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Drainage Reports - 09/26/2012
G' F September 25, 2012 Mr. Wes Lamarque City of Fort Collins Stormwater Utility, 700 Wood Street Fort Collins, CO 80522 INTERWEST.- C O N S U L T I N G G R O U P City of Ft. .,.Collins Approved Plans Approved 'S s 1.4 Date q-.L6-1,L Re: Elizabeth & City Park Corner Redevelopment — Storm Drainage Report Dear Wes, We are pleased to submit for your review and approval this drainage letter showing the drainage impacts from the proposed redevelopment at the corner of Elizabeth Street and City Park Ave. The project is located at 1401 West Elizabeth Street and is platted as Lot 2 of Eleventh Fairview Subdivision. The site currently has an existing Mexican Restaurant (Consuelo's) and. an asphalt parking lot on the site. The project will demolish the existing building and parking lot. In its place a new commercial/mixed use building -and parking lot will be constructed. The proposed improvements will reduce the impervious area by approximately 5% and will provide for stormwater quality on site. The area of the site that will be improved is approximately 0.52 acres. The site is just west of the Colorado State University campus and is bounded on the north by West Elizabeth Street and bounded on the east by City Park Avenue. There is approximately 0.12 acres of offsite area just south of the proposed lot that is tributary to the site. Today, the entire site sheet flows to the east and northeast where it is intercepted by either City Park Ave or W. Elizabeth Street.. Flow continues east along W. Elizabeth Street until it is intercepted by a Type R inlet where it enters the city storm sewer along W. Elizabeth Street. With the building addition and reconfiguration, the majority of water in the parking lot will sheet flow to the east to a pervious landscape detention area (rain garden). Water will then be piped north to the existing city storm system in W. Elizabeth Street. All roof water will be piped directly to a new 12-inch storm system that connects to the existing city storm system in W. Elizabeth Street. The site is required to provide water quality treatment. A pervious landscape detention system (rain garden) is proposed to achieve water quality treatment for this site. Because of the grades of the site, we are unable to drain all of the onsite water to the proposed rain garden. The onsite parking lot, in addition to 3,050 sf of the offsite parking lot to the south, will be conveyed to the rain garden. Due to site constraints, roof runoff and a portion of the sidewalks around the 1218 W. ASH, STE. C, WINDSOR, COLORADO 80550 TEL. 970.674.3300 - FAX 970.674.3303 Mr. Wes Lamarque ' September 25, 2012 Page 2 of 5 ' building will not be conveyed to the rain garden. The rain garden will be 12-inch deep and filled with a granular material following the guidelines in Urban Drainage. Once the rain garden is completely saturated, water will be conveyed to the new 12-inch storm system by two 4-inch ' perforated pipes at the bottom of the rain garden. The water will then be conveyed north to the existing storm sewer in W. Elizabeth Street via a new 12-inch storm system. During large events water will overtop the curb surrounding the rain garden and follow the original flow path north ,. along City Park Ave to W. Elizabeth Street. The existing and proposed imperviousness of the lot was compared as a part of this study. ' Exhibits are attached which show that the existing imperviousness is 96% while the proposed improvements will lower the imperviousness to 91 %. This is due to an increased offset from the ' eastern property line to the building as well as a small landscape strip along the northern property line between the building and the sidewalk on W. Elizabeth Street. Because the impervious area will decrease with this project, detention is not required. Attached is a summary of the flows for ' the existing and the proposed site. With the reduction of. impervious area by.5%, the 10-year flow off the site is reduced by 4%. However the 100-year flow off the site remains the same. ' The proposed private 12-inch PVC storm system and 6-inch roof drain system are the only two hydraulic system on the project. The 6-inch line extends on the south side of the building and will pick up two small area drains on the east side of the building as well as two roof drains. The ' roof drain system consists. of two 6-inch pipes with an overflow 2 inches above. the opening. Each pipe has a capacity of 0.42 cfs before the water spills through the overflow. The roof drain system will convey 93% of the 10-yr storm (roof, drain capacity, = 0.84 cfs, 10-yr flow = 0.9 cfs). Any event greater than the 10-yr storm will spill off the roof and sheet flow to the parking lot south of the building and ultimately end up in the proposed "rain garden. The 6-inch line tees into the proposed 12-inch system. The 12-inch system collects runoff from the rain garden and the 6- inch system and it will be connected to the existing 24-inch main line in W. Elizabeth Street via a new manhole. Our calculations show, a 10-year flow to the proposed 12-inchsystem of 2.5 cfs and a 100-year flow of 5.6 cfs.. We have verified that the system can convey the 10-year flow. ' 100-year flows that cannot be conveyed underground will overtop and. flow into City Park Ave where it is conveyed north to W. Elizabeth Street. All overtopping occurs below the proposed finished floor. ' Following the Urban Drainage design procedure for sizing rain gardens, the required water quality capture volume for the proposed. site is 750 cubic feet (including the roof area and ' sidewalk area that is unable to be conveyed to the rain garden). The proposed rain garden provides 420 cubic feet of volume, which is approximately 56% of the required water quality capture volume. Due to existing grades, a small portion (5,163 SF) of offsite runoff is conveyed to the proposed rain garden. If you take the onsite area that drains to the rain garden combined with the offsite area. and exclude the. onsite area that cannot be conveyed to the rain garden, the required water quality capture volume is 539 cubic feet. The proposed rain garden provides 420 ' cubic feet of volume (78% of the required volume). We have maximized the area of the rain garden with the existing constraints that are associated with the site. Please see the attached Urban Drainage Design Procedure form for more information. ' 1218 W. ASH, STE. C, WINDSOR, COLORADO 80550 TEL. 970.674.3300 - FAX 970.674.3303 Mr. Wes Lamarque ' September 25, 2012 Page 3 of 5 ' With the redevelopment of the site, the design team has followed the four step low impact development process outlined in Urban Drainage. With the decrease in impervious area we have reduced the runoff from the site during small storms and there is no increase in runoff during the 100-year event. A rain garden has been incorporated into the design to treat and slowly release 100% of the water quality capture volume. When runoff leaves the site it is conveyed to a public storm sewer system so there are no streams or channels associated with the project to stabilize. ' An erosion control plan will be implemented during construction that will address source control and unwanted materials (hazardous materials, sediment) from entering the downstream storm ' systems. The contractor will be responsible for implementing the erosion control plan and adequately addressing any spills or clean up on site. 1 All possible. measures Have been taken to provide water quality for the site through the proposed rain garden. The proposed' redevelopment has improved upon the existing conditions by reducing the overall impervious area as well as providing water quality. The site has been designed with provisions for safe and efficient control of stormwater runoff in a manner that will not adversely affect the downstream storm system and will improve water quality for a lot that had no existing water quality system. Overall, it is evident that the proposed. redevelopment will have a positive impact on the overall stormwater management system. FLOODPLAIN INFORMATION: The base floodplain elevations, cross sections and boundaries used on the plans are not from the City's currently effective floodplain model. All floodplain information is from Ayers and Associates DRAFT "As -built. Floodplain Modeling Report Canal Importation Ponds and Outfall Project (CIPO)", dated 2012. A waiver was requested because the City's current effective floodplain model has a higher floodplain but it is based on an old model: Interwest requested to use the more recent model by Ayers which is anticipated to be adopted by the City in the future. The waiver request was approved by the City on September 24, 2012. The adjacent Elizabeth Street ROW is located in a City regulatory 100-year flood fringe and floodway in the Canal Importation Floodplain. The proposed building will be a commercial mixed use building and the foundation will be slab -on -grade. The structure is located outside of the floodway (the floodway is contained in W. Elizabeth Street) and the 100-yr floodplain. The base flood elevation based on City modeling for the site is 5033.1 (NGVD 29). The building is not in the floodplain: A Floodplain Use Permit is required only for the sidewalk and curb reconstruction on Elizabeth. Street. The waiver and permit are attached. 1218 W. ASH, STE. C, WINDSOR, COLORADO 80550. TEL. 970.674.3300 - FAX 970.674.3303 u Mr. Wes Lamarque September 25, 2012 Page 4 of 5 DRAINAGE SYSTEM MAINTENANCE STANDARD OPERATING. PROCEDURE: Records shall be kept regarding perpetual maintenance activities. The records shall show when and which facilities have been inspected and cleaned. Spill and illegal dumping incidents and responses to both incidents shall also be documented and tracked. Rain Garden Inspect the infiltrating surface at least twice annually following precipitation events to determine if the bioretention area is providing acceptable infiltration.. If standing water persists for more than 24 hours after runoff has ceased, clogging should be further investigated and remedied. Additionally, check for erosion and repair as necessary. Remove debris and litter from the infiltrating surface to minimize clogging of media. Remove debris and litter from the overflow structure. ' Maintain healthy, weed -free vegetation. ' If ponded water is observed in a bioretention cell more than 24 hours after the end of a runoff event, check underdrain outfall location and clean -outs for blockages. If clogging is primarily related to sediment accumulation of the filter surface, remove excess accumulated sediment and ' scarify the surface of the filter with a rake. If the clogging is due to migration of sediments deeper into the pore spaces of the media, remove and replace all or a portion of the media. Full media removal and replacement is anticipated every 5-10 years. Storm Drain System Inspect.and clean as needed ADS drain basins, roof drains, clean -outs and the sidewalk chase at least once a year. Remove as much debris, silt, trash and sediment as possible from the storm drain system when. ' cleaning. Prevent material from washing into adjacent storm sewers, streams or channels. 1218 W. ASH, STE. C, WINDSOR, COLORADO 80550 TEL. 970.674.3300 - FAX 970.674.3303 ' Mr. Wes Lamarque September 25, 2012 Page 5 of 5 ' We. appreciate your time and consideration in reviewing this submittal. If you have any questions or need additional information please feel free to call at any time (970) 674-3300 Ext. 102. Sincerely, �.... t v, 288 ra? 90,E ' Michael Oberlander, P.E. ��AJAL�G Colorado Professional Engineer 34288 Interwest Consulting Group Attachments 1218 W. ASH, STE. C, WINDSOR, COLORADO 80550 TEL. 976.674.3300 - FAX 970.674.3303 1 1 I 11 k ---------------------------------------- ---------- ------- v -,z W W W W W 12W W W W W W. EL/ZABETHSTREET � 5 S Imlzm EEL r� F =---- --L- --� I W L. Lvr f , EtEMAMN I. FAO7V/EW SUB I. I 20 O 40 . SCALE: 1 " = 40' PC 1 0 No 9, .-,gimp I' I I II I II I I II II II l I , II I II I: L. I I I I `p ELIZABETH & CITY PARK CORNER REDEVELOPMENT EXISTING IMPERVIOUS AREA 21,512 SF = 96% u 1 Kul I — — — — — — .— — — — — — — — I: I • � � I_II I — C3 2 l Lor l ®lz 1 6YEvEnrnH FAIRVIEWSUB � I• I � I--- \ i I. •� I I, I � I •. I G 20' 0 40' SCALE: 1" = 40' ELIZABETH & CITY PARK CORNER REDEVELOPMENT PROPOSED IMPERVIOUS AREA 20,440 SF = 91 f o n�« 0 s ' H Wo - - - --- 1 1 20 10 O 20 40 t ! -- ----_-----__ - - SCALE: - CR" swy SECIXAY H � U. W. ELIZABETH STREET RETAINING w ---KIN -- / ---_ -_ -�- Au p® ---- s=51 - y: I I I------ 1 I LOT 7- 1 FA/NVIFW I - FF=5034.50 - 0.070.67 u t. SHOPPING CENTS 0.19 0.95 1- . I I - - z r - A LOT2 - .I \ I 1 - ELEVENM \ 1 . A/RVIEW SUB .. I 1 i .I . i 3 I I I' "•� 1 i 't, i 4 I I 5 7. - - 9. 1 I C . 2 1' CURB CUT .\ _ I M - - - - - - - - I - 0.250.92 Boa\ I I 5034 In I 420 CF RAIN GARDEN\ I P I I / II I I r _ - 0.120.94'; `- \ I I co•�pow. I � I �SOJ6� Lam=-_ p\ // ,.0.�' �»° 1 I 1 ELEVENTH I I f l ] y\ 1 - . FAIRVIEWSUB D. --- ------- Mt, I-- --- T • '1 E J J K O >OrO U Q o N o W a a0v o: o. � Z a W IL U.IrOw u0 =0 w 0 IL N . W NOTES: Z SEE LANDSCAPE PLAN FOR PLANTINGS THROUGHOUT THE SITE. C O . THE RIGHT OF WAY ADJACENT TO THIS PROJECT IS LOCATED IN A CITY OF FORT COLLINS 1 OPYEAR FLOOD FRINGE La ND FLOODWAY IN THE CANAL IMPORTATION FLOODPLAIN AND IS SUBJECT TO THE REQUIREMENTS OF CHAPTER 10 �l OF THE FORT COLLINS MUNICIPAL CODE. Q C i . ALL CONSTRUCTION ACTIVITIES IN THE FLOOPLAIN MUST BE PRECEDED BY AN APPROVED FLOODPLAIN USE PERMIT. y /Q . ALL WORK IN THE. FLOODWAY WILL REQUIRE A NO RISE CERTIFICATION. ,Q = a . STORAGE OF MATERIALS OR EQUIPMENT WILL NOT BE ALLOWED IN THE FLOODWAY. W U) ,�,nn V . BUILDING BENCHMARK IS CITY OF FORT COLLINS BM 1-03 ELEVATION 5046.12 FT-NGVD 29. 4 BUILDING FINISH FLOOR ELEVATION EQUALS 5034.50 FT- NGVD 29. W W W Z f . HIGHEST BASE FLOOD ELEVATION ADJACENT TO. THE SITE IS 5033.1 FT-NGVD 29. NOTE THAT THE BUILDING DOES Q �/ �RN/ OT RESIDE WITHIN THE FLOODPLAIN AND FREEBOARD IS NOT APPLICABLE. Z Yn ALL BASE FLOOD ELEVATIONS (BFES). CROSS SECTIONS. AND BOUNDARIES SHOWN ON THIS PLAN ARE NOT III URRENTLY EFFECTIVE. FLOODPLAIN INFORMATION IS FROM AYRES AND ASSOCIATES DRAFT AS -BUILT FLOODPLAIN O x LL W ODELING REPORT FOR CANAL IMPORTATION PONDS AND OUTFALL PROJECT(CIPO) DATED 2012. A FLOODPLAIN _ �+ WAIVER. ALLOWING THE USE OF THE AS43UILTAYRES FLOODPLAIN INFORMATION FOR THIS ADDRESS. WAS APPROVED y a' I Y THE CITY OF FORT COLLINS ON SEPTEMBER 24, 201 2. - a .F}• O. THE TOP OF FOUNDATION ELEVATION SHOWN IS HIGHER THAN THE MINIMUM ELEVATION REQUIRED FOR z ROTECTION FROM THE 100-YR STORM.. - W YYY... DRAINAGE SUMMARY TABLE DESIGN AREA AREA C 10 C 100 Tc 10 Tc 100 Q 10 Q 100 POINT DESIG. ACRES MIN MIN (CFS) (CFS EXISTING 0.52 0.92 1.00 : 5.0 5.0 2.3 5.1 ' PROPOSED 0.52 0.88 1.00 5.0 5.0 2.2 5.1 1 0.19 0.95 1.00 5.0 5.0 0.9 1.9 1 2 0.25 0.92 1.00 5.0 5.0 1.1 2.5 1 3 0.12 0.94 1.00 5.0 5.0 0.5 1.2 4 0.07 ' 0.67 0.84 5.0 5.0 0.2 0.6 U > G °? J 0. 0 . m N � �O W - CALL UTILITY NOTIFICATION CENTER OF COLORADO N p 0 811 ,> _. CALL 2-BUSINESS DAYS IN ADVANCE N 2 m m - BEFORE YOU DIG. GRADE OR EXCAVATE W - FOR THE MARKING OF UNDERGROUND rn Z ' MEMBER UTEUTIES. yl J J U CITY OF FORT COLLINS, COLORADO O X. m o U UTILITY PLAN APPROVAL APPROVED: - CITY ENGINEER DATE ' CHECKED BY: - WATER & WASTEWATER UnUTY DATE CHECKED BY: - STORMWATER URUTY DATE CHECKED BY: - - _ PARKS G RECREATION DATE PROD. NO. 1156097wo0 CHECKED BY: - TRAFFIC ENGINEER DATE -7 CHECKED BY: " NANRAI RESOURCES DAIS DRAINAGE SUMMARY TABLE DESIGN AREA AREA C 10 C 100 Tc 10 Tc 100 Q 10 Q 100 POINT DESIG. ACRES MIN MIN (CFS) (CFS EXISTING 0.52 0.92 1.00 : 5.0 5.0 2.3 5.1 ' PROPOSED 0.52 0.88 1.00 5.0 5.0 2.2 5.1 1 0.19 0.95 1.00 5.0 5.0 0.9 1.9 1 2 0.25 0.92 1.00 5.0 5.0 1.1 2.5 1 3 0.12 0.94 1.00 5.0 5.0 0.5 1.2 4 0.07 ' 0.67 0.84 5.0 5.0 0.2 0.6 U > G °? J 0. 0 . m N � �O W - CALL UTILITY NOTIFICATION CENTER OF COLORADO N p 0 811 ,> _. CALL 2-BUSINESS DAYS IN ADVANCE N 2 m m - BEFORE YOU DIG. GRADE OR EXCAVATE W - FOR THE MARKING OF UNDERGROUND rn Z ' MEMBER UTEUTIES. yl J J U CITY OF FORT COLLINS, COLORADO O X. m o U UTILITY PLAN APPROVAL APPROVED: - CITY ENGINEER DATE ' CHECKED BY: - WATER & WASTEWATER UnUTY DATE CHECKED BY: - STORMWATER URUTY DATE CHECKED BY: - - _ PARKS G RECREATION DATE PROD. NO. 1156097wo0 CHECKED BY: - TRAFFIC ENGINEER DATE -7 CHECKED BY: " NANRAI RESOURCES DAIS U > G °? J 0. 0 . m N � �O W - CALL UTILITY NOTIFICATION CENTER OF COLORADO N p 0 811 ,> _. CALL 2-BUSINESS DAYS IN ADVANCE N 2 m m - BEFORE YOU DIG. GRADE OR EXCAVATE W - FOR THE MARKING OF UNDERGROUND rn Z ' MEMBER UTEUTIES. yl J J U CITY OF FORT COLLINS, COLORADO O X. m o U UTILITY PLAN APPROVAL APPROVED: - CITY ENGINEER DATE ' CHECKED BY: - WATER & WASTEWATER UnUTY DATE CHECKED BY: - STORMWATER URUTY DATE CHECKED BY: - - _ PARKS G RECREATION DATE PROD. NO. 1156097wo0 CHECKED BY: - TRAFFIC ENGINEER DATE -7 CHECKED BY: " NANRAI RESOURCES DAIS 1 1 1 1 1 1 1 1 i 1 1 1 1 1 cis N U C O N a) Cl) C O �. - C 0 a cC 0 > LL 'ts o U y a N 7 O o � O m C;) O Q c p In In LO to cc- Urnrnrnc\l O 0.000 O U co s; cz »•� O ca U ri p` S c6 U) O co U H E co0) co �. O L as 1 N J N S.: 5 a nuGi� a�' N_0 ui ... w 'r h V•1 U V) d m o U �. CD CL O °C o z 0 CD CD c c E E ¢tia o0 0 Ocs;OQ a) aa) as Un CcCC `m m cn E p O J co p o d O J (n -6 O C O Q Co O O c p c W •X O cmco N co ccwa��ao a) O Q 0 G= 0 > o to 0 O uo co 0 y` C1 O W w E LL O LL U Z W N rn m 0 m rn N m v rn 1- 0 O— o 0 o c o 0 a' a N Z Q �- g Y Q Q^. W fr c 0 0 0 0 0 0 p Q LL O0. 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J -r- C > o E U � E. > + co u it u N X 3 O LL Interwest Consulting Group RATIONAL METHOD PEAK RUNOFF (City of Fort Collins, 10-Yr Storm) ' LOCATION: Elizabeth & City Park Corner Redevelopment PROJECT NO: .1156-097-00 COMPUTATIONS BY: smb DATE: 5/2/2012 ' 10 yr storm, Cf = 1.00 DIRECT RUNOFF CARRY OVER TOTAL REMARKS Design Point Tributary Sub -basin A (ac) C Cf tc (min) i (iNhr) Q (10) (cis) from Design Point. Q (10) (cfs) Q(10)tot (cfs) Existing 0.52 0.92 5.0 4.87 2.3 2.3 Proposed 0.52 0.89 5.0 4.87 2.2 2.2 1 0.19 0.95 5.0 4.87 0.9 0.9 Roof Drainage to 12" PVC via 6" lateral 1 2 0.25 0.92 5.0' 4.87 1.1 1.1 On site parking lot to 12" PVC 1 3 0.12 . 0.94 5.0 4.87 0.5 0.5 Off -site parking to 12" PVC 4 0.07 0.67 5.0 4.87 0.2 0.2 On site directly to Street Interwest Consulting Group RATIONAL METHOD PEAK RUNOFF (City of Fort Collins, 100-Yr Storm) ' LOCATION: Elizabeth & City Park Comer Redevelopment PROJECT NO: 1156-097-00 COMPUTATIONS BY: smb DATE: 5/2/2012 ' 100 yr storm, Cf = 1.25 DIRECT RUNOFF CARRY OVER ITOTAL REMARKS Des. Point Area Design. A (ac) C Cf tc (min) i (in/hr) Q (100) (cfs) from Design Point Q (100) (cfs) Q(100)tot (cfs) 0 Existing 0.52 1.00 5.0 9.95 5.1 5.1 0 Proposed 0.52 1.00 5.0 9.95 5.1 5.1 0 1 0.19 1.00 5.0 9.95 1.9 1.9 Roof Drainage to 12" PVC via 6" lateral 1 2 0.25 1.00 5.0 9.95 2.5 2.5 On site parking lot to 12" PVC 1 3 0.12 1.00 5.0 9.95 1.2 1.2 Off -site parking to 12" PVC 0 4 0.07 0.84 5.0 9.95 0.6 0.6 On site directly to Street F s,, k Deslgn Procedure Form Ram Garden°(RGj W ti k ; »., Sheet 1 of 2 Designer: ES Company: Interwest Consulting Group ' Date: May 1, 2012 . Project: Elizabeth and City Park Location: ' 1. Basin Storage Volume z A) Effective Imperviousness of Tributary Area, 18 la = 100.0 (100 % if all paved and roofed areas upstream of rain garden) ' B) Tributary Area's Imperviousness Ratio (i = 1./100) i 1 000 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV ,,: D 40 , watershed inches (WQCV= 0.8 " (0.91" i3 - 1.19 " iZ+ 0.78 ' i) D) Contributing Watershed Area (including rain garden area) Area 22,500 sq It E) Water Quality Capture Volume (WQCV) Design Volume Vwocv -7'750F„z'? cu ft Vol = (WQCV / 12) " Area F) For Watersheds Outside of the Denver Region, Depth of d6 = in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, " VwoCV OTHER ;.ry Cu If ' Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VwOCv USER = cu ft (Only if a different WQCV Design Volume is desired) 1 2. Basin Geometry A) WQCV Depth (12-inch maximum) Dwocv = 12 in B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 0.00 ft / ft ' (Use "0" if rain garden has vertical walls) C) Mimimum Flat Surface Area Alin _ � ,.5615�a"(a sq It ' D) Actual Flat Surface Area AAcwy = 465 sq ft ACTUAL FLAT AREA < MINIMUM FLAT AREA u E) Area at Design Depth (Top Surface Area) . AT, = 544 sq ft F) Rain Garden Total Volume VT=�.>505 cu it TOTAL VOLUME < DESIGN VOLUME (VT= ((ATw + AAcmJ / 2) ' Depth) . 3. Growing Media L0o� hoose One r 18" Rain Garden Growing Media Other (Explain):11 ' 4. Underdrain System Choose One A) Are uniierdrains provided? OO YES K= O NO . B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y= 30.0 ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours V0112 75Q cu ft ' iii) Orifice Diameter, 3/8" Minimum Do =VKZ,"„.J'O-dd-77k, in . MINIMUM DIAMETER = 316" ELL UD-BMP_v3_01 Rain Garden.xis, RG 5/1/2012 1:21 PM r, ' r Design Procedure Form Rain Garden (RG) �F Sheet 2 of 2 Designer: ES Company: Interwest Consulting Group Date: May 1, 2012 Project: Elizabeth and City Park Location: 3 g 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric Choose One O YES A) Is an impermeable liner provided due to proximity NO. of structures or groundwater contamination? 6. Inlet / Outlet Control Choose One H? O Sheet Flow- No Energy Dissipation Required A) Inlet Control - 0 Concentrated Flow- Energy Dissipation Provided Choose One 7. Vegetation O Seed (Plan for frequent weed control) Plantings O Sand Grown or Other High Infiltration Sod 8. Irrigation Choose One A) Will be irrigated? O YES ONO the rain garden Notes: UD-BMP_v3_01 Rain Garden.xls, RG 5/1/2012, 1:21 PM ' Area Inlet Capacity P tY ' Roof Drain LOCATION: ELIZABETH AND CITY PARK PROJECT NO: 1156-097-00 COMPUTATIONS BY:, SB SUBMITTED BY: INTERWEST CONSULTING GROUP DATE: 5/2/2012 Inlet Data: Weir Length 2.1 ft ' Open Area 0.2 f A2 ' Solve for h using Orifice Equation Q = C.A. sgrt(2gh) where Qo = flow through orifice (cfs) Co = orifice discharge coefficient g = gravitational acceleration = 32.2 ft/s A. =effective area of the orifice (ft2) h =head on the orifice (ft) ' = 0.42 cfs 10- Event Qo Yr Ao = . 0.20 ft2 ' Co = 0.65 Solve for h: 0.17 . ft Solve for h using Weir Equation . ' Q=.CLHsiz where C = weir coefficient ' H = overflow height L = length of the weir Q = 0.42 cfs C = 3.00 L = 2.1 ft Solve for H: 0.16 ft ' ORIFICE CONTROLS Q= . 0.42 cfs Required Head d= 0.17 ft ' Available Head Prior to Overtopping 0.17 ft Attach $25 application fee, payable to Floodplain Use Permit page 1 updated ol/os. City of Fort Collins. If floodplain analysis (City of Fort Collins Code, Section 10-27) is required, attach additional $300 for a total fee of $325. Petitioner name John Musa, Elizabeth & City Park Corner LLC Address 1107 City Park Ave, Ft. Collins, CO 80521 Phone 970-488-2070 Owner name Same as above Address Phone ' City State Zip Legal description and/or address of property Lot 2 of Eleventh Fairview Subdivision 1401 West Elizabeth Street ■ Description of proposed project (check all that apply): ❑ new structure ❑ addition ❑ remodel ❑ redevelopment ❑ mobile home/building ❑ attached garage ❑ accessory structure ❑ fill ❑ excavation ❑ change of use LMother (describe) Curb, gutter and sidewalk Existing use (check one): ❑ residential O non-residential ❑ mixed -use ❑ vacant ground • Proposed use (check one): ❑ residential O non-residential ❑ mixed -use ❑ other If non-residential or mixed -use, describe in detail: Street frontage for mixed use commercial • Critical facility? Dyes Ono building ' Type of foundation (check one): ❑ slab -on -grade ❑ basement ❑ crawl space (attach pg.3, crawl space worksheet) ❑ enclosed area not subgrade ❑ other (describe) na ' Remodels and Redevelopment Only • Cost of improvement for this project: (submit itemized cost list of improvements) na • Value of structure: (submit County assessor's or appraiser's valuation of structure) na • Cumulative value of improvements: na • Substantial improvement? Dyes ❑ no na Section C Floodpin Informat�o° ai _ x ' Vertical Datum Conversion • Floodplain designation: ❑ Poudre River ❑ FEMA basin 0 City basin NGVD 29 + 3.O ft. = NAVD 88� • Floodplain name: Canal Importation. Floodplain (Ayres As Bui1-t)---__'___- =_"___ ' FEMA base flood elevation (BFE) (if applicable): na, NGVD 29 NAVD 88 • FEMA zone (check one): ❑ A ❑ AE ❑ AH ❑ AO ❑ X-500 ❑ X na • City floodplain BFE: (if applicable) 5 03 3 .1 NGVD 29 Zone: 0100-year • Regulatory flood elevation (highest BFE + freeboard) S034.6 NGVD 29 NAVD 88 ' (freeboard requirements on pg.2) • Floodway: Oyes ❑ no (If yes, include technical evaluation that shows "no- rise"per City Code 10-45.) • Erosion buffer limit: ❑ yes Ono page 2 • Structure is: ❑ elevated ❑ floodproofed ❑ vented ® n/a • If floodproofed, describe method used: • Benchmark used: COFC BM 1- 03 Elevation of benchmark: 5046.12 NGVD 29 • Lowest existing ground elevation: 5031.0 NGVD 29 Highest existing ground elevation: 5034 . 6 NGVD 29 Lowest finished ground elevation: 5031.0 NGVD 29 Highest finished ground elevation: 5035.2 NGVD 29 • Lowest floor elevation (Refer to City Code 10-37(d)): na NGVD 29 NAVD 88 • Elevation of garage slab: na NGVD 29 na NAVD 88 • Lowest elevation of HVAC equipment: NGVD 29 NAVD 88 • Enclosed area (not elevated or floodproofed): na square feet • Number of vents: na Area of venting: square inches • Requesting variance from City Code ❑ yes ® no ' (Ifyes, attach variance application with additional $300 variance fee. Variance application can be obtained from Fort Collins Utilities. Variance request requires consideration by the Water Board.) • Requesting waiver based on capital project construction in City -designated floodplain Dyes - ® no ' (If yes, attach waiver application which can be obtained from Fort Collins Utilities. Waiver request requires consideration of Utilities General Manager.) For structures: Attach building plans showing foundation design, flood elevation, floor elevations, HVAC.elevations, size and location of vents, floodproofing design and other relevant information. For site work: Attach site and grading plans and other relevant information. For propertyin a floodway: Attach No -Rise Certificate and documentation. Signature of petitioner: Signature of owner:. Freeboard requirements: City Code 10-37 Poudre River: Twenty four (24) inches above the base flood elevation. • FEMA basin AND City basin floodplains: —New construction and redevelopments: eighteen (18) inches above base flood elevation. ..—Additions and substantial improvements: six (6) inches above base flood elevation. .—Accessory structures: six (6) inches above base flood elevation or meet venting requirements. If you have questions or need assistance filling. out forms, contact Fort Collins Utilities at: • Phone: (970) 221-6700 ' TDD: (970) 224-6003 • Web:fcgov.com/stormwater • E-mail: utilities@fcgov.com F�6�roC ollins Utilities 3 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Freeboard T F Vent rawl space C No more than A Velocity < 5 ft. per sec. �'ertrca �Daturri��onversr'on NGUD29+3 DaftN�AUD88,- 1. Velocity of.flood flows hitting structure (Figure A): (less than 5 ft. per sec.) 2. Flood elevation: NGVD 29 NAVD 88 3. Elevation of bottom of crawl space: NGVD 29 NAVD 88 4. If the elevation of no. 3 .is lower than 2, provide the distance between the bottom of crawl space and the lowest adjacent grade (Figure 8): (Maximum 2 ft.) 5. Height of crawl space (Figure C): ft: (Maximum 4 ft.) Measure from lowest interior grade of crawl space to top of foundation wall. Additional requirements checklist ❑ Describe interior drainage system: ❑ Pump is totally immersible. (Figure D) . ❑ All HVAC, including ductwork, is above the regulatory. flood protection elevation. (Figure E) ❑ Hot water heater is above the regulatory flood protection.elevation. ❑ Electrical is above the regulatory flood protection elevation. City of Fort Collins Utilities "NO -RISE" CERTIFICATION This is to certify that I am a duly qualified registered professional engineer licensed to practice in the State of Colorado. It is further to certify that the attached technical data supports the fact that the Proposed. Elizabeth & City Park Comer Redevelopment (Name of Development) will not impact the 100- year flood elevations, floodway elevations, or floodway widths on the Canal Importation Floodplain (Name of Stream) at published or unpublished cross -sections in the FEMA Flood Insurance Study.or the City of Fort Collins Flood Study dated Ayres Daft As Built 2012 (Wafer) (Study Dates) in the vicinity of the proposed development. Attached are the following documents that support my findings: 1.) PROPOSED BUILDING GRADING PLAN AND FLOODPLAIN PLAN 2.) DRAINAGE LETTER DATED 9-25-12 3.) Signature: Name (printed): Michael Oberlander Company Name: INTERWEST CONSULTING GROUP Date: 09-25-12 P.E. Stamp Revised 10/19/05 INTERWEST CONSULTING- G R O U P ' September 25, 2012 rMs. Marsha Hilmes-Robinson Floodplain Administrator City of Fort Collins Stormwater ' 700 Wood Street Fort Collins, CO 80525 RE: Elizabeth and City Park Corner Redevelopment Dear.Marsha, Attached is information for the Floodplain Use Permit for the above referenced project. This project will include removing and widening approximately 142 lineal feet of existing sidewalk as well as adding approximately 24 lineal feet of.curb and gutter to replace an existing driveway cut along Elizabeth Street. The curb, gutter and a portion of the sidewalk is within the floodplain and floodway of the Canal Importation basin. Please note that we have received a waiver from the City dated September 24, 2012 to utilize the Ayres and Associates DRAFT "As -Built Floodplain Modeling Report for Canal Importation Ponds and 0utfall Project" dated 2012.(CIPO r LOMR). The street frontage. work in the floodplain is associated with the redevelopment. of the existing lot at 1401. Elizabeth Street. The new structure will be located. outside of the CIPO LOMR floodway and floodplain. ' There be fill will no associated .with the proposed curb, gutter and sidewalk. The existing walk will be removed and replaced at existing grade. The existing drive cut will be removed and replaced with the same concrete section as the adjacent curb, gutter and sidewalk. The hydraulic modeling does not account for this existing drop in the curb at the driveway, therefore, no rise is associated with this construction. tConstruction staging for this project will occur in.the south portion of the lot which is located out of the CIPO LOMR floodplain. I appreciate your time. and consideration in reviewing this request. Please call me at 970-674-3300 ext. 102 if you have any questions. Sincerely, Michael Oberlander, P.E. s. 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ................. .... 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I � ' 0 Yt 1 I I �\ ------------=------- - - - I 1 ------ - ---- --, it - �� , tl 1 I I 1 II ill 0 City of F6rt Collins b' DATE: September 24, 2012 Utilities electric - stormwater, wastewater.. water 700 Wood Street PO Box 580 Fort Collins, CO 80522 970.221.6700 970:221.6619 — tax 970.224.6003 TDD utilities @lcgov, com fcgov.comlutifities ' TO: Brian Janonis, Utilities Executive Director FROM: Brian Varrella, Floodplain Administrator` 4� Ken Sampley, Stormwater & Floodplain Manager J REt Floodplain waiver request for 1401 W. Elizabeth St. U.- 1.0 EXECUTIVE SUMMARY A new commercial development project is proposed for the parcel at 1401 West Elizabeth Street in the Canal Importation floodplain and floodway. The property is located downstream of improvements associate with the Canal Importation Ponds and Outfall (CIPO) project. Capital improvement construction was functionally completed in December 2011, and the draft as -built hydrologic and hydraulic report was prepared in February 2012 and will herein be referred to as the.,CIPO Letter of Map Revision (LOMR). The post -construction floodplain boundary revisions documented in the CIPO LOMR show the parcel at 1401 W. Elizabeth St. is almost completely removed from the floodplain. Therefore, proposed development activities at this address can benefit from a floodplain waiver. The: waiver permits the use of the CIPO LOMR post -project floodplain boundaries as effective despite the fact they have not been formally approved as an update to the Stormwater Master Plan by City Council. Your review and approval of this waiver will permit the proposed development's forward movement with the benefit of the best available data provided in the CIPO LOMR, consistent with the standards of Section 10-144 of Chapter 10 of the. Fort Collins Municipal Code. 2.0 BACKGROUND. & REQUEST The proposed project includes the construction of a new commercial structure with parking and water quality improvements.. Convenience store and restaurant uses are expected in the structure. A new 12-ft attached sidewalk will be constructed at the northern edge of the parcel near Elizabeth Street. At the time of this memorandum the previous structure, formerly operated as Consuelo's.Mexican restaurant, has been demolished. Page 1 of 4 SAWEFS\StmWtAlT Admin lettersTrojcct Now-Sheets\2012\Canal Importation\Elizabeth W 1401\Elizabcth W 1401 waiver.docx The current effective hydraulic model on West Elizabeth Street was established by Anderson Consulting Engineers (ACE 2001) as part of the.Canal Importation Basin Master Plan in 2001. The City contracted with ACE and Ayres Associates to update the hydraulics and hydrology in the Canal Importation Basin following the CIPO capital project improvements (Ayres 2012). The updated hydrologic and hydraulic models, drafted February 2012 and currently under staff review, have not been adopted by City. Council at this time. ' The development review team for the proposed project at 1401 W. Elizabeth has requested a waiver to use updated hydraulic information at the development site. This is to their advantage financially and architecturally as high risk flood hazards have been removed from the parcel by CIPO Project conveyance improvements upstream. 2.1 Current Effective Flood Conditions The current effective flood risk map in Attachment A shows a portion of the parcel at 1401 W. Elizabeth is located within the City 100-year flood fringe and adjacent to the floodway. A BFE interpolation is calculated on the flood risk map and is reported as 5034. 6 ft-NGVD29. The current effective water surface elevation table is included as Attachment B. ' 2.2 Post-CIPO Flood Conditions The proposed building is to be located at the northwest comer of the parcel; within the ' current effective 100-year flood fringe. Chapter 10 requires this new construction to elevate the lowest floor at least 1.5 feet above the base flood elevation (BFE), or floodproof to the same. ' The hydraulic information documented in the draft CIPO LOMR and included as Attachment C shows the parcel will be outside the post-CIPO flood fringe and I floodway, with the exception of a couple feet of sidewalk. It must be re -iterated that the CIPO documentation is still under review, and redline comments are visible in Attachment C. Attachment D includes a site plan with post-CIPO LOMR flood fringe and floodway boundaries. The flood fringe will. be 15.1 feet from the building at the closest point, ' which is also the northeast comer of the proposed building. This- document shows post- project hydrology and hydraulics have removed'all floodplain boundaries and subsequent Chapter 10 Code requirements from developable lot; including the requirement to elevate or floodproof new non-residential structures. There will, therefore, be no BFE to record. for the new structure on this site and no floodplain use permit will be required for the non-residential structure should the waiver be approved. ' (continued, next page) Page 2 of 4 ' City Q# F'or Collins 3.0 APPLICALBE CITY CODE The proposed project at 1401 W. Elizabeth Street is subject to the following sections of Chapter 10 of City Code: • §10-139(1) — new nonresidential construction is permitted in the flood fringe of a City basin, including the proposed new building, as long as the `standards of 10- ' 37 or 10-38 are satisfied. This requirement can be waived by the provisions of §10-144. • §10-37(c)(3)(a) — new nonresidential structures must be elevated at least 18 inches above the BFE. The proposed building will exceed this 18 inches of f freeboard. §10-135.- new nonstructural construction is permitted.in the floodway of a City basin, including concrete. flatwork, site work and landscaping, as long as the standards of 10-45 are satisfied. This will be required under a floodplain use permit and no -rise certification prepared and sealed by the development team's ' professional engineer (P.E.). • § 10-45 all development, obstructions or activities in the floodway will be proven and documented to cause no rise in the BFE and no change to the floodway ' boundary by a registered P.E. licensed to practice in Colorado. • §10-144:--requirements in a City Basin may be waived and a floodplain use permit issued if the General Manager is satisfied that there is a sufficient degree ' of certainty that the property will be removed from the floodway or flood fringe as a result of a City funded capital project. This assessment is subject to consideration of, (1), the nature of the proposed development and related flood ' risks, (2), the level of certainty the capital project will continue to completion, and (3), a technical analysis completed by a registered professional engineer. • §10-27 -.a floodplain use permit and attached no -rise certification documentation ' will be completed and approved prior to mobilization. 4.0 RECOMMENDATION Stormwater staff hereby recommends approval of the waiver to use CIPO LOMR hydraulic and hydrologic information to remove flood hazard boundaries from the parcel ' at 1401 W: Elizabeth Street. The standardsY . of §10-144 have been duly satisfied and adequately documented, though it is acknowledged the technical analysis and associated report produced by Ayres (2012) needs some revision and correction, and should be stamped by a registered P.E. licensed to practice in the State of Colorado. We do not anticipate any changes to the floodplain boundary in the project area at. this time, and not, the waiver can be approved with reasonable certainty that the post - construction floodplain delineation is accurate. ' The staff in the Stormwater Division is available for any questions, comments or clarifications. Page 3 of 4 G� �®rtyoottins 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 5.0 REFERENCES Anderson Consulting Engineers, Canal Importation Master Drainage Plan. Volumes I - III, including body text and Appendices E and F (2001). Ayres_ Associates, DRAFT; As -Built Floodplain Modeling Report for Canal Importation Ponds and Outfall Project (CIPO). Includes body text and attachment in first volume (DRAFT 2012). City of Fort Collins (CoFC), City of Fort Collins Municipal Code, Chapter 10, Flood Prevention and Protection. (2007). Available at hftlp://www.f,pgov.co.m/utilities/imo/site to specific/uploads/ floodolain. Ch 10 Update 2010..bdf. 6.0 ATTACHMENTS. Attachment A. Current Effective City Flood Risk Map (2001) Attachment B. Current Effective Table of Water Surface Elevations (2001) Attachment C. Post-CIPO Floodplain Map (2012) Attachment D. Preliminary Site Plan from Development Team (2012) Page 4 of 4 ' City Floodplain,Waiver Form (Based on City of Fort Collins Code, Section 10-.114 or 10-144) Sectio"n"k Property Enformatibh Property address or legal description 1401 West l..lrzabeth Street, Parcel #97154-25-002 ' Michael Oberlander, P.E. _ Applicant name Phone 970-674-3300 Applicant address . 1218 W. Ash St., Suite C, Windsor, CO 80550 Section B Proposetl Project InformationV"W �g g �1 • Description of proposed project (check all thatapply):10 new construction additionE]remodelElredevelopment ❑accessory structure Qflll R]excavation Dchange of use other (Attach additional descriptions and drawings as necessary.) • Current use (check one):Dresidential R non-residential ❑mixed -use Ovacant ground • Proposed use (check one): Dresidential 0✓ non-residential ❑ mixed -use bother • If non-residential or mixed -use; describe use in more detail: Commercial uses; convenience store & restaurant • Foundation type (check one): slab on grade0basementOcrawl space ❑ enclosed area above grade • Base flood elevation (100-year flood level): 5034.6 ftNGVD (City) N/A (FEMA) Regulatory flood protection elevation: Not Applicable • Floodplain designation: [:IFEMA QCity Floodplain name: Canal Importation Floodway:R]yes 0 no • Proposed lowestfloorelevation (refer to City Code i o-37(d)): 5034.5 ft-NGVD29 (See Attachment D) (atrachdrowing) ' Name of capital project that will remove property from floodplain: CIPO • Section(s) of City Code for which a waiver is being requested: _10 1390 )' and 10-37?C)(3)i`a) • What is the waiver request? Request to use post-CIPO construction draft hydrologic & hydraulic information to remove a proposed building footprint from the flood fringe and from the standards of Chaoter 10 of City Code. The applicant hereby certifies that the above information, along with the attached plans and project descriptions: are correct. The applicant ' agrees to comply with the provisions of the zoning ordinance, building code, all other applicable sections of City Code, Land Use Code, City Plan and all other laws and ordinances affecting the construction and occupancy of the proposed building. The applicant understands that if this waiver is approved, the structure and its occupants may be more susceptible to flood damage and, ifin a FEMA floodplain, the cost of flood insurance may increase for the property. ' The applicant understands that new structures that are constructed pursuant to this waiver and upon completion of the relevant capital project, are determined to not have been.removed from the floodway or flood fringe,as anticipated at the time of said waiver and will be deemed to be non -conforming structures and all future activities and development shall be subject to the requirements of Chapter 10 of City ' Code as the same would apply to any noncoNorrwng stri ture: J J-0 Signature of applicant: I Date: _. Capital project Notice to Proceed date: M.2'W ,Expected capital project completion datef . Technical analysis for capital project: 0 Capital project will completely remove property from floodplain (che&one) :U yes a. no M unsure 3. Notes: .1 -c I r, _._-. ao C Waiver: c`approved hl deni . Utilities General. Manager, Date �� hoodprain verIorm. t/06 '"00 t at ct� �.. ATTACHMENTA .x { �z �', -„� °�i',yi � .. �a���..�n:' ...;gat �•t�' � ?+.iR ..�.r.. �t`�'��, � N � BFE Calculation by Linear Interpolation 1401 'W .Elizabeth St. ' ? A = 0.00 ft, X = 6035.1 ft B = 36.75 ft, Y = BFE at 1401 W. Eliz: C = 149.38 ft, Z 5032.9 ftz (Y-Z) ! (B-C) _ (XZ) / (A-C) Y = Z + (B-C) *' (X Z) / (A-C) Solve for BFE at 1401 W. Elizabeth St. Y = 5034.6 ft-NGVD29 City Flood Risk High Risk Map This information is based on the Federal Emergency Management CityFloodwa Area of 100- ear floodplain with greatest depths and cy g ti - Y P 9 P Agency (FEMA) Flood Insurance Rate Map (FIRM) and the City of. fastest velocities. Fort Collins Master Drainageway Plans. This letter does not imply that the referenced property will or will not be free from flooding or City Flood Fringe -May InClUder damage. A property not in the Special Flood Hazard Area or In a Areas of FEMA 100-year floodplain (FEMA Zones A, AE, AO, and AH) City Designated Floodplain may be damaged by a flood greater ' - Areas of City 100-year floodplain including ponding areas and sheet than that predicted on the map or from a local drainage problem flow areas with average depths of 1-3 feet. not shown on the map. This map does not create liability on the There is a 1 %annual chance that these areas will be flooded. part of the City, or any officer or employee thereof, for any damage that results from reliance on thisinfonnation. Moderate Risk All floodplain boundaries May include: -Areas of FEMA500-year floodplain (FEMA Zone X-shaded). are approximate. City of -Areas of FEMA or City 100-year floodplain (sheet flow) with FQI�t Collins average depths of less than 1 foot. - Areas protected by levees from the 100-year flood. N S Low Risk w E 0 25 50 too 150 200 ®Areas outside of FEMA and City mapped 100-year and 500-year Feet floodplain. Local drainage problems may still exist. S Printed: 09/21/2012 ]ATTACHMENT B� Elizabeth Street/Constitution Avenue Flow Path - Water Surface Profiles Water Surface Elevation ft,NGVD) Elizabeth Street -- Shields Street to City Park Avenue Cross Fully -Developed Condition Section Location 2-Year 10-Year 100-Year 100 5022.6 5022.9 5023.9 Centedine of Shields Street 180 5022.7 5023.3 5024.2 415 5023.0 5023.3 ( 5024.5 565 5023.9 5024.3 5025.3 770 5024.9 5025.4 5026.E 895. 5025.9 i 5026.1 ` 5027.2 1065 5026.4 5026.7 5027.6 1335 5028.4 5028.9 5030.2 1440 5029.E . E: 5630.5 6031.4. Centerline of City Park Avenue CSU International House -- city Park Avenue to LCC No. 2 Cross Fully -Developed Condition Section location .2-Year 1 10-Year : 100-Year 1495 5031.9 5032.7 5033.1 U/S of Sizabeth/Clty Park Intersection 1645 5032.3 5033.1 �^ 5033.7 v.05 5033.4 5034.0 '< 5034.6 .2095: 5038.0 5035.8 ..5037.0 Lltream limit of sub -reach dEllzabeth,,Street = C 'Park Avenueato, ;' an Avenue . Cross Fully -Developed Condition Location Meet 1495 5031.6 .. 5031.8 .f 5032.9 S,of_GtyUPark Avenuezf ` 1645: ..5.033.7 5033.9 5035:1 2135=5036.35036.6, F 5038.8 2335.1 b042 5 D/S of Larimer County Canal'No. 2 2535 .1 5045.2 East side of B an Avenue Elizabeth Street - Bryan Avenue to Constitution Avenue Cross Fully -Developed Condition ILocation Section I 2-Year , . 10-Year , 100-Year 2690 5044.4 1 5045.0 5046.5 , West side of Bryan Avenue ,2860 11 5046.9 1 5648.8 5048.5 1 East side of Constitution Avenue Bryan Avenue -- Constflutf m Avenue to Springfield Drive Cross Fully -Developed Condition Section Location, . 2_Year. :10=Year 100-Year 3085 5045.1, 5045.5 5046.9 Bryan Avenue . 3205 5045.6 5045.5 5046.8 3380 5046.5 „ 5046.5 5046.9 Bryan Avenue 3480 046.9 5046.9 50472 Springfield Drive 3600 51348.0 5648.1 .. 5048.6 Springfield Drive 3716 5048.7 5048.8 50492 Constitution Avenue 3660 5049.5 5049.9 50502 4020 5050.3 5050.7 5051.0 U/S limit of subreach ©lzabeth Street - Constitution Avenue to NMD Cross Put -Develo ed Condition Section Location 2-Year r� 10-Year 100-Year 3080 50472 ._ 50472 5049.1 West side of Constitution Avenue 3245 5047.7 5047.7 !: 5049.1 3450 5050.0 > + .. 5050.0 5 05 1.2 ` D/S of NMD Lake Court - Constitution Avenue to NMD Cross Fully=Developed Condition I Section 2-Year. 10=Year ; 100-Year. . Location . 3026 504T6 5047.8 5049.2 ` East End of Lakeridge Court 3240. 5048.4 5048.4 5049.3 3390: 5049.3 SO49.3 5049.5 East of Avary.park Pond FUename. WATER SURFACE PROFILES -EX AND DEV xds Sheet Epzabeth Page 1 of 1 *.,E n ' �-- t; Z., W a• ..... ems...... otozeerocs3Noxa 12a00009Mr110'J! nr was un toll a'r'1 Inlmo�mra uuvlwwam NVid39vNwmclemvidaoo9d .. p �` J !d NOISWC6,7S /NlaWiltld HlN3/1313'Z 10'1 1Pf3WdOl3/19G3tlL3NM0, M2,Vd111�@H,39Yff� 5 ^ -_ e 8 e>� o J: e ttg@g@ � eFyp )• Lgq R �v LLc§ �5