Loading...
HomeMy WebLinkAboutSummary Reportt .. •' Bleyl & Associates Project Engineering & Management April 16, 2010 Erika Bridges, E. I .T. Planning and Development Services City of College Station P 0 Box 9960 College Station, TX 77842 RE: Executive Summary Report Entergy Site Plan Dear Erika, 1 722 Broadmoor Suite 210 Bryan, TX 77802 As required by the City of College Station, Bleyl and Associates has prepared a Stormwater Management Technical Design Summary Report for submission and review for the referenced project. This report includes the Executive Summary Report, a completed Technical Design Summary, and other reference material needed for your review. CONTACT INFORMATION 1. ENGINEER: Mark A. Savarino, P.E. Bleyl & Associates 1722 Broadmoor Drive Suite 210 Bryan, Texas 77802 2. OWNER: Charles Eric Jones 10998 Nunn Jones Rd College Station, Texas 77845 3. SUBM ITTAL DATE: April 19, 2010 (2nd Submittal) GENERAL PROJECT INFORMATION The owner wishes to build an electrical switch station for Entergy, Inc. as well _as associated improvements including a crushed limestone base driveway and landscaping . The property is 16.615 acres however the proposed improvements will affect approximately 3.96 acres of the property. There are no additional phases planned. Bryan (979)-268-1125 (979)-260-3849 Austin (512)-328-7878 (512)-328-7884 Fax Conroe (936 )-441-7833 (936)-760-3833 Fax ' ( PROJECT LOCATION The proposed 16.615 acre project site is located on Switch Station Rd. approximately 1,000 feet northeast of the intersection of Appomattox Dr. and Switch Station Rd. The entire property falls within the city limits of College Station . The property is within the Carter's Creek Watershed. The northeastern property line of the tract is approximately 700 feet west of Carter's Creek. Because of its proximity to a primary channel, no detention is proposed . Due to the project being constructed within the floodplain , a No Adverse Impact Study has been completed for the site by Mitchell and Morgan. The study is provided under a separate cover. HYDROLOGIC CHARACTERISTICS Land cover on the property is mostly a dense Buffalo or prairie grass with a few scattered trees. The western side of the site is approximately sixteen feet higher than the eastern half and allows for existing runoff to sheet flow from west to east in a shallow concentrated manner. This flow crosses the neighboring tract to the east currently owned by the developer of this property. The subject property is bounded by a 77 acre tract owned by Richard Smith to the northwest, a 22 acre tract owned by Carl and Jeannie Kolbe to the southeast, a 2 acre tract owned by Oakwood Custom Homes to the south, and the existing City of College Station Switch Station to the southwest. Of these areas, runoff on site is generally received from the existing switch station site and the Richard Smith site and sheet flows in an easterly direction before exiting the site and entering Carter's Creek. This project will entai l the construction of an approximate 2.48 acre limestone rock pad and switch station over the existing prairie grass surface as well as filling in an existing watering tank used for cattle. These will be the basis of the post developed flow calculations. STORMWATER MANAGEMENT Due to the proximity of the site to Carter's Creek, no detention of runoff is requested for this site . Based on this request, our stormwater plan is to essentially convey runoff across the developed site in a sheet flow I shallow concentrated manner and , after exiting the developed area, allow it to continue to be conveyed as was originally occurring. After flowing across the downstream property, the stormwater will enter Carter's Creek to the east. Pre-and post-developed flow rates have been calculated using initial assumptions wh ich include runoff efficients of 0.33 for unimproved pasture land and manicured grass land (park) (low range for average slopes), 1.0 for impervious pond areas, and 0.40 for the limestone rock used to create the pad for the switch station site. Time of concentration calculations are based on segment analysis . Based on these considerations, the pre-developed and post-developed discharge rates are estimated as follows: { \ Pre (cfs) 0 2 10.45 0 10 14.80 0 2s 16.99 Oso 19.31 0100 20.17 Post (cfs) 10.82 15.29 17.56 19.96 20 .84 Due to the slight increase in flow in the post developed conditions, we request the direct conveyance of this stormwater. Also, as previously mentioned, because of the proximity of the site to Carter's Creek and being inside of the creek's floodplain limits, a No Adverse Impact Study has been prepared by Mitchell and Morgan. Within this study, it was concluded that, with the use of the proposed compensatory storage provided to the northeast of the pad, the filling within the floodplain to construct the pad will not adversely impact the downstream base flood elevation. REFERENCE This Summary Report, a one 26-page design summary dated April 16, 2010, and additional exhibits comprise the drainage report for this project. A copy of the Mitchell and Morgan "No Adverse Impact" Study is provided under a separate cover. Please contact me with any questions, or if you require any additional information to complete your technical review of this project. Sincerely, Wef-:-- Mark Savarino, P.E. Project Manager __ ,,,,,,,, -~~OFr~'\\ ;.-1.'i!-······· ,, "'~ ...... ••• ••• \$\ • I*.-· · .. * •t ,... · ... ~ Ir ••• ~: •••••••••••••••••••••••• ~ f MARK A. SAVARINO ~ '·····························~ \ ~ ·• 105149 :' 15 J ftt'b.::..•t.!CtNS<c_,.~···§J; ,, ~~ • • • • • • • ...,w.G ,: . \\\"$/ONA\..""'":_: \\: --;<\.'''1 111.J-io•o , • I. • .. ~ l EXHIBIT A TECHNICAL DESllGN SUMMARY ~· .. SECTfON !X APPENDtX D -TECHNICAL DES IGN SUMMARY The Cities of Bryan and College Station both require storm drainage design to follow these Unified Stormwater Design Guidelines. Paragraph C2 of Section Il l (Administration) requires submittal of a drain age 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 111 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 necessa y. 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. l\Jame , 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, STORIVl\/VATER DESIG I\! GUIDC:Ll/\J ES Effective February 2007 Page 1 of 26 APPC:NDIX. D TECH. DESIGf\J SUl\~MARY P..s Revised Februarv 2009 .. SECTION· IX APPENDIX D -TECHNICAL DESI GN SUMMARY or clearing/grading perm its , as well as reference to any application numbers or codes assigned by the City to such request. 3. The location of the project should be described. This should identify the Named Regulatory Watershed(s) in which it is located , how the entire project area is situated therein, whether the property straddles a watershed or basin divide, the approximate acreage in each basin , and whether its position in the Watershed dictates use of detention design. The approximate proportion of the property in the city limits and within the ET J is to be identified, including whether the property straddles city jurisdictional lines . If any portion of the property is in floodplains as described in Flood Insurance Rate Maps published by FEMA that should be disclosed. 4. The hydrologic characteristics of the property are to be described in broad terms: existing land cover; how and where stormwater drains to and from neighboring properties; ponds or wetland areas that tend to detain or store stormwater; existing creeks, channels, and swales crossing or serving the property; all existing drainage easements (or ROW) on the property, or on neighboring properties if they service runoff to or from the property. 5. The general plan for managing storm water in the entire project area must be outlined to include the approximate size, and extent of use, of any of the foll owing features: storm drains coupled with streets; detention I retention facilities; buried conveyance conduit independent of streets; swales or channels; bridges or culverts; outfalls to principal watercourses or their tributaries; and treatment(s) of existing watercourses. Also, any plans for reclaiming land within floodplain areas must be outlined. 6. Coordination and permitting of stormwater matters must be addressed. This is to include any specialized coordination that has occurred or is planned with other entities (local, state, or federal ). This may include agencies such as Brazos County government, the Brazos River Authority, the Texas A&M ·university System, the Texas Department of Transportation, the Texas Commission for Environmental Quality, the US Army Corps of Engineers, the US Environmental Protection Agency, et al. Mention must be made of any permits, agreements , or understandings that pertain to the project. 7. Reference is to be made to the full drainage report (or the Technical Design Summary Report) which the executive summary represents. The principal elements of the main report (and its length), including any maps, drawings or construction documents, should be itemized . An example statement might be: "One __ -page drainage report dated construction drawings ( __ sheets) dated .one set of ----, and a ___ -page specifications document dated ___ _ comprise the drainage report for this project." STORIVIWATER DESIGN GUIDELINES Effective February 2007 Page 2 of 26 APPENDIX_ D: TECH. DESIGN SUMMARY As Revised FebruaD' 2009 ,.,. r • i SECTION rx APPEt\!DfX D -TECHNICAL DESIGN SUMMARY Part 2 -Proiect Administration I Start (Page 2.1) En~ineer'inQ and Design Professionals Information Engineering Firm l\Jame and Address: Jurisdiction "b \ c.~\ ~ A;.s otJ Q.lrc..s City: Bryan tl"l-1... 'bt"ert-d'"""c.e>f" \)I". .j College Station Ste.. 1...t D ~r' Lt c..Y.'\ r Ti '7'1SO"Z.-Date oi Submittal: 4114\ 11010 Other: Lead Engineer's l\Jame and Contact lnio.~hone, e-mail, fa>J ~ ~ ('t.1~'-i'L."'S,•11'-.~ ~ °l'. '\ft.Xfl".C<'\1 '?•C. ("\~A.Sa..v6-rlno?E ~s Ctt-i~'\ '?.i-o·3~"'4"'\ . -S"iM.: 1 fm10i1C • .'· ""'S.av ... l'1nc.~ bkv\c:.11'\1;1"'"-' ....... ~ ..... -Other contacts: Supporting Engineering I Consulting Firm(s): ~~"'"""''-\\ \ «\o'<"~ -N,, ~.i...ic.,.~ \-.~lo. ~'{ ::t"'oc.\. "'~\.lr._\r,.(..l\ -[ '\"'l'\) 1:.'""0• ''t"'""' pft, s ~ "S' --s;lt-c.. c:..n.6 ..... 5. <, E"ro'>\C>('\ (A.,....lm,.\ $w.o\ h1w.c:.dlt-C;..\\~· l"""t1:.} ">""l-1· ~'O'{O :;i" ..... .. ·~1· ·-. .., .DeN.el.oper;i/i.Gwnerf/ ,Applicantlnformation _.,, .. _ ·"· •' Developer I Applicant l\Jame and Address: Phone and e-mail: Ci-.._~ \cc; Ei:""i ~ :ro"''-,.. (~14-)-n~ ~ 'l~~~ '"'~S N~n"" ':re>""''-~ ~ Q.\"sc.. $W..~w.<n I~ i78ot~ Property Owner(s) if not Developer I Applicant (&address): Phone and e-mail: I ~,~ N/ft fPrq}ect~ldentification Development Name: E'l<i"rf;l:.fo. "{ $..Jt't'C.~ Sr-'l:'r~ c;."1, -Is subjecl property a siie project a single-phase subdivision, or parl of a mulii-phase subdivision? S~-k. '?l""C::Jcc_~ If multi-phase, subjec1 properiy is phase -of -Legal description of subjecl property (phase) or Project Area: (see Section II, Paragraph B-3a) L~·lllS" ~ "r""•·c:A Mc-i-r;..,.., i:.u..t-e. r U.S "--' i A -4 l. Co~\~~ $-T'-io O<"'. I "°Srt>.~~ Ca>'-'"-~ I -r Ct_:'-~ If subject property (phase) is second or laier phase of a project, describe general status of all earlier phases For most recenf earlier phase Include submittal and review dates. 1-JjA General Location of Project Area, or subject properiy (phase) A-f"?(""c,~al'I"'•~~ 11 ooc • ..,.!. E" p{' -¥•~ 1~rs.ce.+•cl\ t>f A~?C'""'·.-:. ~~ Cir.. ~ .. .d Swl~I,..., 4.-~~-°""' ~ . In City Limits? ! c}:traierritonal Jurisdiciion (acreage) Sryan -acres. i Bryan -College Station -College Siation IL.c.~lS-acres. .Acreage Ouiside ET J -STORM\f\lfa,TER DESIGl\I GUIDEUhJES Effective Februan1 2007 Page 3 ol 26 APPEl\IDIX. D TECH. DESIGl\I SUh~MARY .A.& Revised F ebruarv 2009 I I I H ---- ·-- .. SECTION rx APPENDIX D -TECHNICAL DESIGN SUMMARY Part 2 -Proiect Administration I Con~inued (page 2.2) Prqject Identification (continued) Roadways abutting or within Project Area or Abutting tracts, platted land, or built subject property: developme~: "5""" \ "rt.. h S-~lno"" ')?.d . '••·h~6we.o ?~.1i.1 c;.;.'i °" C.S 'Sw~k.\. S.~1• I\ -· ~ Erk ~~"!». 't>C"oe· 7:0 ». 's. - lt""i"'lC\ ~ 'lit~~ .. ~oo.i C.U~~ ~~ -P~Q -'3-o~~~ o (Ar..-\ ~ :r~n'~ t:..\•c. -?:t~ll -qns-' .. - Named Regulatory \l\~a!ercourse(s) & Watershed(s): Tributary Basin(s): ~~~y-'c,; Crc..t-~ NIA Plat Information JFor Prqjec.t or Sul?]ecLProperty {or Phas~:) .. .. -.· -PrelimiAary~Plat-File-#-: _IJ./,A -F-inal-Rla't-F-ile-#· . Date.: Name: Status and Vol/pg: If two plats, second name: ---File#: ... - Status: ;J /tt Date: ,.· .- 2orii ng 1lnlormati on For 1P_rqj ect m Subject Property :(or JPhase:~ . ·. .. .. . . . ..• .:--:·.-, .... ·---- Zoning Type: AD Existing or Proposed? e\:•~-h~ Case Code: ,.; /R Case Date l'J/P. Status: NJ~ .. ... --------7------------· ;;;r/ 14---· ·· --Zoning Type: N/A Existing or Proposed? ;.J f.f Case Code : Case Date N.J'"Pi Status: .. ·-. -----Stormwater 4Management Pfan~nin_.9 ;For 1PrQ.iecFor-Suoject-:P.r.ope~y {0r~Phas6,') ~----- Planning Conference(s) & Date(s): Participants: N/11 Nf A -----------.. --·-------1 -----------· -----------------= i Preliminary Report Required? >J/A Submittal Date Review Date I Review Comments Addressed? Yes l\Jo In Writing? When ? I ---- Compliance With Preliminary Drainage Report. Briefly describe (or attach documentation explaining) any deviation(s) from provisions of Preliminar11 Drainage Report, if any. N./~ STORMVVATER DESIGN GUIDELINES Effective February 2007 Page 4 of 26 APPEl\JDIX. D: TECH. DES/Gf\! SUlvl/l/iARY As Revised Februarv 2009 • t . -- . ---- .. SECTION !X APPEND!X D -TECHNI CAL DESIGN SUMMARY Part 2 -Proiect 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. Coordination Dept. Contact: Date: Subject: 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? Yes No ./ ---- Coordination wit~. Summarize need(s) & actions taken (include contacts & dates): TxDOT Neeqed? Yes No .,/ ' . ---- Coordination with Summarize need(s) & actions taken (include contacts & dates): TAIVlUS Needed? Yes No ~ ---- 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 ' Approved ? us Army Crops of Engineers No ..,/ Yes - US Environmental Protection Agency No .I Yes --- Texas Commission on Environmental Quality No ../ . Yes ---- Brazos River Authority No ./ Yes --- STORMWATER DESIGN GUIDELINES Effective February 2007 Page 5 of 26 Status of Actions (include dates) APPENDIX. D TECH . DESIGN SUMMARY As Revised February 2009 , SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 3 -ProQert~ Characteristics I Start (Page 3.1) Nature and Scope of Proposed Work Existing: Land proposed for development currently used, including extent of impervious cover? C'1 r t"CN\:\· \'f p-. ~w n. \o...a'\ d w \ \h 0•1. i .,.n pc.n1' °"s eo "'ur Site __ Redevelopment of one platted lot, or two or more adjoining platted lots. Development __{__Building on a single platted lot of undeveloped land. Project __ Building on two or more platted adjoining lots of undeveloped land. (select all __ Building on a single lot, or adjoining lots, where proposed plat will not form applicable) a new street (but may include ROW dedication to existing streets). __ Other (explain): Subdivision __ Construction of streets and utilities to serve one or more platted lots. Development __ Construction of streets and utilities to serve one or more proposed lots on Project lands represented by pending plats . Site projects: building use(s), approximate floor space, impervious cover ratio . Describe Subdivisions : number of lots by general type of use, linear feet of streets and Nature and drainage easements or ROW. Size of L•M.c.JS'-k>~ roc..\c. liU'\ci r-\p <A.~ ~ pf 'fproJhW\.~;L Pro12osed 2. ·'-'~ ~. Af+c..< CoW'\.Sff\M..-hoY"'\, p...d wi \\ ~ pc.rm.u-~ Project ~V-t.. 1 W\ ptx'lliou..S c:...ovtX ("~o \V\<XtA.~ \s o•/o. Is any work planned on land that is not platted If yes , explain: or on land for which platting is not pend ing? J No Yes ---- FEMA Floodplains Is any part of subject property abutting a Named Regulatory Watercourse I N __J_ y (Section II, Paragraph B1 ) or a tributary thereof? 0 es -- Is any part of subject property in floodplain I No_ Yes _L_ Rate Map ~604lC.OU~'\ 0 area of a FEMA-regulated watercourse? Encroachment( s) Encroachment purpose(s): _L_ Building site(s) __ Road crossing(s) into Floodplain areas planned? __ Utility cross ing(s) __ 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. Av5vs\ 4, 'U'.>d\ tJ IA ·, Y("c.l ~ '"' M"" 'I f\~tw"\ "!:.hows ~ t>V-CJU. .... \'~\'Y\\~ STORMWATER DESIGN GUIDELINES Effective February 2007 m...,, ~!>O~ lC..() l.'Z..O~ $\-c..cl ...,;~ . ..-\ ~ Page 6 of 26 .f\oodp ,.....:,"' . APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 , . I SECTION IX APPENDIX D -TEC HNI CAL DES IGN SUM MARY Part 3 -P ro~erty Characteristics I Contin ued (Page 3.2) Hydrologic Attributes of Subject Property (or Phase) Has an earlier hydrologic analysis been done for larger area including subject property? Yes Reference the study (&date) here, and attach copy if not already in City files. -- ' Is the stormwater management plan for the property in substantial conformance with the earlier study? Yes No If not, explain how it differs. No If subject property is not part of multi-phase project, describe stormwater management plan for the property in Part 4. __L_ 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). T"CKC. \ ~ 0..r"f"e..¥\..\\'f \ pond onsi+c. -.ppn>1t. o . lC\ cr.c. & "' s; -z.'" . T\o\.c. pon.d s~-re..~ w~.\-e.< ~,. ~t"\CA1~'..1 t>"'pose.s . \\-\\s ~ot'\d 1S pf"op~ obi:> 'x ~\\\e...cl \n c:lur;~ ccnsWu..c.~on of' ~\s pn:,je.L\-~ Any known drainage or flooding problems in areas near subject property? ____1_ No __ Yes Identify: \""h\~ "P'OJ«.....\-do~s ~'l-.,~~Y'\ ~ \00 ''1...-.f'\oodp\-..\n ·• Based on location of study property in a watershed, is Type 1 Detention (flood control) needed? (see Table B-1 in Appendix B) __ Detention is required. ./ Need must be evaluated . __ Detention not required. What decision has been reached? By whom? diw ~\OWS, 'D"''--\cl ~ ~\\ '""-~\C.. \W'\ ~~ c...\o~ . el.\,,.c.·~\. CO'r\VC"'\~ . °" ~,-...,.._~ \~ "t_VC.'""<..d • .. If the need for How was determination made? Type 1 Detention· -'Prov.\~;~· "° c...r-~ 's Crcdc. · must be evaluated: -~o\-\o~ .f '°""" ~\c.'4\ ... ~o-tU ef -pY"ukVt. \O~d , . c . P~°'" ditw(..\e>p<d c.ol'\d.\""' 0 ~ ~ STORMWATER DESIGN GUIDELINES Effective February 2007 Page 7 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised Februarv 2009 SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 3 -Pro~ert~ Characteristics I Continued (Page 3.3) Hydrologic Attributes of Subject Property (or Phase) (continued) Does subject property straddle a Watershed or Basin divide? _L No --Yes If ye_s, describe splits below. In Part 4 describe desiqn concept for handlinq this. Watershed or Basin Larger acreage Lesser acreage N/A Above-Project Areas(Section 11 , Paragraph 83-a) Does Project Area (project or phase) receive runoff from upland areas? ~No Yes -- Size( s) of area( s) in acres : 1) 2) 3) 4) Flow Characteristics (each instance) (overland sheet, shallow concentrated, recognizable concentrated section(s), small creek (non-regulatory), regu latory Watercourse or tributary); Flow determ ination: Outline hydrologic methods and assumptions: Does storm runoff drain from public easements or ROW onto or across subject property? --No --Yes If yes , describe facilities in easement or ROW: ' . . . ' .. . Are changes jn runoff characteristi cs 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 .I Yes Describe length and characteristics of each conveyance pathway(s). In clude ownership of property( ies ). RiJ"'o.f:f' .f,,.~ ~ sitt. · ~~-..~ c:k~" · ~~~io~. ,oo' ;.. Co.<tt<'~ Ur(.(.\(. y,A., ors ho.\\o w CJC"'<:.V\.1v....kd fk>...J. All f\ow wi\\ cross +'he. s~ Owr'\~ ·~ , ~6¥"" C..S E.,...c. -:ro"c..s, nc.1'3n~or4.~, -\y-..c.+ ~"°~ d \~Oo)I'"~' <"\~ in~ Co¥w-'~ Cxc.t..\c.... STORIVIWATER DESIGN GUIDELINES Effective February 2007 Page 8 of 26 APPENDIX. D: TECH. DESIGN SUIVllvlARY As Revised February 2009 .. I · SECTf ON IX APPE ND!X D -TECHN ICAL DES IGN SUMMARY Part 3 -Property Characteristics I Continued (Page 3.4) Hydrologic Attributes of Subject Property (or Phase) (contin ued) Conveyance Pathways (continued) Do drainage easements exist for any part of . pathway( s )? If yes, for what part of length? % Created by? __ plat, or __ instrument. If instrument(s), describe their provisions. __!!!___No · Yes Pathway Areas Nearby Where runoff must cross lower properties , describe characteristics of abutting lower property(ies). (Existin g watercourses? Easement or Consent aquired?) Cu.-.-U\.~\"\ """~ C:X-O'S,Se_~ -\-~~ r.c.\5\.\bor\~ oTY'~ Oll.lll"\C.d b\ WV\<. C,Nr.r\~ Eric. :S-o~~ . 'T\"\\-. w-.c...\-tS MA.ck. vp ~ ~<;.\urt.. \Q.r\cl w~~ \~~ s.\opc. 'Th.t.. IV\A.jo..-i~ of """c.. ~1v<L ~ h,,.,4£ no ~c...S . Describe any built or improved drainage facilities existing near the property (culverts, bridges, lined channels, buried conduit, swales, detention ponds, etc). N/A Drainage ~~~-c-~~~~~~~~~~~~~~~~~~~~~~~~~~~ Facilities Do any of these have hydrologic or hydraulic influence on proposed stormwater design? . No · __ Yes . If yes , explain: . , . tJ/A . STORMWATER DESIGN GUIDELINES Effective February 2007 Page 9 of 26 APPENDIX. D TECH. DESIGN SUMMARY As Revised February 2009 ·- SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce~t and Design Parameters I Start (Page 4.1) Stormwater Management Concept Discharge(s) From Upland Area(s) If runoff is to be received from upland areas, what design dra inage 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. ~4'o~Ld· s;tt... w~\\ be.. S'"-.kd Sv..c.n ~-\- .\M_ S;"" "-''\\ \'"C.C.C.WC.. Y\.\,W'\ ~ "'pstrc.uv"\ ~ ; " ~ SCJN'.C. ~~· F\ow wt\\~ be.. ~\(.. +o (""""' o.Ll"041 '\ ~ h""'L~ ~n.(.. ro~ ~ CM'\d o\o"""4..-d. ~ ~~vL. l~ · ~ ~~l 1.d ~ ~ Q~ ls ~~~ on .._ h~s~~o\n-\ an \\...c.. ~ o..111\~ 5.,.. c:-.1twarcl ~ ~ ~C...'S. j\"\ ~ t'\Of"~.\ 1 ,So~.\-f ... ~d So~~'i+ dA\'"~01\, /Jo ~~ (:lc,.va...\op~-\" ~ up~ o..~u-1\ CL.rt. proj<.c...\e.d. Discharge(s) To Lower Property(ies) (Section II , P~ragraph E1) Does project include ·drainage features (existing or fu.ture) proposed to become pu'blic via platting? ~No __ Yes Separate Instrument? v' 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# ) Scenario 2: Provide general description of how release(s) will be managed to pre-development conditions (detention, sheet flow, partially concentrated, etc.). (Attached Exhibit# ) BUAV5C. +~ Si.\<. i'& prolos<.d -to be. o. \nnc..~~nc.. roc.\c. pa..d ~ ~ <.it\<s+\~ pC>l"\d '""P'-'V'°u~ C.0-4<) ;s be-\~ {:i\\c,d ii\, ~ 1:>0'"° c:k..vc..\ippe.cl .f\eow~ o.rt.. on\"\ s\i5'°'.\\"\ Ms · · ~ t\-\t. 'P'"C. ck.~~\opect c.on~~ ons. ~6.1.1~ ~ ~s ~ ~ c.\osc. p<"QK'""~~ -4o Co.r"-c.r's C<~, we.. ~o~cose d\YU..\-c.o .... v~. . ?rt. c:l.&NuOpc...l ~ po-s+ c:lc.ve.\o p~ ciYM~~ o.rt.c.. l'W'\~S '"'cl c..l~,. 4¥1... ~. Combination: If combination is proposed, explain how discharge will differ from pre- development conditions at the property li ne 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 _L_ Yes Explain and provide documentation. ~ CWt\eJr ~ "°~' . . ,._ ~ c:lw<.\o~ ~ t"C.~\'Y\~~ pn>~ ~~ ?""Ope..<~. STORMWATER DESIGN GUIDELINES Effective February 2007 Page 10 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 , . l SECTION lX APPEND[X D -TECHt\!!CAL DESIGN SUMMARY Part 4 -Drainage Conce~t and Design Parameters / Continued (Page 4.2) Stormwater Management Concept (continued) Within Project Area Of Multi-Phase Project ;J f A Identify gaining Basins or Watersheds and acres sh ifting: Will project result in shifting runoff between Basins or between What design and mitigation is used to compensate for increased runoff Watersheds? from gaining bas in or watershed? No -- Yes -- How will runoff from Proj ect 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 Proiect Area (type & location of facilities): (Attached Exhibit # ) 3. By phase (or site ) project: Describe planned mitigation measures for phases (or sites) in subsequent questions of thi s Part. Are aquatic echosystems proposed? __ No --Yes In which phase(s) or project(s)? 0-· "D OJ en c OJ c >-Are other Best Management Practices for reducing siormwater pollutants proposed? ro 0... No Yes Summarize type of BIV1P and extent of use: en ---- c .Ql en OJ 0 0 z ro I If design of an y runoff-handling fac ilities deviate from provisions of B-CS Technical u OJ Specifications , check type facility(ies) and explain in later questions. 0.. (J) Detention elements Conduit elements Channel features ~ ------ <t: / __ Swales Ditches Inlets __ Valley gutters __ Outfalls ---- J --Culvert features __ Bridges Other STOR!v1WATER Dc SIGN GUIDELll\JES Effective Febru ary 2007 Page 11 of 26 APPEf\!DIX. D TECH. DESIGl\J SUlv1 1v1A RY As Revisec Februarv 2009 ' I I ' I I I SECTION rX . ' APPENDIX D -TECHNICAL DESIGN SU MMARY Part 4 -Drainage Conce12t and Design Parameters I Continued (Page 4.3) Stormwater Management Concept (continued} Within Project Area Of Multi-Phase Project (continued) ~J /A Will Project Area include bridge(s) or culvert(s)? __ No __ Yes Identify type and general size and In which phase(s). If detention/retention serves (will serve) overall Project Area, describe how it relates to subject phase or site project (physical location, conveyance pathway(s), construction sequence): Within Or Serving Subject Property (Phase, or Site) If property part of larger Project Area, is design in substantial conformance with earlier analysis and report for larger area? --Yes No, then summarize the difference(s): N/4 Identify whether each of the types of drainage features listed below are included, extent of use, and general characteristics. Typical shape? I Surfaces? C'-· ""O Q) (/) Steepest side slopes: Usual front slopes: Usual back slopes: (/) ::i OJ (/) >- Q) I ..r::: Flow line slopes : least Typica l distance from travelway: .8 ""O (Attached Exh ibit # ) Q) 0 typical greatest ""O (/) z ""O ~1 cu 0 Are long itudinal 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? ..D Q) No Yes If yes explain: :s ('-· >---u ""O I ..r::: OJ ~ ([) ·-::i 5 '-Are va lley gutters proposed to cross any street away from an intersection? ([) Q) QJ =§ 0 No Yes Explain (number of locations?) ~~zl ---- ~ ~'- STORlv1VVATER DESIGN GU IDELll'-JES Effective February 2007 Page 12 of 26 APPENDIX. D: TECH. DESIGN SU1v1MARY As Revised Februarv 2009 I , . I SECTfON ·!X' APPENDIX D -TECHNICAL DES lGN SU MM ARY Part 4 -Drainage Concept and Design Pa rameters I Continued (Page 4.4) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) ..... ~ :::; OJ -v~ c 'D ro (J) .D ;:i ~ ·= :::; - l) § ..r::. l) ·~~ (/) Ci) (J) ..'.::; (/) (J) .... <( C"'· Gutter line slopes: Least ____ _ Usual Greatest Are inlets recessed on arterial an d collector streets? __ Yes identify where and why. __ No If "no'', Will inlets capture 10-year design stormflow to prevent flooding of intersections (arterial with arterial or col lector)? __ Yes __ No If no, explain where and wh y 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. Sao 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 Expla in "no" answers . ! Wil l 100-yr stormfl ow be contained in combination of ROW and buried conduit on / whol e length of all streets? __ Yes __ No If no, describe where and why. j I Do designs for curb, gutter, and inl ets comply wi th B-CS Technical Specifications? ___ Yes __ No If not, describe difference(s) and attach justification. I 1 Are any 12-inch laterals used? used. !\Jo Yes Identify length(s) and where I ~ (/) Pipe runs between system I Typical ::. ~ access points (feet): -----Longest ____ _ ~ / i Are. junction boxes used at each bend? Yes No If not, explai n where » an o why. (/) c ro o -D zl E ") ~ I Are downstream soffits at or below upstream soffits? .:!! / Yes __ No __ If not, explain where and why: / Least amount that hydraulic I grade line is below gutter line (system-wide): STOR l1~\f\IATER DESIGl\J GUIDELl/\IES Effective February 2007 Page 13 of 26 APPEl\JDIX. D TECH. DESIGN SUMMARY As Revised F ebruarv 2009 SECTiON IX . . APPEND IX D -TECH NI CAL DES IGN SUMMARY Part 4 - Drainage Conce~t and Design Parameters / Continued (Page 4.5 ) Stormwater Management Concept (contin ued) Within Or Serving Subject Property (Phase, or Site) (contin ued ) ~ Describe watercourse(s), or system(s ) receiving system discharge(s) below en (include design discharge velocity, and angle between converging flow lines). Q) (.) c 1) Watercourse (or system ), velocity, and angle? ro u; c ~ ~o al E 2) Watercourse (or system), velocity, and angle? ::; ,__ c 0 ·--c . 0 .s .S -~ != Q) en - E -3) Watercourse (or system), velocity, and angle? 2 ro ro ~en ~ en a> :::; c :Q 0 ·-> ~ e "O Cl. E-,__ Q) For each outfall above, what measures are taken to prevent erosion or scour of 0 Q) -.r:. Cf) en receiving and al l facilities at juncture? 2 1) ro ,__ ro Cl. 2) Q) en c 3) 0 - Are swale(s) situated along property lines between properties? --No --Yes Number of instances: For each instance answer the following questions. Surface treatments (including low-flow flumes if any): C'-· en (i) ~en -Q) Flow line slopes (minimum and maximum): en >-c I ~ "O .8 ~ 0 en Z Outfall characteristics for each (velocity, convergent angle, & end treatment). ::; j~/ en Q) ,__ Will 100-year design storm runoff be contained within easement(s) or platted drainage <( ROW in al l instances? --Yes --No If "no" explain: STORIV1WATER DESIGN GUIDELINES Effective February 2007 Page 14 of 26 APPENDIX. D: TECH . DESIGN SUIV11V1ARY As Revised Februaa1 2009 .>. ·SECTION IX APPEl-.ID!X D -TECHNI CAL DESIGN SUMMARY Part 4 -Drainage Conce12t and Design Parameters / Continued (Page 4.6) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Are roadside ditches used? No Yes If so , pro vide the following : Cf) -- Q) Is 25-year flow contained with 6 inches of freeboard throughout? __ Yes --No _c ~ Are top of banks separated from road shoulders 2 feet or more? __ Yes --!\lo 0 Are all ditch sections trapezoidal and at least 1.5 feet deep? Yes No Q) ---- "D For any "no" answers provide location( s) and explain: Cf) "D cu 0 er: If condu it is beneath a swale, provide the following information (each instance). Instance 1 Describe general location, approximate length: Cf) Q) Is 100-ye ar design flow contained in conduit/swale combination? Yes No >----- lw If "no" explain: c Space for 100-year storm flow? ROW Easement Width 0 cu z u:; Swale Surface type, minimum Conduit Type and size, minimum and maximum ')/ ~ and maximum slopes: slopes, design storm: 0 C'-· "D Cf) "D Inlets Describe how conduit is loaded (from streets/storm drains , inlets by type): Q) cu c >-c cu c _c cu () ...... c .2 Q) c Access Describe how maintenance access is provided (to swal e, into conduit): 0.. 2 0 ....... cu 0 E :::J ...... Q) .2 -c c ·-Instance 2 Describe general location, approximate length: Q) "D E Q) cu Cf) ::;; Cf) Cf) Q) c J2 Is 100-year design flow contained in conduit/swale combination? --Yes --No 0 > If "no" explain: 0 cu ...... c 0.. .D Q) E Q) Space for 100-year storm flow? ROW Easement Width 0 _c () Cf) Swale Surface type, minimum Conduit Type and size, minimum and maximum ·-2 and max imum slopes slopes. design storm : :::J cu "D ...... c cu 0 0.. () Q) Inlets Describe how conduit is loaded (from streets/storm drains , inlets by type): ]! Cf) c cu 0 5 Cf) I ~ Access Des cribe how maintenance access iE provided (lo swale, into conduit) <( I STORlv1\f\/ATER DESIGN GUIDELll\JES Effective February 2007 Page 15 of 26 APPcl\JDIX. D TECH. DESIGl\J SUMMARY As Revised Februarv 2009 I I I SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 - Drainage Gonce Qt 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: c CIJ E Q_ x 0 w ...... ..__ ~ CJ) Is 100-year design flow contained in swale? Yes No Is swale wholly 0 Q) ----c >-within drainage ROW? Yes No Explain "no" answers: ::i I ----...... Q) > Q) Access Describe how maintenance access is provide: (.) Q) ...... 0 ~ z :::i i ~1 Instance 2 Describe general location, approximate length, surfacing: Q) ·c <:'-· :::i 2 .0 c ~ Q) :::i E 0 ::5 Q) CJ) Is 100-year design flow contained in swa le? Yes No Is swale wholly 5 CIJ ----Q) within drainage ROW? __ Yes No Explain "no" answers: CJ) ...... ~ 0 -- CIJ s 5 CJ) 0 = 0::: Access Describe how mai ntenance access is provided: ~ .S2 .0 ::i Q_ Instance 3. 4. etc. If swales are used in more than two instances, attach sheet providing all above information for each instance. "New" channels: Wil l any area(s) of concentrated flow be channelized (deepened, widened , or straightened) or otherwise altered? --r\Jo --Yes If only slightly shaped, see "Swales" in this Part. If creating side banks, provide information below. <:'-· -0 c Will design replicate natural channel? Yes No If "no", for each instance Q) ----CJ) ~ describe section shape & area, flow line slope (min. & max.), surfaces, and 100-year 0 Q_ Q_ x design flow, and amount of freeboard: 2 w Q_ Instance 1: 2 CJ) (j) c >-Q) E I Q) > Instance 2 0 ...... Q_ E 0 z (ij ~1 c Instance 3: c CIJ ..c u STORIVl\IV ATER DESIGN GUIDELINES Effective February 2007 Page 16 of 26 APPENDIX. D: TECH. DESIGN SUl\/11\/IARY As Revised Februarv 2009 I I ' ~ ... J SECTfON IX APPEND!X D -TECHl'>!ICAL DESIGN SUMMARY Part 4 -Drainage Con ce2t and Design Parameters / Continued (Page 4.8) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) iJ Ir:.. Existing channels (small creeks): Are these used? --No --Yes If "yes" provide the information below. Will small creeks and their floodplains remain und isturbed? __ 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.), suriaces, an d 1 DO-year design flow. -"D (!) ::i c :.;:::; / Watercou rses (and tributaries): Aside from fringe changes, are Regulatory c 0 u Watercourses proposed to be altered? __ l\Jo Yes Explai n below. -- 2 Submit full report describing proposed changes to Regulatory Watercourses. Address c (!) existing and proposed section size an d shape, surfaces, alignment, flow line changes, E (!) length affected. and capacity, and provide full documentation of analysis procedures > 0 and data. Is full repori submitted? Yes No If '·no·· expl ain: '-Cl. -- E - Qi c c cu All ProQosed Channel Work: For all proposed channel work, provide information ..c u 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 1 DO-year flow be contained with one foot of freeboard? --Yes --No If I not. identify location an d explain I I l Are ROW I easem ents sized to conta in channel and required maintenance space? --Yes --No 11 not. identify location(s) and explain l STORIVlWATER DESIGl\i GUIDELll\IES Effective February 2007 Page 17 of 26 APPE"JDIX. D: TECH. DESIGI SUIVllVIARY As Revised Februarv 2009 I I I I I SECTfO N rx APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce!2t and Design Parameters / Continued (Page 4. 9) Stormwater Management Concept (continued) Within Or Serving Subject Pro perty (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 (1 0 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: (/) (j) r I For each facil ity what is 25-yr design Q, an d design of ou tlet structure? Facility 1: 0 z Facility 2: ~1 Do outlets and spillways discharge into a public facility in easement or ROW? Facility 1: __ Yes No Facility 2: Yes No ------C'-· If "no" explain: "O (j) (/) 0 a. 0 ._ CL For each, what is velocity of 25-yr design discharge at outlet? & at spi llway? (/) (j) Facility 1: & Facility 2: & :;::; 'l) Are energy dissipation measures used? No Yes Describe type and cu ---- LL location: c 0 -c 2 (j) 0 (j) For each, is spillway surface treatmen other than concrete? Yes or no, and describe: ._ <( F acilit~r 1: Facility 2: For each, wha t 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 · I Facility 2 STORlvlWATER DESIGN GU IDELINES Effective February 2007 Page 18 of 26 APPENDIX. D: TECH. DESIGN SUIVJlv1ARY As Revised February 2009 . " 1 SECTION iX APPENDIX D -TECHN ICAL DESIGN SUMMARY Part 4 -Drainage ConceQt and Design Parameters / Continued (Page 4.10) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Do structures comply with B-CS Specifications? Yes or no , and explain if "no": Facility 1; (f) <l) :;::; := :0 ~ <l) Facility 2: LL :::; c c:.;::::; 0 c :;::; 0 c (.) w~ Q) For additional facil ities 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 al l cases? ---Yes .../ No -- Without causing flowing or standing water on public roadway? Yes ./ No ---- Designs & materials comply with B-CS Technical Specifications? __ Yes .I No -- Explain any "no" answers: C'-· (f) rn c (f) Are culverts parallel to public roadway al ignment? Yes ./ (f) No Explain: 0 ---,__ (f) (.) <l) 2 >-!~1 Creeks at Private Drives: Do private driveways, drives, or streets cross drainage cu ways that serve Above-Project areas or are in public easements/ ROW? "O 0 No ./ Yes If "yes" provide information below. <l) z ----(f) I :::; How many instances? ' Describe location and provide information below. ~ t).,-\..,C.W""'f e.,~~ +o Sw~ S~O" .Wj~ <l) Location 1: 2'. ~ ?'fO~~ ~· :::; (.) <l) Location 2: ,__ <( Location 3: For each location enter value for: 1 2 3 Design year passing without toping travelway? i OO Water depth on travelway at 25-year flow? D Water depth on travelway at 100-ye ar flow? D For more instances describe location and sam e information on separate sheet. STORMWATER DESIGN GUIDELINES Effective February 2007 Page 19 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised Februarv 2009 SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage ConceQt and Design Parameters J 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 __ Yes, then provide full report documenting assumptions, criteria, analysis, computer programs, and study findings that support proposed design(s). Is report provided? __ Yes --No If "no", explain: -Arterial or Major Collector Streets: Will culverts serve these types of roadways? a:; a.> No Yes How many instances? For each identify the .r::. (/) ---- 2 location and provide the information below. (/) cu Instance 1: a.> ...._ >-g_ I~ Instance 2: Instance 3: c 0 o~ Yes or No for the 100-year design flow: 1 2 3 z~ Headwater WSE 1 foot bel ow lowest curb top? '>I~ Spread of headwater within ROW or easement? E C'-· cu Is velocity limited per conditions (Table C-11)? (/) (/) g'-o Explain any "no" answer(s): ·-c ~ cu 0 c ...._ 0 (.):.;::; >-cu cu (.) ~ .9. . -0 a.> cu .D Minor Collector or Local Streets: Will culverts serve these types of streets? 0 ·-...._ ...._ (.) (.) No Yes How many instances? for each identify the ·-(/) -a.> ----..g -0 location and provide the information below: Q_ a.> ..... Q_ Instance 1: cu i:':' -0 >-Instance 2: a.> c ~ cu (/) 0 Instance 3: ~ (f),, > a.> For each instance enter value, or "yes" I '!n0 " for: '1 2 3 -(.) ::i c (.) cu Design yr. headwater WSE 1 ft. below curb top? (!) en ...._ c <{ ·-100-yr. max. depth at street crown 2 feet or less? a.> ...._ 0 Product of velocity (fps) & depth at crown (ft)=? E '-.£2 Is velocity limited per conditions (Table C-11 )? Limit of down stream analysis (feet)? Explain any "no" answers : STORMWATER DES IGN GUIDELINES Effective February 2007 Page 20 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 SECTrON !X APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce~t and Design Parameters / Continued (Page 4.12) Stormwater Management Concept (continued) Within Or Serving Subject Property {Phase, or Site) (continued) t.J/A All Proposed Culverts: For all proposed culvert facilities (except driveway/roadside ditch intersects) provide information requested in next eight boxes. Do culverts and travelways intersect at 90 degrees? --Yes --No If not, identify Jocation(s) and intersect angle(s), and justify the design(s): Does dra inage way alignment change within or near limits of culvert and surfaced approaches thereto? __ No --Yes If "yes" identify location(s), describe change(s), and justification: Are flumes or conduit to discharge into culvert barrel(s)? __ No --Yes If yes, identify location(s) and provide justification: -Are flumes or conduit to discharge into or near surfaced approaches to culvert ends? "O No Yes If •·yes' identify location(s), describe outfall design treatment(s): QJ ----:::; c c 0 (.) 2 I-QJ 2: Is scour/erosion protection provided to ensure long term stability of culvert structural :::; u components, and surfacing at culvert ends? --Yes --No If "no" Identify locations and provide justification(s): Will 100-yr flow and spread of backwater be fully contained in street ROW, and/or drainage easements/ ROW? __ Yes --!\Jo if not, why not? Do appreciable hydraulic effects of any culvert extend downstream or upstream to neighboring land( s) not encompassed in subject property? --!\Jo --Yes If ··yes·· describe location(s) and mitigation measures: I I I Are all culvert designs and materials in compliance with 8-CS Tech. Specifications? __ Yes __ No If not. explain in Special Design Section of this Part. STORlv1\f\/ATER DESIGN GUIDELINES Effective February 2007 Pags 21 of 26 APPENDIX. D TECH. DESIGI\! SUMMARY As Revised Februarv 2009 I I I I I SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce~t 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? _L No --Yes If "yes" provide the following information. Name(s) and functional classification of the roadway(s)? What drainage way(s) is to be crossed? -(/) Q) Ol "O ·;:::: r:n A full report supporting all aspects of the proposed bridge(s) (structural , geotechnica/, hydrologic, and hydraulic factors) must accompany this summary report. Is the report provided? --Yes --No If "no" explain: Is a Stormwater Provide a general description of planned techniques: £ Pollution Prevention S• \~ ~CX\C.C. I ~~"''O" e-~.w....-.~ ... I Stl.: .\-m Pla n (SW3P) ::J a established for '-project construction? OJ -ro s No --__.:!_Yes Special Designs -Non-Traditional Methods Are any non-traditional methods (aquatic echosystems, wetland-type detention, natural stream repl ication, 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? N /Pt STORIV1\/VATER DESIGN GUIDELINES Effective February 2007 Yes ---- Page 22 of 26 No If "no" exp lain: APPENDIX. D: TECH. DESIGN SUIV11V1ARY As Revised Februarv 2009 I SECTION IX APPENDfX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce~t and Design Parameters J 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 Al/l's If any design(s) or material(s) of traditional runoff-handling facilities deviate from provisions of B-CS Technical Specifications, check type facility(ies) and explain by specific detail element. Detention elements __ Drain system elements Channel features ---- Culvert features Swales Ditches Inlets Outfalls ---------- __ Valley gutters __ Bridges (explain in bridge report) In table below briefly identify specific element, justification for deviation(s ). Specific Detail Element Justification for Deviation (attach additi onal sheets if needed) 1) 2) 3) I ' ' 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? ./ Yes No ---- Briefly summarize the range of applications made of the Rational Formula: (J..\e""\~ ~c.. A.'t\d (>C~+ oleNc..\o~t.d pc.A.~ ~\ow.S \JS;~ ~Y-~) c:kc;.Uf ~~ '"' O:ft" ~~c.k\\V\C.S /41\6 i:A»\c."> •'f\ Ap~I-c. ~ ~~ ~. 4"' ~'°~ "~ a»~c.tet\!\ p(' o.Lf is ~ ~' ~ ~oc..X.. ~ b1..->td 01'"\ <s~\..r ~~\is\...&..d .v,..\.u:..~ -Vor \-'h.~s ~f>C.. ~~ s~""fu.e... What is the size and location of largest Design Drainage Area to which the Rational Formula has been applied ? {.';\ acres STORIVlWATER DESIGN GUIDELll\JES Effective February 2007 Location (or identifier): t>p::i.. \ lP~\-·~ '\>""c.) Page 23 of 26 APPENDIX. D: TECH. DESIGN SUfVllVlARY As Revised February 2009 SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce1:2t and Design Parameters j Continued (Page 4.15) Design Parameters (continued) Hydrology (continued) In making det~rn;iinations for time of concentration, was segment analysis used? __ No ./ Yes In approximately what percent of Design Drainage Areas? lOO % As to intensity-duration-frequency and rain depth criteria for determining runoff flows, were any criteria other than those provided in these Guidelines used? ~ No --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 /J/A ~IA Storm drain system for local streets NIA NIA Open channels NIA NIA Swale/buried conduit combination in lieu of channel l'J/p, NIA Swales IOC -z..~ Roadside ditches and culverts serving them l'JIA NIA Detention facilities : spillway crest and its outfall NIA NIA Detention facilities: outlet and conveyance structure(s) JJ/A "''"" Detention facilities: volume when outlet plugged NIA IJ/A Culverts serving private drives or streets /DO '" Culverts serving public roadways /\J/A IJ/A Bridges: provide in bridge report. /\l}A JJIA- Hydraulics What is the range of design flow velocities as outlined below? Design flow velocities; Gutters Conduit Culverts Swales Channels Highest (feet per second) ---s .C1" i.oc.. -. . ~ 1.oo.l .. Lowest (feet. p~r.~econd ). ---z., oc. ~ -,, Streets and Storm Drain Systems Provide the summary information outlined below: Roughness coefficients used: For conduit type(s) .- STORMWATER DESIGN GUIDELINES Effective February 2007 For.street gutters: - Page 24 of 26 - Coefficients: ..... r APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 ', SECTI ON IX APPENDIX D -TECHNI CAL DES IGN SU MMARY Part 4 -Drainage ConceQt and Design Parameters I Continued (Page 4.16) Desig n Parameters (continued) Hydraulics (continued) Street and Storm Drain Systems (continued) For the following, are assumptions other than allowable per Gu idelines? Inlet coefficients? No Yes Head and friction losses No Yes -------- Explain any "yes" answer: /\J/A In conduit is velocity generall y increased in the downstream direction? --Yes --No Are elevation drops provided at inlets, manholes, and junction boxes? --Yes --No Explain any "no" answers: NIA Are hydraulic grade lines calculated and shown for design storm? --Yes --No For 100-year fl ow conditions? --Yes --No Explain any "no" answers: A) /Pt What tailwater cond itions were assumed at outfall po int(s) of the storm drain system? Identify each location an d explain: Al /A ' '• ' ' ' . -. r -. . ' Open Channels If a HEC analysis is utilized, does it follow Sec Vl .F.5.a? · Yes· · No ---- Outside of straight sections, is flow regime within limits of sub-critical flo.l.'\1.? __ Yes __ · No If "no" list locations and explain: . ' IV /A Cu lverts If plan sheets do not provide the following for each culvert, describe it here. For each design discharge, wi ll operation be outlet (barrel) control or inlet control? IY'\\L~ c..o C'\!w"C> \ Entrance, friction and exit losses: t , -" ' ,. .Bridges Provide all .iri bridge report N If>\ STORlv1WATER DESIGN GUIDELINES Effective February 2007 Page 25 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised Februarv 2009 SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce12t and Design Parameters I 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 ,r • .. Part 5 -Plans and SQecifications Requirements for subm ittal of construction drawings and specifications do not differ due to use of a Technical Design Summary Report. See Section Ill, Paragraph C3. Part 6 -Conclusions and Attestation Conclusions Add any concluding information here: ~ l • cu.c.u.-Tl...J t. S""W\~""\ No ~(.Jr'i.(.. \W\ ~~ ~~.\-$~ C...Un~ S£.~vo.k c..ow.<) Fa't\Pi ~\llJt>cl ~ Loa....tn C> o('\ VV"1> ~~,"~ An..-Mo..p~ F\ow C.,..\<,.u..\1..\-\o"'~ CCI \vtN' tr I Swo.\e. CA,\ c,.&.A.\Wn~~ =' ''" Attestation Provide attestation to the accuracy and completeness of the foregoing 6 Parts of this Technical Desiqn Summary Drainaqe Report by siqninq and sealinq below. "This report (plan) for the drainage design of the development named in Part a ·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 improvements have been issued or fall under applicable general permits." ---'""'''''' L1!:1£~gineer --~~OF i~\\ State of Texas PE No. J ()';; I '-/ °l STORMWATER DESIGN GUIDELINES Effective February 2007 Page 26 of 26 (Affix Seal) ;~'r' ········ '• ;c.,/*"•.,d" •• J'*:' ··.* ,,, "'*: "·*~ , ..••............••..•••.•.•.• ~ ~ MARK A. SAVARINO J ~·····························~ ~, ~ ... 105149 ... ~ J 4t4 ~~~ICENS~?.··.· ~,; ia.. ••• .. .... ,..;s -., ~~'t -~~: APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 EXHIBIT B FEMA FLOOD MAP