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HomeMy WebLinkAbout01 Headwaters Academy Flood Hazard Evaluation 2019_09_04 MEMO 32 Discovery Drive ♦ Bozeman, MT 59718 ♦ (406) 582-0221 ♦ Fax (406) 582-5770 To: City of Bozeman c/o Brian Heaston, PE From: Tom Chingas, EI and Jennifer Johnson, PE, CFM Project Name: Headwaters Academy, Flood Study Project Number: 19-024 Date: 07/15/2019 Re: Flood Hazard Evaluation for Mandeville Creek 45.686272°, -111.050167°, Bozeman, Montana Introduction The Headwaters Academy is currently undergoing site plan review with the City of Bozeman for potential development of their lot at 1005 Durston Road. The parcel borders Mandeville Creek on the west side; refer to Attachment 1 for a vicinity map. Because of the lot’s proximity to Mandeville Creek, Section 38.600.090.B.2 of the Bozeman Unified Development Code applies, and the following narrative describes modeling efforts to simulate the 100-year return interval flooding event for the existing conditions (the developer plans on utilizing the existing on-site buildings with minimal grading impacts). Hydrology Analysis Hydrologic information for the Mandeville Creek drainage basin was reviewed from the Bozeman Storm Water Facilities Plan (HDR Engineering, Inc. and Morrison-Maierle, Inc., May 2008) which applied the EPA SWMM Hydrology Method. The report delineates sub drainage areas in the city limits to a regional drainage network (Attachment 5 provides Figure 2.3-3 from the Storm Water Facilities Plan) and models runoff with various 24-hour storms. Basin EG5B from the Storm Water Facilities 12/9/2016 Allied Engineering Services, Inc. Flood Hazard Evaluation Page 2 Plan contributes to flow in Mandeville Creek at the project site and has an area of 2.1 square miles. For the downstream outlet of EG5B, the report’s authors calculated the existing 100-year, 24-hour peak flow to be 72.4 cfs. Allied performed a new hydrologic analysis for the project area’s drainage basin. The watershed was delineated using 2018 City of Bozeman (COB) LiDAR and the COB Infrastructure Viewer and has an area of 2.2 square miles (see Attachment 2). The hydrologic analysis applied a Type II, 24-hour, 100-year storm event with a total precipitation depth of 2.67 inches. The Bozeman Storm Water Facilities Plan also used a Type II storm for analysis. Hydrologic calculations were performed using both HEC-HMS and Hydraflow for comparison purposes. Within the models, excess rain was computed using the SCS Curve Number (CN) Method. To estimate CNs, the method’s only parameter, hydrologic soil properties were mapped using the USDA NRCS Web Soil Survey, and land use was estimated from aerial photography. A CN was then assigned to each combination of soil and land use properties. An SCS unit hydrograph was used to transform the excess rain. Resulting peak flows from HEC-HMS and Hydraflow were 186 cfs and 176 cfs respectively. StreamStats (a USGS web-based software) was also utilized to estimate the 100-yr peak flow of 162 cfs. StreamStats uses regression equations developed for western Montana. Ultimately, a peak flow of 186 cfs was conservatively used for the hydraulic analysis. Hydraulic Analysis The Army Corps of Engineer’s Hydrologic Engineering Center’s River Analysis System (HEC-RAS) version 5.0.7 (USACE, 2019) was used to model Mandeville Creek. A total of twelve cross-sections were modeled for the creek. Model setup is given in Attachment 2 and was completed using RASMapper. Elevation data for cross-sections was obtained from the 2018 COB LiDAR. Manning’s n values were obtained by referencing tables provided in “Open-Channel Hydraulics” (Chow, 1959). A Manning’s n value of 0.05-0.06 was appointed to the main channels describing a winding channel with some weeds and stones. A value of 0.05-0.07 was applied for the floodplains describing light brush and trees in the summer. A normal flow condition at the downstream end of the reach was applied as the boundary condition. A 0.00942 slope was used for the normal flow boundary condition and represents the average channel slope downstream of the model as measured from 2018 COB LiDAR . To ensure the downstream boundary condition was not affecting the model results near the project area, two model trials were run using a slope of 0.09 and 0.0009. The water surface for both trials converged with the existing conditions model at station 245, which is located approximately 330 feet downstream of the project area. Model outputs for the HEC-RAS analyses are included with the attachments. Modeled base flood elevations (BFEs) were mapped onto the 2018 COB LiDAR to determine inundation extents. Attachment 2 provides the flood inundation extents and BFEs. 12/9/2016 Allied Engineering Services, Inc. Flood Hazard Evaluation Page 3 Attachments: 1. Vicinity Map 2. Flood Inundation Map 3. Hydrology Calculations 4. HEC-RAS Model Results 5. Figure 2.3-3 from the Bozeman Storm Water Facilities Plan REFERENCES Bozeman, City of. (2019). Bozeman Municipal Code. Bozeman. Chow, V. T. (1959). Open-Channel Hydraulics. Caldwell: The Blackburn Press. FEMA. (2016). Bozeman Creek and Tributaries Floodplain Study. FEMA. HDR Engineering, Inc. and Morrison-Maierle, Inc. (May 2008). Bozeman Storm Water Facilities Plan. City of Bozeman. US Army Corps of Engineers. (2010). River Analysis System (HEC-RAS) V4.1.0. Davis, California. P:\2019\19-024 Headwaters Academy Site Plan\05 Design\H & H\Report\Headwaters Academy Flood Hazard Evaluation.docx 12/9/2016 Allied Engineering Services, Inc. Flood Hazard Evaluation Page 4 Attachment 1 Vicinity Map MANDEVILLECREEK PROJECTBOUNDARY ATTACHMENT: 1DRAWN BY: TWCDATE: 7/3/2019PROJECT: 19-024 REFERENCES:³0 1,500 3,000 4,500Feet HEADWATERS ACADEMY - FLOOD STUDYVICINITY MAPBOZEMAN, MT P :\2 0 1 9 \1 9 -0 2 4 H e a d w a t e r s A c a d e m y S i t e P l a n \0 7 C I M \A r c G I S \B a s e m a p _1 .m x d 1 inch = 3,000 feet 12/9/2016 Allied Engineering Services, Inc. Flood Hazard Evaluation Page 5 Attachment 2 Flood Inundation Map M A N D E V I L L E C R E E K 11TH D U R S T O N PROPERTY LINE EXISTINGAPPROACHCULVERT S T A 2 4 5 B F E = 4 7 7 4 .8 8 F T STA 1022BFE = 4786.79 FT S T A 2 1 1 B F E = 4 7 7 4 .2 4 F T S T A 8 0 3 B F E = 4 7 8 3 .8 5 F T S T A 7 2 8 B F E = 4 7 8 2 .5 2 F T S T A 3 3 7 B F E = 4 7 7 6 . 7 1 F T S T A 1 5 7 B F E = 4 7 7 3 .5 4 F T S T A 5 6 5 B F E = 4 7 8 0 .8 9 F T S T A 8 8 4 B F E = 4 7 8 5 .2 8 F T S T A 6 4 9 B F E = 4 7 8 1 .5 1 F T S T A 4 9 9 B F E = 4 7 7 9 .9 2 F TSTA 4 1 9 B F E = 4 7 7 8 .4 5 F T 4 7 8 6 4 7 8 54784 4 7 8 3 4 7 8 24781 4 7 8 0 4 7 7 84777 4 7 7 9 4776 4 7 8 9 4 7 8 8 4 7 8 9 4 7 8 7 4 7 7 4 4 7 7 2 4 7 7 14770 4 7 8 9 4 7 7 5 4787 4 7 8 8 4 7 7 3 4 7 8 7 4 7 8 7 4 7 8 4 4 7 8 4 4 7 7 64775 4 7 7 4 4784 Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GISUser Community ATTACHMENT: 2DRAWN BY: TWCDATE: 7/31/2019PROJECT: 19-024³0 40 80 120Feet H E A D W A T E R S A C A D E M Y - F L O O D S T U D YINUNDATION M A P F R O M 1 %-A N N U A L -C H A N C E E V E N TBOZEMAN, M T P :\2 0 1 9 \1 9 -0 2 4 H e a d w a t e r s A c a d e m y S i t e P l a n \0 7 C I M \A r c G I S \F l o o d _I n u n d a t i o n _M a p .m x d 1 inch = 80 feet AREA = 2.2SQUAREMILES CONTRIBUTINGWATERSHED PROJECT SITE Copyright:© 2013 National GeographicSociety, i-cubed Legend MODEL XS's Culvert WSE (100-Yr)High : 4786.79 Low : 4773.54 NOTES: 1. THE FEMA FLOOD INSURANCE RATE MAP PANEL 30031C0818D COVERS THE AREA OF INTEREST (ZONE D).2. THE 2018 BOZEMAN LIDAR SURFACE WAS USED FOR ELEVATION AND TERRAIN SURFACE DATA.3. ELEVATION DATUM FOR LIDAR SURFACE IS NAVD88. 4. FLOOD INUNDATION MAP DEVELOPED BY TOM CHINGAS, EI AND JENNIFER JOHNSON, PE, CFM. REFER TO REPORT FOR FLOOD STUDYDESCRIPTION.5. BFE = BASE FLOOD ELEVATION, ALSO CALLED 100-YEAR WATER SURFACE ELEVATION. ³ 0 1 20.5 Miles 12/9/2016 Allied Engineering Services, Inc. Flood Hazard Evaluation Page 6 Attachment 3 Hydrology Calculations Proj e c t : H e a d w a t e r s A c a d e m y F l o o d s t u S i m u l a t i o n R u n : R u n 1 Sub b a s i n : S u b b a s i n - 1 Star t o f R u n : 0 1 J a n 2 0 1 9 , 0 0 : 0 0 B a s i n M o d e l : B a s i n 1 End o f R u n : 0 2 J a n 2 0 1 9 , 0 0 : 0 0 M e t e o r o l o g i c M o d e l : M e t 1 Com p u t e T i m e : 0 3 J u l 2 0 1 9 , 1 5 : 5 6 : 4 2 C ontr o l S p e c i f i c a t i o n s : C o n t r o l 1 Volu m e U n i t s : IN Com p u t e d R e s u l t s Pea k D i s c h a r g e : 1 8 6 . 7 ( C F S ) D a t e / T i m e o f P e a k D i s c h a r g e : 01J a n 2 0 1 9 , 1 5 : 3 0 Prec i p i t a t i o n V o l u m e : 2.67 ( I N ) D i r e c t R u n o f f V o l u m e : 0 . 7 8 ( I N ) Los s V o l u m e : 1 . 7 9 ( I N ) B a s e f l o w V o l u m e : 0 . 0 0 ( I N ) Exce s s V o l u m e : 0 . 8 8 ( I N ) D i s c h a r g e V o l u m e : 0 . 7 8 ( I N ) Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v12 Wednesday, 07 / 3 / 2019 Hyd. No. 1 19-024 Hydrograph type = SCS Runoff Peak discharge = 176.27 cfs Storm frequency = 100 yrs Time to peak = 15.50 hrs Time interval = 15 min Hyd. volume = 4,609,781 cuft Drainage area = 1438.530 ac Curve number = 77.5 Basin Slope = 1.6 % Hydraulic length = 20896 ft Tc method = LAG Time of conc. (Tc) = 308.14 min Total precip. = 2.67 in Distribution = Type II Storm duration = 24 hrs Shape factor = 484 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 Q (cfs) 0.00 0.00 30.00 30.00 60.00 60.00 90.00 90.00 120.00 120.00 150.00 150.00 180.00 180.00 Q (cfs) Time (hrs) 19-024 Hyd. No. 1 -- 100 Year Hyd No. 1 12/9/2016 Allied Engineering Services, Inc. Flood Hazard Evaluation Page 7 Attachment 4 HEC-RAS Model Results 0 20 0 40 0 60 0 80 0 1000 47 7 0 47 7 2 47 7 4 47 7 6 47 7 8 47 8 0 47 8 2 47 8 4 47 8 6 47 8 8 Fl o o d _ H a z a r d _ E v a l P l a n : E x i s t i n g C o n d i t i o n s - D e t a i l e d S t ud y 7 / 2 5 / 2 0 1 9 Ma i n C h a n n e l D i s t a n c e ( f t ) E l e v a t i o n ( f t ) Legend EG 100-Yr WS 100-Yr Crit 100-Yr Ground LOB ROB 2 1 1 2 4 5 3 3 7 4 1 9 4 9 9 5 6 5 6 4 9 7 2 8 8 0 3 8 8 4 1 0 2 2 Ma n d e v i l l e C r e e k R e a c h 1 HE C - R A S P l a n : 1 0 0 - Y r R i v e r : M a n d e v i l l e C r e e k R e a c h : R e a c h 1 P r o f i l e : 1 0 0 - Y r Re a c h R i v e r S t a P r o f i l e E . G . E l e v W . S . E l e v V e l H e a d F r c t n L o s s C & E Lo s s Q L e f t Q C h a n n e l Q R i g h t T o p W i d t h (f t ) ( f t ) ( f t ) ( f t ) ( f t ) ( c f s ) ( c f s ) ( c f s ) ( f t ) Re a c h 1 1 0 2 2 1 0 0 - Y r 4 7 8 7 . 1 5 4 7 8 6 . 7 9 0 . 3 6 1 . 6 7 0 . 0 7 2 8 . 4 3 1 5 4 . 8 0 2 . 7 7 6 9.61 Re a c h 1 8 8 4 1 0 0 - Y r 4 7 8 5 . 4 1 4 7 8 5 . 2 8 0 . 1 3 1 . 3 0 0 . 0 1 4 0 . 1 4 1 3 4 . 8 7 1 0 . 9 9 135.70 Re a c h 1 8 0 3 1 0 0 - Y r 4 7 8 4 . 1 0 4 7 8 3 . 8 5 0 . 2 5 1 . 3 8 0 . 0 2 1 8 . 4 1 1 6 5 . 5 6 2 . 0 3 8 9.20 Re a c h 1 7 2 8 1 0 0 - Y r 4 7 8 2 . 7 0 4 7 8 2 . 5 2 0 . 1 8 1 . 0 5 0 . 0 2 5 2 . 9 3 1 1 6 . 1 1 1 6 . 9 6 88.97 Re a c h 1 6 4 9 1 0 0 - Y r 4 7 8 1 . 6 4 4 7 8 1 . 5 1 0 . 1 3 0 . 6 8 0 . 0 2 1 7 . 7 8 4 9 . 4 8 1 1 8 . 7 4 94.40 Re a c h 1 5 6 5 1 0 0 - Y r 4 7 8 0 . 9 3 4 7 8 0 . 8 9 0 . 0 5 0 . 7 5 0 . 0 2 5 7 . 7 8 2 6 . 2 3 1 0 1 . 9 9 115.54 Re a c h 1 4 9 9 1 0 0 - Y r 4 7 8 0 . 1 7 4 7 7 9 . 9 2 0 . 2 5 1 . 2 7 0 . 0 5 2 1 . 5 9 9 0 . 9 4 7 3 . 4 6 9 2.71 Re a c h 1 4 1 9 1 0 0 - Y r 4 7 7 8 . 5 4 4 7 7 8 . 4 5 0 . 0 9 1 . 5 4 0 . 0 2 5 2 . 3 4 8 9 . 7 9 4 3 . 8 8 9 9.92 Re a c h 1 3 3 7 1 0 0 - Y r 4 7 7 6 . 9 9 4 7 7 6 . 7 1 0 . 2 8 1 . 9 4 0 . 0 5 6 2 . 6 0 4 6 . 8 5 7 6 . 5 5 7 9.87 Re a c h 1 2 4 5 1 0 0 - Y r 4 7 7 5 . 0 1 4 7 7 4 . 8 8 0 . 1 3 0 . 4 7 0 . 0 2 3 2 . 0 8 5 5 . 3 1 9 8 . 6 1 7 4.66 Re a c h 1 2 1 1 1 0 0 - Y r 4 7 7 4 . 5 2 4 7 7 4 . 2 4 0 . 2 9 0 . 6 3 0 . 0 4 4 2 . 3 2 7 6 . 4 5 6 7 . 2 3 8 1.64 Re a c h 1 1 5 7 1 0 0 - Y r 4 7 7 3 . 6 9 4 7 7 3 . 5 4 0 . 1 5 6 3 . 9 2 7 1 . 0 4 5 1 . 0 4 1 1 0 . 9 5 0 20 40 60 80 10 0 12 0 140 47 8 3 47 8 4 47 8 5 47 8 6 47 8 7 47 8 8 47 8 9 Fl o o d _ H a z a r d _ E v a l P l a n : E x i s t i n g C o n d i t i o n s - D e t a i l e d S t ud y 7 / 2 5 / 2 0 1 9 Ri v e r = M a n d e v i l l e C r e e k R e a c h = R e a c h 1 R S = 1 0 2 2 St a t i o n ( f t ) E l e v a t i o n ( f t ) Legend EG 100-Yr WS 100-Yr Crit 100-Yr Ground Ineff Bank Sta .0 7 .0 6 .0 7 0 50 10 0 15 0 200 47 8 3 . 5 47 8 4 . 0 47 8 4 . 5 47 8 5 . 0 47 8 5 . 5 47 8 6 . 0 47 8 6 . 5 Fl o o d _ H a z a r d _ E v a l P l a n : E x i s t i n g C o n d i t i o n s - D e t a i l e d S t ud y 7 / 2 5 / 2 0 1 9 Riv e r = M a n d e v i l l e C r e e k R e a c h = R e a c h 1 R S = 8 8 4 St a t i o n ( f t ) E l e v a t i o n ( f t ) Legend EG 100-Yr WS 100-Yr Crit 100-Yr Ground Bank Sta .0 7 .0 6 .0 7 0 20 40 60 80 10 0 12 0 14 0 160 47 8 2 . 5 47 8 3 . 0 47 8 3 . 5 47 8 4 . 0 47 8 4 . 5 47 8 5 . 0 Fl o o d _ H a z a r d _ E v a l P l a n : E x i s t i n g C o n d i t i o n s - D e t a i l e d S t ud y 7 / 2 5 / 2 0 1 9 Riv e r = M a n d e v i l l e C r e e k R e a c h = R e a c h 1 R S = 8 0 3 St a t i o n ( f t ) E l e v a t i o n ( f t ) Legend EG 100-Yr WS 100-Yr Crit 100-Yr Ground Bank Sta .0 7 .0 6 .0 7 0 20 40 60 80 10 0 12 0 14 0 16 0 180 47 8 0 47 8 1 47 8 2 47 8 3 47 8 4 47 8 5 Fl o o d _ H a z a r d _ E v a l P l a n : E x i s t i n g C o n d i t i o n s - D e t a i l e d S t ud y 7 / 2 5 / 2 0 1 9 Riv e r = M a n d e v i l l e C r e e k R e a c h = R e a c h 1 R S = 7 2 8 St a t i o n ( f t ) E l e v a t i o n ( f t ) Legend EG 100-Yr WS 100-Yr Crit 100-Yr Ground Bank Sta .0 7 .0 6 .0 7 0 50 10 0 15 0 20 0 250 47 7 9 . 5 47 8 0 . 0 47 8 0 . 5 47 8 1 . 0 47 8 1 . 5 47 8 2 . 0 47 8 2 . 5 47 8 3 . 0 47 8 3 . 5 Fl o o d _ H a z a r d _ E v a l P l a n : E x i s t i n g C o n d i t i o n s - D e t a i l e d S t ud y 7 / 2 5 / 2 0 1 9 Riv e r = M a n d e v i l l e C r e e k R e a c h = R e a c h 1 R S = 6 4 9 St a t i o n ( f t ) E l e v a t i o n ( f t ) Legend EG 100-Yr WS 100-Yr Crit 100-Yr Ground Bank Sta .0 7 .0 6 .0 7 0 50 10 0 15 0 200 47 7 9 . 0 47 7 9 . 5 47 8 0 . 0 47 8 0 . 5 47 8 1 . 0 47 8 1 . 5 47 8 2 . 0 47 8 2 . 5 47 8 3 . 0 Fl o o d _ H a z a r d _ E v a l P l a n : E x i s t i n g C o n d i t i o n s - D e t a i l e d S t ud y 7 / 2 5 / 2 0 1 9 Riv e r = M a n d e v i l l e C r e e k R e a c h = R e a c h 1 R S = 5 6 5 St a t i o n ( f t ) E l e v a t i o n ( f t ) Legend EG 100-Yr WS 100-Yr Crit 100-Yr Ground Bank Sta .0 7 .0 6 .0 7 0 50 10 0 15 0 20 0 250 47 7 8 . 5 47 7 9 . 0 47 7 9 . 5 47 8 0 . 0 47 8 0 . 5 47 8 1 . 0 47 8 1 . 5 47 8 2 . 0 Fl o o d _ H a z a r d _ E v a l P l a n : E x i s t i n g C o n d i t i o n s - D e t a i l e d S t ud y 7 / 2 5 / 2 0 1 9 Riv e r = M a n d e v i l l e C r e e k R e a c h = R e a c h 1 R S = 4 9 9 St a t i o n ( f t ) E l e v a t i o n ( f t ) Legend EG 100-Yr WS 100-Yr Crit 100-Yr Ground Ineff Bank Sta .0 7 .0 6 .0 7 0 50 10 0 15 0 20 0 25 0 300 47 7 6 . 5 47 7 7 . 0 47 7 7 . 5 47 7 8 . 0 47 7 8 . 5 47 7 9 . 0 47 7 9 . 5 47 8 0 . 0 47 8 0 . 5 Fl o o d _ H a z a r d _ E v a l P l a n : E x i s t i n g C o n d i t i o n s - D e t a i l e d S t ud y 7 / 2 5 / 2 0 1 9 Riv e r = M a n d e v i l l e C r e e k R e a c h = R e a c h 1 R S = 4 1 9 St a t i o n ( f t ) E l e v a t i o n ( f t ) Legend EG 100-Yr WS 100-Yr Crit 100-Yr Ground Bank Sta .0 7 .0 6 .0 7 0 20 40 60 80 10 0 12 0 14 0 16 0 180 47 7 5 . 0 47 7 5 . 5 47 7 6 . 0 47 7 6 . 5 47 7 7 . 0 47 7 7 . 5 47 7 8 . 0 47 7 8 . 5 47 7 9 . 0 Fl o o d _ H a z a r d _ E v a l P l a n : E x i s t i n g C o n d i t i o n s - D e t a i l e d S t ud y 7 / 2 5 / 2 0 1 9 Riv e r = M a n d e v i l l e C r e e k R e a c h = R e a c h 1 R S = 3 3 7 St a t i o n ( f t ) E l e v a t i o n ( f t ) Legend EG 100-Yr WS 100-Yr Crit 100-Yr Ground Bank Sta .0 7 .0 6 .0 7 0 20 40 60 80 10 0 12 0 140 47 7 2 47 7 3 47 7 4 47 7 5 47 7 6 47 7 7 Fl o o d _ H a z a r d _ E v a l P l a n : E x i s t i n g C o n d i t i o n s - D e t a i l e d S t ud y 7 / 2 5 / 2 0 1 9 Riv e r = M a n d e v i l l e C r e e k R e a c h = R e a c h 1 R S = 2 4 5 St a t i o n ( f t ) E l e v a t i o n ( f t ) Legend EG 100-Yr WS 100-Yr Crit 100-Yr Ground Bank Sta .0 7 .0 6 .0 7 0 20 40 60 80 10 0 12 0 14 0 16 0 180 47 7 2 47 7 3 47 7 4 47 7 5 47 7 6 47 7 7 Fl o o d _ H a z a r d _ E v a l P l a n : E x i s t i n g C o n d i t i o n s - D e t a i l e d S t ud y 7 / 2 5 / 2 0 1 9 Riv e r = M a n d e v i l l e C r e e k R e a c h = R e a c h 1 R S = 2 1 1 St a t i o n ( f t ) E l e v a t i o n ( f t ) Legend EG 100-Yr WS 100-Yr Crit 100-Yr Ground Ineff Bank Sta .0 5 .0 5 .0 5 0 50 10 0 15 0 200 47 7 1 47 7 2 47 7 3 47 7 4 47 7 5 47 7 6 47 7 7 Fl o o d _ H a z a r d _ E v a l P l a n : E x i s t i n g C o n d i t i o n s - D e t a i l e d S t ud y 7 / 2 5 / 2 0 1 9 Riv e r = M a n d e v i l l e C r e e k R e a c h = R e a c h 1 R S = 1 5 7 St a t i o n ( f t ) E l e v a t i o n ( f t ) Legend EG 100-Yr WS 100-Yr Crit 100-Yr Ground Bank Sta .0 5 .0 5 .0 5 12/9/2016 Allied Engineering Services, Inc. Flood Hazard Evaluation Page 8 Attachment 5 Figure 2.3-3 (from the Bozeman Storm Water Facilities Plan) EG 6 A EG 1 D EG 7 C EG 7 H EG 7 B EG 7 G EG 2 D EG 5 Q EG 2 A EG 1 B EG T 1 A EG 5 B EG 7 F EG T 2 A BC 1 A EG 7 K EG 7 L EG 7 S BC 2 F EG 2 C EG 5 P BC 2 E BC 2 A EG 1 F EG 2 E EG 1 A EG 4 B EG 1 C EG 5 G EG 4 A BC 3 B BC 3 A BC 2 B BC 2 C EG 3 A EG 1 G EG 4 C EG 6 B EG 1 E EG 2 B EG 5 E EG T 1 B FIGURE 2.3-3 City of Bozeman Regional Drainage NetworkPrayBozeman Be l g r a d e Ma n h a t t a n Livingston Ga l l a t i n G a t e w a y Legend Catchments Bozeman Creek East Gallatin River Streamlines City Limits Regional Drainage Basins Bozeman Creek Basin East Gallatin River BasinPark Co. G a l l a t i n C o . M a d i s o n C o . E a s t G a l l a t in R i v e r Bozeman C r e e k Bozeman Area Watershed 01 2 3 4 0. 5 Mi l e s ²