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HomeMy WebLinkAboutTOWNHOMES AT TIMBER CREEK PUD - PRELIMINARY - 16-89N - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTPRELIMINARY DRAINAGE REPORT THE TOWNHOMES AT TIMBER CREEK Prepared for: KEM HOMES 3000 South College Avenue, Suite 103 PO Box 1845 Fort Collins, CO 80522 Prepared by: North Star Design 1200 Carousel Drive, Suite 201 Windsor, Colorado 80550 (970) 686-6939 March 26, 1999 Job Number 111-01 I S North Star 1 Afto. design March 18 1999 Basil Hamdan City of Fort Collins Stormwater ' 700 Wood Street Fort Collins, CO 80522-0580 RE: Preliminary Drainage Report for the Townhomes at Timber Creek Dear Basil, I am pleased to submit for your review and approval, this Preliminary Drainage Report for the Townhomes at Timber Creek. I certify that this report for the preliminary drainage design of the Townhomes at Timber Creek was prepared in accordance with the criteria in the City of Fort Collins Storm Drainage Manual. I appreciate your time and consideration in reviewing this submittal. Please call if you have any questions. Sincerely, 0 EGis� .a 3 Patricia Kroetch, P. ION AL �� J 1200 Carousel Drive, Suite 201 Windsor, Colorado 80550 970-686-6939 Phone & Fax TABLE OF CONTENTS TABLEOF CONTENTS........................................................................................................... iii 1 01 k] Ll E GENERAL LOCATION AND DESCRIPTION 1.1 Location.............................................................................................................. 1 1.2 Description of Property........................................................................................ 1 DRAINAGE BASINS AND SUB -BASINS 2.1 Major Basin Description.......................................................................................1 2.2 Sub -Basin Description.......................................................................................... 1 DRAINAGE DESIGN CRITERIA 3.1 Regulations.......................................................................................................... 2 3.2 Development Criteria Reference and Constraints .................................................. 2 3.3 Hydrologic Criteria.............................................................................................. 2 3.4 Hydraulic Criteria................................................................................................. 3 DRAINAGE FACILITY DESIGN 4.1 General Concept.................................................................................................. 3 4.2 Hydrologic Analysis of the Proposed Drainage Conditions ................................... 3 4.3 Specific Flow Routing.......................................................................................... 4 4.4 Drainage Summary ............................................................................................... 5 EROSIONCONTROL.................................................................................................... 5 6. CONCLUSIONS 6.1 Compliance with Standards................................................................................. 5 6.2 Drainage Concept................................................................................................ 5 7. REFERENCES............................................................................................................... 6 APPENDICES A Vicinity Map B Hydrologic Computations C Figures and Tables D Excerpts from Previous Reports iii GENERAL LOCATION AND DESCRIPTION 1.1 Location The Townhomes at Timber Creek is a proposed 5.1 acre multi -family residential development. This project is located in the West half of Section 5, Township 6 North, Range 68 West of the Sixth Principal Meridian, in the City of Fort Collins, Larimer County, Colorado. The project is a portion of the Timber Creek P.U.D and is located in the northeast corner of the intersection of Timberline Road and Timber Creek Drive. The project is bounded on the south and east by the single-family portion of Timber Creek P.U.D., on the north by undeveloped property owned by Poudre Valley Hospital and on the west by Timberline Road. 1.2 Description of Property The entire project consists of approximately 5 acres of land. The land is currently undeveloped and slopes to the south at approximately 1 %. A drainage swale has been constructed along the north property line to divert off site flows to the east. The project will consist of 13 buildings containing 4 or 6 units each and detached garages. A private road will provide access to the site and will have some off street parking. DRAINAGE BASINS AND SUB -BASINS 2.1 Major Basin Description The proposed development lies within the McClellands Drainage Basin. Runoff from the project area currently flows overland to Timber Creek Drive and is routed to the existing Detention Pond 373 in the southeast corner of Stetson Creek P.U.D. 2.2 Sub -basin Description This site encompasses basins 202 and 203 and portions of basins 204 and 205 as delineated in the Final Drainage and Erosion Control Study for Timber Creek P.U.D. (see Appendix). The site has been graded to conform as nearly as possible to the basin delineation and runoff calculations previously completed. These basins are shown on the I F L Preliminary Grading and Drainage Plan in the back pocket of this report and a more detailed description of each basin is located in section 4.4 of this report. 3. DRAINAGE DESIGN CRITERIA 3.1 Regulations This report was prepared to meet or exceed the "City of Fort Collins Storm Drainage Design Criteria Manual" specifications. Where applicable, the criteria established in the "Urban Storm Drainage Criteria Manual" (UDFCD), 1984, developed by the Denver Regional Council of Governments, has been used. 3.2 Development Criteria Reference and Constraints The runoff from this site has been routed to conform to previous calculations completed with the Final Drainage and Erosion Control Study for Timber Creek P.U.D. First Filing by RBD Engineering Consultants dated July 1, 1994. Detention for this site is provided in the Detention Pond 373 as noted in the above mentioned report. A majority of the runoff from this site will be collected in an inlet in Timber Creek Drive and conveyed to the detention pond via storm pipe. The streets and associated drainage systems surrounding the site are existing. The existing storm system was designed by RBD Engineering and was sized to convey the additional runoff resulting from the development of this site. 3.3 Hydrologic Criteria Runoff computations were prepared for the 2-year minor and 100-year major storm frequency utilizing the rational method. ' All hydrologic calculations associated with the basins are included in the Appendix of this report. Standard Form 8 (SF-8) provides time of concentration calculations for all sub - basins. Standard Form 9 (SF-9) provides a summary of the design flows for all Sub -basins and Design Poirr:s associated with this site. ' Detention for this site is provided off site, therefore no discharge and storage calculations were performed. ' 2 1 3.4 Hydraulic Criteria ' All hydraulic calculations within this report have been prepared in accordance with the City of Fort Collins Drainage Criteria and are also included in the Appendix of this report. 1 4. DRAINAGE FACILITY DESIGN ' 4.1 General Concept The site was graded to maintain the drainage patterns dictated in the Final Drainage Report for Timber Creek P.U.D. The majority of the runoff from the site will flow to the ' south and into an inlet in Timber Creek Drive. A portion of the site will drain east to Pole Pine Lane and be conveyed via gutter flow to a sidewalk culvert in Smallwood Drive. The runoff is then conveyed in a grass swale to the detention pond. 4.2 Hydrologic Analysis of the Proposed Drainage Conditions 1 The Rational Method was used to determine both the 2-year and 100-year peak runoff ' values for each subbasin. The Rational Method utilizes the equation: ' Q = CIA (1) Where Q is the flow in cubic feet per second (cfs), A is the total area of the basin in acres, ' C is the runoff coefficient, and I is the rainfall intensity in inches per hour. "C" values were determined using Table 601 of the "City of Fort Collins Storm Drainage Criteria Manual' and I was determined from Figure 502. In order to utilize the rainfall intensity curves, the time of concentration is required. The following equation was used to determine the time of concentration. t` = tj + tt (2) where t, is the time of concentration in minutes, t; is the initial or overland flow time in ' minutes, and tt is the travel time in the channel, pipe, or gutter in minutes. The initial or overland flow time is calculated with the equation: ' t; = [1.8(1.1- C)Lo.sj/(S)0.33 (3) ' 3 d iJ G n where L is the length of overland flow in feet (limited to a maximum of 500 feet), S is the average slope of the basin in percent, and C is the runoff coefficient. Standard forms SF-8 and SF-9 provide a more detailed presentation of calculation methods. 4.3 Specific Flow Routing A summary of the drainage patterns within each basin is provided in the following paragraphs. Subbasin 201 contains the east half of Timberline Road along the site frontage and a portion of the north half of Timber Creek Drive along the frontage. Runoff from Subbasin 201 is conveyed via gutter flow to the main entry of the site and into Subbasin 204. Subbasin 202 contains the western portion of the site. Runoff from Subbasin 202 is conveyed via overland flow and swales to the interior street. The flow is then routed southwest in the street to the main entry where the runoff combines with runoff from Subbasin 201 and enters Subbasin 204. Subbasin 203 contains the eastern portion of the site. Runoff from Subbasin 203 is conveyed via overland flow and swales to the interior street. The runoff is then routed east in the street to a concrete channel that conveys the flow to Pine Pole Lane. Subbasin 204 contains a small area of the south portion of the site and 3 existing single- family lots. Runoff from Subbasin 204 is conveyed via overland flow and swales to existing side lot swales along Lots 1, 2 and 3. The runoff then flows into Timber Creek Drive, combines with flow from Subbasins 201 and 202 and into the existing inlet at design point 204. Subbasin 205 contains a small area of the southeast portion of the site and 12 existing single-family lots. Runoff from Subbasin 205 is conveyed via overland flow and swales to existing side lot swales. The runoff then flows into Timber Creek Drive and into the existing inlet at design point 205. 4 ' S. 1 1 1 ' 6. 1 1 1 1 1 4.4 Drainage Summary There were not any drainage problems encountered on this site. Proposed drainage patterns were delineated in order to minimize impact on existing housing. Basins were modified slightly from the predicted basin layout in the RBD report but total runoff from the site is within restrictions outlined in that report. The storm conveyance system is primarily a surface system and has been designed for minimum maintenance. The City of Fort Collins will be responsible for maintenance of storm drainage facilities located within the right-of-way. The drainage facilities located on this site will be maintained by the The Townhomes at Timber Creek Master Association.. EROSION CONTROL During final design for this site, appropriate measures will be designed to control erosion from the site. These measures to limit erosion will typically include installation of silt fence, reseeding and mulching all disturbed areas that will not be paved and using gravel mulch on areas that are to be paved. CONCLUSIONS 6.1 Compliance with Standards All computations that have been completed within this report are in compliance with the City of Fort Collins Erosion Control Reference Manual for Construction Sites and the Storm Drainage Design Criteria Manual. 6.2 Drainage Concept The proposed drainage concepts presented in this report and on the construction plans adequately provide for the transmission of developed on -site runoff to Timber Creek Drive or Pine Pole Lane where the runoff will be conveyed in existing facilities to the existing downstream detention facility. The onsite street capacities and off site storm drain system will provide for the 2- year and the 100- year developed flows to reach the existing detention facility. The existing detention facility has been sized to accommodate developed runoff from this site. 9 If, at the time of construction, groundwater is encountered, a Colorado Department of Health Construction Dewatering Permit would be required. 7. REFERENCES 1. City of Fort Collins, "Storm Drainage Criteria Manual", (SDCM), dated March, 1986. 2. Urban Drainage and Flood Control District, "Urban Storm Drainage Criteria Manual", Volumes 1 and 2, dated March, 1969, and Volume 3 dated September, 1992. 3. Guo, James C.Y., PhD, P.E. "Street Hydraulics and Inlets Sizing using the Computer Model UDINLET". University of Colorado at Denver, January 1995. 4. StormCAD v.1.5, Storm Sewer Design & Analysis Software by Haestad Method, 1997. 0 APPENDIX A VICINITY MAP F F I 1 1 HARMONY ROAD O O O HORSETOOTH ROAD PROJS31 CT T E CITY LIMITS COUNTY ROAD J6 FOSSIL_ CREEK RE SERA VICINITY MAP APPROXIMATE SCALE: 1" = 2000' Ll 1 APPENDIX B HYDROLOGIC COMPUTATIONS North Star Design 1200 Carousel Drive, Suite 201, Windsor, CO 80550 RUNOFF COEFFICIENTS & % IMPERVIOUS LOCATION The Towtihomes at Timber Creek PROJECT NO: 111-01 COMPUTATIONS BY: ppk DATE: 3/ 19/99 Recommended Runoff Coefficients from Table 3-3 of City of Fort Collins Design Criteria Recommended % Impervious from Urban Storm Drainage Criteria Manual Streets, parking lots (asphalt): Sidewalks (concrete): Roofs: Lawns (flat <2%, sandy soil): Runoff % coefficient Impervious C 0.95 100 0.95 96 0.95 90 0.25 0 SUBBASIN DESIGNATION TOTAL AREA (ac.) TOTAL AREA (sq.ft) ROOF AREA (sq.ft) PAVED AREA (sq.ft) SIDEWALK AREA (sqA) LANDSCAPE AREA (sq.ft) RUNOFF COEFF. (C) % Impervious 201 1.08 46,880 3,294 20,323 3,056 20,207 0.65 56 202 2.89 125,770 34,488 38,251 9,047 43,984 0.71 62 203 1.51 65,819 16,205 19,066 4,398 26,150 0.67 58 204 1.37 59,562 11,102 9,871 4,292 34,297 0.55 40 205 3.00 130,680 13,150 25,966 91,564 0.46 212 3.00 130,700 13,800 30,702 86,198 0.49 t NOTES: Easin 201 area increased slightly from RBD report but C value is less than predicted in RBD report Easin 202 was reduced by 0.09 acres and area was added to Basin 204. C value is slightly higher than RBD report predicted. Easin 205 area remains same as RBD report. C value is less than predicted Easin 212 was reduced by 0.12 acres and area was added to Basin 203. Area impervious remains the same as RBD report Equations - Calculated C coefficients & % Impervious are area weighted C=Z(CiAi) /At �Ci = runoff coefficient for specific area, Ai Ai = areas of surface with runoff coefficient of Ci n = number of different surfaces to consider At = total area over which C is applicable; the sum of all Ai's Flow.xts as as as a �■ as �a a�a �a ■a a� as is ■a as as �a �a as North Star Design 1200 Carousel Drive, Suite 201 Windsor, CO 80550 LOCATION: PROJECT NO: COMPUTATIONS BY DATE: 2-yr storm The Townliomes at Timber Creek 111-01 ppk 3/19/99 Cf = 1.00 STANDARD FORM SF-2 TIME OF CONCENTRATION - 2 YR SUB -BASIN DATA INITIAL /OVERLAND TIME (ti) TRAVEL TIME / GUTTER OR CHANNEL FLOW (tt) tc CHECK (URBANIZED BASIN) FINAL tc REMARKS DESIGN PONIT SUBBASIN(s) (1) Area (ac) (2) C (3) Length (ft) (4) Slope (%) (5) ti (min) (6) Length . (ft) (7) Slope (%) (8) n Manning rough. Vel (ft/s) (9) it (min) (10) tc = ti + tt (11) Total L (It) (12) tc=(1/180)+10 (min) (13) (min) (14) 201 201 1 08 065 40 2.0 411 600 20 0 016 2.8 352 76 640 13.6 7.6 202 202 289 0.71 120 20 621 403 0.5 0,016 14 4 73 109 523 12.9 10.9 203 203 1 51 067 120 20 67 315 05 0 016 1.4 369 104 6591 13.7 10A 204 204 1 37 055 189 20 109 224 055 0.016 1.5 2.51 13A 803 14.5 13A 205 205 300 0.46 180 2.0 117 390 055 0 016 16 406 158 1070 159 158 212 212 360 049 130 20 102 500 0.6 0.016 16 5.20 15A 630 154 EQUATIONS: tc=III +tt ti=11.87(1.1-CC,)L051/S'/3 tt = LfVel Velocity from Manning's Eqquation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual) final tc = minimum of ti + tt and urbanized basin check min. tc = 5 min. due to limits of IDF curves Flow As TOC-2 rr +�■ r r� rr it � r �r North Star Design 1200 Carousel Drive, Suite 201 Windsor, CO 80550 LOCATION: PROJECT NO: COMPUTATIONS BY DATE: 100-yr storm The Townhomes at Timber Creek 111-01 ppk 3/19/99 Cf = 1.25 STANDARD FORM SF-2 TIME OF CONCENTRATION - 100 YR SUB -BASIN DATA INITIAL /OVERLAND TIME (ti) 1 RAVEL TIME / GUTTER OR CHANNEL FLOW (tt) tc CHECK (URBANIZED BASIN) FINAL tc REMARKS DESIGN PONIT SUBBASIN(s) (1) Area (ac) (2) C (3) C'Cf Length (ft) (4) Slope (%) (5) ti (min) (6) Length IN (7) Slope (%) (8) n Manning rough Vel (ft/s) (9) It (min) (10) tc = ti + It It 1) Total L (ft) (12) tc=(I/180)+10 (min) (13) (min) (14) 201 201 1 08 0.65 0.81 40 20 26 600 2 0.016 2.8 3.52 6.1 640 13.6 6 1 202 202 289 0.71 0.88 120 20 34 403 0.5 0 016 1 A 4731 8.1 5231 12.9 8 1 203 203 1.51 0.67 0.84 120 20 41 315 0.5 0.016 14 369 T8 659 13.7 7 8 204 204 1.37 0.55 068 189 2.0 8.2 224 055 0.016 1 5 2.51 10.7 803 14.5 107 205 205 3.00 0.46 0.57 180 2.0 92 390 0.55 0.016 1 5 4 10 13.3 1070 159 133 212 212 300 0.49 0.61 130 20 80 500 0.6 0.016 1 6 5.20 132 630 13.5 132 EQUATIONS: tc=ti+tt ti=[1.87(1.1-CCt)L05]/S"' tt = L/Vel. Velocity from Manning's Eqquation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual) final tc = minimum of ti + tt and urbanized basin check min. tc = 5 min. due to limits of OF curves Flow As TOC-100 M M M M+ r r r North Star Design 1200 Carousel Drive, Suite 201 Windsor, CO 80550 RATIONAL METHOD PEAK RUNOFF (2-YEAR) LOCATION: The Townhomes at Timber Creek PROJECT NO: 111-01 COMPUTATIONS BY: ppk DATE: 3/ 19/99 2 yr storm, Cf = 1.00 DIRECT RUNOFF CARRY OVER TOTAL REMARKS Design Point Tributary Sub -basin A (ac) C Cf tc (min) i (in/hr) Q (2) (cfs) from Design Point Q (2) (cfs) Q(2)tot (cfs) Q(2j#ot {tom} ................................ 201 201 1.08 0.65 7.6 2.82 1.97 1.97 Streetflow 202 202 2.89 0.71 10.9 2.46 5.00 5.00 >+Ei;" Into Timber Creek Drive 203 203 1.51 0.67 10.4 2.51 2.54 2.54 :: Into 2' concrete channel 204 1.37 0.55 13.4 2.24 1.68 1.68 1 d;i;i'i"Into Timber Creek Drive !22�� 205 3.00 0.46 15.8 2.07 2.86 2.86_Into Timber Creek Drive 212 3.00 0.49 15.4 2.10 3.07 3.07 328 .` > Into Pine Pole Lane Q=CrCiA Q = peak discharge (cfs) C = runoff coefficient Cr = frequency adjustment factor I = rainfall intensity (in/hr) from IDF curve I=46.7i(10+tc)07B` A = drainage area (acres) Flow.xls Q2 r r r r +rr r �► rr r r r r r rr rr rs r� r �r North Star Design 1200 Carousel Drive, Suite 201 Windsor, CO 80550 RATIONAL METHOD PEAK RUNOFF (100-YEAR) LOCATION: The Townhomes at Timber Creek PROJECT NO: 111-01 COMPUTATIONS BY: ppk DATE: 3/19/99 100 yr storm, CIF = 1.25 DIRECT RUNOFF CARRY OVER TOTAL RSR Report 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) Q000)t0t (c€s} 201 201 1.08 0.81 6.1 8.43 7.35 7.35 7.87 Street flow 202 202 2.89 0.88 8.1 7.68 19.56 19.56 Into Timber Creek Drive 203 203 1.51 0.84 7.8 7.81 9.92 9.92 3.20 Into 7 concrete channel 204 204 1.37 0.68 10.7 6.93 6.48 6.48 7.;3i Into Timber Creek Drive 205 205 3.00 0.57 1 13.3 1 6.31 10.88 10.88 12.19 Into Timber Creek Drive 212 212 3.00 0.61 13.2 6.34 11.60 1 1 11.60 12.:38 Into Pine Pole Lane Q=CiA Q = peak discharge (cfs) C = runoff coefficient I = rainfall intensity (in/hr) from IDF curve I = 75 / (10+ tc)0 ' A = drainage area (acres) Flow.xls Q100 APPENDIX C FIGURES & TABLES F 1 No Text DRAINAGE CRITERIA MANUAL RUNOFF �._ 5 0 30 I— 20 Z w U Cr. °' 10 w a O 5 W � 3 0 U 2 lr ; - W F- a 3 S loll= .1 .2 .3 ,5 1 2 3 5 10 20 VELOCITY IN FEET PER SECOND FIGURE 3-;1l. 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 1 I APPENDIX D EXCERPTS FROM PREVIOUS REPORTS 1 FINAL DRAINAGE ATMID EROSION CONTROL STUDY FOR TfMBER CREEK P.U.1). FIRST FILING FORT COLLINS, COLORADO July 1, 1994 Prepared for: Everitt Companies 3000 South College Avenue Fort Collins, Colorado 80525 Prepared by: RBD, Inc. Engineering Consultants 209 S. Meldnim Fort Collins, Colorado 80521 (303) 482-5922 RBD Job No. 035-134 D. Hydraulic Criteria All calculations within this study have been prepared in accordance with the City of Fort Collins Storm Drainage Criteria. E. Variances from Criteria Due to the way in which the SWMM model was originally used by RBD and then revised per the City of Fort Collins Stormwater Utility's request, detention pond number 373 is seeking a variance for the amount of water it is releasing into the McClellands Basin Drainageway. IV. DRAINAGE FACILITY DESIGN A. General Concept Developed flows for most of Timber Creek P.U.D. will be routed by an open channel to Detention Pond 373, located at the southeast corner of Stetson Creek P.U.D.. Detention volume has been provided in this pond for those areas of Timber Creek. Approximately 14.5 acres along the easterly portion of the project will be routed to pond 374, and detained in that pond. B. Specific Details Approximately 100 acres north of the proposed Timber Creek development historically flows south across this project to the McClellands Drainageway. The historic flows from this property will sheet flow to a temporary interception ditch which parallels the northerly property line of Timber Creek. These historic flows will be routed south along the easterly property line of Timber Creek and Stetson Creek, and through Detention pond 373, and released into the McClellands Drainageway. As development occurs on this property, on -site detention will need to be developed. As this is a temporary interception swale only, no permanent concrete trickle channel has been designed into this swale, although the longitudinal slope is only 0.5%. Approximately 2/3 of the westerly portion of this project will be routed to and detained in Detention pond 373. Sub Basins 202 and 203 were considered as future Multi -Family. Sub Basin 201 is a portion of Timberline Road adjacent to this site, and will flow to Timber Creek Drive. A small portion of Timberline Road (Sub Basin 520*) adjacent to this site will flow south along Timberline Road to the entry to Stetson Creek, and then on to Detention Pond 373. 4 The final design of Timberline Road north of and adjacent to this site (currently being designed by Northern Engineering Co. Inc.) will include curb inlets just to the north of developed basin 201 and immediately west of the temporary drainage swale along the northerly property line. These curb inlets will intercept all developed flows from Timberline Road north of this project, and route them easterly in the temporary drainage swale north of the property, and then south to Detention Pond 373. The temporary drainage swale north of Timber Creek will stay in use until Basin 101 is developed. Approximately the easterly 1/3 of the project will be routed to and detained in pond 374. Detained flows will be released into an open channel along the easterly property line of Timber Creek and Stetson Creek, routed through Detention pond 373, and ultimately into the McClellands Drainageway. High groundwater might be encountered during construction, and an underdrain will be constructed. In addition, a Colorado Department of Health Construction Dewatering Permit will be required. SWMM Modeling In order to analyze the ultimate permanent detention ponds within the Stetson Creek and Timber Creek developments, the Urban Drainage District's SWMM routing computer model was required to be used by the City of Fort Collins Stormwater Utility. As part of the McClellands Basin Master Plan, a SWMM model was developed for this basin, but the original SWMM Model was not available from the City of Fort Collins Stormwater Utility for utilization with this project. Because the original SWMM Model was not available from the City, the upstream Oakridge development existing 10 and 100 year SWMM Models were utilized and added onto for this developments analysis. A schematic of the original Greenhorn and O'Mara and Oakridge development SWMM models are included in the Appendix. Included in the back pocket of this report is a new. SWMM Model Exhibit drawing for the area directly east of the Oakridge development to the east property line of the Stetson Creek and Timber Creek developments. The Oakridge development SWMM model was added onto for the property within the basin between the Oakridge development and the eastern property line of the Stetson Creek and Timber Creek developments, including the new proposed Harmony Crossing P.U.D. development. The Harmony Crossing P.U.D. development Final Drainage and Erosion Control Report contains information on basins and conveyance elements added onto the SWMM model between the Oakridge development and Timberline Road. 5 STANDARD FORM SF- 2 apC"_ (Z �77L- �3 ��s,�►�_ ����•�, -�S ��v� TIME OF CONCENTRATION 06-1 1 SUBDIVISION CALCULATED BY DATE ZO,93 SUB -BASIN DATA INITIAL/OVERLAND TIME (t-) TRAVEL TIME tt FINAL tc REMARK DESIG: (I) AREA Ac (2) C (3) LENGTH Ft (4) SLOPE % (5) t; Min (6) LENGTH Ft (7) SLOPE % (8) VEL. FPS (9) tt Min (10) CALCULATIONS FOR C01MPOSITE C Min I J I �`� . � b . ? v =�,�;� 1.10 3�- ¢ "'�'.1-� I • S C�. E3 I -1. S �-4 ISTO u� C� � D i n �-�sr ,�lre _ 20 ► I .off O.-]o� 2. o . L C» `.a ? .� 3 4 o.av'o,as r o.s�xo.� o -7• o O. I o S 4.4 r-�r�bn Fny 1 I •4 Z -I e o Z,o s 4-A- C) ? • � -7,o ��o o. s I .s 3.3 �u�eE �..10Lm -AtAL-y 1 o Z,D 4 ,� 3.3 7. E3 I L e ZD4- 1.31 D.E-57 Ioc:> Z.a -7.9 21CCD z.Z .31 IcD.I Zti� I cy -2 m -(>` OS :fD C).e1 O. 15c) Z I 13-3 IUD y� o, I D Z,o &, 3 IZ__7 Ic -re- 21D% D.4:�, D.7D �0 2.0 Q.Z 31S I,c� ?,o 2,0 5. ire r1L > omit omm �mhm- ft ` dv� MONO a» STANDARD FORM SF- 2 �D_=S I C=rl_ _��e.M �s sN�l TIME OF CONCENTRATION VQIOGI�i_Corc) ����� 3.Z SUBDIVISION CALCULATED BY-L-1, DATE �Z_ tr= tj+tt SUB -BASIN DATA INITIAL/OVERLAND TIME (t•) TRAVEL TIME tt FINAL c REMARK DESIG: (I) AREA Ac (2) C (3) LENGTH Ft (4) SLOPE % (5) ti Min (6) LENGTH Ft (7) SLOPE % (8) VEL. FPS (9) tt Min (10) CALCULATIONS FOR COMPOSITE C Min Zp 2.`7(o D.S3 (cao Z.o 8.s 7s� -1eL=) Z . c� o.ss 2 .9 I.�, 9_0 I-7.S 2�e. 1 ax:> 2. 0 Zcjq 2.19 p.eo I I o Z.o 9. _, �zs �,,� c�•� o.ns I I-6 -E3. 19.1 -Z I I o 2.0 -7,4 4.8 I-7.Z Icy -Ye. 2-I0 3,E5G D.eO 14-o 2.c, 10,s 95a 0,C=0 20.4 Ztie 14-0 2, 5.3 �.9 I t3. Z I cXD_te 211 1 p,eo I�5L�, Z.o 10f 44p o,ss 1-(, 4_(, 1s.s Ztie ISo Z.o 4.� 13-Z Ic��(e ZIZ 3, IZ b.Go 13o Z,o 10,2 � o. 1 130 2. o f3. D S, 2 213 D - 0-4- b, So exD Z. o (_D E)C> Z.o 5,0 �.d Ico-Y 214 3.14 D,3`i -70 2.0 5.13 S4c, 2& -7,Z 1.3� o.zs 178 o.So 3.Ia 2-re -7O 2,a -7, 7.Z 14.F3 Ic��e 5 I UHM DHAINAGE DESIGN AND TECHNICAL CRITERIA WRC ENGINEERING, INC. COMPOSITE "C" VALUES FOR TIMBER CREEK P.U.D. Prepared by: Bud CurtiaB Date: March 2, 1994 RBD, Inc. IMPERV IMPERV PERVIOUS RUNOFF BASIN AREA AREA (AC) "C" "C" COEF 204 1.31 0.33 0.95 0.25 0.43 205 3.00 0.86 0.95 0.25 0.45 206 1.65 0.57 0.95 0.25 0.49 207 0.70 208 2.76 1.09 0.95 0.25 0.53 209 2.19 0.75 0.95 0.25 0.49' 210 3.56 1.21 0.95 0.25 0.49 211 1.78 0.59 0.95 0.25 0.48 212 3.12 1.02 0.95 0.25 0.48 213 0.24 0.00 0.25 0.25 214 3.14 0.22 0.95 0.25 0.304:.. 215 2.92 0.87 0.95 0.25 0.46 216 2.94 0.98 0.95 0.25 0.48 217 0.53 0.23 0.95 0.25 0.55-:� 218 0.98 0.34 0.95 0.25 0.49 219 0.40 0.03 0.95 0.25 0.30 220 1.08 0.11 0.95 0.25 0.32 221 0.38 0.06 0.95 0.25 0.36 222 2.83 1.01 0.95 0.25 0.50 223 1.94 0.47 0.95 0.25 0.42 224 2.16 0.78 0.95 0.25 0.50 225 1.74 0.61 0.95 0.25 0.50 226 1.60 0.51 0.95 0.25 0.47 227 1.71 0.51 0.95 0.25 0.46 228 2.34 0.10 0.95 0.25 0.28 229 2.41 0.06 0.95 0.25 0.27 521 0.60 0.00 0.95 0.25 0.25 � v aw E=s l) 5 a D i L.(_. E!�) a O -�w CLIENT \ / -1= C- 1, JOB NO. iNC t PROJECT I 1 M t�t=+r v�.�,� CALCULATIONS FOR �nMP Engineering Consultants MADEBY CHECKED BY DATE SHEET OF t1 ZOz t 2.c�,3 7 i m— . NC-EN�eroi'1c�i,1. n ZA V �waY i S F 1 d� S /t_oT I M P S?J.J t Ct�S f i 1-7 , -7 44 ZLY7 33 , 34-s Zlo i Z3, aa,+ ' 1-7 zl l l Zl Z I ZZ �-7oZ +- 9 : j�o►�►TS Z(3 f Z 14 ZIP I 8-7�8 Z18.. i ZZZ f ZS, IDS 77+ F--! QT-, . . Zz3 i -70c-0 42S ZZ4 2�714- 2 + 9 i.rr s 34 STORM DRAINAGE UPI � 5� ,,. sr-e SYSTEM PRELIMINARY DESIGN DATA Flow Time c O o43t o ci F- U E C •�- _ U U r E o o Q a c� o o cr U c� o C y O X U y C w - E o E C Cn x Street Pipe Street Pipe Remarks o ►� (n E m C a. E a O cr1 O m T o d y Q U U 00 cn o N cn .� d y U 0 y y co o U O y > ,. •y y o U y > w 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 21 22 23 -7. 0.7o Z. , F30 1.04 Z , 04 1 . o4- Z. ca 14-.- Z, cam- 2.9 11.4 O. 2. 30 2 ,98 4 ,4b 4.46 O.sS -7. oZ 4.4�- I I , 4- Ob ,�O Z. 3D 4.oZ fo . l0 !� 10 0,� -7.DZ �• 10 I •� C-6 1.0+4-kC),-70 Z,98 O•bs 410M -Z -Z 10• I (3.b o.5-7 0,�4 2.50 2. l0 1.31 5.33 I.3i -7. l� 1.8-7 "7. Ib 0,-2�e O,SS i•o-z -7•o-Z 1.g7 -7, I 1 Cory) I' c 3.9(- c::-4 - > Is.B D, sl ZO5 3, CO 3.14 3,14- O.S� 7,oZ 31 14- 1.6 TeouG-L--n 4.1 r.1IQ. 1-7•7 D,,9 1.96 E>,a,,S 9.Eli3 -j•9C� F::).%2 o-5J5 %.OZ ,b 5Z 1•6 mC5 CDPrr=`.3C=4 3XO.)+i�•oc��(D.SI g33 83 QGItj S� INIT-= T d.4 14.5 2-2-1 O, D,5r3 2.10 1.75 I . C-5 9,95 1.73 II].13 // <�J 1.-73 4.7�4 O,zE) 0-SE) -7,oz -7. -7.Z I.7B 4, I •� I.Co T�dvEl--MM�� Dp z�- 4,4-�,.�. GON1pC= S.33xD,�it To aw lpJ1 �3T -IJM P l �j C-ET I �J.g b•-To 2.85 C), 4-5 10.8z 1 .2& Z. o l� S-r�-rso.s r'o,=-��' 1? U• �. 7, 0,53 2.00 Z,-7c,=, 12.93 7.93 0,ss -7.OZI- 1 0,exD 1 ,90 2.i9 2,0S (DS 0,4� 3.3e L9, I O,SZ I .90 4.95 14,b� 4.39 0,55 Uz 3.ZD ?�.Zo O, S-o9 2n,4 0.51 1.Bo g_s► 7.81 -7.a1 o.S5 -7,dz 7-81 I _� 4. bI��-r- - 13 4- e sk:L- IC=/, 4:31 I- r STORM D A INAGE SYSTEM PRELIMINARY DESIGN DATA UJOCA" Flow Time c Street Pipe Street Pipe O O A O U m - -. O © as E�rz a= N =_' 5: ` m-� r ��- `=�L�� w 0 . �- 0 a� o • a o Remarks S U d N cf! E cL E }- c) E U - Q a 0 M c O M v cn oC vy o Q U c cn o cn . � U c� b a o .`� m n CU �n P' G' � a►l,G ' C`• . 5 6 7 8 9 10 II 12 13 14 , 15 16 17 1 18 19 20 TI MBS 1 21 22 23 1,9 25 2.9Z 99,0 7Z.3 72.3 I a0 �T Z �iSTati=101 . -T E-i, -0, AL.D ►_� 5.3 0.87 8.7 1, 7 . a7 7. 87 2. O 73.z 7.37 2,9 8,9 -0.&1 -7• ,9� h,c)z la, I�3.?A- o.ss ?A 9 18.34- 1 .L S,9 0,3Z 7,6 Zs. ' 2s•oS 25.O5 ►.� 5.0 -0 7t -7,9 1.31 7.3S 7,3S O•=_-s 2419 7,35 1_ 2.2 11.1 0.Q,,D 6,9 5,33 Z9.¢Z 29,4z p,� 24,E Z9.4Z I.� S,SS�s t�lrcee�Pr� l>`1IO�TUL�r 13.3 D,64 6.?S 3.00 1Z, 19 IZ,19 0, SS 349 IZ•19 1 .� 4.1 I 15,2 U-14 fb,IO 13. 37•U' g 7_9.oS D. ✓S ��1 ,9 _ �3,05 1.6 �.19 c�s trl �ec�cr� S 12,7 p,625 b.4s I .ems b,es t,.C�S O,Gs tN l�t�ET 4.4- 19.6 0,7?S 5,3D 9.98 58.3S IZ--7 25.61 0.5S 34,9 S, O C),sle 9. 0 0,45 3.7a 3.72> 1, Co 16Z•S a,i8 Z.o IS,s O.l� 5.9� 2.7r, 10.84 ID.a o.ss 1-7.Z 0,625 5,7 2-.19 7,SD 7-So 0.4� 2-7,o 7.8cv I I.s 17,Z 0,65 5.1 4. I O.SS �4.9 18.? I •� l8.2 0.(�2� 4� 3•� 12,1 IZ.l3 0. ?4.9 12.13 I •6 I'3.2 O. b4 5 d.51 Z9.68 24.i=3 O,SS -3,4.9 Z9, 3 I. i= g• c�� 1 arm 1D 13? , ob 0 , SS 34.9 7.C6 I-6 ,� I Ut€r- 9 23.1 O,(z4 4.8s 10•Zg 3194 8.b�� Z3.S4- O,SS E} 23.ZA 1 _� OIL - __. - -- - ` "!mow•. _S _74- 202 h loop WRE —dl .. r p,b4W s - I+ IL NW, -WON P-* Al -ANO s 49 46-# NMW 41 t