Loading...
HomeMy WebLinkAbout14 - Design Report - Great Northern Business Park (Griffin Drive) - Stormwater I ENGINEERING ENESIS CONSULTING PLANNING J NGINEER( DESIGN NGN INC 204 N.1111 Ave. BOZEMAN,MT 59715 406-581-3319 �ge 204AVENUE, o Storm Water Management Design Report Great Northern Business Park 608-614 West Griffin Drive Bozeman, Montana APRIL 2014 Prepared By: Genesis Engineering, Inc. GEI Project#: 1086.001.040 Prepared For: Longshot Equity, LLC PO Box 5005 Bozeman, MT 59717 204 N. 111h Ave., Bozeman, MT 59715 Cell:(406)581-3319 www.q-a-i.net `ate Page 1 of 8 H:\1086\001\DOCS\Design\Storm\StormwaterDR.doc SIS NGINEERING, INC Storm Water Management Design Report Table of Contents I. Project Background.............................................................................................................. 4 1. Introduction............................................................................................................................... 4 2. Soil and Groundwater.............................................................................................................. 4 3. Land Use..................................................................................................................................... 4 II. Existing Conditions.................................................................................................................. 4 1. Drainage Basins and Pre-Development Peak Flows............................................................ 4 III. Proposed Drainage Plan and Post-Development Peak Flows........................................ 5 1. Major Drainage System........................................................................................................... 6 2. Minor Drainage System........................................................................................................... 6 3. Maintenance............................................................................................................................. 7 IV. Conclusion................................................................................................................................ 7 List of Tables Table 1. Estimated Pre-Development Peak Flows................................................................................... 5 Table 2. Estimated Capacity of Existing Drainage Facilities................................................................... 5 Table 3. Estimated Post-Development Peak Flows................................................................................. 5 Table4. Required Pond Volumes.............................................................................................................. 6 Table 5. Proposed Drainage Facility Capacity.......................................................................................... 6 Appendix A—Calculations Grading and Drainage Exhibits Pre/Post Development Drainage Basin Flows Existing East Ditch Modeling Existing 36"CMP Storm Pond Calculations Valley Gutter Modeling Pipe Flow Modeling Proposed East Ditch Modeling Outlet Structure Calculations 204 N. 11`h Ave., Bozeman, MT 59715 Cell: (406)581-3319 www.q-a-i.net rid' Page 2 of 8 H:\1086\001\DOCS\Design\Storm\StormwaterDR.doc i SIS NGINEERING,INC yevw.va.✓dfr.— List of References City of Bozeman Design Standards and Specifications Policy, March 2004, and all addenda. 204 N. 11"Ave.,Bozeman,MT 59715 Cell:(406)581-3319 www.q-a-i.net ,� Page 3 of 8 H:\1086\001\DOCS\Design\Storm\StormwaterDR.doc (s SIS kING,INC I. Project Background Introduction The Great Northern Business Park consists of 14 units of warehouse/office on two existing lots of the McChesney Industrial Park Subdivision. The two lots cover approximately 1.74 acres in Section 1,T2S, R5E, PMM in Bozeman, Gallatin County, Montana. The property lies immediately south of West Griffin Drive and about 350'east of North 7`h Avenue. I 7 r 10/ ,.• ( ; X\u Iaerc 11;�i- •�I h I PROJECT ARFA, PF� This report outlines the storm water analysis conducted for the BASIN N : , , (2 5 ACRES) L �.' �; BASIN A2 i site and describes the storm water drainage and management _ (,.7sncREs) / facilities required for Great Northern Business Park by state �� ���— `� •; • �•• `` �\ and local regulations. The storm water plan follows the design �,\ = _ I T. standards set forth by the City of Bozeman in Design Standards -__. = —and Specifications Policy,March 2004 and three subsequent �— bm addenda. I � '� vs- Soil and Groundwater 17 'sr The NRCS Soil Survey identifies one major soil types on the site: /pASINA i ••:�s ; I/� 1(206 ACRES) Blackdog-Quagle silt loams(450C).These soils belong to I ' _ hydrologic soil group B as they are comprised primarily of Ix ,A769AT 11 / fafigrou�� loams and silt loams with moderately high saturated hydraulic conductivity. ; j 1' - I I •I \ A geotechnical investigation by C&H Engineering on January1 -� 15, 2014, did not mention finding any groundwater in the roughly seven foot deep test pits. e>3�* Land UseMCC The pre-development land use on the site was vacant lots from the original McChesney Industrial Park Subdivision in 1978. The proposed use is for 14 warehouse/office condo units. it MA/V St �rr,7w`If ii€(Iffillf Figure 1—Vicinity map of basin II. Existing Conditions The Great Northern Business Park lies south of Griffin Drive with an unnamed ditch on the east boundary.The land slopes generally to the northeast at a grade of approximately 5%. The high point of the property is located on the west side of the property,with slightly higher ground continuing through the west side of the property. This natural feature shunts pre-development runoff overland into the unnamed ditch to the east. Drainage Basins and Pre-development Peak Flows Genesis identified one drainage basin and one sub-area offsite and one drainage basin onsite as shown on drawings GD1, in Appendix A. The 206 acre off-site basin (Off-site)stretches from the outfall at the north property line for approximately 7,300 feet to the south,ending approximately at Main Street. Another contributing subarea was identified to the west of the property that drains along the south boundary of the subject property. Estimates of runoff and their respective calculations for the existing and subareas were completed using the Modified Rational Method. Our large basin model uses a runoff coefficient of 0.55 which represent the typical ground cover we see today and the smaller basins use a C=0.20. Given the size of the existing offsite contributing basin, linear regression of existing basins and SCS TR-20 graphical peak methods (CN=75)were also used to analyze runoff generated from the 206 acre offsite basin. Genesis looked at many 204 N. 11`h Ave., Bozeman,MT 59715 Cell:(406)581-3319 www.q-e-i.net Page 4 of 8 H:\1086\001\DOCS\Design\Storm\StormwaterDR.doc G'1106 a�oJov,SrmAaAofC�m�i.,m storm events such as the 10-year, 25-year and 100-yr in the analysis of the existing storm water conveyance facilities within the site. A summary of estimated pre-development peak runoff rates as well as existing drainage facility capacities can be found in Table 1 and 2. Detailed calculations are available in Appendix A. Table 1. Estimated Pre-Development Peak Flows(see GD-1) Sub Area Description Area Tc Q10 Q25 Q300 (acres) (min) (cfs) (cfs) (cfs) A Offsite Basin-Rational 206 115 47 58 74 A Offsite Basin—SCS TR-20 206 115 17 34 54 Al Offsite Sub-area 2.5 15 0.8 1.0 1.3 A2 Onsite Basin 1.75 10 0.7 0.9 1.2 Table 2. Existing Drainage Facility Capacity Description Contributing Depth Slope Q10pst Q25pst Q100pst Facility Cap Passes Subareas (ft) W (cfs) (cfs) (cfs) (cfs) 100-YR Existing east ditch channel A 1.5 0.6 17 34 54 57* Y Existing east ditch channel A 3.0 0.6 17 34 54 220* y Existing 36"CMP @ Griffin A 2.4 0.7 17 34 54 54** Y *Capacity measured with a normal depth as described in the table. **Capacity is measured using the water surface elevation of 4702.68 which equals the overflow elevation onto Gilkerson. III. Proposed Drainage Plan and Estimated Post-Development Peak Flows The proposed drainage plan shall build off of the existing drainage system in place. Genesis' drainage plan consists of two drainage systems. First,the major drainage system or backbone is designed to have a much higher conveyance capacity and shall convey the excess runoff from the 100-year storm without inundating any building structures. Secondly,the minor drainage system fits within the major drainage system and feed into it. The minor drainage system(s)are designed to accommodate moderate and relatively frequent storm events without inconveniencing the public. The minor system is comprised of the streets, inlets,and swales designed to convey runoff from the 25-year event, and retention or detention ponds designed for the 10-year storm event. Table 3 presents a summary of expected post-development peak flow rates passing through the proposed major subdivision. Table 3. Estimated Post-Development Peak Flows(see GD-1) Sub Area Description Area Tc Q10 Q25 Q100 (acres) (min) (cfs) (cfs) (cfs) A Offsite Basin—SCS TR-20 206 115 17 34 72* Al Offsite subarea 2.5 10 4.4 5.2 7.1 A2 Onsite subarea 1.75 10 3.1 3.6 5.0 *The remaining lands not currently developed in this 206 acre basin are modeled as developed(CN=79)for the future event. 204 N. 111h Ave., Bozeman, MT 59715 Cell:(406)581-3319 www.q-e-i.net I:i' Page 5 of 8 H:\1086\001\ROCS\Design\Storm\StormwaterDR.doc I rr jfI{ SYS NGINEERING,INC 7fie a.pf.rn�fev Srnd rS fCnmmamrnr Major Drainage System The major drainage system is comprised of the unnamed ditch on the east boundary of the subject parcel. The unnamed ditch flows into a 36" round corrugated steel culvert(CMP) under West Griffin Drive. As mentioned above,the existing 36"CMP has an estimated capacity of 54 cfs with a surface water elevation of 4702.68. Using the SCS-TR-20 method post-development 100yr flow of 72 cfs leaves 18 cfs of flow to be bypassed. The low point in the system is about 120'east of the existing 36"CMP at the intersection of Gilkerson and West Griffin. The estimated 18 cfs of bypass will flow over Gilkerson Drive at an estimated elevation of 4703.00'. The first floor elevations of the proposed buildings adjacent to the existing ditch channel are 4708.00'& 4708.65',which are more than 5 feet above the ultimate 100-year Base Flood Elevation of 4703.00'. Our computer modeling indicates that the existing stream corridor and overflow system in place has adequate capacity to convey the entire 100-year event without inundating any existing building structures south of Griffin. Site grading onsite shall be completed so that runoff resulting from storm events between the 25-year and 100-year will flow through parking lots and down conveyance swales without inundating any structures or causing significant erosion. Minor Drainage System The proposed minor drainage system includes interior parking lot sheet flow into a valley gutter to direct runoff into the detention pond. The detention pond located at the northeast corner will attenuate runoff generated by the new site development(subarea A2).The design storm event is the 10-year event with discharge from the detention pond limited to the 10-year pre-development peak flow rate. The City of Bozeman Design Standards and Specifications Policy requires that detention pond volume be adequate to accommodate the difference in peak runoff between the pre-development and post-development design storm of 10 years,while retention ponds must contain the entire 10-year 2-hour design storm volume. All pond side slopes will be sloped to finished grade at 4H:1V. The detention ponds shall have an outlet structure with a weir plate sized to convey only the 10-year pre-development flow rate with larger storms using the pond overflow down into the existing ditch channel. Table 4 shows the calculated pond volumes. Table 4. Pond Volumes Pond Type Location Contributing Q10Pre Q25post Qrelease Volume Subarea (cfs) (cfs) (cfs) (cft) 1 Detention NE Corner A2 0.7 3.6 0.7 1,556 The valley gutter in the parking lot will direct the runoff to the detention pond. The valley gutter will convey an estimated 18 cfs before inundating the sidewalk in front of the building,which is almost 3 times the 100 year flow rate of subarea A-2. The swale/culvert along the south end of the property is sized to convey the estimated post development flow from the south and west(subarea Al). The 15"A-2000 culvert has an estimated capacity of 5.9 cfs which exceeds the 25 year post development flow of subarea A of 5.2 cfs. Modeling results for the valley gutter and culvert are shown below in Table 5 and included in Appendix A. Table 5. Proposed Drainage Facility Capacity Description Contributing Depth Slope Q10Pst Q25pst Q100pst Capacity Passes Subareas (ft) (%) (cfs) (cfs) (cfs) (cfs) Design Storm Valley Gutter A2 0.79 0.5 1.5 8.8 12.1 18 Y 15"A-2000 Al 1.25 3.5 0.8 5.2 7.1 5.9 Y* Modified East Ditch A 4.0 0.65 17 34 72 132 Y *Culvert design storm is 25-year. 204 N. 111h Ave., Bozeman,MT 59715 Cell: (406)581-3319 www.g-e-i.net Page 6 of 8 H:\1086\001\DOCS\Design\Storm\StormwaterDR.doc � f NGINEERING,INC '— 4Fe Enginnmnfo�'rm.Uan�rlef(,'nmmitmmt Maintenance Regular maintenance of storm water facilities is necessary for proper functioning of the drainage system. In general, regular mowing of any grass swales and storage ponds and unclogging of inlets and outlet works will be required to prevent standing water, clogging,and the growth of weeds and wetland plants. More substantial maintenance,such as sediment removal with heavy equipment, may be required in coming decades to restore detention pond volume. All maintenance and repair should be prioritized and scheduled in advance. Inlets&pipes should be visually inspected yearly. Typical maintenance items include removing obstructions,cleaning and flushing pipes, mowing grass and weeds,tree maintenance to prevent limbs from falling and blocking swales,and establishing groundcover on bare ground. IV. Conclusion Storm water analysis and calculations indicate that the proposed storm water management plan for the Great Northern Business Park is adequate to safely convey the 10-year 2-hour, 25-year,and 100-year storm events and satisfy state and local regulations. The existing backwater effect or water surface elevation caused by existing 36" CMP under Griffin is not significantly increased as the result of this proposed development or the modified ditch channel. 204 N. 11"Ave.,Bozeman,MT 59715 Cell: (406)581-3319 www.q-a-i.net (iZ Page 7 of 8 H:\1086\001\DOCS\Design\Storm\stormwaterDR.doc SIS NGINEERING,INC 1 'IRr ArAinnin�nfa Nru,,SmnAerCnfCnmmiimrnr Appendix A Calculations 204 N. 11th Ave.,Bozeman,MT 59715 Cell:(406)581-3319 www.q-a-i.net �i' Page 8 of 8 H:\1086\001\DOCS\Design\Storm\StormwaterDR.doc Tr4 ; le- PROJECT AREA BASIN Al ?.5 ACRES ) BASIN A2 .' \ 1 (1.75 ACRES) 1 . 6 �, l \"N 01 re \\ —BACKWATER WEST GRIFFIN DRIVE —J J DETENTION OVERFLOW lose 715 `� BACKWATER W ■ r.._ ! I 1/T _'11 `;r/ \! 1 CS 1+00 \\ \ FLOODLINE Y lt\ • �'— _ '\ \\ \\ _ FFE=4703.68' U' go 04, i w ■ `7 ! .J 1 _ I— ' i / •w• 6 � __ ; UNNAMED DITCH BASIN A .w ' z f 1+z5 • , , (206 ACRES) _ _ ' ; /' VA LE T FFE=4704.16' 47 6 V T1T I ■ ■ r / � � r ��_ �__�� � � � r i � � vI ' �� I v ;, f`ai ground ■ 1 ;; 12+50 MCII F ) / / �/ d; \ \,T51'AL2001 . /r I 1 I �; FFE=4706.03' i C�� i\...,9 .�� i r i -; WE$r zt ENE' � \\ 1 y.., FFE=4706.20' •i I 1 w i • • � `�`\�\:\\.�\ !.--' -` r • w i \i �`��``�` \` \\ \ \\` i ' `\ `\�;; : BASIN A2 1.75 ACRES ,rr -- / � �• :, :�; FS, BASIN Al O ,��� i■i" ��`� (2.5 ACRES) 9X GRAPHIC SCALE In !•..t•.':.. '. l,�y1'• �Y 5U o cxnrtuo SCALE 1ixtar) r., �. (M"In) 1 bnb- 500 iti ,' :'•.. ,r I imb- 60 IL 11"X17':111100 ft VERIFY SCALE REVISIONS DRAWN BY:JRM PROJECT NUMBER :" THESEPRINTS MAY 9E NO. DESCRIPTION DATE BY CHK'D.BY:CMW GREAT NORTHERN BUSINESS PARK 10e6.001 REDUCED.LINERELOw M CRIGRES DNEWIN ON STORM WATER REPORT SHEET NUMBER CR URES O E INCH. ERgineenRg APPR.BY:CMW BOZEMAN MT NESISCDnsulfing 204 N.111h Ave. —ti INCDesign Bozeman,MT 59715 DATE:04/2014 DRAWING NUMBER ,.y NGWEERING, f Plaoning Phane:(406)581-3319 D.A.REVIEW NODIF SCALE ACCORDINGLY - BY: STORM WATER BASINS GD-1 H:\1086\001\ACAD\SheelslSTORM-baslns.dwg Plotted by Chris waste on 4/29120145:05 PM ! g6t®t innin o aiVrw Slandardo Commitment COWRllC GENESIS ENGINEERING.INC.2014 DATE: GEI#: 1086.001 DATE: 4/28/2014 ENGINEER: CMW Basin A-10YR MODIFIED RATIONAL METHOD Qp=CIA PRE-DEVELOPMENT RAINFALL FREQ= 10 YR(DURATION=1) i=A*(Tc/60)_e (CITY OF BOZEMAN) BASIN AREA PRE= 206 AC STORM EVENT STORM i COEFF INTENSITY YR A 8 IN/HR PRE-DEVTc= 115.0 MIN 2 0.36 0.6 0.24 5 0.52 0.64 0.34 PRE-DEV C= 0.55 10 0.64 0.66 0.42 25 0.78 0.64 0.51 STORM A= 0.64 50 0.92 0.66 0.60 B= 0.66 100 1.01 0.67 0.65 STORM INTENSITY= 0.42 IN/HR PRE-DEV Qp= 47.20 CFS POST-DEVELOPMENT BASIN AREA POST= 206.00 AC POST-DEV Tc= 115.0 MIN POST-DEV C= 0.55 STORM INTENSITY= 0.42 IN/HR POST-DEV Qp= 47.20 CFS H:\1086\001\DOCS\Design\StormW-BASIN-10YR.xls 1 OF 1 PRINTED: 4/29/2014 GEI#: 1086,001 DATE: 4/28/2014 ENGINEER: CMW BASIN A- 25YR MODIFIED RATIONAL METHOD Qp=CiA PRE-DEVELOPMENT RAINFALL FREQ= 25 YR(DURATION=1) i=A*(Tc/60).a (CITY OF BOZEMAN) BASIN AREA PRE= 206 AC STORM EVENT STORM i COEFF INTENSITY YR A 8 IN HR PRE-DEVTc= 115.0 MIN 2 0.36 0.6 0.24 S 0.52 0.64 0.34 PRE-DEV C= 0.55 10 0.64 0.66 0.42 25 0.78 0.64 0.51 STORM A= 0.78 SO 0.92 0.66 0.60 B= 0.64 100 1.01 0.67 0.65 STORM INTENSITY= 0.51 IN/HR PRE-DEV Qp= 58.28 CFS POST-DEVELOPMENT BASIN AREA POST= 206.00 AC POST-DEVTc= 115.0 MIN POST-DEV C= O.SS STORM INTENSITY= 0.51 IN/HR POST-DEV Qp= 58.28 CFS H:\1086\001\DOCS\Design\Storm\A-BASIN-25YR.xls 1 OF 1 PRINTED: 4/29/2014 GEI#: 1086.001 DATE: 4/28/2014 ENGINEER: CMW BASIN A-SOYr MODIFIED RATIONAL METHOD Qp=CIA PRE-DEVELOPMENT RAINFALL FREQ= 50 YR(DURATION=1) i=A*(Tc/60)_e (CITY OF BOZEMAN) BASIN AREA PRE= 206 AC STORM EVENT STORM i COEFF INTENSITY YR A B IN HR PRE-DEV Tc= 115.0 MIN 2 0.36 0.6 0.24 5 0.52 0.64 0.34 PRE-DEV C= 0.55 10 0.64 0.66 0.42 25 0.78 0.64 0.51 STORM A= 0.92 50 0.92 0.66 0.60 B= 0.66 100 1.01 0.67 0.65 STORM INTENSITY= 0.60 IN/HR PRE-DEV Qp= 67.85 CFS POST-DEVELOPMENT BASIN AREA PRE= 206 AC POST-DEV Tc= 115.0 MIN POST-DEV C= 0.55 STORM INTENSITY= 0.60 IN/HR POST-DEV Qp= 67.85 CFS H:\1086\001\DOCS\Design\Storm\A-BASIN-50YR.As 1 OF 1 PRINTED: 4/29/2014 GEI#: 1086.001 DATE: 4/28/2014 ENGINEER: CMW Basin A MODIFIED RATIONAL METHOD Qp=CiA PRE-DEVELOPMENT RAINFALL FREQ= 100 YR(DURATION=1) i=A`(Tc/60).e (CITY OF BOZEMAN) BASIN AREA PRE= 206 AC STORM EVENT STORM i COEFF INTENSITY YR A B IN HR PRE-DEV Tc= 115.0 MIN 2 0.36 0.6 0.24 5 0.52 0.64 0.34 PRE-DEV C= 0.55 10 0.64 0.66 0.42 25 0.78 0.64 0.51 STORM A= 1.01 50 0.92 0.66 0.60 B= 0.67 100 1.01 0.67 0.65 STORM INTENSITY= 0.65 IN/HR PRE-DEV Qp= 74.00 CFS POST-DEVELOPMENT BASIN AREA PRE= 206 AC POST-DEV Tc= 115.0 MIN POST-DEV C= 0.5 STORM INTENSITY= 0.65 IN/HR POST-DEV Qp= 67.27 CFS H:\1086\001\DOCS\Design\Storm\A-BASIN-100YR.xls 1 OF 1 PRINTED. 4/29/2014 McChesney Type 11 24-hr Bozeman -10 Yr Rainfall=1.90" Prepared by {enter your company name here} Printed 4/29/2014 HydroCADO 9.10 s/n 07079 ©2010 HydroCAD Software Solutions LLC Page 1 Summary for Subcatchment 1S: PreDeveopment Runoff = 16.72 cfs @ 13.56 hrs, Volume= 4.611 af, Depth> 0.27" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr Bozeman -10 Yr Rainfall=1.90" Area (ac) CN Description 206.000 75 50-75% Grass cover, Fair, HSG B 206.000 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 115.0 8,252 1.20 Direct Entry, My own Tc Subcatchment 1S: PreDeveopment Hydrograph 16_ 16.72 Cfs �Runoff 17 Type II 24-hr Bozeman -10 Yr 16: 15_ Rainfall=1.90" 14 Runoff Area=206.000 ac 1 3 Runoff Volume=4.611 of 12- 11. Runoff Depth>0.27" 10= Flow Length=8,252' 9- Tc=115.0 min LL 8_ i 7- CN=75 i 6- 5= i 4- 3= 2= 1- 0- 6 fi 8 9 10 1,1 12 13 14 15 16 17 18 19 20 Time (hours) McChesney Type/1 24-hr Bozeman -25 Yr Rainfall=2.40" Prepared by {enter your company name here} Printed 4/29/2014 HydroCAD®9.10 s/n 07079 ©2010 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment 1S: PreDeveopment Runoff = 33.74 cfs @ 13.45 hrs, Volume= 8.466 af, Depth> 0.49" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr Bozeman -25 Yr Rainfall=2.40" Area (ac) CN Description 206.000 75 50-75% Grass cover, Fair, HSG B 206.000 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 115.0 8,252 1.20 Direct Entry, My own Tc Subcatchment 1S: PreDeveopment Hydrograph 36= 33.74 cfs Runoff 34- Type II 24-hr Bozeman -25 Yr 32= 30= Rainfall=2.40" 28- Runoff Area=206.000 ac 26= Runoff Volume=8.466 of 24- 22 Runoff Depth>0.49" 20 Flow Length=8,252' LL 18 Tc=115.0 min 16- 14= CN=75 12= 10= 8= 6= 4- 2= 0- 5 fi 7 8 9 10 11 12 13 14 15 16 .17 .18 19 20 Time (hours) McChesney Type 11 24-hr Bozeman -100 Yr Rainfall=2.90" Prepared by {enter your company name here} Printed 4/29/2014 HydroCAD®9.10 s/n 07079 ©2010 HydroCAD Software Solutions LLC Page 2 Summary for Subcatchment 1S: PreDeveopment Runoff = 54.61 cfs @ 13.42 hrs, Volume= 13.027 af, Depth> 0.76" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr Bozeman -100 Yr Rainfall=2.90" Area (ac) CN Description 206.000 75 50-75% Grass cover, Fair, HSG B 206.000 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 115.0 8,252 1.20 Direct Entry, My own Tc Subcatchment 1S: PreDeveopment Hydrograph 60- p Runoff 54.61 cfs 1. 55 Type II 24-hr Bozeman -100 Yr so= Rainfall=2.90" 45- Runoff Area=206.000 ac 40_ Runoff Volume=13.027 of Runoff Depth>0.76" 35- Flow Length=8,252' 3 30 Tc=115.0 min 0 LL 25 CN=75 20- 15- 10- i 5- 0- 5 fi 7 B 9 10 1,1 12 .13 14 15' 16 17 19 19 20 Time (hours) McChesney Type 11 24-hrBozeman -100 Yr Rainfall=2.90" Prepared by {enter your company name here) Printed 4/29/2014 HydroCAD®9.10 s/n 07079 ©2010 HydroCAD Software Solutions LLC Page 1 Summary for Subcatchment 1S: PreDeveopment Runoff = 71.60 cfs @ 13.41 hrs, Volume= 16.497 af, Depth> 0.96" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr Bozeman -100 Yr Rainfall=2.90" Area (ac) CN Description 206.000 79 50-75% Grass cover, Fair, HSG B 206.000 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 115.0 8,252 1.20 Direct Entry, My own Tc Subcatchment 1S: PreDeveopment Hydrograph 80 p Runoff 75- 71.60 cfs 70- Type II 24-hr Bozeman -100 Yr 65 Rainfall=2.90" 60= Runoff Area=206.000 ac 55= � Runoff Volume=16.497 of 50- Runoff Depth>0.96" 45- Flow Length=8,252' 3 40= LL 35: Tc=115.0 min 30- CN=79 25= 20= 15= 10= 5= 0- b fi 8 9 10 1,1 12 13 .14 15 16 17 18 19 20 Time (hours) GEI#: 1086.001.040 DATE: 4/17/2014 ENGINEER: Chris Wasia I Subarea Al-10 yr � �( MODIFIED RATIONAL METHOD 'I NGINEER[NG, INC Qp=CIA `J PRE-DEVELOPMENT RAINFALL FREQ= 10 YR(DURATION=1) i=A"(Tc/60)-B (CITY OF BOZEMAN) BASIN AREA PRE= 2.5 AC STORM EVENT STORM i COEFF INTENSITY YR A B IN/HR PRE-DEVTc= 15.0 MIN 2 0.36 0.6 0.83 5 0.52 0.64 1.26 PRE-DEV C= 0.20 10 0.64 0.66 1.60 25 0.78 0.64 1.89 STORM A= 0.64 50 0.92 0.66 2.30 B= 0.66 100 1.01 0.67 2.56 STORM INTENSITY= 1.60 IN/HR PRE-DEV Qp= 0.80 CFS POST-DEVELOPMENT BASIN AREA PRE= 2.5 AC POST-DEVTc= 10.0 MIN POST-DEV C= 0.85 STORM INTENSITY= 2.09 IN/HR POST-DEV Qp= 4.44 CFS H:\1086\001\DOCS\Design\Storm\subarea Al-10.x1s 1 OF 2 PRINTED: 4/29/2014 GEI#: 1086.001.040 DATE: 4/17/2014 ENGINEER: Chris Wasia Subarea Al-25 yr S I 1 MODIFIED RATIONAL METHOD NG[NEER[NG, INC Qp=CiA 7l)•1 11 II I AvI' He»liae.•.,^.tT�inll'i 40fi.SA1331 PRE-DEVELOPMENT RAINFALL FREQ= 25 YR(DURATION=1) i=A*(Tc/60)-B (CITY OF BOZEMAN) BASIN AREA PRE= 2.5 AC STORM EVENT STORM i COEFF INTENSITY YR A B IN/HR PRE-DEVTc= 15.0 MIN 2 0.36 0.6 0.83 5 0.52 0.64 1.26 PRE-DEV C= 0.20 10 0.64 0.66 1.60 25 0.78 0.64 1.89 STORM A= 0.78 50 0.92 0.66 2.30 B= 0.64 100 1.01 0.67 2.56 STORM INTENSITY= 1.89 IN/HR PRE-DEV Qp= 0.95 CFS POST-DEVELOPMENT BASIN AREA PRE= 2.5 AC POST-DEVTc= 10.0 MIN POST-DEV C= 0.85 STORM INTENSITY= 2.46 IN/HR POST-DEV Qp= 5.22 CFS H:\1086\001\DOGS\Design\Storm\subarea Al-25.xis 1 OF 2 PRINTED: 4/29/2014 GEI#: 1086,001.040 DATE: 4/17/2014 ENGINEER: Chris Wasia p Subarea Al N S A S MODIFIED RATIONAL METHOD NGINEERING, INC: Qp=CIA 204 P1 IITIi A11 •dn'..`d i III'I I 4G6 SF31:i.ID PRE-DEVELOPMENT RAINFALL FREQ= 100 YR(DURATION=1) i=A*(Tc/60)_e (CITY OF BOZEMAN) BASIN AREA PRE= 2.5 AC STORM EVENT STORM i COEFF INTENSITY YR A B IN/HR PRE-DEV Tc= 15.0 MIN 2 0.36 0.6 0.83 5 0.52 0.64 1.26 PRE-DEV C= 0.20 10 0.64 0.66 1.60 25 0.78 0.64 1.89 STORM A= 1.01 50 0.92 0.66 2.30 B= 0.67 100 1.01 0.67 2.56 STORM INTENSITY= 2.56 IN/HR PRE-DEV Qp= 1.28 CFS POST-DEVELOPMENT BASIN AREA PRE= 2.5 AC POST-DEVTc= 10.0 MIN POST-DEV C= 0.85 STORM INTENSITY= 3.35 IN/HR POST-DEV Qp= 7.13 CFS H:\1086\001\DOGS\Design\Storm\subarea Al-100.x1s 1 OF 2 PRINTED: 4/29/2014 GEI#: 1086.001.040 DATE: 4/17/2014 ENGINEER: Chris Wasia l Subarea A2 - 10 yr S I S MODIFIED RATIONAL METHOD NGINEERING, INC Qp=CiA Zort IIIIII'A,I Hnn•.I:...G1�SD115 4qG`FI_i3I PRE-DEVELOPMENT RAINFALL FREQ= 10 YR(DURATION=1) i=A*(Tc/60)_B (CITY OF BOZEMAN) BASIN AREA PRE= 1.75 AC STORM EVENT STORM i COEFF INTENSITY YR A B N/HR PRE-DEVTc= 10.0 MIN 2 0.36 0.6 1.05 5 0.52 0.64 1.64 PRE-DEV C= 0.20 10 0.64 0.66 2.09 25 0.78 0.64 2.46 STORM A= 0.64 50 0.92 0.66 3.00 B= 0.66 100 1.01 0.67 3.35 STORM INTENSITY= 2.09 IN/HR PRE-DEV Qp= 0.73 CFS POST-DEVELOPMENT BASIN AREA PRE= 1.75 AC POST-DEV Tc= 10.0 MIN POST-DEV C= 0.85 STORM INTENSITY= 2.09 IN/HR POST-DEV Qp= 3.11 CFS H:\1086\001\DOGS\Design\Storm\subarea A2-10.xls 1 OF 1 PRINTED: 4/29/2014 GEI4: 1086.001.040 DATE: 4/17/2014 ENGINEER: Chris Wasia Subarea A2 - 25 yr MODIFIED RATIONAL METHOD NGINEERING, INC Qp=CiA 2o,i ri nn✓.v. r+nn+:,•,.vrssr;ir, ncn sr,i:,.�c, PRE-DEVELOPMENT RAINFALL FREQ= 25 YR(DURATION=1) i=A*(Tc/60)_B (CITY OF BOZEMAN) BASIN AREA PRE= 1.75 AC STORM EVENT STORM i COEFF INTENSITY YR A B IN/HR PRE-DEV Tc= 10.0 MIN 2 0.36 0.6 1.05 5 0.52 0.64 1.64 PRE-DEV C= 0.20 10 0.64 0.66 2.09 25 0.78 0.64 2.46 STORM A= 0.78 50 0.92 0.66 3.00 B= 0.64 100 1.01 0.67 3.35 STORM INTENSITY= 2.46 IN/HR PRE-DEV Qp= 0.86 CFS POST-DEVELOPMENT BASIN AREA PRE= 1.75 AC POST-DEV Tc= 10.0 MIN POST-DEV C= 0.85 STORM INTENSITY= 2.46 IN/HR POST-DEV Qp= 3.65 CFS H:\1086\001\DOGS\Design\Storm\subarea A2-25.xls 1 OF 1 PRINTED: 4/29/2014 GEIH: 1086.001.040 DATE: 4/17/2014 ENGINEER: Chris Wasia Subarea A-2 - 100 yr S I S MODIFIED RATIONAL METHOD NGINEERING, INC Qp=CIA :OAP! I I AVi Fil—m.nr.,M!5911(5 ACii=ei 3.91T, PRE-DEVELOPMENT RAINFALL FREQ= 100 YR(DURATION=1) i=A*(Tc/60).B (CITY OF BOZEMAN) BASIN AREA PRE= 1.75 AC STORM EVENT STORM i COEFF INTENSITY YR A B IN/HR PRE-DEV Tc= 10.0 MIN 2 0.36 0.6 1.05 5 0.52 0.64 1.64 PRE-DEV C= 0.20 10 0.64 0.66 2.09 25 0.78 0.64 2.46 STORM A= 1.01 50 0.92 0.66 3.00 B= 0.67 100 1.01 0.67 3.35 STORM INTENSITY= 3.35 IN/HR PRE-DEV Qp= 1.17 CFS POST-DEVELOPMENT BASIN AREA PRE= 1.75 AC POST-DEVTc= 10.0 MIN POST-DEV C= 0.85 STORM INTENSITY= 3.35 IN/HR POST-DEV Qp= 4.99 CFS H:\1086\001\DOGS\Design\Storm\subarea A2-100.xls 1 OF 1 PRINTED: 4/29/2014 Existing East Ditch 1.5' depth Worksheet for Irregular Channel Project Description Project File h:\1086\001\dots\design\storm\flowmastr\eastswal.fm2 Worksheet Existing Swale 2+00 Flow Element Irregular Channel Method Manning's Formula Solve For Discharge Input Data Channel Slope 0.006000 ft/ft Water Surface Elevation 4,701.50 ft Elevation range: 4,700.00 ft to 4,705.54 ft. Station (ft) Elevation (ft) Start Station End Station Roughness -10.00 4,702.88 -10.00 20.00 0.035 -8.00 4,702.68 0.00 4,700.00 7.00 4,700.00 20.00 4,705.54 Results Wtd. Mannings Coefficient 0.035 Discharge 56.44 cfs Flow Area 16.50 ft2 Wetted Perimeter 15.55 ft Top Width 15.00 ft Height 1.50 ft Critical Depth 4,701.09 ft Critical Slope 0.019678 ft/ft Velocity 3.42 ft/s Velocity Head 0.18 ft Specific Energy 4,701.68 ft Froude Number 0.58 Flow is subcritical. 34/29/14 FlowMaster v5.17 31:46:10 PM Haestad Methods, Inc. 37 Brookside Road Waterbury,CT 06708 (203)755-1666 Page 1 of 1 Existing East Ditch 3' depth Worksheet for Irregular Channel Project Description Project File h:\1086\001\docs\design\storm\flowmastr\eastswal.fmi— Worksheet Existing Swale 2+00 Flow Element Irregular Channel Method Manning's Formula Solve For Discharge Input Data Channel Slope 0.006000 ft/ft Water Surface Elevation 4,703.00 ft Elevation range: 4,700.00 ft to 4,705.54 ft. Station (ft) Elevation (ft) Start Station End Station Roughness -10.00 4,702.88 -10.00 20.00 0.035 -8.00 4,702.68 0.00 4,700.00 7.00 4,700.00 20.00 4,705.54 Results Wtd. Mannings Coefficient 0.035 Discharge 219.96 cfs Flow Area 45.28 ftz Wetted Perimeter 25.22 ft Top Width 24.04 ft Height 3.00 ft Critical Depth 4,702.33 ft Critical Slope 0.016215 ft/ft Velocity 4.86 ft/s Velocity Head 0.37 ft Specific Energy 4,703.37 ft Froude Number 0.62 Flow is subcritical. Water elevation exceeds lowest end station by 0.12 ft. )4129/14 FlowMaster v5.17 )1:45:25 PM Haestad Methods, Inc. 37 Brookside Road Waterbury,CT 06708 (203)755-1666 Page 1 of 1 Culvert Calculator Report GRIFFIN-EXISTING-36"-CMP Solve For: Discharge Culvert Summary Allowable HW Elevation 4,702.68 ft Headwater Depth/Height 1.98 Computed Headwater Elevation 4,702.68 ft Discharge 54.25 cfs Inlet Control HW Elev 4,701.61 ft Tailwater Elevation 4,698.00 ft Outlet Control HW Elev 4,702.68 ft Control Type Outlet Control Grades Upstream Invert 4,696.74 ft Downstream Invert 4,696.00 ft Length 100.00 ft Constructed Slope 0.007400 ft/ft Hydraulic Profile Profile CompositeM2Pressure Depth,Downstream 2.39 ft Slope Type Mild Normal Depth N/A ft Flow Regime Subcritical Critical Depth 2.39 ft Velocity Downstream 8.98 ft/s Critical Slope 0.023758 ft/ft Section Section Shape Circular Mannings Coefficient 0.024 Section Material CMP Span 3.00 ft Section Size 36 inch Rise 3.00 ft Number Sections 1 Outlet Control Properties Outlet Control HW Elev 4,702.68 ft Upstream Velocity Head 0.92 ft Ke 0.90 Entrance Loss 0.82 ft Inlet Control Properties Inlet Control HW Elev 4,701.61 ft Flow Control N/A Inlet Type Projecting Area Full 7.1 ft2 K 0.03400 HDS 5 Chart 2 M 1.50000 HDS 5 Scale 3 C 0.05530 Equation Form 1 Y 0.54000 Project Engineer:wasia h:\...\docs\design\storm\culvertmstr\existing.cvm Academic Edition CulvertMaster v1.0 04/25/14 10:18:06 AM ©Haestad Methods,Inc. 37 Brookside Road Waterbury,CT 06708 USA (203)755-1666 Page 1 of 1 GEI#: 1086.001.040 DATE: 4/17/2014 ENGINEER: Chris Wasia I Detention Pond f �( S�( MODIFIED RATIONAL METHOD ` , NGINEERING, INC Qp=CiA J0.111 Il 114 Avr'. . R"llra Ili.M 1:ill 115 l n06 3.11 PRE-DEVELOPMENT RAINFALL FREQ= 10 YR(DURATION=1) i=A*(Tc/60)-B (CITY OF BOZEMAN) BASIN AREA PRE= 1.75 AC STORM EVENT STORM i COEFF INTENSITY YR A B IN/HR PRE-DEVTc= 10.0 MIN 2 0.36 0.6 1.05 5 0.52 0.64 1.64 PRE-DEV C= 0.20 10 0.64 0.66 2.09 25 0.78 0.64 2.46 STORM A= 0.64 50 0.92 0.66 3.00 B= 0.66 100 1.01 0.67 3.35 STORM INTENSITY= 2.09 IN/HR PRE-DEV Qp= 0.73 CFS POST-DEVELOPMENT POND VOLUME: CONST.RELEASE (CF) BASIN AREA PRE= 1.75 AC 1207.37 POST-DEV Tc= 10.0 MIN TRIANGLE RELEASE DETENTION (CF) POST-DEV C= 0.85 1905.65 STORM INTENSITY= 2.09 IN/HR AVERAGE VOLUME (CF) POST-DEV Qp= 3.11 CFS 1556.51 OUTLET STRUCTURE DESIGN RETENTION (CF) POND: Detention Pond 4391.10 REQUIRED VOL= 1S56.51 CF (AVG.B/W CONST.&TRIANGLE RELEASE) DIAMETER= 6.00 IN LENGTH OF PIPE= 20.00 FT QPRE= 0.73 CF5 HEAD WATER= 1.50 FT AREA= 0.13 SF N= 0.012 ORIFICE= 4 4/5 IN Ke= 0.50 ORIFICE FLOW= 0.74 CFS SLOPE OF PIPE= 0.005 FT/FT FLOW OUT= 0.98 CFS **NEED ORIFICE AVE SURF AREA= 804.91 SF H:\1086\001\DOCS\Design\Storm\Storm Pond.xls 1 OF 2 PRINTED: 4/24/2014 Detention Pond POND VOLUME CALC'S OUTLET STRUCUTRE CALC'S Triangle Release Constant Release SLOPE OF ENERGY ORIFICE DURATION INTENSITY Qp POND VOLUME POND VOLUME PIPE FLOW OUT (MIN) (IN/HR) (CFS) (CF) (CF) (FT/FT) (CFS) (CFS) 9.S0 2.16 3.21 1403.90 1076.10 0.000 0.936 0.741 10.50 2.02 3.01 1445.37 1102.4S 0.001 0.945 11.50 1.90 2.83 1482.97 1124.72 0.002 0.954 12.50 1.80 2.68 1517.24 1143.47 0.003 0.963 13.50 1.71 2.55 1548.62 1159.15 0.004 0.972 14.50 1,63 2.43 1577.45 1172.13 0.005 0,981 15.50 1.56 2.33 1604.02 1182.71 0.006 0.990 16.50 1.50 2.23 1628.57 1191.14 0.007 0.999 17.50 1.44 2.15 1651.29 1197.62 0.008 1.008 18.50 1.39 2.07 167236 120234 0.009 1.016 19.50 1.34 2.00 1691.93 1205.45 0.010 1.02S 20.50 1.30 1.93 1710.11 1207.09 0.011 1.033 21.50 1.26 1.87 1727.02 1207.37 0.012 1.042 22.50 1.22 1.82 1742.75 1206.39 0,013 1.050 23.50 1.19 1.77 1757.40 1204.24 0.014 1.058 24.50 1.16 1.72 1771.03 1201.00 0.015 1.067 25.50 1.13 1.67 1783.72 1196.75 0.016 1.075 26.50 1.10 1,63 1795.52 1191.55 0.017 1.083 27.50 1.07 1.59 1806.50 1185.45 0.018 1.091 28.50 1.05 1.56 1816.69 1178.52 0.019 1.099 29.50 1.02 1.52 1826.14 1170.79 0.020 1.107 30.50 1.00 1.49 1834.91 1162.32 0.021 1.115 31.50 0.98 1.46 1843.01 1153.13 0.022 1.123 32.50 0.96 1.43 1850.50 1143.27 0.023 1.130 33.50 0.94 1.40 1857.39 1132.78 0.024 1.138 34.50 0.92 1.37 1863.72 1121.67 0.025 1.146 35.50 0.90 1.35 1869.51 1109.99 0.026 1.153 36.50 0.89 1.32 1874.79 1097.75 0.027 1.161 37.50 0.87 1.30 1879.59 1084.99 0.028 1.168 38.50 0.86 1.28 1883.92 1071.72 0.029 1.176 39.50 0.84 1.25 1887.80 1057.96 0.030 1.183 40.50 0.83 1.23 1891.25 1043.74 0.031 1.191 41.50 0.82 1.21 1894.30 1029.07 0.032 1.198 42.50 0.80 1.20 1896.95 1013.98 0.033 1.205 43.50 0.79 1.18 1899.22 998.47 0.034 1.213 44.S0 0.78 1.16 1901.13 982.57 0.035 1.220 45.50 0.77 1.14 1902.69 966.29 0.036 1.227 46.50 0.76 1.13 190190 949.63 0.037 1.234 47.50 0.75 1.11 1904.80 932.62 0.038 1.241 48.50 0.74 1.10 1905.37 915.27 0,039 1.248 49.50 0.73 1.08 1905.65 897.58 0,040 1.255 H:\1086\001\DOCS\Design\Storm\Storm Pond.xls 2 OF 2 PRINTED: 4/24/2014 Valley Gutter @ Island Worksheet for Irregular Channel Project Description Project File h:\1086\001\docs\design\storm\flowmastr\valleygu.fm2 Worksheet valley gutter-curb Flow Element Irregular Channel Method Manning's Formula Solve For Discharge Input Data Channel Slope 0.005000 ft/ft Water Surface Elevation 0.79 ft Elevation range: 0.00 ft to 1.16 ft. Station (ft) Elevation (ft) Start Station End Station Roughness 0.00 1.16 0.00 23.50 0.015 20.00 0.06 23.50 39.60 0.030 21.50 0.00 23.00 0.06 23.50 0.56 39.60 0.79 Results Wtd. Mannings Coefficient 0.023 Discharge 18.01 cfs Flow Area 9.22 ft2 Wetted Perimeter 33.10 ft Top Width 32.87 ft Height 0.79 ft Critical Depth 0.68 ft Critical Slope 0.010178 ft/ft Velocity 1.95 ft/s Velocity Head 0.06 ft Specific Energy 0.85 ft Froude Number 0.65 Flow is subcritical. 04/25/14 Academic Edition FlowMaster v5.17 08:46:03 AM Haestad Methods, Inc. 37 Brookside Road Waterbury,CT 06708 (203)755-1666 Page 1 of 1 Culvert Calculator Report 15" A-2000 oolve For: Discharge Culvert Summary Allowable HW Elevation 1.75 ft Headwater Depth/Height 1.40 Computed Headwater Elevation 1.75 ft Discharge 5.94 cfs Inlet Control HW Elev 1.75 ft Tailwater Elevation 0.50 ft Outlet Control HW Elev 1.75 ft Control Type Entrance Control Grades Upstream Invert 0.00 ft Downstream Invert -3.50 ft Length 100.00 ft Constructed Slope 0.035000 ft/ft Hydraulic Profile Profile CompositePressureS1S2 Depth,Downstream 4.00 ft Slope Type N/A Normal Depth 0.53 ft Flow Regime N/A Critical Depth 0.99 ft Velocity Downstream 4.84 ft/s Critical Slope 0.005393 ft/ft Section Section Shape Circular Mannings Coefficient 0.010 Section Material PVC Span 1.25 ft Section Size 15 inch Rise 1.25 ft Number Sections 1 Dutlet Control Properties Outlet Control HW Elev 1.75 ft Upstream Velocity Head 0.51 ft Ke 0.50 Entrance Loss 0.25 ft Inlet Control Properties Inlet Control HW Elev 1.75 ft Flow Control Submerged Inlet Type Square edge w/headwall Area Full 1.2 ftz K 0.00980 HDS 5 Chart 1 M 2.00000 HDS 5 Scale 1 C 0.03980 Equation Form 1 Y 0.67000 Project Title:Great Northern Business Park Project Engineer:Genesis Engineering Inc. h:\...\docs\design\storm\culvertmstr\proposed.cvm Academic Edition CulvertMaster v1.0 04/24/14 05:02:06 PM ©Haestad Methods,Inc. 37 Brookside Road Waterbury,CT 06708 USA (203)755-1666 Page 1 of 1 Proposed Ditch Capacity Cross Section for Irregular Channel Project Description Project File h:\1086\001\docs\design\storm\flowmastr\post swa.fm2 Worksheet 1+75 Flow Element Irregular Channel Method Manning's Formula Solve For Discharge Section Data Wtd. Mannings Coefficient 0.041 Channel Slope 0.006500 ft/ft Water Surface Elevation 4,702.50 ft Discharge 96.99 cfs 4709.0 4708.0 4707.0 4706.0 4705.0 c 0 4704.0 m W 4703.0 4702.0 4701.0 4700.0 4699.0 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 Station (ft) D4/25/14 FlowMaster v5.17 11:34:41 AM Haestad Methods,Inc. 37 Brookside Road Waterbury,CT 06708 (203)755-1666 Page 1 of 1 ,-Q,6, ESIS Ft.Bu�inningGINEERING, INC of a Xcnv SIandard of Commitmen l Great Northern Business park Engineer: J. May 04/24/14 36" Round Outlet Structure - Pond 1 10 year pre 0.73 cfs 25 year post 3.65 cfs Using COB Weir Equation 10 yr flow through slot = CLHA(3/2) Q= 3.33*L*1.5(3/2) 0.73 cfs L=.119' 1.4280 in wide During storms greater than the 10 year, some additional flow will overtop the weir and flow through the outlet pipe. Remainder of flow up to 100 year storm will leave the pond through an overflow.