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HomeMy WebLinkAboutWESTBURY PUD, SECOND FILING - FINAL - 11-94B - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT103 S. $TEWART$,ASSOCIATE$ PH 82-9 3D1RF X 482-9382,UM, FORT 0LLINS, CO 80521 Consulting Engineers and Surveyors 3y: i %,� Date: 3 Zo 'i Client: /�Q t /-i n d e. r' Sheet No. of Project: W/eS-�bury - P VD -S c.and Subject: FrOSiOh Cohlrol L/—,oa er4 �3ovE 1 i`bITCH T.T. _.�Lo�} o� f --. d, lCti .._....Lei 'r\._I - I— le. �barriersl is `-°--� 1-- -- - —'— -- - �-- � -L°-- _ �r3S0 I I i I I --►IS U_ e� FJ elf YOU I ! c�.`��I_ :`G�._ 1 Q I I rz = L ..A i I , ili�l! ! I i� 111 I-II..�11..I- I. I CONSTRUCTION SEQUENCE PROJECT: V✓ES1 t3y2Y YV D 2 STANDARD FORM C SEQUENCE. FOR 19 qS ONLY COMPLETED BY: DATE: 3 w 9 5 Indicate by use of a bar line or symbols when erosion control measures will be installed. Major modifications to an approved schedule may require submitting a new schedule for approval by the City Engineer. YEAR 15 I MONTH 1- I s 1,4 15 1 0 1 Al p I ---------------------------- OVERLOT GRADING T-------------------7 T 1 'I I --------T I ---j I ---T I ---j I -- ---� WIND EROSION'CONTROL Soil Roughing Perimeter Barrier Additional Barriers Vegetative Methods Soil Sealant Other curb s RAINFALL EROSION CONTROL STRUCTURAL: . Sediment Trap/Basin Inlet Filters Straw Barriers Silt Fence Barriers Sand Bags Bare Soil Preparation Contour Furrows Terracing Asphalt/Concrete Paving Other Gvrbs VEGETATIVE: Permanent Seed Planting Mulching/Sealant Temporary Seed Planting Sod Installation Nettings/Mats/Blankets Other ---------------------------------T- STRUCTURES: INSTALLED BY MAINTAINED BY VEGETATION/MULCHING CONTRACTOR DATE SUBMITTED APPROVED BY CITY OF FORT COLLINS ON HDI/SF-C:1989 JANUA -1 199 L 8-20 DESIGN CRITER-TA EFFECTIVENESS CALCULATIONS --------------------------- ------------------------------------ PROJECT: %A/EST3(/IZ)/ PVP SEGUwD F)LINc— STANDARD FORM B /�RE/i H[30VE 017CH COMPLETED BY: DATE: 3 20 '�5 MAJOR! BASIN ARE/a gBOVE 7rCH Erosion Control C-Factor Method Value Bare Spi seed <�C- iudl c4 ( Ic v+- 0 �o + ;e i l+c�ra P> UO 0., 0 r 1.00 .5+r-aw bclrrlerS 1.0 0 rvMt cvrbS 0.01 PS M 80. G P-Factor Value Comment I v r -------------------- r_oG' U. �B (100 --------------------------------------------------------- SUB AREA BASIN (Ac) CALCULATIONS ---- ------ 5.92 pv,�4- Gvr bs U, 75 Ac se e vl 61, Z. 3 0 oc bore so i % 2, G7 A-- G _ �0.95)60.01)4- (2.30)(0.06) 4+ 67)6 s,9Z c : o, 4-e r-- 0.S,x 0.S- = 0,4 Seed G, � M vl ��, re -or c70 U�- all lugs s l I------------------------------------------------ ---------------------- HDI/SF-B:1989 EFFECTIVENESS CALCULATIONS --------------------------------- ----- ---------------------------- PROJECT: `.JES rlsuRY Pt/D SEGOND FILWC- STANDARD FORM B ARE.+ aeLvvI 171Tc4 COMPLETED BY: DATE: Erosion Control C-Factor P-Factor Method Value Value Comment ----------------------- B are Svl ------ i 4-Mvl, h -- /.06 ---o ---------------------- /-00 .5ecj- pond. 0.06 /.00 1 0 -6• j0 s }roll ✓ b a rn e rf inlet f-IIIerS 1. 0 v v. £l0 1.00 �vr�f cvl�I 0.61 I.00 MAJORI PS SUB AREA ----------- ----------- BASIN (%) BASIN (Ac) CALCULATIONS ----- 4REA ------ ----- ------ --------------- cvrhi Zoo AC aet,ow 7y.8 IU,SG see24-L'I�/' .3.Z0 Ar- P17cN bare so i S, 0 6 10,56 G =, s0' �= c).a-x0.i = a.4 Fr- X.-50) jX100 EFr Sect Avl CA CArN re- or- �Grdl Z-45 Z ( 3 J ork? SS- 5-7 e ---------------------- ------------------------------------------------i )I/SF-B:1989 '• RAINFALL PERFORMANCE STANDARD EVALUATION --------------------------------------------------------------------- PROJECT: 1n/E 57(3 u )zY P(/D SCGO,vb FILING- STANDARD FORM A COMPLETED BY: DATE: 20 qS --------------------------------------------------------------------- DEVELOPED ERODIOI.LITY Asb Lsb Ssb Lb Sb PS SUBBASIN ZONE (ac) (ft)• (%)_ (feet) M ( ) ------- 13/a51 �✓ --------- N h ----- 5.9Z ------ � 5�0 -- - Z --- ---- ------ - ---�--- 80• Rf3oVE nV f Cc D ITCH Pi/a5/N1 13 Edo IJ D1 iC14 415 h 1 W-36 1 11,5 7 77.6 I I --------------------- iu�t i�c_.r•inan EROS CONTROL 0 PO1410S of 'n' 0000 0000000 /00 .000/ 80 0. 90. . ... .. 70 e 78' 1.0004 0001 1 60?. I1' •0003 ae. 66' SO ao 60' OOOS 25 40 'fv- S4' .0006 9'B. 48' ..0008 0009 y 30 ?. '42' .001 3 p 0 i 10 `�.v. 33' .001 3.5 �O. lb "o. 30. y .003 .. o ?�. 17' o .00a 4 P. - .006 C 005 y aVi /0 . :00D 5 8 y S.S LZ 7 15 6 j FN t /11.p .04 Z , (y .os �s I 4. moo. /0. .06 8 .07 I .08 .09 9 /0 1 s. .1 Z .3 4 S ; 4' .6 .7 .8 Fig. 15. Diagram for the solution of IGl.ter's formula for circular pipes flow- ing full. COMPUTATIONS _ Stewart & Associates, Inc. 103 5. MELDRUM Sf. Ft. Collins, CO 80521 C' P_ 3 Date `Chkd By: Date (303) 482-9331 Client: Sheet No. of Project: Subject �LL0W�BLE GU��Q�LOW - LOC�L ST�E��IN/TIAL STO�M(Z�R)GU��R�LOW - LOC�L STKE��- 1AUT/AL STORM(Z YR) I_ �.,� I i I I crossi Isi per' z .I ..I ..,. 6 v�b� ve ! � � I I j C�? = 1 q• G Z �i 3 1-7 SD�• 1` SLoF E.7- I ' .... __. I I III , i l l 11 sed n Zd'w .. _ v oi. -io 'L Z �' ir I I .... i j I I I�! i A. //0'Q b1 e, Q �•5 I I I I /12,Iz►js . );3,I3 I I; I�. i0 7 t I f 17,.e /. �• 6 i I ��,18 I I, I. .0 8 I I► 5. d� f i i /.I- ! I i z . I + v.6' /6.3 tit I I I i 1 ' I ;o, 6 7.4 s I i +z.0 4j31 ! I c I Ief cT� i •�2! 2IL d� G eye 20.G.Y'S c,�� S.0 !; sB�SI I i I i 0.¢i8 i. G-Oi I 421 i , ! i �!6�g cis! o ¢5 Tor. I I. or33 I I C�c�s! �� Ill i i ,IiII ty ij I II11 ,,; Ili I I I i !�i+Ili! III I`i' I IIiI� ' COMPUTATIONS Stewart & Associates, Inc. 103 S. MELDRUM s.. Ft. Collins, CO 80521 (303) 482 9331 zy: F'1 R Date - Client: Sheet No. of Chkd By: Date Project: Subject ALLOW,y13LE 1=LOW IN LOCAL STgae-rs — l UU Yo sTOFZM . I i � � •� I i ' i 41� y I ! I I2 (( s ¢ o,s -� 0,)(�. ¢ i 5' I I i .5 CFI ! I. i Z Zp 6 035 _(I1 �9% ii4A , 5�) ,A .OZ. i� �..-. i o I I IQ r -call I7�e v �o� Fo���rl I,LLOKIMIE Q 77-101 cfs U • 7 1%u .. . 1131!, Z U.r(! o1 1rf.;Zc)'S It.•{�!T�i �. � 167. 6 cft I I 0I7Zd . 4 Iqq� I ��o 18S S I I. i.. 0.6 UB) 1 I y �' G c 1 c-�s 1 I ' z.q''%v ! � I 9-8.� I �7l'-� I � I• s I I ! ' i I1862'c;s 3.(✓°;o � I � � I ; --1. 2 I I i 19s;6 cff ,. 3.5� I I I 'Z97.7j i. I j � S; i 1Y019 c; s 314-Q. i a I ¢ I s33.b ( /8 �..51.ciji + c.Ti0 (9f-.6•'0 J53.8 cf 1.0 7 B. 0 7, g'15.4 i i I I i0.33 7 i I ; i37.0 ciS - 1 Z2.0 c -�5 STEWART&ASSOCIATES 10 82 9 3DIRUM,FAX FORT COLLINS, CO 80521 PH.82 Consulting Engineers and Surveyors By: P 19 Date: Client: inia lK L i ^ Ir Sheet No. _ r I Project: \n/e S-rDL, Subject: Die _ e ^ � of -II ...__'__I . ,... _..-._._ _ _.. ._ i _ ._... _ � _..I. _.._ i.._�.�,. 15 cM� ( tlniUER S. sNIELDS IsT. �_ I IReleaSt- I¢, . _I_._� I III II I Ii(i il�_�i I I /00` I S�OI �I Ip.�� I I 1 1 I ,�77C iv IS;�/C�a!`l I'^�rC^T'j fS reon i^�e� S�77-1 cio w� re o.-� w G, I (` CrZ,I 77�2 �L 4, lot 032 JA �IJ31 Ov��Gi 12 ( I ! ! I 13 3!= a.032 z i I+ ! + I� 4 S, 52,34� V.�7.2 BPS i I/� rleo. t fl> 1:Z3I .1)(17•Z� = e, �I - 00ee", _ i 1-GS�r 1 (,2, iph I a� �P a I- I 44 -I 91 -oil r I i i i I UM STEWART& SSOCIATES PH. 82-93311RFAX 482-938OLLINS, CO 80521 Consulting Engineers and Surveyors By: p J 1� Date: s 2 d 4 S" Client: o rK L i n �� /' Sheet No. _ of Project: V e-s iD U r (% D Subject: Ca�ci ci 4 o� FTODOSC< �G�C^tl Oh o0-5 i P P o / Berl �v`4 I. Ii _.. ........... . _.. I ... 0 tl' V -Ar ec Ii 177,.7 01 I !_ ...._._ .._. _.._ _._..__...._.._..�....�_........-ff..__!..._...._ L.._! I.._ -��,, L-_ L__!_ i_._}_ �__ ( I I 1f ' , 81 - ZS f I 7 �. 6 sa2�iDC- U _ I _ 1 , L-I 15-7 0'0I �� I I I 1 i_..I.I 13,Z31F1{c,F, �3.04-�1�Ff.l STEWART&ASSOCIATES Consulting Engineers and Surveyors 103 S. MELDRUM, FORT COLLINS, CO 80521 PH. 482-9331 FAX 482-9382 By: p ) I� Date: 3 2r/ Client: M a roc L f hG�e r Sheet No. —of Project: Subject: �'—O n. c e-n n!-f �.- I6r�).51n/ _i' (%-- 11 Gv-� I I �LoW I GCio 12101 I I pr►elT I �.-. 20..Gt.S , + I STEWART&ASSOCIATES 103 82-9 3DIRUM,FAX FORT gOLLINS, CO 80521 PH.Consulting Engineers and Surveyors �1 / By: P) Date: 3 2 `1 S� Client: AA a ✓ �c L Sheet No. —of 1 / � Project: `,./ G 14 U✓ y Fy p 2 n! Subject: C O h c P n -Lra ` (7 n >o k,4S ?,U�-.I_ =._ 3�37._.c+-S_._ ... _.. . L.. _. i I Qio 1= 121 3I3! 3.`a�i ! GIUII Gi4 I I _{ -f- 7 e4- _ I2,C?Ui _. TY 0r-=: I )20 j IVS r %a ! 31p �' r{�C U . ! Oi✓ j �v I.SLO�/L TU�_._! i�lE-rFn/i-1110 G%� I &I -T I _ 13 r a IU i�►Y, y t I�--I--, -+--f - -i--1 D is G1__.. /lv i. Pa Ic 4 I lot ! I I(rir ! „✓es_ veer 1. ! ' L. I d ire i L_.-- i I I.._. , _ CZ Il. (7 ! 9L + + - ' 17�'Z3 I ii.o3_I_�h7�C_ itGGO-- I 05iEl I is i 6 A P, 4CI7 Y Gr-7 I P I � (JS£ r9 Z9 i_v1v--- 1 .---s�rrPE._._�.-rd _ Gf+-rCbk F3 /a 511n/ ,cIIYY1.z 19 e.pf I I l0 v Y� aVF_T? -L ! I STEWART&ASSOCIATES 10 82 9 3DiRF , FORT gOLLINS, CO 80521 PH.Consulting Engineers and Surveyors I By: F� 1, / Date: 3 2. v � Client: /�� ��C L I n de ►� Sheet No. of Project: W e S� b V r y ? V p 2 h--� Subject: I I 7.7 --c; AT�>+_.�.13;>4S IN._ ._�!►Tra I-- (- PlPF_ 12 P t lvs .!ITarl 1.27.241 t 7--------- _.. _ ...I_.. _.._ Gtcv� tz4:�4.1.7 PA IITy.—= 17 �lU z.Z3 _ cis qq I _..0 S F ¢ C14 : 64-I- � S'�N-- �.JLV4 �'_GA4'r U-f f' f,- c _. _(� C..P _..I.�'i!_. _l _ _S.!�.. iC.iS�ro, </?�ert��c j J ! I I STEWART&ASSOCIATES Consulting Engineers and Surveyors 103 S. MELDRUM, FORT COLLINS, CO 80521 PH. 482-9331 FAX 482-9382 Project: `,, e Date: 3 2 G r Client: Sheet No. _ of UfV p Lip 2ni Subject: G4 rl C-cP n'i f G �l G h �O 1 ✓' *1 1 ¢ _ (Ras a.,� � �r!•or� I i I-�rs4- IIM�o� 14 I E'Ivsl .Fdik!t�... I .i p1IV earl / �I I vws I _ f F .�'ror; . e tn/e I ✓cs S IZv��. U r I 1i D� e-I ✓� . _,__.. ._. I (3asinl of t n 44 S. I 9 I �1 - ow - - - --1 - ��o.__ - '— - Go✓1ce�/ — __� ._ Gi-1 I c�, '- J .1 - I , j C IGv � .1170:..c G121 + 27 1 . STEWART&ASSOCIATES 10 82 933DiRUM, FAX FORT gOLLINS, CO 80521 PH.Consulting Engineers and Surveyors . By: [7 I''%� // r � Date: 3 20 S� Client: /ylo. rk Li � � e w Sheet No. _ of Project: �/ e 5 D V f 2 n� Subject: n ror. I rest ( GL,1�f- ( �— 3 IVJ I h I0�/ r0i'.. e-ols ' SWc-le .0� li✓CIIT� Vr�Y F. It-f 1 ! - I topic IZlsi� lle r'1 I I i i I I! — _ I -- - ``� tov I I I P raf'�._.._�__. -.-- --I--- _- I � � I.l 9-�'� �v;.C� �� 0•r/�l �Z._� � i 3. o.' �Pl .L._ 0 -Y- - — .. — -- — - - 3.3 a. - -.. �01 i2,¢4 r l___,__ -_.- --__I ____ __� .__�_-.- _- -.__ __�_�_l.�_._►__�_ __.�___ __l_.._1__L ._. STEWART&ASSOCIATES 103 S- 482-933MELDRUM1, FORT COLLINS, CO 80521 PH. FAX 482-9382 Consulting Engineers and Surveyors By: P l E Date: Client: Sheet No. —of Project: \-xJe-J U, Subject: C 0 k7 C-e I/no 611, . 1- r a'^-, -4-1 j� i 73^S�Al . I C"at o T I.3, c 14 L'AT9 OF--, I i i lu lei I - i I-- I- I ------ I Conc �I Ic�lpo//"-p _n, vs 0 If I�T 1 �__ _t_.I I�� J/ 0 F s ,,,, --- 4-0 ILI— �t IV ------ 1 C11 V�- 7— )-5— ex as /0 I .i T-1 id c-rpxAiAY?-rJZAr,,r,.(-)rwF c 103 482-9331 S. MELDRUMFAX 482-938, FORT COLLINS, CO 80521 PH. 2 Consulting Engineers and Surveyors By: PIT< Date: 3J20/ 9 Client: Zihdey- Sheet No. of Project: W Cs i p U r V Subject: a. .5 i U c 3 Y 13' c STEWART&O SSOCIATES 103 . MEL 1RF , FORT gOLLINS, CO 80521 PH.Consulting Engineers and Surveyors By: P 1 R Date: 3 2 U 9 Client: 114o r tC L! eld C l— Sheet No. of _ Project: W/ fJJ_b (J V V Zf Subject: Gt S l n C l C L/ N69 }►c Plvr z.7 �� o T-'sy�c i �o:r iase 4.34 I I 1�_ (2.IS�Co.2io�1+�/�4/)�(/ !)}(o.---�U.29. I I /4.I _. ._ o. 29i ►. f 13 �.ic1 :�s)�4.�?��__� 1_1_1 1- -E-t— III STEWART&ASSOCIATES 103 . MELD1RUM,FAX FORT COLLINS, CO 80521 PH.Consulting Engineers and Surveyors By: .P 1 TZ 1 Date: 3 Z° 9 s Client: M oa ik L ! , �e � Sheet No. _ Project: w/ es4 y r p U 2 Subject: 6 a S i,1 'f a l c v t OJ/ o nI of I- —� --- 1e I - U iTie I � I I STEWART&ASSOCIATES 103 . MELD1RUM,FAX FORT COLLINS, CO 80521 PH.Consulting Engineers and Surveyors By: p L Date: 3 Lf/ 4 Client: /OGt ri< b h Je r Sheet No. _ of _ rtcl Project: 'de, S y r-V p U E-2 / 2 Subject: b a S l n G C � G �! G-r!G h S F . . I 0.6 A. 1 I STEWART&ALSSOCIATES 10 S. 938 RUM,FAX FORT COLLINS, CO 80521 Consulting Engineers and Surveyors By: Pf /E LL Date: Client: MC' rk L?n j er Sheet No. —of _ Project: �✓ �U U I- V D 2 n Subject: �ci.Sln Ga��C.v�a.�lunl ire. l q �-<0 0.9 � )(G esI ! _ vls 9 ` i ( I ,.I let GZI_rua. I ds S9�1_¢ l_v�_q G._7 :..----�-33 3.3f -Gr 1 I _ ' /-it-at e -lf�_ _ 'IO.7 t4.4 - -- ___lD G� j G 2s� i{_O_¢1) 0 - G � I I L 2d;U {}I _:�`i',.. � I 7= lS3 i•^��. i i I, I /4•¢tU —�- - } ;...�GI;4 10.- f d _o_tsy.C.•_.?_.-�)C_!.._G,7 2-o6_.s_.__.�_ __�_._ i r --j—---- STEWART&ASSOCIATES Consulting Engineers and Surveyors 103 S. MELDRUM, FORT COLLINS, CO 80521 PH. 482-9331 FAX 482-9382 By: Pl R< Date: 3 2v 9 i Project: W es4-� u ry P UL Client: /V(o rt-c t f'n c1 e ! Sheet No. of Subject: 13 a 5%n Z0-1 C(vi aJioHJ ;0.21y +; o•3e(� °I� U,7i ._' ..... --- .... C1.73 g o 9_, i9' TC; a J l I 3 /4 c I G l _p�-_�-- -1I i I i Vb c )_ � � 11 STEWART$,kSSOCIATES Consulting Engineers and Surveyors 103 S. MELDRUM, FORT COLLINS, CO 80521 PH. 482-9331 FAX 482-9882 By: 1 J? / I Date: 32 v! 9� Project: w G 3 '-b V r- U Client: MorL, Li n d e-r-' Sheet No. _ of hd Subject: )sot 5/h Cct/ Gv_i(,x4-I oh I 179j : / ,S - I _ l G Tc- . _ (• �17 I I.1. _, 7 q sv _! ...6t.. t �. G�l.,/r_i_= _.._I (1J.7 �C. �9 • C_.1, ! 3..; _-._ ._..._r¢ • l_0.__� G (& GF!:_G!/I - �I.25�(0.71) I I �_�_i� I�_ : I1. OU,.A , - � I IG — _�C1.34%� • S� .��.G; �. a ! r i I i - l . � I , -- j.GCtW��._C1FUla jQlh..=.!¢.2 - ' : 0.�t)I( 9 I! I - { STEWART&tSSOCIATES 10 S. MEL9331DRUM,FAX FORT COLLINS, CO 80521 82 Consulting Engineers and Surveyors By: Y 1 TZ Date: 3 Zfr 9 i Client: /✓%a r� L t e r Sheet No. of Project: k✓e s -� b uo-y % (/ Subject: ,�' Gt S1 13�-jS/N. ;s I fie, I0-11-10 _ eas�.l SWria��C i �L�. 3 33 STEWART&\SSOCIATES 10 82 9 3DRUM, FAX FORT gOLLINS, CO 80521 PH.Consulting Engineers and Surveyors "� By: / %Z Date: 3 Client: / �' /� L / / c�P r Sheet No. —of Project: "�/ &J v C- y V Z n Subject: /3 cZ.s i �, Ca cvl cji c� K r STEWART&tSSOCIATES 103 48S. MELDRUM2-9331, FORT COLLINS, CO 80521 PH. FAX 482-9382 Consulting Engineers and Surveyors By: Date: 3.1.2al.'?5' Client: MatL Sheet No. of T--T-- Project: l)e5 -�b Vr-x ecc-" F-; 1 P, Subject: Q, I C.(, ------ )1Ieli I 54- S )el2sr Yr- rie r7 0 7-4 F -- - . i . -- - --- ! - .. -.1— --- ------ OIL- n The well �bere r I 30I- .. I �n� b, s/� I_ e e, 0 T-� e- e- g 10 5- 2i 0,1)-,-, 0.00 10-45Y I I I l _�-_, ;-1, �-.� _ /,r�_j-- -� _.I .. -. �_ 0 I _-� i.-. _ I .1 _; i- 0 �5.1-- x Z- -7- r . ..... .... .1- Z1, C-T - 1 I. ;>?i CH.��4}��.S,zL--I._1_q�_5,Z I I 6e f0c, -7 1 0.0 arlMc._._CGZIAM.���.j�_.I _��/��'c_.j_.L._I L J- - I �I�14�I,,I_ ' T STEWART&OtSSOCIATES 103 . MELDiRUM,FAX FORT COLLINS, CO 80521 PH.82 Consulting Engineers and Surveyors 11 By: �) Date: � � Client: / Y 1 a L_ r ri< H dto r Sheet No. _ of Project: Je-5�( �i V r y �l CIS S ecd�- E) Pfi, Ir r I Subject: 045,ITC' /4)00f, )'1(;;tr+^1Ony %{e-1 cv, He Z)',C.QZO t ... ¢•S _ - I- I ......... Ii Ih I � .__ _ . -iL - I - --�- - ---... --- - - --�-- — -- -- 7 O U SU 17 U� 1 Tc- l Fr7 I 1• -.3 F�.+_4 �. _.31.�+4,7rS,� Z I .306�(Lz.2 [.3l•7 I �GZ(ui �.�._. c. - U. - ��-- I.2�, 0;30� i[ 35 (_3I.7.; _ _ ¢Z�¢ *-r-- - - Thl-s sI/Rio+ rw, v)y .h-- / Z -. U� �ar � �Oa w�i G� (_G:DU�C—I-� P� 1- )r da��- i 1/'�hi . ��+ as+i1 10_ e s V!- 0- o v F.vlg LG - d-� ��, Div'__. e _ex s. rni r✓>,.�' __. to (f. e . _ fire) na h e�sfI ) corn - f7hf GTA 00 1of_�'"_.L3Ll.00,ere zAvis {7 'b rt Sc e4-Lll- 1/ev�P10 �I- f--� — I a ie /o�n-- 1 I 71-074 �lY MUST_ _P�ss 13 I -1- --t FLo,v✓__.. aV7 --- -.-..__._Z3.. y- pr7?,S DF -- STEWART$,ASSOCIATES 103 S. PH. 82-93311RCOLLINS, CO 80521 FAX 482-938 Consulting Engineers and Surveyors By: P / �I Date: 6 G Client: /O o r-4 LI n de % Sheet No. of Project:yk/ eII S 7 I V p y p l/ p Subject: De 7�C'r` ) o h PC n 5 i 7- i' n5 7 6 /' _ i OTC) 2_ A C S lie -,--. I �_._� I I...�. .-. i I I_ L _�._.I j /ive�a�� -� } ci = CSSod v. 9S t- �raG��U. i O� ¢9 ST . i Ni�ssl L�,I AGz AIMI �Ir TIIaDI �` f ,RF-1 �=ASIF I.1�ATe .Z-YR IN-ISiTOM Ci= .4-.4— Ic75--�--- _ . G _ T . { _ lwcwr��. _ I �' ._._. 7 i. G�G/� __ ! C>? 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I Z .7 i 2,7 1 3 0.Lx (0 �Tc-el 60, a C)) Cb - 'T) z- ) 6 5- Q C11 (/) ( I. wo 6A 6? ic4 8Jfsi- cxlb):e e, c' I�I�ill) jii�I!�.!. if i(Ill lil�!Ilj I Westbury Second Filing Page 2 Runoff from the basins and critical point flows are shown on the calculation sheets in this report. EROSION: The Westbury development is located in a high rainfall erodibility zone and in a moderate wind erodibility zone. The Second Filing consists of 5.92 acres above the PV & LC ditch and 10.56 acres below the ditch. The area below the ditch will drain to the detention pond where a sediment trap shall be installed. Grading will take place on the area above the ditch before the bridge and curbs are constructed to carry flows across the ditch; so a temporary flow cutoff ditch and berm will be placed along the west side of the PV & LC ditch to intercept flows and sediment. The detention pond area and disturbed portions of rear yards will be seeded and mulched. Straw bales will be placed along the swale on the north side of Lots 1 through 14 and along the swales through the detention pond. Gravel inlet filters will be placed around all catch basins and sidewalk culverts. The 200 foot barrier spacing for wind erosion control will be provided by the curbs and rainfall erosion control procedures. All erosion control measures shall comply with City of Fort Collins Criteria. WESTBURY SECOND FILING SITE LOCATION AND INFORMATION Westbury Second Filing is a 16.48 acre tract located in the Northeast 1/4 of Section 3, Township 6 North, Range 69 West of the Sixth P.M., City of Fort Collins, County of Larimer, State of Colorado. The site is about 600 feet south of Harmony Road and borders the west side of Shields Street. Westbury First Filing lies between the site and Harmony Road. OFFSITE FLOWS: The total runoff from Westbury First Filing enters the Second Filing along Westbury Drive and also a small amount enters from the drainage easement at the east side of the First Filing. This runoff from the First Filing includes runoff generated by the First Filing and also runoff from the 3.1 acre tract lying immediately west of the First Filing and also runoff from The Ridge development and Harmony Road to the west of the Pleasant Valley and Lake Canal ditch. Calculations of these offsite flows are shown on the calculation sheets in this report. The 100 year offsite flow form the 3.1 acre tract plus The Ridge is calculated to be 47.5 c.f.s.. This flow shall be routed between Lots 2 and 3 of the First Filing to Westbury Drive, where it will flow south to the Second Filing. SECOND FILING DRAINAGE: Runoff from the First Filing shall be routed through the Second Filing to a detention pond to be constructed along the west side of Shields Street. This detention pond is sized to detain for both Westbury First and Second Filings, with a release equal to the 2 year historic runoff from the total site area of 24.5 acres. Calculations of the release rate and required pond volume are included in the calculation sheets. Release from the pond will be through a restricted outlet into the existing 15 inch CMP under Shields Street. Offsite flows from the Ridge and other areas to the west will overflow the pond and Shields Street and then be carried to the east across the Larimer Community College in an existing swale which was constructed for the Westbury outflow. This swale is in a 20 foot easement and will carry 50.6 c.f.s. before overtopping. SECOND FILING DESIGN: Runoff generated by the Second Filing will be carried by the streets and storm drain piping to the detention pond, except for the rear yards of Lots 40, 41, 42, 43, 47, 48, 49, 50, 51, 52, 53 and 54, which will drain directly into the PV & LC ditch. Also, runoff from the pavement via Shields Street and the Shields and Westbury intersection cannot enter the detention pond since the high water line of the pond is approximately 1.5 feet above the curb flow line at this intersection. The Second Filing is divided into 13 basins, and the runoff from each of these basins, as well as the combined flows at critical points, are shown on the plan included with this report. No Text Westbury P. U. D. Page 4 Erosion will be controlled in the swales by placing straw bale barriers, and a sediment trap will be placed over the detention pond outlet. Also, the paved streets shall be cleaned and straw bale barriers shall be placed between the developed lots and the temporary detention pond. Wind erosion will be controlled by the curbs and pavement and by the rainfall erosion control procedures. Erosion control procedures shall comply with the City of Fort Collins Criteria. Westbury P.U.D. Page 3 A berm will be constructed along the north, ponding area, and the existing vegetation in the maintained as much as practical. The shape and be revised as necessary when drainage design is final buildout of all the.filings. east and south sides of the bottom of the pond will be size of this ponding area will done for future sizing, at The existing 15 inch CMP under South Shields Street will remain as is until future widening construction of South Shields Street takes place. This 15 inch CMP is at the low point in the borrow ditch, and it must remain open to carry borrow ditch flows from both the north and south. The Westbury detention pond outlet pipe, which.is a 12 inch diameter pipe with a 9 inch diameter restricted opening, will release into the west borrow ditch of South Shields Street where the flow will combine with the borrow ditch flows from the north and south. These flows will then drain under South Shields Street through the existing 15 inch CMP and also through an existing 15 inch RCP which is located about 70 feet south of. the 15 inch CMP. The invert of the 15 inch RCP is approximately 1 foot higher than that of the 15 inch CMP, so ponding occurs before the 15 inch RCP is utilized. These existing 15 inch pipes:outflow on the east side of South Shields Street onto the property of the Front Range Community College. An easement has been obtained from the school districts to allow the swales and storm flows to cross the school property. Copies of this easement and agreement are included with this report. The east portion of the swale system across the Community College property is already in place by construction about ten years ago. This existing swale system is around the college parking lots and to the east to tie into the Mail Creek drainageway. A new swale will be constructed from drainage under�Shields Street to this existing swale. The release from the Westbury detention pond will be 4.4 c.f.s. which will be added to existing offsite flows from the Thayer property to the south and the Gress Gallery property to the north. These combined flows then cross under Shields Street in the two 15—inch pipes and then through the swale system. The calculated maximum flow through the two 15—inch pipes is 16.6 c.f.s. If the Thayer property and Gress Gallery property develop, their allowable runoff will be reduced to.the 2—year historic amount. EROSION CONTROL The Westbury P.U.D. site is located in a high. rainfall erodibility zone, and in a moderate wind erodibility zone. The 8.1—acre First Filing will be .developed at this time, and the existing vegetation will be maintained on the remainder of the site, except in the area of sanitary sewer construction and the construction of the berm around the detention pond. The berm will be seeded and mulched. The concrete and paving will be installed to provide erosion protection, and the disturbed portions of the rear yards of the lots will be seeded and mulched. Westbury P.U.D. Page 2 9. There is a possibility that storms greater than the 100—year occurrence will overflow Shields Street, but the downstream swales across the community college property will accommodate additional flows without causing damage to buildings. 10. An existing irrigation lateral site from west to east will be rerouted This pipe will exit the east side of Lot easement across the site. SITE LOCATION AND EXISTING CONDITION which crosses the north side of the around the housing in a 12—inch pipe. 15 and will be located in a platted Westbury P.U.D. is a 24.5—acre site located in the Northeast '—, of Section 3, Township 6 North, Range 69 West, of the Sixth P.M., Fort Collins, Colorado. The site is "L" shaped and touches West Harmony Road on the north and South Shields Street on the east. The undeveloped Thayer property lies to the south; and the Ridge, which is a developed subdivision of large residential lots and open spaces, is to the west. Also to the west is a 3.1—acre single —residence tract. The 7—acre Gress Gallery property is located in the "L" to the east and north. This site has only three residential —type buildings and no paved streets, so we have considered it undeveloped, with a C.of 0.20. The Pleasant Valley and Lake Canal ditch crosses the property in a northwest to southeast direction, and development of that portion of Westbury lying west of the ditch will require a bridged street crossing. That design will be a part of future filings. The existing site is covered with heavy natural grass and alfalfa vegetation. All that part of the site located east of the Pleasant Valley and Lake Canal ditch, including the offsite 3.1—acre single —residence tract, drains to an existing ponding area located along the west side of South Shields Street at the southeast corner of the Westbury site. The existing Shields Street roadway is raised and provides the dike for this ponding area. Outflow from the ponding area is under Shields Street to the east through an existing 15—inch CMP and an existing 15—inch RCP. PROPOSED DRAINAGE A temporary detention pond will be constructed in the existing ponding area located at the southeast corner of the Westbury site. The release rate from this pond will be the 2—year historic runoff from the total 24.5—acre Westbury site, which is calculated to be 4.4 c.f.s. A temporary easement will be dedicated on the unplatted portion of Westbury for this temporary pond and the flow route from the First Filing to the pond._.. „ The total .volume of the permanent detention pond will not be constructed for development of the First Filing. A temporary pond will be sized to hold the developed runoff from the Westbury First Filing, plus the existing, undeveloped runoff from the 3.1—acre offsite single —residence tract, plus the 10.12—acre undeveloped portion of the Westbury site lying east of the Pleasant Valley and Lake Canal ditch. We presume no existing flows from the west will cross the Pleasant Valley and Lake Canal ditch. The volume required for the First Filing pond is 62457 cubic feet, or 1.43 acre feet. DRAINAGE AND EROSION CONTROL REPORT WESTBURY P.U.D. GENERAL DRAINAGE INFORMATION ABOUT SITE 1. The McClellands and Mail Creek Major Drainageway Plan applies to this site. The site is located along the southern edge of the basin. 2. There are no major basin improvements planned in the vicinity of the site. 3. Stormwater release rates permitted in this basin are 2—year historic flows. 4. The upstream offsite basins consist of 4.1 acres of three (3) large residential lots and open space in the Ridge subdivision, and of a 3.1—acre single —residence tract. The 4.1 acres in the Ridge is existing development, and there is a possibility the 3.1—acre tract may be developed into additional residential lots. 5. There are no release rate restrictions on the Ridge property; and, should the 3.1—acre tract be developed, it will require detention and will be restricted to a 2—year historic release rate. The runoff from the Ridge and from the existing 3.1—acre tract will be routed through the. Westbury development via sideline lot easements. 6. The Westbury development will match existing grades on adjoining sites, and positive flow will be maintained from the adjoining sites. 7. The Pleasant Valley and Lake Canal ditch crosses the Westbury site, and runoff from new hardsurfaced areas will be carried across the ditch on a proposed street crossing bridge. (This bridge will be part of a future filing.) 8. There is an existing well—defined drainage route leaving the site. This drainage crosses under South Shields Street in two existing 15—inch pipes. The flow is then across the Front Range Community College property across a meadow in sheet flow to an existing drainage swale around the college parking lots. This swale was constructed by the college about ten years ago. It carries offsite flows as well as parking lot runoff to the. Mail Creek channel. The runoff from the two 15—inch pipes which now sheet flows across the meadow will be placed in a channel which will carry it to the south side of the college property and then easterly along this south side until it turns north to the existing swale around the parking lots. There is a dedicated easement for this drainage Swale from Shields Street to Mail Creek, and a copy of this easement is included in the appendix. Construction of the Westbury development will not increase the downstream runoff quantity, although the total volume of runoff will increase due to more hard surfacing. The proposed detention ponding on the Westbury site will control flows so that downstream conditions will not be impacted. STEWART&ASSOCIATES Consulting Engineers and Surveyors March 20, 1995 Mr. Basil Hamdan Stormwater Utility City of Fort Collins P.O. Box 580 Fort Collins, CO 80522 Dear Basil: The following drainage and erosion control report for Westbury Second Filing is an addition to the report prepared in September of 1994 for Westbury First Filing. The narrative portion of the 1994 report is included immediately following this cover letter since it provides information about the total Westbury site. The paved portion of South Shields Street and the east 100 feet of Westbury Drive is lower than the proposed 100 year high water line of the detention pond, so this area will not be piped into the pond but instead will go directly into the outlet pipe under Shields Street. Also, the back portion of Lots 40, 41, 42, 43, 47, 48, 49, 50, 51, 52, 53 and 54 will drain directly into the Pleasant Valley and Lake Canal ditch. The developer has received approval from the ditch company to release this runoff directly into the ditch. A variance from the City Storm Drainage Criteria is hereby requested to release these flows undetained. The design and calculations of storm drainage and erosion control for Westbury Second Filing complies with City of Fort Collins Criteria. Sincerely, Phillip I. Robinson, P.E. & L.S. Vice President rsc James H. Stewart and Associates, Inc. 103 S. Meldrum Street P.O. Box 429 Ft. Collins, CO 80522 303/482-9331 Fax 303/482-9382 FINAL STORM DRAINAGE REPORT FOR WESTBURY P.U.D. SECOND FILING PREPARED FOR MARK LINDER PREPARED BY STEWART & ASSOCIATES, INC. 103 SOUTH MELDRUM STREET FORT COLLINS, COLORADO 80521 303/482-9331 MARCH 20, 1995 10