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HomeMy WebLinkAboutDrainage Reports - 06/23/1993rinal ApP.rnkled ReporPROPERTY OF t e�6c CIOLUZIWIN- FINAL DRAINAGE AND ROSION CONTROL STUDY FOR �EN HOMES OFFICE BUILDING DRT COLLINS, COLORADO FINAL DRAINAGE AND EROSION CONTROL STUDY FOR JENSEN HOMES OFFICE BUILDING FORT COLLINS, COLORADO May 18, 1993 Prepared for: Jensen Homes P.O. Box.1007 Fort Collins. Colorado 80522 Prepared by: RBD, Inc. Engineering Consultants 209 South Meldrum Fort Collins, Colorado 80521 (303) 482-6368 RBD Job No. 014-043 Engineering Consultants 209 S. Meldrum Fort Collins, Colorado 80521 303/482-5922 FAX: 303/482-6368 May 18, 1993 Mr. Glen Schlueter City of Fort Collins Utility Services Stormwater 235 Mathews Fort Collins, Colorado 80522 RE: FINAL DRAINAGE AND EROSION CONTROL STUDY FOR THE JENSEN HOMES OFFICE BUILDING, 4828 SOUTH COLLEGE AVENUE 014-043 Dear Glen: We are pleased to resubmit to you, for your review and approval, this Final Drainage and Erosion Control Study for the Jensen Homes Office Building. All computations within this report have been completed in compliance with the City of Fort Collins Storm Drainage Design Criteria. We appreciate your time and consideration in reviewing this submittal. Please call if you have any questions. Respectfully, RBD Inc. Engineering Consultants Tracy Kittell Design Engineer e= W. ttgeaOZE. Project Engineer Other Offices: Denver 303/458-5526 • Vail 303/476-6340 TABLE OF CONTENTS DESCRIPTION PAGE GENERAL LOCATION AND DESCRIPTION ............................ 1 Location................ ............................... 1 Description of Property ...................................... 1 DRAINAGE BASINS ............................................. 1 ' Major Basin Description . • . • .... • ......... • ..... • • .. • • 1 .. • ... Sub -Basin Description 1 DRAINAGE DESIGN CRITERIA ..................................... 2 ■ Regulations ............................................... 2 Development Criteria Reference and Constraints ................... 2 ' Hydrological Criteria ........................................ 2 Hydraulic Criteria .......................................... 2 Variances from Criteria ...................................... 2 ' DRAINAGE FACILITY DESIGN ..................................... 2 General Concept 2 ' Specific Details ........................................... 3 EROSION CONTROL ............................................ 4 General Concept...... ................................ 4 Specific Details ... ......................................... 4 ' CONCLUSIONS .............................. .......:....... 5. Compliance with Standards ........................... ..... . 5 Drainage Concept .................................. 5 ' Erosion Control Concept ..... 5 REFERENCES................................................ 5 APPENDIX A VICINITY MAP. .............................................. 1 HYDROLOGY & DETENTION ...................................... 2 ' EROSION CONTROL ........................................... 13 FIGURES AND TABLES 17 1. 2. REVISIONS Description First Submittal Minor Text Revisions Date 30 Mar. 93 18 May 93 FINAL DRAINAGE AND EROSION CONTROL STUDY FOR JENSEN HOMES OFFICE BUILDING FORT COLLINS, COLORADO GENERAL LOCATION AND DESCRIPTION A. Location The proposed Jensen Homes office building is to be located approximately 0.25 miles south of Harmony Road and immediately east of South College Avenue, across from the Walmart Shopping Center. More specifically, this site is located in the NW quarter of Section 1, Township 6 North, Range 69 West of the 6th Principal Meridian in Fort Collins, Colorado. The project site will occupy lots 1,2, and 3 of Fairway Estates Commercial Subdivision. B. Description of Property The proposed location for the Jensen Homes office building is located at 4828 South College Avenue in Fort Collins, Colorado. The site is presently undeveloped. The site is bounded by The Congregation Of The Living God's church (4820 South College Avenue) to the north, South College Avenue Frontage Road to the west, Albrecht's office building (4836 South College Avenue to the south, and Lot 3 of Fairway Estates First Filing to the east. DRAINAGE BASINS A. Major Basin Description The study site is located within the Fossil Creek Drainage Basin. No major drainageway exists within the proposed development site. B. Sub -Basin Description The historic drainage pattern on the study site is predominately overland flow in a southerly direction. However, a portion of the on -site runoff sheet flows west onto the Frontage Road. A small (approximately 18 inch deep) irrigation ditch located on the eastern property line of the study site also receives a portion of the historic runoff as overland flow. No off -site drainage crosses the project site. 1 III. DRAINAGE DESIGN CRITERIA ' A. Regulations The City of Fort Collins Storm Drainage Design Criteria [1] is being used for ' this study. B. Development Criteria Reference and Constraints Per the City of Fort Collins Storm Water Utility, the runoff from the developed site is not to exceed the project site's 2-year peak historic flow ' at Fairway Lane (design point 4 on Drainage and Erosion Control Plan in the Appendix). This will require the use of on -site detention. ' C. Hydrological Criteria t The Rational Method is being used to determine peak runoff flows from the study site. Rainfall criteria for this study was obtained from the City of Fort Collins [1] and is included in the Appendix. The 2-year rainfall criteria was utilized to determine historic flows. The future developed flows utilize the 10- and 100-year rainfall criteria. D. Hydraulic Criteria All calculations within this study have been prepared in accordance with the ' City of Fort Collins Drainage Criteria [1]. E. Variances from Criteria ' No variances are being requested for the project. IV. DRAINAGE FACILITY DESIGN A. General Concept The project site is proposed to be developed with an office building, ' parking, and landscaping. The proposed drainage pattern was kept as close as possible to the historic pattern. On -site detention was utilized to restrict runoff to the project site's peak 2-year historic flow at Fairway Lane. ' 2 B. Sub -basin 4 is proposed. to flow undetained from the project site. The peak 100-year flow from this sub -basin is subtracted from the project site's 2-year peak historical flow at Fairway Lane. The remaining flow was used as the basis for the total maximum release rate from on -site detention facilities. Specific Details The project site is divided into four drainage sub -basins. The sub -basins are indicated on the Drainage and Erosion Control Plan in the Appendix. A detention pond will be utilized to detain on -site runoff from Sub -basin 1. the maximum allowable release rate from Sub:basin Mwwill-be-limited to 0.09 cubic feet per second (cfs). The discharge from the detention pond will enter the south adjacent property's east parking lot from the southeast corner of the project site's east parking lot (refer to Drainage and Erosion Control Plan in Appendix). The runoff will then follow the historical drainage pattern. The runoff from Sub -basin 2 is proposed to flow into a detention pond located in the southwest corner of the project site. The maximum release rate allowed from this pond will be 0.04 cfs and will discharge into South College Frontage Road. After discharging from the detention pond, the flow will continue down the Frontage Road to Fairway Lane. n J. Sub -basin 3 is proposed to drain between Jensen Homes' office building and retaining wall (see Drainage and Erosion Control Plans). The runoff is then proposed to be removed from the site by utilizing an underdrain to facilitate percolation into the surrounding soil. This drain will be designed by others. Sub -basin 4 is proposed to drain undetained into the existing irrigation ditch, to the immediate east of the project site, and the south adjoining property. The irrigation ditch flows in a southerly direction and discharges into a pond located approximately 850 feet to the south. Flow entering the adjacent property will assume the historical drainage pattern. 3 V. EROSION CONTROL A. General Concept The proposed office building for Jensen Homes lies within the Moderate ' Rainfall and Wind Erodibility Zone [2]. The potential exists for erosion problems during construction of the driveway, parking lots, and landscaped area until the disturbed ground is paved or revegetated. Overlot grading is ' anticipated to start in the spring of 1993. Curb, gutter, and asphalt paving should be installed within six weeks of overlot grading. Permanent landscaping (grass sod) will be installed in the landscaped area as soon as ' possible after the pavement surfaces are placed. ' The Erosion Control Performance Standard (PS) for the study site was computed to be 82.14% (see Erosion Control in Appendix) per the criteria set forth in the City of Fort Collins Erosion Control Reference Manual for ' Construction Sites [2]. The effectiveness (EFF) of the proposed erosion control plan was calculated to be 99.0% (see Erosion Control in Appendix). Therefore, the erosion control plan, as detailed in this report and shown on ' the Drainage and Erosion Control Plan, meets the City of Fort Collins requirements for erosion control. B. Specific Detail After the overlot grading and utility installation has been completed, the parking lots and driveway surfaces will receive the curb, gutter, and pavement surfaces. After the installation of the curb, gutter, and pavement surfaces, the permanent landscaping surfaces (grass sod) will be installed ' to protect the bare ground. If the curb, gutter, and asphalt surfacing are not installed within six weeks ' after grading commences, then these improvements should not be included in the erosion control effectiveness calculations. In this situation, an aggregate base course shall be installed as gravel mulch in areas that will ' receive pavement surfacing. The gravel mulch shall be applied at a minimum rate of 135 tons per acre. Erosion control barriers (straw bales or silt fence) shall be installed at all detention pond structures if the above ' curb, gutter, and asphalt surfacing schedule will not be met. 1 4 VI. CONCLUSIONS A. Compliance with Standards All computations within this report have been completed in compliance with the City of Fort Collins Storm Drainage Design Criteria. B. Drainaae Concept ■ The proposed drainage concepts presented in this report and shown on the Drainage and Erosion control Plan are in compliance with the City of Fort ' Collins drainage criteria. All on -site runoff is limited to the project site's 2- year peak historic flow at Fairway Lane. Once the on -site runoff leaves the project site, it will assume the historical drainage pattern and will not ' adversely impact other property. C. Erosion Control Concept ' The proposed erosion control plan adequately provides for the control of wind and rainfall erosion from the study site. Through the construction ' sequence and proposed erosion control measures, the City of Fort Collins performance standards will be met. The proposed erosion control concepts presented in this report and shown on the Drainage and Erosion Control ' Plan are in compliance with the City of Fort Collins erosion control criteria. ' REFERENCES ' 1. City of Fort Collins, Storm Drainage Design Criteria and Construction Standards, May 1984, Revised 1992. ' 2. City of Fort Collins, Erosion Control Reference Manual for Construction Sites, January 1992. ' 3. ARIX Corporation, Drainage Report State Farm Service Center Addition, 4900 South College Avenue, Fort Collins. Colorado, August 1990 ■ ■ 5 . 1 Fol VA P. 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DEPARTMENT OF CIVIL ENGINEERING UNIVERSITY OF COLORADO AT DENVER EXECUTED ON 03-24-1993 AT TIME 14:08:27 CLIENT: DAN JENSEN PROJECT -TITLE: JENSEN HOMES PROPOSED OFFICE BUILDING - POND 1 PROJECT NO.: .014-043 FILE: tck062\jensen\pondl.out **** DRAINAGE BASIN DESCRIPTION BASIN ID NUMBER = 1.00 BASIN AREA (acre)= 0.26 RUNOFF COEF = 0. 96 (41.77 } Az s) ***** DESIGN RAINFALL STATISTICS 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 7.3 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 _ .09 CFS OUTFLOW ADJUSTMENT FACTOR = 1 AVERAGE RELEASE RATE _ .09 CFS AVERAGE RELEASE RATE = MAXIMUM RELEASE RATE * ADJUSTMENT FACTOR. ------------------- RAINFALL RAINFALL DURATION INTENSITY MINUTE INCH/HR 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 45.00 50.00 55.00 60.00 65.00 70.00 75.00 80.00 85.00 90.00 95.00 100.00 105.00 0.00 9.00 7.30 6.25 5.20 4.70 4.20 3.85 3.50 3.25 3.00 2.80 2.60 2.47 2.35 2.22 2.10 1.97 1.85 1.72 1.60 1.47 -------------------------- INFLOW OUTFLOW REQUIRED VOLUME VOLUME STORAGE ACRE -FT ACRE -FT ACRE -FT_ ------------------------------- 0.00 0.00 0.00 0.02 0.00 0.01 0.03 0.00 0.02 0.03 0.00 0.03 0.04 0.00 0.03 0.04 0.00 0.04 0.04 0.00 0.04 0.05 0.00 0.04 0.05 0.00 0.04 0.05 0.01 0.05 0.05 0.01 0.05 0.05 0.01 0.05 0.05 0.01 0.05 0.06 0.01 0.05 0.06 0.01 0.05 0.06 0.01 0.05 0.06 0.01 0.05 0.06 0.01 0.05 0.06 0.01 0.05 0.06 0.01 0.05 0.06 0.01 0.04 0.05 0.01 0.04 ----------------------------------------------------- THE REQUIRED POND SIZE = 4.855248E-02 ACRE -FT THE RAINFALL DURATION FOR THE ABOVE POND STORAGE= 75 ***** GEOMETRIES OF AN EQUIVALENT CIRCULAR POND --------------------------------------------------- STAGE CONTOUR CONTOUR POND POND (DEPTH) DIAMETER AREA SIDE SLP STORAGE FEET FEET ACRE FT/FT ACRE -FT --------------------------------------------------- 0.00 166.53 0.50 3.00 0.00 0.50 169.53 0.52 3.00 0.25 1.00 172.53 0.54 3.00 0.52 1.50 175.53 0.56 3.00 0.79 2.00 178.53 0.57 3.00 1.07 2.50 181.53 0.59 3.00 1.37 --------------------------------------------------- Fo iR A 7S /7/,vuTE RAlivfAlt DukA71GN THE PovO vetu/YE wµt aB 2IIS fT-* .2 /IS - -? - I NR _ 6. 5.3 NRS To ORAi N 7H£ PCN4 0.01 FT'1S 34-OOS 0-09fs5198Ac•r7-0 93564c>3 / AC -!7 MINUTES CLIENT: DAN JENSEN PROJECT TITLE: JENSEN HOMES PROPOSED OFFICE BUILDING JOB NO.: 014-043 FILE: tck062\jensen\pond2.out **** DRAINAGE BASIN DESCRIPTION BASIN ID NUMBER = 2.00 BASIN AREA (acre)= 0.13 RUNOFF COEF = 0. 73 (O's e i 1-2 s) ***** DESIGN RAINFALL STATISTICS 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 7.3 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 _ .04 CFS OUTFLOW ADJUSTMENT FACTOR = 1 AVERAGE RELEASE RATE _ .04 CFS AVERAGE RELEASE RATE = MAXIMUM RELEASE RATE * ADJUSTMENT FACTOR. COMPUTATION OF POND SIZE RAINFALL .RAINFALL INFLOW OUTFLOW REQUIRED DURATION INTENSITY VOLUME VOLUME STORAGE MINUTE - INCH/HR ACRE -FT ACRE -FT ACRE -FT -----------_------------------------------------------ 0.00 0.00 0.00 0.00 0.00 5.00 9.00 0.01 0.00 0.01 10.00 7.30 0.01 0.00 0.01 15.00 6.25 0.01 0.00 0.01 20.00 5.20 0.01 0.00 0.01 25.00 4.70 0.02 0.00 0.01 30.00 4.20 0.02 0.00 0.01 35.00 3.85 0.02 0.00 0.02 .40.00 3.50 0.02 0.00 0.02 45.00 3.25 0.02 0.00 0.02 50.00 3.00 0.02 0.00 0.02 55.00 2.80 0.02 0.00 0.02 60.00 2.60 0.02 0.00 0.02 65.00 2.47 0.02 0.00 0.02 70.00 2.35 0.02 0.00 0.02 75.00 2.22 0.02 0.00 0.02 80.00 2.10 0.02 0.00 0.02 85.00 1.97 0.02 0.00 0.02 90.00 1.85 0.02 0.00 0.02 95.00 1.72 0.02 0.01 0.02 100.00 1.60 0.02 0.01 0.02 105.00 1.47 0.02 0.01 0.01 ----------------------------------------------------- THE REQUIRED POND SIZE = 1.786282E-02 ACRE -FT =77afFT' THE RAINFALL DURATION FOR THE ABOVE POND STORAGE= 75 MINUTES ***** GEOMETRIES OF AN EQUIVALENT CIRCULAR POND ----------------------------------------------------- STAGE CONTOUR CONTOUR POND POND (DEPTH) DIAMETER AREA SIDE SLP STORAGE FEET FEET ACRE FT/FT ACRE -FT ----------------------------------------------------- 0.00 166.53 0.50 3.00 0.00 0.50 169.53 0.52 3.00 0.25 1.00 172.53 0.54 3.00 0.52 1.50 175.53 0.56 3.00 0.79 2.00 178.53 0.57 3.00 1.07 2.50 181.53 0.59 3.00 1.37 ----------------------------------------------------- FcA A 7S 171,varf Ri41NF19[4( Di4,e4714,N TNf 00/VO vOcui7F _ w/cL Of 77r Fri 77PF73 y /NR 5.10 NRJ To ORA/N TNf Pouf o,C4 FT'/J.. 3600 r 0 IV2Z NC Engineering Consultants CLIENT JENJEN NO h ITS - JOB NO. 0/f-09-? PROJECT S. Ccat E,- E OFF/cE 6�4a CALCULATIONSFOR pE TE,v 7ioN Powp-r MADE BVLAC DATEz9174le VCHECKED BY- DATE SHEET Z OF Z L �[/ETERH/.VE DETENT%ON' Ppti/OJ Du'lLEY-ORF%cF S/�,�5 TI -7.-! NO R.Y_j�LtG _ (EAJTJ PARK/N(r: c0)" _ "✓�9 E<�EL.�/JE d1 •�iO9C 1 T- L i ,cAaTel hIL 40 S 3 z2=Fr �S of <s f fofJ .Zr (w£JT LA,vDJCA PPEO 9:.RE�) I 1) Po /✓D ?_ _ gJ_%RX ALtOwABt1E REtE4r� RRTE -O G4� I !_ djAvAl[AOLEN�AO SOQ977=CS40�S+�/zd) V _ S0L1l7"lLN l iNBML3000 ^F NYOiBuL/CIS LR/�TER 4/ti'� - - i - '_ — FT - - i _ 1 _.� - t L t l - J uSEi"/ Sp _0l TtfTER ' - - O / } GA7- - :.Z_ TRr.., /} D/q _ �L_= ` A p /G / i 2 32 F- t US•E`I �/ j4. GRfvc£ -� _ ff 0/AiYETEk�� '. NO,TE.. Q.ECyuJt oAS!7ALL�. O/PF/CE JTRAtsN+'S�REfNG✓/tL J f _S/DES_._ + NEED Ta RE //✓J T A[;L E10 AROu �/O OPE. n//A/b TD RE_Du[E / L L /M/NOTE :i - - EROSION CONTROL _ RAINFALL PERFORMANCE'STANDARD.EVALUATION STANDARD FORM A PROJECT:✓E,vsE v hNcnes OFfica `B&'1iD1A1e- COMPLETED. BY:. T A,17rEci __ DATE: 24 1,719N 4B DEVELOPED ERODIBILITY Asb Lsb Ssb Lb Sb PS SUBBAySIN_ ZONE (ac). (ft) ($) (feet) 1 3 0, l3 /00 6. lS Qe g z 0,0.5 /00- o.sz e 17S 5,.2 9 81, 14 FRoM 7Aoce 8R 6 c t. J4 As Asb 16z (2G Fr r0.26GC�+ (/GOFTr ,13tr[)t( GFr y0. �oLJfi/ bFrMO n[� O. S1 ac L6= /7 fr Sb= �e Ss Asb i sb Sb = 2.5 q +O.11ioc C6 /5-yO,l�ac • /rt0,f0,�$ D,OSacJ O,S1 G c MARCH 1991 8.14 DESIGN CRITERIA PROJECT: T-,sMsS v NonFS OFF/CE 4344a • STANDARD FORM B .,K/T7ELL` = DATE: 24/Y/4f 93 COMPLETED BY:-.-,7 Erosion Control - C=Factor` P-Factor. Method.. Value. Value Comment ASPNgIT PAVFh/FA/T G. O/ /,QO (gssunE rcNsTRurTQO CONCRETE J10ti✓RLkS Soo O,G/ /.OQ MAJOR PS SUB AREA BASIN O BASIN (Ac). -CALCULATIONS L .2, 14 l 0.21� ASP//,v4T 10,9vE,V4A,7 ` D, J3 ac C p/✓c RC TE S/0 E w,v<K = O, 02 ac Sea 0.07 ac eroa O,c4�c NET C F4 c7O,P ` G• G/(0, 13 r 0. 021:0.04)1.0,0/LO,Ca O. O / /VET P FgcTOR /10(0120 _ o,zG (CaP)J0/00 po Z 0.13 00AVE/1EN7 O.Oy oc CeucRETE SiOEwgLK = O,O,Za.c ScO " O.07aC N6T C Fac>cR = O. P/(0•G9/O, 0>1 r O,O/i0 07� p,0/ 0.13 N_-7. P Fgc7OR /.G(d./3� /•U EFr _ [l-Co.o/Wi,o)7/00 95,0 0 MARCH 1991 8.15 DESIGN CRITERIA IS/22 EFFECTIVENESS CALCULATIONS PROJECT: Se vJFN_. yonEJ OFf/CE: ' B�ao-. STANDARD FORM B COMPLETED BY: T DATE: ,2g/i9R y� Erosion Control C-FactorP-Factor Method Value:. Value Cominent A.9PNA/7 P,9v£11c,v7 0.0/ l.00 (gSSilr/Ea CCA)5)RKC)6p - N-� IN lF' ry E E CJ J CcNCRETE:.SIpEwAcl(S 0.0/ /,DO Sao O, O/ /. DO MAJOR PS SUB AREA BASIN BASIN' (Ac) CALCULATIONS 8a.l4 .3 0,0'9' CONCRETE S/oEwycK = 0,0./ac OoicoluG- ` C,04 ac Net C FAC)OR O.Oe Al-,7 P FgCTCR /.O O.0, O.OIi FFf = CI (o. o/ ■ /. p)�/00 = 9 9, 0 7a 4 O.OS SD o 'Alt 7 C FAC>OR o.o/ NE7 P FAc)o)e = A Err .J. 090 EFF nvEr = 99,0 P6 > 8.2. !4 • tROJ/OA/ P/AN lS A0EmugTE MARCH 1991 8-15 DESIGN CRITERIA CONSTRUCTION SEQUENCE . ' PROJECT: Jc�sFN NcnEt Oocicc d'oa STANDARD FORM C SEQUENCE FOR 19 9 3 ONLY COMPLETED BY: T k 6� R 6 0 DATE: Z 9 H A R 9.7 Indicate by use of a bar line or symbols when erosion control measures will be installed. vajor.modifications to an approved schedule may require submitting a new. schedule for ' -approval by the City Engineer. YEAR MONTH Taut FEe Nk I Apo? I Il Ni I jr,. I ft I Ayt- Sro DcT I Nov I OVERLOT GRADING WIND EROSION CONTROL Soil Roughening Perimeter Barrier ." Additional Barriers Vegetative Methods Soil Sealant Other RAINFALL EROSION CONTROL STRUCTURAL: Sediment Trap/Basin Inlet Filters Straw Barriers Silt Fence Barriers Sand Bags Bare Soil Preparation Contour Furrows Terracing Asphalt/Concrete Paving Other VEGETATIVE: Permanent Seed Planting Fulching/sealant Temporary Seed Planting Sod Installation Nettings/Mats/Blankets Other STRUCTURES: INSTALLED BY MAINTAINED BY tVEGETATION/Y.ULCHING CONTRACTOR ' DATE SUBMITTED APPROVED BY CITY OF FORTCOLLINSON ' MARCH 1931 8-16 DESIGN CRITERIA FIGURES AND TABLES 50 1 30 1 F 20. z n1 � W 1 . z uj 1 a 0Zj 5 VN u c 3 0 U2 1 W F- • . 1 3 1 1 5 � 10111111W/­­S/IHI M MENIN oil I � , I � • ���1111� �'8i 1111110 Il I' �I��►I �IIf�Ii�tl �1������t� 1 1 .2 .3 •.5 1 2 3 5 10 20 VELOCITY IN FEET PER SECOND 1 . FIGURE 3-2. ESTIMATE OF AVERAGE FLOW VELOCITY FOR 1 USE WITH THE RATIONAL FORMULA. 1 *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.. 1 URBAN DRAINAGE & FLOOD CONTROL DISTRICT No Text /V22. O 0 m O w 0 0 w O r-4 w a� 0 41 0 O n O M 44 4J cS ro O � � Ca' 0 w 41 N � O O d H O k' O `— 00 QO d N G) DO LO d- N 00 07 0� 00 00 00 DO O O O O O O O O -4uauzq-snCp� � -OU- 10 E-H O w q W O a W a O c1Dl000 o -v v In In In In ggqqco, O rnrnrnrnoOOOoo . . . . . . O v v v V In_In In to In to v` co co co co coggqqq O q 0% m C1 C1 01 G1 C1 01 c1 C1 C1 O O 0 . . . o v-Kr vvvvvvvvv vtn to to M co g q q co g q q q q q q q c a co O r q q co01 0) m M c1 C1 m0 C% m01 C1 C% Cl C% m . . . _ O v v v v v v v v v v v v v v v v vvv v N co co q q q q co co co co co co co co OD g q q q q O Ocol VIn1D%DVr 1Drrrrrrrrrrrrggqqqq . . . . . . . . . . . . . . . . . . . . o ���vc crvvvKcqzr-;:rrlzrNr�d vvacv ,I,vv V. 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M OHI rl H--1 .CN N N N N N N N N N N N N N N N N N N NN q [0 g q q q q q c0 co q c0 q co q cD g q q q q q q q q q toClNMvto VH rrrggqC101C1C1C101000000 N 01 O 0 ri ri ri ri ri ri ri Hl ri Hi r-1 ri ri ri Hl Hi HI N N N N NN r c0 q co q q q q q q q q q q q q q q q q q q q c0 q q O vIo O MIn %oqq C10 o 0 rl H ri Hi N N N N M M M M MM . . . . . . . . . . . . . .. . . . . . . . . . . . . ry gC100000c 0c;14 44He 414 •Ir�rlr' 41ir;1;41; r r CO cO CO cO CO q CO q CO CO CO CO CO q CO CO q. q q CO CO CO CO CO In gNgH4vtorrqnG100r-irlr-,r-lr-4NNNMMMMM ri 0;q01C101C10101C101000000000000000 r r r r r r r r r r r g 0 q q q q q q q q q q co q q O o m 0 v r G1 O ri N r) co) v v In In In In o %D 1D %D r r o 1D o ri V 1Drrrrc 0*meggqqqqqqqqqqqqqq r r r r r r r r r r r r r r r r r r r r r r r r r r In C10vtDrggrrrlDV' 1DtnV'd'MMNNg110vHIG11D O. O N N N N N N N N N N N N N N N N N N N ri 4 r{ HI 0 0 .1. r r r r r r r r r r r r r r r r r r r r r r r r r r x SE�•� o.00:oo.00t0000000000000000000 O t7Et:_ 00000000000000000000000000 azt� r-iNM.Vm%Drq_rn0HINMVInI'Drwm000m0m0 W.i rl.Z. H HriHlririHlHlriNNMMv.vtn t.'AFCH 1991 8-4 DESIGN CRITERIA <r/12 ' Table 8B C-Factors and P-Factors for Evaluating EFF Values. Treatment C-Factor P-Factor BARE SOIL Packedand smooth................................................................ 1.00 1.00 Freshlydisked ............................................ :........................... 1.00 0.90 Rough irregular surface1:00 0.90 ' ............................................................ SEDIMENT BASIN/TRAP. . 1.00 0.50ol STRAW BALE BARRIER, GRAVEL FILTER, SAND BAG ........................ 1.00 0.80 ' SILT FENCE BARRIER ASPHALT/CONCRETE PAVEMENT.. ............................................ 0.01 1.00 ESTABLISHED DRY LAND (NATIVE) GRASS .......................... See Fig. 8-A 1.00 SODGRASS ............................................................................: 0.01 1.00 TEMPORARY VEGETATION/COVER CROPS .................................... 0.451.1.. 1.00 ' HYDRAULIC MULCH @ 2 TONS/ACRE........................................... 0.10"1 1.00 SOILSEALANT....................................................................0.01-0.60"' 1.00 ' EROSION CONTROL MATS/BLANKETS............................................ 0.10 1.00 GRAVEL MULCH Mulch shall consist of gravel having a diameter of approximately 1/4" to 1 1/2" and applied at a rate of at least 135 tonslacre..............0.05 1.00 HAY OR STRAW DRY MULCH After planting grass seed, apply mulch at a rate of 2 tons/acre (minimum) and adequately anchor, tack or crimp material into the soil. Slope (°h) ' 6 . to 10................. :........................................................... 0.06 1.00 11 to 15............................................................................. 0.07 1.00 16 to 20.............................................................................0.11 1.00 ' 21 to 25............................................................................. 0.14 1.00 25 to 33.............................................................................0.17 1.00 > 33........................................................................... 0.20 1.00 ' NOTE: Use of outer C-Factor or P-Factor values reponed in lujis table must be substantiated by documentation. (1) Must be constructed as the first step in overlot grading. (2) Assumes planting by dates identified in Table 11-4, thus dry or hydraulic mulches are not required. ') (3) Hydraulic mulches shall be used only between March 15 and Idiay 15 unless irrigated. (4) Value used must be substantiated, by documentation. 1 ' MARCH 1991 - 8 6 DESIGN CRITERIA Table 8-13 C-Factors and P-Factors for Evaluating EFF Values (continued from previous page). Treatment. C-Factor P-Factor ' CONTOUR.FURROWED SURFACE Must be maintained throughout the construction period, otherwise P-Factor = 1.00. Maximum length refers to the down slope length. Basin Maximum Slope Length M (feet) 1 to 2 00.........................................................................1.00 0.50 ' 3 to 5 00. ....1.00 3 0.0 6 to 8 200........................................ .1.00 0.50 9 to 12 120..........................................................................1.00 0.60 13 to 16 0..........................................................................1.00 0.80 . 20. GO . ... 1.00 � 17 to 6 0.0 > 20. 50.......................................................................... 1.00 0.90 TERRACING ' Must contain 10-year runoff volumes, without overflowing, as determined by applicable hydrologic methods, otherwise P-Factor = 1.00. ' Basin Slope M 1 to 2.................................................................................... 1.00 0.12 3 to 8.....................................................................................1.00 0.12 ' 9 to 12. .00 0.1 13 to 16..................................................................................... 1.00 0.14 17 "to 20.....................................................................................1.00 0.16 > 20..................................................................................... 1.00 0.18 ' NOTE: Use of o-d)er C-Factor or P-Factor values reported in this table must be substantiated by documentation. 1 ' MARCH 1991 8.7 DESIGN CRITERIA LEGEND erNNo+r : "Notts eAWNERS MPNLT FALL- . --- � elklwl B IdTgMI TD I'M/L. L' W ICp LPGf9 PLAN PROR»ED la+Tdp ______—D�jIN LINE 0.09 -- M51N AREA iALFIL6i j © CIRA N MINT 9°rr-NOT PROMeED ELtVATId I D: W -_ coN¢Rere wAi.R 9 we _ I = All INPLON LJRp i BIIr2R I Q �¢p( IX1TFLaW LNt>�6vrTER ~ LL�Y J Vu n6 kw:e�R V ' O xN(.I :.w G11V 611 vcF F yIr rNl V 8N1� MM1IAO, Q N Vs' t/ 1 n/'xF1L ER.T���1 BIO'Ew. ' la W"Ltal Nf NOT 40 If 00a'C,0 MAL VU ILL FVw Lwc— I'm rW'rim -'-h— EILVAq' 10 f D'rN - M u �kY L F SECTIOMB-6 'Oa' TVGH RKK SY'N> "ACED, Y4RL. [WT IRA 9WM4pJ R!ENTW �W/TM[fGTD INi6Af IMEGpzo 0.uD CMLT CEWy` IM Lore. 1 � S FEE T O UsL_ j 1\ Ihm H4.E DRIWo _r JL r IMo yR¢. MTE I-' -- -.- M1aNILYL CROSS PAN DETAIL SECTION A —A EAST PARKING LOT PIPE OUTLET DETAIL i«°'"R®'z - E.1F Yw,� s soli 9' 0 ♦ - _ iNi�nuuo' mot r 3 0 NO 13 1 112 e +� r INFLOW CURB S OUTiER 1 I—r--F--�—T-��-asIt h ��{e'w'LL ("+=v. xar "[Waco xsrO s[tnoxl CONCRETE PAN i. .{—"6'�'n14'e��rM'E a-R. ITT j_V2: I �'- 400.Vg CU t.W MrtJ DETENTION POND OUTLET DETAILS OUTFAII CURB N GUTTER REMF. NOT AE371 EO IN 9TD SECTION OF$ ACK Danz;P OE90Nm acerED lee Engineering C"uRonfe 111 614 OW2 YNA YLL1um�]� iW Ir. 16N M..SW 1]®, ik.9 YilYlMIe9 Po. M.r l6] REVISION DESCRIPTION MPF�IVCD NEW PPWECT NO I W/4412-9122 �tx-Fol w%PAR -RAW F 5 I E TK GRWTILN MIT $ ORDNLoer•" WXHwi. a r NOTE RUWFF FRCN EVEpfI.IN TIT EE ft t W F"NGH DRAIN, %FL PLANS M Ar(JIITFGT roR 2TIEL9[F OVIN. IN�If hPPKIFE - � '_ PROPOSED / OFFICE BUILDING TO 0.]8 ❑ ToANE'�_/ II 3 . \0.0e \ I SITE PLAN is-fl0 Or a RUN ARM I— -- ILIA Lj IHGV UlSU�lO3UL �'Dl h2 A III I It IV' AROUND. ILL ANN it RADIO, IAI"MOCl 1; OF FLAT .11, 01,111, PATIMMATT 'Sit ANCRECAUR VETO IF APPLIED AT A MINIMUM MADE OF 125 FROMES PON ACRE nn. LNLBdkIll toTUE wPROVIDE AND wu TAILIFEEM AM RIM No ,. oe cu 2, FAA OPECTIFFER OF "Elf PIANO FULEFORM IN THE MITI or rin III ITT EVEN IVEtCArLnj w'. w' IUY'IN451'ILII1'lItlQ1.0G1 .UTI AIR, U. AN 1.11 AN III AREA Not, MAN 1.11 11-i..r NATO ": i _: UTUKE � N+AEe lI -�--TPMI4WtY _�.tL er.sxlNE I6rNgATµN DIaH —. - DETENTION MIND I I Q IF All PIR AAlti 1Nj T WO ORIN"erM MNRNJLE(BM.0:1A2j d1 PAN I xslw rr s la�ieo YMRIWY LANE. LINE" TL VwIMtt MN) A wa047 crf LLnv3TR1GT COIi'lill FAu. IMTCH q,IgPRIp rs/,m Nwiv U xFyf+ TIl K [xt iNL7 Scale V = EG' NLD ^--10 a A b - W I cane OFFICE BUILDING FOR JENSEN HOMES I DRAINAGE AND EROSION CONTROL PLAN 4828 SOUTH COLLEGE AVE. FORT COLLINS, COLOBADO -v