boxes that are connected by
underground pipes as shown in Exhibit A. Phase 1 of the development will build
portions of the three systems that outfall into constructed channels that carry water
to the natural channel on the northwest comer of the site. As subsequent phases
are built, these constructed channels will be removed and replaced with. the storm
drainage system in Exhibit A.
In order to minimize the amount of fill material that had to be imported to the site,
the storm drainage system was designed to be as small and as flat as possible. As a
result, it was critical that the inlets capture as much of the water that comes to them
and minimize the bypass that had to be captured downstream. This is particularly
true of the grate inlets on the alleys. They have been designed to span much of the
alley width. These inlets consist of trench boxes with vane grates covers over
them. Street inlets will be recessed curb inlets as shown in the BCS Standard
Details.
Page 1 of 5
STORM DRAINAGE DESIGN (cont.)
Street Design: Standard cross-section (3% cross-slope, 27' B-B residential, 38' B-B collector)
Lay down curb & gutter on residential streets, standard 6" curb on the collector
Alley Design:
Tc Methodology:
Tc Minimum
Design Storm Event:
Pipe Materials:
Manning's n Value:
Runoff Coefficients:
Design Constraints:
Design Software:
Applicable Exhibits:
street.
Asphalt pavement
Standard recessed curb inlets (length varies)
Minimum slope -0.8% slope
Inverted V cross-section (5% cross-slope, 20' width, max. depth= 6")
Concrete pavement
Grate inlets (East Jordon Iron Works 6970 Vane Style Trench Assembly)
Minimum slope -0.6% slope
TR55
10 minutes
10-year
Reinforced concrete pipe under streets and alleys
0.013
0.69 for developed lots
Max. water depth in curb = 4.5 in. or 0.38 ft.
Min. flow velocity = 2.5 fps
Max. flow velocity = 15 fps
Min. freeboard at collector street culvert= 1 ft.
100-yr storm runoff maintained within the ROW (4 inches above curb)
Haestad Methods StormCAD v 4.1
This software computes the rainfall and runoff using TR-55 and the Rational
Method. Flows through the pipes are computed using Manning's Equation.
StormCAD computes pipe capacity, flowrate and velocity through each pipe, and
determines hydraulic grade line elevations at each inlet or junction box. A
summary of this output data is shown in Exhibit C.
Exhibit A -Storm Sewer Drainage Area Map
Exhibit B -Drainage Area, Gutter and Inlet Computation Worksheet
Exhibit C -Storm CAD Pipe Analysis Summary ( 10-yr and 100-yr storms)
DETENTION POND DESIGN
General Methodology As indicated above, the site's most recent use was as a commercial water lily farm.
Through consultation with the City of College Station, it was agreed that this use
would be considered the pre-development condition, thus requiring the post-
development runoff rates to be held to those experienced during the farm 's
operation. This posed some unusual circumstances that are not encountered in
most hydro logic analyzes.
Under normal operating conditions, the 44 ponds on the site maintained a shallow
pool of water that did not drain unless valves were manually opened. Above the
normal pool levels, the ponds had varying heights of storage volume before water
would begin overtopping the maintenance roadways between them. These storage
heights ranged from a minimum of 0.2 feet to 2.36 feet. This additional available
storage had a significant effect on runoff from the site.
A topographic survey of the site was conducted while the ponds were still in place.
Survey shots were taken at normal pool elevations that were estimated from the
vegetation lines along the banks. Top-of -bank elevations were also acquired.
Page 2 of 5
This data was used to estimate the total pond area, the height above normal pool
elevation, and the total storage volume above normal pool elevation. A
spreadsheet showing this information is shown in Exhibit D. The cumulative total
of this storage and the pond surfaces are as follows:
Cumulative total storage area =
Cumulative surface area (at high banks)=
Average depth of available storage =
6.21 ac-ft
4.76 ac
1.31ftor15.66 in .
This average depth provides an estimate of the amount of rainfall that could fall
over the 44 ponds before any runoff could be anticipated. It was used to formulate
a basis for subsequent estimates of overall runoff patterns.
The remaining 4.8 acres of the lily farm site included maintenance drives and a
barn with parking areas and yard. Runoff from these areas could be anticipated
during any normal rainfall event, but it is likely that some of this runoff would
make its way into one of the ponds before reaching the outfall on the opposite end
of the development. In order to account for these circumstances, the HEC-HMS
computer model was chosen to estimate runoff from this site because it can
incorporate the Initial and Constant Loss Method, which allow users to enter an
amount of initial loss before runoff begins.
In order to model the pond areas and the upland areas of the lily farm, the site was
divided into two drainage areas so that differing initial losses could be
incorporated. Refer to the Pre-Development Drainage Area Map on Exhibit D to
see these areas. Drainage Areas 101 Pnd and 101 Surface were created for the
model. DA 101Pnd was assigned an initial loss of 15.66 inches, which implies that
during a 100 yr rainfall event (11.0 inches), no runoff would be expected and there
would be 4.66 inches of available storage still available to capture water from
DA101 Surface. Since the total area of DA 101Surface is virtually the same as DA
101Pnd, the 4.66 inches of available storage was used as the initial loss for DA
101 Surface.
Runoff from other Drainage Areas around the site were estimated using the
standard SCS Curve Number Method. Input data for Pre-and Post-Development
Scenarios are shown below.
Page 3 of 5
DETENTION POND DESIGN (cont.)
HEC-HMS Analysis
Pre-Development Conditions
Drainage Area I
I Initial %
Name Area CN Loss Imperv Lag Time
(sq. mi.) (in.) (min.)
DA 100 .011 I 75 0 28
DA 101 Pnd .0074375 -15.66 0 10 --··-·· ----DA 101 Surface .0074844 -4.66 I 0 10
DA 102A .0028986 87 -52 12 --,__. -·----····--------··--·------· DA 102B .00449531 84 -38 15
DA 103 .0216039 84 -38 32 , .. __ ·----,_,, __ -DA 104 I .0216039 75 -10 20
Detention Pond Design
Outlet Control System
Pipe:
Structure:
Note :
Emergency Outfall:
Spillway Length:
Side slopes:
Spillway Elev.:
Top of Berm Elev.:
Cross slope:
Manning 's n:
Post-Development Conditions
Drainage Area
I Area I CN % Lag Time Name Im erv.
(sq. mi.) (min.)
DA600 .0108116 75 0 I 34
DA 601 .0214688 91 65 19
DA603 .0232344 84 38 34
DA604 I .0239375 75 10 19 __ _._ -
Due to the low runoff from the site in its pre-development condition, it was not
possible to capture sufficient water from the site in its post-development condition
and detain it to pre-development rates. Therefore, it became necessary to capture
water coming from off-site, detain it in a pond, and release it after the peak runoff
from the site had already passed. This required the detention pond to be located on
the upper part of the site where water from the Rock Prairie Road drainage ditches
could flow directly into it. This location also allowed greater depth and storage
volume without excessively high berms around the pond. The detention pond
system does not have an interconnection with the storm drain system until it
reaches the outfall on the northwest corner of the site.
1-24" HDPE (flowline elevation= 305.50)
1-36" HDPE (flowline elevation= 306.00)
5 'x 4' concrete box open on top
The 24" HDPE opens directly into the detention pond and serves to control
flowrates for small rainfall events. The 36" pipe opens into the outlet structure.
No water enters the 36" pipe through the structure until the surface elevation in the
pond reaches 310.0 feet, at which time it begins to flow over the top. Upon full
development, the 24" and 36" pipes will be extended to the outfall at the northwest
corner of the site. During Phase I development, the two pipes will flow into a
temporary, privately maintained channel that drains through the site.
The emergency spillway for the pond is located on the northeast comer of the
pond. It is designed to operate only when the outlet structure on the pond is
blocked, and allows overflows to spill eastward toward the future ROW of
Lieutenant A venue.
100 ft.
4H:lV
312.40 ft
313.50 ft
0.50%
0.025 (short grass)
Page 4 of 5
HEC-HMS Analysis Summary
Applicable Exhibits:
CONCLUSION
Condition
Pre-Dev.
Post-Dev.
Pond WSEL
~ I __ 10 yr _::yr I 50 yr I 100 yr I 100~1~'2erg
cfs i cfs cfs~ cfs I cfs
55 .3 1 114.4 144.8 1 180.5 I 210.2 I
52.9 . 110.0 137.4 166.4 184.8 I
309.8 1 310.7 1 311.0 1 311.7 1 312.4 I 312.9
Emergency Spillway Elev.= 3 I 2. 4 ft
Top of Berm Elevation= 3!3.5ft
Available Freeboard = 0. 6 ft.
Exhibit D -Drainage Area Map -Pre-Development
Exhibit E -Drainage Area Map -Post-Development
Exhibit F -Existing Pond Storage Worksheet
Exhibit G -Lag Time Computation Worksheet
Exhibit H -HEC-HMS Output Files -Pre-Development
Exhibit I-HEC-HMS Output Files -Post-Development
The Barracks Subdivision is being constructed on a site with an unusual prior use
that greatly affected how the drainage system was designed. Before the
installation of the water lily farm around 1980, the site was an open field much like
many other undeveloped sites in the community with normal runoff patterns.
However, when the ponds were installed for the water lilies, it changed the
drainage patterns and greatly reduced the runoff from the site. Since this was later
determined to be the pre-development condition, the approach to the drainage
system design had to be altered from those of a normal site.
The drainage system described in this report is designed in accordance with the
standards in the BCS Drainage Design Guidelines. Flowrates downstream of this
site will be less than those currently being experienced for all design storms by
over-detaining offsite runoff. As these offsite areas develop, there should be no
significant increase in runoff passing through this site as long as requirements for
detention are in place.
Page 5 of 5
* CIVll.DEva.OPMENr, Lt4. * CMl EHOIHEERIHO l DESIGN·BUILO SEIMCES
2033 Harvey Mitchell Parkway South
College Station, Texas 77840
P.O. Box 11929, College Station, Texas 77842
(979) 754.7743 Fax: (979) 764-7759
o'\DICINEDllNC\SDSl(\PROJ\C205 -ROCK PRMR1E TOWlfia.IES\ElOH l'•\C2M STOAW DRAIN ~
/
SCALE= 1 :150
STORM DRAIN
SYSTEM
SCHEMATIC
THE BARRACKS
SUBDIVISION
EXHIBIT A
Exhibit B
The Barracks Subdivision
Drainage Area Summary, Gutter Checks, Inlet Computations
Recessed Curb Inlets on Grade
10 year storm 100 year storm Gutter Depth Check Inlet Length
Area, A c le Length Area# 110 QlO 1100 Qloo Slope Y10 Y100 Provided Capacitiy Bypass
(acres) (min) (in/hr) (cfs) (in/hr) (cfs) (ft/ft) (in) (in) (ft) (cfs) (cfs)
121 0.152 0.69 10.0 8.635 0.91 11 .639 1.22 0.0080 2.1 2.4 5 2.41 0.0
131 0.361 0.69 10.0 8.635 2.15 11.639 2.90 0.0080 2.9 3.3 5 2.71 0.0
210 0.647 0.69 10.0 8.635 3.85 11.639 5.20 0.0090 3.6 4.0 10 5.93 0.0
220 0.579 0.69 10.0 8.635 3.45 11.639 4.65 0.0090 3.4 3.8 10 5.81 0.0
320 0.201 0.69 10.0 8.635 1.20 11.639 1.61 0.0080 2.4 2.6 5 2.49 0.0
Recessed Curb Inlets in Sump
10 year storm 100 year storm Gutter Depth Check Inlet Length
Area, A c le Length Length Area# 110 Qlo 1100 Qloo Slope Y10 Y100 Inlet Q10 Provided Required
(acres) (min) (in/hr) (cfs) (in/hr) (cfs) (ft/ft) (in) (in) (cfs) (ft) (ft)
120A 0.363 0.69 10.0 8.635 2.16 11.639 2.92 0.0080 2.9 3.3 6.02 10 4.5 1
1208 0.647 0.69 10.0 8.635 3.85 11.639 5.20 0.0080 3.7 4.1
140A 0.187 0.69 10.0 8.635 1.11 11.639 1.50 0.0080 2.3 2.6 4.68 5 3.50
1408 0.598 0.69 10.0 8.635 3.56 11.639 4.80 0.0080 3.5 4.0
141A 0.164 0.69 10.0 8.635 0.98 11 .639 1.32 0.0080 2.2 2.4 4.88 5 3.65
1418 0.655 0.69 10.0 8.635 3.90 11 .639 5.26 0.0080 3.7 4.1
143A 0.206 0.69 10.0 8.635 1.23 11.639 1.65 0.0080 2.4 2.7 7.31 10 5.47
1438 1.021 0.69 10.0 8.635 6.08 11.639 8.20 0.0080 4.3 4.8
144A 0.201 0.69 10.0 8.635 1.20 11.639 1.61 0.0080 2.4 2.6 6.71 10 5.02
1448 0.925 0.69 10.0 8.635 5.51 11.639 7.43 0.0080 4.2 4.7
Grate Inlets in Alleys
10 year storm 100 year storm Gutter Depth* Inlet Size Verifies ti on
Area, A c le Opening w/25% Depth over Area# 110 QlO 1100 Qloo Slope v,. Y100 Grate Type Grate Size Area Clogging Inlet
(acres) (min) (in/hr) (cfs) (in/hr) (cfs) (ft/ft) (in) (in) (sq. in) (sq. in) (in)
122 1.023 0.69 10.0 8.635 6.09 11.639 8.22 0.0060 4.6 5.1 EJJW 6970 5-18"x30" 930 698 0.73
330 0.625 0.69 10.0 8.635 3.72 11 .639 5.02 0.0060 3.8 4.3 EJIW6970 9-18"x30" 1674 1256 0.39
142 0.986 0.69 10.0 8.635 5.87 11 .639 7.92 0.0060 4.5 5.1 EJIW 6970 5-18"x30" 930 698 0.70
145 0.839 0.69 10.0 8.635 5.00 I I.639 6.74 0.0085 4.0 4.5 EJIW 6970 9-18"x30" 1674 1256 0.65
*Note: The values for y are computed with Channel Calculator in AutoCAD v. 14 using Mannings Equation (n = .014).
#of Label US Node OS Node Length Pipes ft P110 JB110 OF 1 85 2 P120 1120 JB110 28 2 P121 1121 1120 134 1 P122 1122 1121 44 1 P130 JB130 1120 79 2 P131 1131 JB130 33 1 P140 1140 JB130 324 2 P141 1141 1140 31 1 P142 1142 1141 115 1 P143 1143 1142 115 1 P144 1144 1143 41 1 P145 1145 1144 115 1 P210 1210 HW200 19 2 P220 1220 1210 46 2 P230 HW230 1220 18 2 P310 JB310 HW31 113 1 P320 1320 JB310 12 1 P330 1330 1320 41 1 us #of Label OS Node Length Pipes Node ft P110 JB110 OF 1 85 2 P120 1120 JB110 28 2 P121 1121 1120 134 1 P122 1122 1121 44 1 P130 JB130 1120 79 2 P131 1131 JB130 33 1 P140 1140 JB130 324 2 P141 1141 1140 31 1 P142 1142 1141 115 1 P143 1143 1142 115 1 P144 1144 1143 41 1 P145 1145 1144 115 1 P210 1210 HW200 19 2 P220 1220 1210 46 2 P230 HW230 1220 18 2 P310 JB310 HW31 113 1 P320 1320 JB310 12 1 P330 1330 1320 41 1 UpSt On St Pipe Size Invert Invert Elev. Elev. in ft ft 30inch 302.85 302.25 30inch 303.05 302.85 24 (-25%) 304.33 303.65 24 (-25%) 304.66 304.43 30inch 303.43 303.15 15 (-25%) 305.2 304.78 30inch 304.66 303.53 30inch 304.92 304.76 30inch 305.45 305.02 30inch 305.95 305.55 24 (-25%) 306.89 306.55 18 (-25%) 308.3 307.49 24 (-25%) 303.16 303.06 24 (-25%) 303.4 303.16 24 (-25%) 303.5 303.40 24 (-25%) 304.55 303.82 18 (-25%) 304.8 304.65 18 (-25%) 305.25 304.90 UpSt On St Dia. Invert Invert Elev. Elev. in ft ft 30inch 302.85 302.25 30inch 303.05 302.85 24 (-25%) 304.33 303.65 24 (-25%) 304.66 304.43 30inch 303.43 303.15 15 (-25%) 305.2 304.78 30inch 304.66 303.53 30inch 304.92 304.76 30inch 305.45 305.02 30inch 305.95 305.55 24 (-25%) 306.89 306.55 18 (-25%) 308.3 307.49 24 (-25%) 303.16 303.06 24 (-25%) 303.4 303.16 24 (-25%) 303.5 303.40 24 (-25%) 304.55 303.82 18 (-25%) 304.8 304.65 18 (-25%) 305.25 304.90 Exhibit C The Barracks Subdivision PIPE ANALYSIS 10-yr Design Storm Computed Slope Mannings n a ftlft cfs 0.0071 0.0130 45.3 0.0072 0.0130 45.4 0.0051 0.0130 7.0 0.0052 0.0130 6.1 0.0035 0.0130 33.8 0.0126 0.0130 2.2 0.0035 0.0130 33.0 0.0052 0.0130 28.6 0.0037 0.0130 24.2 0.0035 0.0130 18.8 0.0082 0.0130 11.6 0.0070 0.0130 5.0 0.0051 0.0130 11.4 0.0052 0.0130 7.8 0.0055 0.0130 4.6 0.0065 0.0130 4.9 0.0130 0.0130 4.9 0.0085 0.0130 3.8 100 yr Design Storm -Computed Slope Mannings n a ft/ft cfs 0.0071 0.0130 61.5 0.0072 0.0130 61.6 0.0051 0.0130 9.5 0.0052 0.0130 8.3 0.0035 0.0130 45.8 0.0126 0.0130 2.9 0.0035 0.0130 44.6 0.0052 0.0130 38.7 0.0037 0.0130 32.7 0.0035 0.0130 25.3 0.0082 0.0130 15.7 0.0070 0.0130 6.8 0.0051 0.0130 15.4 0.0052 0.0130 10.6 0.0055 0.0130 6.3 0.0065 0.0130 6.6 0.0130 0.0130 6.7 0.0085 0.0130 5.1 Design Excess UpSt UpSt On St On St Capacity Capacity Ground HGL Ground HGL V10 Elev. Elev. Elev. Elev. cfs cfs ft ft ft ft ftls 68.9 23.6 308.00 304.47 308.00 303.73 7.49 69.8 24.4 308.60 304.67 308.00 304.35 7.41 11.0 4.0 309.00 305.34 308.60 304.67 4.85 11.1 5.0 309.00 305.58 309.00 305.35 4.85 48.8 15.0 309.25 304.96 308.60 304.67 5.40 4.9 2.8 309.00 305.82 309.25 305.28 5.19 48.4 15.4 311.10 306.17 309.25 304.96 5.69 29.6 1.0 312.00 306.86 311.10 306.58 7.46 25.1 0.9 311.83 307.39 312.00 306.86 6.26 24.2 5.4 312.40 307.66 311.83 307.39 4.86 14.0 2.4 312.60 308.16 312.40 307.76 6.63 6.0 1.0 313.20 309.21 312.60 308.39 5.13 22.1 10.8 309.00 304.04 308.00 303.94 4.73 22.3 14.5 309.00 304.12 309.00 304.04 3.26 22.8 18.2 308.00 304.11 309.00 304.12 2.48 12.4 7.5 309.00 305.37 308.00 304.58 4.95 8.2 3.2 309.00 305.69 309.00 305.42 6.00 6.6 2.9 309.00 306.02 309.00 305.69 4.44 Design Excess UpSt UpSt On St On St Capacity Capacity Ground HGL Ground HGL V100 Elev. Elev. Elev. Elev. cfs cfs ft ft ft ft ft/s 68.9 7.4 308.00 304.74 308.00 304.09 7.94 69.8 8.2 308.60 304.94 308.00 304.68 8.01 11.0 1.5 309.00 305.57 308.60 304.94 5.02 11.1 2.8 309.00 305.78 309.00 305.57 5.04 48.8 3.0 309.25 305.30 308.60 304.94 6.08 4.9 2.0 309.00 305.92 309.25 305.38 5.57 48.4 3.8 311.10 306.55 309.25 305.30 5.99 29.6 -9.1 312.00 307.30 311.10 306.86 8.79 25.1 -7.6 311.83 308.04 312.00 307.30 6.96 24.2 -1.1 312.40 308.46 311.83 308.04 5.16 14.0 -1.7 312.60 308.89 312.40 308.46 6.64 6.0 -0.8 313.20 309.93 312.60 308.89 5.12 22.1 6.7 309.00 304.22 308.00 304.09 5.26 22.3 11.7 309.00 304.25 309.00 304.22 3.50 22.8 16.5 308.00 304.24 309.00 304.25 2.72 12.4 5.7 309.00 305.50 308.00 304.72 5.35 8.2 1.5 309.00 305.83 309.00 305.58 6.54 6.6 1.6 309.00 306.15 309.00 305.83 4.97 -
Existing
Ponds
El
E2
E3
E4
ES
E6
E7
EB
E9
ElO
El 1
E1 2
El3
El4
E IS
El6
El7
El8
El9
E20
E21
E22
E23
E24
E2S
E26
E27
E28
E29
E30
E31
E32
E33
E34
E3S
E36
E37
E38
E39
E40
E41
E42
E43
E44
PERIMETER
Ft
289
299
288
3Sl
379
262
260
2S9
2S9
223
21 1
214
213
214
204
212
216
216
216
392
468
391
466
387
474
401
491
386
487
22S
223
223
391
131
131
136
138
1S9
1Sl
398
397
498
47S
Exhibit F
The Barracks Subdivision
Existing Pond Storage Computation
AREA Top of Berm WATER ELEV
SF Ac Ft Ft
8603 0.20 311.00 310.98
3211 0.07 312.89 310.78
4087 0.09 312.38 311.46
3768 0.09 312.97 311.61
Sl22 0.12 314.S4 312.98
7432 0.17 313.34 312.S9
332S 0.08 313.SO 313.00
3269 0.08 313 .00 312.SO
328S 0.08 312.SO 312.00
3301 0.08 312.SO 312.00
2679 0.06 312.10 310.BS
1431 0.03 311.90 310.69
lSOO 0.03 312.00 310.6S
1466 0.03 312.03 310.63
1473 0.03 312.02 310.96
1417 0.03 311.50 310.70
14SS 0.03 311.49 310.43
1S20 0.03 311.62 310.3S
1494 0.03 311.86 31 O.S3
1497 0.03 312.28 311.11
83S3 0.19 310.20 309.03
10130 0.23 312.07 310.67
83S7 0.19 309.80 308.69
10148 0.23 311.12 309.89
8000 0.18 309.22 308.43
10S30 0.24 310.42 309.SO
8786 0.20 308.42 307.64
11894 0.27 310.01 308.62
7931 0.18 308.82 306.46
114S9 0.26 308.99 307.94
1S29 0.04 309.34 308.19
1S21 0.03 309.30 307.82
1473 0.03 308.00 306.4S
8284 0.19 307.91 30S.82
844 0.02 308.40 307.06
843 0.02 308.39 307.43
904 0.02 308.30 307.60
943 0.02 308.30 307.74
1218 0.03 308.4S 307.68
1237 0.03 308.4S 307.SS
8603 0.20 307.SO 30S .80
83SS 0.19 307.9S 306.11
12S44 0.29 308.lS 306.10
10648 0.24 308.29 306.87
Total Area 207265 4.76
Average Storage Depth (ft) 6.2114.76 = 1.31 feet
15.66 inches
DIFF Volume
Ft CF Ac-Ft
0.02 172 0.004
2.11 6776 O.IS6
0.92 3760 0.086
1.36 Sl24 0.118
1.56 7991 0.183
0.7S SS74 0.128
O.SO 1662 0.038
o.so 163S 0.038
o.so 1642 0.038
o.so 16Sl 0.038
l.2S 3349 0.077
1.21 1731 0.040
1.3S 202S 0.046
1.40 20S 2 0.047
1.06 1S61 0.036
0.80 1134 0.026
1.06 1S43 0.03S
1.27 1930 0.044
1.33 1987 0.046
1.17 17Sl 0.040
1.17 9773 0.224
1.40 14 182 0.326
1.11 9276 0.213
1.23 12482 0.287
0.79 6320 0.14S
0.92 9688 0.222
0.78 68S3 0.1S7
1.39 16S33 0.380
2.36 18717 0.430
1.0S 12032 0.276
1.1 S 17S9 0.040
1.48 22Sl O.OS2
I.SS 2283 O.OS2
2.09 173 13 0.397
1.34 1131 0.026
0.96 809 0.019
0.70 633 0.QJS
O.S6 S28 0.012
0.77 93 8 0.022
0.90 1113 0.026
1.70 1462S 0.336
1.84 1S373 0.3S3
2.0S 2S71S O.S90
1.42 1S121 0.347
270496 6.21
Drainage Area
100
101
102A
1028
103
104
Drainage Area
600
601
603
604
The Lag Method:
L = t o.s (S+l)°-7
(1900)Y0•5
s = 1000 -10
CN
Tc= 5/3*(L)
Exhibit G
The Barracks Subdivision
Lag Time Calculations
Pre-Development Conditions
e y
CN s Tc
(feet) (%) (hrs)
1577 1.3 75 3.33 0.786
11 03 0.9 98 0.20 0.285
944 1.5 87 1.49 0.328
935 1.1 84 1.90 0.426
1927 0.8 84 1.90 0.890
1077 1.4 75 3.33 0.553
Post-Development Conditions
e y CN (feet) (%)
1755 1.0 75
1606 0.9 91
2307 0.9 84
1077 1.5 75
where: L = ti.me lag, hours
C = hydraulic length, feet
S = maxi.mum retention
Y =slope, percent
where: S = maximum retention
CN = Curve Number
where: L = ti.me lag, hours
T0 =ti.me of concentration, hours
s Tc
(hrs)
3.33 0.952
0.99 0.539
1.90 0.951
3.33 0.535
Elev.
Change
20
10
14
10
15
15
Elev.
Change
18
15
21
16
Lag Lag Slope (hrs) (min)
1.27 0.472 28.303
0.91 0.171 10.261
1.48 0.197 11 .794
1.07 0.256 15.333
0.78 0.534 32.054
1.39 0.332 19.907
Slope Lag Lag
(hrs) (min)
1.03 0.571 34.284
0.93 0.323 19.403
0.91 0.571 34.232
1.49 0.321 19.275
Exhibit H
HEC-HMS Output Files
Pre-Development Conditions
for 2, 10, 25, 50 and 100 yr Design Storms
Project: Rock Prairie Townhomes Simulation Run : Pre - 2
Start of Run : 01 Jan2007, 00 :00 Basin Model: Pre Dev -1980 to 200f
End of Run : 02Jan2007, 00 :05 Meteorologic Model: 2 yr
Compute Time: 14Aug2008, 11 : 17:32 Control Specifications: 24 hr duration
Volume Units: IN
Hydro logic Drainage Area Peak Discharge Time of Peak Volume
Element (Ml2) (CFS) (IN)
DA 100 0.0110000 9.2 01Jan2007, 12:30 2.57
DA 101 Pnd 0.0074375 0.0 01 Jan2007, 00:00 0.00
DA 101 Srfc 0.0074844 0.0 01 Jan2007, 00:00 0.00
DA 102A 0.0028906 4.8 01Jan2007, 12:15 3.82
DA102B 0.0049531 7.3 01 Jan2007, 12: 15 3.66
DA 103 0.0216093 23.2 01 Jan2007, 12:35 3.65
DA 104 0.0239375 21 .5 01 Jan2007, 12:25 2.28
Jct 1 0.0227656 12.1 01 Jan2007, 12: 15 1.28
Jct 2 0.0455468 38.6 01 Jan2007, 12:35 2.93
Outfall 0.0793124 55.3 01 Jan2007, 12:30 2.41
Road X-ing 0.0239375 15.6 01Jan2007, 12:40 2.28
Project: Rock Prairie Townhomes Simulation Run : Pre -10
Start of Run: 01Jan2001 , 00:00 Basin Model: Pre Dev -1980 to 2008
End of Run : 02Jan2001, 00 :05 Meteorologic Model: 10 yr
Compute Time: 19Jul2008, 12:44:36 Control Specifications: 24 hr duration
Volume Units: IN
Hydrologic Drainage Area Peak Discharge Time of Peak Volume
Element (Ml2) (CFS) (IN)
DA 100 0.0110000 18.3 01Jan2001 , 12:30 5.07
DA 101 Pnd 0.0074375 0.0 01 Jan2001 , 00:00 0.00
DA 101 Srfc 0.0074844 7.0 01Jan2001 , 12:30 2.73
DA 102A 0.0028906 8.3 01 Jan2001 , 12: 15 6.65
DA102B 0.0049531 12.9 01 Jan2001, 12: 15 6.44
DA 103 0.0216093 40.7 01Jan2001 , 12:35 6.42
DA 104 0.0239375 45.6 01 Jan2001 , 12:20 4.77
Jct 1 0.0227656 23.0 01 Jan2001 , 12:25 3.14
Jct 2 0.0455468 77.9 01 Jan2001 , 12:35 5.55
Outfall 0.0793124 114.4 01 Jan2001 , 12:35 4.80
Road X-ing 0.0239375 37.2 01 Jan2001 , 12:35 4.77
Project: Rock Prairie Townhomes Simulation Run : Pre -25
Start of Run : 01 Jan2001 , 00 :00 Basin Model: Pre Dev -1980 to 2008
End of Run : 02Jan2001 , 00 :05 Meteorologic Model : 25 yr
Compute Time: 19Jul2008, 12:44:45 Control Specifications : 24 hr duration
Volume Units: IN
Hydro logic Drainage Area Peak Discharge Time of Peak Volume
Element (Ml2) (CFS) (IN)
DA 100 0.0110000 21 .6 01 Jan2001 , 12:30 5.98
DA 101 Pnd 0.0074375 0.0 01 Jan2001 , 00:00 0.00
DA 101 Srfc 0.0074844 12.6 01Jan2001 , 12:25 3.73
DA 102A 0.0028906 9.5 01 Jan2001 , 12: 15 7.64
DA102B 0.0049531 14.8 01 Jan2001, 12: 15 7.42
DA 103 0.0216093 46.8 01Jan2001 , 12:35 7.39
DA 104 0.0239375 54.3 01Jan2001 , 12:20 5.68
Jct 1 0.0227656 35.4 01 Jan2001 , 12:20 3.81
Jct 2 0.0455468 95.4 01Jan2001 , 12:30 6.49
Outfall 0.0793124 144.8 01 Jan2001 , 12:30 5.65
Road X-ing 0.0239375 49.4 01 Jan2001, 12:30 5.68
Project: Rock Prairie Townhomes Simulation Run : Pre -50
Start of Run : 01 Jan2001 , 00 :00 Basin Model: Pre Dev -1980 to 2008
End of Run: 02Jan2001 , 00 :05 Meteorologic Model: 50 yr
Compute Time: 19Jul2008, 12:44:50 Control Specifications: 24 hr duration
Volume Units: IN
Hydro logic Drainage Area Peak Discharge Time of Peak Volume
Element (Ml2) (CFS) (IN )
DA 100 0.0110000 26.2 01Jan2001 , 12:30 7.27
DA 101 Pnd 0.0074375 0.0 01 Jan2001 , 00:00 0.00
DA 101 Srfc 0.0074844 22.2 01Jan2001 , 12:15 5.13
DA 102A 0.0028906 11 .2 01Jan2001, 12:15 9.02
DA102B 0.0049531 17.5 01 Jan2001 , 12: 15 8.79
DA 103 0.0216093 55.4 01 Jan2001 , 12:35 8.76
DA 104 0.0239375 66 .5 01Jan2001 , 12:20 6.97
Jct 1 0.0227656 51 .0 01 Jan2001, 12: 15 4.74
Jct 2 0.0455468 117.1 01 Jan2001, 12:30 7.82
Outfall 0.0793124 180.5 01 Jan2001 , 12:25 6.86
Road X-ing 0.0239375 62 .9 01 Jan2001 , 12:25 6.97
Project: Rock Prairie Townhomes Simulation Run : Pre -100
Start of Run : 01 Jan2001 , 00 :00 Basin Model: Pre Dev -1980 to 2008
End of Run: 02Jan2001, 00:05 Meteorologic Model: 100 yr
Compute Time: 19Jul2008, 12:34:53 Control Specifications: 24 hr duration
Volume Units: IN
Hydrologic Drainage Area Peak Discharge Time of Peak Volume
Element (Ml2) (CFS) (IN)
DA 100 0.0110000 30.2 01 Jan2001 , 12:30 8.39
DA 101 Pnd 0.0074375 0.0 01 Jan2001 , 00:00 0.00
DA 101 Srfc 0.0074844 30.4 01 Jan2001, 12: 15 6.33
DA 102A 0.0028906 12.7 01Jan2001, 12:15 10.21
DA102B 0.0049531 19.8 01Jan2001 , 12:15 9.97
DA 103 0.0216093 62.7 01 Jan2001 , 12:35 9.93
DA 104 0.0239375 77.0 01 Jan2001 , 12:20 8.10
Jct 1 0.0227656 62.8 01 Jan2001 , 12: 15 5.54
Jct 2 0.0455468 134.4 01 Jan2001 , 12:30 8.97
Outfall 0.0793124 210.2 01 Jan2001, 12:25 7.91
Road X-i ng 0.0239375 75.3 01 Jan2001 , 12:25 8.10
Exhibit I
HEC-HMS Output Files
Post-Development Conditions
for 2, 10, 25, 50 and 100 yr Design Storms
Project: Rock Prai rie Townhomes Simulation Run : Post 2 yr
Start of Run : 01 Jan2008, 00:00 Basin Model: Post Dev 6
End of Run : 02Jan2008, 00:05 Meteorologic Model: 2 yr
Compute Time: 13Aug2008, 16:50:55 Control Specifications : 24 hr duration
Volume Units: IN
Hydrologic Drainage Area Peak Discharge Time of Peak Vol um e
Element (Ml2) (CFS) (IN)
DA 600 0.010811 6 6.8 01 Jan2008, 12:40 2.03
DA 601 0.0214688 32.4 01 Jan2008, 12:20 4.14
DA603 0.0232344 24.1 01 Jan2008, 12:35 3.64
DA604 0.0239375 21 .5 01 Jan2008, 12:25 2.28
Det Pond 6 0.0471719 25.1 01Jan2008, 13:10 2.92
Outfall 0.0794523 52.9 01 Jan2008, 12:25 3.13
Road X-ing 0.0239375 15.6 01 Jan2008, 12:40 2.28
Project : Rock Prairie Townhomes Simulation Run : Post 2 yr Reservoir: Det Pond 6
Start of Run :
End of Run:
Compute Time :
Computed Results
Peak lnflo1.11J :
Pe al< 0 utfl 01A1 :
Tota I I ritl Oll'•.1 :
Tota I [I utfl Ol•'t.I :
01 Jan2008, 00:00
02Jan2008, 00:05
13Aug2008, 16:50:55
Volume Units : IN
Basin Model :
Meteorologic Model :
Control Specifications :
:~:9 .Ci (CFS) Date/Time of Peak lnflo1.11.1 :
25. ·1 (C FS)
2 .!;15 (IN)
2 .92 (IN)
Date/Time of F' e al< 0 utfl 01.11.1 :
Peak :3tora !~e :
Peak Elevation :
Post Dev 6
2 yr
24 hr duration
0 ·1Jan200:3, ·12 :35
01Jan200:::, ·1:::::·10
·1.7 (.A.C-FT)
:;:og .::: (FT)
Project: Rock Prairie Townhomes Simulation Run: Post 10 yr
Start of Run: 01 Jan2008, 00:00 Basin Model: Post Dev 6
End of Run : 02Jan2008, 00:05 Meteorologic Model : 10 yr
Compute Time: 13Aug2008, 16:50:45 Control Specifications: 24 hr duration
Volume Units: IN
Hydrologic Drainage Area Peak Discharge Time of Peak Volume
Element (Ml2) (CFS) (IN)
DA 600 0.0108116 15.2 01 Jan2008, 12:40 4.46
DA 601 0.0214688 54.4 01 Jan2008, 12:20 7.00
DA603 0.0232344 42.4 01 Jan2008, 12:35 6.42
DA604 0.0239375 45 .6 01 Jan2008, 12:20 4.77
Det Pond 6 0.0471719 65 .7 01 Jan2008, 12:45 5.53
Outfall 0.0794523 110.0 01Jan2008, 12:40 5.78
Road X-ing 0.0239375 37 .2 01 Jan2008, 12:35 4.77
Project : Rock Prairie Town homes Simulation Run : Post 10 yr Reservoir: Det Pond 6
Start of Run :
End of Run :
Compute Time .:
Computed Results
01 Jan2008, 00:00
02Jan2008, 00:05
13Aug2008, 16:50:45
Volume Units : IN
Basin Model :
Meteorologic Model :
Control Specifications :
Post Dev 6
10 yr
24 hr duration
Peak I nfl ol•1.1 : 7 !;1 .6 (CFS) Date/Time of Pea~: lnflo1.11.1 : D·1Jan200:3, 12 ::~:5
Peak 0 utfl 01.11.1 : ti5. 7 (CFS) Date/Time of Pea~: OutfJ.:11.11.1 : 1)·1Jan2D0:3, 12:45
Tota I I nfl •:11,11) : 5 .5:3 (IN) Peak :,:;tora9e : 2 .:3 (.A.C-FT)
Tota I 0 utfl 01.1\1 : 5 .5:3 (IN) Peak Elevation : :3"10 .7 (FT)
Project: Rock Prairie Townhomes Simulation Run: Post 25 yr
Start of Run : 01 Jan2008, 00:00 Basin Model: Post Dev 6
End of Run: 02Jan2008, 00:05 Meteorologic Model: 25 yr
Compute Time: 13Aug2008, 16:50:50 Control Specifications: 24 hr duration
Volume Units: IN
Hydrologic Drainage Area Peak Discharge Time of Peak Volume
Element (Ml2) (CFS) (IN)
DA600 0.0108116 18.1 01 Jan2008, 12:40 5.36
DA 601 0.0214688 62.0 01Jan2008, 12:20 8.00
DA603 0.0232344 48.8 01 Jan2008, 12:35 7.39
DA604 0.0239375 54.3 01 Jan2008, 12:20 5.68
Det Pond 6 0.0471719 80.7 01 Jan2008, 12:45 6.46
Outfall 0.0794523 137.4 01 Jan2008, 12:40 6.73
Road X-ing 0.0239375 49.4 01 Jan2008, 12:30 5.68
Project : Rock Prairie Townhomes Simulation Run : Post 25 yr Reservoir: Det Pond 6
Start of Run :
End of Run :
Compute Time :
Computed Results
01 Jan2008, 00 :00
02Jan2008, 00 :05
13Aug2008, 16:50:50
Volume Units : IN
Basin Model :
Meteorologic Model :
Control Specifications :
Post Dev 6
25 yr
24 hr duration
Peak I rdl 0111.1 : 9ti .5 (CFS) D atelT i me of Peak: I nfl 01.fl.I : 0 ·1 J a n2008, ·12 :~:[I
Peak: Outflo1A1 : :::0.7 (CFS) Date/Time of Peak: Outflo1/1.1 : 01Jan2008, ·12:45
Total lnfli:11.11.1 : ti.52 (IN) Peak: :::tora!~e : 2.5 (.A.C-FT)
Total Outfli:11fl.I : ti.4Ci (IN) Peak Elev ation : 31 ·1.0 (FT)
Project: Rock Prairie Townhomes Simulation Run : Post 50 yr
Start of Run : 01 Jan2008, 00 :00 Basin Model: Post Dev 6
End of Run : 02Jan2008, 00 :05 Meteorologic Model: 50 yr
Compute Time: 13Aug2008, 16:50 :59 Control Specifications: 24 hr duration
Volume Units: IN
Hydrologic Drainage Area Peak Discharge Time of Peak Volume
Element (Ml2) (CFS) (IN)
DA 600 0.0108116 22.3 01Jan2008, 12:40 6.64
DA 601 0.0214688 72.6 01 Jan2008, 12:20 9.39
DA 603 0.0232344 57.7 01 Jan2008, 12:35 8.75
DA604 0.0239375 66.5 01 Jan2008, 12:20 6.97
Det Pond 6 0.0471719 90.5 01Jan2008, 12:50 7.78
Outfall 0.0794523 166.4 01 Jan2008, 12:30 8.06
Road X-ing 0.0239375 62.9 01 Jan2008, 12:25 6.97
Project : Rock Prairie Townhomes Simulation Run : Post 50 yr Reservoir: Det Pond 6
Start of Run : 01 Jan2008, 00:00
End of Run : 02Jan2008, 00:05
Basin Model :
Meteorologic Model :
Post Dev 6
50 yr
Compute Time : 13Aug2008, 16 :50 :59 Control Specifications : 24 hr duration
Volume Units : IN
Computed Results
Pe al< I nfl 01.1\1 : ·1 ·rn .4 (CF :3) [) atelT i me of Pe alt: I nfl 01/1.1 : 0 ·1 J a n200:::, ·12 ::;:o
p e alt: D uttl C•IN : !;10 .5 (CFS) Date/Time i:rf Peal<: Dutflo1f1J : O·Uan200B, ·12 :50
Tota I I rifl 1;.1..-..1 : 7 .:::5 (I t{1 F' e alt: :::tor a!~ e : :~: .0 (.A.C-FT)
Tota I D utfli:1111.1 : 7. 7:?. (IN) F'ea~: Elev ation : :;:·1·1.7 (FT)
Project: Rock Prairie Townhomes Simulation Run: Post 100 yr
Start of Run : 01Jan2008, 00:00
End of Run : 02Jan2008, 00:05
Compute Time: 14Aug2008, 16:43:37
Volume Units: IN
Basin Model: Post Dev 6
Meteorologic Model: 100 yr
Control Specifications: 24 hr duration
Hydrologic Drainage Area Peak Discharge Time of Peak Volume
Element (Ml2) (CFS) (IN)
DA600 0.0108116 26.0 01 Jan2008, 12:35 7.75
DA 601 0.0214688 81 .7 01 Jan2008, 12:20 10.58
DA603 0.0232344 65.3 01 Jan2008, 12:35 9.93
DA604 0.0239375 77.0 01 Jan2008, 12:20 8.10
Det Pond 6 0.0471719 99.5 01 Jan2008, 12:50 8.92
Outfall 0.0794523 184.8 01 Jan2008, 12:30 9.21
Road X-ing 0.0239375 75.3 01 Jan2008, 12:25 8.10
Project : Rock Prairie Town homes Simulation Run : Post 100 yr Reservoir: Det Pond 6
Start of Run : 01 Jan2008, 00:00 Basin Model :
End of Run : 02Jan2008, 00:05 Meteorologic Model :
Compute Time : 14Aug2008, 16:43:37 Control Specifications :
Corrputed Results
Peak Inflow:
Peak Outflow :
Tota I Inflow :
Total Outflow:
Volume Units : IN
135.9 (CFS)
99.5 (CFS)
9.00 (IN)
8.92 (IN)
Date/Time of Peak Inflow:
Date/Time of Peak Outflow:
Peak Storage :
Peak EI ev ati on :
Post Dev 6
100 yr
24 hr duration
01Jan2008, 12:30
01Jan2008, 12:50
3.5 (AC-FT)
312.4 (FT)
Project: Rock Prairie Town homes Simulation Run : Post 100 yr Emerg Spillway
Start of Run: 01 Jan2001 , 00:00 Basin Model: Post Dev 6 w/ blocked
End of Run : 02Jan2001 , 00:05 Meteorologic Model : 100 yr
Compute Time: 13Aug2008, 11 :46 :08 Control Specifications: 24 hr duration
Volume Units: IN
Hydrologic Drainage Area Peak Discharge Time of Peak Volume
Element (Ml2) (CFS) (IN)
DA600 0.0108116 26.0 01 Jan2001 , 12:35 7.75
DA 601 0.0214688 81 .7 01Jan2001 , 12:20 10.58
DA603 0.0232344 65.3 01Jan2001 , 12:35 9.93
DA604 0.0239375 77.0 01Jan2001 , 12:20 8.10
Det Pond 6 0.0471719 135.1 01Jan2001 , 12:30 9.00
Outfall 0.0794523 231 .6 01Jan2001 , 12:30 9.26
Road X-ing 0.0239375 75.3 01 Jan2001 , 12:25 8.10
Project : Rock Prairie Townhomes Simulation Run : Post 100 yr Emerg Spillway Reservoir: Del Pond 6
Start of Run : 01 Jan2001 , 00:00 Basin Model : Post Dev 6 w/ blocked outlet
End of Run : 02Jan2001 , 00:05 Meteorologic Model : 100 yr
Compute Time : 13Aug2008, 11 :46 :08 Control Specifications : 24 hr duration
Volume Units : IN
Computed Results
Peak lnf1 01.1\I: ·1:::5.Q (CFS)
Peak Outflow : 1:::5 :1 (CFS)
Total lnflo~\1 : 9.00 (IN)
Tota I Cl 1Jtfl 01.11.1 : !~ .00 (IN)
Date/Time of Peak lnflo1N :
[i ate/Time i:1f Peak Cl utfl 01.11.1 :
Peak ::;fora!~e :
Peak Elevation :
O·Uan2001 , ·12::30
01.lan200·1 , ·12 :30
:3 .9 (AC-FT)
312.!~ (FT)
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
The Cities of Bryan and College Station both require storm drainage design to follow these
Unified Stormwater Design Guidelines. Paragraph C2 of Section Ill (Administration) requires
submittal of a drainage report in support of the drainage plan (stormwater management plan)
proposed in connection with land development projects, both site projects and subdivisions.
That report may be submitted as a traditional prose report, complete with applicable maps,
graphs, tables and drawings, or it may take the form of a "Technical Design Summary". The
format and content for such a summary report shall be in substantial conformance with the
description in this Appendix to those Guidelines. In either format the report must answer the
questions (affirmative or negative) and provide, at minimum, the information prescribed in the
"Technical Design Summary" in this Appendix.
The Stormwater Management Technical Design Summary Report shall include several parts
as listed below. The information called for in each part must be provided as applicable. In
addition to the requirements for the Executive Summary, this Appendix includes several
pages detailing the requirements for a Technical Design Summary Report as forms to be
completed. These are provided so that they may be copied and completed or scanned and
digitized. In addition, electronic versions of the report forms may be obtained from the City.
Requirements for the means (medium) of submittal are the same as for a conventional report
as detailed in Section Ill of these Guidelines.
Note: Part 1 -Executive Summary must accompany any drainage report
required to be provided in connection with any land development project,
regardless of the format chosen for said report.
Note: Parts 2 through 6 are to be provided via the forms provided in this
Appendix. Brief statements should be included in the forms as requested,
but additional information should be attached as necessary.
Part 1 -Executive Summary Report
Part 2 -Project Administration
Part 3 -Project Characteristics
Part 4 -Drainage Concept and Design Parameters
Part 5 -Plans and Specifications
Part 6 -Conclusions and Attestation
STORMWATER MANAGEMENT TECHNICAL DESIGN SUMMARY REPORT
Part 1 -Executive Summary
This is to be a brief prose report that must address each of the seven areas listed below.
Ideally it will include one or more paragraphs about each item.
1. Name, address, and contact information of the engineer submitting the report, and
of the land owner and developer (or applicant if not the owner or developer). The
date of submittal should also be included.
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 1 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
2. Identification of the size and general nature of the proposed project, including any
proposed project phases. This paragraph should also include reference to
applications that are in process with either City: plat(s), site plans, zoning requests,
or clearing/grading permits, as well as reference to any application numbers or
codes assigned by the City to such request.
3. The location of the project should be described. This should identify the Named
Regulatory Watershed(s) in which it is located, how the entire project area is
situated therein , whether the property straddles a watershed or basin divide, the
approximate acreage in each basin, and whether its position in the Watershed
dictates use of detention design . The approximate proportion of the property in the
city limits and within the ET J is to be identified, including whether the property
straddles city jurisdictional lines. If any portion of the property is in floodplains as
described in Flood Insurance Rate Maps published by FEMA that should .be
disclosed.
4. The hydrologic characteristics of the property are to be described in broad terms :
existing land cover; how and where stormwater drains to and from neighboring
properties; ponds or wetland areas that tend to detain or store stormwater; existing
creeks, channels, and swales crossing or serving the property; all existing drainage
easements (or ROW) on the property, or on neighboring properties if they service
runoff to or from the property.
5. The general plan for managing stormwater in the entire project area must be
outlined to include the approximate size, and extent of use, of any of the following
features: storm drains coupled with streets; detention I retention facilities; buried
conveyance conduit independent of streets; swales or channels; bridges or culverts;
outfalls to principal watercourses or their tributaries ; and treatment(s) of existing
watercourses. Also, any plans for reclaiming land within floodplain areas must be
outlined.
6. Coordination and permitting of stormwater matters must be addressed. This is to
include any specialized coordination that has occurred or is planned with other
entities (local, state, or federal). This may include agencies such as Brazos County
government, the Brazos River Authority, the Texas A&M University System, the
Texas Department of Transportation, the Texas Commission for Environmental
Quality, the US Army Corps of Engineers, the US Environmental Protection Agency,
et al. Mention must be made of any permits, agreements, or understandings that
pertain to the project.
7. Reference is to be made to the full drainage report (or the Technical Design
Summary Report) which the executive summary represents. The principal
elements of the main report (and its length), including any maps, drawings or
construction documents, should be itemized. An example statement might be:
"One J....S -page drainage report dated 7/z1 /oB, one set of
construction drawings ( 2..0 sheets) dated 7 /2.1 /0$ , and a
___ -page specifications document dated r comprise
the drainage report for this project."
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 2 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 2 -Project Administration I Start (Page 2.1)
Engineering and Design Professionals Information . .· ... ..
..
Engi~eering Firm Name and Address: l Jurisdiction
City: Bryan c I V1 . I !Jev, ( r m,,,,/, -I ol
f IJ ~o ~ /f12 ~allege Station
CoJIPe\e Sia/~/) . I~ 778'12
Date of ubkittal:
7 21 oB
Lead Englneer's Name and Contact lnfo.(phone, e-mail, fax): Other:
k'enf J az{J, 7G9-77l/S
Supporting Engineering I Consulting Firm (s): Other contacts:
..... Developer I Owner I Applicant Information ········ .... . .... /." : . .· :
Developer I Applicant Name and Ad~ress: Phone and e-mail: Gre<>1) /'r e:;.;~, ·e . ..1. ,,,'<~ s~.~ ">I L, c
'f ~ 10 Ca:d?:-fe_ .iJr1've C,.CfO-72-:JO
G//e.;-c' s./-... ,~ ... , !¥-77'3•1 ,-
Propeffy Owner(s) if not Developer I Applicant (& address): Phone and e-mail:
.... . . ·•· J ;_> . Project Identification :
.'." .iL •· •;...:. . ... . . .. , . . ,. ... ..::
Development Name: 77?e /2.c rr <'c/c c; 5:., t )t'v' 0
5' I~ ,,
Is subject property a site project, a single-phase subdivision, or part of a multi-phase subdivision?
/Y)!l./t,· If multi-phase, subject property is phase L of 2-
Legal description of subject property (phase) or Project Area:
(see Section II , Paragraph B-3a)
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 Lo~atir of Pr~ject Are_a, or subjf ct pro~.erty (phase): /flc« c/ 01"1 f?o ck t;~ :, ·~' ,Ir 1<r m ; WFS o Lu,.f//,or ,
r"' 1 r : e. /? ).
In City Limits? Extraterritorial Jurisdiction (acreage):
Bryan : acres. Bryan: College Station:
College Station: Is. '1 acres. Acreage Outside ET J:
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 3 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 2 -Project Administration I Continued (page 2.2)
"' •· ··Project lderitificatio11 (continued) .. .
Roadways abutting or within Project Area or Abutting tracts, platted land, or built
subject property: developments:
/?ocJ Pr ( ' "C(I r1 " ~cl UJ, '/(•6,VJe;le ~t), ~I '5,,9~1
Named Regulatory Watercourse(s) & Watershed(s): Tributary Basin(s):
/Jee G-eelc Un lc11 pw,, fr,~" /v•7
. . . . · -. -·. ··· .. ,. . . ...
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 SubjectProperty (or Phase) .. •< ..
Zoning Type: R-t ~r Proposed? Case Code:
Case Date Status:
Zoning Type: Existing or Proposed? Case Code:
Case Date Status:
Stormwater ManagemenlPlanning Fo; Project or' Subje~t Property (or Ph~se) ..
,._, '"-""" ,_.,_.... .. . : ,,. ·:· -. .. . -':.,.. .
Planning Conference(s) & Date(s): Participants:
fo (3/oB
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
Effective February 2007
Page 4 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 2 -Project Administration I Continued (page 2.3)
cc'··· .-. .. ; ···-·.· '>' ..... '"· 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.
Coordination
With Other
Departments of
Jurisdiction
City (Bryan or
Dept. Contact: Date: Subject:
College Station) 1-------+--------r-----+--------------"j
Coordination With
Non-jurisdiction
City Needed?
Summarize need(s) & actions taken (include contacts & dates):
Yes __ No V
Coordination with
Brazos County
Needed?
Summarize need(s) & actions taken (include contacts & dates):
Yes __ No V
Coordination with
TxDOT Needed?
Summarize need(s) & actions taken (include contacts & dates):
Yes __ No V
Coordination with
TAMUS Needed?
Summarize need(s) & actions taken (include contacts & dates):
Yes __ No v
. ....•.. Permits For F>.roject()r ~ubject.~.r~IJerty (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
US Army Crops of
Engineers
No~ Yes_
US Environmental
Protection Agency
No V Yes_
Permitted or
Approved?
Texas Commission on _.,
Environmental Quality 1) 0 J.
No __ Yes V .,.,II
Brazos River
Authority
No V Yes_
STORMWATER DESIGN GUIDELINES
Effective February 2007
Status of Actions (include dates)
Page 5 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 3 -Pro~ertv Characteristics I Start (Page 3.1)
· .. ···· .. ·. Nature and Scope of proposed Work , ? ..
..
Existing: Land proposed for development currently used, including extent of impervious cover?
Site __ Redevelopment of one platted lot, or two or more adjoining platted lots.
Development __ 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 lo& lofs
Pro12osed
Project
Is any work planned on land that is not platted If yes, explain:
or on land for which platting is not pending?
V---No Yes --
.. .,;,,
.. FEMA Floodplains .. · ..........
Is any part of subject property abutting a Named Regulatory Watercourse I N ~ y
(Section II, Paragraph B1) or a tributary thereof? 0 --es __
Is any part of subject property in floodplain 1 No _k:::::_ Yes Rate Map area of a FEMA-regulated watercourse? --
Encroachment(s) Encroachment purpose(s): __ Building site(s) __ Road crossing(s) into Floodplain
areas planned? __ Utility crossing(s) __ Other (explain):
No V
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.
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 6 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 3 -Property Characteristics I 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 ~1--pl_a_n_fo_r_t_he~p_ro_p_e_rty~in_P_a_rt~4-·~~~~~~~~~~~~~~~~~~~~-----1
If property is part of multi-phase project, provide overview of stormwater management plan
for Project Area here. In Part 4 describe how plan for subject property will comply
therfri~~1'0 //' {~r>"I J/~ift' w1'/ f t e_ c;:' ~.;;,-,,/ Qr)~
J i ' I /') / / fl f j ~ -;;, le Lr-./' JI ~ e clrr.~1:ic) ~-4e'f-l:l 1 .-i,-¢. y,,,,,,, -f -fre>1n ~ t
fo ~~ ey.1$-/,:..7 ovi.../:.1! /.J <f~_,~./ j.,,.fe,*//;r.,
Do existing topographic features on subject property store or detain runoff? __ No
Describe them (include approximate size, volume, outfall, model, etc).
~l/ ~ma// ;~/1cJ-S i/Jt-cA /:r tui;fe r J. /,'e:.-c/e f .:,,;,..1 mc/c.Ji
ex,'s/,-,,,j r v.it-f-1_ See cle/--..-,,_/.-, .. ?~.,/""'"/'Ir·~. ~
Any known drainage or flooding problems in areas near subject property? _·_ No
Identify:
__ Yes
Yes
Based on location of study property in a watershed, is Type 1 Detention (flood control) needed?
(see Table B-1 in Appendix B)
L°Detention is required. __ Need must be evaluated. __ Detention not required.
If the need for
Type 1 Detention
must be evaluated:
What decision has been reached? By whom?
How was determination mage? / H £ C /-/ /JJ S or,6f I 7' s / > o ;J' e aj')J /o >-1
J .Pvi' b/J 111 PI'/+ rlh 1 o-/? COvt cl,· J' ~1-1 s _
I
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 7 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 3 -Property Characteristics I Continued (Page 3.3)
Hydrologic Attributes ()f Subject Property (or Phase) (continued)
Does subject property straddle a Watershed or Basin divide? V°No __ Yes If yes,
describe splits below. In Part 4 describe design concept for handling this.
Watershed or Basin Larger acreage Lesser acreage
Above-Project Areas(Section II, Paragraph 83-a)
Does Project Area (project or phase) receive runoff from upland areas? __ No V Yes
Size(s) of area(s) in acres: 1) 7. O L/ 2) 15. g 3 3) I 6. .3 2..-4)
Flow Characteristics (each instance) (overland sheet, shallow concentrated, recognizable
concentrated section(s),_small creek (non-regulptory}, re_g,ulatory Wate~cours~ or ~ributary); / Generc.fly a ll (~ t!?h"r-/a.1d ~£Jee! -/:10~ lot-I-./ ,.'/.-15 c7rv 0 .I
~~ +J.t 1,,c K /JN,,~. ~ /2 oet~ 01' 1-c A.
Flow determination: Outline hydrologic methods and assumptipns: , A eA
f/£c ;-/!Y>5 .,,:;,~J ::;c5 Cor>re. nvmb.r.-q... )C> Ur11f y 'Jt''r<f'J...
/lJ5 ~· .:s,..cA In ,'/1 ~J 4n/ {'pll,r/., ~ 1 Los·;; /l?< f A;;J -{;v ey..t's{~J /"''v~ s-.
Does storm runoff cjrain from public easements or ROW onto or across subject property?
__ No __ V_Y Ye es If yes , describe facilities in easement or ROW:
/?Pc /c ffa1r•~ Koo / C?l /-c-/.e> th1~i CJ !v,.r/
Are changes in runoff characteristics subject to yl;lan~e in fut~re? ~xplain ,
/-and v><?§ w 1 '// cJ1qv15e , L~I ,·j. ofefcul.~,,, 1-;' ~etvr .-ee/ cu1t?r-.
/-he>< ~-c>v.e l/"°'~~.-f·; oCC(.)('1 (A~ fol( rt,1:1c {/ ;,-Ao1..• /c/ 11~1 /;,,Cir c-se>
Conveyance Pathways (Section II , Paragraph C2)
Must runoff from study property drain across lowereroperties before reaching a Regulatory
Watercourse or tributary? No ~Yes
Describe length and characteristics of each conveyance pathway(s). Include ownership of
property(ies).
:SJialfow . f~~ L/"'°( 0 / &zc C:e-e L fhr,f 15 °//rox/~~i:y
2000 -{f?t?f /ortJ,
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 8 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 3 -Property Characteristics I Continued (Page 3.4)
Hydrologic Attributes of Subject Property (orPhase) (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)?
~No
Yes
Where runoff must cross lower properties , describe characteristics of abutting lower
property(ies). (Existing watercourses? Easement or Consent aqu ired?)
Pathway T he t r;:;;pr l-7 ~'/FrOf-''1,l~~J tJe cLu11•e ( I~ CU1
Areas 'l('11 _ I.~ /J V t th a f;."..._; >CQ 11~,-~J f /-e:-e-s. Lo11~;,,-;,f
Nearby
J,us-£.,.en qf,_,,>· ... d £, t/,e //,M/1,J re /.,.ct5c.
Describe any built or improved drainage facilities existing near the property (culverts,
bridges, lined channels, buried conduit, swales, detention ponds, etc).
11,e ,,vtf /I /;, -1 ),_ wJ!""''TI'
ah._, h f h, ~ c /.. q n,, ~ I qn A us~ s /-/
-.
Drainage 1----------------------------------1 Facilities Do any of these have hydrologic or hydraulic influence on proposed stormwater
design? __L_ No __ Yes If yes , explain:
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 9 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 4 -Drainage Conce~t and Design Parameters I 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.
(?Lll1cf/ ~~ Ro e k ~C/f ~ € /(o.,A Pow S ~;evl f; 1 :, f_,
tAe '7"!. r'r-e 10~5,, l I J1 ll r fr(o 5Pp/ /t),,,J. ( 5· l?o
i!J-vr £ d-ev " ~'Y' ~ •• I f &' t~c i +), 5 -!Iott;
Discharge(s) To Lower Property(ies) (Section II, Paragraph E1)
Does project include drainage features (existing or future) proposed to become public via
platting? No ~Yes Separate Instrument? No Yes
Per Guidelines reference above, how will __ Establishing Easements (Scenario 1) runoff be discharged to neighboring c::::---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# )
/) e +-f' VJ /I
1
(}//I f'711 cl -see ~'cc/CJ/VI/ RA l ':'J r~~,f
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)? No V Yes Explain and provide
documentation.
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 10 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 4 -Drainage Concept and Design Parameters J Continued (Page 4.2)
Stormwater Management Concept (continued) · ... ·.· ··.···· .. .
Within Project Area Of Multi-Phase Project
Identify gaining Basins or Watersheds and acres shifting:
Will project result
in shifting runoff
between Basins or ~~~~~~~~~~~~~~~~~~~..,.--~~--:-~-::-~---j
between What design and mitigation is used to compensate for increased runoff
Watersheds? from gaining basin or watershed?
V No
Yes
How will runoff from Project 1. __ With facility(ies) involving other development projects.
Area be mitigated to pre-2. ~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# )
2. For Overall Project Area (type & location of facilities): (Attached Exhibit# )
/Jc:-frnl ~~' /vNA q~d 5f~r "n olro.~ <>7~f-e,,..,,..
3. By phase (or site) project: Describe planned mitigation measures for phases (or sites) in
subsequent questions of this Part.
C'-·
"O Q) ff) c Q) c >-~
0...
ff) c
Cl "Ui
Q) 0 Oz
l~
Q)
-<
Are aquatic echosystems proposed? __ No
project(s)?
__ Yes In which phase(s) or
Are other Best Management Practices for reducing stormwater pollutants proposed?
__ No __ Yes Summarize type of BMP and extent of use:
If design of any runoff-handling facilities deviate from provisions of B-CS Technical
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
Effective February 2007
Page 11 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 4 -Drainage Conce~t and Design Parameters \ Continued (Page 4.3)
.. . Stormwater Management Concept (continued) ....
Within Project Area Of Multi-Phase Project (continued)
Will Project Area include bridge(s) or culvert(s)? __ No~ Yes Identify type and
general s~~e and In waich phase(~ k 18 Co.1 /"er-> 011 o c A , .
/'~t ,.I .,e Ro •. .-/ .J!r C: •l lfi"'l "Ge_
JI< 'v {tV,71 ~-
If detention/retention serves (wi ll serve) overall Project Area, describe how it relates to subject
phase or site project (physical location, conveyance pathway(s), construction sequence):
5(?C"" acCn'7/'P'1r1, ~ l''li,,1r+
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 No, then summarize the difference(s):
Identify whether each of the types of drainage features listed below are included, extent of use,
and general characteristics.
Typical shape? I Surfaces?
<:-· "C (!) II) Steepest side slopes: Usual front slopes: Usual back slopes: II)
:::i (!)
II) >-
(!)
I
..c Flow line slopes: least Typical distance from travelway: g "C typical (Attached Exhibit# )
(!) 0 greatest "C 'Ui z "C f Cll 0 Are longitudinal culvert ends in compliance with 8-CS Standard Specifications? .....
(!) Yes No, then explain: ..... <(
II) At intersections or otherwise, do valley gutters cross arterial or collector streets?
.0 (!) I./ No Yes If yes explain: ::; <:-· >---
u "Ci ..c (!) ..... II) ·~;:: Are valley gutters proposed to cross any street away from an intersection? II) (!)
03 =§ 0 /No __ Yes Explain: (number of locations?) ~ O>Z ti "C
I
(!) c ..... Cll <(
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 12 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 4-Drainage ConceQt and Design Parameters I Continued (Page 4.4)
''" . . . .. , " "" Stormwater Management Concept (continued)
"
Within Or Serving Subject Property (Ph~se, or Site) (continued) ,.....
Gutter line slopes: Least fJ. Hn 3 Usual (?.flu% Greatest c2: 1o '7e c:... '1-'-
Are inlets recessed on arterial and collector streets? Vves --No If "no",
identify where and why.
Will inlets capture 10-year design stormflow to prevent flooding of intersections (arterial
with arterial or collector)? V Yes __ No If no, explain where and why not.
C'-· "O
Q)
Ul Will inlet size and placement prevent exceeding allowable water spread for 10-year ::I
L.. design storm throughout site (or phase)? VYes No If no, explain. Q) ::::: --::I
Cl
-o-c "O
_i.L'Yes co Q) Sag curves: Are inlets placed at low points? No Are inlets and .o 2 --
L.. ·-conduit sized to prevent 100-year stormflow from ponding at greater than 24 inches? ::I -(.) c V" Yes __ No Explain "no" answers. 0 ..c (.) ::::-~
Ul "ID Q) L.. -Ul
Q) Will 100-yr stormflow be contained in combination of ROW and buried conduit on L.. <{ whole length of all streets? ~Yes __ No If no, describe where and why.
Do d~ns 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? V No --Yes Identify length(s) and where
used.
C'-· "O Pipe runs between system I Typical )2LI Q) Ul /DO Longest Ul Q) access points (feet): ::I>-
!vt Are junction boxes used at each bend? V Yes --No If not, explain where
and why.
Ul
c ·-0 ~z "O
I E L.. 0 Are do~eam soffits at or below upstream soffits? Least amount that hydraulic u;
.!!!. Yes __ No __ If not, explain where and why: grade line is below gutter line
(system-wide):
2.98
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 13 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 4-Drainage Concept and Design Parameters I Continued (Page 4.5)
· · .. Stormwater Management Concept (continued) ·.
Within Or Serving Subject Property (Phase, or Site) (continued)
u:;
(!) u c CIJ u; c
~ -o ~E :J L.. -~ .E c .
0 .E ~-~
~ ~ ...... CIJ ~en en (!)
c :Q ·-> ~ e -0 a.
§a:;
0 (!) ...... .s:: Cf) en
(!) -ro L..
CIJ a. (!) en
Describe watercourse(s), or system(s) receiving system discharge(s) below
(include design discharge velocity, and angle between converging flow lines).
~-Watercourse (or system), _velocity, and ~gle?, . t...ri ii //,,{,1.J 1~ /,,. t:;
...J.,11 :,t,,b ~c;-% ve 11 f ;' J.,,,:> .. > 1 . ~for l"1 .· r a 1 • ) .
s·-f1//,.,,i /:..,$,'., fr1 ~1~ +, efl~ri~.1 fAe oH-5;/.,. w-tft.r ut:1r5e,
2) Watercourse (or system), velocity, and angle?
3) Watercourse (or system), velocity, and angle?
For each outfall above, what measures are taken to prevent erosion or scour of
receiving and all facilities at juncture? _ . _ { 1.
1) Rod:: r_i';: rf//J ;'s vY'cl w.J.~ /oh~s-c , .L . ,,,. a"J .Jlt c ,.,
i,U,·t·A s-.Jt -f.'1>,1c:..c ~,,c4 of-/i £t-.tediu,.< ... i,J,~.,, (,,,,{,...,/-;:
2)
c ~ 3)
C'-· en a:> ~ en ...... (!) en >-c ~1
~o en Z :J
i I en
(!)
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):
Flow line ~lope~ (minimum a~d max)mum):_i , I' ' /))q 1~1 f .. 1 vt('d vnf./ ff14f /i•V\.P .
Outfall characteristics for each (velocity, convergent angle, & end treatment).
.< 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
Effective February 2007
Page 14 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 4 -Drainage Conce~t and Design Parameters j Continued (Page 4.6)
Stormwater Management Concept (continued) . ·. .
Within Or Serving Subject Property (Phase, or Site) (continued)
(/)
Are roadside ditches used? V No __ Yes If so, provide the following:
(1) Is 25-year flow contained with 6 inches of freeboard throughout ? __ Yes --No L: ~ Are top of banks separated from road shoulders 2 feet or more? __ Yes --No
0 Are all ditch sections trapezoidal and at least 1.5 feet deep? Yes No (1) ----1:l For any "no" answers provide location(s) and explain: ·u;
1:l Cl]
0 0::
If conduit is beneath a swale, provide the following information (each instance).
Instance 1 Describe general location, approximate length:
(/)
(1) >-
I~ Is 100-year design flow contained in conduit/swale combination? --Yes --No
If "no" explain:
c 0 Cl] z (i) Space for 100-year storm flow? ROW Easement Width vf ~ . ro Swale Surface type, minimum Conduit Type and size, minimum and maximum
c and maximum slopes: slopes, design storm: ~ C'-· 1:l .!!!. 1:l (1) Cl] c >. Inlets Describe how conduit is loaded (from streets/storm drains, inlets by type): c
Cl] c
L: Cl]
(.) .._
c J2
(1) c c. 0 0 :.;::; Access Describe how maintenance access is provided (to swale, into conduit): -Cl] 0 E ::::J .._
.!!! J2 c c (1)
1:l E Instance 2 Describe general location, approximate length: (1) Cl] (/) (/) ::::J
(/) (1)
c 1:l
0 ·:;: Is 100-year design flow contained in conduit/swale combination? Yes No ~ 0 ----.._ If "no" explain: c c.
:0 ... (1) E (1)
0 L: Space for 1 00-year storm flow? ROW Easement Width (.) (/) ... (1) Swale Surface type, minimum Conduit Type and size, minimum and maximum ::::J ... Cl] 1:l .._ and maximum slopes: slopes, design storm: c Cl]
0 c.
(.) (1) --(/) Describe how conduit is loaded (from streets/storm drains, inlets by type): ..!!! c Inlets Cl] .s. ~ (/)
(1) .._
<( Access Describe how maintenance access is provided (to swale, into conduit):
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 15 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 4 -Drainage Concept and Design Parameters I Continued (Page 4. 7)
. .... . ··. ' . . . . . . Stormwater ManagementConcept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
.!: cu
0. E x 0 w .t=
If "yes" provide the following information for each instance:
Instance 1 Describe general location, approximate length, surfacing:
15 IJ) Is 100-year design flow contained in swale? __ Yes __ No Is swale wholly
Q) within drainage ROW? __ Yes __ No Explain "n o" answers:
_; >-I >--------------------------------~ u Access Describe how maintenance access is provide: ~ 0 3z ~,Jf--~~~~~~~~~~~~~~~~~~-----i ...., ~ I Instance 2 Describe general location, approximate length, surfacing:
Q) ·;:::: C'-·
:J IJ)
..0 c
::; Q)
o E
£ 3l ·:;: cu
Q)
IJ) .... ~ 0
cu s ~o = 0::: ~ ,g
..0 :J c..
Is 100-year design flow contained in swale? __ Yes __ No Is swale wholly
within drainage ROW? __ Yes __ No Explain "no" answers:
Access Describe how maintenance access is provided:
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 c.han)J.elized (deepened,
widened, or straightened) or otherwise altered? __ No _~_ v Y•es If only slightly
c-· shaped , see "Swales" in this Part. If creating side banks, provide information below.
"O c r-----------------~----------------1 3l JS! Will design replicate natural channel? V Yes __ No If "no", for each instance
g_ ~ describe section shape & area, flow line slope (min. & max.), surfaces, and 1 DO-year ~ w design flow, and amount of freeboard:
1!3 ~ Instance 1:
c >-11 c.. E o z
Q) c c cu .c
() I
Instance 2:
Instance 3:
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 16 of26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ____ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 4 -Drainage ConceQt and Design Parameters I 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 V Yes
If "yes" provide the information below.
Will small creeks and their floodplains remain undisturbed? __ Yes VNo How
m_:ny disturb~nce _instances? I ldfify e'ch plann,ed location:
J ft/fYle-e/t ~ fy dow1,5fr,.,,,./., " i c. 5rf.:: ·
For each location, describe length and general type of proposed improvement
(including floodplain changes):
See C 011 5 f r v c. /, ~ n (' / 4 n S'
For each location, describe section shape & area, flow line slope (min. & max.),
surfaces, and 100-year design flow.
see c..,n 5Jr v c J1 ~ /l ~kl/>
:a-Q)
::l c ~ Watercourses {and tributaries}: Aside from fringe changes, are Regulatory 0 Watercourses proposed to be altered? ~No Yes Explain below. ~ --Ill c Submit full report describing proposed changes to Regulatory Watercourses. Address
Q) existing and proposed section size and shape, surfaces, alignment, flow line changes, E
Q) length affected, and capacity, and provide full documentation of analysis procedures > 0 and data. Is full report submitted? Yes No If "no" explain: ,_
CL --E -a:; c c co 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 ~ecti2n of this Part of Report. . . -ff /he c h411ne / '<.J c// . .e_ Jt?/;°,e"p~. ~1 ~/roy.J-.../·1 :z_
anol re s~,,,<·~/ 0,'IJ.. cye.-1//~ !:.1~e -;;/"/~-a, ~r:
Will 100-year flow be contained with one foot of freeboard? V Yes --No If
not, identify location and explain:
Are ROW I easements sized to contain channel and required maintenance space?
--Yes __ No If not, identify location(s) and explain:
7h~r-<:. ( 5 I? 0 !?ow t> .-ec~.5<"~11 .,,, f
STORMWATER DESIGN GU IDELINES
Effective February 2007
Page 17 of26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
! .
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 4 -Drainage Concept and Design Parameters Continued (Page 4. 9)
0 z
I
C'-· -0 a.> Ul
0 a.
0 ._ a..
Ul ~
'(3 co LL..
c 0 ~ a.> Q)
0
For each dry-type facilitiy:
Acres served & design volum
100-yr volume: free flow & plu
Spillway crest at 100-yr WSE? no
For each faci.lity what is 25-yr design Q, and de~ign of outlet structure}. .
Facility 1: Bo. 7 5C"'-c co" 5fr(.;c-/,;;,1 j>lau> /,,,-,_ P~']'I
Facility 2:
Do outlets and spillways dis9Jarge into a public facility in easement or ROW?
Facility1 : __ Yes _V_NNoo Facility2: __ Yes __ No
If "no" explain: 5~e / n."V/Cr,':;. ./,;, C>.j:/'s-, Jc: c A,:;.,,,.,.!/ t/'1/l .. ,, • .,_,.. f s
& at sp illway?
-----& ____ _
No V Yes
w ,-/( 1~1 c_lvc../~ Ct
Describe type and
5/-, //, ',., b ": :;1 ~ J
~ < For each, is spillway surface treatment other than concrete? Yes or no, and describe:
Facility 1:
Facility 2:
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:
Facility 2:
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 18 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 4 -Drainage Conce~t and Design Parameters l Continued (Page 4.10)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (contin~d)
Do structures comply with B-CS Specifications? t:.:;j or no, and explain if "no":
Facility 1;
Ul Q) :+J =~ ~ Q) Facility 2: LL ::J c c~ 0 c :+J 0 cu Q) ~ a:; For additional facilities provide all same information on a separate sheet.
0
Are parking areas to be used for detention? ____iL" No --Yes What is
maximum depth due to required design storm?
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:
C'-· Ul Cl c '(ii
Ul Are culverts parallel to public roadway alignment? __ Yes No Explain: 0 --..... Ul u
Q) Q)
rn >-
> I ·;:::: Creeks at Private Drives: Do private driveways, drives, or streets cross drainage Cl.. rn ways that serve Above-Project areas or are in public easements/ ROW?
'O 0 No Yes If "yes" provide information below. Q) z ----~vf How many instances? Describe location and provide information below.
Q) Location 1: ..2!
::J u
Q) Location 2: ..... <(
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
Effective February 2007
Page 19 of26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ____ _
r
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 4-Drainage Conce~t and Design Parameters l Continued (Page 4.11)
· , $tC>fm~ater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Named Regulato~ 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 ..:::: en -- --
(!) location and provide the information below.
en (ti Instance 1: Q) .._
>-~ I~ Instance 2:
Instance 3: c 0 o~ z E
Yes or No for the 100-year design flow: 1 2 3
1~ Headwater WSE 1 foot below lowest curb top?
Spread of headwater within ROW or easement?
E C-· Cll Is velocity limited per conditions (Table C-11)? en en g> 1:l Explain any "no" answer(s): ·-c ~ Cll
0 c .._ 0
(.):;:::;
>-Cll Cll (.) s: ..Q
1:l (!) Cll .0 O .-.._ .._ Minor Collector or Local Streets: Will culverts serve these types of streets?
(.) (.) No Yes How many instances? for each identify the ·-en -Q) -- ---§ 1:l location and provide the information below:
CL Q)
.._. CL Instance 1: Cll~
1:l >-Instance 2: Q) c en Cll :J ..._ Instance 3: 2 0 .._ en
(!) Q) ~u For each instance enter value, or "yes" I "no" for: 1 2 3 :J c (.) Cll Design yr. headwater WSE 1 ft. below curb top? Q) t) .._ c <·-100-yr. max. depth at street crown 2 feet or less? Q) .._
0 Product of velocity (fps) & depth at crown (ft)= ? E .._ g Is velocity limited per conditions (Table C-11 )?
Limit of down stream analysis (feet)?
Explain any "no" answers:
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 20 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
r
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 4 -Drainage Concegt and Design Parameters I Continued (Page 4.12)
Storrnwater 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:
:a-Are flumes or conduit to discharge into or near surfaced approaches to culvert ends? Q) No Yes If "yes" identify location(s), describe outfall design treatment(s): :J c ----~
0 ~
(/) -.... Q) ~ :J Is scour/erosion protection provided to ensure long term stability of culvert structural u 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 8-CS Tech. Specifications?
--Yes --No If not, explain in Special Design Section of this Part.
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 21 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 4 -Drainage ConceQt and Design Parameters I Continued (Page 4.13)
. ' ',··. . .Stormv,vater 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?
(j)
(i)
OJ -0 'i::
a:i
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 ro Plan (SW3P) ::i a established for
'-project construction? Q) -~ --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?
STORMWATER DESIGN GUIDELI NES
Effective February 2007
Yes -- --
Page 22 of 26
No If "no" explain:
APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 4 -Drainage Conce~t and Design Parameters I Continued (Page 4.14)
: . . . . ' . . ...... Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Special Designs -Deviation From 8-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 .. ,.. '· "
1. ·.' .. . .. , .. -" ·' ,, .
Hydrology /
Is a map(s) showing all Design Drainage Areas provided? v Yes No ----
Briefly summarize the range of applications made of the Rational Formula:
(/).,,ne "•\ d el-r. Ii r,.,"'
/(t:tJ ... ,,,,, I 1--YrfYl)~ lva 5 U5f'.:>d -Cr +~ ,._ 411.<f I 7 >I$. .,L :s:.k ,,,.,
o/..,/·jll? ,;, le: Is ~ 1.-· lfe.--/!.?(<.) ~.
I I
What is the size and location of largest Design Drainage Area to which the Rational Formula
has been applied? J :> 2 3 acres Location (or identifier): {Jf-J ll/34 'f-/LjJ 8
;11 ~fo.-,vt Clio mv<?/
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 23 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 4 -Drainage Conce~t and Design Parameters I Continued (Page 4.15)
. . .
Design Parameters (continued)
Hydrology (continued) Usr.cl rn1:~ '~
In ~ing determinations for time of concentration, was segment analysis used? ()+ 10 j'>1 I .°'1 L
\. No Yes In approximately what percent of Design Drainage Areas? /0() %
As to intensity-duration-frequency and rain depth criteria for determining runoff flows, were any
criteria other than those provided in these Guidelines used? _·_No vYes If "yes"
identify type of data, source(s), and where applied: -/:~ _l_n,"f."ct/ q,, d cd?/t 51c ... + Lo-5$ /!Jc-/li o./ I h. i-1-E c -/-11"11 s
fr<---~"'"'"'I"/ t"h e •• -/ ru I'\ /) f'-1' r,.J·e . I I S' <?e (..";? /11/v -le / o;, I _s:·,.
~-Jkc/u••/ ;-c-(' ;,--/.
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 Io 10
Storm drain system for local streets ID 10
Open channels
Swale/buried conduit combination in lieu of channel
Swales
Roadside ditches and culverts serving them
Detention facilities: spillway crest and its outfall 2, /0, 2 S"" SO 10.:J /oo
Detention facilities: outlet and conveyance structure(s) I' I I
Detention facilities: volume when outlet plugged
Culverts serving private drives or streets
Culverts serving public roadways
Bridges: provide in bridge report.
Hydraulics
What is the range of design flow velocities as outlined below?
Design flow velocities; Gutters Conduit Culverts Swales Channels
Highest (feet per second) 7. 4'1
Lowest (feet per second) 2, 4 g
Streets and Storm Drain Systems Provide the summary information outlined below:
Roughness coefficients used :
For conduit type(s) .. o L3
STORMWATER DESIGN GUIDELINES
Effective February 2007
For street gutters:
Page 24 of 26
-o;L/
Coefficients:
APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 4 -Drainage Conce~t and Design Parameters I 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? .....t..:::::_No Yes Head and friction losses v No Yes ----Explain any "yes" answer:
In conduit is velocity generally increased in the downstream direction? Yes V-No --Are elevation drops provided at inlets, manholes, and junction boxes? L-Yes --No
Explain any "no" answers:
Are hydraulic grade lines calculated and shown for design storm? 0es __ No
For 100-year flow conditions? ~es __ No Explain any "no" answers:
What tailw~ter condition_s wer~ assumed at outfall point(s) 6 the stor,J drain system? Identify
each location and explain: S hal/oc.v -/a,/ . .:..11..ff',. 0.5 ft / · . Jo _
Th . . . h I A I . fh I C1 s . lit ·15 Q ~---"' J> r 5> Ci5.-,; ~'°'\ -j c> a:S~v /Y1/' ,~,,, . 4 .
t.ur-1/ he c~11 :;frvcf.-J tv1i-A A 2 o-1 f)e vlevel~A?<''it f
Open Channels If a HEC analysis is utilized, does it follow Sec Vl.F.5.a? __ Yes __ No
Outside of straight sections, is flow regime within limits of sub-critical flow? -$f!!€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
Effective February 2007
Page 25 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _
SECTION IX
APPENDIX D -TECHNICAL DESIGN SUMMARY
Part 4 -Drainage Concept and Design Parameters Continued (Page 4.17)
. Design Parameters (contfr1ued)
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
/-!Ee H/l? 5 v 3. I o
5~orrn C/-J{j V lf . /
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 Ill , 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
Desi n Summa Draina e Re ort b si nin and sealin below.
"This reporl (plan) for the drainage design of the development named in Patt B was prepared
by me (or under my supervision) in accordance with provisions of the Bryan/College Station
Unified Drainage Design Guidelines for the owners of the properly. All licenses and permits
required by any and all state and federal regulatory agencies for the pr drainage
ents have been issued or fall under applicable general permi
State of Texas PE No. 6S-9 2 3
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 26 of 26
(Affix Seal)
APPENDIX. D: TECH. DESIGN SUMMARY
As Revised ___ _