HomeMy WebLinkAboutExecutive SummaryOWNER
Dr. Ketan Sukkawala
Nivas Holdings, LP
17290 Eagle Pass Dr.
College Station, Texas 77845
979 -450 -1116, sukkawala@gmail.com
SUBMITTAL DATE: January 2012
GATTISENGINEERING
ENGINEERS • CONSULTANTS
EXECUTIVE SUMMARY REPORT
Rock Prairie Professional Office Complex
1103 Rock Prairie Rd., Ste #101
College Station, Texas
January 2012
PART 1.1
PROJECT ENGINEER
Joe I. Gattis, PE #90964, Project Engineer
GATTIS Engineering, LLC, Firm #7698
2010 Moses Creek Ct., College Station, Texas 77845
979 -575 -5022, joe@gattisengineering.com
PART 1.2
The SCOPE of this project consists of the re- platting of Tract `A -1' into three lots and the development of
Lot 1 into a professional office building site. Lots 2 and 3 will be developed into professional office sites
in the future.
PART 1.3
The Rock Prairie Professional Office Complex project (Tract `A -1) is located at 1103 Rock
Prairie Road in College Station. It is a part of a larger, multi -tract development from 1993
called the Southwood Living Center' The project property is 2.763 acres and is located in the
Bee Creek Drainage Basin. The property is located in the unshaded Flood Zone `X', outside of
the 500yr floodplain, as shown on FIRM Map #48041C0182 C, dated July 2, 1992. There are no
drainage ways or creeks that pass along or through this tract of land.
PART 1.4
The Project Tract is vacant with only native grasses and a few trees on site. The site is relatively
flat with grades between 1% and 2 %. It has a slight crown in the middle that causes sheet flow
run -off in multiple directions. The stormwater un-off sheet flows to the North into an existing,
shared detention facility, to the East into the shared, private drive storm sewer system, and to the
south into the Rock Prairie Road storm sewer system.
In 1993, the stormwater mitigation for this multi -tract development was designed by Hester
Engineering. This design consists of shared detention facility, a private drive and its associated
storm sewer system. All stormwater run-off to all directions was accounted for in this 1993
design.
PART 1.5
As stated above, the stormwater run -off of Lots 1, 2 and 3 from the re -plat of Tract `A -1' has
been accounted for by the 1993 Drainage Design by Hester Engineering. With the curtrent
development of Lot 1 in the Rock Prairie Professional Office Complex Project, these storm water
parameters have been maintained.
Inside Lot 1, the stormwater run -off shall sheet flow to the surrounding parking lot areas,
captured by grate inlets, and conveyed to the existing storm sewer system along the shared
private drive. All roof drainage shall be captured via a roof gutter system and conveyed to the
grate inlet boxes by under - ground storm pipe.
PART 1 ? 6 ,
The storm water drainage for this site was designed in 1993, and its original intent was
maintained with this re -plat and new development. There are no new or special permitting
requirements associated with any local, state or federal agency. This project requires only a
Development Permit to be issued by the City of College Station.
PART 1.7
There is currently an approved drainage design titled Southwood Living Center' 1993 by Hester
Engineering on file at the City of College Station Development Services Department for this site.
For this development, an additional drainage report was provided to re -affirm the original design
assumptions, calculations and also the drainage design for each individual lot.
For this project, please see DRAINAGE SUMMARY REPORT, for the `Rock Prairie
Professional Office Complex' for a complete hydraulic analysis and design for the development
of Lot 1. This report consists of 94 pages of hydraulic analysis, calculations and summary with 4
drawings dated January 2012.
Respectfully,
GATTIS ENGINE NG, LLC
Joe • s, PE
Li • - ., ed Professional Engineer
AO; 4
JOE I. GATTIS
o 9 • : • ( 90964 0 : :Cr
��` C E N S isOf
\SS �=
FIRM # 7698 • 2010 Moses Creek Ct. • College Station, Texas 77845 • Tel. 979. j .5022 • Fax 979.690.6888
Part 2 — Project Administration
Start (Page 2.1)
Engineering and Design Professionals Information
Engineering Firm Name and Address:
GATTIS Engineering, LLC
20 I 0 Moses Creek Ct.
College Station, Texas 77845
Jurisdiction
City: Bryan
College Station
Date of Submittal:
February 14, 201 2
Lead Engineer's Name and Contact Info.(phone, e fax):
Joe Gattis, PE #90964; 979 - 575 -5022
Joe @gattisengineering.com
Other:
none
Supporting Engineering / Consulting Firm(s):
None
Other contacts:
None
Developer / Owner I Applicant Information
Developer / Applicant Name and Address:
Phone and e-mail:
Property Owner(s) if not Developer / Applicant (& address):
Dr. Ketan Sukkawala
1 7290 Eagle Pass Drive, CS, Tx 77845
Phone and e-mail:
979 -450 - I 1 16
Project Identification
Development Name: Rock Prairie Professional Office Complex
Is subject property a site project, a single -phase subdivision, or part of a multi -phase subdivision?
Multi - Phase Subdivision If multi - phase, subject property is phase _1_ of _3_
Legal description of subject property (phase) or Project Area:
(see Section II, Paragraph B -3a)
Lot 1(0.828 ac) of 3 of Southwood holdings Re -Mat of Tract 'A- I ' (2.763 ac)
1 103 Rock Prairie Road, Ste# I 01 , College Station, Texas 77845
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.
This is the first phase.
General Location of Project Area, or subject property (phase):
1 1 03 Rock Prairie Road next to Fortress health $ Rehab
In City Limits?
Bryan: acres.
Extraterritorial Jurisdiction (acreage):
Bryan: College Station:
College Station: 2.763 acres.
Acreage Outside ETJ:
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 3 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 2 — Project Administration
Continued (page 2.2)
Project Identification (continued)
Roadways abutting or within Project Area or
subject property:
Rock Prairie Road
Abutting tracts, platted land, or built
developments:
The Esperanza of College Station
Fortress Health $ Rehab
Named Regulatory Watercourse(s) & Watershed(s):
None
Tributary Basin(s):
Bee Creek Drainage Basin
Plat Information For Project or Subject Property (or Phase)
Preliminary Plat File #: unknown
Final Plat File #: unknown Date:
Status and Vol /Pg: V 7953 / Pg 025
Name:
If two plats, second name: Not Applicable File #:
Status: Date:
Zoning Information For Project or Subject Property (or Phase)
Zoning Type: A/P Existing or Proposed? Existing Case Code:
Case Date Status:
Zoning Type: Existing or Proposed? Case Code:
Case Date Status:
Stormwater Management Planning For Project or Subject Property (or Phase)
Planning Conference(s) & Date(s):
Project Discussion, March 201 I
Participants:
Josh Norton, Morgan Hester
Preliminary Report Required? No Submittal Date Jan 15, 201 I Review Date I - 1 - 20 12
Review Comments Addressed? Yes X No In Writing? X When? 02 I G - 2
Compliance With Preliminary Drainage Report. Briefly describe (or attach documentation
explaining) any deviation(s) from provisions of Preliminary Drainage Report, if any.
Previous Drainage Report was completed and approved in January 1 993. This 'New'
report is an addendum. This addendum summary report evaluates and confirms original
drainage designs $ assumptions to confirm that this new development conforms to original
1 993 drainage parameters.
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 4 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 2 — Project Administration
Continued (page 2.3)
Coordination For Project or Subject Property (or Phase)
Note: For any Coordination of stormwater matters indicated below, attach documentation
describing and substantiating any agreements, understandings, contracts, or approvals.
Coordination
With Other
Departments of
Jurisdiction
City (Bryan or
College Station)
Dept.
Contact:
Date:
Subject:
Coordination With
Non - jurisdiction
City Needed?
Yes No X
Summarize need(s) & actions taken (include contacts & dates):
Coordination with
Brazos County
Needed?
Yes No X
Summarize need(s) & actions taken (include contacts & dates):
Coordination with
TxDOT Needed?
Yes No X
Summarize need(s) & actions taken (include contacts & dates):
Coordination with
TAMUS Needed?
Yes No X
Summarize need(s) & actions taken (include contacts & dates):
Permits For Project or Subject Property (or Phase)
As to stormwater management, are permits required for the proposed work from any of the entities
listed below? If so, summarize status of efforts toward that objective in spaces below.
Entity
Permitted or
?
Status of Actions include dates)
Actions ( include
US Army Crops of
Engineers
No X Yes
US Environmental
Protection Agency
No X Yes
Texas Commission on
Environmental Quality
No X Yes
Brazos River
Authority
No X Yes
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 5 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
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?
Development of vacant lot into 5,945 scj ft office bldg $ associated parking lot area
Site
Development
Project
(select all
applicable)
+ Redevelopment of one platted lot, or two or more adjoining platted Tots.
Building on a single platted lot of undeveloped land.
_X_
Building on two or more platted adjoining lots of undeveloped land.
Building on a single lot, or adjoining lots, where proposed plat will not form
a new street (but may include ROW dedication to existing streets).
Other (explain):
Subdivision
Development
Project
Construction of streets and utilities to serve one or more platted lots.
Construction of streets and utilities to serve one or more proposed lots on
lands represented by pending plats.
Describe
Nature and
Size Of
Proposed
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
drainage easements or ROW.
Proposed 5,495 sci ft medical office building, with parking
Impervious Cover ratio is approximately 80%
Project
Is any work planned on land that is not platted
If yes, explain:
or on land for which platting is not pending?
X No Yes
FEMA Floodplains
Is any part of subject property abutting a Named Regulatory Watercourse
(Section II, Paragraph B1) or a tributary thereof?
No X Yes
Is any part of subject property in floodplain
area of a FEMA - regulated watercourse?
No X Yes Rate Map
Encroachment(s)
into Floodplain
areas planned?
No X
Encroachment purpose(s): Building site(s) Road crossing(s)
Utility crossing(s) Other (explain):
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.
Not Applicable
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 6 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 3 — Property Characteristics
Continued (Page 3.2)
Hydrologic Attributes of Subject Property (or Phase)
Has an earlier hydrologic analysis been done for larger area including subject property?
Yes
X
Reference the study (& date) here, and attach copy if not already in City files.
Drainage Analysis, Southwood Living Center, 1 2.44 ac, Jan. 1 993 by Hester Engineering
Is the stormwater
earlier study?
management plan for the property in substantial
Yes x No If not, explain how
conformance with the
it differs.
No
If subject property
plan for the property
is not part of multi -phase project, describe
stormwater management
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
Describe them (include approximate size, volume, outfall, model, etc).
A portion of the shared detention facility
'A -1'. Total capacity = 66,189 c.f., 14"
orifi
runoff? No X Yes
is on Tract
w x 37" tall
Any known drainage or flooding problems in areas near subject property?
Identify:
X No Yes
Based
(see Table
X
on location of
B -1 in Appendix
Detention is required.
study property in a watershed, is Type 1 Detention (flood control) needed?
B)
Need must be evaluated. Detention not required.
If the need for
Type 1 Detention
must be evaluated:
What decision has been reached? By whom?
Detention will be provided; City College Station $ Gattis Engineering
How was determination made?
The decision is based on maintaining existing drainage design from 1 993.
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 7 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
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?
describe splits below. In Part 4 describe design concept
X No Yes If yes,
for handling this.
Watershed or Basin
Larger acreage
Lesser acreage
Above - Project Areas(Section II, Paragraph B3 -a)
Does Project Area (project or phase) receive runoff from upland areas?
Size(s) of area(s) in acres: 1) 2) 3)
X No Yes
4)
Flow Characteristics (each instance) (overland sheet, shallow
concentrated, recognizable
Watercourse or tributary);
concentrated section(s), small creek (non - regulatory), regulatory
Flow determination: Outline hydrologic methods and assumptions:
Does storm runoff drain from public easements or ROW
No Yes If yes, describe facilities in easement
onto or across subject property?
or ROW:
Are changes in runoff characteristics subject to change in future? Explain
Conveyance Pathways (Section II, Paragraph C2)
Must runoff from study property drain across lower properties before reaching a Regulatory
Watercourse or tributary? No X Yes
Describe length and characteristics of each conveyance pathway(s). Include ownership of
property(ies).
Outfall of Detention Pond flows through established drainage easement through the
Southwood Forest Ph 4 Subdivision
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 8 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 3 — Property Characteristics Continued (Page 3.4)
Hydrologic Attributes of Subject Property (or Phase) (continued)
Conveyance Pathways (continued)
Do drainage
easements
exist for
part of
pathway(s)?
X No
any
If yes, for what part of length? % Created by? plat, or
instrument. If instrument(s), describe their provisions.
Yes
Pathway
Areas
Where runoff must cross lower properties, describe characteristics of abutting lower
property(ies). (Existing watercourses? Easement or Consent aquired ?)
Not Applicable
Nearby
Drainage
Facilities
Describe any built or improved drainage facilities existing near the property (culverts,
bridges, lined channels, buried conduit, swales, detention ponds, etc).
The detention facility outfall structure meter - releases stormwater downstream
via a 36" diameter culvert under the shared private drive.
Do any of
design?
these have hydrologic or hydraulic influence on proposed stormwater
X No Yes If yes, explain:
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 9 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
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.
Not Applicable
Discharge(s) To Lower Property(ies) (Section II, Paragraph El)
Does project include drainage features (existing or future) proposed to become public via
platting? X No Yes Separate Instrument? X No Yes
Per Guidelines reference above, how will
runoff be discharged to neighboring
property(ies)?
Establishing Easements
(Scenario 1)
Release (Scenario 2)
of the two Scenarios
X Pre - development
Combination
Scenario 1: If easements are proposed, describe
where needed, and provide status of actions
on each. (Attached Exhibit # )
Not Applicable
Scenario 2: Provide general description of how
release(s) will be managed
etc.). (Attached
easements from 1 993
to pre - development
Exhibit # )
conditions (detention, sheet flow, partially concentrated,
Detention Facility has established drainage
design
Combination: If combination is proposed, explain
how discharge will differ from pre -
each area (or point) of release.
development conditions at the property line for
Not Applicable
If Scenario 2 or Combination are to be used,
has proposed design been
No X Yes Explain
coordinated with
and provide
into Harvey
owner(s) of receiving property(ies)?
documentation.
Design will maintain existing drainage design of stormwater outfall
Road Storm Sewer System.
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 10 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.2)
Stormwater Management Concept (continued)
Within Project Area Of Multi -Phase Project
Will project result
in shifting runoff
between Basins or
between
Watersheds?
X No
Identify gaining Basins or Watersheds and acres shifting:
Not Applicable
What design and mitigation is used to compensate for increased runoff
from gaining basin or watershed?
Not Applicable
Yes
How will runoff from Project
Area be mitigated to pre-
development conditions?
Select any or all of 1, 2,
and /or 3, and explain below.
1. _X_ With facility(ies) involving other development projects.
2 Establishing features to serve overall Project Area.
3. On phase (or site) project basis within Project Area.
1. Shared facility (type & location of facility; design drainage area served; relationship to size of
Project Area): (Attached Exhibit # 1 )
The existing shared detention facility and easements was designed in 1 993.
Its watershed area is approximately 1 2.57ac. See Attachement #i
2. For Overall Project Area (type & location of facilities): (Attached Exhibit # )
3. By phase (or site) protect: 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?
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
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 11 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept 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 size and In which phase(s).
Not Applicable
If detention /retention serves (will serve) overall Project Area, describe how it relates to subject
phase or site project (physical location, conveyance pathway(s), construction sequence):
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? 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?
ditches use
Yes
Steepest side slopes:
Usual front s opes:
Usual back slopes:
Flow line slopes: least
Typica distance from travelway:
(Attached Exhibit # )
typical greatest
Are longitudinal culvert ends in compliance with B -CS Standard Specifications?
Yes No, then explain:
At intersections or otherwise, do valley gutters cross arterial or collector streets?
No Yes If yes explain:
Bets with cL
;utter used
Jo
Are valley gutters proposed to cross any street away from an intersection?
No Yes Explain: (number of locations ?)
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 12 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.4)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Are streets with curb and gutter used?
(continued)
Gutter line slopes: Least Usual Greatest
Are inlets recessed on arterial and collector streets? Yes No If "no ",
identify where and why.
Will inlets capture 10 -year design stormflow to prevent flooding of intersections (arterial
with arterial or collector)? Yes No If no, explain where and why not.
Will inlet size and placement prevent exceeding allowable water spread for 10 -year
design storm throughout site (or phase)? Yes No If no, explain.
Saq curves: Are inlets placed at low points? Yes No Are inlets and
conduit sized to prevent 100 -year stormflow from ponding at greater than 24 inches?
Yes No Explain "no" answers.
Will 100 -yr stormflow be contained in combination of ROW and buried conduit on
whole length of all streets? 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.
Is storm drain system used?
No x Yes
Are any 12 -inch laterals used? X No Yes Identify length(s) and where
used.
Pipe runs between system
access points (feet):
Typical Longest
Are junction boxes used at each bend? Yes X No If not, explain where
and why.
There is a private drainage system along the private drive that has a
36" diameter 45degree bend - designed 1 993
Are downstream soffits at or below upstream soffits?
Yes X No If not, explain where and why:
Least amount that hydraulic
grade line is below gutter line
(system- wide):
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 13 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.5)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Storm drain system (continued)
(on separate sheet provide same info. for more instances)
Outfall(s)
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?
2) Watercourse (or system), velocity, and angle?
3) Watercourse (or system), velocity, and angle?
For each ouffall above, what measures are taken to prevent erosion or scour of
receiving and all facilities at juncture?
1)
2)
3)
Are swales used to drain streets?
x No Yes
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 slopes (minimum and maximum):
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:
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 14 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.6)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Roadside Ditches
Are roadside ditches used? X No Yes If so, provide
the following:
? Yes No
Is 25 -year flow contained with 6 inches of freeboard throughout
Are top of banks separated from road shoulders 2 feet or more?
Are all ditch sections trapezoidal and at least 1.5 feet deep?
Yes No
Yes No
For any "no" answers provide location(s) and explain:
(on separate sheet provide same information for any additional instances)
1
If conduit is beneath a swale, provide the following information (each instance).
Instance 1 Describe general location,
approximate length:
Is 100 -year design flow contained in conduit/swale combination?
If "no" explain:
Yes No
Space for 100 -year storm flow? ROW Easement Width
Swale Surface type, minimum
Conduit Type and size, minimum
and maximum
and maximum slopes:
slopes, design storm:
Inlets Describe how conduit is loaded
(from streets /storm drains, inlets by type):
Access Describe how maintenance
access is provided (to swale, into conduit):
Instance 2 Describe general location,
approximate length:
Is 100 -year design flow contained in conduit/swale combination?
If "no" explain:
Yes No
Space for 100 -year storm flow? ROW Easement Width
Swale Surface type, minimum
Conduit Type and size, minimum
and maximum
and maximum slopes:
slopes, design storm:
Inlets Describe how conduit is loaded
(from streets /storm drains, inlets by type):
Access Describe how maintenance
access is provided (to swale, into conduit):
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 15 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.7)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Will swales without buried conduit receive runoff from
public ROW or easements? x No Yes. Explain
If "yes" provide the following information for each instance:
Instance 1 Describe general location, approximate length, surfacing:
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 provide:
Instance 2 Describe general location, approximate length, surfacing:
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.
Channel improvements proposed?
x No Yes Explain
"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.
Will design replicate natural channel? Yes No If "no ", for each instance
describe section shape & area, flow line slope (min. & max.), surfaces, and 100 -year
design flow, and amount of freeboard:
Instance 1:
Instance 2:
Instance 3:
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 16 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.8)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Channel Improvements (continued)
Existing channels (small creeks): Are these used? X No Yes
If "yes" provide the information below.
Will small creeks and their floodplains remain undisturbed? Yes No How
many disturbance instances? Identify each planned
location:
For each location, describe length and general type of proposed improvement
(including floodplain changes):
For each location, describe section shape & area, flow line slope (min. & max.),
surfaces, and 100 -year design flow.
Watercourses (and tributaries): Aside from fringe changes,
are Regulatory
Explain below.
Watercourses proposed to be altered? X No Yes
Submit full report describing proposed changes to Regulatory
existing and proposed section size and shape, surfaces, alignment,
length affected, and capacity, and provide full documentation
and data. Is full report submitted? Yes No
Watercourses. Address
flow line changes,
of analysis procedures
If "no" explain:
All Proposed Channel Work: For all proposed channel work,
provide information
requested in next three boxes.
If design is to replicate natural channel, identify location and length here, and describe
design in Special Design section of this Part of Report.
Not Applicable
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
Yes No If not, identify location(s) and explain:
maintenance space?
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 17 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.9)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
1_
How many facilities for subject property project? 1 For each provide info. below.
For each dry -type facilitiy:
Faci
ity 1
Faci
ity 2
Acres served & design volume + 10%
14.Oac
42, I 23cf
100 -yr volume: free flow & plugged
42, 1 23cf
82,585
Design discharge (10 yr & 25 yr)
25.9cfs
27.5cfs
Spillway crest at 100 -yr WSE?
Berms 6 inches above plugged WSE?
Explain any "no" answers:
I00 year W.S.E. = 3 I 7.93',
Spillway W.S.E. (Top of Curb)
Existing Facility Designed in 1
yes X no
yes no
yes X no
yes no
Top of Pond =3 1 9.00'
= 3 1 9.50' - flow over private
993
drive to channel
For each facility what is 25 - yr design Q, and design of outlet structure?
Facility 1: 27.5cfs, Orifice Box with 14" x 37" opening
Facility 2:
Do outlets and spillways discharge into a public facility in easement or ROW?
Facility 1: X Yes No Facility 2: Yes No
If "no" explain:
Facility Outfall discharges into existing drainge easement/channel
through Southwood Forest, Phase 4
For each, what is velocity of 25 -yr design discharge at outlet? & at spillway?
Facility 1: 3.9 fps & none Facility 2: &
Are energy dissipation measures used? X No Yes Describe type and
location:
For each, is spillway surface treatment other than concrete? Yes or no, and describe:
Facility 1: No, concrete channel
Facility 2:
For each, what measures are taken to prevent erosion or scour at receiving facility?
Facility 1: Concrete Channel
Facility 2:
If berms are used give heights, slopes and surface treatments of sides.
Facility 1: No Grass Berms, 3: I Sloped walls; Top Elev =3 1 9.00'
Max Depth = 5.5'
Facility 2:
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 18 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.10)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Detention Facilities
(continued)
Do structures comply with B -CS Specifications? Yes or no, and explain if "no ":
Facility 1; Yes
Facility 2:
For additional facilities provide all same information on a separate sheet.
Are parking areas to be used for detention? X No Yes What is
maximum depth due to required design storm?
Are culverts used at private crossings?
No X Yes
Roadside Ditches: Will culverts serve access driveways at roadside ditches?
X No Yes If "yes ", provide information in next two boxes.
Will 25 -yr. flow pass without flowing over driveway in all cases? Yes No
_X_
Without causing flowing or standing water on public roadway? Yes No
_X_
Designs & materials comply with B -CS Technical Specifications? Yes No
_X_
Explain any "no" answers:
Are culverts parallel to public roadway alignment? Yes No Explain:
_X_
36" culvert crosses underneath private drive
Creeks at Private Drives: Do private driveways, drives, or streets cross drainage
ways that serve Above - Project areas or are in public easements/ ROW?
X No Yes If "yes" provide information below.
How many instances? Describe location and provide information below.
Location 1:
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.
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 19 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.11)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
(for more instances of any type describe location and same information on separate sheet) J
Named Regulatory Watercourses (& Tributaries): Are culverts
proposed on these
assumptions,
support proposed
", explain:
facilities? No Yes, then provide full
report documenting
that
If "no
criteria, analysis, computer programs, and study findings
design(s). Is report provided? Yes No
Arterial or Major Collector Streets: Will culverts
serve these
types of roadways?
For each identify the
No Yes How many instances?
location and provide the information below.
Instance 1:
Instance 2:
Instance 3:
Yes or No for the 100 -year design flow:
1
2
3
Headwater WSE 1 foot below lowest curb top?
Spread of headwater within ROW or easement?
Is velocity limited per conditions (Table C -11)?
Explain any "no" answer(s):
Minor Collector or Local Streets: Will culverts serve
these types
for
of streets?
each identify the
No Yes How many instances?
location and provide the information below:
Instance 1:
Instance 2:
Instance 3:
For each instance enter value, or "yes" I "no" for:
1
2
3
Design yr. headwater WSE 1 ft. below curb top?
100 -yr. max. depth at street crown 2 feet or less?
Product of velocity (fps) & depth at crown (ft) = ?
Is velocity limited per conditions (Table C -11)?
Limit of down stream analysis (feet)?
Explain any "no" answers:
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 20 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.12)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Culverts (continued)
All Proposed Culverts: For all proposed culvert facilities (except
driveway /roadside
boxes.
ditch intersects) provide information requested in next eight
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
approaches thereto? No Yes If "yes" identify location(s),
culvert and surfaced
describe
change(s), and justification:
Are flumes or conduit to discharge into culvert barrel(s)? No Yes If yes,
identify location(s) and provide justification:
Are flumes or conduit to discharge into or near surfaced approaches
No Yes If "yes" identify location(s), describe
to culvert ends?
outfall design treatment(s):
Is scour /erosion protection provided to ensure long 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 backwater be fully contained
drainage easements/ ROW? Yes No if not, why
in street ROW, and /or
not?
Do appreciable hydraulic effects of any culvert extend downstream
neighboring land(s) not encompassed in subject property?
"yes" describe location(s) and mitigation measures:
or upstream to
No Yes If
Are all culvert designs and materials in compliance with B -CS
Yes No If not, explain in Special Design Section
Tech. Specifications?
of this Part.
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 21 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.13)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Bridge(s)
Is a bridge included in plans
If "yes" provide the following
for subject property project? X No Yes
information.
Name(s) and functional classification of the roadway(s)?
What drainage way(s) is to be crossed?
A full report supporting all aspects of the proposed bridge(s)
hydrologic, and hydraulic factors) must accompany this summary
provided? Yes No If "no" explain:
(structural, geotechnical,
report. Is the report
Water Quality
Is a Stormwater
Pollution Prevention
Plan (SW3P)
established for
project construction?
No X Yes
Provide a general description of planned techniques:
I) Silt Fencing Around All Dirt Work
2) Sand Bags around exitsing inlet grate
3) Silt Fence $ hay Bale Combo at Spillway
Special Designs — Non - Traditional Methods
Are any non - traditional methods
replication, BMPs for water quality,
X No Yes If "yes" list
(aquatic echosystems, wetland -type detention, natural stream
etc.) proposed for any aspect of subject property project?
general type and location below.
Provide full report about the proposed
expected benefits. Report must
be compromised, and that maintenance
solution(s). Is report provided?
special design(s) including rationale
substantiate that stormwater management
cost will not exceed those of
Yes No If "no" explain:
for use and
objectives will not
traditional design
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 22 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
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
B -CS Technical Specifications, check type facility(ies) and explain by
Detention elements Drain system elements
deviate from provisions of
specific detail element.
Channel features
Inlets Outfalls
Culvert features Swales Ditches
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
Briefly summarize the range of applications made of the Rational Formula:
The Rational Metod was used to evaluate the watershed basin for existing detention
pond facility. The Rational Method was alsoused to develop hydrographs for PERVIOUS and
IMPERVIOUS surfaces and produce an estimated stormwater run -off for Lot I . These
surfaces included roof drainage, paved parking lot, and landscaped areas.
What is the size and location of largest
has been applied? 4.G acres
Design Drainage Area to which the Rational Formula
Location (or identifier): Episcopal Church Tract
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 23 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.15)
Design Parameters (continued)
Hydrology (continued)
In making determinations for time of concentration, was segment analysis used?
No X Yes In approximately what percent of Design Drainage Areas? 70 %
As to intensity- duration - frequency and rain depth criteria for determining runoff flows, were any
criteria other than those provided in these Guidelines used? X No Yes If "yes"
identify type of data, source(s), and where applied:
For each of the stormwater management features listed below identify the storm return
frequencies (year) analyzed (or checked), and that used as the basis for design.
Feature
Analysis Year(s)
Design Year
Storm drain system for arterial and collector streets
N/A
Storm drain system for local streets
N/A
Open channels
N/A
Swale /buried conduit combination in lieu of channel
N/A
Swales
N/A
Roadside ditches and culverts serving them
N/A
Detention facilities: spillway crest and its outfall
2,5, 1 0,25,50, 100
100
Detention facilities: outlet and conveyance structure(s)
2,5, 1 0,25,50, 100
100
Detention facilities: volume when outlet plugged
100
100
Culverts serving private drives or streets
N/A
Culverts serving public roadways
N/A
Bridges: provide in bridge report.
N/A
Hydraulics
What is the range of design flow velocities as outlined below?
Design flow velocities;
Gutters
Conduit
Culverts
Swales
Channels
Highest (feet per second)
Lowest (feet per second)
Streets and Storm Drain Systems Provide the summary information outlined below:
Roughness coefficients used: For street gutters: n=0.013
For conduit type(s) RCP Coefficients: n=0.013
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 24 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.16)
Design Parameters (continued)
Hydraulics (continued)
Street and Storm Drain Systems (continued)
For the following, are assumptions other than allowable per Guidelines?
Inlet coefficients? X No Yes Head and friction losses X No Yes
Explain any "yes" answer:
In conduit is velocity generally increased in the downstream direction?
Are elevation drops provided at inlets, manholes, and junction boxes?
Explain any "no" answers:
Yes
No
_X_
Yes
No
_X_
Are hydraulic grade lines calculated and shown for design storm? X Yes No
For 100 -year flow conditions? X Yes No Explain any
"no" answers:
What tailwater conditions were assumed at outfall point(s) of the storm drain system?
each location and explain:
Not Applicable
Identify
Open Channels If a HEC analysis is utilized, does it follow Sec VI.F.5.a?
Yes
No
Outside of straight sections, is flow regime within limits of sub - critical
If "no" list locations and explain:
Not Applicable
flow? Yes
No
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?
Not Applicable
Entrance, friction and exit losses:
Bridges Provide all in bridge report
Not Applicable
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 25 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
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
* AutoCad Land Desktop 2005, Civil Design 2005;
* hydraFlow hydragraphs 2007, hydraflow Express 2007
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:
In the re -plat of Tract 'A- I ' and development of Lot I , I verified that the existing detention
pond and storm sewer conduit system will perform as originally designed in 1 993
and to meets the standards as set forth in the D /CS Unified Drainage Design Guidelines.
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
by me (or under my supervision) in accordance with provisions of the
Unified Drainage Design Guidelines for the owners of the property. All
required by any and all sf to and federal regulatory agencies for the
improvements r ave be- ,'ssued or fall under applicable general permits."
(Affix Seal)
Part B was prepared
Bryan /College Station
licenses and permits
proposed drainage
+``a`O
.. (E OF 7z %
* *• ��� r * ��
JOE I. GATTIS A
. /
�, 90964 ••2- ff
Licen if 'rofessional Engineer
State o Texas PE No. 9 / 6
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 26 of 26 APPENDIX. D: TE . DESIGN SUMMARY
A vised February 2009
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