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Home My WebLink AboutDrainage Reports - 05/07/1996FINAL STORM DRAINAGE and EROSION CONTROL REPORT DUPLEX CONSTRUCTION UNIT "B" 629-112 SOUTH MELDRUM STREET CITY OF FORT COLLINS, CO February 16, 1996 Prepared For: Jim Schmid 401 West Mulberry Street Fort Collins, CO 80521 (970) 221-0700 Prepared By: Structured Engineering 31 8 East Oak Street Fort Collins, Colorado, 80524 Phone (970) 495-0810 Fax (970) 224-1314 , ovecl Report at,e ~ /tLCJc FINAL STORM DRAINAGE and EROSION CONTROL REPORT DUPLEX CONSTRUCTION UNIT "B" 629-112 SOUTH MELDRUM STREET CITY OF FORT COLLINS, CO February 16, 1996 Prepared For: Jim Schmid 401 West Mulberry Street Fort Collins, CO 80521 (970) 221-0700 Prepared By: Structured Engineering 318 East Oak Street Fort Collins, Colorado, 80524 Phone (970) 495-0810 Fax (970) 224-1314 February 16, 1996 Mr. Bas i l Hamden Stormwater Utility City of Fort Collins PO Box 580 Fort Collins, Colorado 80522 Dear Basil, Attached is the Final Storm Drainage Report that accompanies the construction of a single duplex located in the Old Town drainage basin at 629-112 South Meldrum Street. All design is in conformance with the latest edition of the City of Fort Collins' Storm Drainage Design Criteria and Construction Standards. ~,~,'iet~~ ·"••····· ~ "' ·=' ~1 Josep t~'!/J"AJ~~~ ~ Structured Engine r . ' ~--- Vi ne Drive INTRODUCTION FINAL STORM DRAINAGE and EROSION CONTROL REPORT for Duplex Construction -Unit B 629-112 South Meldrum February1 6, 1996 A single duplex is proposed for construction on a residential lot within the Old Town Drainage Basin between Laurel and Myrtle Streets at 629-112 South Meldrum. 629 Meldrum is an existing one story frame house residence. This report sums up the analysis that was undertaken to determine what, if any, impacts the proposed construction will have on the historical drainage patterns in each area. The report will address the following: 1 .Site Descriptions 2.Storm Drainage A. Design Criteria B. Hydrology C. Conformance With Existing Master Drainage Plans 3. Erosion Control A. Erosion Control Measures It is intended that the recommendations found in this report become an integral part of the design and construction phases of the project. 1. SITE DESCRIPTION The property is also known as Lot 9 of Block 86 of the City of Fort Collins. The area is established and mature with landscaping and an older house. The duplex site will be in the back half, or western part, of the lot. With the exception of a water service installation, little disruption is planned for the front half of the lot. Existing lot grading is at approximately . 5 %, generally from the back, (west) of the lot towards the middle. The Arthur Ditch traverses the front of the lot between the existing residence and Meldrum Street. It is below grade and enclosed in a concrete box culvert. Alleys along the west and south lot lines are paved. The alleys are of the inverted crown type and have inverted pans down the center. Drainage from the alleys is collected in a catch basin at the intersection of the two alleys and is discharged into the Arthur Ditch culvert. The only other existing drainage improvements immediately adjacent to the site is curb and gutter along Meldrum Street. There are no pronounced natural drainage features on the site. The soils group making up both sites are primarily ML and CL-ML according to the Larimer County Soils Survey by the Soil Conservation Service. STORM DRAINAGE A . Design Criteria The City of Fort Collins has prepared a Storm Drainage Design Criteria and Construction Standards (SDDC) which provides the basis for the analysis used in predicting storm runoff and the recommended drainage improvements. B. Hydrology The Rational Method is used to predict the amount of runoff . The 100-year return frequency was used in this report to predict major peak discharges, and 2- year storm is analyzed to predict minor flows. C. Conformance With Existing Master Drainage Plans The Old Town Master Drainage Piao was prepared for the City of Fort Collins by RCE Engineers on January 7, 1 993. RCE assumed a runoff coefficient of .60 for the area proposed for construction of the duplexes. According to the Stormwater Utility , if the percentage of imperviousness of a deve l oped si t e is less than the 60% assumed by RCE in their report, then on -site detention is not required. Calculations included with this report confirm that the site has an imperviousness percentage less than 60%, hence detention is not analyzed nor provided. .3... EROSION CONTROL The SDDC outlines the causes and results of soil erosion due to wind and rain. Because each site is less than 1 acre in size, they are exempt from wind eros ion control requirements. Along with the requ i rements of this report and the erosion control plans, the SDDC shall be considered in it's entirety for guidelines to aid i n preventing rainfall soil erosion. The SDDC will govern requirements and specifications for earth moving at the construction site . A cost estimate for erosion control measures is included with this report. SUMMARY OF STORM DRAINAGE AND EROSION CONTROL MEASURES The following is a summary of the storm drainage improvements and erosion control measures that are to be observed during construction. GENERAL EROSION CONTROL NOTES 1. Keep disturbed areas to a reasonable minimum at any one time. 2. Stabilize all disturbed areas. 3. Keep runoff to velocities not causing erosion. 4. Provide diversion channels to direct runoff around and away from disturbed areas. 5. Keep all cut and fill slopes stabilized with terracing or scarifying furrows perpendicular to the slope . 6. Protect stockpiled materials from wind erosion. Stockpiles are not to be higher than 8'. 7. Permanent groun d cover is to be established on all disturbed areas. Areas to be seeded which have been compacted by construction activities are to be ripped or otherwise loosened prior to seeding. 8. Provide a temporary cover crop or an application of mulch to areas to remain unseeded greater than one month. Disturbed areas which have topsoil removed may require an application of fertilizer prior to temporary seeding. 9. Inspect, clean and repair all erosion control measures the following work day after each storm event. 10. Additional erosion control construction details and specifications shall be taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards. Mr. Basil Hamden Stormwater Utility City of Fort Collins PO Box 580 Fort Collins, Colorado 80522 Dear Basil, Attached is the cost estimate for erosion control measures associated with the construction of a duplex (unit "B") at 629 South Meldrum Street. Silt Fence -180 If @ $2.50 /If Alternate; Seeding -.237 ac @ $1300/ac Security required = $450.00 x 1.5 = However, city policy requires a minimum escrow of ... $450.00 $308 .10 $675.00 $1000,00 Basil, please feel free to call with any questions, comments or suggestions you may have. Very Truly Yours. Joseph P. Marcisofsky, P.E. Structured Engineering LEGEND GRAPHIC SCALE 20 0 10 20 40 eo 0 DESIGN POINT @ BASIN DESIGNATION AREA (ACRES) = GAS METER C"Q., = POWER POLE 1'\ = STUMP = CABLE BOX 0 = CATCH BASIN 5001.5 C8J = ELECTRIC TRANSFORMER I ,-------I I • ( IN FEET ) 1 inch = 20 ft. = ELECTRIC VAULT NOTE: THERE SHALL BE NO DISTURBANCE = ELECTRIC BOX TO NEIGHBORING AREAS FINAL GRADING TO '-" = BRACE POLE . i '6 4999.1 I O _ CLOTHES LINE PIPES ENSURE SITE RUNOFF DOES NOT O 0 5001.5 ~~\5 fR\ = STORM DRAIN MANHOLE ENCROACH ON ADJACENT PROPERTIES. o\~o. r5000-L 149996 ___ 1 5002.3 I poo1.5 15001.1 ~ \W -, "' . \ 7 · ,,_-: 1, 5001·6 I 15001.6 ,,,. ~<::§:) ¢ = LIGHT ,. 36" DECIDUOUS TREE-\ '-1 .. sd,o.1 \ I ~--~~ 5001.7 I 5~.2 DECIDUOUS TRE 5000 \ . 1 \ I I ____ :-. I I / ---/--. '-., . ~-'+ \ I ; \ ~ I / I : , 52()1,2 · · · '\. ·. \ ) oodl 1·8 :' 100 LF EROSION . ' • ·_•4 . .. . ~ . . I . 5 1· 1 I I l / CONTROL FENCE \ ~ · 4 . \ d , I (INSIDE EXIST. FENCE AT P.L.) \. .'-. • · '\. 625 \ I' -I I C NC. DRAIN ~AN I 5001.5 SEE DETAIL SHT. 2 \ '." •. · • . ,. "-. MELDRUM \ ·49,9.9 I EOG~ OF PAVEMENT I _!001.6 · 5000·6 '•. '\... · · ... · ·.~001·3 '1-..,~.1.0 0 I . 8" 0 S TREE ' 'x500H · . '\. ~'c>v'f · : r. EXIST. sPoT ELE. (TYP.) 1 DEciou u °' .:<~; .. . ~ .. , •·· ~-.. ~ ,4~ , ... _ .. 1 \ 11 -sooo.1 -.· ·,_j_J,1soo1.o , , . · -. I. · f ·j 11 I . ' -, --\1 ,• r • . . "--~~,:...,.....:,..,,.;-..rr 7 ' \ I I I .. ·"-/ ~' ·,1 1v·;,-~~2 "-"' .. /1 · ,r---1· I " I I I I 3 DECIDUOUS TREE ' -------._,_ / .__:::-··-' ' ~~-.'...-·'/<,... .i ~...::::::.:-DRAINAGE BASiNS ~ .·· .:r-~~ / / ,,... . ·1 ~£1.r,-9 I / [ -.............. 9" DECIDUOUS TREE /-------~ ·r:-::--:::. . r.z---~; "' • > '. Vsooo I .. \ ~ ·I / . ~ CHAIN LINK rd• -------· :) -:::,-:._.. . ?.-fl. / i\_'-·~-STUDY AREA '\. .:._----4 • .f-/ / / J 5abo.2;~ . I ~--· ·• 001.5 ,-.. ..-, .--.r-... --;-. ,~-,-... .,~. s~;r::[~-:::::-=· '._ r\-....' \' ""'--"-• ~t:7:~~~ 1 B-~ .• I \ I I -. --------""'"5~4""''!"--~-:-~-~.,~..----------~ .----7-~-t•2o------7 . q -O · ' 0 c:.':. . _ . 'r: ;,_ ·•:\5001.4 .1--_ 5000.'!\ 4999.9 I 111/V\1 5 ,;---,5001.1 c• ✓ -~-C 5001 0 ·, ,, ? 500i-.-2-----11,./ , ,,, I. \ 1 15001.5 -----===""""~ ---~ .... -. .. ) · ,,-;,i -..... • ~r5001·/·r-------------\ ,11,i,i'sooo.i> I .·1 \I 1 .no "?'--:,..,s'· r o EXISTING ONE ,· ~ ·, '', '\ \ i i i , , \ 5002.5 1 I I I ~~ ;:-,J M"""""~ ...... --.. 1 · soo1.3 _. STORY FRAME _:.....~ol.6~ · ,,. 1 r1'-.. · 5000 8 _J I ~ I I I ~~iy I / -<\ ........_ __ ) HOUSE · 500~z27,'c-~ \ -l~-H:; ~~r.-_-.. . ._5ep<>·3 / I I ~ i-------~ \ ) 18" DECIDUOUS TREE ~-.. bc-15~\--+-5000--,.--• · .. 7 sopq.4 / I / -< . ['V ~1-\ ,,. ., 1 5000.3 .' I 11 " (PROPOSED DUPLEX ~---"!f.-,..:c: -1--,~ I \ '1 A. \ 14• -1 ; " 1-----+--1 -.," , ■ <::: _~, ~ ooo ·woOO. FENCE I' : , I [II -629 ~ELDRUM ~,,.,,,, 1 -.... -;. ffi5 \ '-I·· I ; I I !UNIT Bl 5001·2 · -;,1 (~-~, ~r----------,1· . 1/ .· r-w w 0:::: r-(/) ~ I I~ I / MIN. T.O.C.= 03.00 '\J/,1$1Jl\J,':--... t_200~.5-:----~~1.6...,.. ~-,·->//:', \ \ o . 5000.9 '1)l l ~II/ -----t---i ~ I I . soo1.3 ~-rsoo1T - ----6--~~ .a \ \ I-I t r l , ~ _ I y;·--.--z1>-...:::.--' ~ \ .• lu ,). · 5 1.4 j 41 --/-\'"'-"' \ 500'.6 , ... , \ ~ ,CJ' -----~ ___ ..,. : ~-7 -5001.3 · 5001.4 :,,-:1\'· \ \ ~ L ---~ kf1 ~ ~efs'~ ____ 02 5001.1 soor.3--~ 3 12" DEc1ouous TREE \ \ 1:-~~ · 5 o.4 =:) ________ ..,/.,_,_002. IJ1 ~~lyl / -0-= E.: =...o -. 5001· ~ -~ll . . . -,999.8 1-~I~ 5001.1 . . \ •'\ -. ;. •: 5000J! . ~-. · 0:::: ~ 1.4 . 5001.7 \ . 4 '\ . . ·. . " . \ . ~ 0 ---0 I . 5001.2 5001.5 001.3 ----- ---~.O.P~ - _. 5001~ --------~CON<:_ ORA~ ~A~~ •5001.~ \·• . ·,. \ ~•~ . -~ . .,I _j -------~----==r.!2------7--:----. . . . ,-~ .. ..;..1 ....... -· ------"---'--~ .... \. • , .... ,l·1 4 • _..-1.. ~~-=-,4,..;.--- -------- -----· --;-/\1\-1 ---------ld5001.6\· · , • . W _J ---------· ;:,vul.4 · "7<N .5 '\' ·. \ ·' . 5001.4 -sgga .... ____ --~ _______________ -_ --~ _____ -__ -__ -...._ -r-~~~-----_ ~ ~~ _ ----~ ----RIM = 5001.13 . 5001.1 \ • · \,. i . " 4· ,. ~ 5001 8 «/V\17 · 5001.7 ------ ---·.5001-.5 ·'. -.• .. ·. .41 5001.6 5001.7 RIM = 5001.8 • . vVV ._,..__ ----. 5001.6 ,. --_.,_ \5001.~--sooo.o ·. 4 ... \ \ 12" INV. E. & N. = 5000.01 6" INV. S. = 4999.91 629 SOUTH MELDRUM 5001.1 UNDERGROUND l,_2 \ '_~ IRRIGATION DITCH5001.4 5001.4 I r-=:) 0 (/) .,, .,, .,, ......... ......... ......... ::c::c::c .,,.,,.,, 000 inoo -N _N., .,.,., ---NNN NNN l SC...\rl--Ai'l. SI"""'-v'\o 1 ~f r o v ~Nt e..~½ Cl/"~ Q D<e J ::. a_ µ 's -r . ~sJe. C:; S½fg--(~. 1 ss . -0/(, ;;--✓ f?As \t-.l (!) D (:).J~ • J . /rrL--. 10 '1:> ?O 'Sf -\0"2..o sr- (pCJ o Sr- 17-z.o SP- 2.e,r, Sr- \~ 't>o Si:- ~ le $,~ '=,4'8 ~ t=- - C (k IM-e..... l "'-~ C ~-.!>.S. = 4 ,o O s ,;:. .. l 0 Cai.,v...f...,.~\\-<L c_,,, 538 ~(,,s\-. G.'t6'(s')-r 4,oo(.\) .-=-.1=>1 ~ f,r o """'-' o-.. bcJ v e ,,I A-c'J.&: Ci-1)t flc,..tt.vor\c.. ('lo l- 0.c.c.ou,.,k.t: for ~bo"c.. NJ~ 61-1s+-Cv-✓""~ ( 1b ~ ~ MCPc.0) ~\ "&,,.-_ ~.A-o--~ ':> 3/ ''"'"" ......... 111111111 111111111 :z::z::z: .,,.,,.,, 4-.. 000 lftOO /Jt.Lc<{ -N @ _N.,, .,,.,,.,, ---NNN NNN @I) C1Jer~,~ \01Yh-- -c(o tl,l,{,-: ,?5qg :_ , 51, 1sooc::> ' ff.5 4. l 1S'E>O 5~ I a_ 'Z,.O (ooO Z1 Ge, G.S-4, -\bSc:, (p 4 '2:, "' <.. s \- 629 SOUTH MELDRUM STRUCTURED ENGINEERING PROJECT N 9603 HYDROLOGIC CALCULATION WORKSHEET BY: JPM RATIONAL METHOD PROCEDURE DATE: 16-Feb-96 BASIN DATA 11 INITIAUOVERLAND TIME TRAVEL TIME 11 TOTAL 11 Ti Tt II TIME II BASIN II DESIGN II ATIONA II EVENT AREA LENGT SLOPE Tc LENGT SLOPE VELOCITY II Tt II Tc II ESIGNATIO II STORM II COEFF II COEFF II II II C II Cf acres ft % min ft % fps II min II min [ENTER] II [ENTER] 11 [ENTER] 11 [ENTER] [ENTER] [ENTER] [ENTER] [ENTER] [ENTER] [ENTER] II H-1 I 2 yr I o.57 I 1.00 0.110 65 3.8 10.0 II 0.0 10.0 H-1 I 100 yr I o.57 I 1.25 0.110 65 3.8 10.0 0.0 10.0 D-1 I 2 yr I o.57 I 1.00 0.110 65 3.8 10.0 0.0 10.0 D-1 I 100 yr I o.57 I 1.25 0.110 65 3.8 10.0 0.0 10.0 H-2 I 2 yr I 0.44 I 1.00 0.237 185 0.5 21.1 0.0 21.1 H-2 I 100 yr I 0.44 I 1.25 0.237 185 0.5 17.6 0.0 17.6 D-2 I 2 yr I o.57 I 1.00 0.237 185 0.5 16.9 0.0 16.9 D-2 I 100 yr I o.57 I 1.25 0.237 185 0.5 12.4 0.0 12.4 RUNOFF SUMMARY 629 SOUTH MELDRUM NOTE: MINIMUM VALUE OF Tc IS 10.0 MINUTES BASIN DESIGN DESIGN DIRECT RUNOFF POINT STORM Tc AREA COEFF RODUC Q mins acres C*Cf C*Cf*A in/hr cfs H-1 1 2 yr 10.0 0.110 0.57 0.06 2.50 0.16 H-1 1 100 yr 10.0 0.110 0.71 0.08 7.20 0.56 D-1 1 2 yr 10.0 0.110 0.57 0.06 2.50 0.16 D-1 1 100 yr 10.0 0.110 0.71 0.08 7.20 0.56 H-2 2 2 yr 21 .1 0.237 0.44 0.10 1.80 0.19 H-2 2 100 yr 17.6 0.237 0.55 0.13 5.60 0.73 D-2 2 2 yr 16.9 0.237 0.57 0.14 2.00 0.27 D-2 2 100 yr 12.4 0.237 0.71 0.17 6.50 1.10 ( RAINFALL PERFORMANCE STANDARD EVALUATION ---------------------------------------------------------------------1 PROJECT: ~ 2.~ :;,, H.EL Q f2-'-' "'--lJ 0-t 1-(3 STANDARD FORM A I . I COMPLETED BY: J f vV' DATE: z/i .::.. / ~ I# ! !---------------------------------------------------------------------1 DEVELOPEDIEROOIBILITYI Asb I Lsb I Ssb I Lb Sb I PS I SUBBASIN I ZONE I (ac) I (ft) I (i) . I (feet) (%) I (~) I ---------1------------------1-------1-------1--------------1-------1 I I I I 1° c < I 7\ 0 I I D --z.._ ~ e ~~ .7-~ 1 I I ! 0 .) · • '? I 1 0 I I I I 1 I I I I I I I I I I I I I I I I I 1· I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I i I I I I I I I I I I I I I 1---------------------------------------------------------------------I HOI/SF-A:1989 EFFECTIVENESS CALCULATIONS 1----------------------------------------------------------------------! I PROJECT: c'.:.zs .S o url. \Me.l&v..iv~ -U V\\t 5 STANDARD FORM B I I / . I I COMPLETED BY: ~ (' 0-,\ DATE: -Z. 1 "I / 'i l,., I I ___________________ I I I I Erosion Control C-Factor P-Factor I I Method Value Value Comment I f'M~=~-----------------:~~--------~::~----------------------I 6=JT..+f>L1~1-t€: 0 ~I'--+-'.]~ ' 0 8 r.o c.) I 115o t1 5ec_~l o."" t ,, I -~11.Av~I M"l~ • , 7 ,4vc...· l,oc.:> -fA-f.1'11->C, 5'fAl.LS I ----------------------------------------------------------------------, MAJOR PS SUB AREA j BASIN (:) BASIN (Ac) CALCULATIONS ------------------------------------------------------------------ I· I Lu + 'J (_ = , s 2(.0 1) .\-, 3{.oc..) -4-,41.(,0 -?')'= , 6 '-6 Lu rJ. 1 ~ , 5 z... }--p<-~ A-z.. ~ \,oO . E,,'ffC-!..•nve.."'<."\'.:.::: ~-,o"') \OO ' 9.4.. 0 /., I I I I I I I I I I I I I I I I I I I I ----------------------------------------------------------------------1 HDI/SF-8:1989 _j