Loading...
Drainage Report Drainage Report for The Barracks II Subdivision Phases 107 College Station, Texas October 2014 Owner/Developer: Heath Phillips Investments, LLC 3302 General Parkway College Station, TX 77845 Prepared By: Schultz Engineering, LLC TBPE Firm No. 12327 P.O. Box 11995 College Station, TX 77842 2730 Longmire Drive, Suite A College Station, Texas 77845 (979) 764-3900 I . • Drainage Report—Executive Summary . The Barracks II Subdivision, Phases 107 . College Station,Texas S ENGINEER • SCHULTZ ENGINEERING,LLC. P.O.Box 11995 College Station,Texas 77842 Phone: (979)764-3900 Fax:(979)764-3910 OWNER/DEVELOPER Heath Phillips Investments,LLC 3302 General Parkway College Station,TX 77845 Phone: (979)690-5000 GENERAL DESCRIPTION AND LOCATION I . This project consists of the development of Phase 107 of the Barracks II Subdivision in College Station. Phase 107 is a townhouse residential development,which will include the construction of utility and roadway infrastructure. w I ill Location: Phase 107 is located northeast of Phase 106 and northwest of Phase 108 of the Barracks II Development. The Barracks II Subdivision is a 108-acre + "* development located midway between Rock Prairie Road and Cain Road in 3 . south College Station. It is bounded on the west by Holleman Drive South and on the east by Old Wellborn Road. - Description: • Area: 7.654 Acres ® ■ Proposed Land Use: Townhouse Residential + rti.r • #of Lots: 63 lots ■ Existing Land Use: Vacant I • • Land Description: The terrain slopes generally towards the north. Primary Drainage Facility: Tributary B.3 of Bee Creek Flood Hazard Information: FEMA FIRM: #48041C0305F,Dated April 2,2014 Floodplain: None of this phase of the development lies within the floodplain. HYDROLOGIC CHARACTERISTICS The existing site is cleared. The elevations range from 303 to 299,sloping generally in a northerly direction. The majority of the runoff will be directed to the roadways and the proposed storm sewer system and will discharge into Old Wellborn Road roadside ditch. The stormwater detention facility drainage report prepared by Kimley-Hom has been revised to evaluate the proposed drainage of the site and to address the increase in peak flow resulting from this development.The remaining runoff will be directed to the roadways and the proposed storm sewer system and will discharge into the existing detention facilities on Lot 1,Block 28 Phase 300 of The Barracks II Subdivision. Ultimately,this runoff flows into Tributary B.3 of Bee Creek. GENERAL STORMWATER PLAN The drainage plan for this development will involve the installation of storm sewer pipes and inlets,which will collect and convey a portion of the runoff into the existing storm sewer system and then to the existing detention pond. This development will also discharge into the existing drainage ditch along Old Wellborn Road which will C p collect and convey the runoff downstream. The runoff that is collected by the existing detention ponds and the Old Wellbom Road ditch will be discharged into tributary B.3 of Bee Creek. • The detention pond analysis and design for this phase is covered under the drainage report titled,"The Barracks Detention Facility Design City of College Station,Texas,Dated July 2012"prepared by Kimley-Hom and as modified in September 2013 and as revised in the report submitted in September 2014.This revised report will take into account the development of the adjacent tract to the north which has been acquired and will become part of the Barracks. ! o COORDINATION&STORMWATER PERMITTING This project has a Notice of Intent filed with the Texas Commission for Environmental Quality. No other permits are anticipated for this project. DRAINAGE DESIGN General Information: Stormwater runoff from Phase 107 of the subdivision will be collected by a storm sewer system. The location of the drainage areas for evaluation of the gutter.depth check,inlet sizing,pipe evaluation and channel sizing are shown on two Exhibit A & B. Refer to Exhibit B for the locations of the inlets and storm I • sewer pipes. Street Design: Kimber Lane: . Standard Cross-Section(3%cross-slope,27' B-B Residential Roadway) Lay down and standard curb and gutter on residential streets Deacon Drive: Collector Street Cross-Section(3%cross-slope,48' B-B) +e Standard Curb and gutter Concrete Pavement Standard recessed curb inlets(5' &10'in length) lei® T',Methodology: TR 55 ® Tc Minimum: 10 Minutes law Design Storm Event: 10 year design storm& 100 year analysis for residential and collector streets& • storm sewer • Pipe Materials: Class III RCP,Profile Gasket in accordance with ASTM C443,ASTM C76 and Corrugated HDPE Storm Sewer Pipe with smooth interior Mannings n Values: 0.013 for pipes 0.018 for Streets Runoff Coefficients: 0.75 for developed lotstot . 0.45 for undeveloped land I Design Constraints: depth Max. water d th in gutter: 4.5" or 0.375' for the 10 year design storm for residential and collector streets Min.pipe flow velocity:2.5 fps Max.pipe flow velocity: 15 fps 100-yr storm runoff maintained within the ROW(3"above curb) • . 25%reduction of cross-sectional area of pipes less than 24"in diameter Min. 1' freeboard for the 10 year design storm depth of flow • Design Software: Excel Spreadsheets,Hydraflow Express Extension for AutoCAD Civil 3D 2013, &Autodesk Civil 3D Storm Sewer Analysis. 4111 • The software was used to compute pipe capacities, flow rates and velocities, compute hydraulic grade line elevations, headwater elevations, gutter depth & inlet sizing. 111 The requirement for a 25% reduction in cross sectional area of pipes 24" in - diameter or less is achieved by using internal pipe diameters that are less than the standard diameter. The 24"diameter pipe areas were reduced by 25%and a a.r 20.6" diameter pipe was used in the analysis and the 18" diameter pipe areas • were reduced by 25%and a 15.6"diameter pipe was used in the analysis. Design Results: The data presented in the Appendices indicates the gutter depth, inlet sizing, ® pipe sizes and channel sizing is in accordance with the requirements of and the • City of College Station. Detention Analysis: Runoff from the Barracks II Subdivision was previously studied and detention ponds were designed for the entire development including this phase. See the drainage report titled, "The Barracks Detention Facility Design City of College oink Station, Texas, Dated July 2012" and as modified in September 2013 and by a revised design being prepared by Kimley-Horn submitted in September 2014. Sheet 05, "Proposed Condition Drainage Area Map", from the Kimley-Horn September 2014 "Modifications to The Barracks Detention Facility" design shows Drainage Area Cl, 18.56 acres of the project area discharging into the Old Wellborn Road right of way. With the final design of Phase 107 and 108 the computed area discharging into the Old Wellborn Road right of way is 18.56 • acres. Since this matches the area shown by Kimley-Horn the existing detention facilities for The Barracks are adequate for this phase of the subdivision and no additional pond construction or modifications are necessary. • Applicable Exhibits: Exhibit A—Drainage Area Map ID Exhibit B—Drainage Plan Appendix Al—Drainage Area Summary Appendix Bl—Depth of Flow in Gutter L Appendix B2—Storm Sewer Inlet Summary Appendix C1—Storm Sewer Pipe Summary Appendix D—Technical Design Summary c CONCLUSION The storm sewer,inlets&channel drainage system for Phase 107 of the Barracks II Subdivision will function within the requirements and restrictions of the BCS Design Guidelines. The existing detention facilities are adequate for this phase of the subdivision and no additional pond construction or modifications are necessary I CERTIFICATION • I,Joseph P. Schultz,Licensed Professional Engineer No. 65889,State of Texas,certify that this report for the • drainage design for The Barracks II,Phase 107,was prepared by me in accordance with the requirements 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. 111• r OF • Josept . Sct ultz,P.E. • .fir JOSEPH P. SCHULTZ • an. 65889; • ID Its40...NA • - ID �lS�l • F-12317 SCHULTZ ENGINEERING, U.0 • • • • • • • • • • • - • • • - • - • • • • C C C C C C C C C EXHIBIT A DRAINAGE AREA MAP EXHIBIT B DRAINAGE PLAN C C C C C C C C APPENDIX Al DRAINAGE AREA SUMMARY C C APPENDIX Al Barracks II Phases 107 Drainage Area Summary 10 year storm 100 year storm Area,A C tc Area# lie Qio 1100 Qin (acres) (min) (in/hr) (cfs) (in/hr) (cfs) 700 0.85 0.75 10.0 8.635 5.50 11.639 7.42 700A 0.49 0.75 10.0 8.635 3.17 11.639 4.28 700B 0.36 0.75 10.0 8.635 2.33 11.639 3.14 701 0.39 0.75 10.0 8.635 2.53 11.639 3.40 701A 0.28 0.75 10.0 8.635 1,81 11.639 2.44 701B 0.10 0.75 10.0 8.635 0.65 11.639 0.87 702 0.59 0.75 10.0 8.635 3.82 11.639 5.15 702A 0.35 0.75 10.0 8.635 2.27 11.639 3.06 702B 0.24 0.75 10.0 8.635 1.55 11.639 2.10 703 0.27 0.75 10.0 8.635 1.75 11.639 2.36 703A 0.11 0.75 10.0 8.635 0.71 11.639 0.96 SD 703B 0.17 0.75 10.0 8.635 1.10 11.639 1.48 704 0.85 0.75 10.0 8.635 5.50 11.639 7.42 IlD 704A 0.34 0.75 10.0 8.635 2.20 11.639 2.97 704B 0.51 0.75 10.0 8.635 3.30 11.639 4.45 0 705 0.41 0.75 10.0 8.635 2.66 11.639 3.58 0 706 1.00 0.65 10.0 8.635 5.61 11.639 7.57 0 707 1.35 0.75 10.0 8.635 8.74 11.639 11.78 1110 707A 0.94 0.75 10.0 8.635 6.09 11.639 8.21 707B 0.41 0.75 10.0 8.635 2.66 11.639 3.58 0 708 0.51 0.75 10.0 8.635 3.30 11.639 4.45 - 708A 0.27 0.75 10.0 8.635 1.75 11.639 2.36 708B 0.24 0.75 10.0 8.635 1.55 11.639 2.10 hill 709 1.31 0.75 10.0 8.635 8.48 11.639 11.44 li - 709A 0.87 0.75 10.0 8.635 5.63 11.639 7.59 ID 709B 0.44 0.75 10.0 8.635 2.85 11.639 3.84 III 710 0.54 0.75 10.0 8.635 3.50 11.639 4.71 711 0.40 0.75 10.0 8.635 2.59 11.639 3.49 € 712 0.26 0.75 10.0 8.635 1.68 11.639 2.27 Ili 713 0.16 0.75 10.0 8.635 1.04 11.639 1.40 III The Rational Method: Q=CIA I=b/(tc+d)e tc=L/(V*60) Q=Flow(cfs) tc=Time of concentration(min) L=Length(ft A=Area(acres) V=Velocity(ft/sec) C=Runoff Coeff. I=Rainfall Intensity(in/hr) • • • • • • • • • • • • • • • • • • • • • • APPENDIX B1 • DEPTH OF FLOW IN GUTTER • • • • • • • • • • • • • • • • • > 7.; 4 v m ` N $ o o tO8 2N N N Ni .- N — Ni N N C V 0 N- W 0O N pp W CN 0) C .- N 4 + N N 0) 0) 0) 7 N CV N4 M 0) O) Ts T >+ O R CO aD O) W CO CO CO W CD 0 E W W N N N N N N0CN 0 N 0 66 06 0 0 66 06 66 60 to v 0 L tid V CW o . - , , m + v m O E 0 10 CO t�) O O H Q ' A C CN+) m 10 aD CO le t t0 COaD N 0) T O 0 N N 10 O IO N N 6 t U T ^ N. N. n N. r` N N. I. r N. r- n r N. -0 al o.0 NN NN N N NN NN NN NN�y -2 6 (O t. C7 C7 11) 0) 0) 0) ) 0) 10 M C9 CO , x = 0 t0 t0 6 co CO 6 co co (0 6 6 6 6 C 0 y ® 2 • O. o o O C 5� o g 0 0 0 0 0 0 ¢ .Y E o 0 0o. o S 8o co 0 o 8o 0 0 O o 0 0 0 0 0 0 0 0 0 0 '-S .� 0 o o o O t00 t00 o U) O W 0 0 O t«/f a K O 0 C co 0)i Bao 0 0 0 0 0 00 0 c) 25 0o W co ` O o O o a o 0 0 66 0 0 Co • O . N O II m ID O O CD CO N to H CD CD ; ID CO d1 m V r t` n Is Is. OO r Is n r• r n r` N. O O G G G C G C C G C G 0 0 YO N H t iii•-•N 0 8 J 0 0 O p o O O C09 M 1 QQ tpop Of 7 17. O N O N N . b O O O - 7 66 o o O O O O o O O 66 O O Q II o C7 ¢ m ° II amax N T ' FF 1: m C p ¢ m ¢ m ,0 O. ¢ m CO W CO < CO } tom° a c C m a ^ N 0 N. on r, 0 Is ts.0 0 0 0 Is 0 Cs N.o ly p a) 2 N 0 0) i0 0 L NI 0) * U co d 0a - g+ x ° Y 15 8 0 0 .1): o < c0,_ ¢ CO. ¢ < ¢ m ¢ m ¢ m ¢ m 0 rn m $ IS CI c— ro o 17 M ,0.3., 7 0 0 p) t0 in 7 m a.0- CI V 19 w `O N N c r/3 n n r: r• co co V1 U n ' o CC cn 8 i2 ` 0.w 0 V) Co y 0) U) co y (0 (0 co m N (0 y p 11 II II II m 0Ce CD N a C Cl) T N C C • P. 4p a 4 IT a do O O O O O 0 O 0 O 0 O 0 u. p a ® 8 8 N 8 0) 100, 100, 8 W N N ® Ce W 8 8 8 0 N 1,07 8 8 8 8 8 8 C0 m 7 7 M n ® .. z W N N 7 7 p7 p�� OO p V N M tom 7 O O CO' O O N N M c§J M PO) (7 10+7 0 0 ® oo T C9 C co M co t") o ® m OOp O .:9 .NN Sco OD, GCD CO a OD, CDD 0 LO 0 e77 e7-. CO 007. ® (7 LL 07 007 M N N 007 f0I 88 88 0) 007 41) o a r ^ c``. e, m m o rt9- P. m m a v 6 0 N /V 0 N O NN H VN M p 0 N N M O Mp 8 07 8 0 C . 1110 „ r. a VN 10 7- ..+ > a 1N 00, M N (WO 100 O m M 0) r r N N N N N N 0') N N N O N .t.. a to W to to to to c0 i0 to 6 to c0 to ED O 0 Q C p 0p N m V 8 M DC N ' 0) O 8 m V tV N < M tM V M 1V N til d' M d M F . m X fil NN^ M N NN N N CDN 0Mn N N NM C C G O O O O O O G G G O O OT ill Z Ill a a - ._ Q C • e m 8 4 N S 17175 4 m 8 o 2 m '8 a O V of M r N O N N P 07 1V • -. 0) O) CD 0 CD W CO 0) 0) CD O 0) Fin, co V Z D7 2 2 (0 2 (0 2 (0 (0 2 2 0 t0 8 C O 0 O o 0 0 O 0 0 0 0 O COW .y 'E $ o S o 0 8 $ o 0 0 0 4u O O O O O O O O O O O O O O COV. C r m n O Or O O O ^ N N N O 0 0 c7 00 0o O o 00 o0 00 00 Oa cn Cl) do 0 O O o O o do O O O o O m en I I ., o 1() 47 10 N 10 10 I17 U) 10 10 47 10 N O • CO m (� r N n CO N r r N. N. r r N. O N 0 0 O O 0 0 O O O O 0 O O 0 0 OFs N tl T N 0 O ^N O O • O g 0 0 0 o Oo Po $ o g o 4 0 0 0 'J v R O 7 O N N N oD M f7 O O .� V N C C G O O " O G O O G O O O e I I O 0 m O a c E v O �+ 7 4 II II —y d 0 p ¢ `go Q m ,� m ¢ m m amD rn a a _. 7,� a c 3 co C CO a o $ $ n o o N.O ^ 0 N.0 N. N. y N CO o (n is i7 I. °o • U d O 9. O N M _ c y m e „O 8 L _ U. W m • ?L a rriY 0 0 e 0 ¢ m ¢ m < < ¢ m < m < m Q m rn m a O c— co co 0 co M 0 00 c7 m CO11') m a W w o l0 m z 0 f0 (1) (0 (1) (0 W y N (C N (0 On) ((0 fn d' m m fa I/ a C (n IT IN • • • • • • • • • • • C • • • • • • • • • • APPENDIX B2 • STORM SEWER INLET SUMMARY • • • • • • • • • • • • r Lw • • • • • • APPENDIX B2 Barracks II Phases 107 Storm Sewer Inlets on Grade - Design Analysis Inlet Length Street Q10 L10, ft. Bypass Q100 L100, ft. Bypass No. ft. Slope cfs Design cfs cfs Design cfs S710 10 1.01% 2.66 11.19 0.05 3.58 12.88 0.24 S711 10 0.60% 5.61 13.61 0.52 7.57 15.66 1.21 Assume 10%clogging for design Se =Sx+ (a/w)* Eo Eo= Qw/Q= 1 - [ 1 -W/T]2.67 L=Kc*Q0.47*So3*(1/(n*Se))0.6 W=Width of Depressed Gutter(ft) = 2 Sx=Cross flow of Road Surface 0.03 T=Total Spread of water in gutter(ft) 12.5 a=Gutter depression depth (ft)= 0.33 n=Manning's Roughness Coefficient= 0.018 Kc= 0.6 Qw=Flow in width, W E=Efficiency of inlet or percentage of interception S=Longitudinal Slope Li=Curb opening length • Se = Sx + (a/w)* Eo 0.091412 • Eo= Qw/Q = 1 - [ 1 -W/T]2•67 0.372194 41111 ir L • • • ID • • ®.rte - • - • N r CO O) C O M - r CO M 4 N • E " L r. CO• ▪ CD v/ CI L InN CC) 0 I- to '• ' 'O O 6 6 • } O • 0 T o rO) COr • �,( V v M r U - I O C r- O O CO N. c) CO I C N ONO 0 • r ._ c') 6 M u) CO u) >+ M r N co L • d 0 N M r N- r-- M .2 00 In 0) CO • 0 • N CC) co dN' V) $ N r r CO (1,--) V N O O O O a 6 6 6 6 6 6 R N • } O r 0 CO N 0 lC) �N o .r to to N. coN cor co co Tr [t Tr d N N CO ,- r- 0 CJ C') N O M d Y o r CO N O) co CO cis 7 w ccl co co <- co C O CO U) o - CO a' N 4 CO 4 E U r r 4 r.. N O R co • U C K cn 0 :8 .y rA O) r N CO c y a) C O N M N M co M O O.0 CD c N tr) N N N a +, N N N N o O O O O O O ct Q d O c C U Cd N '+ O X S. 0 .') o m O o0 O N 0 ..-L a O r N- N r .� N Cn in M d: in C „ Q `R- r o 0 Z 0 U ,--I V1 N m c6 u'1 C6 C 0 t` ti N- ti O C W o U . a • aU y • O U) Q. 2 R in y o o O 2 1 r)0 coo• `Nn 1-- L. r r r E U r r Ui r C4 5 O Q r C C y Q >, C O NDO r y d O) d a C c c EC t) = It O .� aa) d .0. = 7 2'+ N. N `° CO 0 0 CO 0 o a) a) CC N 0 0 0 0 G C Q ti ti r- n r- r O 10 O 0 . p O co 0 col O .tA m o CO +r C) . tai) d °o .S > > > > co C ._ am t C o a0) o7)= 3 .m U in > p r V co " c Z N ti CO n CO 0O E N- N- N- N- +.+ (n (n fn co to (n ec u�) Z m f/) * Q • • • • • • • • • • • • • • S • • • • • APPENDIX Cl STORM SEWER PIPE SUMMARY • • • • • • • • • • • • r • • • • • S O L o, o E V & N m m ro n m8 0m rn n 2 V O m n n V w 0 QN o N N N N 7 .4: N o NO N Ni N NQm N. ap �N� 0111 CO N 10 r 0) N CCOO, CO pp7. W co 1-4 . 7 N CCC = W Zia NI N N N N N N N N N N N N C7 N N N co C') m 7 CO.CO to et r NV, co O,is g (tpmp0� V N n fmo, URN C 7 tm0. E a LL N N N N N N N N N N N N N N N N N N N W Y , b a v CO N- m o o < m a a CO CO o m 1 n o M a> n elm R 0 me m m a 9 m 0 � � F W CMPpp N N N 80MpONNNoMpM S p 7 W O) p N M 0 CO CO O N co O O co V N N 0 8 O O O O O O N N 17 M m n n n n n n n n n n n n n n n n • t0 U) V1 CO co co co co CO co co CO CO co co CO co y co W d m .- N W N 10 O` '7 N N M a N O• QOO, • 17 10 �'J n r N N V 7 I m (d Q� m 10 n CD n m N- o a LL W O) 0) W O) Of O) O) O) W 0 0 N 0 CO W 0 O) OC N N N N N N N N N N N N N N N N N N N W W E p aa m �tpp m �{ m 2 A N 0 O n m O 8 V H CD O C)) 1D 8 D O at n C W CO P. a> N CO m co o to O 4) N O n Of Oi 14 N N 0 W O) N N N O O C �'W O O O 0 0 0 O O O W W 0 N O 0 O O CO M N N N N 17 CO CO N N N CO 0 0 CD C a d n 0n C IL' C C 7 N O) F N O N 17 '7 7 O O m N �O CO O C C U NNDm N O O N O O O N ^ N O N O r N O O y y 0 o) co CO 0 co co co co co co CO co CO co y N v . T. V N m m K CI o 0 - N N W W CO . a a a C c mm - 9o� NNm W OOOmNm bau) VmCn > a wN 7 n i.: W ad 0 o O 7 t7 O Ni Ni 14 1Vf O.a m E.) D) • A O U L ` 3 3 O o a e e e e e e e e e e e e e e e ae e e W W • CO (7 a �i v m CO N o O a s =M) o G o 0 0 0 0 o o o o o 0 G d o C m m • oo' E E L 1 pO 4 m 009 CO M N a8' K) 007. 4-4 • L 6 co �1 007 M N N N N ON 0 .- - ^ N. ` ` N- C C � fV 1V N N N N 1V O O N m i0 OD O .-N • - F€ p p .- W CO O O 0g co s 007, n O COP7 4 o m00 CO 0 o w w Z O. CO N n f� CC CO - > b ' co 7 7 ui a 7 a co 7 Cd 7 (d 0! Ci 7 7 CI CO CO m-) 05 - a n o 4 8 a 7 (mq "'m N nm, 1°0 `� < S lon cmo, 'nom. `� a o 0 W 1p (� N n �j 10 a 7 107 N N - 0 10 - N n C o N U U - m m co W - r W W o CO''' a a C. r_ T CC m • E E y pp pp pp a 4 >1 6 W M M N N CO M n M ttl O coCO4m9 f07 cococococoTh W a a CO N o0 0 o 0 0 0 0 0 0 0 7 d o 0 o d o CaNV w4 V0. C Q 2 N s 0 W ^ N O 0 O 0 mn On N O n O OM O O O 0 d J N 0 n N V 0 N N N °r 0) O O yG E E . y m co 6 co La a a W C N CO7 7 P07 9i 4i m m m m m N N N N N W co co C m _ " o ; - 0 0 Y N C C p O O to E O m N M Q l0 m O N t7 N N CO i+) l`M7 W U C o az m N'n N. N N. No N n r n N- n n n n n oLi.a m N Z.-N S - • - O t ; r r o W a aOD m � a gi chi t7 c.B , , uni 0 o m roi, =Q m ... G 6 N p O o co.o o o o o O O O O • o > 8 g) m 3 2 Mp 8p o o_ n co 3 po 2 p- pm o 4 - W N CO t0 th g N x W O O N N N CI ClQCO N N N N N CO N = 0) CO N N N • Q a a n a p O oo m 4 N N Ur o CC 2 Y pp A LL 12. J0 CO N M a o CDN N D W 6 O n n 0 0 0 n D CD COCA COCACA A W CONNN NNNNNNNNNNNNN ® a ( N 0 ° 4 � CC CD o M 2 No O vvCD u0 m m N npo0O OoNWN O , N ~W ppNDN07 C NNOOOOOO O IASI 7 aD CD O N CO a V) 0 O N CO N N 00) C') CC') o N N N O O O O O O n n r N- n n n n n n ALCM 2 U) to co co co co co co Cl) co co CO co co co co co co co Cl) 00 a CD O CO T CO CD m rN N N CN - N N 0 a n CO CO .11 am LL N- n N oi } i N NCD CA Co N CO n S) NCD n co 1 N CO A A AA CACA A CD A CACCD CDNNNN N N N N N N N N N N N N N W W m m E ` pp n CDto o O o Ute), to O OW) COD, C') U) N pO . N W CO C/▪ O m Np g N DC CA O o O O O CD co co .- o 0 CO C0O 00 OF 30 ~W t0 N co N co co CO CO CO 0) N N N 0) C) 0) CO F a 0 -6...<3. C C v NO N m o O N W a 8 O O 8 N O M O N CO iii 0 UCOn n n n Cl)n n COn CO CO CO n1 A nUN y O O T. y C,) �8 X ''e N N Z W co 4116. W m S C Q co 0 C Crn W pi. n ss- CoNN8NRNOaaVoN3NM ▪ te • OM O CD O a V a V 0 a 0 U6m V U - t 73m -o 3 o0 e eat n . CZ O O N p oca a O aN0 O fN` 0O aN m oN _ O O N N C O C rO O G G G O G O a Z.'B. m m m • m t W 2 IP Ul Ul el • mm cV N N N N N N D N N N To - E O n co D D ` N CO CO CO N CO O W CO „O„O OCO 0 V. a n CNN NN W O co O Z W,. • n• C) O CO O M a o O O 0Ucl: W W • m - E O ,e.. r O O O N N N nON N �� O - N N r N 5 " OONNNaoNM crit N cd N a N 7 a oa 8 p 0 WW y na • n- >> `m `m C m m m 4Ir r. N -a v MIMI j, S. a" g) N N N l0O tO A g) COO, o COO, g) 8 g) 8 t0O CO 8 COO, Co`v oaa N W y y o 0 0 0 0 0 0 0 0 0 o a o 0 0 0 0 0 .15 12 - Q W D1 mCO CO Ca o N 0 0C IN C ,� a G di N o o o co 0 m m ,6 U) o 8 o CI a o 0 CO N pO CN • CO O CCj 0) C6 N CO N O Cpti t OIN Q a .- 03 `� N o o r a 00 N Co N 10 N cit co E E . RI m• 0III , tit cp (p o o p C A d 6 M L a m o CO 8 (0O g) N 8 O 0 CD CD aD N `4 N N N L o N a d a (we U co co• E ad • Er.2 .N- co )0. n on tit. r on fs n n C. n �. n r- n n O••=LLC. CO N Z tNi • • • • • • • • • • S S • • • • • • • • • APPENDIX D • TECHNICAL DESIGN SUMMARY • • • • • • • • S • • • • S S • S • • • SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY The Cities of Bryan and College Station both require storm drainage design to follow these Unified Stormwater Design Guidelines. Paragraph C2 of Section III (Administration) requires submittal of a drainage report in support of the drainage plan (stormwater management plan) proposed in connection with land development projects, both site projects and subdivisions. That report may be submitted as a traditional prose report, complete with applicable maps, graphs, tables and drawings, or it may take the form of a "Technical Design Summary". The format and content for such a summary report shall be in substantial conformance with the description in this Appendix to those Guidelines. In either format the report must answer the questions (affirmative or negative) and provide, at minimum, the information prescribed in the "Technical Design Summary" in this Appendix. The Stormwater Management Technical Design Summary Report shall include several parts as listed below. The information called for in each part must be provided as applicable. In addition to the requirements for the Executive Summary, this Appendix includes several pages detailing the requirements for a Technical Design Summary Report as forms to be O completed. These are provided so that they may be copied and completed or scanned and II digitized. In addition, electronic versions of the report forms may be obtained from the City. Requirements for the means (medium) of submittal are the same as for a conventional report • as detailed in Section III of these Guidelines. • • Note: Part 1 — Executive Summary must accompany any drainage report • required to be provided in connection with any land development project, regardless of the format chosen for said report. Note: Parts 2 through 6 are to be provided via the forms provided in this Appendix. Brief statements should be included in the forms as requested, • but additional information should be attached as necessary. • Part 1 — Executive Summary Report • Part 2 — Project Administration • Part 3 — Project Characteristics O Part 4— Drainage Concept and Design Parameters Part 5— Plans and Specifications lb Part 6—Conclusions and Attestation rr • STORMWATER MANAGEMENT TECHNICAL DESIGN SUMMARY REPORT Part 1 — Executive Summary This is to be a brief prose report that must address each of the seven areas listed below. '` Ideally it will include one or more paragraphs about each item. 1. Name, address, and contact information of the engineer submitting the report, and of the land owner and developer (or applicant if not the owner or developer). The date of submittal should also be included. 2. Identification of the size and general nature of the proposed project, including any proposed project phases. This paragraph should also include reference to STORMWATER DESIGN GUIDELINES Page 1 of 26 APPENDIX. D:TECH. DESIGN SUMMARY il Effective February 2007 As Revised August 2012 SECTION IX • APPENDIX D - TECHNICAL DESIGN SUMMARY applications that are in process with either City: plat(s), site plans, zoning requests, ft or clearing/grading permits, as well as reference to any application numbers or - codes assigned by the City to such request. 3. The location of the project should be described. This should identify the Named - Regulatory Watershed(s) in which it is located, how the entire project area is situated therein, whether the property straddles a watershed or basin divide, the approximate acreage in each basin, and whether its position in the Watershed dictates use of detention design. The approximate proportion of the property in the city limits and within the ETJ is to be identified, including whether the property • straddles city jurisdictional lines. If any portion of the property is in floodplains as - described in Flood Insurance Rate Maps published by FEMA that should be - disclosed. 4. The hydrologic characteristics of the property are to be described in broad terms: existing land cover; how and where stormwater drains to and from neighboring properties; ponds or wetland areas that tend to detain or store stormwater; existing creeks, channels, and swales crossing or serving the property; all existing drainage easements (or ROW) on the property, or on neighboring properties if they service runoff to or from the property. 5. The general plan for managing stormwater in the entire project area must be outlined to include the approximate size, and extent of use, of any of the following features: storm drains coupled with streets; detention / retention facilities; buried conveyance conduit independent of streets; swales or channels; bridges or culverts; outfalls to principal watercourses or their tributaries; and treatment(s) of existing watercourses. Also, any plans for reclaiming land within floodplain areas must be outlined. 6. Coordination and permitting of stormwater matters must be addressed. This is to include any specialized coordination that has occurred or is planned with other entities (local, state, or federal). This may include agencies such as Brazos County government, the Brazos River Authority, the Texas A&M University System, the Texas Department of Transportation, the Texas Commission for Environmental Quality, the US Army Corps of Engineers, the US Environmental Protection Agency, et al. Mention must be made of any permits, agreements, or understandings that pertain to the project. 7. Reference is to be made to the full drainage report (or the Technical Design Summary Report) which the executive summary represents. The principal elements of the main report (and its length), including any maps, drawings or construction documents, should be itemized. An example statement might be: "One -page drainage report dated , one set of construction drawings ( sheets) dated , and a -page specifications document dated comprise the drainage report for this project." STORMWATER DESIGN GUIDELINES Page 2 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 2 — Project Administration Start (Page 2.1) Engineering and Design Professionals Information Engineering Firm Name and Address: Jurisdiction Schultz Engineering,LLC City: Bryan - P.O.Box 11995 ✓ College Station College Station, Tx 77842 Date of Submittal: August 2014 Lead Engineer's Name and Contact Info.(phone, e-mail,fax): Other: IR Joseph P. Schultz,PE email:joeschultz84@verizon.net Phone: 764-3900 fax: 764-3910 Supporting Engineering/Consulting Firm(s): Other contacts: n/a Developer/ Owner/Applicant Information Developer/Applicant Name and Address: Phone and e-mail: Heath Phillips Investments,LLC 979-690-5000 3302 General Parkway College Station, TX 77845 Property Owner(s) if not Developer/ Applicant(&address): Phone and e-mail: • Project Identification Development Name:The Barracks II Subdivision,Phases 107 • 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 8 of 13 Legal description of subject property (phase)or Project Area: (see Section II, Paragraph B-3a) 1116 Crawford Burnett League,A-7 I 4 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. Housing construction is complete and on-going in the previous phases(Sections 103, 104, 105,106, 108& 300) General Location of Project Area, or subject property(phase): Between Old Welborn Road and Holleman Dr.South,North of Rock Prairie Road West and South of Cain Rd In City Limits? Extraterritorial Jurisdiction (acreage): Bryan: acres. Bryan: College Station: College Station: 7.654 acres. Acreage Outside ETJ: STORMWATER DESIGN GUIDELINES Page 3 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY Part 2 — Project Administration Continued (page 2.2) Project Identification (continued) Roadways abutting or within Project Area or Abutting tracts, platted land, or built subject property: developments: Old Wellborn Rd The Barracks Section 106 Holleman Drive South Named Regulatory Watercourse(s) &Watershed(s): Tributary Basin(s): Bee Creek Trib B.3 Plat Information For Project or Subject Property (or Phase) Preliminary Plat File#: 14-00900010 Final Plat File#: A'/A Date:June 2014 Name: THE BARRACKS II(PP) Status and Vol/Pg: submitted with this project If two plats, second name: File#: Status: Date: Zoning Information For Project or Subject Property (or Phase) Zoning Type: PDD Existing or Proposed? Existing Case Code: Case Date Status: Zoning Type: Existing or Proposed? Case Code: Case Date Status: Stormwater Management Planning For Project or Subject Property (or Phase) Planning Conference(s)& Date(s): Participants: N/A Preliminary Report Required? N/A Submittal Date Review Date Review Comments Addressed? Yes No In Writing? When? Compliance With Preliminary Drainage Report. Briefly describe (or attach documentation explaining)any deviation(s)from provisions of Preliminary Drainage Report, if any. STORMWATER DESIGN GUIDELINES Page 4 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY Part 2 — Proiect 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 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 with Summarize need(s) &actions taken (include contacts &dates): TxDOT Needed? Yes No411 ✓ Coordination with Summarize need(s) & actions taken (include contacts&dates): - TAMUS Needed? Yes No ✓ 4 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. EntityPermitted or Status of Actions (include dates) Approved ? US Army Crops of Permitted Permit approve& Engineers No Yes ✓ US Environmental Protection Agency No ✓ Yes Texas Commission on Approved NOI for entire Subdivision Environmental Quality No Yes ✓ Brazos River Authority No if Yes STORMWATER DESIGN GUIDELINES Page 5 of 26 APPENDIX. D:TECH. DESIGN SUMMARY IEffective February 2007 As Revised August 2012 SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY Part 3 — Property Characteristics Start (Page 3.1) Nature and Scope of Proposed Work Existing: Land proposed for development currently used, including extent of impervious cover? Proposed development is residential subdivision. High density.Impervious cover=75% Redevelopment of one platted lot, or two or more adjoining platted lots. Site Development Building on a single platted lot of undeveloped land. Project Building on two or more platted adjoining lots of undeveloped land. (select all Building on a single lot, or adjoining lots, where proposed plat will not form applicable) a new street(but may include ROW dedication to existing streets). Other(explain): Subdivision Construction of streets and utilities to serve one or more platted lots. Development ✓ 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 63 lots. Approximately 1890'of Streets. Proposed Project 2.24 ac. -ROW Is any work planned on land that is not platted If yes, explain: or on land for which platting is not pending? ✓ No Yes FEMA Floodplains Is any part of subject property abutting a Named Regulatory Watercourse No Yes ✓ (Section II, Paragraph B1)or a tributary thereof? Is any part of subject property in floodplain No ✓ Yes Rate Map area of a FEMA-regulated watercourse? Encroachment(s) Encroachment purpose(s): Building site(s) Road crossing(s) into Floodplain areas planned? Utility crossing(s) Other(explain): No ✓ Yes If floodplain areas not shown on Rate Maps, has work been done toward amending the FEMA- approved Flood Study to define allowable encroachments in proposed areas? Explain. STORMWATER DESIGN GUIDELINES Page 6 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 3 — Property Characteristics Continued (Page 3.2) Hydrologic Attributes of Subject Property (or Phase) Has an earlier hydrologic analysis been done for larger area including subject property? Reference the study (&date)here, and attach copy if not already in City files. Yes ✓ Kimley-Horn Study(July 2012&Revised September 2013)-Analyzed downstream flooding potential and detention pond design. 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. If property is part of multi-phase project, provide overview of stormwater management plan for Project Area here. In Part 4 describe how plan for subject property will comply therewith. Do existing topographic features on subject property store or detain runoff? ✓ No Yes Describe them (include approximate size, volume, outfall, model, etc). Any known drainage or flooding problems in areas near subject property? No ✓ Yes • Identify: • The area around Cain Road and Old Wellborn Road. Based on location of study property in a watershed, is Type 1 Detention (flood control) needed? (see Table B-1 in Appendix B) Already Provided in previous phase ✓ Detention is required. Need must be evaluated. Detention not required. II What decision has been reached? By whom? If the need for How was determination made? Type 1 Detention must be evaluated: I STORMWATER DESIGN GUIDELINES Page 7 of 26 APPENDIX. D:TECH.As Rev DESIGNed SUMMARY Effective February 2007 SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY Part 3 — Property Characteristics Continued (Page 3.3) Hydrologic Attributes of Subject Property (or Phase) (continued) Does subject property straddle a Watershed or Basin divide? ✓ No Yes If yes, describe splits below. In Part 4 describe design concept for handling this. Watershed or Basin Larger acreage Lesser acreage Above-Project Areas(Section II, Paragraph B3-a) Does Project Area (project or phase) receive runoff from upland areas? No ✓ Yes Size(s)of area(s)in acres: 1) 2.52 2) 3) 4) Flow Characteristics(each instance)(overland sheet, shallow concentrated, recognizable concentrated section(s), small creek(non-regulatory), regulatory Watercourse or tributary); Each instance is overland sheet flow and shallow concentrated flow. Flow determination: Outline hydrologic methods and assumptions: Rational Equation. C-values 0.75 for Developed Lot Areas, 0.65 for Developed Park Areas, 0.45 for Undeveloped Areas 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 in runoff characteristics subject to change in future? Explain Yes.As adjoining tracts develop and install detention ponds,their outflows will be conveyed through this tract by the proposed storm sewer. Conveyance Pathways (Section II, Paragraph C2) Must runoff from study property drain across lower properties before reaching a Regulatory Watercourse or tributary? ✓ No Yes Describe length and characteristics of each conveyance pathway(s). Include ownership of property(ies). STORMWATER DESIGN GUIDELINES Page 8 of 26 APPENDIX. D:TECH.As Revised DESIGN SUMMARYugust Effective February 2007 SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY Part 3 — Property Characteristics Continued (Page 3.4) Hydrologic Attributes of Subject Property (or Phase) (continued) Conveyance Pathways (continued) Do drainage If yes, for what part of length? % Created by? plat, or easements instrument. If instrument(s), describe their provisions. exist for any part of pathway(s)? ✓ No Yes Where runoff must cross lower properties, describe characteristics of abutting lower property(ies). (Existing watercourses? Easement or Consent aquired?) Existing watercourse crosses the downstream properties.See Kimley Horn Report Pathway Areas Describe any built or improved drainage facilities existing near the property (culverts, bridges, lined channels, buried conduit, swales, detention ponds, etc). Detention Ponds constructed with previous phases. Nearby Drainage Do any of these have hydrologic or hydraulic influence on proposed stormwater Facilities design? No / Yes If yes, explain: See Kimley Horn Report,Phase 100 Report by Phillips Engineering and Phases 101-104& 300 Report by Goodwin-Lasiter,Inc. • • • • • 11111, 1 STORMWATER DESIGN GUIDELINES Page 9 of 26 APPENDIX. D:TECH. DESIGN SUMMARY s Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Start (Page 4.1) Stormwater Management Concept Discharge(s) From Upland Area(s) If runoff is to be received from upland areas, what design drainage features will be used to accommodate it and insure it is not blocked by future development? Describe for each area, flow section, or discharge point. Runoff from upland areas will be captured in publicly owned storm drain systems as the subdivision develops. Discharge(s)To Lower Property(ies) (Section II, Paragraph El) Does project include drainage features(existing or future) proposed to become public via platting? No ✓ Yes Separate Instrument? ✓ No _ Yes Per Guidelines reference above, how will Establishing Easements(Scenario 1) runoff be discharged to neighboring ✓ Pre-development Release(Scenario 2) property(ies)? Combination of the two Scenarios Scenario 1: If easements are proposed, describe where needed, and provide status of actions on each. (Attached Exhibit# Scenario 2: Provide general description of how release(s)will be managed to pre-development conditions(detention, sheet flow, partially concentrated, etc.). (Attached Exhibit# Detention Pond. Combination: If combination is proposed, explain how discharge will differ from pre- development conditions at the property line for each area (or point)of release. If Scenario 2, or Combination are to be used, has proposed design been coordinated with owner(s)of receiving property(ies)? ✓ No Yes Explain and provide documentation. STORMWATER DESIGN GUIDELINES Page 10 of 26 APPENDIX. D:TECH.As RevisedN SUMMARY Effective February 2007 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4— Drainage Concept and Design Parameters Continued (Page 4.2) Stormwater Management Concept (continued) Within Project Area Of Multi-Phase Project Identify gaining Basins or Watersheds and acres shifting: Will project result in shifting runoff between Basins or between What design and mitigation is used to compensate for increased runoff Watersheds? from gaining basin or watershed? ✓ No Yes How will runoff from Project 1. With facility(ies)involving other development projects. Area be mitigated to pre- 2 Establishing features to serve overall Project Area. development conditions? Select any or all of 1, 2, 3. ✓ On phase(or site) project basis within Project Area. ® and/or 3, and explain below. ® 1. Shared facility(type &location of facility; design drainage area served; relationship to size of • Project Area): (Attached Exhibit# ) 2. For Overall Project Area (type&location of facilities): (Attached Exhibit#A Existing detention ponds will serve the proposed development. it, 3. By phase(or site) project: Describe planned mitigation measures for phases(or sites) in subsequent questions of this Part. Are aquatic echosystems proposed? No Yes In which phase(s)or project(s)? c.. •ID c >- Are other Best Management Practices for reducing stormwater pollutants proposed? co b_ No ✓ Yes Summarize type of BMP and extent of use: tr Silt fences, construction exits, rock check dams,seeding and erosion matting. a) o z If design of any runoff-handling facilities deviate from provisions of B-CS Technical a✓ Specifications, check type facility(ies)and explain in later questions. co Detention elements Conduit elements Channel features N Swales Ditches Inlets Valley gutters Outfalls Culvert features Bridges Other STORMWATER DESIGN GUIDELINES Page 11 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY 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). 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): The detention ponds constructed with the previous phases will serve this phase. Runoff will enter the pond through the underground storm drains. Within Or Serving Subject Property (Phase, or Site) If property part of larger Project Area, is design in substantial conformance with earlier analysis and report for larger area? ✓ Yes No, then summarize the difference(s): Identify whether each of the types of drainage features listed below are included, extent of use, and general characteristics. Typical shape? Surfaces? �• V-Channel Grass Lined a; rn Steepest side slopes: Usual front slopes: Usual back slopes: >- 2:1 2:1 4:1 1 Flow line slopes: least 1.00 Typical distance from travelway: a) typical 1.00 greatest 5.00 (Attached Exhibit#B -a 0 z CD • 2 Are longitudinal culvert ends in compliance with B-CS Standard Specifications? I Yes No, then explain: Q c, At intersections or otherwise, do valley gutters cross arterial or collector streets? I No Yes If yes explain: U -C3 uAre valley gutters proposed to cross any street away from an intersection? io I No Yes Explain: (number of locations?) '� z STORMWATER DESIGN GUIDELINES Page 12 of 26 APPENDIX. D:TECH.As Revised SUMMARY Effective February 2007 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.4) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site)(continued) Gutter line slopes: Least 0.60 Usual 0.60 Greatest 1.01 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. c- a) D Will inlet size and placement prevent exceeding allowable water spread for 10-year design storm throughout site(or phase)? ✓ Yes No If no, explain. Y 0) '' S Sagcurves: Are inlets placed at low points? ✓ Yes �f No Are inlets and - E conduit sized to prevent 100-year stormflow from ponding at greater than 24 inches? 0 o✓ Yes No Explain "no" answers. a) El?. 71; 22 Will 100-yr stormflow be contained in combination of ROW and buried conduit on Q 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. limo Are any 12-inch laterals used? ✓ No Yes Identify length(s) and where - used. ID -. a) Pipe runs between system Typical 135' Longest 809' - access points(feet): - ,r,✓ Are junction boxes used at each bend? ✓ Yes No If not, explain where and why. c to (1 z o - • E Are downstream soffits at or below upstream soffits? Least amount that hydraulic a) Yes ✓ No If not, explain where and why: grade line is below gutter line (system-wide): 0.71' (10-Yr Storm) STORMWATER DESIGN GUIDELINES Page 13 of 26 APPENDIX. D:TECH.As RevisedN SUM 1ARY 2012 Effective February 2007 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.5) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site)(continued) Describe watercourse(s), or system(s) receiving system discharge(s) below (include design discharge velocity, and angle between converging flow lines). U 1) Watercourse (or system), velocity, and angle? Bee Creek Trib B.3 @ 0°,<2 fps E 2) Watercourse (or system),velocity, and angle? O p o E - 3)Watercourse (or system), velocity, and angle? � -a 0 L 0 Q E -- For each outfall above, what measures are taken to prevent erosion or scour of o r receiving and all facilities at juncture? 1) Outfall from this development will occur into downstream pipes from prey.phases L cu 2) 0 3) Are swale(s) situated along property lines between properties? ✓ No Yes Number of instances: For each instance answer the following questions. Surface treatments(including low-flow flumes if any): �. 411 cn a� } Flow line slopes(minimum and maximum): • 4111 o NZ Outfall characteristics for each (velocity, convergent angle, &end treatment). c�a✓ co co 2 Will 100-year design storm runoff be contained within easement(s)or platted drainage ROW in all instances? Yes No If"no" explain: 4 0 STORMWATER DESIGN GUIDELINES Page 14 of 26 APPENDIX. D:TECH.As RevisedN SUMMARY Effective February 2007 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4— Drainage Concept and Design Parameters Continued (Page 4.6) Stormwater Management Concept (continued) Within Or Serving Subject Property(Phase, or Site)(continued) Are roadside ditches used? No I Yes If so, provide the following: LIs 25-year flow contained with 6 inches of freeboard throughout ? .1 Yes No 1-2 Are top of banks separated from road shoulders 2 feet or more? Yes I No a) Are all ditch sections trapezoidal and at least 1.5 feet deep? Yes I No For any"no"answers provide location(s)and explain: cn oThe existing ditch along Old Welborn Road is a V-Channel that does not allow for the ditch to • be trapezoidal or to be separated from the road shoulders. 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? Yes No If "no" explain: O o co Space for 100-year storm flow? ROW Easement Width z c Swale Surface type, minimum Conduit Type and size, minimum and maximum 1/ c and maximum slopes: slopes, design storm: 0 co -0 T) al Inlets Describe how conduit is loaded (from streets/storm drains, inlets by type): O 0 c� @ s O 0. o Access Describe how maintenance access is provided (to swale, into conduit): o : c� . o • L a - o --a) , Instance 2 Describe general location, approximate length: . 7 a� coE 411 z Is 100-year design flow contained in conduit/swale combination? Yes No 411 0 o If "no" explain: 411 � E Space for 100-year storm flow? ROW Easement Width U 0 Swale Surface type, minimum Conduit Type and size, minimum and maximum 410 5 co and maximum slopes: slopes, design storm: C CO aInlets Describe how conduit is loaded (from streets/storm drains, inlets by type): 3 0 Access Describe how maintenance access is provided (to swale, into conduit): ( STORMWATER DESIGN GUIDELINES Page 15 of 26 APPENDIX. D:TECH.As Revised DESIGN SUMMAugust RY Effective February 2007 SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.7) Stormwater Management Concept(continued) Within Or Serving Subject Property (Phase, or Site)(continued) If"yes" provide the following information for each instance: Instance 1 Describe general location, approximate length, surfacing: Co. n. E w Is 100-year design flow contained in swale? Yes No Is swale wholly o• >_ within drainage ROW? Yes No Explain "no" answers: W ) v Access Describe how maintenance access is provide: o Z 0 Instance 2 Describe general location, approximate length, surfacing: m o E 3 m Is 100-year design flow contained in swale? Yes No Is swale wholly m �' within drainage ROW? Yes No Explain "no" answers: o O c Access Describe how maintenance access is provided: .U_ 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: 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 3 describe section shape &area, flow line slope(min. &max.), surfaces, and 100-year wdesign flow, and amount of freeboard: o_ Instance 1: • • o a� E m r o Instance 2: a E o � z I • E ✓ Instance 3: U STORMWATER DESIGN GUIDELINES Page 16 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.8) Stormwater Management Concept(continued) Within Or Serving Subject Property(Phase, or Site)(continued) Existing channels (small creeks): Are these used? ✓ No Yes If"yes" provide the information below. Will small creeks and their floodplains remain undisturbed? Yes No How many disturbance instances? Identify each planned location: For each location, describe length and general type of proposed improvement (including floodplain changes): For each location, describe section shape & area,flow line slope(min. &max.), surfaces, and 100-year design flow. a) a Watercourses (and tributaries): Aside from fringe changes, are Regulatory Watercourses proposed to be altered? ✓ No Yes Explain below. c Submit full report describing proposed changes to Regulatory Watercourses. Address °) existing and proposed section size and shape, surfaces, alignment,flow line changes, length affected, and capacity, and provide full documentation of analysis procedures ° and data. Is full report submitted? Yes No If"no" explain: a E m co All Proposed Channel Work: For all proposed channel work, provide information requested in next three boxes. If design is to replicate natural channel, identify location and length here, and describe design in Special Design section of this Part of Report. Will 100-year flow be contained with one foot of freeboard? Yes No If not, identify location and explain: Are ROW/easements sized to contain channel and required maintenance space? Yes No if not, identify location(s) and explain: r STORMWATER DESIGN GUIDELINES Page 17 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY ® Part 4— Drainage Concept and Design Parameters Continued (Page 4.9) Stormwater Management Concept (continued) • Within Or Serving Subject Property (Phase, or Site)(continued) How many facilities for subject property project? For each provide info. below. For each dry-type facilitiy: Facility 1 Facility 2 Acres served & design volume+ 10% 100-yr volume:free flow& plugged Design discharge(10 yr & 25 yr) Spillway crest at 100-yr WSE? yes no yes no Berms 6 inches above plugged WSE? yes no yes no Explain any"no" answers: a) >- For each facility what is 25-yr design Q, and design of outlet structure? Facility 1: 0 z Facility 2: Do outlets and spillways discharge into a public facility in easement or ROW? Facility 1: Yes No Facility 2: Yes No -0' If"no"explain: a) U) 0 Q. 0 a For each, what is velocity of 25-yr design discharge at outlet? & at spillway? a Facility 1: & Facility 2: & F- r) Are energy dissipation measures used? No Yes Describe type and u_ location: 0 c a) For each, is spillway surface treatment other than concrete? Yes or no, and describe: Facility 1: Facility 2: For each, what measures are taken to prevent erosion or scour at receiving facility? Facility 1: Facility 2: If berms are used give heights, slopes and surface treatments of sides. Facility 1: Facility 2: STORMWATER DESIGN GUIDELINES Page 18 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY Part 4— Drainage Concept and Design Parameters Continued (Page 4.10) Stormwater Management Concept (continued) Within Or Serving Subject Property(Phase, or Site)(continued) Do structures comply with B-CS Specifications? Yes or no, and explain if"no": a) Facility 1; a) :62 5 Facility 2: o c o U iv For additional facilities provide all same information on a separate sheet. 0 Are parking areas to be used for detention? No Yes What is maximum depth due to required design storm? Roadside Ditches:Will culverts serve access driveways at roadside ditches? No Yes If"yes", provide information in next two boxes. Will 25-yr.flow pass without flowing over driveway in all cases? Yes No Without causing flowing or standing water on public roadway? Yes No Designs&materials comply with B-CS Technical Specifications? Yes No Explain any"no" answers: ui oAre culverts parallel to public roadway alignment? Yes No Explain: P • Q Creeks at Private Drives: Do private driveways, drives, or streets cross drainage • o ways that serve Above-Project areas or are in public easements/ ROW? 11111N z No Yes If"yes" provide information below. ,/ How many instances? Describe location and provide information below. • > Location 1: • > U Location 2: Location 3: For each location enter value for: 1 2 3 0 Vs Design year passing without toping travelway? Water depth on travelway at 25-year flow? Water depth on travelway at 100-year flow? For more instances describe location and same information on separate sheet. STORMWATER DESIGN GUIDELINES Page 19 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY Part 4— Drainage Concept and Design Parameters Continued (Page 4.11) Stormwater Management Concept(continued) 1111 Within Or Serving Subject Property (Phase, or Site)(continued) Named Regulatory Watercourses (&Tributaries): Are culverts proposed on these • facilities? ✓ No Yes, then provide full report documenting assumptions, ® criteria, analysis, computer programs, and study findings that support proposed design(s). Is report provided? Yes No If"no", explain: ID al Arterial or Major Collector Streets: Will culverts serve these types of roadways? -c I No Yes How many instances? For each identify the a location and provide the information below. a a3 Instance 1: >- a °' Instance 2: c o Instance 3: o o m Yes or No for the 100-year design flow: 1 2 3 z E `o Headwater WSE 1 foot below lowest curb top? N Spread of headwater within ROW or easement? E y Is velocity limited per conditions(Table C-11)? N Explain any"no" answer(s): O c C o RS U • o Minor Collector or Local Streets: Will culverts serve these types of streets? n No Yes How many instances? for each identify the location and provide the information below: • Q. N Instance 1: 411 0 c Instance 2: • m co o Instance 3: cFor each instance enter value, or"yes"/"no"for: 1 2 3 ;, y Design yr. headwater WSE 1 ft. below curb top? • < .- 100-yr. max. depth at street crown 2 feet or less? • E Product of velocity(fps) &depth at crown (ft) = ? Is velocity limited per conditions(Table C-11)? Limit of down stream analysis(feet)? Explain any "no" answers: STORMWATER DESIGN GUIDELINES Page 20 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.12) Stormwater Management Concept(continued) • Within Or Serving Subject Property (Phase, or Site) (continued) ID All Proposed Culverts: For all proposed culvert facilities(except driveway/roadside ® ditch intersects) provide information requested in next eight boxes. Do culverts and travelways intersect at 90 degrees? Yes No If not, ® identify location(s)and intersect angle(s), and justify the design(s): 0 Does drainage way alignment change within or near limits of culvert and surfaced m-- approaches thereto? No Yes If"yes"identify location(s), describe change(s), and justification: Are flumes or conduit to discharge into culvert barrel(s)? No Yes If yes, identify location(s) and provide justification: Are flumes or conduit to discharge into or near surfaced approaches to culvert ends? No Yes If"yes" identify location(s), describe outfall design treatment(s): c - o 1111 > Is scour/erosion protection provided to ensure long term stability of culvert structural 4111 components, and surfacing at culvert ends? Yes No If"no" Identify - locations and provide justification(s): 411 • - Will 100-yr flow and spread of backwater be fully contained in street ROW, and/or - drainage easements/ ROW? Yes No if not, why not? i Do appreciable hydraulic effects of any culvert extend downstream or upstream to iill neighboring land(s) not encompassed in subject property? No Yes If "yes"describe location(s)and mitigation measures: i Are all culvert designs and materials in compliance with B-CS Tech. Specifications? Yes No If not, explain in Special Design Section of this Part. STORMWATER DESIGN GUIDELINES Page 21 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.13) Stormwater Management Concept(continued) Within Or Serving Subject Property (Phase, or Site)(continued) Is a bridge included in plans for subject property project? ✓ No Yes If"yes" provide the following information. Name(s)and functional classification of the roadway(s)? What drainage way(s) is to be crossed? a) 0 ML W A full report supporting all aspects of the proposed bridge(s) (structural, geotechnical, hydrologic, and hydraulic factors)must accompany this summary report. Is the report provided? Yes _No If"no" explain: Is a Stormwater Provide a general description of planned techniques: Pollution Prevention rock riprap,silt fence installation and inlet protection To Plan (SW3P) C� established for project construction? No ✓ Yes Special Designs—Non-Traditional Methods Are any non-traditional methods(aquatic echosystems, wetland-type detention, natural stream replication, BMPs for water quality, etc.) proposed for any aspect of subject property project? I No Yes If"yes" list general type and location below. • • • • Provide full report about the proposed special design(s) including rationale for use and expected benefits. Report must substantiate that stormwater management objectives will not be compromised, and that maintenance cost will not exceed those of traditional design solution(s). Is report provided? Yes No If"no"explain: C STORMWATER DESIGN GUIDELINES Page 22 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.14) Stormwater Management Concept(continued) Within Or Serving Subject Property (Phase, or Site)(continued) Special Designs—Deviation From B-CS Technical Specifications If any design(s)or material(s)of traditional runoff-handling facilities deviate from provisions of B-CS Technical Specifications, check type facility(ies) and explain by specific detail element. Detention elements Drain system elements Channel features Culvert features Swales Ditches Inlets Outfalls Valley gutters Bridges(explain in bridge report) In table below briefly identify specific element,justification for deviation(s). Specific Detail Element Justification for Deviation (attach additional sheets if needed) 1) 2) 3) 4) 5) Have elements been coordinated with the City Engineer or her/his designee? For each item above provide"yes"or"no", action date, and staff name: 1) 2) • 3) 4) L 5) • Design Parameters Hydrology Is a map(s) showing all Design Drainage Areas provided? ✓ Yes No S Briefly summarize the range of applications made of the Rational Formula: - Pipe Design,Inlet Design and Gutter Depth Check low What is the size and location of largest Design Drainage Area to which the Rational Formula has been applied? 4.64 acres Location (or identifier): 816 r , STORMWATER DESIGN GUIDELINES Page 23 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.15) Design Parameters(continued) Hydrology(continued) In making determinations for time of concentration, was segment analysis used? No ✓ Yes In approximately what percent of Design Drainage Areas? 100 13/0 As to intensity-duration-frequency and rain depth criteria for determining runoff flows, were any criteria other than those provided in these Guidelines used? ✓ No 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 10& 100 10 Storm drain system for local streets 10& 100 10 Open channels N/A N/A Swale/buried conduit combination in lieu of channel N/A N/A Swales N/A N/A Roadside ditches and culverts serving them N/A N/A Detention facilities: spillway crest and its outfall N/A N/A Detention facilities: outlet and conveyance structure(s) N/A N/A Detention facilities: volume when outlet plugged N/A NM dO Culverts serving private drives or streets N/A NM ID Culverts serving public roadways N/A N/A Bridges: provide in bridge report. NM N/A • Hydraulics • What is the range of design flow velocities as outlined below? ID Design flow velocities; Gutters Conduit Culverts Swales Channels • Highest(feet per second) 3.18 9.12 N/A N/A N/A Lowest(feet per second) 1.48 1.89 N/A N/A NM Streets and Storm Drain Systems Provide the summary information outlined below: *■+ Roughness coefficients used: For street gutters: 0.018 For conduit type(s) RCP HDPE Coefficients: 0.013 0.013 STORMWATER DESIGN GUIDELINES Page 24 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.16) Design Parameters(continued) Hydraulics(continued) Street and Storm Drain Systems (continued) For the following, are assumptions other than allowable per Guidelines? Inlet coefficients? ✓ No Yes Head and friction losses I No Yes Explain any"yes" answer: In conduit is velocity generally increased in the downstream direction? I Yes No Are elevation drops provided at inlets, manholes, and junction boxes? I Yes No Explain any "no"answers: Are hydraulic grade lines calculated and shown for design storm? ✓ Yes No For 100-year flow conditions? I Yes No Explain any"no" answers: What tailwater conditions were assumed at outfall point(s)of the storm drain system? Identify each location and explain: Yes, the storm drain system was designed taking into account a tail water of 292.0'. Open Channels If a HEC analysis is utilized, does it follow Sec VI.F.5.a? Yes No Outside of straight sections, is flow regime within limits of sub-critical flow? Yes No If"no" list locations and explain: - Culverts If plan sheets do not provide the following for each culvert, describe it here. F For each design discharge, will operation be outlet(barrel)control or inlet control? r C Entrance,friction and exit losses: Bridges Provide all in bridge report 0••• STORMWATER DESIGN GUIDELINES Page 25 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.17) Design Parameters (continued) Computer Software What computer software has been used in the analysis and assessment of stormwater ® management needs and/or the development of facility designs proposed for subject property project? List them below, being sure to identify the software name and version, the date of the ® version, any applicable patches and the publisher Excel spreadsheets,Autodesk Civil 3D Storm Sewer Analysis and Hydroflow 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: The storm sewer system and detention facilities are designed in accordance with the BCS 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 Part B was prepared by me (or under my supervision) in accordance with provisions of the Bryan/College Station Unified Drainage Design Guidelines for the owners of the property. All licenses and permits required by any and all state and federal regulatory agencies for the izQ used drainage improvements have been sued +r fall under applicable general per : oF: ? , 4 .,_ ASIA (D. (A ffix Sealy'� ' � � �_ � ff (3 9 . F�® S�� I 1 ® EttV oo� 0 �.. 1-7 Licensed 'rofessional Engineer ' l f ':' " R F; E State of Texas PE No. 6.s" ri� !� `-��: S6V fi/0-f$7e . mss l Sy `� ( N: STORMWATER DESIGN GUIDELINES Page 26 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012