HomeMy WebLinkAboutDrainage ReportDRAINAGE REPORT
FOR
CARTER'S CROSSING
Phase 2
College Station, Texas
JULY9 2010
Io - /63
-7-aS-oD
MBESI# 1015-0005
McCLURE & BROWNE ENGINEERING/SURVEYING, INC.
LLLJJJn I I I��� IUUB Woodcrcck Urivc, Soitc 103 • Collcgc S ation,'i'cxas 77845
II I I (979) 693-3838 • Fax: (979) 693-2554
Carter's Crossing, Phase 2
Stormwater Management Technical Design Summary Report
MBE5I #1015-0005
PART 1— Executive Summary Report
Section 1— Contact Information:
Project Designer: McClure and Browne Engineering and Surveying, Inc.
1008 Woodcreek Drive, Suite 103
College Station, TX 77845
979-693-3838
Project Developer: Carter's Crossing Venture
311 Cecilia Loop
College Station, TX 77845
979-846-8788
Submittal Date: July 28, 2010
Section 2 — General Information:
Carter's Crossing, Phase 2 is the third of four phases of Carter's Crossing to be developed. Phase 1 and
Phase 3 have been completed. The subdivision is located in east College Station. This phase will extend
Forest Oaks Drive. 40 lots will be developed. The area of
Appomattox Drive, Raintree Drive and construct
proximately 12 acres. The plan is based on the Preliminary Plat submitted May 2007.
development of phase 2 is ap
Section 3 — Project Location:
Carter's Crossing is located in east College Station along Raintree Drive and Appomattox Drive. The
entire project site is located within the city limits of College Station. Phase 2 is located within the Carter's
Crossing subdivision boundaries. Phase 2 is bounded by Raintree Subdivision to the north. To the east is Carter's
Creek. To the south and west is the existing and future Carter's Crossing Subdivision.
The entire site is located within the Carter's Creek Drainage Basin. No portion of the site is shown to be
within the 100-year floodplain, so it is not currently regulated under the National Flood Insurance Program.
Based on Table B-1, Appendix B of the Unified Stormwater Design Guidelines, Carter's Creek from
Navasota River upstream needs evaluation for detention for flood control. Previous reports were submitted with the
construction of Phase 3 that show detention is not required.
Section 4 — Hydrologic Characteristics:
The project where lots are to be developed is mostly covered by trees
There are no existing drainage easements or ROW on the property. With this development drainage
easements and ROW will be provided.
Stormwater Management Technical Design Summary Report Page 1-of 2
Carter's Crossing, Phase 2
Section 5 — Stormwater Management:
As stated in Section 3, no detention is required and storm water will be discharged directly into the
tributary of Carter's Creek. Proper end treatments will be used to prevent erosion.
Section 6 — Coordination and Permitting:
No coordination or permitting is required for this development.
Section 7 — Reference:
Report
Technical Design Summary Report
Exhibit A
Fema Floodplain Map Excerpt
Exhibit B
Storm Drain Drainage Area Map
Exhibit C-1
Rational Formula Drainage Area Calculations
Exhibit C-2
Inlet Computations
Exhibit C-3
Pipe Size Calculations
Exhibit C-4
Hydraulic Grade Line — 10-Year Storm
Exhibit C-5
Hydraulic Grade Line — 100-Year Storm
Exhibit F
Hydraulic Grade Line Drawings
Stormwater Management Technical Design Summary Report Page 2 of 2
Carter's Crossing, Phase 2
APPENDIX D - TECHNICAL DESIGN SUM
The Cities of Bryan and College Station both require storm drainage design to follow these
Unified Stormwater Design Guidelines. Paragraph C2 of Section III (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 III 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.
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,
STORMWATER DESIGN GUIDELINES Page 1 of 26 APPENDIX. D: As TECH.
DESIGN UMruary ARY
Effective February 2007
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
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 ETJ 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 ! 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 -page drainage report dated , one set of
construction drawings (_sheets) dated and a
-page specifications .document dated comprise
the drainage report for this project."
STORMWATER DESIGN GUIDELINES Page 2 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
APPENDIX D - TECHNICAL
Part 2 — Project Administration
Start (Page 2.1)
Engineering and Desi n Professionals Information
Engineering Firm Name and Address:
Jurisdiction
City:
I x
Bryan
College Station
McClure and Browne Engineering/Surveying, Inc.
1008 Woodcreek Dr., Suite 103
College Station, TX 77845
LI
Date of Submittal:
LJune, 2010
Lead Engineer's Name and Contact Info. hone e-mail, fax):
Other:
Jeffery Robertson, PE, PH: 693-3838, FX: 693-2554, Jeffr@mcclurebroeme.com
Supporting Engineering /Consulting Firm(s):
Other contacts:
Developer / Owner / Applicant Information
Developer / Applicant Name and Address: _
Phone and e-mail:
979-846-8788
er's Cossing Venture
Loopege ation, TX 77845
[J1�1,Cc11S1t1'a
Property Owner(s) if not Developer / Applicant (& address):
Phone and e-mail:
Project Identification
Development Name:
Carter's Crossing, Phase 2
Is subject orooartv a site roject, a single-phase subdivision, or part of a multi -phase subdivision?
Multi -phase subdivision If multi -phase, subject property is phase of.
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 hases. For most recent earlier hase Include submittal a d revie da
Phase 1 and 3 have been completed. Phase 4 will be developed in the future.
General Location of Project Area, or subject property (phase):
Access to the Project Area will be from Raurtree Drive and Appomattox Drive.
In City Limits?
Bryan:
College Station: 12 acres.
Extraterritorial Jurisdiction (acreage):
Bryan: College Station:
Acreage Outside ETJ:
STORMWATER DESIGN GUIDELINES Page 3 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
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:
develo meats:
Raintree Drive
Appomattox Drive
Named Regulatory Watercourse(s) & Watershed(s): Tributa Basin s
Carter's Creek Carter's Creek
Plat Information For Project or Subject Property (or Phase)
Preliminary Plat File #:
Final Plat File #: Date:
I
Name:
Status and Vol/Pg:
If two plats, second name: File #:
Status: Date:
Zoning Information For Project or Subject Property (or Phase)
Zoning Type: R-1 Existing or Proposed? Case Code:
Case Date Status: Existing
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:
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
APPENDIX D - TECHNICAL DESIGN SUMMARY
_Part 2 — Project Administration
I 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
With Other
Departments of
Jurisdiction
City (Bryan or
College Station)
Coordination With
Summarize need(s) & actions taken (include contacts & dates):
Non -jurisdiction
City Needed?
Yes _ No
Coordination with
Summarize need(s) & actions taken (include contacts & dates):
Brazos County
Needed? R
Yes—No�
Summarize need(s) & actions taken (include contacts & dates):
Coordination with
TxDOT Needed
Yes _ No R
'contacts
Summarize need(s) & actions taken (include dates):
Coordination with
TAMUS Neede
Yes _ No R
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 ins aces below.
EntityPermitted
or
Status of Actions (include dates)
Approved ?
US Army Crops of
Engin rs
NoYes —
US Environmental
Protection Agency
No 1 "I Yes_
Texas Commission on
Env' entaI Quality
No 1=' I Yes _
Brazos River
Authorit
No X Yes _
STORMWATER DESIGN GUIDELINES Page 5 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
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?
Land is currently not developed. The area is wooded.
Redevelopment of one platted lot, or two or more adjoining platted lots.
Site
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
n 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.
Subdivisions: number of lots by general type of use, linear feet of streets and
Describe
drainage easements or ROW.
Nature and
Size of
40 Lots, Single Family Housing.
Proposed
2663 LF of Street Construction
Project
Is any work planned on land that is not platted
If yes, explain:
or on land for which platting is not pending?
MNo Yes
FEMA Ftoodptains
Is any part of subject property abutting a Named Regulatory Watercourse
No X Yes
(Section II, Paragraph B1) or a tributary thereof?
Is any part of subject property in floodplain
No
X
Yes Rate Map
��
area of a FEMA-regulated watercourse?
Encroachment(s)
Encroachment purpose(s): site(s) -E� Road crossing(s)
into Floodplain
areas planned?
_Building
�X Utility crossings) _ Other (explain):
No
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.
Hec-HMS and Hec-RAS studies have been completed to delineate the floodplain and for design
of the Appomattox Culvert.
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?
Reference the stud & date here and attach cony if not already in Qily fil
Yes
R
Drainage Report for Carter's Crossing Subdivision Phases 1 through 4, June 2007
Is the stormwater maraaaaetn ent plan for the property in substantial conformance with the
earlier study? Yes'1�� No If not, explain how it differs.
No
If subject property js not part of multi -phase project, describe stormwater management
plan for the property in Part 4.
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
therewith.
Do existing topographic features on subject property store or detain runoff? _ No Yes
Describe them (include approximate size, volume, outfall, model, etc).
Any known drainage or flooding problems in areas near subject property? X 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. 51 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 made?
Based on the 2007 study and an agreement with the downstream property owner stormwater is
able to reach Carter's Creek without adversely impacting this project or the downstream property.
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? X No _Yes If yes,
describesplits below. In Part 4 describe design concept for handling this.
Watershed or Basin
Larger acrea a
Lesser acreage
Above -Project Areas(Section II, Paragraph B3-a)
Does Project Area (project or phase) receive runoff from upland areas? _ No X 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);
There are four locations ofupland flow:
1. Gutter Flow from animate Drive
2, Storm Drain outfall from storm drain system at the end of Summer Drive.
3. Shallow concentrated flow that entms the property where Appomattox Drive will terminate at the Noreup-Gmarman property.
4. Smell creek that starts on the Noaluup-Grumman property and is the tributary that the Appomattox Drive culvert is designed to convey.
Flow determination: Outline hydrologic methods and assumptions:
Does storm r
No
drain from public easements or ROW onto or across subject property?
X Yes If yes, describe facilities in easement or ROW:
1. Gutter flow from Reintres Drive enters tiro property
_. Storm Drain outfall from storm drain system at the end of Summer Drive
Are changes in runoff characteristics subject to change in future? Explain
No
Conveyance Pathways (Section 11, Paragraph C2)
from study property drain across to
or tributary? No x
roperties before reaching a Regulatoryrse
Yes
FMustrunoffff
length and characteristics of each conveyance pathway(s). Include ownership ofes).onveyed
in a defined tributary approximately 2000 If to Carter's Creek. The tributary is on thef the Guseman Family Trust and the City of College Station Treatment plant. The tributary on theamily Trust is within the FEMA floodplain study for Carter's Creek.
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)?
No
Yes
Where runoff must cross lower properties, describe characteristics of abutting lower
property(ies). (Existing watercourses? Easement or Consent aquired?)
The Guseman Family Trust property is wooded and undeveloped. The existing tributary is on the south side
Pathway
of the property abutting the College Station Sewer Treatment Plant. A consent agreement with the
Areas
downstream property owners was acquired with the development of the earlier phases.
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? 0- No Yes If yes, explain:
STORMWATER DESIGN GUIDELINES Page 9 of 26 APPENDIX. D: TECH, DESIGN SUMMARY
Effective February 2007 As Revised FebruarV 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.
There are four locations cropland flow:
5. Gutter Flow from Reintree Drive— This flow is captured in the propsed Stmm Drain system
6. Storm Drain outfall son storm drain system at the end of Summer Drive— This storm drain system will be extended along
Appomattox Drive
9. Shallow concentrated flow that enters the property where Appomattox Drive will terminate at the Northrup-Gmmmanproperty.
This stonnwater will be captured in inlets on Appomattox Drive,
8. Small creek that starts ca the Nodhmp-Gmmman property and is the tributary that the Appomattox Drive culvert is designed to
convey — This storm water will be conveyed through the Appomattox Drive Culvert.
Discharge(s) To Lower Property(ies) (Section 11, 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
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 # )
As established in the Drainage Study submitted in 2007, the post development runoff is increased compared
to the pre development runoff. Per agreement with the downstream property owner this increase is
accepted and is conveyed to Carter's Creek without causing a negative impact to the downstream property.
Scenario 2: Provide general description of how release(s) will be managed to pre -development
conditions (detention, sheet flow, partially concentrated, etc.). (Attached Exhibit #_--)
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 _ 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 Project 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?
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 # )
3. B phase for 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
_ Yes Summarize type of BMP and extent of use:
c
rn I
_No
N
o
O z
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.
elements Conduit elements _ Channel features
(DDetention
<
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
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters Continued (Page 4.3)
Stormwater Management Concept (continued)
Within Proiect Area Of Multi -Phase Project (continued)
a include bridge(s) or culvert(s)? —No x Yes Identify type and
d In which phase(s).
pomattox Drive
=detention/retenfion
ntion serves (will serve) overall Project Area, describe how it relates to subject
phase or site project (physical location, conveyance pathway(s), construction sequence):
Within Or Serving Subject Property (Phase, or Site)
If property part of larger ProjPLQrea, is design in substantial conformance with earlier analysis
and report for larger area? x 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?
Surfaces?
r
°� u
Steepest side slopes:
Usual front slopes:
Usual back slopes:
N r
Y I
Flow line slopes: least
Typical distance from travelway:
a
a
typical greatest
(Attached Exhibit# )
o
N Z
a
m
° x
Are longitudinal culvert ends incompliance with l3-CS Standard Specifications?
m
Yes No, then explain:
At intersections or otherwise, do valley gutters cross arterial or collector streets?
}
No _Yes If yes explain:
D
X
�
Are valley gutters proposed to cross any street away from an intersection?
o
No Yes Explain: (number of locations?)
mz
STORMWATER DESIGN GUIDELINES Page 12 of 26 APPENDIX. D: TECH, DESIGN SUMMARY
Effective February 2007 As Revised February 2009
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 o.6°° Usual 0.6% Greatest 324%
Are inlets recessed on arterial and collector streets? x Yes ^ No If "no',
identify where and why.
3 �
U
L V
3
N
(D
N
Will inlets capture 10-year des-�i n stormflow to prevent flooding of intersections (anerl
J with arterial or collector)? X L Yes _ No If no, explain where and why not.
Will inlet size and placement prevent exceed��n�❑�allowable water spread for 10-year
design storm throughout site (or phase)? --L-t Yes _ No If no, explain.
Sag 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?
-i A - Yes _ No Explain "no" answers.
Will 100-yr stormflow be contained in combination of ROW and buried conduit on
whole length of all streets? _F—xl_ Yes _ No If no, describe where and why.
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? x No _Yes Identify length(s) and where
used.
r
Pipe runs between system Typical SO if Longest 414 tf
0 access points (feet):
aa) Are junction boxes used at each bend? -LXI- Yes _ No If not, explain where
'P.11XIand why.
c O
.@ z
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 of26 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).
1) Watercourse (or system), velocity, and angle?
s?
Storm Drain SD-1 discharges into the 8'x5' Box Culvert at a 90 degree angle with a velocity of 3.2
m
fps
O
E
2} Watercourse (or system), velocity, and angle?
""a
Storm Drain SD-4 discharges into the existing tributary at a 90 degree angle with a velocity of 5.8
o
fps
@
m
3} Watercourse (or system), velocity, and angle?
O
Storm Drain SD-5 discharges into the existing tributary at a 90 degree angle with a velocity of 5.8
�N
m .o
fps
Zf
E
For each outfall above, what measures are taken to prevent erosion or scour of
o
receiving and all facilities at juncture?
1)
All entrails will use Rock Rip Rap to dissipate energy and prevent erosion.
to
N
i9
Q.
2)
w
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):
r•
m
Flow line slopes (minimum and maximum):
m
0
Z
Outfall characteristics for each (velocity, convergent angle, &end treatment).
� x
3
N
q
Will 100-year design storm runoff be contained within easements) or platted ralnage
ROW in all instances? _Yes _No If "no" explain:
STORMWATER DESIGN GUIDELINES Page 14 of 26 APPENDIX. D: As Revised UM ARY
Effective February 2007
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 Drainage Concept and Design Parameters I Continued (Page 4.6)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase or Site) (continued)
Are roadside ditches used? X No _Yes If so, provide the following:
Is 25-year flow contained with 6 inches of freeboard throughout ? _ Yes _ No
_ Are top of banks separated from road shoulders 2 feet or more? _Yes ! No
d Are all ditch sections trapezoidal and at least 1.5 feet deep? Yes No
v
N For any "no" answers provide location(s) and explain:
0
P
CX
If conduit is beneath a Swale, provide the following information (each instance).
N
design flow contained in conduit/swale combination? _. Ye:
lain:
U13
0 m
Fpar
100-year storm flow? ROWEasement Widthz
cSurface
type, minimum
Conduit Type and size, minimum and mxcomum
slopes:
slopes, design storm:
0
w a
m
Inlets Describe how conduit is loaded (from streets/storm drains, inlets by
�
c �
m m
s
U
O
G
o
Access Describe how maintenance access is provided (to Swale, into con
0
0 E
� o
_o
v
Instance 2 Describe general location, approximate length:
m @
N N
� -('P_
Is 100-year design flow contained in conduit/swale combination? ,_ Ye
° o
If "no" explain:
m `o_
c
—
E 4)
Space for 100-year storm flow? ROW , Easement. Width _
oo
Swale Surface type, minimum
Conduit Type and size, minimum and
'm
and maximum slopes:
slopes, design storm:
IIIIIIIII�
a
° 0) Inlets Describe how conduit is loaded (from streets/storm drains, inlets by type;
3 0
m
Access Describe how maintenance access is provided (to Swale, into conau¢)
STORMWATER DESIGN GUIDELINES Page 15 of 26 APPENDIX. D: TECH.
Revised February SUMMARY
Effective February 2007 As
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:
G
d
o W
oIs
100-year design flow contained in swale? _Yes _ _ No Is swale wholly
}
within drainage ROW? _yes � No Explain "no" answers:
I
c"'i
Access Describe how maintenance access is provide:
m
' o
•3 Z
'6
O X
—
Instance 2 Describe general location, approximate length, surfacing:
a
m
r
c
ar
yeaign (flow containedNo Swale wholly
in Swale?No
is 100hin
drainage Explain "no" answers
`o
m
m O
W
Access Describe how maintenance access is provided:
U
O.
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 n
describe section shape & area, flow line slope (min. & max.), surfaces, and 100-year
0 w
design flow, and amount of freeboard:
m
Instance 1:
u,
c �
m �
E
a
Instance 2:
a
E o
z
Instance 3:
0
U
STORMWATER DESIGN GUIDELINES Page 16 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
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 x Yes
If" es" provide the information below.
Will small creeks and their floodplains remain undisturbed? Lx. 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.
-o
m
Watercourses (and tributaries): Aside from fringe changes, are Regulatory
Watercourses proposed to be altered? No Yes Explain below.
Submit full report describing proposed changes to Regulatory Watercourses. Address
E
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:
n
E
m
c
s
All Proposed Channel Work: For all proposed channel work, provide information
v
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
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? For each provide info. below.
For each dry -type facilitiy:
Facility 1
Facility 2
Acres served & design volume + 10%
100-yr volume: free flow & plugged
Design discharge (10 yr & 25 yr)
Spillway crest at 100-yr WSE?
—yes no
_yes —no
Berms 6 inches above plugged WSE?
—yes no
_Yes no
Explain any "no" answers:
(r
r
For each facility what is 25-yr design O, and design of outlet structure?
Facility 1:
0
Facility 2:
�z
I X I
Do outlets and spillways discharge into a public facility in easement or ROW?
T
Facility 1: —Yes —No Facility 2: Yes No
v
If "no" explain:
0
0
a
0
a
For each, what is velocity of 25-yr design discharge at outlet? & at s illwa ?
w
Facility 1: & Facility 2: &
.3
Are energy dissipation measures used? —No —Yes Describe type and
cu
u-
location:
c
0
c
0
d
0)
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 Page 18 of 26 APPENDIX, D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
ENDIX D - TECHNICAL DESIGN SUMMAMY
Continued (Page 4.10)
-
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
E=ate
ly with B-CS Specifications? Yes or no, and explain ifi"noevC w.O COWies provide all same information on a separate sheet.
0
Are parking areas to be used for detention? _ 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:
r•
N
D1
C
oAre culverts parallel to public roadway alignment? _ Yes _ No Explau
U N
4% }
d
Q Creeks at Private Drives: Do private driveways, drives, or streets cross drainage
m ways that serve Above -Project areas or are in public easements/ ROW?
° No Yes If "yes" prov
ide information below. .w �2 .----- ,:� --i How many instances? Describe location and provide information below.
0 Location 1:
3
U
m I 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 Page 19 of 26 APPENDIX. D: As TECH.
DESIGNised UM ARY
Effective February 2007
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 Regulator Watercourses & Tributaries): Are culverts proposed on these
facilities? No x Yes, then provide full report documenting assumptions,
_
criteria, analysis, compu e programs, and study findings that support proposed
design(s). Is report provided? x Yes —No If "no", explain:
Arterial or Maier Collector Streets: Will culverts serve these types of roadways?
Nx
No How many instances? For each identify the
m
—Yes
location and provide the information below.
} a
instance 1:
Instance 2:
x o
Instance 3:
c
0
Yes or No for the 100-year design flow:
1
2
3
z E
o
Headwater WSE 1 foot below lowest curb top?
c
@
Spread of headwater within ROW or easement?
E
Is velocity limited per conditions (Table C-11)?
"no"
N c
Explain any answer(s):
N @
O C
U
T @
@ U
?y �
a
@
o �
Minor Collector or Local Streets: WiII culverts ser ese types of streets?
0 w
No x Yes How many instances? for each identify the
mo
_
location and provide the information below:
Instance 1:
Q Appomattox Drive
fl. m
y
Instance 2:
yc
@
0 o
Instance 3:
tf
N
0
For each instance enter value, or "yes" / "no" for:
1
2
3
Design yr. headwater WSE 1 ft. below curb top?
Yes
¢
100-yr. max. depth at street crown 2 feet or less?
L00' Depth 0.64' below top of curb
E
Product of velocity (fps) & depth at crown (ft) = ?
Is velocity limited per conditions (Table C-11)?
Limit of down stream analysis (feet)?
800 If
Explain any "no" answers:
STORMWATER DESIGN GUIDELINES Page 20 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 4.12)
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 x No If not,
identify locations and intersect an le(s), and justifythe—n s
Culvert intersects at a 60 degree angle to match existing tributary alignment.
Does drainage way ali� ent change within or near limits of culvert and surfaced
approaches thereto? �J No _Yes If "yes" identify location(s), describe
change(s), and justification:
Are flumes or conduit to discharge into culvert barrel(s)? ^ No x Yes If yes,
identifv locations and providejustification:
The storm drain system for Appomattox Drive discharges into the culvert barrels. HGL design shows that
the drainage system is adequate.
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
0
U
N
1'
Is scour/erosion protection provided to ensure ymg term stability of culvert structural
components, and surfacing at culvert ends? Yes _ No If "no" Identify
locations and provide justification(s):
Will 100-yr flow and spread of water be fully contained in street ROW, and/or
J Yes _ No if not, why not?
drainage easements/ ROW? x
Do appreciable hydraulic effects of any culvert extend downs or upstream to
neighboring land(s) not encompassed in subject property? No Yes If
"yes" describe location(s) and mitigation measures:
II 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
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? J
XL
No
If "yes" provide the following information. �
—Yes
Name(s) and functional classification of the roadway(s)?
What drainage ways) is to be crossed?
rn
v
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:
r
Pollution Prevention
Plan (SW3P)
Construction Entrance, Silt Fence, Inlet Protection
0
established for
`m
project construction?
io
—No M 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
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 TOuffalls
_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? x Yes No
Biiefly summarize the range of applications made of the Rational Formula:
The Rational Formula was used for the storm drain inlet and pipe sizing
design.
What is the size and location of largest Design Drainage Area to which the Rational Formula
has been applied? 5.59 acres Location (or identifier): DranageAreaforinteul
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 dyieqinations
No
for time of concentration, was segment analysis used?
x Yes In approximately what percent of Design Drainage Areas?
too
%
_
As to intensity -duration -frequency and rain depth criteria for determining runoff flows, were any
criteria other than those provided in these Guidelines used? -- I 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
Storm drain system for local streets
to
to
Open channels
Swale/buried conduit combination in lieu of channel
Swales
Roadside ditches and culverts serving them
Detention facilities: spillway crest and its outfall
Detention facilities: outlet and conveyance structure(s)
Detention facilities: volume when outlet plugged
Culverts serving private drives or streets
Culverts serving public roadways
too
zs
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)
.
5.8ps
3.2fps (I OYr)
(feet per second)
z fp
o.7fpsLowest
zsfps (tooYr)
Streets and Storm Drain Systems Provide the summary information outlined below:
Roughness coefficients used: For street uters: 0.018
For conduit type(s) RCP rIDPa Coefficients: o ots o.ots
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, ar��a�"L s,�sumptions other than allowable per Guideline 2
No Yes
Inlet coefficients? No _Yes Head and friction losses - _
J
Explain any "yes" answer:
In conduit is velocity generally increased in the downstream direction? X Yes No
Are elevation drops provided at inlets, manholes, and junction boxes? X Yes _ No
Explain any "no" answers:
Are hydraulic grade lines calculand shown for design storm? X Yes _ No
For 100-year flow conditions? LxYes _No Explain any "no" answers:
What tailwater conditions were assumed at outfali point(s) of the storm drain system? Identify
each location and explain:
The tailwater conditions are based on water surface elevations determined with the Hec-PAS study.
Open Channels If a HEC analysis is utilized, does it follow Sec VI.F.5.0 —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?
Inlet Control
Entrance, friction and exit losses:
Entrance Loss = 0.15
Friction = 0.012
Exit Loss = I
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
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
Microsoft Excel: For Rational Formula storm inlet and pipe sizing and HGL calculations
HEC-RAS 4.1.0 Jan 2010: Flood Plain Analysis and Culvert Sizing
HEC-HMS 3.4: Runoff Calculations for HEC-RAS study
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 8 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 property. All licenses and permits
required by any and all state and federal regulatory agencies for the proposed drainage
impro ements issued or fall under applicable general permits:"
Xeeen
Yo�a.�o��x�
L. (Affix Seal) ZE OF TF.yyl
..............A ..*.
Lic e rofes tonal Engineer.................................:•
X JEFFERY L. ROBERTSON
9 7�f5 ,:....:..........
State Texas PE No. �� 9: 94745
of
.Nx�tS/ONA\—
STORMWATER DESIGN GUIDELINES Page 26 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
/
\\
PROJECr
NTS
EXHIBIT
Flood Insurance Rate Map Excerpt
Brazos County, Texas
(Ind Incorporated Areas
��
Map Numbers: 48041C0163C
Effective Date: July 2'1992
//4 l �^
I.t
_.. \ j!
\;
J-/�
5B // A 0.5 AC 1
J -
�1} fiI 1
2 t Zoe 1 1
0.0 c 0-AG .89
1.61
16A 1
9.05 C o.4 AC i
16 0 —
A=
J
2.86AC
{ E—
��� J7—= -
4.2 AC
J
5.59 AC
n
AC�
EXHIBIT "B"
DRAINAGE AREA MAP
® COLLEGE STATION, BRAZOS COUNTY, TEXAS
SCALE: 1 = 100'Jr40t
McCCURE & BROWNE ENG/NEER/NG/SURYEY/NG /NC.
D 5U' 100' • 1996 W000creek OnYe, SLite 163, cave SYatioa 1 778A
M (979) 693-3636 Fox: (979J 693-25
FFI
EXHIBIT C-1
Rational Formula Drainage Area Calculations
Carter's Creek Phase 2
U'
Z
K
❑
Q W
J W Q
❑ W
O Z a:W
h ❑ Q
Q
Z
M
R'
Z
W
i
Q
n-
Q
Q
1-
Q
F
O
Z
a(7
W "z
i W
O J
O
Z
K Ji
W J
> Q
O LL
O
LL
F(7
�' Z
W
0 J
30
�-
FJ
F J
7 Q
a LL
O
J
W
>
~
N
U I
W
N
7
v
N
Q
!2
N
OFCf
O
b
�
N
Q
O
T
N
Q
O_
o
Q
M
AC. 1 0.4
0.55
0.9
ft
ft
ft.
ft.
ftls
min
min
InIHr
cfs
In/Hr
cfs
In/Hr
cfs
WNHr
cfs
In/Hr
cfs
IIn/Hr
cfs
1
0231 0.00
0.23
0.00
0.13
100.0
1.0
1.0
1.0
0.1
19.1
19.1
4.55
0.6
5.6
0.7'
6.4
0.8
7.3
0.9
8.3
1.0,
9.3
1.2
2
1.76, 0.00
1.76
0.00
0.97
191.0
2.0
217.0
2.1
0.2
32.9
32.9
3.27
3.2
4.1
4.0
4.7
4.5
5.4
5.2
6.1
5.9
6.9
6.7
3
2.861 0.00
2.86
0.00
1.57
120.0
1.0
980.0
6.6
0.7
24.9
24.9
3.90
6.1
4.8
7.6
5.5
8.7
6.3
9.9
7.2
11.3
8.1'
12.8
4
4.25'' 0.00
4.25
0.00
2.34
290.0
12
980.0
6.6
0.3
66.3
66.3
2.02
4.7
2.6
6.0
3.0
7.0
3.4
8.0
3.9
9.2
4.5
10.5
5A
0.56 0.00
0.56
0.00
0.31
52.0
0.5
354.0
2.8
0.6
11.7
11.7
5.87
1.8
7.2
2.2
8.1
2.5
9.2
2.8
10.4
3.2
11.7
3.6
5B
0.11 0.00
0.11
0.00
0.06
10.0
0.1
165.0
1.0
0.9
3.1
10.0
6.33
0.4
7.7
0.5
8.6
0.5
9.9
0.6
11.1
0.7
12.5
0.8
6A
0.55''. 0.00
0.55
0.00
0.30
92.0
0.9
354.0
2.8
0.4
18.6
18.6
4.61
1.4
5.7
1.7
6.4
2.0
7.4
2.2
8.4
2.5
9.5
2.9
6B
0.11 0.00
0.11
0.00
0.06
10.0
0.1
165.0
1.0
0.9
3.1
10.0
6.33
0.4
7.7
0.5
8.6
0.5
9.9
0.6
11.1
0.7
12.5
0.8
10
1.08 0.00
1.08
0.00
0.59
216.0
3.0
154.0
0.9
0.2
33.1
33.1
3.25
1.9
4.1
2.4
4.6
2.8
5.3
3.2
6.1
3.6
6.9
4.1
11A
1.68 000
1.68
0.00
0.92
215.0
3.0
276.0
1.7
0.2
33.0
33.0
326
3.0
4.1
3.8
4.7
4.3
5.4
6.0
6.1
5.6
6.9
6.4
11 B
5.59 0.00
5.59
0.00
3.07
115.0
12
954.0
8.0
0.8
22.3
22.3
4.16
12.8
5.2
15.9
5.9
18.0
6.7
20.7
7.6
23.5
8.6
26.5
12
0.89 0.00
0.891
0.00
0.49
73.0
0.7
373.0
3.0
0.5
15.4
15.4
5.111
2.5
6.3
3.1
7.1
3.5
8.1
4.0
9.2
4.5
10.4
5.1
13
! 1.13 0.00
1.13'
0.00
0.62
60.0
0.6
482.0
4.8
0.7
13.1,
13.1
5.56
3.5
6.8
4.2
7.7
4.8
8.8
5.4
9.9
6.2
11.2
6.9
14
0.00 0.00
0.00
0.00
0.00
1.0
1.0
1.0
1.0
0.4
0.1
10.0
6.33�
0.0
7.7
O.Oi
8.6
0.0
9.9
0.0
11.1
0.0
12.5
0.0
15A
0.46 0.00
0.46
0.00
0.25
192.0
1.9
81.0
1.0
0.1
33.4
33.4
3.23
0.8
4.0
1.0'
4.6
1.2
5.3
1.3
6.1
1.5
6.9
1.7
15B
0.34 0.00
0.34
0.00
0.19
69.0
0.7
155.0
0.9
0.3
14.9
14.9
5.22
1.0
6.4
1.2
7.2
1.4
8.3
1.5
9.4
1.8!
10.6
2.0
16A
0.05 0.00
0.05
0.00
0.03
10.0
0.1
95.0
1.2
0.6
3.1
10.0
6.33
02
7.7
0.2
8.6
0.2
9.9
0.3
11.1
0.31
12.5
0.3
16B
0.50 0.00
0.50
0.00
0.28
71.0
0.7
289.0
1.7
0.4
15.2
15.2i
5.16
1.4
6.3
1.7
7.1
2.0
8.2
2.2
9.3
2.5
10.4
2.9
20A
1.13 0.00
1.13
0.00
0.62
188.0
1.9
164.0
1.0
0.2
33.5
33.5
3.23
2.0�
4.0
2.5
4.6
2.9
5.3
3.3
6.1
3.8
6.9
4.3
20B
0.40 0.00
0.40
0.00
0.22
188.01
1.9
72.0
0.6
0.1
33.0
33.0
3.26
0.7
4.1
0.9
4.7
1.0
5.4
1.2
6.1
1.3
21A
0.64 0.00
0.64
0.00
0.35
80.01
0.8
473.0
3.5
0.6�
16.7
16.7
4.91
1.7
6.0
2A
6.8
2.4
7.8
2.8
8.9
'
10.0
3.5
21B
0.04 0.00004
0.00
0.021
10.0
0.1
70.0
0.6
0.4
3.1
10.0
6.33
0.1
7.7
0.2
8.6
0.2
9.9
0.2
11.1
0.2
12.5
0.3
'
I
I
7/27/2010
10150005-DR4-BCS.xis
Exhibit C-1
O
>
>1
d
d
v
i
Q
M
zDESCITION
L!14
Curb
Inlet
efs
cis
ft
ft
1
na
0.8
0.0
0.8
27
0.78%
0.17
0.38
1.7
1
0.8
Recessed Low Point Inlet
2.27
0.35
5
0
2
3.0
4.5
0.0
4.5
27
0.78%
0.32
0.38
2.6
2
4.5
Junction Box
0
3
6.0
8.7
0.0
8.7
27
0.78%
0.41
0.46
3.0
3
8.7
Recessed Low Point Inlet
2.27
3.82
5
0
4
SA
7.0
0.0
7.0
38
0.78%
0.38
0.46
2.9
4
7.0
Recessed Low Point Inlet
2.27
3.06
5
0
5A
na
2.5
0.0
2.5
38
0.78%
0.26
0.46
2.2
N/A
0
56
na
0.5
0.0
0.5
38
0.60%
0.15
0.46
1.4
5
3.0
Recessed Low Point Inlet
2.27
1.32
5
0
6A
na
2.0
0.0
2.0
38
0.78%
0.24
0.46
2.1
N/A
0
66
na
0.5
0.0
0.5
38
0.60%
0.15
0.46
1.4
6
2.5
Recessed Low Point Inlet
5
0
10
11A
2.8
0.0
2.8
38
0.60%
0.28
0.38
2.1
10
2.8
Recessed Low Point Inlet
5
0
11A
na
4.3
0.0
4.3
38
0.60%
0.33
0.38
2.3
N/A
0
11 B
na
18.0
0.0
18.0
38
3.24%
0.42
0.38
6.2
11
22.3
Recessed Low Point Inlet
10
0
12
na
3.5
0.0
3.5
38
1.71%
0.25
0.38
3.2
12
3.5
Recessed Low Point Inlet
K273
5
0
13
16B
4.8
0.0
4.8
27
3.24%
0.25
0.38
4.5
13
4.8
Recessed Inlet on Grade
10
0
14
na
0.0
0.0
0.0
27
0.60%
0.00
0.38
14
0.0
Junction Box
0
15A
na
1.2
0.0
1.2
27
1.24%
0.18
0.38
2.2
N/A
0
15B
na
1.4
0.0
1.4
27
0.60%
0.22
0.38
1.7
15
2.5
Recessed Low Point Inlet
5
0
16A
na
0.2
0.0
0.2
27
1.24%
0.10
0.38
1.5
N/A
0
16B
na
2.0
0.0
2.0
27
0.60%
0.25
0.38
1.9
16
2.2
Recessed Low Point Inlet
2.27
0.97
5
0
20A
na
2.9
0.0
2.9
27
0.60%
0.29
0.38
2.1
N/A
0
20B
na
1.0
0.0
1.0
27
0.85%
0.18
0.38
1.8
20
3.9
Recessed Low Point Inlet
2.27
1.72
5
0
21A
na
2.4
0.0
2.4
27
0.60%
0.27
0.38
2.0
N/A
0
21 B
na
0.2
0.0
0.2
27
0.10
0.38
1.2
21
2.6
Recessed Low Point Inlet
2.27
1.14
5
0
7/27/2010
10150005-DRA-BCS.xi s
Exhibit C-2
EXHIBIT C-3
PIPE SIZE CALCULATIONS
Carter's Creek Phase 2
W
L�
i„ r
rn
.y
W
•�°
w
v en
a
� c
py
w
°
v
Pr
c
W
*
on
C
°
W
py
F
rW.7
B
F"
y
F
zs
r~
W
F
F
F
Irl
pl
#
#
lAc.
Imin
yr
cfs
I cfs
#
cfs
%
fps
min
min
1
2
0.1
19.1
10
0.8rNo
1
0.8
0.02
18
0.7
24
0.54
19.63
2
4
1.1
32.9
10
5.11
5.1
0.13
24
2.6
51
0.32
33.22
3
4
1.6
24.9
10
8.71
8.7
0.38
24
4.5
41
0.15
25. 00
4
5B
5.0
66.3
10
14.91
14.9
0.13
30
3.0
414
2.28
68.57
5B
Cull
5.4
68.6
10
15.61
15.6
0.14
30
3.2
20
0.10
68.68
6B
CUI2
0.4
18.7
10
2.31
2.3
013
18
21
1
001
1870
10
11B
0.6
33.1
10
2.81
2.8
0.18
18
2.5
278
1.84
34.98
116
12
4.6
35,0
10
20.71
20.7
0.25
30
4.2
41
0.16
35,1512
13
5.1
35.1
10
22.81
22.81
0.31
30
4.6
60
0.22
35.36
13
14
5.7
35.4
10
25.51
No
1
25.5
0.38
30
5.2
232
0.75
36.11
14
15B
5.71
36.1
10
25.2
No
1
25.2
0.37
30
5.1
54
0.18
36.28
16B
16B
6.1
36.3
10
27.0
No
1
27.0
0.43
30
5.5
30
0.09
36.37
16B
HW1
6.4
36.4
10
28.3
No
1
28.3
0.47
30
5.8
40
0.12
36.49
20B
21 B
0.8
33.5
10
3.9
Yes
1
3.9
0.36
18
3.6
301
0.14
33.67
21B
HW2
1.2
33.7
10
5.6
Yes
1
5.6
0.74
18
5.1
20
0.07
33.73
"See Plan & Profile for pipe slope used (Pipe slope >or= Friction slope)
7/27/2010
10150005-D RA-BCS.Xls
Exhibit C-3
EXHIBIT C-4
HYDRAULIC GRADE LINE -10Yr. Storm
Carter's Creek Phase 2
Inlets
FL
FL
B inAl
e
Normal
De fh
SSEl
Normal
De 8r
Veloci
Velo
Endn
To
Della
O
Main
From
To
Upper
lower
WS EIeva
Leng81
Sf
PipeS
Lower
WS EIev
Upper
Hf
In
Out
HI
WS EIev
Inlet
Cherk I
Delta
i FUII
j Inletln
SB
Cull
249.12
249.03
254.18
20
0.168%
0.450%
250.41
254.18
250.50
0.03
4.28
5.44
0.09
254.30
256.23
OK
t.9288
25.6
4
4
5B
250.25
249.22
254.30
414
0.153%
0.249%
250.85
254.30
25t.88
0.63
4.85
4.28
0.02
254.95
259.4
OK
4.4474
19.0
3
3
4
255.4
255.2
254.95
41
a288%
0.488%
256.30
256.30
256.50
O.t2
0.00
4.85
OA6
256.96
259.4
OK
2.4443
14.7
0
2
4
251
250.75
254.954
51
OA00%
0.490%
251.55
254.95
251.80
0.05
2.57
4.24
0.04
255.05
259.01
OK
3.9622
14.7
1
1
2
255.96
255.84
255.058
24
0.012%
0.500%
256.18
256AS
256.30
0.00
0.00
257
0.13
256.43
257.46
OK
1.0343
6.9
0
16B
HW1
248.31
248.11
250.120
40
0.552%
0.500%
250.17
250.17
250.37
0.22
1 6.26
6.26
0.00
250.39
253.9
OK
3.5068
27.0
156
15B
76B
248.56
248.41
250.39
.0
30
0.503%
0.500°/a
250.4t
250.41
250.56
0.15
6.23
6.26
0.00
250.56
253.9
OK
3.3370
2].0
16
14
158
248.93
248.66
250.56
25.16
30
54
0.436%
0.500%
250.47
260.56
250.74
0.24
6.01
6.23
0.02
250.82
254.12
OK
3.3002
27.0
13
13
14
250.1
249.03
250.82
25.49
30
232
0.447%
0.461%
251.03
251.03
252.10
1.04
6.15
6.01
0.01
1 252.11
255.59
OK
3.4767
25.9
12
12
13
250.5
250.2
25211
2280
30
60
0.358%
0.500%
251.89
252.11
252.19
0.21
6d0
6.15
0.00
252.33
2557
OK
3.36]4
27.0
7t6
11B
72
250.81
250.6
252.33
20.66
30
41
0.294%
0.512%
252.16
252.33
252.37
0.12
3.66
6.10
0.18
252.64
25579
OK
3.t 522
27.3
10
10
11B
254
252.61
252.64
2.76
18
278
OA36%
0,500%
253.25
253.25
0.38
0.00
3.65
0.26
254.90
257.5
OK
2.5018
6.9
0
21B
HW2
250.12
249.98
251.14
5.60
18
20
0.558%
0.700%
250.88
251.14
1D2
0.11
4.02
4.97
0.07
251.32
254.33
OK
3.0119
8.2
208
20B
218
250.83
250.W
251.32
3.88
18
30
0,2 99%
0.500%
251.51
251.51
il4.64
.66
0.08
0.00
4.02
0.31
251.97
254.33
OK
2.3618
6.9
0
I
7/272010
10150005-DRA-BCSAJJ
Exhibit C-4
EXHIBIT C-5
HYDRAULIC GRADE LINE-100Yr. Storm
Carter's Creek Phase 2
[in
FL
FL
8 In
P. I
Normal
epth
Starfina
N..l
Depan
Velout
VelOtit
Buding
To
Endin
Della
O
Shl
Street
1 ROW
Flow
Contained
Main
Fmm
To
Upper
Lower
WS Bev
0100
Dia Length
St
Pipe
Loer
WS EIev
Upper
HI
In
Old
H'
WS Head
Inlet
I WS EIev
Check
Della
Sudaae
WidO
Slape
I Capeerty
in ROW
I Inlelln
58
Cult
249.12
249.03
255.54
23.65
Jp 20
0.39%
0.45%
250.54
255.54
250.93
0.05
4.41
5.91
0.12
255.74
25623
255.74
OK
0.49
0.00
35
0.60%
1 60.0]
Yee
4
4
se
26025
24922
255.74
Y52
30 414
0.35%
025%
261.1T
255.74
25275
1.45
525
6.61
0].06
vff.24
259.4
25/.24
OK
2.16
0.00
30
0.18%
1 65.49
Yes
3
3
4
255.4
255.2
257.24
1279
24 dt
0.63%
0.49%
256.60
2 .24
256.80
0.26
0.00
515
0.54
258.04
259.E
258.04
OK
1.36
0.00
2]
0.]6%
66.J2
Yea
0
2
4
251
250.75
251'.24
7.60
26 1 51
012%
0.49%
251.75
257.24
252.00
0.11
2.91
4.71
0.11
2SIA8
259.01
2 .46
OK
1.65
0.00
ZI
0.78%
66.32
Yes
1
1
2
255.96
255.36
257A6
1.18
10 24
0.02%
0.50%
256.25
29].46
256.37
0.01
9.00
2.91
0.16
25].W
257.46
257.46
Sureha a
=OA7
0.00
2]
0]0%
66.32
Yes
0
--im
-:mwsi
HW1
248.11
250.58
42.17
30 - 40
122%
0.50%
250.61
250.61
250.81
OAS
626
626
0.00
251.10
253.9
251.10
OK
2.80
0.00
n
0.60%
58.16
Yea
158
15B
16B
240.56
248AI
251.tp
d0.25
30 30
1.12%
0.50%
250.91
251d0
251.06
0.33
626
626
0.00
251.43
253.9
251.43
OK
2.47
0.00
00.60%
SI
Yes
14
14
156
248.93
248.88
251A3
37.48
30 54
0.97%
0.50%
251.16
251.43
251.43
0.52
6.01
626
0.02
251.98
254.12
251.98
OK
2.14
SAO
v
0.60%
58.15
Yu
13
13
14
250A
249.03
251.96
3].94
30 232
0.99%
0.46%
251.53
251.98
25Z60
2.30
626
6.01
0.02
254.30
255.59
254.30
OK
129
0.00
27
124%
135.16
Yes
12
12
13
250.5
250.2
254.30
1 M93
30 60
0]9%
0.50%
252.]0
25{.30
25&00
0.48
6.33
626
0.01
254F9
255.]
254]9
OK
0.91
0.00
J8
1.]t%
1p1A1
Y.
it8
11B
12
250.81
250.6
251]e
30.75
30!R251.69
253.10
254.]9
253.31
OS!
4.07
6.33
0.IS
25514
255]e
255.24
OK
0.55
0.00
30
3.24%
139.59
Yes
10
254
25261
25514
4.ID
10253.44
25514
254.63
0.83
0.00
4.W
0.32
256.39
257.5
255.39
OK
lmll
0.00
38
OZ0%
50.0]
Yes
a
250d2
249.98
25f.5]
8.32
1025t22
25L5]
25136
025
4.37
51]
0.07
25L85
354.33
25i08
OK
2.65
0.00
2]
0.85%
6913
Yes
208
250.83
250.60
25tee
SFe
18 11.69
251.56
251.84
0.18
0.00
4.37
0.37
252.43
254.33
252.d3
OK
1.90
0.00
0
0.55%
6923
Vas
0
&20621
]mnam
fatsa9ospw.-BbitC s
ExM1ibd CS
Exhibit F
Hydraulic Grade Lines
- 272 272 — — — - 272
202W
F!5
8
8
2W
2M
6
,
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