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HomeMy WebLinkAboutTHE ELLIE AT OLD TOWN NORTH - PDP240002 - SUBMITTAL DOCUMENTS - ROUND 2 - Drainage Related DocumentPDP DRAINAGE REPORT The Ellie at Old Town North Old Town North 5th Filing Tract A . for: Van Horn Development Management, LLC 14143 Denver West Parkway #100 Golden, CO 80401 enganeer: TJC Limited 8751 E Hampden Ave, Suite B10, Denver, CO 80231 Jan�es W. Allen, PE 303.489.3346 � www. jcivil.com June 19, 2024 Preliminary Drainage Report Page 2 of 8 TABLE OF CONTENTS �, C COVER LETTER ..........................................................................Error! Bookmark not defined. GENERAL LOCATION AND EXISTING SITE INFORMATION ............................................. 4 MASTER DRAINAGE BASIN INFORMATION ........................................................................ 4 FLOODPLAIN INFORMATION .................................................................................................. 5 PROPOSED DRAINAGE FACILITIES .......................................Error! Bookmark not defined. DRAINAGE DESIGN CRITERIA ................................................................................................. 6 VARIANCEREQUESTS ............................................................................................................... 7 EROSION CONTROL ................................................................................................................... 7 CONCLUSION............................................................................................................................... 7 REFERENCES............................................................................................................................... 8 APPENDICES................................................................................................................................ 8 Preliminary Drainage Report Page 3 of 8 �, C I hereby attest that this report for the preliminary drainage design for the Ellie at Old Town was prepared by me or under my direct supervision, in accordance with the provisions of the Fort Collins Stormwater Criteria Manual. I understand that the City of Fort Collins does not and will not assume liability for drainage facilities designed by others. James W. Allen Licensed Professional Engineer State of Colorado No.42256 Preliminary Drainage Report Page 4 of 8 GENERAL LOCATION AND EXISTING SITE INFORMATION a) Site Location Description i. ii. �, C The site is located in Section l, Township 7 North, Range 69 West of the 6ti' Principal Meridian, County of Larimer, State of Colorado. Also known as Old Town North 5`h Filing, Tract A. A vicinity map is attached in appendix A. iii. The property is adjacent to Sungia Rd, Blondel St, and Alleys. iv. Adjacent land uses are residential Old Town North filings. v. The project is within North East College Corridor Outfall (NECCO) Basin 810. The project is with Old Town North Filing 3 Basin 7. vi. vii. The existing site generally slopes west to east. There are two existing 18" RCP culverts that outfall the site under Blondel Street. These culverts were constructed for interim flows during the development of the area. These flows were eliminated when the NECCO improvements were completed. There are no irrigation facilities on-site. viii. The land is currently vacant. ix. The property is covered with natural grass. Slopes range from 2% to 7°/o. x. Soils consist of Nunn clay loan with Hydrologic Soil Group C. A NRCS Soils Classification Map is attached as appendix B. MASTER DRAINAGE BASIN INFORMATION a) The site is located in the Lower Dry Creek Basin. The site was situated in the Dry Creek floodplain when the original Old Town North plat was recorded in 2004 and Old Town North was developed. The Dry Creek floodway has since been redefined to remove a majority of the site from the Dry Creek floodplain_ The immediate area adjacent to the property is fully developed with residential use. i. The subject property is within the Old Town North Third Filing and 2009 NECCO study. The project runoff will conveyed through existing stormwater facilities to the NECCO Detention pond north of Sungia Road. ii. NECCO assumed a 90% imperviousness (developed condition). b) Site Drainage Basins i. The site is composed of one historic sub-basin and no offsite sub-basins: Sub-basin HI — consists of grass covered vacant land. Runoff sheet flows east to the existing 18" RCP culverts under Blondel St. Sub-Basin Design Area 2-Year 100-Year Point (acres) Runoff Runoff (cfsl (cfsl Preliminary Drainage Report Page 5 of 8 H1 I H1 I 0.81 0.26 1.08 c) There are no irrigation facilities on or adjacent to the property. �, C FLOODPLAIN INFORMATION a) The site is within a Zone X accarding to FEMA Flood Insurance Rate Map No. 08013C0411K (appendix C). b) The site was situated in the Dry Creek floodplain when the original Old Town North plat was recorded in 2004 and Old Town North was developed. The Dry Creek floodway has since been redefined to remove a majority of the site from the Dry Creek floodplain. PROJECT DESCRIPTION a) The project proposed two apartment buildings with tuck under garages. Surface parking is being provided on the west end of the site. The existing alley will be widened. A rain garden in proposed to meet Ft Collins LID requirements. b) The site is approximately 0.81 acres. PROPOSED DRAINAGE FACILITIES a) The project site is composed of four sub-basins and no offsite sub-basins: Sub-basin A— consists of roof, pavement, and landscaping. Runoff flows off-site undetained to the western ally and conveyed via an existing gutter pan to the south towards Emmaus Ln south of the site at Design Point 1. Sub-basin B— consists of roof, pavement and a rain gardens. Runoff flows down the private drive to a curb cut and into the rain garden. The rain garden outfalls into one of the existing 18" RCP culverts under Blondel St at Design Point 2. Existing 18" Capacity: 801f 18" RCP @ 0.2% capacity = 4.71 cfs. 100 year runoff for Basin B is 4.65 cfs and therefore okay. Sub-basin C— consists of sidewalks and landscaping. Runoff sheet flows into Sungia Rd and into an existing storm inlet at the corner of Sungia Rd and Blondel St at Design Point 3. Sub-basin D— consists of sidewalks and landscaping. Runoff sheet flows into Blondel St at Design Point 4. Sub-Basin Design Area 2-Year 100-Year Point (acres) Runoff Runoff (cfsl (cfsl Preliminary Drainage Report Page 6 of 8 A 1 0.16 0.31 1.28 � B � 2 0.47 � 1.22 4.65 C 3 0.11 0.09 0.36 � D � 4 0.06 I 0.07 � 0.28 �, C b) There is no on-site detention required for this project. c) A rain garden is proposed within Basin B to treat a minimum of 75% of the new impervious area. Site topography and the existing 18" RCP outfall limits the location of the rain garden bottom requiring the use walls to obtain sufficient storage volume and provide 6 inches of freeboard. � Total Iin ervious Area Added 26,054 sft Min Area Treated (75% far RG 19,541 sft Actual Area Treated 19,550 sft The rain garden has walls on all sides varying from 1.0-2.0 ft tall. Approximately 1.0 ft of the wall will extrude from the ground. d) LID techniques utilized in this design include minimizing directly connection impervious areas by discharging roof downspouts onto the surface. No stormwater will be piped except for the stormwater discharging from the rain garden. e) Maintenance of the rain garden can be performed from the private drive or Blondel Street (20 ft east of the facility). � A drainage easement will be provided over the rain garden. DRAINAGE DESIGN CRITERIA a) The subject property is within the Old Town North Third Filing and 2009 NECCO study. The project runoff will be conveyed through existing stormwater facilities to the NECCO detention pond north of Sungia Road. NECCO assumed a 90% imperviousness (developed condition). The previous studies have no impact to the proposed design. b) Four-step process a. Where possible, the runoff sheet flows across landscaping before discharging into Sungia Rd and Blondel St. b. A rain garden is proposed to treat a minimum of 75% of the new impervious pavement and roof areas. c. There are no streams within the project area to strengthen. d. A construction erosion control plan will be included with this project. c) Rainfall data is provided in table 3.4.1 IDF Table for Rational Method from the Fort Collins Stormwater Criteria Manual. d) Design frequencies used in this design: Minor: 2-year Maj or: 100-year Preliminary Drainage Report Page 7 of 8 �, C e) The Rational method was used to calculate hydrological data following the Fort Collins Stormwater Criteria Manual chapter S.OThe peak runoff from minar and majar storm events are calculated using the Rational Method formula as detailed below: Q=CIA Where: Q= Storm runoff in cubic feet per second (cfs) C= Runoff Coefficient I= Runoff intensity in inches per hour A= Drainage area in acres Runoff coefficients were obtained from Table 3.2-2. Times of concentralion were calculated based on the initial time or overland flow time (for urbanized undeveloped basins < 300' overland flow), with a minimum time of concentration of 5 minutes. t; = 1.87(1.1 - Cs��L � 50.33 MANUAL Eqn. (3.3-2) V= 1.49/n RZ�3S1iz MANUAL Eqn. (5-4) tt = L /(60V) MANUAL Eqn. (5-5) t� = t; + tt MANUAL Eqn. (5-3) MAX. t� = L/180 + 10 MANUAL Eqn. (3.3-5) � No on-site detention is required as part of this project. g) No public streets requiring capacity calculations are required as part of this project. h) The rain garden outlet structure is sized using weir flow calculations. i) No storm sewer pipe networks are included with this project. j) No swale or channels are included with this project. k) No emergency spillways are included with this project. VARIANCE REQUESTS a) No variances are requested as part of this project. EROSION CONTROL a) This report is in compliance with all erosion control materials within the final Erosion Control Report and Plans. CONCLUSION a) Compliance with requirements — this design complies with the requirements of the city of Fort Collins and master drainage plans referenced in this report. b) Drainage plan effectiveness — this design effectively routes developed flows throughout the site and provides water quality for at least 75% of the new impervious areas. This design does not impact adjacent properties. Preliminary Drainage Report Page 8 of 8 REFERENCES �, C 1. City of Fort Collins Stormwater Criteria Manuel, December 2018. 2. Urban Storm Drainage Criteria Manual, Volumes 1, 2, and 3, Revised March 2024 3. North East College Corridar Outfall (NECCO), August 2009. 4. Old Town North Third Filing, Drainage, Sediment/Erosion Control, and Stormwater Quality Report, June 2017 APPENDICES A. Vicinity Map B. FEMA Map C. Soillnformation. D. Old Town North Third Filing Excerpts E. Drainage Calculations F. Drainage Plans VR,+IIVI I T n�wr Appendix A National Flood Hazard Layer FIRMette 105°4'40"W 40°36'12"N I � ` � � �'� J � �� Y . � � � ~ W W � i - . r�, � • 1 ._ 11, �P� ,. . 1 'e � � � �;:��' _� � ' � �s 4 �f .1 . : .� 1 � � i L ^U', 'V� , � l���� •.. . ' � ��'I • �' � �; � '• �� �— „��- �; FEMA � _� ��. � + , - -- ! ., .� ._� / � - _ . � �. • � �. _� � T tT T.. *' � � r J �._ �_ � � �, � , ' ' . � . � �►1AREAOF MIt11ti1AL FL OD��A�ZA� � - � �- � � -� - _ ` [ . � �� � � � f � � � � .� _�� �..... �' �w''r►"�"r }f � � � � , � � • t-�* i� � • � , � � �►7�►e�'� t y � �T � � � �+ ; , r • � w -� { Ctn• or Fort Collm�#��"r f �• �-osoio�r"�' " , • • �r � t�-�CT ♦ m � - '�� � � '--s,� � ;. � � ~ � �.�Y � � i �IR69v; _t _ --;� � ��, �- � - �_ _ � � _.� i� �� ` M � �. • � �A � ' . ' � � �..1� ( )M 1R '� � . - ,.,; �. r �l� , : , . . ., . �' . ,.-.t �. . , , _���', � �r� • 1t 1' • � _ � b �� 1 �, l � . _' t. , C! F f, � s�l� • . --� � ,�� �`� . - � J I y � i �� � � . � � � ��� 1 Oh"f�; �' �x � �. ��� ��. r! � 1 1 1' � � u/ 1 U4 1 1At� ', ��'.%,,. T",-�t "` , t u�� r� �•A�I�IUAL CHA�ICE'FLOOD HAZARD" � s ��+ �� � � i . _ � ,,� - /� � , � -� _ ¢ ' �� ��� ♦� �! , .� : , r� x' ` � �'--__'_'-_ + r / / - ' ' � � ♦ �..��' �_--��� r�—��������.,�,` '` �� `�� �`` � , � ��� � � -���'�C1 _• � 0 ,_ ,.�# _ � *--- ,� _r � _ � I �� v� 4- _ ' � � '� :.; � � �� - .. � yY � � v� �:` � ���' � - � . .� ' ��' 0 250 500 - _[ — /-- Feet 1:6,000 1,000 1,500 2,000 Appendix B Legend SEE FIS REPORT FOR DEfAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT SPECIAL FLOOD HAZARD AREAS OTHER AREAS OF FLOOD HAZARD Without Base Flood Elevation (BFE) Zone A. V. A99 With BFE or Depth zone aE. ao. atf. vE, nR Regulatory Floodway 0.2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mile zo„� x � - _ � Future Conditions 1% Annual �_- Chance Flood Hazard zone x Area with Reduced Flood Risk due to Levee. See Notes. zone x Area with Flood Risk due to Leveezo�,e o NO SCREEN Area of Minimal Flood Hazard zone x 0 Effective LOMRs OTHER AREAS Area of Undetermined Flood Hazard zone o GENERAL ---- Channel, Culvert, or Storm Sewer STRUCTURES i i i i i i i Levee, Dike, or Floodwall � Cross Sections with 1%Annual Chance ��•5 Water Surface Elevation e - - - Coastal Transect �- Base Flood Elevation Line (BFE) Limit of Study Jurisdiction Boundary -- --- Coastal Transect Baseline OTHER _ — profile Baseline FEATURES Hydrographic Feature MAP PANELS Q Digital Data Available No Digital Data Available � Unmapped The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location. This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on 4/19/2024 at 2:17 PM and does not reflect changes or amendments subsequent to this date and time. The NFHL and effective information may change or become superseded by new data over time. This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for regulatory purposes. Basemap Imagery Source: USGS National Map 2023 Appendix C � Soil Map—Larimer County Area, Colorado � a � v v � 40° 35' S9" N — 40° 35' S9" N � f � • -�w�/' �► - _ �" �1 r � • ► ���, s� ,� � . �� � � � • � � i � �� . .� - *-' ' � � � �'- � �� � � � � � � — � a � � � - � � .� • ti � � ` �.` � �,� , ;� ' - . , + � � � �� � � _ , � * � $ �— � _� _ � � y r 1 � �y , � �; 1 �� � �— S,�oil Map may not be valici at�tli`is s�_l.��_c,�le. ,�� �. �� �_ � 40° 35' S7" N ^ � � � �� � I� � ��� I� �� I ao� 3s s�° N 493800 493810 4.93820 493830 493840 49.9850 49.'3860 493870 493880 4.93890 4.93.900 493.910 493920 3 3 'v o� � Map Scale: 1:627 if printed on A landscape (11" x 8.5") sheet. '" v ° N Meters ° � 0 5 10 20 30 � � � 0 30 60 120 180 Map projection: Web Mercator Comer coortlinates: WGS84 Edge ti6: UTM Zone 13N WCtS84 USDn Natural Resources Web Soil Survey 4/19/2024 � Conservation Service National Cooperative Soil Survey Page 1 of 3 493800 493810 493820 493830 49.3840 4.93850 4�.�38fi0 493870 493880 49.'3890 493900 493910 4.93.920 Soil Map—Larimer County Area, Colorado Appendix C MAPLEGEND Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons ,�-;. Soil Map Unit Lines 0 Soil Map Unit Points Special Point Features V Blowout Borrow Pit tt Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow _ Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot _ Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot = Spoil Area Stony Spot Very Stony Spot Wet Spot Other . Special Line Features Water Features Streams and Canals Transportation .+. Rails �.,,i Interstate Highways US Routes Major Roads Local Roads Background � Aerial Photography MAP INFORMATION The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) Iisted below. Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 18, Aug 24, 2023 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jul 2, 2021—Aug 25, 2021 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. USDn Natural Resources Web Soil Survey 4/19/2024 � Conservation Service National Cooperative Soil Survey Page 2 of 3 Soil Map—Larimer County Area, Colorado Map Unit Legend Appendix C Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 73 Nunn clay loam, 0 to 1 percent slopes � 100.0% Totals for Area of Interest USDn Natural Resources Web Soil Survey � Conservation Service National Cooperative Soil Survey 1.6 100.0% 4/19/2024 Page 3 of 3 Map Unit Description: Nunn clay loam, 0 to 1 percent slopes---Larimer County Area, Colorado Larimer County Area, Colorado 73—Nunn clay loam, 0 to 1 percent slopes Map Unit Setting National map unit symbol: 2ting Elevation: 4,100 to 5,700 feet Mean annual precipitation: 14 to 15 inches Mean annual air temperature: 48 to 52 degrees F Frost-free period: 135 to 152 days Farmland classification: Prime farmland if irrigated Map Unit Composition Nunn and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Nunn Setting Landform: Terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Pleistocene aged alluvium and/or eolian deposits Typical profile Ap - 0 to 6 inches: clay loam Bt1 - 6 to 10 inches: clay loam Bt2 - 10 to 26 inches: clay loam Btk - 26 to 31 inches: clay loam Bk1 - 31 to 47 inches: loam Bk2 - 47 to 80 inches: loam Properties and qualities Slope: 0 to 1 percent Depth to restrictive feature: More than 80 inches Drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum content.• 7 percent Maximum salinity: Nonsaline (0.1 to 1.0 mmhos/cm) Sodium adsorption ratio, maximum: 0.5 Available water supply, 0 to 60 inches: High (about 9.1 inches) Interpretive groups Land capability classification (irrigated): 3e Appendix C USDA Natural Resources Web Soil Survey 4/19/2024 � Conservation Service National Cooperative Soil Survey Page 1 of 2 Map Unit Description: Nunn clay loam, 0 to 1 percent slopes---Larimer County Area, Colorado Land capability classification (nonirrigated): 4e Hydrologic Soil Group: C Ecological site: R067BY042C0 - Clayey Plains Hydric soil rating: No Minor Components Heldt Percent of map unit: 10 percent Landform: Terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Ecological site: R067BY042C0 - Clayey Plains Hydric soil rating: No Wages Percent of map unit: 5 percent Landform: Terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Ecological site: R067BY002C0 - Loamy Plains Hydric soil rating: No Data Source Information Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 18, Aug 24, 2023 Appendix C USDA Natural Resources Web Soil Survey 4/19/2024 � Conservation Service National Cooperative Soil Survey Page 2 of 2 Page 4 Drainage, Sediment/Erosion Control, and Stormwater Quality Report O[d Town North Third Filing; Fort Collins, Colorado Apendix D a. Runoff from the front lots of the single family lots fronting Osiander Street and included in Sub-basin A is directed to the Old Town North detention Pond. Refer to original Oid Town North Drainage Plan in Appendix N. A majority of the Old Town North Third Filing property is included in the 2009 North East College Corridor Outfall (NECCO} study. Old Town North Third Filing runoff will be conveyed to the NECCO detention Pond north of Suniga Road via storm sewer. � Project is part of N ECCO Basin 810 a. A majority of the Old Town North Third Filing site is included in NECCO Basin 810 and was modeled as a developed basin. b. NECCO implemente an area o . acres or asin 1 at 0% 4. A portion of the North East College Corridor Outfall (NECCO) improvements were constructed adjacent to Old Town North Third Filing on the south side of Suniga Road with the Aspen Heights Subdivision project to the north. a. The section of storm sewer constructed in Suniga Road to convey runoff from the south side of Suniga Road to the north side of Suniga Road is a 36" diameter RCP. The storm sewer profile included with the Aspen Heights Subdivision Utility Plans is included with this report for immediate reference. Refer to Appendix N. Reference Sheet 32 of 43 (record drawing) of the "Utility Plans for Suniga Road to Blue Spruce Drive to Redwood Street and Redwood Street from Lupine Drive to Cajetan Street" by Owen Consulting Group, Inc.; Owen Project Number: 155-1O1FC; Plans dated April 29, 2015; City Engineer approval date: OS/1$/2015; Plan revision date: 14/28/2015 (As-Built storm). ,� b. The existing NECCO 36" RCP storm sewer is currently bulkheaded at bath ends with no outfall. Suniga Street existing inlets accept storm runoff and snowmelt runoff to this section of storm sewer with no outfall. There:Fore, the NECCO 36" RCP storm sewer acts as a temporary storage facility. There is approximately 960 LF of existing NECCO 36" RCP storm sewer according to Sheet 32 of 43 (record drawing} of the "U#ility Plans for Suniga Road to Blue Spruce Drive to Redwood Street and Redwood Street from Lupine Drive to Cajetan Street". � c. T`he NECCO Regional Detention Pond on the north side of Suniga Road is not complete. It is currently built to accommodate Aspen Heights Subdivision in an interim condition. Our understanding is that the NECCO regional Pond and outfall will be completed in 2 to 4 years. N"� �� l�-� � �.. .��� C :� � ��/ Page 6 Drainage, Sediment/Erosion Control, and Stormwater Quality Report Old Town North Third Filing; Fort Collins, Colorado Q c. a. L:� c Apendix D Refer to Aspen Heights Offsite Streets Sheet 30 of 43: Swale Plan and Profile included in Appendix IV. Refer to Aspen Heights Offsite Streets Sheet 31 af 43: Swale Plan and Two {2) 14"x23" elliptical RCP culverts were placed under Blondel Street and a channel was constructed on the Old Town north property with Aspen Heights construction. Our understanding is ihat the cutverts and channel were constructed to convey interim historic flows from the west to Dry Creek and the Lake Canal. Our understanding is that these flows are eliminated when the NECCO improvements are completed. The two (2) 14"x23" elliptical RCP culverts convey a 10-year storm flow of 20.8 cfs. � The 50-year starm flow to this point is 35.8 cfs. The 100-year starm peak flow is 46.8 cfs. d. Refer to Appendix for April 27, 2015 e-mail from Larry Owen to Michael Palizzi provided by Mr. Larry Owen discussing the Blondel Street culvert ,.,._,.,,:,.. ,.�a :�,�..:..,. �,.,.i� �t�..,., : 4. After deveiopment of Aspen Heights Subdi Culverts no longer ga Road and Redwood Street, and the construction of reaUli'ed. Id Town North property with the Aspen Heights Su historic flows from the west, runoff from a majority rd Filing site has no outfall. The channel berm was bu rades on the east and darnmed the historic outfall poi a. Refer to Topographical Survey for Nortl� by Intermill Land Surveying. IV. DRAINAGE DESIGN CRITERIA A. Regulations ld Town 1. Stormwater management innprovements are designed in compliance with the requirements of the City of Fort Collins Stormwater Criteria Manual adopted December 201 l. (Manual). The Manual incorporates most of the Urban Storm Drainage Criteria Manual (USDCM} with amendments that are unique to Fort Collins. � . 2. The latest versions of the USDCM software were used for runoff calculations. � ;�� ' �, � � � �• Apendix D c> i r., �� � � � , , �v - ---- � � _ '_ — . _� — �y���� — _ - s�_�. 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A NO-RlSE CERT1FlCA1'!ON 1S EtEQUIItED PRIOR TO BEOINNING ANY WC?RK WITHIN Tti� fiLoo�wAY. r tITLE M. TER DRAIlr'AGE PI.AN 4LD TOWN NORTH THIRD FILING FORT COLLINS, COLORA.DO APPRaVED• Citt E'�Cn.EEq �A�� CHECKED BY�__ 'NA'ER .k WASTEN�iER ! �1iUTY CA'i CHfCKED BY� Si�RMNA1fR JTI_�'Y CA.'� CHECKED BY: _ P�}fi5 AVO RE�REJ�':�h pAiE CHECKfO 8Y:____ iFL�F�iC EhGINFER G+1T_ CNfCK£D BY• .iG•IT Ati� iONER C+17E � CHECKED BY• E'IVIH.^,tiMENiA� PUNNEIi GA'E � rh.,. pt.a. a..y b..n n..t.�ed b� e6e ete� ol rore cn1llns � tor aonoept oal� Ths ro►taw doq no! 1my� nipo�dWllty b� � J6• nH�win` depart�o�nt, tb� pt� ol �ort Colllas E�/a�ar, or t6s Clt� ol llort Co11/nr lar �oour�a� and oorrsotnur ol Ws oalouletlons. 1�ltt6ermors, t6• tsHss do�I aot 1mp1� tb�t quantltl�s ol Itemi oa th• piaa� ary tb• flaa! quaatltlu r�qulr�d. Th• r�*t�w sh�l! not b� 000itrv�d ln an� r�ason es oaosplaaes ol 1'lnand�l r^aipondbllft� b� tbs pt� of Par! ColllAa lor addltlona! quaat/tles ol ltems erbown t,6�t mq b� nqulnd Qttrtn� t1�� coaitruetlon phaH. n� PROJECT N0. SHE�" NU, N�. oF SHEETS 2886-01-15 19 27 Appendix E Table 3.2-2. Surface Type - Runoff Coefficients Surface Type Runoff Coefficients Hardscape or Hard Surface Asphalt, Concrete 0.95 Rooftop 0.95 Recycled Asphalt 0.80 Gravel 0.50 Pavers 0.50 Landscape or Pervious Surface Lawns, Sandy Soil, Flat Slope < 2% 0.10 Lawns, Sandy Soil, Avg Slope 2-7% 0.15 Lawns, Sandy Soil, Steep Slope >7% 0.20 Lawns, Clayey Soil, Flat Slope < 2% 0.20 Lawns, Clayey Soil, Avg Slope 2-7% 0.25 Lawns, Clayey Soil, Steep Slope >7% 0.35 3.2.1 Composite Runoff Coefficients Drainage sub-basins are frequently composed of land that has multiple surface types or zoning classifications. In such cases a composite runoff coefficient must be calculated for any given drainage sub-basin. The composite runoff coefficient is obtained using the following formula: „ � (c;xA; ) C = '-' A, Where: C= Composite Runoff Coefficient C; = Runoff Coefficient for Specific Area (A;), dimensionless A; = Area of Surface with Runoff Coefficient of C;, acres or square feet n= Number of different surfaces to be considered At= Total Area over which C is applicable, acres or square feet 3.2.2 Runoff Coefficient Frequency Adjustment Factor Equation 5-2 The runoff coefficients provided in Table 3.2-1 and Table 3.2-2 are appropriate for use with the 2-year storm event. For any analysis of storms with higher intensities, an adjustment of the runoff coefficient is required due to the lessening amount of infiltration, depression retention, evapotranspiration and other losses that have a proportionally smaller effect on high-intensity storm runoff. This adjustment is Appendix E TJ C Project Date Ellie 4/8/2024 "C" CALCULATIONS PAVEMENT ROOFS GRAVEL LANDSCAPE/UNDEVELOPED 0.95 0.95 0.50 0.15 2-7% OVERALL PAVEMENT GRAVEL BASIN (ACRE) OVERALL (SF) (SF) (SF) ROOFS (SF) LANDSCAPE (SF) 2 YR C 100 YR C H1 0.81 35,197 - - - 35,197 0.15 0.18 Site Total 0.81 35,197 - - - 35,197 0.15 0.18 OVERALL PAVEMENT GRAVEL BASIN (ACRE) OVERALL (SF) (SF) (SF) ROOFS (SF) LANDSCAPE (SF) 2 YR C 100 YR C A 0.16 7,130 3,445 - 1,054 2,631 0.65 0.79 B 0.47 20,348 6,146 - 13,404 798 0.92 1.00 C 0.11 4,932 1,105 - - 3,827 0.33 0.40 D 0.06 2,787 900 - - 1,887 0.41 0.49 Site Total 0.81 35,197 11,596 - 14,458 9,143 0.74 0.89 Total Imperviouss Area Added 26,054 SFT Min Area Treated (75% for RG) 19,541 SFT ActualArea Treated 19,550 SFT OKAY! T:\Projects\Ellie\03_Project Reports\Drainage\Calcs\C Calcx - C-CALCS 6/18/2024 Appendix E TJC Project Ellie Date: 6/18/2024 TIME OF CONCENTRATION - DEVELOPED t; = 1.87(1.1 - CS)�L / So.33 MANUAL Eqn. (33-2) V= 1.49/n R2�351�Z MANUAL Eqn. (5-4) tt = L/(60V ) MAN UAL Eqn. (5-5) t� = t; + tt MANUAL Eqn. (5-3) MAX. t� = L/180+ 10 MANUAL Eqn. (3.3-5) SUB-BASIN DATA INITIAL / OVERLAND TRAVEL TIME (Tt) COMP Tc CHECK FINAL REMARKS AVG. SLOPE Tc (Urbanized Basins) Tc Design Point BASIN(5) AREA C LENGTH AVG. SLOPE Ti LENGTH S n R VEL Tt TOTAL Tc=(L/180)+10 (Acres) (%) (ft/ft) (fps) (min) LENGTH (ft) (min) (min) H1 H1 0.81 0.15 300 2.0 24.48 0.0 0.0 24.48 300 11.7 11.7 1 A 0.16 0.65 45 4.0 3.53 76 0.01 0.12 0.50 0.8 1.6 5.15 121 10.7 5.2 2 B 0.47 0.92 45 2.0 1.81 214 0.008 0.12 1.00 1.1 3.2 5.02 259 11.4 5.0 3 C 0.11 0.33 15 2.0 4.44 200 0.01 0.12 0.50 0.8 4.3 8.70 215 11.2 8.7 4 D 0.06 0.41 12 4.0 2.84 200 0.01 0.12 0.50 0.8 4.3 7.10 212 11.2 7.1 L\Projects\Ellie\03_Project Reports\�rainage\Calcs\C Calcx - CONC. TIME 6/18/2024 Appendix E Table 3.4-1. IDF Table for Rational Method Duration Intensity Intensity Intensity (min) 2'Year 10-year 100-year (in/hr) (in/hr) (in/hr) 5 2.85 4.87 9.95 6 2.67 4.56 9.31 7 2.52 4.31 8.80 8 2.40 4.10 8.38 9 2.30 3.93 8.03 10 2.21 3.78 7.72 11 2.13 3.63 7.42 12 2.05 3.50 7.16 13 1.98 3.39 6.92 14 1.92 3.29 6.71 15 1.87 3.19 6.52 16 1.81 3.08 6.30 17 1.75 2.99 6.10 18 1.70 2.90 5.92 19 1.65 2.82 5.75 20 1.61 2.74 5.60 21 1.56 2.67 5.46 22 1.53 2.61 5.32 23 1.49 2.55 5.20 24 1.46 2.49 5.09 25 1.43 2.44 4.98 26 1.4 2.39 4.87 27 1.37 2.34 4.78 28 1.34 2.29 4.69 29 1.32 2.25 4.60 30 1.30 2.21 4.52 31 1.27 2.16 4.42 32 1.24 2.12 4.33 33 1.22 2.08 4.24 34 1.19 2.04 4.16 35 1.17 2.00 4.08 36 1.15 1.96 4.01 37 1.16 1.93 3.93 38 1.11 1.89 3.87 Duration Intensity Intensity Intensity (min) 2'Year 10-year 100-year (in/hr) (in/hr) (in/hr) 39 1.09 1.86 3.8 40 1.07 1.83 3.74 41 1.05 1.80 3.68 42 1.04 1.77 3.62 43 1.02 1.74 3.56 44 1.01 1.72 3.51 45 0.99 1.69 3.46 46 0.98 1.67 3.41 47 0.96 1.64 3.36 48 0.95 1.62 3.31 49 0.94 1.6 3.27 50 0.92 1.58 3.23 51 0.91 1.56 3.18 52 0.9 1.54 3.14 53 0.89 1.52 3.10 54 0.88 1.50 3.07 55 0.87 1.48 3.03 56 0.86 1.47 2.99 57 0.85 1.45 2.96 58 0.84 1.43 2.92 59 0.83 1.42 2.89 60 0.82 1.4 2.86 65 0.78 1.32 2.71 70 0.73 1.25 2.59 75 0.70 1.19 2.48 80 0.66 1.14 2.38 85 0.64 1.09 2.29 90 0.61 1.05 2.21 95 0.58 1.01 2.13 100 0.56 0.97 2.06 105 0.54 0.94 2.00 110 0.52 0.91 1.94 115 0.51 0.88 1.88 120 0.49 0.86 1.84 TJC Project Ellie Date: 6/18/2024 2-YEAR DESIGN POINT H1 1 2 3 4 BASIN(5) H1 A B C D AREA RUNOFF tc aCRES) COEFF (MIN 0.81 0.15 11.7 0.16 0.65 5.2 0.47 0.92 5.0 0.11 0.33 8.7 0.06 0.41 7.1 DIRECT RUNOFF INTENSITI� RUNOFF tc C*A (IN/HR) (CFS) (MII 0.12 2.13 0.26 0.11 2.85 031 0.43 2.85 1.22 0.04 2.30 0.09 0.03 2.52 0.07 Appendix E TOTAL RUNOFF TRAVEL TIME SUM INTENSITY RUNOFF DESIGN SLOPE PIPE LENGTH VEL Tt Tc C*A (IN/HR) (CFS) Q (%) SIZE (FT) (FPS) (MIN) (Mlf REMARKS T:\Projects\Ellie\03_ProjectReports\Drainage\Calcs\C Calcx-2-Yr 6/18/2024 TJC Project Ellie Date: 6/18/2024 100-YEAR DESIGN POINT H1 1 2 3 4 BASIN(5) H1 A B C D AREA RUNOFF tc aCRES) COEFF (MIN 0.81 0.18 11.7 0.16 0.79 5.2 0.47 1.00 5.0 0.11 0.40 8.7 0.06 0.49 7.1 DIRECT RUNOFF INTENSITI� RUNOFF tc C*A (IN/HR) (CFS) (MII 0.15 7.42 1.08 0.13 9.95 1.28 0.47 9.95 4.65 0.04 8.03 0.36 0.03 8.80 0.28 Appendix E TOTAL RUNOFF TRAVEL TIME SUM INTENSITY RUNOFF DESIGN SLOPE PIPE LENGTH VEL Tt Tc C*A (IN/HR) (CFS) Q (%) SIZE (FT) (FPS) (MIN) (Mlf REMARKS T:\Projects\Ellie\03_Project Reports\Drainage\Calcs\C Calcx - 100-Vr 6/18/2024 Appendix E Design Procedure Form: Rain Garden (RG) UD-BMP (Version 3.07, March 2018) Sheet 1 of 2 Designer: Jim Allen Company: TJC Date: April 19, 2024 Project: Ellie Location: E Sungia & Blondel 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, la la = 100.0 % (100 % if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = la/100) i= 1.000 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.40 watershed inches (WQCV=0.8`(0.91*i3-1.19*i2+0.78*i) D) Contributing Watershed Area (including rain garden area) Area = 19,541 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWo�� = 651 cu ft Vol = (WQCV / 12)' Area F) For Watersheds Outside of the Denver Region, Depth of ds =� in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWQcvorneR =�cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VwQcvuseR =�cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum) DWo�� = 12 in B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z= 4.00 ft/ ft (Use "0" if rain garden has vertical walls) C) Mimimum Flat Surface Area AM;,, = 391 sq ft D) Actual Flat Surface Area AA�t„ai = 706 sq ft E) Area at Design Depth (Top Surface Area) ATOP = 706 sq ft F) Rain Garden Total Volume VT= 706 cu ft (Vr= ��%�rov + An�mai) / 2) ` Depth) Choose One 3. Growing Media Q 18" Rain Garden Growing Media Q Other (Explain): 4. Underdrain System Choose One QQ YES A) Are underdrains provided? Q NO B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y= 2.5 ft Valume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vo1�2= 651 cu ft iii) Orifice Diameter, 3/8" Minimum Do = 9/16 in Ellie RG Size, RG 4/19/2024, 12:11 PM Appendix E Design Procedure Form: Rain Garden (RG) Sheet 2 of 2 Designer: Jim Allen Company: TJC Date: April 19, 2024 Project: Ellie Location: E Sungia & Blondel 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric Choose One QQ YES A) Is an impermeable liner provided due to proximity � NO of structures or groundwater contamination? PROVIDE A 30 MIL (MIN) PVC LINER WITH CDOT CLASS B GEOTEXTILE ABOVE IT. USE THE SAME GEOTEXTILE BELOW THE LINER If THE SUBGRADE IS ANGULAR 6. Inlet / Outlet Control Choose One Q Sheet Flow- No Energy Dissipation Required A) Inlet Control QQ Concentrated Flow- Energy Dissipation Provided Choose One 7. Vegetation Q Seed (Plan for frequent weed control) Q 7lantings Q Sand Grown or Other High Infiltration Sod 8. Irrigation Choose One Q YES A) Will the rain garden be irrigated? � NO Notes: Ellie RG Size, RG 4/19/2024, 12:11 PM l/ersion 4.00 (May Project: Ellie TH Pipe ID: x�sting T� _� � � _ - i=r '3' - y _ � _� `1 rlaw ��e � ,�rw� �r ll Pipe Invert Slope Pipe Manning's n-value Pipe Diameter Design discharge Full-flow area Full-flow wetted perimeter Half Central Angle Full-flow capacity Half Central Angle (0<Theta<3.14) Flow area Top width Wetted perimeter Flow depth Flow velocity Discharge Percent of Full Flow Normal Depth Froude Number Half Central Angle (0<Theta-c<3.14) Critical flow area Critical top width Critical flow depth Critical flow velocity Critical Depth Froude Number Capacity check for rain garden outfall through existing 18" RCP. So = 0.0020 ft/ft n = 0.0130 D = 18.00 inches Q = 4.65 cfs Af = 1.77 sq ft Pf = 4.71 ft Theta = 3.14 radians Qf = 4.71 cfs Theta = 2.24 radians An = 1.53 sq ft Tn = 1.18 ft Pn = 3.35 ft Yn = 1.21 ft Vn = 3.04 fps Qn = 4.65 cfs Flow = 98.7% of full fiow Fr„ = 0.47 subcritical Theta-c = 1.68 radians Ac = 1.00 sq ft Tc = 1.49 ft Yc = 0.83 ft Vc = 4.65 fps Fr� = 1.00 MHFD-Culvert_v4.0, Pipe 6/18/2024, 4:05 PM LEGEND EXISTING 1' CONTOUR � � �� PROPOSED 1' CONTOUR 5730 OVERLAND FLOW -► EMERGENCY OVERFLOW PATH BASIN BOUNDARY � � � HIGH POINT � LOW POINT � RAIN WATER LEADER � EAST SUNIGA ROAD (115' ROIN) S7 � Sf EX STM MH RIM: 4970.04' 36" RCP INV. (W): 4957.52' 36" RCP INV. (E): 4957.31' 4" PVC INV. (N): 4965.08' EX STM M H RIM: 4968.28' 24" RCP INV. (S): 4958.05' 36" RCP INV. (W): 4957.08' 36" RCP INV. (E): 4957.05' JT 1 y � EX VERTICAL CURB � EX STORM INLET .- � - �- - - - - - - _ � � � z -- �_ - - v - —�•� - �, �� . . . .. . _ W . � � • :.... �� , . � —� — --_— -- - .. . � o �, � . • � � � � — — . . .. � . : . � ._ : : ' J . . . . .' � . . . . � . . . . . . . . . . . . . .. . .. . . . . . . . . . . .. . . . . . , . . . • • '. . .�. . . . . . . �. . . . � . . . , ,. . . ��� - [1J - . . . . . . , . . . . . . , . - . . . .. . . . . .� . .. . . . . . . � .. . . . . . . . . . : ' �.� . . , . . . . . . . . . . � . . . . .. . �; � �� �-o � ���. , .• �- q �y Y��V �� � � 1- U� . . • . , . . . _ . . . . . . . , . . . . . -' ' � . • � ' . . . . � . . . .'. � . . . . . . . Q�--,____.._-��-_.�-� �. . 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" I � --. ... - 18" RC ALLEY (12' WIDE) � _ - , � � ` �_ I P H � �� �\ H � j y ��� INV W: 4965.95' _ — --- -- � � _�a , 15 � ��.. , ��— sT — - s --- s sfi�—�� — INV E: 49.65.76 ;� — R= 1 9. W �—�... 8 5 __ �' o.s� • � � I > , 11G� �� � � , .18 � �; . >� --. � - -� sT I---- . � — sr � �; I _� �,, _ �=90°00 00' ,_ CH=26.87' ;,� � _ �� p � I CB=S 44°21'S8" E I � o �� � � \ -- .� � --- .� - � � � -- - 18" RCP �n ` // � � 9 � � � � � _ � INV W: 4965.90' �, o r ( � ss� ---� �96j w � I NV E: 49.65.77' � EX GUTTER PAN ' 3 � �� / � � \ � � �, ;� � o � � \ ' � ... � \ � \ \ � ',��, I r-� o }- � � �\ \�. % \�� \\ � i z �' � ' � � � � ��3. o' �► +' � � � � � UTI'CIT`(&A CESS 1� �`�6'6\ �� \\ EAS�MENT/ R=15.00 L=23. 2 � � GAf�AG� 8c 4=89°28' 16,, �-—-___ e, '` � F ENCE� S TBACK CH=21.12' � � : > � CB=S 44°06'06" E � . t i � � I � U� l I : S 88°50' 14" E 264.49' 3 . .,� c, �� �Q� l j : � 3 �.T �_� _ � _ `_ _ � 8.0' UTILITY&ACCESS EASEMENT/ — ; — ��i -',_ � _ � . . _' . _ _ _�� .� ,�_` — `!� _=.�. � i � � � 3 � � GARAGE & FENCE SETBACK ..� - �- �, � - . � � � . _ � � ,; � - , ,. . a - w �- , - v, �-- w l . _ ��,� � ,h � j ,�� ��.� , � ,� � ; � � �� i� �' �( � \ EX VERTICAL CURB T- D / M-13 . ` M 14 M=15 M-16' M 17 : .' M-�8 � M:=19 � M-20 �� � " I I I I �;, `I I� � � ` I I I EX GU�TER PAN � J� � uc �� � � / �� _ � � � , ,_` � I � � � � �, , � � � RUNOFF SUMMARY I � , 20 10 'I' 0 20 40 � � ,, i I� SCALE: 1"= 20' „ � � DESIGN POINT BASIN AREA 2 YR CxCf 2 YR RUNOFF 100 YR CxCf 100 YR RUNOFF II (ACRES j (CFS j (CFS ) g � H1 H1 0.81 0.15 0.26 0.18 1.08 I i� BAS I N DESIGNATION A 2 YR RUNOFF COEFFICIENT �.2 �a 100 YR RUNOFF COEFFICIENT BASIN AREA (ACRES) HISTORIC DRAINAGE MAP 1 � 0 Q a E Z � 0 T J 3 � � a � � � �a 0 / 0 0 ¢ U � � O / N W � U N O d H a � � a � 0 � � N O N � � � � � 0 � LEGEND EXISTING 1' CONTOUR � i _�0 PROPOSED 1' CONTOUR 5730 OVERLAND FLOW -► EMERGENCY OVERFLOW PATH BASIN BOUNDARY � � � HIGH POINT � LOW POINT � RAIN WATER LEADER � EAST SUNIGA ROAD (115' ROVI� y ;� � � � EX STM M H RIM: 4970.04' 36" RCP INV. (W): 4957.52' 36" RCP INV. (E): 4957.31' 4" PVC INV. (N): 4965.08' �v cTnn ��u 24" RCP INV 36" RCP INV 36" RCP INV EX VERTICAL CURB � EX STORM JT 1 � � - , �- _ _ _ _ _ -- : .� . � � � . ... _ W . -- �_ -. - - - -s�� � _ �, �� e :.... �� � . . � -� . --_- -- - � o �, .. . . . � . - - . � .. ... � . : . � ._ : : ' J . . . . � . . . � . . . . . . . . . . . . .. . . . . . _ . . . . . . . . . . . , .' � .�. . . . ., . . . . ': , . Li� - [iJ . . ., . .. . . . . , . � � � � _ � . ' �� �97U � - - . .. . .. .. . . . . . . � . . � � v, . . .. . . . . . . . :. . . . - . . : , . . . . .. � �. � � �..� � � Q �--,-_.._-��-_.� . . .: . _� : ��� . � . . . - --�-G�.� ..: w= � G.. � _ - - . _- �_ . . �_� - _ _ - -----��,. _ F � _ , �� � _'_.4971---- -'� .�„�� � � _ _ _� -- - - - � - - . 14.14 , __ „ �,.� � --,� --��� �- � ��� �- ���, �� � -- �... � - - - -_ �. , �. s� sr ,T -� sr _ �� __ _, . ,, - �u - _ ;; e 50 � �. .,T � __ �-� - �- _ _ �_ ,, ` `49%Q � ' �7 �,; 1 �-.. - � , �. - � ' � � - -- _, � -- .a � � ; - : , � si .�� ., � - ,.a � - � _ - - - - � - _ R 9 00' L ' �_ �; S, -� ,: s;, -. ; � AS90°00-QO" �; s� s� , i-- N 89°21 58" W 324.54� y 3 - �-�. --- �.� _ �`� 2.�' � 4971 I I 497� 4970 CB=f�� 4°21'S8" W � � � �i C � � Lot M1 OUTFALL CURB ;:� o.� �•4 Ir- 0 3 � � _ N � _ _ - - - II � r O �d' I � __� '��� F=72.0 FF=72.0 FF=72.00 FF=72.00 FF=72.00 FF=71.83 FF=71.83 FF=71.83 FF=71.83 � FF=71.33 FF=71.33 FF=71.33 i FF=71I.33 � a 1 ��� ' � E VERTI AL CURB o�.,-, ---�... o � �!� o j � , DRAINAGE EASEMENT - - � .. p_ _ . cn � � � �� S 89°21 '58" E �5.21 '.: I A ^ � � I , I � ', , � � � /1 � � _ „ ALLEY (12 WIDE) � _ 1 1 II 1 � �, ,� `� � 18 R C P � - , 1 1 / / W W �I , � INV W: 4965.95' � _ F=70.2 F=71.2 F=71.4 =71.2 = =7 .9 =70.8 �-G =7 .6 F=7 .5 F=70.3 � �-GF'=7 2 1 �-G =70.1 � F=69.9 !�� � - - _ � � B , .� . . � \ _ - __ � � R=19.U� L=29.85 __ � �.� - -` 0.47 .92 _ .. �, � � � INV E. 49.65J6 ,� �� _ _ _ _ . _ - - „ l �i �<, �.. s o ! 1.0 . . . . _ � i - - s4 . s i � _ � <.� -.. s i e sT le S i �=90°00'00 _ . _ �� � - ' _ � c- 1...:. W � < CH-26.87 � �.... .. d-.. 49�...... � .:..:...... ........:.. � P � CB=S 44°21'S8" E I� � /� � 9 � _ W�' W � � 18" RCP � �� _ �. �. � INV W: 4965.90' .65 � � � 0 0. 1 6 �9 _. .. � I N V E: 4 9. 6 5. 7 7 - . � � r E X G U n E R P A N 3 I� _ '� W�' W I N �� OPENING � o� F= 7 . 2 F= 7 1. 2 F=71.4 F=71.2 � F=71.1 F=70.9 F=70.8 F=70.6 F=70.5 F= 7 0. 3 F= 7 0. 2 G F= 7 0. 1 F=69.9 �' "' � � v �...... .. � 1 � � � � � �. o � �Y W .. .. � ... O �. ..�.'I I I �' v �Y ......... z _ i. OUTFALL CURB � 1, cn.:::::: ::::: � 1� o � ;8. o �' � �T�'Cln&A D ' EASEME - - _ _- -_ _- -_ _ d R=15.00' L=23. 2' � - - ' AGf , „ _. ... - - il 0.06 .49 I � �FENCE . _ _ _ FF-71.66 FF-72.00 FF-72.00 FF-72.00 FF-72.00 FF-72.00 FF-72.00 FF-71.33 FF=71.33 FF-70.66 FF-70.66 FF-7 .66 4� GAR SE 4=89 28 16 _ ..._____ . _ .. _ � _-. _ CH=21.12' _ _ 4970 4970' ���_ _ �_, _ CB=S 44°06'06" E � 1 _ � S 88°50 14" E 4. ' ,. 4� � � OIJTFALL CUR , _� ,�..�.,� �, 2 ��� l . --___ �--� -� � � ---- � � � ��� OUTfALL CUR � I � 8.0' UTILITY&ACCESS EASEMENT/ � - ��� -�� - : -'-�- - - -- - �:�- - � ;� � � ; .. � �. . � ,. GARAGE & FENCE SEfBACK � _ . ' � a� - � \` ��, � vd �- - ':�� - - �ra - - - � - � � � � , �� u . : i ; �- �.. :. / � �� ( � . . .. . . � �� ,�. �.� . ._ �7 � , , '�� - �� � ' �\ EX VERTICAL CURB T- D / M-13 . `:.M 14 M=.15 M-16 M-17 M-�B M.-1g � M-20 ��, , s; ` I I I I �, \`s , � � �`� I ' I EX GU�TER PAN � �� � uc �� �,;�� ; ` �� I I I I j II I ` I � � I � ` I I I I �i � � � � � G�l���•`��]�uI�I�Ti��� DESIGN POINT BASIN AREA 2 YR CxCf 2 YR RUNOFF 100 YR CxCf 100 YR RUNOFF (ACRES) (CFS} (CFS) 1 A 0.16 0.65 0.31 �. 79 1.28 2 B a.47 0.92 1.22 1.�0 4.65 3 C 0.11 0.33 0.09 0.40 0.36 4 D 0. 06 0.41 0. 07 0.49 0.28 � BAS I N DESIGNATION A 2 YR RUNOFF COEFFICIENT �.2 �a 100 YR RUNOFF COEFFICIENT BASIN AREA (ACRES) 20 10 �Ij 0 20 40 � ��I SCALE: 1 " = 20' ,� <<:�� li I; i «;_ lll UTILITY PLANS FOR THE ELLIE AT OLD TOWN TJC LIMITED 8751 E HAMPDEN AVE SUITE B10 DENVER, CO 80231 303.840.4742 www. tjcivil. com � � r U � O Q � � 2~ O ~ Q � J Z o�Wo a z �=V � z�~� w ��pz C� O- � Q � � � � Z � � � V Q � Q � � W � ~ ~ � L � a � � Q W WZT J C� � z z � � L.L.I ? � z O wOvJ� � ~ W O D�U O z � 0 � w Q U O J �� ;; �� � N �� � � DESIGNED BY: JWA CHECKED BY: TBM PROJECT N0. 2336 SHEET OF 6 6