Loading...
HomeMy WebLinkAboutDrainage Reports - 06/19/1997Repot: Da�� FINAL DRAINAGE AND EROSION CONTROL STUDY FOR HARMONY SCHOOL SHOPS FIRST FILING FORT COLLINS, COLORADO JANVARY 1997 THE SEAR -BROWN . GROUP Standards in Excellence FINAL DRAINAGE AND EROSION CONTROL STUDY FOR HARMONY SCHOOL SHOPS FIRST FILING FORT COLLINS, COLORADO May 23, 1997 Prepared for: Mark Young Construction Inc. 155 North College Avenue Fort Collins, Colorado 80524 Prepared by: The Sear -Brown Group 209 South Meldrum Fort Collins, Colorado 80521 (970)482-5922 Sear -Brown Job No. 759-001 1 THE SEAR -BROWN GROUP FULL -SERVICE DESIGN PROFESSIONALS FORMERLY RBD, INC. 209 SOUTH MELDRUM FORT COLLINS, COLORADO 80521-2603 970-482-5922 FAX:970-482-6368 May 23, 1997 Mathew Fater City of Fort Collins Stormwater Utility 235 Matthews Street Fort Collins, CO 80522 RE: FINAL DRAINAGE AND EROSION CONTROL PLAN FOR THE HARMONY SCHOOL SHOPS FIRST FILING Dear Mathew: We are pleased to submit to you the Final Drainage and Erosion Control Plan for The Harmony School Shops First Filing. We have addressed your final comments dated May 16, 1997, and all computations within this report have been completed in compliance with the City of Fort Collins Storm Drainage Design Criteria Please call should you have any questions. Sincerely; The Sear -Brown Group ' Prepared By: ' Robert Hume, P.E. Project Manager Enclosure Reviewed By: Kevin W. Gingery, P.7 . Senior Engineer NEW YORK•PENNSYLVANIA ' COLORADO•UTAH STANDARDS IN EXCELLENCE EOUAL OPPORTUNITY EMPLOYER TABLE OF CONTENTS ' DESCRIPTION PAGE ' I. GENERAL LOCATION AND DESCRIPTION .............................. 1 A. Location.......................................................1 II. B. Description of Property ........................................... DRAINAGE BASINS .................................................. 1 1 ' A- Major Basin Description ........................................... B. Sub -Basin Description ............................................ 1 2 III. DRAINAGE DESIGN CRITERIA ........................................ A- Regulations....................................................2 2 B. Development Criteria Reference and Constraints ........................ 2 C. Hydrological Criteria ............................................. 2 ' D. Hydraulic Criteria................................................2 E. Variance from Criteria ............................................ 2 IV. DRAINAGE FACILITY DESIGN ......................................... 3 A- General Concept.................................................3 ' B. Specific Details .................... :............................. 3 ' V. STORM WATER QUALITY ............................................ A General Concept.................................................4 4 ' VI. EROSION CONTROL ................................................. A General Concept.................................................4 4 ' VII. CONCLUSIONS...................................................... A Compliance with Standards ......................................... 4 4 B. Drainage Concept................................................5 ' REFERENCES............................................................5 ' APPENDIX VICINITY MAP............................................................1 ' HYDROLOGY.............................................................2 ' DETENTION.............................................................14 ' EROSION CONTROL ...................................................... 18 ' FINAL DRAINAGE AND EROSION CONTROL STUDY FOR HARMONY SCHOOL SHOPS P.U.D., FIRST FILING ' FORT COLLINS, COLORADO I. GENERAL LOCATION AND DESCRIPTION A. Location ' The Harmony School Shops P.U.D., First Filing is located on the northeast corner of the Harmony Road and Timberline Road intersection. The site location can also be described as situated in the Southwest 1/4 of Section 32, Township 7 North, Range 68 West of the 6th P.M., City of Fort Collins, Larimer County, Colorado. The site location can be seen on the vicinity map in the Appendix. B. Description of Property Harmony School Shops P.U.D., First Filing will contain approximately 3.2 acres, more or less. Presently the property is undeveloped agricultural land and the historic site of Old Harmony School which is to remain as part of the development. Topographically the site gently slopes from southwest to northeast at ' approximately 1.0 percent. The Warren Lake ditch crosses the property in a southeasterly direction from Timberline Road to Harmony Road. There are no major drainageways contained within the site. ' H. DRAINAGE BASINS ' A. Major Basin Description The proposed Harmony School Shops lies within Reach 2 of the Fox Meadows ' drainage basin and Basin 1 of the Timberline Farms Master Drainage Plan. Other than the undeveloped land parcel just east of the Harmony School Shops site, Timberline Farms drainage basin is built out primarily with a residential development known as Sunstone Village. The site is largely influenced by this development downstream and north of the subject site. Stormwater discharge in this basin is limited to the 2-year historic runoff as determined by the 1989 ' Timberline Farm P.U.D. SWMM update of Fox Meadows Master Drainage Plan. Warren Lake Ditch will be relocated in a pipe to the satisfaction of the ditch ' company. Presently the developer is in the process of designing the new alignment and obtaining the necessary approvals by the ditch company. . B.. Sub -Basin Description ' The Harmony School Shops First Filing has been broken into 5 sub -basins. Sub - basins 1-3 will be developed into a new school incorporating the existing Old Harmony School. Sub -basin 4 contains Harmony Road which fronts the site to the ' south. Sub -basin 5 contains Timberline Road which fronts the site to the west. These sub -basins are shown on the Drainage and Erosion Control Plan in the back ' of this report. M. DRAINAGE DESIGN CRITERIA A. Regulations ' The City of Fort Collins Storm Drainage Design Criteria is being used for the subject site. tB. Development Criteria Reference and Constraints The Fox Meadows Master Drainage Plan, Timberline Farm P.U.D. and Sunstone Village 7th and 8th Subdivision P.U.D. Preliminary and Final Storm Drainage Reports are the governing drainage criteria for Harmony School Shops P.U.D. site development. ' C. Hydrological Criteria The Rational Method for determining surface runoff is used for the project site. ' The 2-year, 10-year, and 100-year storm event criteria, obtained by the City of Fort Collins, is used to determine the design rainfall and resulting runoff values. Retention pond sizing by FAA Method is used to determining required the ' temporary retention pond volume. These calculations are included in the Appendix of this report. ' D. 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. E. Variance from Criteria ' No Variances are being sought for the proposed project site. I 2 ' IV. DRAINAGE FACILITY DESIGN ' A. General Concept ' Harmony School Shops First Filing is intended to develop in accordance with the general concept described in the Preliminary Drainage and Erosion Control Study for the Harmony School Shops P.U.D., by RBD Inc., October, 1995. Ultimately ' the majority of the runoff from this site will be detained in the regional detention pond located on the northeast corner of the Harmony School Shops P.U.D. site. For the purpose of obtaining approvals on the First Filing, without incumbering the ' developer with unnecessary off -site improvements, the basic drainage concept is to provide a temporary retention pond/sediment trap to contain developed flows from sub -basins 1-3. The temporary retention pond will be contained in a temporary drainage easement and is sized to store the volume of two 100-yr storm events. Final design of the regional pond will be deferred to future final filings of the Harmony School Shops, P.U.D. as the need for utilizing the space arise. B. Specific Details Sub -basin 1 is located on the south side of the Old Harmony School and the new addition to the school. This basin is mostly playground and landscaped area. It ' drains from west to east in small swale which outfalls into the southwest corner of the parking lot on the east side of the old school. This parking lot and the remaining landscaped area adjacent and to the south are contained in sub -basin 3. Flows from sub -basin 1 will be conveyed through sub -basin 3 to the temporary retention pond either as sheet flow across the pavement or gutter flow. Sub -basin ' 3 also contains a small offsite area to the east and the temporary retention pond just north of the access road. Sub -basin 2 contains the balance of the playground and the landscaped area on the ' west and north side of the site. It also captures all the roof area runoff from both structures. Flow is conveyed by a grassy swale originating at the southwest corner ' of the site then turning east at the northwest corner of the new addition. Sub -basin 4 contains Harmony Road and a small amount of landscaped area ' fronting the road. Flow quantity and pattern from this basin will remain unchanged. Storm waters are conveyed by curb and gutter to the east and outfall onto the Harmony School Shops site where the curb and gutter ends just east of ' the subject site. Runoff from this basin will be addressed and accommodated into the overall site drainage plan when the south access road for Harmony School Shops site is constructed. 1 3 Sub -basin 5 contains Timberline Road fronting the site on the west. As with sub - basin 4 the flow quantity and pattern of sub -basin 5 will remain unchanged. Storm waters are conveyed by curb and gutter to the north where it is eventually detained in a regional detention pond in Sunstone Village 8th Filing. Drainage from this basin is addressed in the Final Drainage Report for Timberline Road by Northern ' Engineering, July, 1994. Existing conditions at the access road at Timberline prohibit the capture of storm water flow from this basin as originally intended in the above cited drainage plan. This access road was constructed with the Diamond Shamrock project and was constructed with a high point at approximately 50 feet east of Timberline. To accomodate for this constraint, release rates from the Harmony School Shops detention pond may need to be re-evaluated in the final design of that pond. V. STORM WATER QUALITY A. General Concept ' Very little, if any, storm water will actually leave the site as designed. The retention pond will serve as a sediment trap to capture all sediment transported by runoff. During the final design phase of future filings the developer will seek to find an acceptable method for water quality treatment of storm water runoff in conjunction with the final design of the regional detention pond. VI. EROSION CONTROL A. General Concept ' This development lies within the Moderate Rainfall Erodibility Zone and Moderate Wind Erodibility Zone per the City of Fort Collins zone maps. A variety of various Best Management Practices have been utilized in compliance with the City of Fort Collins Design criteria to minimize erosion during construction of the Project. VIL CONCLUSIONS ' A. Compliance with Standards All computations completed in this report are in compliance with the City of Fort Collins Storm Drainage Design Criteria Manual. 1 4 17 B. Drainage Concept The proposed drainage concept adequately provides for the transmission of developed on -site runoff and provides ample temporary retention minimizing any adverse affects to downstream property or hydraulic features. REFERENCES 1. 2. 3. 4. 5. 6. 7. 8. Storm Drainage Design Criteria and Construction Standards, City of Fort Collins, Colorado, May 1984, revised March 1991. Erosion Control Reference Manual for Construction Sites, City of Fort Collins, Colorado, January 1991. Master Drainage Plan for Timberline Farm P.U.D., by Engineering Professionals, Inc., September, 1989, revised November, 1989. Sunstone Village 7th Subdivision P.U.D. Preliminary and Final Storm Drainage Report, by Land Services, Inc., June, 1993. Sunstone Village 8th Subdivision P.U.D. Preliminary and Final Storm Drainage Report, by Land Services, Inc., June, 1993, revised August, 1993. Final Storm Drainage and Erosion Control Report for Milestone Drive, by Land Services, Inc., June, 1995. Final Drainage Report for Timberline Road, by Northern Engineering, July, 1994. Final Drainage and Erosion Control Study for Timberline Farms Cornerstore P.U.D., by Galloway Romero and Associates, January, 1996, Revised May, 1996. E APPENDIX n D I SEAR -BROWN 1 1 1 1 1 q d C HORSETOOTH RD. Big Horn R& o c J �f" Q of r °- o w z z D � 0 o . PROJECT .� SITE Timberline Lm HARMONY RD. VICINITY MAP SCALE: 1 "=1000' k� HYDROLOGY (a Y� ao a 0 (II c 0 L O . N N 7. U a� N N 0 d 0 U U (D CA c O O O u U 0)U U p� LO M lL II r C Q) N y a)E m LL! a. Z L a) a) (M "t CO NLO(aCDCO� Cl _ 0 V 000000 0= (avM CC) 0 c :3 ��Lriai(or� (D o) (n IT .- (a .0 N d a- a + I'(Ot�NOr- N � U Iq LO 000 CCD CY) L C C L co (n N LO r- a) fl O M O O N O E fU 000000 Q � CDNU LO co a) cC ��a)aoNN �- ot 000000 ri Co Q y (n In (n (n In (n 0 N N N N N N 0� 000000 aZi a y LO U) LO U) In In O) a) a) a) a) a) O 0 0 0 0 0 0 � U CL E N M V L CO O N 0 Q H 0 (n 4 of :r U O 0 11 13 O Z `- W N rn (� Z co O o U LL 0 W W o a a } 0] 20 O 0 fn FW- o >_ O g N= U ti Cl) QN W tY (OO V CnI-CM UO CO Uo Cl) Z . 'E L v O I� UO (0 0) 0 .-. 0 NC7V-U0V-:UO w . V'NN V rf r1 to00f�CMv V O rn ui -1 2 W F- > JLL1 OOtO000 �Oo 0 V'Nto(Ow co�.-.- 0 00 j F- U) >>> > > Q Q Q C� C9 C7 a a a = 000000 1� 0 (o LO 1�- V' .. N V c V c V Z �n W J 1,-CM0(MODCM 2 ^ � E O 00 CO CM CM Cf5 OO P: v Z ZW 000000 co0OD000 goo to LOODC14 U LL O U0 tO tO 0 0 0 F- � C) OD to M Un PzZ Z W _ J O a) cy) v c0 N to (O 00 00 v U M o 0 0 0 0 0 <Q^ vf�000NN Q W 0 N u 06 0 0 0 0 Q Z U) m L7 W C/)� .-NCOV LO0 UO C 0 O Co N� 7 U I>I U >,C9 O C O J w od a) � a w U) m f0 a. cu II � J U n' a) c9 a) En Q a) U > OJ f0 C II Q. 0 U 3 FQ- Y � N m W K C a F s - p N A ^ N a O1 OI m 17 N Z ^ ^^ ^ ^ W Q 2 N n m n r. O O ^fV ^ C v O w Cn a �m m mm ry e J O 00 m m W % N 2 Q m yF'j a ^ UU UU Q Q 8S 88 m y < ^ d d m n n no LL O^ ^ N ^ O O N zC� Dv u LL wz N NN Ohm h n C1 t7 COI O- ^- N C G G Z^ K:) an Oa m N W �O CO G^CI G G 0 = M 0 C N N mm N m ZN N N N N N N N w v N H IR m m O U m C C 000 C G C mo emm O n n �En ^ cm - E d J N N w ^^ c O J m LL O f CJ mo• amm O n ci 3En ^ A ^ YI ^ ^^ Cl N m N 2 n N !1 Qm �N nNn < p mm 10 ao^ 5 y I LO N II U O H Z T LIA O Z O � V O L of W CW c O 0 a. 0 a rn c } m ami Z O O Q W w cti �� c 0 0' > C E J m u = U r Y � N < �- W MCV) 0Oo00 J C Q 0L6Ui(6L6L6 Zw'E.- LL V'0N(000 O N N V-: L6 V- L6 w v F- ONMV ;t O °) W J �W H w o0Ln000 OD moo J a-aa.aa_aa.aa-a = 000000 F- I- O (o (n ll- v Z �~ W J OMCOr-V ^ ti N N F- v Q Z111 000000 (00CC) 000 a. o LO LO 03 C14 W 0 U) > O LO LO LO rn 00 ]� V'fMODLO W O7 F-Z� Z W — J 00M� it0D Nu)(OODOD'q U M 000000 (DNLO�LOOO V I�CACC) NN Q W U N 0 0 0 0 0 0 QJm Q Z U) m m � � �W (n Q r N CO V LO O O N 7 �Up U _A U O N O on. d c U (o s U O) cc (D N F- a) a coU c tcu y C 0 E d m :3 m o U � E 0 Z c N Y a v N a m Q � Ix C 09 SIN W Z a w a w�n ao F mN V vq Cl m z9go U W Z 0 W m0 1- �4m m N c EL 41�^ ui m 0 � � m Y v m O v v m J~ p W O 8 m m ZQZQZ<p� 1 w a UU UU < < wW o 8a ..- 0 op SO C u4 o 8 y'.— NV N m N m m N m m O m O m m M�- oza w �2pLL ~O z n YI F LL N A m o m m N m N �4 ' -Q mmm 0M O C 4Q f r GAD O � 0 N N Wv0 qt CC O-N G ,O C 08 80rR e 8 8 ZF rim mmm m mi m w_20 N Ui Op m N N 0 pY 0 O U m Oo 000 0 0 0 L C^ E N N G 0 Lq 1m m O O w� aEm N N W wZ s �� m F E OU J y LL O O Zva J N N O N N m O O ,J_N E CN NGO �G 0 off m Z N 0 fh N N N N CIL O m 60 i O � N p lm' I m Y O p y O V oo� Z I to A FROM: Diamond Shamrock (Timberline Farms Cornerstone, PUD) Grading, Drainage and Erosion Control Plan Sheet 3 of 7 Values used for. Harmony School Design Point B in to C), L) LLJ o 0 61 C� CO 880.C488 '8:0* c; Q'0 ROn1U 6 46 c; 0" 0 0 0 0 V) LLI (.D 'n -7 r, q C-4 C4 r, 00 8 A) 1 < 0 0 0 z N 1 PI) 1 0 W 0 ca (A 0 ch 0 0 tn 0 6!—z (n aLJ o (L RBD INC. ENGINEERING CONSULTANTS CHANNEL RATING INFORMATION HARMONY PRESCHOOL - SWALE k ( ENS IN 1� STA ELEV 0.00 1.00 22.00 0.00 27.00 1.00 'N' VALUE SLOPE (ft/ft) ----------------------- 0.060 0.0100 ELEVATION AREA VELOCITY DISCHARGE FROUDE (feet) --------- (sq ft) ------- (fps) -------- (cfs) --------- NO. ------ 0.10 0.1 0.3 0.05 0.27 0.20 0.5 0.5 0.29 0.30 0.30 1.2 0.7 0.85 0.32 0.40 2.2 0.8 1.83 0.33 0.50 3.4 1.0 3.32 0.35 0..60 4.9 1.1 5.40 0.36 0.70 6.6 1.2 8.14 0.37 0.80 8.6 1.3 11.62 0.37 0.90 10.9 1.5 15.91 0.38 Q= I.ZcFs OooX 1.33= I. to Gf5 0. 34, Dhqx @ 0too x 1. 33 = 0. 3g, E 1 1 1 1 1 RBD INC. ENGINEERING CONSULTANTS CHANNEL RATING INFORMATION HARMONY PRESCHOOL - CURB CUT SIZING STA ELEV 10.00 0.50 10.00 0.00 13.00 0.00 13.00 0.50 'N' VALUE SLOPE (ft/ft) ----------------------- 0.060 0.0100 3.0'-� 0.4� ) T ELEVATION AREA VELOCITY DISCHARGE FROUDE (feet) --------- (sq ft) ------- (fps) -------- (cfs) --------- NO. ------ 0.10 0.3 0.5 0.15 0.29 0.20 0:6 0.8 0.47 0.31 0.30 0.9 1.0 0.89 0.32 0.40 1.2 1.2 1.38 0.32 0..50 1.5 1.3 1.94 0.32 Q,00= I.Zc45 (Basu:► 1) Qloo x i.33 = 1.60cfs D100 = 0.40 Dma,x @ Q Fo0 X 1.33 = 0 '4+' RBD INC. ENGINEERING CONSULTANTS WEIR SECTION FLOW DATA Harmony Preschool - curb cut sizing WEIR COEF. 2.700 STA ELEV 0.0 100.00 0.0 99.50 8.0 99.50 8.0 100.00 ELEVATION (feet) 99.50 99.60 99.70 99.80 99.90 100.00 ti a.00= r-A� v c�---I DISCHARGE (cfs) 0.00 0.68 1.93 3.55 5.46. 7.64 RBD INC. ENGINEERING CONSULTANTS CHANNEL RATING INFORMATION HARMONY PRESCHOOL - SWALE (j (BASInI Z� STA ELEV 0.00 1.00 8.00 0.00 12.00 1.00 'N' VALUE SLOPE (ft/ft) ----------------------- 0.060 0.0140 ELEVATION AREA VELOCITY DISCHARGE FROUDE (feet) --------- (sq ft) ------- (fps) -------- (cfs) --------- NO. ------ 0.10 0.1 0.4 0.02 0.31 0.20 0.2 0.6 0.15 0.35 0.30 0.5 0.8 0.44 0.37 0.40 1.0 1.0 0.96 0.39 0.50 1.5 1.2 1.73 0.41 0.60 2.2 1.3 2.82 0.42 0.70 2.9 1.4 4.25 0.43 0.80 3.8 1.6 6.07 0.44 0.90 4.9 1.7 8.31 0.45 43c-Cs QiooX)•33= (a,25as 0100 - 0.72 D@ Qioox1.33= O•SI. i 1 1 1 i 1 1 1 1 1 1 1 1 i 1 1 1 1 1 10 RBD INC. ENGINEERING CONSULTANTS CHANNEL RATING INFORMATION HARMONY PRESCHOOL - SWALE C. (BASI" 3 STA ELEV 0.00 2.00 72.00 1.00 142.00 0.00 Unix=o,43' 162.00 1.00 'N' VALUE SLOPE (ft/ft) 0.060 0.0133 ELEVATION AREA VELOCITY DISCHARGE FROUDE (feet) (sq ft) (fps) (cfs) NO. --------- ------- -------- --------- ------ 0.10 0.5 0.4 0.18 0.31 0.20 1:8 0.6 1.11 0.34 0.30 4.1 0.8 3.28 0.37 0.40 7.2 1.0 7.06 0.39 0.50 11.3 1.1 12.79 0.40 0.60 16.2 1.3 20.80 0.41 0.70 22.1 1.4 31.38 0.42 0.80 28.8 1.6 44.79 0.43 0.90 36.5 1.7 61.32 0.44 Ci IOD' ro.e) Cfs Ql00 x 1.33 = C).OGF5 b,,, 1 1 1 '1 .1 Existing Diamond Shamrock Swale Cross Section for Trapezoidal Channel Project Description Project File c:\haestad\fmw\project2.fm2 Worksheet Usting Diamond Shamrock Swale Flow Element Trapezoidal Channel Method Manning's Formula Solve For Channel Depth Section Data Mannings Coefficient 0.060 Channel Slope 0.010000 f ift Depth 0.96 ft Left Side Slope 4.000000 H : V Right Side Slope 4.000000 H : V Bottom Width 2.00 ft Discharge 9.58 cfs 11 2.00 ft 7, z <<5 �MA� = 1.33 xh►too = 1,58 t:<S I Do, I,S b MA,4 = 0.9(at 0.96 ft 1 V H 1 NTS 0520197 FlowMaster v5.13 05:02:59 PM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 Page 1 of 1 Q 1 Existing Diamond Shamrock Swale Worksheet for Trapezoidal Channel Project Description Project File c:Xhaestad\fmw\project2.fm2 Worksheet Existing Diamond Shamrock Swale Flow Element Trapezoidal Channel Method Manning's Formula Solve For Channel Depth Input Data ' Mannings Coefficient 0.060 Channel Slope 0.010000 ft/ft Left Side Slope 4.000000 H : V ' Right Side Slope 4.000000 H : V Bottom Width 2.00 ft Discharge 9.58 cfs 1 Results Depth 0.96 ft Flow Area 5.64 ft2 Wetted Perimeter 9.95 ft Top Width 9.71 ft ' Critical Depth 0.61 ft Critical Slope 0.073733 ft/ft Velocity 1.70 ft/s ' Velocity Head 0.04 ft Specific Energy 1.01 ft ' Froude Number Flow is subcritical. 0.39 t 1 0520/97 FIOWMaster v5.13 ' 04:58:42 PM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 Page 1 of 1 1 4- DETENTION 1 Ir� -------------------------- DETENTION POND SIZING BY FAA METHOD ' Developed by Civil Eng. Dept., U. of Colorado Supported by Denver Metro Cities/Counties Pool Fund Study '----------Denver-Urban Drainage -and -Flood -Control -District, Colorado---------- USER=Kevin Gingery -Ft Collins -Colorado ....................................... EXECUTED ON 03-03-1997 AT TIME 20:11:13 PROJECT TITLE: HARMONY PRESCHOOL RETENTION POND DRAINAGE BASIN DESCRIPTION BASIN ID NUMBER = 3 ' BASIN AREA (acre)= 2.13 RUNOFF COEF 0.67 ***** DESIGN RAINFALL STATISTICS 1 DESIGN RETURN PERIOD (YEARS) = 100.00 INTENSITY(IN/HR)-DURATION(MIN) TABLE IS GIVEN DURATION 5 10 20 30 40 50 60 80 100 120 150 180 INTENSITY 9.0 7.2 5.2 4.2 3.5 3.0 2.6 2.1 1.7 1.5 1.2 1.0 ***** POND OUTFLOW.CHARACTERISTICS: MAXIMUM ALLOWABLE RELEASE RATE = 0 CFS ' OUTFLOW ADJUSTMENT FACTOR = 1 AVERAGE RELEASE RATE = 0 CFS ' AVERAGE RELEASE RATE = MAXIMUM RELEASE RATE * ADJUSTMENT FACTOR. ***** COMPUTATION OF POND SIZE -------------------------------------------------- RAINFALL RAINFALL INFLOW OUTFLOW REQUIRED DURATION INTENSITY VOLUME VOLUME STORAGE ' INCH/HR ACRE -FT ACRE -FT ACRE -FT ---MINUTE ------------------------------------------------- 0.00 0.00 0.00 0.00 0.00 5.00 9.00 0.09 0.00 0.09 ' 10.00 7.20 0.14 0.00 0.14 15.00 6.19 0.18 0.00 0.18 20.00 5.18 0.21 0.00 0.21 25.00 4.68 0.23 0.00 0.23 30.00 4.17 0.25 0.00 0.25 35.00 3.84 0.27 0.00 0.27 40.00 3.50 0.28 0.00 0.28 ' 45.00 3.25 0.29 0.00 0.29 50.00 3.00 0.30 0.00 0.30 ' 55.00 2.80 0.31 0.00 0.31 ' 60.00 2.61 0.31 0.00 0.31 No 65.00 2.47 0.32 0.00 0.32 70.00 2.34 0.32 0.00 0.32 75.00 2.20 0.33 0.00 0.33 80.00 2.06 0.33 0.00 0.33 85.00 1.97 0.33 0.00 0.33 90.00 1.88 0.34 0.00 0.34 95.00 1.79 0.34 0.00 0.34 100.00 1.70 0.34 0.00 0.34 105.00 1.64 0.34 0.00 0.34 110.00 1.58 0.34 0.00 0.34 115.00 1.51 0.34 0.00 0.34 120.00 1.45 0.34 0.00 0.34 125.00 1.41 0.35 0.00 0.35 130.00 1.36 0.35 0.00 0.35 135.00 1.32 0.35 0.00 0.35 140.00 1.28 0.35 0.00 0.35 145.00 1.23 0.35 0.00 0.35 150.00 1.19 0.35 0.00 0.35 155.00 1.17 0.36 0.00 0.36 160.00 1.14 0.36 0.00 0.36 165.00 1.12 0.37 0.00 0.37 170.00 1.10 0.37 0.00 0.37 175.00 1.07 0.37 0.00 0.37 180.00 1.05 0.37 0.00 0.37 185.00 1.05 0.39 0.00 0.39 ----------------------------------------------------- THE REQUIRED POND SIZE = .3850197 ACRE -FT THE RAINFALL DURATION FOR THE ABOVE POND STORAGE= 185 MINUTES QETQJ i i on REC D = C) .385 X Z = O • ? -7 AC • FT, ' RBD, Inc., Engineering Consultants ' HARMONY PRESCHOOL 759-001 Retention Pond Area -Capacity Rating Curve V = d/3*(A+(AB)A(1/2)+B) ' Cumulative Elev Area Volume Volume ' A (ac) (ac-ft) (ac-ft) ' ------------------------------- 4957.0 4957.0 0.00 0.09 ---------------- 0.00 0.00 ---------------- 0.00 0.00 4958.0 0.13 0.11 0.11 4959.0 0.17 0.15 0.26 ' 4960.0 0.22 0.19 0.45 4961.0 0.27 0.24 0.70r_ C),-77 AC,. FT ' 4962.0 0.32 0.29 0.99 @ 'q� l 25 1 0.3 N 0.25 c0 Q . 0.2 ' U ( n 0.15 ' 0.1 4956 1 4959 4960 4961 4962 Stage (ft elevation) - Area Capacty Al 1% 06-Mar-97 EROSION CONTROL ' RBD, Inc., Engineering Consultants RAINFALL PERFORMANCE STANDARD EVALUATION ' #759-001 1 1 PROJECT: Harmony School Shops - First Filing STANDARD FRM A CALCULATED BY: wbt DATE: 01/21/97 DEVELOPED ERODIBILIT Asb Lsb Ssb Lb Sb PS SUBBASIN ZONE ac ft % ft 1 moderate 0.46 330 0.9 47.6 0.1 2 moderate 0.72 470 1.6 106.1 0.4 3 moderate 0.95 245 3.9 73.0 1.2 4 moderate 0.25 195 1.1 15.3 0.1 5 moderate 0.81 530 1.0 134.6 0.3 Total 3.19 376.5 2.0 80.9 EXAMPLE CALCULATIONS ' Lb = sum(AiLi)/sum(Ai) = (0.46 is 330 +... + 0.72 x 470)% 3.19 376.5 ft Sb = sum(AiSi)/sum(Ai) = (0.46 x 0.90 +... + 0.72 x 1.60)/ 3.19 = 2.0 % PS (during construction) = 80.9 (from Table 8A) PS (after construction) = 80.9/0.85 = 95.1 IV RBD, Inc., Engineering Consultants EFFECTIVENESS CALCULATIONS V37.L9aITiSi PROJECT: Harmony School Shops - First Filing STANDARD FORM B CALCULATED BY: wbt DATE: 01/21/97 Erosion Control C-Factor P-Factor Comment Number Method Value Value 3 Bare Soil - Rough Irregular Surface 1 0.9 4 Sediment/Basin Trap 1 0.5 5 Straw Bale Barrier 1 0.8 8 Silt Fence Barrier 1 0.5 39 Hay or Straw Dry Mulch (1-5% slope) 0.06 1 0 Existing surface not disturbed 0 1 SUB PS AREA BASIN % ac Site 80.9 3.19 SUB SUB AREA Practice C *A P * A Remarks BASIN AREA ac DURING CONSTRUCTION 1 1 0.46 5 0.46 0.37 Straw Bale Barrier 2 2 0.72 39 0.04 0.72 Hay or Straw Dry Mulch (1-5% slope) 3 3 0.95 39 0.06 0.95 Hay or Straw Dry Mulch (1-5% slope) 4 4 street area 0.22 -0 0.00 0.22 Existing asphalt surface 4 outside street 0.03 3 0.03 0.03 Bare Soil - Rough Irregular Surface 5 5 street area 0.65 0 0.00 0.65 Existing asphalt surface 5 outside street..- 0.16 3 0.16 ...0.14 _ Bare Soil - Rough Irregular Surface Total 3.19 Cnet = [0.46x1.00+...+0.95x1.00Y0.46 = 0.24 Pnet = 0.8x[0.46x0.80+...+0.95x0.80j/0.46 0.77 EFF = (1-C*P)100 = (1-0.24*0.77)100 = 81.84 > 80.9 (PS) RBD, Inc., Engineering Consultants 2 I ' EFFECTIVENESS CALCULATIONS #759-001 t 1 .. PROJECT: Harmony School Shops - First Filing STANDARD FORM B CALCULATED BY: wbt DATE: 01/21/97 Erosion Control C-Factor P-Factor Comment Number Method Value Value 9 AsphalUConcrete Pavement 0.01 1 16 Established Grass Ground Cover - 70% 0.04 1 18 Established Grass Ground Cover - 90% 0.025 1 0 Existing surface not disturbed 0 1 SUB PS AREA BASIN % ac Site 95.1 3.19 SUB SUB AREA Practice C *A P * A Remarks BASIN AREA ac AFTER CONSTRUCTION 1 1 0.46 18 0.01 0.46 Established Grass Ground Cover - 90% 2 2 0.72 16 0.03 0.72 Established Grass Ground Cover - 70% 3 3 parking 0.50 9 0.01 0.50 AsphalUConcrete Pavement 3 landscaped 0.45 18 0.01 0.45 Established Grass Ground Cover - 90% 4 4 street & sidewalk area 0.22 9 . 0.00 . 0.22 AsphalUConcrete Pavement 4 outside street 0.03 16 0.00 0.03 Established Grass Ground Cover - 70% 5 5 street area 0.65 9 0.01 0.65 AsphalUConcrete Pavement 5 outside street 0.16 16 0.01 0.16 Established Grass Ground Cover - 70% Total 3.19 Cnet = [0A6x0.03+...+0.45x0.03y0A6 = 0.02 Pnet = 0.8x[0.46x1.00+...+0.45x1.00]J0.46 = 1.00 EFF = (1-C*P)100 = (1-0.02*1.00)100 = 97.72 > 95.1 (PS) ZZ RBD, Inc., Engineering Consultants EROSION CONTROL COST ESTIMATE O CHarmony School Shops - First Filing 9-0 PREPARED BY: wbt DATE: 01/21/97 CITY RESEEDING COST I Unit I ota Method Quantity Unit Cost Cost Notes Reseed/mulch 3.19 ac $650 $2,074 See Note 1. Subtotal $2,074 Contingency 50% $1,037 Total $3,110 EROSION CONTROL MEASURES Unit Total Number Method Quantity Unit Cost Cost Notes 5 Straw Bale Barrier 3 ea . $150 $450 8 Silt Fence Barrier 450 LF $3 $1,350 39 Hay or Straw Dry Mulch (1-5% slope) 3.19 ac $500 $1,595 59 Seeding (Native) 3.19 ac $305 $973 Subtotal $4,368 Contingency 50% $2,184 Total $6 551 Total Security $6 551 Notes: 1. A<=5 ac=$650/ac; A>5 ac=$531/ac. 23 THE SEAR -BROWN GROUP FULL -SERVICE DESIGN PROFESSIONALS ' FORMERLY RBD, INC. 209 SOUTH MELDRUM January 21, 1997 FORT COLLINS, COLORADO 80521-2603 ' 970-482-5922 FAX:970-482-6368 Mr. Basil Hamdam City of Fort Collins - Stormwater Utility 235 Mathews Fort Collins, CO 80522 ' RE: Harmony School Shops, First Filing Dear Basil: This letter is to outline our erosion control measures cost estimate for the security deposit related to this project. The City of Fort Collins Current Cost Factors will be used for this estimate. There will be approximately 3.19 acres disturbed within this project. Using the city revegetation ' criteria of $650.00 per acre for sites less than 10 acres in size, and 150% contingency, the total obligation of the contractor for a security deposit would be: ' (3.19 acres) x ($650.00/acre) x (1.5) = $3,110.00 ' A cost breakdown of the erosion control measures that will need to be installed is as follows: Straw Bale Check Dams (3 @ $150.00 ea.) = $ 450 450 L.F. of Silt Fence (@ $3.00/L.F.) = $1350 Straw Dry Mulch (@ $500/ac) = $1595 Seeding (Native @ $305/ac) = $ 973 TOTAL x 150% CONTINGENCY = $6551 Therefore, the larger amount, or the amount of security deposit obligation should be in the amount ' of $6,551.00 ' Please call with any questions regarding this estimate. Sincerely, ' Sear-Bromm Group ' Bill Taylor 1 NEW YORK •PENNSYLVANIA COLORADO•UTAH STANDARDS IN EXCELLENCE EQUAL OPPORTUNITY DMPLOl ER EROSION CONTROL NOTES t0.3 I we 1.2 cfe 9'] Q1C0 we 4J city Old' 164ch �� GeeXse 6.251 THE CITY OF FORT LEAST 24S STORM WATER UPUTY EROSION CONTROL INSPECTOR SI . MUST BE NOTIFIED AT LEAST 24 HOURS PRIOR i0 ANY CONSTRUCTION ON THIS SITE. S we1.0(1; NIN. S - 1.Mf MIN. ALL REQUIRED PERIMETER SILT FENCING SHALL BE INSTALLED PRIOR TO ANY LAND 1 L J1 bell0.38 1 J1 dNgg,e- 0,81' DISTURBING ACTIVITY (STOCKPIUNG, STRIPPING. GRADING. EX.) ALL OTHER REWIRED p2 5 8 4 EROSION CONTRW MEASURES SHALL BE INSTALLED AT THE APPROPRIATE TIME IN THE CONSTRUCTION SEQUENCE AS INDICATED IN THE APPROVED PROJECT SCHEDULE, Ola9 we 6.8 cfe CONSTRUCTION PLANS, AND EROSION CONTROL REPORT, SECTION A SECTION B d1oD- 0.39' PRE -DISTURBANCE VEGETATION SHALL BE PROTECTED AND RETAINED WHEREVER cose.3 OMAewe 9.0 cfe POSSIBLE. REMOVAL OR DISTURBANCE OF EXISTING VEGETATION SHALL BE UNITED S we 1.335 MIN. TO THE AREA REWIRED FOR IMMEDIATE CONSTRUCTION OPERATIONS. AND FOR THE SHORTEST PRACTICAL PERIOD OF TIME. g68 I� �I Olm we 7.2 FDA deu• 0.43' ALL SOILS EXPOSED DURING "NO DISTURBING ACTIVITY (STRIPPING, GRADING, UTUTY dlgg= QuXws 0.85' 9.58 cfa INSTALUTIONS, STOCKPILING, III ETC.) SHALL BE KEPT IN A ROUGHENED ' CONDITION BY RIPPING OR DISCING ALONG LAND CONTOURS UNTIL MULCH, VEGETATION, S we 1.00% MIN. SECTION ON OTHER PERMANENT EROSION CONTROL IS INSTALLED. NO SOILS IN AREAS OUTSIDE C PROJECT STREET RIGHTS-CF-WAY SHALL REMAIN EXPOSED BY LAND DISTURBING Jt dBeew 0.96' 3 ACTIVITY FOR MORE THAN THIRTY (30) DAYS BEFORE REWIRED TEMPORARY OR 4 PERMANENT EROSION CONTROL (E G SEED/IAULCH LANDSCAPING ETC) IS INSTALLED UNLESS OTHERWISE APPROVED BY THE STORAWATER U'RUTY. ^ else THE PROPERTY SHALL BE WATERED AND MAINTAINED AT ALL TIMES DURING SECTION O 19v CONSTRUCTION VTES SHALL LL AS IMMEDIATELY PREVENT WIND -CAUSED EROSION. ALL LAND J //.' / 4v0' aysb DISTURBING ADJACENT NPES SHALL S. IMMEDIATELY DISCONTINUED THE CI MEN FORT CCE DUST IMPACTS ADJACENT PROPERTIES, AS DETERMINED BY THE CITY W FORT GOWNS, ENGINEERING DEPARTMENT. AND REPAIRED OR TED AS Y AFTER EACbI UNOFF EVENT ORDER TO ASSURE CONTVN DC PERFORMANCE OF R THEIR INTENDED RFUNCCIION. ALL r W sae uWee oiya ba lone are ode .nr, roumavmn central measures « ALL TEMPORARY STRUCTURAL EROSION CONTROL MEASURES SHALL BE INSPECTED EROSON CONTROL CONSTRUCTOR SEQUENCE Ind RETAINED SEDIMENTS, PARTICULARLY THOSE ON PAVED ROADWAY SURFACES, SHALL y y,,, In be memuea. BE REMOVED AND DISPOSED OF IN A MANNER AND LOCATION $O AS NOT TO CAUSE Moor mmMatlons w an approna scheaole may reaulre whrfril a nn eN s far THEIR RELEASE INTO ANY ORAINAGEWAY. appi by the City Engineer TEMPORARY CONSTRUCTION SOIL STOCKPILES SHALL NOT EXCEED EIGHT (8) FEET IN HEIGHT, AND SHALL BE PROTECTED FROM SEDIMENT TRANSPORT BY SURFACE ROUGHENING. WAFERING, AND PERIMETER SILT FENCING. CITY ORDINANCE PRON18115 THE TRACKING, DROPPING, OR DEPOSITING OF SOILS OR ANY OTHER MATERIAL ONTO CITY STREETS BY OR FROM ANY VEHICLE. ANY INADVERTENT DEPOSITED MATERIAL SHALL BE CLEANED IMMMEOIATELY BY THE T: CONTRACTOR. ( p I �I EXISTING DIAMOND SHAMROCK L ,1 1 I , I , Lo---- 13 a a i0.99AC / I we ! IF Mwe we hv 1WJ 2 we 1F I 5 I D.25AC v I I 195, EXISTING S1TE HYDROLOGY TOTAL ON -SIZE AREA: 2.13 AC. RATIONAL 'C': QM DEVELOPED SITE HYDROLOGY DESIGN PONT BASN AREA (a0.) C old (cfe) Olgp (of$) 10 1 0.46 0.29 0.3 1.2 20 2 0.72 0.59 1.2 4.7 30 3 0.95 0.63 1.9 6.8 30 1,3 1.41 0.52 1J I 40 4 0.81 0.81 1.7 6.8 50 5 0.25 0.84 0.7 2.3 B M-4, OS-5, 0-1. B 2.18 0.48N 2.64• 9.2 V r m� g 1' r •. NC VALUE FOR BASIN 0-1 . weQ FOR BASN B IS CALCULATED 0 FOR BASIN 0-1, PLUS OFFSIM 0 FROM DIAMOND SHAMROCK (SEE DRAINAGE REPORT) ` n97a a956 n9 ifi a95B <99 SEEDING CHART Table 11 z. Re.ammenaw S9A M and Well Rates of Seethe m far T.npomry coastal and/or Crier, Daps. bxW 5,l DPBIM pa... Armed Rpg.ao Coast 20 Oats Cod To Gw Rr d 80 "tot - Wnb, COOO 40 All - Spying so SCALE 1'=50' Bdtp woa 60 „1 t d 30 world Sadd.. Worm 15 harshly won 10 hyl M major growth eHM 'e will oeir f summon Table 1111 the 4 yeni plorFg Worm U0100 eM we far primal n emmboyA,re, brale grass". Tonle ILL Plowing opt" fan PrrnW and Tempo-On/caw, LEGEND Crn crane. I Pp W& TEMPMAm/COAR GRASSES CROP MAKES wmm �ad sell .06 EXISTING CONTOUR non a - Feb 28 e� 64� PROPOSED CONTOUR use 01 - y 15 Yes Yes ye Na May s 16 - May 31 Yes No m - As 31 No No Y" No DIRECTION OF FLOW Aug 01 - Aug 31 Na Yes No Yea SeP o1 - Sep w Yes DESIGN PONT Pat 01-Om 31 No No e Na ay5, DRAINAGE BASIN BOUNDARY BASIN NUMBER MULCHING CHART e 3 ABTA BASIN AREA krulneg wal be u,ad la et in MopRdmt mR wityp 'm. One by Of of the . npbem"'i eass nnd d A peeV d TOSS wal emat", Ora tempo. y �egelalm I raP Oydi AVERAGE STREET SLOPE c.ptaeY Apni Rate -...$ Still w/ ROW ARROW Mulch Olt" m 01 -"Dec v ane/m, =... l� SCALE w/ UNOERDRAIN s m woo xgma c yt npr> 01 - may31 N tam/ens Emelaall t ba f°^ai. by bn.u.Ll Aa: m - DecO.a v m Ovpame M � STRAW BALE CHECK DAM be o .ono ch free chum sh ung AN natwy Oei hav l the 0 , m,wl wan . OnowAume mu multi, m tend lone. am a.�t ---- EXISTING STORM DRAIN PIPE It eri l 'e awes hpa. r re we may be hipped Oam March 15 these Sol 30 N Mulch aY Or straw-N M N- SILT FENCE 1. N y Orto. muu,a be ...hamd m NO yet by nne If me iaywng me F') A cryeacer wifely will crimp the fully four inmer Or anal be 10 ii by Your 11 119th (e) n nsba e v 1 "mono a t'me 1`I acFenf naabot be, the mulch to the CALL UTILITY NOTIFICATION merwNi 2 u eon, or a e 1fill new, 495a CENTER OF COLCHRADO 1=800NA922=1987 r- 4 OR 534-6700 M CALL 2 �" DAYS IS "INSIDE ... _ _ _ 4959 6L4F�W m ORE. CN RGVAR •L -_ 960 - NUMBER U m HARMONY ROAD - - - - _ _ _ _ City of Fort Collins, Colorado 1 SILT FENCE e Cfie CUULVWEFFT ' �_ _ _ _ - _ �- �\ orb, - - - - - - UTILITY PLAN RAPPROVAL 96F J �eeMBU e�-7F - _ -- 9965 19fi0 0] -�IB R_P 1. 4963 0 APPRDSED: Unebr 0I Deu F �e FBIim r9 Irraw Inmem l.il�n�-asi e - - _ �` LaMafierlae - - _- - - wog - - - CHECKED BY: Teta R TeMeier ULJity Oetfi - J a9fip -- - - _ - ECKED BY LOgmAler T Oe4 - _ CH UBDI -_- _- - CHE CKED BY.-- - - - - - - - - - - - - - - - fi_ \1B RCPL 955 5 95 0960 PerIG B R6CRG4_� 9p_ De11 by A CHECKED BY: IM� \ CNECKED BY: EXISTNGS_ CURB CUT Is 38'N 60w HDROP CEO .8T STRAW BALE 1 PIPE ATON wbz - s65' 63- YEAR IM9T MONTH J F M A M J J I A S 0 B D OVERLOT GRADING - PHASE 1 _Sell "NO EROSION I%NITBCIL W, Rwghe+mg perinetw Banner Additional BanIMN Metnaee Vepebnd �tlm _ t otw RABFNL EROSIOR'Cd TRID. STRUCTURAL / Sediment TP©/BmM Inlet Filters Steal Bon o Sit Fenn Bmlwe Sand Bags Bare Sol Presently Cartel Ful TerracMy Mphalt/Concrete P9Hng I other-aaM Mulch LLL 49$I VEGETATAE'. Permanent Sell Plontng MUIchMg/Semort Temporary Send planting Sad Inetallaxm .NettW/ ts/0kets Other STRVONRES INSTALLED BY MANTAINB3 BY VExrAnoxANLLT1Nc caTRACTw DATE SVBNITRD APPROVED BY Cltt OF iCgi CgLNS W TEMPORARY - RE TON POND/SEDIMENT TRAP el HW4961.25 AREA = ] ACRES RETENTION D we p.]l AC FT RETENTION PR0)9DED r 0.]] AC FT RELEASE RAZE - O cfe 101 55' SOD AREAS y -�-FOR EROSION CONTROL g60 we \<. ePROPERTY LINE _ - 0.I2AC FF = 66.60 . FIT we 62.76 LOT 1 3' MR 3 v v•..: ♦ CUT REMOVE 9c DISPOSE FIT = 67.93 19 OF EXISTING SHED EXISTI60w NG -6 - W o HERCP IRRIGATION PIPE we 0.46 ____6 w IIf '963 lym - - ---- -- PROPOSED Si 9 (BY OTHERS) sd / II / 1 i iSILT FENCE SS; 0 � FUTURE DEVELOPMENT � i 10x 55 '' SO 510�EA �8' CURB CUT ERO°ACRONTRW - BOTTOM ELEV. we 56.0 Ie1 4959 IM®I m as ga� � cw7 �a 0 759-001 GUMNC N0. 3 of 9