Loading...
HomeMy WebLinkAboutDrainage Reports - 09/04/2013City of F4. Collin Approv tans Approved By Date _ 1 Addendum to the Final Drainage & Erosion Control Report For Lots 1 & 2, Boardwalk Crossing, Filing 2 I I I I I 11 I i I Located at McClellands / Mail Creek Drainage Basin Fort Collins, Colorado February 20, 2013 Prepared for: George Holter 3509 S Mason St. Ft. Collins, CO 80525 Original Report Prepared by: Stewart & Associates, Inc. 103 South Meldrum Street Fort Collins, CO 80521 Phone: (970) 482-9331 Certified by: Forbes Engineering LLC 2908 Cherly Street Fort Collins, CO 80524 Phone: (970) 232-6014 1 FORBES ENGINEERING 1 Full Service Civil & Structural Engineering February 25, 2013 1 Glen Schlueter City of Fort Collins ' Stormwater Engineering 700 Wood Street ' Fort Collins, CO 80521 RE: Drainage & BMP Certification for site improvements at Boardwalk Crossing at Mason Street 4012 So Mason St, Fort Collins, CO ' Mr. Schlueter, This letter and attached report is to serve as certification of the Addendum to the Final Drainage and Erosion Control Report produced for Lots 1 & 2, Boardwalk Crossing, Filing 2 by Stewart & Associates, Inc., dated April 1, 2005 (a copy of this report is attached with this letter and a copy of the original Final Drainage and Erosion Control Report prepared for Nadine Holter can be produced if required). ' The Boardwalk Crossing site improvement project is located at the Northeast corner of Mason Street and Boardwalk Drive. The improvements to the site include the construction of two commercial buildings along with the required site improvements. The proposed improvements remain the same the previously ' approved project but for the increase of 2,000 square feet to the southwestern office/retail building. This additional building's roof area will be off -set by the . ' decrease in pavement area which has a higher run-off coefficient than the roof so the projected run-off will decrease by a very small amount. ' As with the original report, the storm water quality will be maintained using Best Management Practices as outlined in the report and with construction methods as ' shown on the Utility Construction Plans. All proposed drainage patterns and sub -basins remain the same as the original ' design. A grass island has been designed for the extended detention and all runoff will be directed to the existing 30 inch RCP located within Boardwalk Drive which was constructed for the McClellands/Mail Creek Drainage Basin. I 1 1 1 1 1 I 11 Runoff from this site will be restricted to 0.87 CFS per acre as allowed by the McClelland/Main Creek basin. Storm Drainage facilities required for this development include an extension of the 12 inch ADS pipe, a water quality control structure with a pond outlet restriction plate as well as the extended detention restriction plate and a four foot concrete pan to allow flow from South Mason Street via a curb and sidewalk chase. Adjustment to the original report's City Erosion Control Escrow to match current prices is as follows; Erosion Control Cost Estimate 1. Silt Fence: 2. Gravel Filter: 3. Straw Bale Filter 900 LF @ $3.50/Ft = $3,150 2 @ $200 = $400 1 @ $150 = $150 Total = $3,700 With an uncertainty factor of 1.5, the required City Erosion Control Escrow Amount is $5,550 The conclusion of the storm drainage report & system review for this project is that it was completed in accordance with the criteria set forth in the Larimer County Stormwater Design Standards and the USDCM. The design conforms to the drainage basin design of the Mail Creek Master Plan Update as well as the City of Ft. Collins Design Criteria and Construction standards and that no adverse affects to surrounding properties are anticipated from the proposed improvement of this site. Sincerely, 35265 Forbes, P.E. #35 1 1 1 1 1 1 ADDENDUM TO THE FINAL DRAINAGE AND EROSION CONTROL REPORT FOR LOTS 1 AND 2, BOARDWALK CROSSING, FBJNG 2 LOCATED IN THE MCCLELLANDS / MAIL CREEK DRAINAGE BASIN PREPARED FOR NADINE BOLTER April 19 2005 PREPARED BY STEWART & ASSOCIATES, INC. P.O. BOX 429 103 SOUTH MELDRUM STREET FORT COLLINS, COLORADO 80522 TEL: 970.492.9331 FAX: 970.482.9382 I 1 [1 i 1 1 [1 1 1 1 1 1 1 1 VICINITY MAP SCALE - 1"=2000' MEMO j 1 �Ll1G��✓�/ii/� Nrxwrnwi-ws r.e.r I I i - II�p� (— � nylk�T RC—Y • S_ —�1 uli Yl Tj=_JI •. � YrI..HIJ Awslr x1M1n - uNr r m.t I Mrr re�•M1Fs'FL s. r i �I I R ww�ibe �� B BNee 1 NOBI ... ceeosx xixoe su eBiviziBx --I --- .srr 1 ' STEWA r&ASSOCIATES Cortiwlting Engineers and Surveyors 1 April 1, 2005 ' Mr. Basil Hamden Stormwater Utilities ' City of Fort Collins P.O. Box 580 Fort Collins, CO 80522-0580 ' Re: Boardwalk Crossing at Mason Street ' We are proposing to develop Phase II of Lots 1 and 2, Boardwalk Crossing Filing 2. A bank building along with the parking lots West and also South of the bwlding that we constructed in 1997. This phase will be to construct the South and North buildings and the parking lot between ' them along Mason Street. The buildings and parking lot have been revised to our present need. These changes however are minimal from the original design. ' This addendum is to update the original design calculations and erosion control methods to the City Current Standards. Most design and calculations within this report are m compliance with the City of Fort Coffins Strom Drainage Criteria and Construction Standards. The one design ' exception is the detention pond depth in the parking lot exceeds the City Standard of 12-inch depth by 0.1 to 0.2 feet at the flow line of the curb around the water quality control island in the middle of the parking area We are asking for a variance because this flow line area is not either ' a walking or parking area In fact at the lip of the gutter, which is two feet wide, we meet the City criteria of 12" of depth. This area that exceeds your standard is very small and does not affect health, safety, or welfare of this project. If you have any questions or comments regarding this report, please let me know. ' Sincerely, ' Franklin D. Blake, P.E. & L.S. ' FDB/meh 1 James H. Stewart and Associates, Inc. ' 103 S. Meldrum Street • P.O. Box 429 • Ft. Collins, CO 80522 970/482-9331 • Fax 9701482-9382 ' April 1, 2005 ' ADDENDUM TO THE FINAL DRAINAGE AND EROSION CONTROL REPORT FOR ' LOTS 1 AND 2, BOARDWALK CROSSING FILING 2 EXISTING SITE: ' This site was originally designed in 1996 and the bank building and the parking lots on the West and South sides of the lank constructed in 1997. The developed site was constructed as the ' designed grading, drainage and erosion control plan show on Sheet 4 of 5 of the Approved Utility Plan. That sheet is included herein along with the original drainage report for re&rence. ' All lots and roads around this phase have been constructed. The site is bounded on the North by Boardwalk Avenue on the East by the banks parking lot and REI; on the South by a 30-foot wide access road; and on the West by South Mason Street. ' Runoff from this site will be as originally designed which will be to route an runoff to the Stormwater System in Boardwalk Drive which was constructed for the McClelland / Mail Creek ' basin. Runoff from this site will be restricted to 0.87 c.£s. per acre as allowed by this basin. The S.I.D. fee for this project was paid for at the time of the bank construction. ' DESIGN CRITERIA: The rational method will be used to determine the developed site mitial and major storm nmDfi Detention for the site will be based on the 100-year storm less the allowed release rate of 0.87 c.£s. per acre. The mass diagram will be used to determine the required detention An calculations and design consideration are in accords= with the City of Fort Coffins Design ' Criteria Manual, except the historic 2-year storm will not be used for the release rate. DEVELOPED SITE: ' All proposed drainage patterns and subbasins remain the some as the original design. This phase is in Sub -basins A, D, and part of C. Sulrlasins C and D are existing except for the North proposed balding and cannot be changed with this project. Sub -basin 4 which includes offsire flows from Mason Street will be designed to include the City's new intensity data and extended detention A grass island has been created fin the extended detention. All runoff from this Phase 2 will be to the existing 30 inch R.C.P. storm dmin in Boardwalk Drive which was constructed fDr the McClellands/Mail Creek Drainage Basin. This pipe system outf alls into Mail Creek. Storm Drainage fieitities required far the Phase 2 will be the extension of the 12-inch A.D.S. ' pipe. The water qualify control structure with the pond outlet restriction plate and also the extended detention restriction plate. The four -foot concrete pan to allow flow from South Mason Street and the sidewalk chase. ' EROSION CONTROL: ' 'Phis site is in a moderate to high rainfall erod"ity zone and m moderate to high wind erodrbrlity zone. Rainfall performance standard evaluation and effectiveness calculations were ' completed with the original report and have not changed. The required City Erosion Control Escrow Amount is $2950. ' This phase will construct a silt &nce along the North and South property lines and on the East Property line along the REI site and also along the West line of the wdstmg West parking lot, and along South Maxon Street. A gravel filter shall be placed around the existing area inlet in the said West parking lot and also around the area inlet on the South parking lot of the bank. A straw bale barrier shall be placed around the WQC structure in the grass island LJ 1 1 1 1 1 J I 1 1 1 1 STORM DRAINAGE 1 CALCULATIONS i i 1 1 i 1 1 1 1 1 1 I I I I I 1 1 STEWART&ASSOCIATES PH. S. -9331 FAX FORT COLLINS, C080521 PH. 482-9331 FAX 482-9382 Consulting Engineers and Surveyors �� By: G-/aa�.� / Date: //�O/O�/ CIiiern: Z/'�O/hB 170 145G - Sheet No. / of Project: Z:; ly %o/A G/oSS/�'� 19P Subject: 40 /I e i4a,ld frBS o��d �vai�v '00 DF�e O.G34Va 9w aQ (,/ 7� d/i89ar� d/���G. Bss zLJ 5"�3-C flow To �,t�$ i• �o o' Easf o% -p. A0 goo S; �c Fr G'a/ r/a•0 -1. _ ,� 3� arsres re/ arm D 3G as X 40, 7,?) 0, 95 3y e 0, 2 y8' zOr 7� I I I I I I I I I I I I I 1 I I STEWART&ASSOCIATES Consulting Engineers anti Surveyors By: _/"/ Date: �3�-DS Client: Project: LO7s a1 .s 103S. MELDRUM, FORT COLLINS, CO80521 PH. 482-9331 FAX 482-9382 r Sheet No. ��of / e ah0 G'z a=07x Gam,, aq7- d�C'vr�cAl�i^� o•7 : fi�r�es 3 oe . ";c Z 40,2'.D t 5'72 5' G2 Goaly �`f7?l • �,ir� Op ' Z/rlin f ,�D,r/..y S = yoo �jon ; 8.55 Quo • D, 7X x 41.4Wx O.G3 = % 97 :ifs �� = 0,97 x. jO55 x D, G 3 = 5: 72 Cfs I No Text 1 1 1 7 1 . DRAINAGE CRITERIA MANUAL 5C 1 F 20 z w c) W a 10 z W n O 5 H w cU)c 3 O U 2 IX Q 3 1 .5 /-C RUNOFF FA� � -........I..♦.5�.............� VELOCITY• • 20 FIGURE 3-2. ESTIMATE OF AVERAGE FLOW VELOCITY FOR USE WITH THE RATIONAL FORMULA. *MOST FREQUENTLY OCCURRING 'UNDEVELOPED" LAND SURFACES IN THE DENVER REGION. REFERENCE: -Urban Hydrology For Small Watersheds" Technical Release No. 55, USDA, SCS Jan. 197S. ' 5 -1-84 URBAN DRAINAGE d FLOOD CONTROL DISTRICT T 1 1 [J City of Fort Collins Rainfall Intensity -Duration -Frequency Table for using the Rational Method (5 minutes - 30 minutes) Figure 3-1a Duration (minutes) 2-year Intensity in/hr 10-year Intensity in/hr 100-year Intensity in/hr 5.00 2.85 4.87 9.95 6.00 2.67 4.56 9.31 7.00 2.52 4.31 8.80 8.00 2.40 4.10 8.38 9.00 2.30 3.93 8.03 10.00 2.21 3.78 7.72 11.00 2.13 3.63 7.42 12.00 2.05 3.56 7.16 13.00 1.98 3.39 6.92 14.00 1.92 3.29 6.71 15.00 1.87 3.19 6.52 16.00 1.81 3.08 6.30 17.00 1.75 2.99 6.10 18.00 1.70 2.90 5.92 19.00 1.65 2.82 5.75 20.00 1.61 2.74 5.60 21.00 1.56 2.67 5.46 22.00 1.53 2.61 5.32 23.00 1.49 2.55 5.20 24.00 1.46 2.49 5.09 25.00 1.43 2.44 4.98 26.00 1.40 2.39 4.87 27.00 1.37 2.34 4.78 28.00 1.34 2.29 4.69 29.00 1.32 2.25 4.60 30.00 1.30 2.21 4.52 I /C i 1 Project = Inlet10 = 1 U 1 1 i 1 1 i i 1 1 1 1 1 i wP Lu wP H Gutter Yd Pan water Flaw Direction in Information pnptM h of a Unit Inlet LP = 4.00 It Depression, if any (not part of upstream Composite Gutter) 81.w = 2.00 inches it of Curb Opening in Inches H = 6.00 inches Nldth for Depression Pan WP = 3.00 ft Ong Factor for a Single Unit (typical value = 0.1) C. = 0.10 of Throat (see USDCM Figure ST-6) Theta = 83.4 degrees e Coefficient (see USDCM Table ST-7) Ca = 0.67 Coefficient (see USDCM Table ST-7) Cw = 2.30 Number of Units in the Curb Opening Inlet No = 1 "I,r!r sign Discharge on the Street (from Street Hy) Q, a 5.2 cfa der Depth for the Design Condition Ye = 5.81 Inches al Length of Curb Opening Inlet L = 4.00 ft pacify as a Weir without Clogging Q 1= 7.3 cfa gging Coefficient for Multiple Units Coef = 1.00 egging Factor for Mu Nple Units Clog = 0.10 pacify as a Weir with Clogging 0.. = 7.0 cis an orrnce p=4 as an Orifice without Clogging Qa = 5.5 uds pally as an Orifice with Clogging Q. = 4.9 cfe aaclty for Deslan YAfh Cloaalno Q.. 4.9 aft pture Percentage for this Inlet a 0, / Q, C% a 64.68 % Note: Unless additional ponding depth or spi fmg over the curb is acceptable, a capture percentage of less then 100% in a sump may Indicate the need for additional inlet units. 1 UD-Inlet v1.06a-*, Curb-S 2110/2005, 10:43 AM I I I I I I I I STEWART&ASSOCIATES 103 S. MELDRUM, FORT COLLINS, CO 80521 Consulting Engineers and Surveyors PH. 482-9331 FAX 482-9382 By /aafi Date:,&--`� Client: O� / _ Sheet Nn %nf Project: Subject: �`-v,��asi� dF-. / F � �J G"v�cey�� �i'o.� �i•� � a. �� � � _ ac'� 70 Cac - ©. 97 = z y s/; --,ov/ , = 3pr' Q= c-�Z' 0,0- �z= e,7? 9s zoo 11 3 k 1 1 1 0 I Z 00 0 W W 1 F— LLJ � � F LL W O �R p U' Z W W CC W _W U) c w c � 11 Q W O ic K p �It7 U COCl) l I,. co lC II. in f��Qj OOQjDO^MO �KOQ NO II 000000000yy0000bc000CD, °Nc�5., 00a 0 kj NIOMhMaor--� 00LQ .� T f��j �eeep��f SLL D fT CC)O+-�N T T T T C-0 T T T 099O�� T T T T T T T T T I A R A M ��pp co cp cp cp m R M Mp U suG:: W Im Y! fO ui Ni a co to 6 CQ cm cq TTTTT a 000o0o0000000?00000000 LU L. T T T T T T 1 1 1 1 1 H Z m W cc c D Z W OIr ZO LW I— r Z WW 0 w 0 cc O CY LL W Mr W �crR t V V/ Q v/ @Q C L2 r ti N Womou IEEE DRUID 3o SCOOOT R o gog � 8 0 e peg a o ` �y 7 s e �dd �LLy it "y m F o W 0 ro m � R nOa{ er e ui o �r 0 Z 1 103 S. MELDRUM, FORT COLLINS, CO 80521 $TEWART$,�SSOCIATE$ PH. 482-9331 FAX 482-9382 1 Consulting Engineers and Surveyors By: Jae'.17 Date: Client: /'7dlx/ Sheet No. 15- of 1 Project:_ 2612/,� Subject: 1 D 9-1 70 cz o, 78 -7773 fe A".5,'GWa14 1 _ 1 Vr9 109. .9.p�J.of 1 y 3 j1rra��ow-D:D7ir� Z n, DETENTION POND HIGH WATER LINE EXTENDED DETENTION --dO-NTOUR L;tjmmL# AREA AVERAGE AREA INTERVAL HIGH WATER ft JL VOLUME (cuft) VOLUME cu,ft LINE ft 32.1 0.0 Xx� 33.0 200.0 34.0 "8.0 >- 34.8 35.0 4,092.01 36.0 . . . . . . . . . . . . Mffl-,lvt P 3.. .. . m, 36.1 17,200.0 .Yu L NOTES: 1. FOR THE FIRST CONTOUR VOLUME A CONIC SHAPE WAS ASSUMED VOL. = 1/3 (AREA ABOVE) (DIFFERENCE IN COUNTOUR ELEV.) 2. FOR THE REMAJMDER OF THE VOLUMES BETWEEN CONTOURS (SECTION 9.2) VOL. = DEPTH/3 (A +(AB) -.s + B) FOR: Uniform Sides sec. (9.2) 3. HWL=(VOL.REQ.-VOL-LOW CUML)*3/(AREA LOW+AREA HIGH+ (low area*hIgh area) ^.5) R U %to _W001fifflo.5?l 7 I p [] C I I I DETENTION POND HIGH WATER LINE INCLUDES EXTENDED DETENTION VOL. = 1/3 (AREA ABOVE) (DIFFERENCE IN COUNTOUR ELEV.) 2. FOR THE REMAIMDER OF THE VOLUMES BETWEEN CONTOURS (SECTION 9.2) VOL. = DEPTH/3 (A +(AB)-.5 + B) FOR: Uniform Sides sec.(9.2) 3. HWL=(VOL.REO.—VOL.LOW CUML)*3/(AREA LOW+AREA HIGH+Vow area*high area) ^.5) ORIFICE SIZING ORIAINAI nFRIrN nATA 1.21 — Allowable Des. Release Rate cfs 32.11 = Flowline Orifice Elevation 0.65 = Orifice Coeifldemc 3.87 = Available Driving Head 11 VERT. SQUARE PLATE NOTE:1. VERT. PLATES WILL BE PLACED AT PIPE FLOWLINE I 00 EMERGENCY SPILLWAY DESIGN Weir Equation Q = C L (H) -3/2 Q (cfs), C (weir coefficient), L (crest length, feet), H (energy head, feet) 22 = Weir Length L in feet 3.1 = Weir Coefficient Weir Shape Broadcrested Design Flow 13.53 (cfs) Depth of flow ft Flow Over Weir cfs 0.10 2.16 0.15 3.96 0.16 4.36 0.17 4.78 0.18 5.21 0.19 5.65 0.20 6.10 0.30 11.21 0.40 17.25 0.50 24.11 y D- 35 -S 4 S 6 7 8 8 10 47 DRAINAGE CRITERIA MANUAL RUNOFF /D Q' 31 1- 2 ( z W U OC W 1C z w I1 0 5 In W ¢ 3 O U 2 K W F 1 .5 VELOCITY IN FEET PER SECOND FIGURE 3-2. ESTIMATE OF AVERAGE FLOW VELOCITY FOR USE WITH THE RATIONAL FORMULA. *MOST FREQUENTLY OCCURRING"UNDEVELOPED" LAND SURFACES IN THE DENVER REGION. REFERENCE: "Urban Hydrology For Small Watersheds" Technical Release No. 55, USDA, SCS Jan. 1975. 5 -1-84 URBAN DRAINAGE & FLOOD CONTROL DISTRICT 1 1 IT 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 City of Fort Collins Rainfall Intensity -Duration -Frequency Table for using the Rational Method (5 minutes — 30 minutes) Figure 3-1a I 1 1 . 1 1 DRAINAGE CRITERIA MANUAL N. 3) 9&10992 UDFp STORMWATER QUALITY MANAGEMENT ,o,77;� Note: Wamrshed inches of ruro9 chap appl.. = watershed tributary to the BMP Faa .. FIGURE 5-1. WATER QUALITY CAPTURE VOLUME (WQCV) 1 1 1 1 . DRAINAGE CRITERIA MANUAL (V. 3) 0.6( mo.0 E 0.2( 0.10 3 Q 0.06 0.04 STRUCTURAL BMPS MIME NUNNE EXAMPLE: DWQ.4.5ft SOLUTION: Required Arearr ■ 91-OA Oil 0.01 1.0 2.0 4.0 6.0 Requked Area per Raw Qn.2 ) Source. DmVAw Camry Sbnn Drainage and Teduiieal CrRerIa.1966 FIGURE 5-3. WATER QUALITY OUTLET SIZING: DRY EXTENDED DETENTION BASIN WITH A 40-HOUR DRAIN TIME OF THE CAPTURE VOLUME 13 DRAINAGE CRITERIA MANUAL W. 3) STRUCTURALSMPs A Threaded WaterOuality Capplure Volume Level (includtn 20% additional volume for sediment storage) Gravel (1-12'to 3' Rods) Around Perforated Riser Filter Fabric Water Quality Riser Pipe (See Detail) Notes: 1- The outlet pipe stall be sized to control overflow Into the concrete riser. 2. Altomate designs Include a Hydrobrake outlet (or odfce designs) as long as the hydraulic Performance matdws tlds conflgraatlon. Notes:1. MOnimum number of holes . 8 2. Minimum hole diameter. le dia. 1-12' 1 Vent in Ductile Iron or Steel Pipe (Min. 3 ft) OUTLET WORKS NOT TO SCALE WATER QUALITY RISER PIPE NO SCAL Removable & Lockable Overflow Grate for Larger Storms Outlet Pipe — Size Base to Prevent Hydrostatic Uplift FIGURE 5.2. WATER QUALITY OUTLET FOR A DRY e-1-1992 EXTENDED DETENTION BASIN UOFCD `+B •G3 tl STEWART$,,SSOCIATES 103 S. MELDRUM, FORT COLLINS, CO 80521 Consulting Engineers and Surveyors PH. 482-9331 FAX 482-9382/� BY: �Gh Date: / Client: /YO� i Sheet No. 1'of Project: O: vaAW9/� < 2DD .