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Model Cross-Section Area Removed from SFHA Proposed 0.2% Annual Chance Floodplain Proposed 1% Annual Chance Floodplain Proposed Floodway Plot Stamp: 2/24/2020 4:59:32 PM - Daniel Child File: W:\21914760\Storm\LOMR Submittal\Exhibits\AutoCAD\1476-LOMR-WORKMAP.dwg, Tab: MAP

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- 0.2% ANNUAL CHANCE FLOODPLAIN - 1% ANNUAL CHANCE FLOODPLAIN - FLOODWAY - 0.2% ANNUAL CHANCE FLOODPLAIN - 1% ANNUAL CHANCE FLOODPLAIN - REGULATORY FLOODWAY - MODEL CROSS-SECTION - EFFECTIVE CROSS-SECTION - BUILDING FACE - MINOR CONTOURS - MAJOR CONTOURS - RIGHT-OF-WAY LINE - PROPERTY LINE 168

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C N TEL: (503) 419 - 2500 FAX: (503) 419 - 2600 www.cardno.com A L CITY OF FAIRVIEW FAIRVIEW, OREGON MODEL CROSS-SECTION DATA TABLES *ELEVATION TAKEN FROM LIDAR DIGITAL TERRAIN MODEL

SECTION POINT # NORTHING EASTING ELEVATION #6 6679 177504.16 409152.73 152.79 #11 7023 177233.10 409341.72 157.02 #15 7170 177081.15 409043.07 161.08 #22 7257 176603.24 408672.25 164.07 #01 6226 177940.52 409138.53 141.60 STA 7630 6435 177503.97 409168.54 152.47 STA 8044 7031 177222.04 409364.12 156.85 STA 8479 7169 177065.35 409048.24 159.96 STA 9145 7258 176602.49 408678.95 163.64 STA 7606 6057 177939.27 409153.87 140.83 6436 177504.26 409170.42 152.14 7033 177204.93 409372.61 156.63 7168 177056.85 409050.15 158.85 7259 176602.77 408686.38 159.43 6100 177939.63 409162.97 140.33 6438 177506.39 409176.37 151.10 7056 177187.98 409374.23 149.17 7129 177040.30 409057.87 150.89 7260 176601.20 408688.90 159.35 6987 177942.55 409170.70 138.76 6439 177507.59 409185.23 150.69 7057 177185.34 409375.64 147.65 7128 177038.02 409058.89 148.99 7261 176601.24 408690.63 157.88 6986 177941.62 409172.36 135.45 666 177536.55 409256.88 147.36 7058 177181.82 409377.71 147.47 7127 177031.75 409057.80 149.48 7262 176601.41 408692.71 157.93 6985 177939.40 409199.62 131.41 665 177539.84 409260.64 147.56 7059 177176.59 409379.33 147.48 7126 177027.09 409058.97 149.48 7263 176601.89 408695.19 157.93 6984 177939.32 409206.91 130.92 664 177541.82 409262.92 145.25 7060 177172.18 409381.00 149.77 7125 177024.26 409059.74 150.85 7264 176601.75 408697.62 159.25 6983 177935.24 409211.72 131.17 663 177552.54 409267.02 145.72 7061 177146.19 409393.57 151.34 6931 177007.17 409065.28 158.66 7265 176604.30 408712.30 160.32 6982 177933.76 409217.83 134.99 662 177554.39 409268.41 147.86 7106 177118.32 409401.23 152.34 6928 177004.33 409066.22 159.35 7266 176605.43 408733.46 160.00 TEL: (503) 419 - 2500 FAX: (503) 419 - 2600 www.cardno.com 6720 SW MACADAM AVE, STE 150, PORTLAND, OR 97219 6981 177929.49 409229.23 137.21 661 177559.49 409273.86 148.22 7107 177109.84 409405.67 152.40 6929 176996.63 409068.37 159.16 7267 176612.47 408768.46 159.99 PORTLAND #2 *200 177864.51 409135.70 142.97 *600 177573.06 409295.90 148.56 7108 177102.21 409411.93 156.14 6930 176996.00 409068.54 158.73 *2300 176621.93 408840.29 161.51 STA 7287 617 177863.97 409164.97 143.08 *601 177600.55 409319.96 149.09 7081 177098.59 409411.63 156.32 #16 *1600 176994.91 408843.58 159.67 *2301 176624.08 408856.89 161.97 618 177863.45 409170.57 143.13 *602 177597.44 409424.64 149.83 7080 177084.94 409415.38 156.29 STA 8666 *1601 176987.53 408853.05 159.27 #23 7281 176498.48 408674.14 165.12 619 177863.33 409171.31 136.72 *603 177597.23 409493.00 150.94 7109 177081.61 409422.63 156.21 *1602 176970.54 408874.86 156.47 STA 9246 7280 176499.20 408684.55 164.71 623 177863.36 409177.57 136.64 #7 6989 177434.12 409269.26 153.10 6975 177079.35 409424.60 156.15 *1603 176959.27 408889.36 152.07 7279 176499.92 408690.55 160.94 624 177863.07 409184.99 136.98 STA 7715 6988 177445.58 409280.20 152.73 6976 177073.42 409425.63 156.13 *1604 176957.26 408891.94 151.73 7278 176501.18 408701.93 159.57 625 177862.68 409185.82 143.10 6990 177462.63 409294.28 148.62 6977 177072.76 409425.77 155.69 *1605 176955.44 408894.30 151.99 7277 176500.83 408704.40 158.63 626 177862.68 409196.28 143.33 6991 177470.24 409302.73 147.86 *1100 177045.60 409430.47 155.86 *1606 176944.56 408908.32 156.71 7276 176501.00 408706.18 158.46 #3 *300 177835.01 409134.72 143.74 6992 177471.82 409305.89 145.59 #12 7036 177194.94 409290.42 157.06 *1607 176940.76 408913.23 157.45 7275 176500.93 408709.03 158.51 STA 7317 637 177834.22 409164.58 143.59 6993 177475.54 409310.01 144.72 STA 8184 7037 177188.75 409290.22 156.67 *1608 176927.61 408921.41 158.02 7274 176501.28 408710.39 159.76 633 177833.39 409169.95 143.16 6994 177481.02 409314.12 145.56 7049 177176.28 409291.40 149.58 #17 7246 176805.96 408820.05 159.74 7273 176500.24 408718.99 161.96 6206 177833.22 409170.41 143.01 6995 177482.19 409315.76 147.31 7048 177173.29 409291.47 147.50 STA 8843 7245 176799.75 408823.57 159.46 7272 176501.97 408730.64 163.30 632 177833.31 409170.65 137.47 6996 177493.05 409327.85 147.99 7047 177169.34 409292.45 147.19 7244 176789.79 408828.03 154.93 7271 176501.32 408736.34 160.45 631 177833.16 409176.12 136.85 *700 177549.37 409397.70 149.95 7045 177163.02 409293.03 149.65 7243 176788.97 408841.95 153.61 7270 176502.17 408740.30 160.36 630 177832.97 409180.90 137.59 *701 177570.75 409452.75 150.39 7115 177153.45 409294.49 150.09 7242 176788.85 408843.25 152.91 7269 176503.32 408745.15 162.37 629 177832.99 409184.26 139.75 *702 177570.62 409492.92 150.89 7116 177132.60 409296.61 155.06 7241 176789.58 408846.96 152.73 7268 176502.10 408768.14 163.73 628 177832.76 409185.00 143.16 #8 6997 177400.97 409299.56 153.63 7117 177128.24 409297.00 156.51 7240 176788.99 408850.03 152.67 #24 7220 176668.50 408806.05 160.09 627 177832.88 409195.00 143.85 STA 7788 6998 177406.49 409321.97 152.99 7118 177113.59 409301.18 157.85 7239 176789.11 408851.18 153.68 STA 9007 7219 176658.14 408805.42 158.98 #4 *400 177619.79 409044.65 149.90 6999 177408.72 409339.15 149.02 7119 177085.50 409306.79 157.60 7238 176788.92 408859.69 157.96 7218 176655.16 408804.52 156.22 STA 7520 *401 177630.72 409070.62 149.90 7000 177409.49 409342.18 146.28 6964 177058.93 409320.45 157.19 7237 176789.23 408866.01 158.69 7217 176650.35 408804.93 155.94 6337 177632.49 409113.32 149.50 7001 177410.99 409344.79 145.99 6967 177053.04 409321.52 157.13 7236 176790.73 408888.12 158.74 7216 176647.85 408804.34 156.05 6338 177633.49 409118.38 148.80 7002 177411.88 409348.20 146.03 6968 177052.40 409321.65 156.76 #18 10289 176793.78 408793.30 159.79 7215 176645.55 408804.69 158.09 6339 177633.46 409127.95 149.24 7003 177413.02 409350.54 147.81 #13 7301 177120.59 409191.62 158.87 STA 31 10287 176788.72 408795.65 159.57 7214 176638.94 408804.73 160.92 6320 177635.00 409143.07 149.39 7004 177436.82 409376.67 150.05 STA 8324 6618 177116.89 409191.91 158.53 10286 176788.59 408795.81 160.03 7212 176636.26 408804.52 161.41 6356 177552.51 409134.63 150.85 *800 177457.37 409401.12 150.43 7144 177112.32 409190.60 158.54 10288 176783.14 408799.24 160.12 7213 176626.17 408804.44 161.50 638 177632.05 409178.23 148.95 *801 177521.30 409459.38 150.31 6628 177101.45 409189.94 158.33 30130 176781.89 408800.78 159.82 #25 7228 176726.97 408822.54 159.96 646 177631.85 409189.55 144.82 *802 177553.22 409492.86 150.84 7143 177099.56 409193.33 157.78 30129 176776.51 408803.54 156.14 STA 8904 7227 176728.47 408838.93 159.54

645 177631.64 409195.71 144.64 #9 7013 177339.57 409328.78 154.60 7142 177096.53 409194.67 155.28 30057 176768.04 408804.51 156.08 7226 176728.99 408844.08 155.44 SURVEYED CREEK CROSS SECTIONS FAIRVIEW CREEK LOMR CITY OF FAIRVIEW FAIRVIEW, OREGON 644 177631.18 409203.61 145.25 STA 7859 7012 177341.72 409343.74 153.92 7141 177086.45 409203.09 149.94 30054 176761.98 408806.86 159.43 7225 176729.07 408846.32 154.45 BY 642 177630.80 409204.79 149.47 7011 177347.03 409363.91 149.28 7140 177082.85 409205.70 147.86 #19 7205 176764.31 408742.75 160.72 7224 176728.84 408849.75 153.89 643 177629.86 409213.08 149.12 7010 177351.91 409378.60 148.40 7139 177077.64 409205.10 147.52 STA 82 7206 176758.00 408748.65 160.82 7223 176729.04 408851.91 154.62 *402 177639.55 409278.14 148.58 7009 177352.61 409382.41 146.23 7138 177073.05 409208.54 147.85 7207 176753.40 408753.94 157.45 7222 176728.67 408857.87 158.97 *403 177639.44 409315.54 148.49 7008 177353.74 409386.70 145.87 7137 177071.64 409209.51 150.19 7208 176749.47 408757.97 156.86 7221 176727.63 408874.30 159.67 *404 177636.23 409422.59 149.91 7007 177354.61 409389.05 145.66 7136 177068.57 409212.44 150.79 7209 176747.64 408758.82 157.52 #26 7229 176770.70 408826.79 159.70 *405 177636.01 409493.12 149.78 7006 177356.39 409390.54 148.61 7152 177052.28 409214.01 157.95 7210 176742.80 408763.57 160.25 STA 8861 7230 176771.56 408833.93 158.30 #5 *500 177594.94 409055.22 150.42 7005 177362.71 409416.46 150.59 6884 177047.43 409214.37 158.21 7211 176735.75 408772.70 159.79 7231 176772.31 408839.76 154.43 STA 7537 *501 177606.22 409080.63 149.72 7068 177364.20 409422.28 150.78 6881 177038.59 409216.46 158.28 #20 7249 176715.32 408717.48 161.08 7232 176771.54 408844.67 153.95 6346 177607.75 409114.46 150.01 *900 177372.78 409464.43 151.79 6882 177032.69 409217.70 158.18 STA 123 7250 176713.96 408727.43 160.11 7233 176771.55 408849.23 154.36

6344 177608.25 409120.94 149.47 *901 177406.92 409640.37 150.17 6883 177032.05 409217.75 157.87 7251 176714.09 408727.54 160.10 7234 176771.36 408858.21 159.25 DESCRIPTION 6321 177611.36 409145.03 149.95 *902 177450.39 409666.37 151.46 #14 6847 177099.58 409092.48 157.89 7252 176713.60 408735.03 157.52 7235 176771.10 408876.14 159.55 6279 177612.04 409160.90 149.51 *903 177463.15 409669.36 151.57 STA 8429 7175 177083.88 409091.53 157.83 7253 176712.66 408739.94 157.39 DATE 649 177614.47 409184.85 149.74 #10 7014 177270.11 409333.07 156.78 7174 177077.91 409090.50 159.30 7254 176711.39 408745.78 157.37

648 177615.66 409196.01 149.60 STA 7946 7015 177269.59 409357.81 156.04 7173 177076.06 409090.54 159.20 7255 176710.99 408753.41 159.94 # 647 177616.01 409197.49 145.43 7016 177269.19 409367.47 150.80 7172 177067.64 409092.09 156.80 7256 176707.69 408766.54 159.87

X-SEC 656 177615.36 409201.19 144.61 7017 177268.15 409375.58 149.63 7134 177053.49 409100.19 150.25 #21 10356 176695.00 408700.06 161.82

, Tab: 655 177614.77 409211.36 144.84 7018 177267.69 409377.02 148.41 7133 177051.12 409102.35 148.11 STA 186 30084 176690.05 408722.24 160.76 RED PROFES TE SIO IS GINEE N 653 177614.69 409212.99 149.89 7019 177266.83 409388.64 147.69 7132 177048.80 409104.41 148.30 30167 176687.29 408731.50 158.00 G EN R A E L R 654 177613.93 409220.79 149.58 7020 177266.57 409394.80 147.92 7131 177042.77 409104.70 149.17 30168 176685.19 408738.09 157.97 60175PE FOR *502 177615.60 409333.13 149.25 7021 177265.83 409396.36 149.37 7130 177041.19 409106.06 150.55 30161 176682.90 408745.88 158.32 OREGON J 3 *503 177615.47 409378.16 149.61 7022 177262.24 409422.92 150.97 6933 177021.40 409113.67 158.53 30156 176680.99 408752.12 160.32 UREVIEWL 0 . 15 ONLY, 2 0 C E I C *504 177615.34 409423.18 150.25 7069 177268.61 409439.70 151.45 6908 177019.44 409116.68 158.96 20357 176669.65 408774.79 161.13 DOMI R J E S *505 177615.12 409493.06 150.65 *1000 177277.98 409484.34 152.04 6920 177013.31 409121.02 158.69 *2200 176669.46 408784.90 160.45 RENEWS: 08/09/21 *1001 177310.62 409637.88 151.36 DATE 02/24/2020 *1002 177315.96 409676.96 151.43 DRAWN KNY *1003 177322.61 409707.98 152.32 DESIGNED DEC

Daniel Child CHECKED CJ - PROJECT # 21914760

SHEET TITLE SURVEY X-SECTIONS SHEET NUMBER 2/24/2020 4:59:33 PM 2/24/2020

W:\21914760\Storm\LOMR Submittal\Exhibits\AutoCAD\1476-LOMR-WORKMAP.dwg W:\21914760\Storm\LOMR 02

DRAFT LAND USE # #### File: Plot Stamp: Plot Stamp:

Hydrology Report Fairview Creek Bypass – Letter of Map Revision

March 2020

Prepared For City of Fairview, Oregon

March 2020

Hydrology Report Fairview Creek Bypass – Letter of Map Revision

Contact Information Document Information Cardno 6720 SW Macadam Ave, Suite #200 Portland, Oregon 97219 Telephone: 503.419.2500 Facsimile: 503.419.2600 [email protected] www.cardno.com

Prepared for City of Fairview, Oregon Project Name Hydrology Report Fairview Creek Bypass – Letter of Map Revision

File Reference 1476-Hydrology Report.docx Job Reference 21914760 Date March 2020

Document History

Version Effective Date Description of Revision Prepared by Reviewed by 1.0 09/04/2019 Initial Draft Daniel Child Cedomir Jesic 1.1 01/09/2020 First Review Daniel Child Cedomir Jesic 1.2 03/26/2020 Final Draft Daniel Child Cedomir Jesic

© Cardno. Copyright in the whole and every part of this document belongs to Cardno and may not be used, sold, transferred, copied or reproduced in whole or in part in any manner or form or in or on any media to any person other than by agreement with Cardno. This document is produced by Cardno solely for the benefit and use by the client in accordance with the terms of the engagement. Cardno does not and shall not assume any responsibility or liability whatsoever to any third party arising out of any use or reliance by any third party on the content of this document.

March 2020 Cardno Document Information i 1476-Hydrology Report.docx Hydrology Report Fairview Creek Bypass – Letter of Map Revision

Table of Contents 1 Introduction ...... 1-1 1.1 Study Area ...... 1-1 1.2 Purpose of Study ...... 1-3 1.3 Type of Flooding ...... 1-3 1.4 Flooding History ...... 1-3 2 Study Area Characteristics ...... 2-3 2.1 Watershed Size ...... 2-3 2.2 Soils and Topography ...... 2-3 2.3 Rainfall and Climate ...... 2-7 2.4 Land Use ...... 2-7 2.5 Sub-Basins ...... 2-7 3 Approach & Methodology ...... 3-10 3.1 Methodology ...... 3-10 3.1.1 Rainfall ...... 3-10 3.1.2 Rainfall Losses ...... 3-12 3.1.3 Sub-Basin Response ...... 3-16 3.1.4 Routing ...... 3-17 3.1.5 Channel Storage ...... 3-17 3.1.6 Reservoir Storage ...... 3-17 3.1.7 Calibration Approach...... 3-18 3.2 Assumptions ...... 3-20 3.3 Gages ...... 3-21 3.4 Urbanization ...... 3-23 4 Discharge Comparison ...... 4-23 5 Discharge Summary ...... 5-23 6 References ...... 6-24

Appendices Appendix A Data Files

March 2020 Cardno Table of Contents ii 1476-Hydrology Report.docx Hydrology Report Fairview Creek Bypass – Letter of Map Revision

Tables Table 2-1 Fairview Creek Watershed Soils ...... 2-5 Table 2-2 Fairview Creek Watershed Zoning ...... 2-7 Table 3-1 Design Storm Events ...... 3-12 Table 3-2 Vegetative Cover CN Values ...... 3-13 Table 3-3 Impervious Percentage By Land Use Cover ...... 3-13 Table 3-4 Impervious Percentage by Special Case ...... 3-14 Table 3-5 Depression Storage Parameters ...... 3-16 Table 3-6 Reservoir Storage Summary ...... 3-17 Table 3-7 Sensitivity Analysis Summary ...... 3-18 Table 3-8 Fairview Creek Gage Measurement ...... 3-21 Table 4-1 100-year Discharge Comparison ...... 4-23 Table 5-1 Summary of Discharges ...... 5-23

Figures Fairview Creek Watershed ...... 1-2 Fairview Creek Watershed Soils ...... 2-4 Fairview Creek Topography ...... 2-6 Fairview Creek Sub-Basin Map ...... 2-8 Sub-Basin Sample ...... 2-9 KTTD Rain Gage December 2015 ...... 3-11 KTTD Rain Gage February 2018 ...... 3-11 25-year Type 1A Hydrograph ...... 3-12 Impervious Cover ...... 3-15 NE Glisan Street Gage Calibration Results ...... 3-19 NE Sandy Blvd Gage Calibration Results ...... 3-20 I-84 Gage Calibration Results ...... 3-20 Gage Location Map ...... 3-22

March 2020 Cardno Table of Contents iii 1476-Hydrology Report.docx Hydrology Report Fairview Creek Bypass – Letter of Map Revision

Acronyms 1D One Dimensional CN NRCS Curve Number DEM Digital Elevation Model DOGAMI Oregon Department of Geology & Mineral Industries EPA United States Environmental Protection Agency FEMA Federal Emergency Management Agency FIS Flood Insurance Study GIS Geographic Information System HU Hydrologic Unit LiDAR Light Detection and Ranging NFIP National Flood Insurance Program NRCS USDA Natural Resource Conservation Service SWMM Storm Water Management Model TBD To Be Determined USDA United States Department of Agriculture USGS United States Geological Survey

March 2020 Cardno Table of Contents iv 1476-Hydrology Report.docx Hydrology Report Fairview Creek Bypass – Letter of Map Revision

1 Introduction

1.1 Study Area The Fairview Creek Watershed is in Multnomah County, Oregon and is contained within USGS Hydrologic Unit (HU) 170900120201 (Columbia Slough). Interstate 84 runs perpendicular to the creek through the northern half of the watershed, with the creek running through the cities of Gresham and Fairview. The watershed terminates at Fairview Lake which is controlled by weir gates and discharges to the Columbia Slough. Water levels in the Slough and the lake are mechanically regulated by Multnomah County Drainage District. This hydrologic analysis was originally performed as part of the Fairview Creek Stormwater Master Plan Addendum prepared for the City of Fairview in April 2019 by Cardno. The extent of this study is limited to the reach of Fairview Creek that lies within the boundaries of the City of Fairview and starts downstream of NE Glisan Street and ends at Fairview Lake. Figure 1-1 illustrates the watershed boundary of Fairview Creek, and the extent of the hydrologic study.

March 2020 Cardno Introduction 1-1 1476-Hydrology Report.docx Hydrology Report Fairview Creek Bypass – Letter of Map Revision

Fairview Creek Watershed

March 2020 Cardno Introduction 1-2 1476-Hydrology Report.docx Hydrology Report Fairview Creek Bypass – Letter of Map Revision

1.2 Purpose of Study The purpose of this study is to provide greater accuracy in flood prediction for the study area by taking advantage of improved hydrologic analysis methodology, and utilizing the availability of better information including gage data and storm sewer mapping. At the time of drafting, this study is intended to only support the hydraulic analysis conducted in the proposed remapping of the Fairview Creek floodplain in the vicinity of the intersection of NE Halsey Street and NE 223rd Avenue. However, the study area for this hydrologic analysis is expanded across the City of Fairview in order to allow for better hydrologic data for use in future mapping efforts.

1.3 Type of Flooding The entire study area is riverine without any tidal influences. The downstream boundary of the watershed at Fairview Lake is roughly 73 miles east of the Pacific Ocean and roughly 90 miles southeast of the mouth of the Columbia River.

1.4 Flooding History Fairview Creek has recent history with flooding. During December 2015, the gage at NE Glisan Street registered a roughly 25-year flow and flooding was reported in the parking lot of the property at 22455 NE Halsey Street, located northeast of the NE Halsey Street and NE 223rd Avenue intersection.

2 Study Area Characteristics

2.1 Watershed Size At the downstream boundary of the Fairview Creek Watershed at Fairview Lake, the watershed encompasses approximately 5.9 square miles and included portions of the City of Gresham, City of Wood Village, and the City of Fairview.

2.2 Soils and Topography The Fairview Creek Watershed is composed of predominantly hydrologic group ‘B’ and ‘C’ type soils with a mix of hydrologic group ‘D’ soils in undrained areas. Figure 2-1 illustrates the coverage of soil types across the watershed, and Table 2-1 quantifies the soils present in the watershed and their respective percentage of cover. The watershed slopes downward from the south to the north, with a maximum elevation of 604.4 feet (NAVD 88), a minimum elevation of 13.5 (NAVD 88), an average channel slope of 0.8%, and an average basin slope of 7%. Figure 2-2 shows the elevation contours across the watershed at 10 foot intervals.

March 2020 Cardno Study Area Characteristics 2-3 1476-Hydrology Report.docx Hydrology Report Fairview Creek Bypass – Letter of Map Revision

Fairview Creek Watershed Soils

March 2020 Cardno Study Area Characteristics 2-4 1476-Hydrology Report.docx Hydrology Report Fairview Creek Bypass – Letter of Map Revision

Table 2-1 Fairview Creek Watershed Soils Percent of USGS Map Hydrologic Coverage USGS Map Unit Name Total Unit Symbol Soil Group Area (ac) Coverage 1A Aloha silt loam, 0 to 3 percent slopes C/D 155.6 4.1% 1B Aloha silt loam, 3 to 8 percent slopes C/D 19.2 0.5% 2A Aloha-Urban land complex, 0 to 3 percent slopes C/D 257.7 6.8% 25A Latourell loam, 0 to 3 percent slopes B 325.9 8.6% 25B Latourell loam, 3 to 8 percent slopes B 317.9 8.4% 25C Latourell loam, 8 to 15 percent slopes B 91.2 2.4% 25D Latourell loam, 15 to 30 percent slopes B 42.7 1.1% 26A Latourell-Urban land complex, 0 to 3 percent slopes B 189.6 5.0% 26B Latourell-Urban land complex, 3 to 8 percent slopes B 141.8 3.8% 29A Multnomah silt loam, 0 to 3 percent slopes B 371.8 9.8% 29B Multnomah silt loam, 3 to 8 percent slopes B 167.7 4.4% 29C Multnomah silt loam, 8 to 15 percent slopes B 86.3 2.3% 29D Multnomah silt loam, 15 to 30 percent slopes B 71.7 1.9% 29E Multnomah silt loam, 30 to 60 percent slopes B 31.0 0.8% 30A Multnomah-Urban land complex, 0 to 3 percent slopes B 510.9 13.5% 30B Multnomah-Urban land complex, 3 to 8 percent slopes B 145.0 3.8% 36A Quafeno loam, 0 to 3 percent slopes C 91.5 2.4% 36B Quafeno loam, 3 to 8 percent slopes C 58.2 1.5% 36C Quafeno loam, 8 to 15 percent slopes C 27.8 0.7% 37B Quatama loam, 3 to 8 percent slopes C 23.7 0.6% 37C Quatama loam, 8 to 15 percent slopes C 16.3 0.4% 40 Rafton silt loam, protected B/D 19.5 0.5% 45 Sauvie silt loam, protected C 19.6 0.5% 51C Urban land-Latourell complex, 8 to 15 percent slopes B 3.8 0.1% 52C Urban land-Multnomah complex, 8 to 15 percent slopes 16.9 0.4% 54B Urban land-Quatama complex, 3 to 8 percent slopes 44.8 1.2% 55 Wapato silt loam C/D 75.6 2.0% 57 Wollent silt loam C/D 367.8 9.7% PT Pits 40.6 1.1% W Water 43.7 1.2% Total 3775.9 100.0% For the purposes of analysis, map units with no reported hydrologic soil group were assumed to be of hydrologic soil group ‘D’ with the exception of the Water map unit which is considered to instead be impervious area.

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Fairview Creek Topography

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2.3 Rainfall and Climate The City of Fairview sees a typical annual precipitation of 44.9 inches based on data from for Troutdale, Oregon with a period of record of July 1965 to April 2016. This data has been processed and summarized by the Desert Research Institute’s Western Regional Climate Center (https://wrcc.dri.edu/).

2.4 Land Use Based on zoning available for the Portland Metro Area, the Fairview Creek watershed is roughly 2% commercial, 22% industrial, 58% residential, 15% streets and public right-of-way, and 3% open space. Table 2-2 outlines the specific zoning coverage for the watershed. Table 2-2 Fairview Creek Watershed Zoning

Coverage Percent Zoning Class Area (sq mi) Coverage

Central Commercial 0.07 1.1% Neighborhood Commercial 0.04 0.6% Future Urban Development 0.01 0.2% Industrial Campus 0.06 1.1% Heavy Indistrial 1.19 20.1% Light Industrial 0.04 0.6% Multi-Family Residential 0.80 13.5% Mixed-Use Residential 1.07 18.1% Parks/Open Space 0.21 3.6% Single-Family Residential 1.57 26.6% Streets/Right-of-Way 0.86 14.5% Total 5.90 100%

2.5 Sub-Basins Sub-basins were divided with the primary goal of evaluating the City of Fairview’s storm sewer and stormwater drainage system for Fairview Creek. These sub-basins were delineated for each point of connection to the City’s storm sewer system and for key discharge locations to Fairview Creek. Sub-basins were delineated by hand using topographic data from a digital elevation model (DEM) developed from high- resolution light detection and ranging (LiDAR) collected and compiled in 2014 by the Oregon Department of Geology & Mineral Industries (DOGAMI) for the Portland Metro area. Specifically, the data for the USGS 7.5 minute quadrangle 45122E4 was used for this study. Sub-basins for the Fairview Creek watershed upstream of NE Glisan Street and outside the immediate study area were delineated based on the same topographic data but were not sub-divided to the same detail as within the study area. Figure 2-3 outlines the Fairview Creek Watershed, illustrating the coverage of the study area and sub-basin extent. Figure 2-4 provides a representative sample of the sub-basin coverage within the study area.

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Fairview Creek Sub-Basin Map

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Sub-Basin Sample

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3 Approach & Methodology

3.1 Methodology Flows for the Fairview Creek study area were calculated using a rainfall-runoff model. The model chosen for use is an XPSWMM version 19.3.5 one dimensional (1D) hydrologic and hydraulic model. A 1D model uses governing equations to solve for depth of flow, which is the single dimension which gives the model its classification. When considering unsteady flows along structures – such as through culverts, around bridges, or over weirs – upstream and downstream boundary conditions are used in order to see the change in flow when water moves through them. XPSWMM is based on the EPA Storm Water Management Model (SWMM) developed in the 1970’s as a comprehensive urban runoff model for continuous and event-based simulation. XPSWMM was selected due to existing models of the study area having been developed previously in XPSWMM, for its user-friendly model development, report generation, ability to import and export GIS shapefiles, and data management tools. XPSWMM versions 8.52 and newer are nationally accepted hydrologic model that meets the minimum requirement of the National Flood Insurance Program (NFIP). Following NFIP guidelines, the model was calibrated to observed flows before calculating annual peak flood return interval flows.

3.1.1 Rainfall Rainfall data used in the calibration of the XPSWMM model was collected from the rain gage at the Portland- Troutdale Airport (KTTD). Data was gathered for two periods of record. The first period is from 12/7/2015 0:00 to 12/8/2015 16:30 and was used for calibration of the hydrology of the large sub-basin upstream of NE Glisan Street. The second period is a single day event on 2/28/2018 from 1:19 to 23:53 and was used for calibration of the study area sub-basin hydrology. Figure 3-2 and Figure 3-1 illustrate the measured rainfall for the two events.

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Portland Troutdale Airport Rain Gage 12/7/2015 0:00 to 12/8/2015 16:30

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KTTD Rain Gage December 2015 Portland Troutdale Airport Rain Gage 2/28/2018 1:19 to 23:53

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KTTD Rain Gage February 2018

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Design event storms were determined using the City of Portland Stormwater Management Manual as required by the City of Fairview and correspond to 24-hour rainfall depths. Table 3-1 outlines the design storm depths used for the hydrologic analysis. Values for the 50-year and 500-year 24-hour depths were interpolated using a logarithmic relationship between the given values. Table 3-1 Design Storm Events Return Annual Percent 24-hour Design Interval Chance Depth (inches) 2-year 50% 2.4 5-year 20% 2.9 10-year 10% 3.4 25-year 4% 3.9 50-year 2% 4.2* 100-year 1% 4.4 500-year 0.2% 5.4* * Interpolated Following City of Fairview requirements, all design storm events were given the temporal distribution of an NRCS Type 1A 24-hour unit hydrograph. This hydrograph was input in a tabular format into XPSWMM and multiplied by the respective design depth for each run to generate the input rainfall. Figure 3-3 illustrates a 25-year design storm with a Type 1A distribution.

25-year Type 1A Hydrograph

3.1.2 Rainfall Losses Rainfall losses are calculated in the XPSWMM runoff module using EPA SWMM Runoff methodology with Curve Number (CN) infiltration. This methodology differs from TR-20 and TR-55 CN methodology in that the SWMM method only accounts for infiltration losses, with abstraction accounted for using the depression storage parameter in the Runoff method.

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This method was chosen due to the ease of which the parameters for each sub-basin could be quantified from available GIS data. The overall calculated losses are dependent on several factors including underlying soil type, vegetative cover, and impervious area. Each of these factors are spatially discrete and available in GIS format through means of land cover inventory, USGS soil information, and zoning information. This allowed for batch calculation of each parameter for each sub-basin with relatively little effort while providing a simple means of reproduction.

3.1.2.1 Curve Numbers A composite CN was calculated for each sub-basin and quantified separately from the impervious area in the sub-basin. The composite CN was calculated using the weighted average of CN “areas” that lie within each sub-basin. These “areas” were taken from a GIS shapefile with spatially discrete CN patches determined using the hydrologic soil group of the underlying soil and the vegetative land cover shapefiles. The CN value of each patch corresponds to a CN determined using Table 2-2a and Table 2-2c from TR- 55. Table 3-2 outlines the cover types delineated within the watershed, and the corresponding CN values for each cover type based on hydrologic soil group. Impervious area is handled separately from the infiltration in Runoff methodology, therefore impervious areas within the basin were considered to be Open Space when accounting for the composite CN. Table 3-2 Vegetative Cover CN Values Vegetative Cover Type Hydrologic Soil Group (Good Condition) A B C D Brush 30 48 65 73 Woods 30 55 70 77 Woods-Grass Combination 32 58 72 79 Open Space 39 61 74 80 An initial abstraction fraction of 0.2 was applied for each sub-basin, following TR-55 guidance. Sensitivity analysis showed that changes to this value resulted in negligible change to the resulting sub-basin flow.

3.1.2.2 Impervious Area Impervious areas for each sub-basin within the study area were determined based on aerial photographs and corresponding land use as illustrated in Figure 3-4. Sub-basins were given a Cover ID corresponding to a land use cover category and given an impervious percentage based on that ID. These percentages were developed using an average of measured values for sample areas using aerial photos. Table 3-3 outlines the given land use cover categories and their corresponding impervious percentages. Table 3-3 Impervious Percentage By Land Use Cover GIS Cover Impervious Category ID Percentage Parks, Open Space PO 0% Undeveloped UN 21% Residential (Low Density) RL 42% Commercial (Partially Developed) CP 50% Residential (High Density) RH 71% Commercial (Low Density), Roadways CL 85% Industrial, Commercial (High Density), Highways CH 90% Buildings BD 100% Sub-basins outside the study area, and sub-basins with mixed use were given impervious percentages based on aerial photographs for those specific basins. Table 3-4 outlines the impervious percentages used for these special cases.

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Table 3-4 Impervious Percentage by Special Case Sub- Impervious Description Basin ID Percentage 125 63% Mixed use sub-basin 166 85% Salish Pond sub-basin 180 33.8% Arrata Rd upstream sub-basin 189 49.9% Wood Villiage south sub-basin 211 78.6% Wood Villiage north sub-basin 216 74% Glisan St Fujitsu Ponds upstream sub-basin 217 20% 223rd Ave upstream sub-basin 219 13.1% Glisan St Woodland Elementary upstream sub-basin

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Impervious Cover

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3.1.2.3 Depression Storage Depression storage is the initial abstraction by the process of surface ponding, surface wetting, interception and evaporation, and applies to both impervious and pervious cover. All depression storage must be filled before runoff begins and therefore influences the volume that is conveyed downstream. Depression storage controls the amount of runoff that immediately runs off of a surface. A percentage of Zero Detention Storage can be applied to represent an amount of impervious area that has no depression storage, and contributes 100% of its rainfall volume to surface runoff. Table 3-5 lists the depression storage parameters that were used in the model, which were set through recommendations outlined in Chapter 3 of the Storm Water Management Model Reference Manual, Volume I – Hydrology (Revised), dated January 2016. Table 3-5 Depression Storage Parameters Impervious Depression Pervious Depression Zero Detention Storage (inches) Storage (inches) Storage 0.0625 0.2500 25%

3.1.3 Sub-Basin Response Sub-basin response is calculated using EPA SWMM methodology within the XPSWMM Runoff module. In SWMM methodology, the sub-basin is modeled as a nonlinear reservoir with a rectangular surface. The sub-basin is modeled as having a uniform slope and width that drains to a single outlet. After inflow from precipitation and losses from infiltration and evaporation are accounted for, any excess ponding depth above the depression storage depth can become runoff. The resulting overland flow is assumed to consist of uniform flow within an existing rectangular channel, and is computed using Manning’s equation. The key variables that affect the response from each sub-basin are the basin width, slope, and the modeled roughness of the sub-basin.

3.1.3.1 Sub-Basin Width The width of each sub-basin was assumed to be a function of the longest length of flow within the sub- basin. This flow length was calculated for each basin using the LiDAR DEM which was processed in ArcMap to generate a raster dataset with the minimum flow length for each cell. To account for statistical error resulting from the difference in levels of detail between the DEM and the sub-basin delineation, the flow length for each sub-basin was calculated as the sum of two standard deviations from the mean, eliminating the effect of outlier values. These values were then rounded to the nearest whole foot and recorded in the sub-basin shapefile. Assuming a rectangular basin, the area of the sub-basin was then divided by the calculated flow length and rounded to the nearest whole foot to then determine the sub-basin width.

3.1.3.2 Sub-Basin Slope The slope of each sub-basin was calculated similarly to the sub-basin width, as the total drop across the sub-basin was calculated using the sum of two standard deviations from the mean of the elevation values in the DEM within the sub-basin. Again, this was done to eliminate the effect of outliers and account for the different levels of detail between the LiDAR DEM and the sub-basin delineation. This calculated drop was then divided by the previously calculated flow length and rounded to the nearest 0.01%.

3.1.3.3 Sub-Basin Roughness The roughness of a sub-basin is characterized by Manning’s ‘n’ values, corresponding to the roughness of pervious and impervious areas. For all sub-basins, a Manning’s ‘n’ value of 0.014 (asphalt paving) was used for impervious surfaces, and a value of 0.20 (light turf) was used for all pervious surfaces (Crawford and Linsley, 1966). A sensitivity analysis was conducted and showed that a 30% decrease in the impervious Manning’s ‘n’ value resulted in a roughly 3.3% increase in flow, and a 30% increase resulted in a roughly 2.6% decrease

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3.1.4 Routing XPSWMM uses full hydrodynamic routing within the Hydraulics module of the software. The software uses EXTRAN (Dynamic Wave) routing to model open channel and closed conduit networks in both dendritic and looped configurations. EXTRAN is based on the St. Venant equations for gradually varied one- dimensional flow, and has procedures for handling exceptional flow situations such as roll waves, bores, supercritical flow, and hydraulic jumps that would otherwise violate the assumption of gradually varied flow. The XPSWMM hydrologic model for Fairview Creek incorporates a full link-node representation of the physical condition of the study area; explicitly modeling Fairview Creek, the connected storm sewer pipe system, culverts, bridges, ponds, reservoirs, and control structures. The physical geometry of the real structure as well as appropriate Manning’s ‘n’ value is assigned to each link in the model, and used in the EXTRAN calculation to determine flow. Each link has a defined cross-sectional shape, length, slope, invert elevations, and Manning’s ‘n’ value. Each link also has the option of user-defined inlet and outlet losses to account for expansion, contraction, headwall losses, or other losses. Nodes at the upstream and downstream ends of each link have physical descriptions as well, but are generally limited to invert elevations and ground or rim elevations.

3.1.5 Channel Storage Channel storage is calculated at each link using the defined geometry of the link, including cross-sectional shape, length, slope, invert elevations, and Manning’s ‘n’ value. XPSWMM has options for built-in sections such as circular, and rectangular closed conduits or trapezoidal open channels. Additionally, the model has options for user-defined cross-sections including natural channel sections or special closed conduits.

3.1.6 Reservoir Storage A stage-storage relationship can be defined at a given node, and stage-storage curves are used for the representation of several ponds in the model. Additionally, two detention pipes within the storm sewer system of Fairview Creek were modeled as well. Table 3-6 summarizes the model objects used for reservoir storage. Table 3-6 Reservoir Storage Summary Component Detention Detention Depth/Diameter ID Type Type Volume (cu-ft) (feet) FVSTORM-04118S Node Surface 41,529 4.11 FVSTORM-04125S Node Surface 40,868 5.50 FVSTORM-04126S Node Surface 4,356 4.00 FVSTORM-04128S Node Surface 186,642 12.50 FVSTORM-04129S Node Surface 23,397 5.90 TFP Pond Node Surface 22,539 6.00 RDL-J Node Surface 858,000 10.00 Glisan7 Node Surface 1,484,340 17.30 W_OS_Pond Node Surface 3,808,668 15.00 E_OS_Pond Node Surface 7,546,116 15.00 1578 Link Pipe 1,885 4.00 1517 Link Pipe 2,702 4.00

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3.1.7 Calibration Approach Calibration of the model occurred by modifying the hydrology of the large upstream basins of the watershed as these basins possessed the greatest level of uncertainty. The sub-basins calibrated specifically were sub-basin 216, and sub-basin 180. Sub-basin 216 was calibrated separately as it was able to take advantage of the longer period of record for calibration, due to it being immediately upstream of the USGS gage at NE Glisan Street.

3.1.7.1 Sensitivity Analysis A sensitivity analysis was completed to find which hydrologic parameters were most likely to adjust model results. The sensitivity parameters that were checked are:  Area  Impervious Percentage  Width  Slope  Depression Storage  Manning’s ‘n’ Value  Curve Number (CN)  Initial Abstraction Factor The sensitivity analysis found that area and impervious percentage were the most sensitive catchment parameters with width and slope being less so by an order of magnitude. Pervious area Curve Number was the most sensitive of the infiltration parameters with the impervious Manning’s ‘n’ value being less so by an order of magnitude, and other values resulting in no change or negligible change. Table 3-7 summarizes the results of the sensitivity analysis. Table 3-7 Sensitivity Analysis Summary Varriance Sub-Basin Parameter -30% -20% -10% 0% +10% +20% +30% Catchment Parameters Area -27.5% -18.2% -9.1% - 8.9% 17.8% 26.5% % Impervious -27.5% -18.2% -9.1% - 8.9% 17.8% 26.5% Width -3.7% -2.3% -1.1% - 1.0% 1.8% 2.6% Slope -2.1% -0.9% -0.4% - 0.4% 0.8% 1.4% Infiltration Parameters Impervious Depression Storage 0.004% 0.004% - - - - - Pervious Depression Storage ------Impervious Manning's 'n' 3.3% 2.4% 0.7% - -0.7% -2.0% -2.6% Pervious Manning's 'n' ------Curve Number - - - - - 1.8% 18.5% Initial Abstraction Factor ------GIS mapping of the area’s storm sewer systems and the detailed LiDAR DEM resulted in the area of each sub-basin well within reasonable certainty. Therefore, the calibration occurred through modification of impervious area, width, and slope.

3.1.7.2 Sub-Basin 216 Sub-basin 216 encompasses roughly 2,182 acres of area upstream of NE Glisan Street. The gage at NE Glisan Street, at the downstream discharge point of the sub-basin, captured a large storm on December 7, 2015 that resulted in a peak flow at the gage with a roughly 25-year return interval. This storm was used as a reference for calibrating this watershed.

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Due to the size and complexity of the sub-basin, calibration was not able to be accomplished through changing sub-basin parameters alone. To achieve a reasonable representation of the sub-basin, it was modeled as two separate sub-basins and four hydrology routing links in the XPSWMM Runoff module. These routing links differ from the links in the Hydraulics module in that the link is used to compute lag time in the hydrograph rather than the hydraulic grade line at a node. The resulting calibration provided reasonable results that are illustrated in Figure 3-5.

NE Glisan Street Gage Calibration Results

3.1.7.3 Sub-Basin 180 Sub-basin 180 encompasses roughly 307 acres of area upstream of NE Arata Road. This sub-basin discharges to No-Name Creek which has a split-flow connection to Fairview Creek at NE Halsey Street and NE 223rd Avenue. Therefore, the calibration of this basin required review of both City gages at NE Sandy Blvd and I-84. A storm recorded on February 28, 2018 was used for calibration as it was the storm that resulted in the larges peak flows for both city gages during the period of record. This sub-basin, being smaller and less complex than sub-basin 216, only required modification to the sub- basin parameters to achieve reasonable calibration. The impervious area of the sub-basin was modified to achieve appropriate peak flows, and the sub-basin width and slope were modified to achieve appropriate peak timing. Figure 3-6 and Figure 3-7 illustrate the calibration results for the NE Sandy Blvd gage and I- 85 gage respectively.

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NE Sandy Blvd Gage Calibration Results

I-84 Gage Calibration Results

For this calibration, sub-basin 216 was not modeled, with the direct measured flow from the NE Glisan Street gage being input directly into the model.

3.2 Assumptions It was assumed, for the modeling of the watershed, that the boundary condition at Fairview Lake would remain static through each design storm with a fixed water surface elevation of 14 feet. This assumption is based on previous studies in the region, and the water surface of Fairview Lake and the flow in the receiving Columbia Slough are mechanically controlled by the Multnomah County Drainage District.

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3.3 Gages Data used to calibrate the model was gathered from two sources. The first source was USGS gage 14211814 located on Fairview Creek at NE Glisan Street with a record from May 1992 to the present. The second source is a pair of stream flow gages installed by the City of Fairview on Fairview Creek and on an adjacent drainage way called No-Name Creek. The City gages were located at NE Sandy Blvd on Fairview Creek and at I-84 on No-Name Creek. These gages were installed in early February 2018 and maintained active until May 2018. Table 3-8 lists the locations of the gages used for calibration. The gage type and recorded storm events are listed in the table. Table 3-8 Fairview Creek Gage Measurement Gauge Location in Gauge Locaction Type Storm Event Model Fairview Creek at NE Glisan St December 7, 2015 & FVSTORM-01451M Stream Flow (USGS Gauge 14211814) February 28, 2018 Fairview Creek at NE Sandy Blvd FVSTORM-01374S Stream Flow February 28, 2018 (City Gauge) No-name creek at I-84 FVSTORM-00914S Stream Flow February 28, 2018 (City Gauge) Figure 3-8 illustrates the location of the gages used.

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Gage Location Map

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3.4 Urbanization The Fairview Creek watershed is completely urbanized. This was accounted for in the impervious area percentage assigned to each sub-basin. Methodology used in estimating impervious percentage is documented in Section 3.1.2.2.

4 Discharge Comparison

Table 4-1 compares the 100-year (1% annual chance) peak discharges from the effective Flood Insurance Study (FIS) report for Multnomah County, dated February 1, 2019, at six locations along Fairview Creek. Proposed discharges will be used in place of effective discharges to account for the detailed modelling effort of the Fairview Creek watershed downstream of NE Glisan Street. Effective flows upstream of NE Glisan Street will remain the same. Table 4-1 100-year Discharge Comparison Basin Proposed FIS Change in Stream FIS Reference XS Area Discharge Discharge Discharge (acres) (cfs) (cfs) Fairview Creek At mouth 3734 465 490 -5.1% Fairview Creek At Sandy Boulevard 3220 376 430 -12.6% Fairview Creek At Banfield Expressway 3211 376 350 7.4% Fairview Creek At NE Halsey Street 2657 355 345 2.9% Fairview Creek At NE Glisan Street, below split flow 2257 305 145 110.3% Fairview Creek At NE Glisan Street, above split flow 2182 347 245 41.6%

5 Discharge Summary

Table 5-1 provides a summary of proposed discharges for the Fairview Creek study area. Table 5-1 Summary of Discharges Drainage Peak Discharges (cfs) Flooding Source and Location Area (sq- 10-Year 50-year 100-year 500-year mi) Fairview Creek At Mouth 5.8 333 435 465 529 At Sandy Boulevard 5.0 262 352 376 437 At Banfield Expressway 5.0 262 352 376 440 At NE Halsey Street 4.2 249 333 355 434 At NE Glisan Street, below split flow 3.5 206 284 305 412 At NE Glisan Street, above split flow 3.4 248 324 347 446

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6 References

1. Fairview Creek Stormwater Master Plan Addendum, April 2019. Cardno. Portland, Oregon. 2. City of Portland Stormwater Management Manual, August 2016. City of Portland Bureau of Environmental Services. Portland, Oregon. 3. TR-55 Urban Hydrology for Small Watersheds, Second Ed., June 1986. USDA NRCS Conservation Engineering Division. Washington, DC. 4. Storm Water Management Model Reference Manual, Volume I – Hydrology (Revised), January 2016. Rossman, L.A. and W.C. Huber. National Risk Management Laboratory, Office of Research and Development, U.S. Environmental Protection Agency. Cincinnati, OH. 5. Digital Simulation in Hydrology: Stanford Watershed Model IV, July 1966. Crawford, N.H. and R.K. Linsley. Civil Engineering Department, Stanford University. Palo Alto, CA.

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APPENDIX A DATA FILES

Hydrology Report Fairview Creek Bypass – Letter of Map Revision

Appendix A Data Files

XPSWMM Files Hydrology Model  1476-Fairvew Creek Hydrology.bak  1476-Fairvew Creek Hydrology.json  1476-Fairvew Creek Hydrology.mdb  1476-Fairvew Creek Hydrology.sqlite  1476-Fairvew Creek Hydrology.xml  1476-Fairvew Creek Hydrology.xp  1D  1476-Fairvew Creek Hydrology_2-Year > 1476-Fairvew Creek Hydrology_2-Year.dat > 1476-Fairvew Creek Hydrology_2-Year.hdr > 1476-Fairvew Creek Hydrology_2-Year.out > 1476-Fairvew Creek Hydrology_2-Year.res > 1476-Fairvew Creek Hydrology_2-Year.rnf > 1476-Fairvew Creek Hydrology_2-Year.syf > 1476-Fairvew Creek Hydrology_2-Year.syh > 1476-Fairvew Creek Hydrology_2-Year.syr > engineRuns.lck > SWMENG.VER > SWMPCTDONE.SCRATCH  1476-Fairvew Creek Hydrology_5-Year > 1476-Fairvew Creek Hydrology_5-Year.dat > 1476-Fairvew Creek Hydrology_5-Year.hdr > 1476-Fairvew Creek Hydrology_5-Year.out > 1476-Fairvew Creek Hydrology_5-Year.res > 1476-Fairvew Creek Hydrology_5-Year.rnf > 1476-Fairvew Creek Hydrology_5-Year.syf > 1476-Fairvew Creek Hydrology_5-Year.syh > 1476-Fairvew Creek Hydrology_5-Year.syr

March 2020 Cardno A-1 1476-Hydrology Report.docx Hydrology Report Fairview Creek Bypass – Letter of Map Revision

> engineRuns.lck > SWMENG.VER > SWMPCTDONE.SCRATCH  1476-Fairvew Creek Hydrology_10-Year > 1476-Fairvew Creek Hydrology_10-Year.dat > 1476-Fairvew Creek Hydrology_10-Year.hdr > 1476-Fairvew Creek Hydrology_10-Year.out > 1476-Fairvew Creek Hydrology_10-Year.res > 1476-Fairvew Creek Hydrology_10-Year.rnf > 1476-Fairvew Creek Hydrology_10-Year.syf > 1476-Fairvew Creek Hydrology_10-Year.syh > 1476-Fairvew Creek Hydrology_10-Year.syr > engineRuns.lck > SWMENG.VER > SWMPCTDONE.SCRATCH  1476-Fairvew Creek Hydrology_25-Year > 1476-Fairvew Creek Hydrology_25-Year.dat > 1476-Fairvew Creek Hydrology_25-Year.hdr > 1476-Fairvew Creek Hydrology_25-Year.out > 1476-Fairvew Creek Hydrology_25-Year.res > 1476-Fairvew Creek Hydrology_25-Year.rnf > 1476-Fairvew Creek Hydrology_25-Year.syf > 1476-Fairvew Creek Hydrology_25-Year.syh > 1476-Fairvew Creek Hydrology_25-Year.syr > engineRuns.lck > SWMENG.VER > SWMPCTDONE.SCRATCH  1476-Fairvew Creek Hydrology_50-Year > 1476-Fairvew Creek Hydrology_50-Year.dat > 1476-Fairvew Creek Hydrology_50-Year.hdr > 1476-Fairvew Creek Hydrology_50-Year.out > 1476-Fairvew Creek Hydrology_50-Year.res > 1476-Fairvew Creek Hydrology_50-Year.rnf > 1476-Fairvew Creek Hydrology_50-Year.syf > 1476-Fairvew Creek Hydrology_50-Year.syh

March 2020 Cardno A-2 1476-Hydrology Report.docx Hydrology Report Fairview Creek Bypass – Letter of Map Revision

> 1476-Fairvew Creek Hydrology_50-Year.syr > engineRuns.lck > SWMENG.VER > SWMPCTDONE.SCRATCH  1476-Fairvew Creek Hydrology_100-Year > 1476-Fairvew Creek Hydrology_100-Year.dat > 1476-Fairvew Creek Hydrology_100-Year.hdr > 1476-Fairvew Creek Hydrology_100-Year.out > 1476-Fairvew Creek Hydrology_100-Year.res > 1476-Fairvew Creek Hydrology_100-Year.rnf > 1476-Fairvew Creek Hydrology_100-Year.syf > 1476-Fairvew Creek Hydrology_100-Year.syh > 1476-Fairvew Creek Hydrology_100-Year.syr > engineRuns.lck > SWMENG.VER > SWMPCTDONE.SCRATCH  1476-Fairvew Creek Hydrology_500-Year > 1476-Fairvew Creek Hydrology_500-Year.dat > 1476-Fairvew Creek Hydrology_50-Year.hdr > 1476-Fairvew Creek Hydrology_500-Year.out > 1476-Fairvew Creek Hydrology_500-Year.res > 1476-Fairvew Creek Hydrology_500-Year.rnf > 1476-Fairvew Creek Hydrology_500-Year.syf > 1476-Fairvew Creek Hydrology_500-Year.syh > 1476-Fairvew Creek Hydrology_500-Year.syr > engineRuns.lck > SWMENG.VER > SWMPCTDONE.SCRATCH December 7, 2015 Calibration Model  1476-Calibration-Dec7.bak  1476-Calibration-Dec7.json  1476-Calibration-Dec7.mdb  1476-Calibration-Dec7.sqlite  1476-Calibration-Dec7.xml

March 2020 Cardno A-3 1476-Hydrology Report.docx Hydrology Report Fairview Creek Bypass – Letter of Map Revision

 1476-Calibration-Dec7.xp  1D  1476-Calibration-Dec7_December 7 > 1476-Calibration-Dec7_December 7.dat > 1476-Calibration-Dec7_December 7.hdr > 1476-Calibration-Dec7_December 7.lck > 1476-Calibration-Dec7_December 7.out > 1476-Calibration-Dec7_December 7.res > 1476-Calibration-Dec7_December 7.rnf > 1476-Calibration-Dec7_December 7.syf > 1476-Calibration-Dec7_December 7.syh > 1476-Calibration-Dec7_December 7.syr > SWMENG.VER > SWMPCTDONE.SCRATCH February 28, 2018 Calibration Model  1476-Calibration-Feb28.bak  1476-Calibration-Feb28.json  1476-Calibration-Feb28.mdb  1476-Calibration-Feb28.sqlite  1476-Calibration-Feb28.xml  1476-Calibration-Feb28.xp  1D  1476-Calibration-Feb28_February 28 > 1476-Calibration-Feb28_February 28.dat > 1476-Calibration-Feb28_February 28.hdr > 1476-Calibration-Feb28_February 28.lck > 1476-Calibration-Feb28_February 28.out > 1476-Calibration-Feb28_February 28.res > 1476-Calibration-Feb28_February 28.rnf > 1476-Calibration-Feb28_February 28.syf > 1476-Calibration-Feb28_February 28.syh > 1476-Calibration-Feb28_February 28.syr > SWMENG.VER > SWMPCTDONE.SCRATCH

March 2020 Cardno A-4 1476-Hydrology Report.docx Hydrology Report Fairview Creek Bypass – Letter of Map Revision

 Calibration Flows  Flow Data – Fairview Creek – 2018-02-28.csv  Flow Data – No-Name Creek – 2018-02-28.csv

March 2020 Cardno A-5 1476-Hydrology Report.docx

About Cardno Cardno is an ASX-200 professional infrastructure and environmental services company, with expertise in the development and improvement of physical and social infrastructure for communities around the world. Cardno’s team includes leading professionals who plan, design, manage, and deliver sustainable projects and community programs. Cardno is an international company listed on the Australian Securities Exchange [ASX:CDD].

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Hydraulics Report Fairview Creek – Letter of Map Revision

March 2020

Prepared For

City of Fairview, Oregon

March 2020

Hydraulics Report Fairview Creek – Letter of Map Revision

Contact Information Document Information Cardno 6720 SW Macadam Ave, Suite #150 Portland, Oregon 97219 Telephone: 503.419.2500 Facsimile: 503.419.2600 [email protected] www.cardno.com

Prepared for City of Fairview, Oregon Project Name Hydraulics Report Fairview Creek – Letter of Map Revision File Reference 1476-Hydraulics Report.docx Job Reference 21914760 Date March 2020

Document History

Version Effective Date Description of Revision Prepared by Reviewed by 1.0 02/26/2020 Initial Draft Daniel Child Cedomir Jesic 1.1 03/10/2020 City Submittal Draft Daniel Child Cedomir Jesic 1.2 03/26/2020 Final Draft Daniel Child Cedomir Jesic

March 2020 Cardno Document Information i D:\Fairview LOMR\1476-Hydraulics Report.docx Hydraulics Report Fairview Creek – Letter of Map Revision

Table of Contents 1 Introduction ...... 1-1 1.1 Study Area ...... 1-1 1.2 Purpose of Study ...... 1-2 1.3 Type of Flooding ...... 1-2 1.4 Flooding History ...... 1-2 2 Methodology and Modeling ...... 2-3 2.1 Methodology ...... 2-3 2.2 Topography ...... 2-3 2.2.1 Datum and Survey ...... 2-3 2.2.2 Cross-Sections ...... 2-3 2.3 Boundary Conditions ...... 2-4 2.4 Structures ...... 2-4 2.4.1 NE Barr Road Bridge ...... 2-4 2.4.2 NE Halsey Street Culvert ...... 2-4 2.4.3 NE Fairview Avenue Culvert ...... 2-4 2.4.4 Walnut Lane Bridge...... 2-4 2.4.5 SE Matney Street Bridge ...... 2-4 2.5 Ineffective and Storage Areas ...... 2-5 2.6 Manning’s Roughness Values ...... 2-5 2.7 Split and Diverted Flow ...... 2-5 2.8 Floodway Analysis ...... 2-5 3 Effective Elevation Comparison ...... 3-6 4 References ...... 4-8

Appendices Appendix A Input & Output

Tables Table 2-1 Manning’s ‘n’ Values ...... 2-5 Table 3-1 Fairview Creek Elevation Comparison ...... 3-7

Figures Vicinity Map ...... 1-1

March 2020 Cardno Table of Contents ii D:\Fairview LOMR\1476-Hydraulics Report.docx Hydraulics Report Fairview Creek – Letter of Map Revision

Acronyms DTM Digital Terrain Model FIS Flood Insurance Study HEC-RAS Hydrologic Engineering Center River Analysis System HU Hydrologic Unit LiDAR Light Detection and Ranging NAD83 North American Datum of 1983 NAVD88 North American Vertical Datum of 1988 NFIP National Flood Insurance Program OCRS Oregon Coordinate Reference System USGS United States Geologic Survey WSE Water Surface Elevation

March 2020 Cardno Table of Contents iii D:\Fairview LOMR\1476-Hydraulics Report.docx Hydraulics Report Fairview Creek – Letter of Map Revision

1 Introduction

1.1 Study Area The Fairview Creek Watershed is in Multnomah County, Oregon and is contained within USGS Hydrologic Unit (HU) 170900120201 (Columbia Slough). Interstate 84 runs perpendicular to the creek through the northern half of the watershed, with the creek running through the cities of Gresham and Fairview. The watershed terminates at Fairview Lake which is controlled by weir gates and discharges to the Columbia Slough. Water levels in the Slough and the lake are mechanically regulated by Multnomah County Drainage District. The Fairview Creek study area proposed for floodplain remapping extends from effective cross-section AD approximately 75 feet north of SE Matney Street to effective cross-section AO approximately 350 feet south of NE Halsey Street.

Vicinity Map

March 2020 Cardno Introduction 1-1 D:\Fairview LOMR\1476-Hydraulics Report.docx Hydraulics Report Fairview Creek – Letter of Map Revision

1.3 Type of Flooding The flooding experienced through the study area is entirely riverine with no tidal influences. Fairview Creek terminates at Fairview Lake, roughly 73 miles east of the Pacific Ocean and roughly 90 miles southeast of the mouth of the Columbia River. Fairview Lake is not a large enough water body to experience significant tidal shift such that tidal effects from the lake would have a meaningful impact on the results of the modeling.

March 2020 Cardno Introduction 1-2 D:\Fairview LOMR\1476-Hydraulics Report.docx Hydraulics Report Fairview Creek – Letter of Map Revision

2 Methodology and Modeling

2.1 Methodology Hydraulic modeling of the study area was conducted using the USACE Hydrologic Engineering Center River Analysis System (HEC-RAS) version 5.0.5. The models utilize a one-dimensional (1D) geometry model developed to analyze the 10-, 4-, 2-, 1-, and 0.2-percent-annual-chance flood events for the Fairview Creek Study Area. No effective model could be obtained for the modeled section as the effective model has not been kept on file at the City of Fairview or the City of Gresham.

2.2 Topography

2.2.1 Datum and Survey Survey data was collected using a variety of datums with the ultimate horizontal datum used for this study being the Oregon Coordinate Reference System (OCRS, Portland Zone projection using the North American Datum of 1983 (NAD83) and the ultimate vertical datum being the North American Vertical Datum of 1988 (NAVD88). Cross-sectional data was surveyed using the Oregon Coordinate Reference System (OCRS), Portland Zone, with a Lambert Conformal Conic Projection. The system used the North American Datum of 1983 (NAD83) and the North American Vertical Datum of 1988 (NAVD88). Topographic data used for mapping the special flood hazard area was derived from a Digital Terrain Model (DTM) developed using Aerial Light Detection and Ranging (LiDAR). This LiDAR was collected in 2014 for the Portland Metro area which includes Washington, Multnomah, and Clackamas Counties and is referenced to the Oregon State Plane North projected coordinate system using the NAD83 horizontal datum and NAVD88 vertical datum. This data was projected to the OCRS Portland Zone projection for use in mapping. Additional survey data was used from the “Northbrook Village” project which was translated to the OCRS system by rotating and translating the data until the basis of bearing line: …The south line, per monuments found and held per partition plat No. 1995-41, records of Multnomah County… Aligned with the same line surveyed on the OCRS system. The vertical datum for this survey was already based on a known point: …Control point ‘STOP’ (PID RD0002) being a disk stamped ‘STOP 1956’ set in a concrete monument located along the south side of U.S. Highway 30 about 0.7 miles west-northwest of Troutdale, about 200 yards east of the first railroad overpass west of the Troutdale junction. The elevation is 36.38’, NAVD 1988…

2.2.2 Cross-Sections Cross-sections were placed in representative locations approximately 100 feet apart where possible. Cross-section geometries were obtained several sources, details of which can be found in Section 2.2.1. Survey data was used for in-channel geometry with overbanks measured from a DTM. In sections where the distance between cross-sections exceeded 100 feet, an interpolated cross-section was inserted to fill the gap in order to preserve model stability. Channel geometry was interpolated between the cross- sections upstream and downstream using the built-in interpolation routines in HEC-RAS, and overbank geometry was developed from a DTM.

March 2020 Cardno Methodology and Modeling 2-3 D:\Fairview LOMR\1476-Hydraulics Report.docx Hydraulics Report Fairview Creek – Letter of Map Revision

2.3 Boundary Conditions Upstream and downstream boundary conditions were both calculated based on normal depth flow, with provided energy slopes equivalent to the mean channel slope upstream or downstream of the boundary condition. Although the model ties in to effective studies upstream and downstream of the study area, known water surface elevations (WSE) were not used due to the discrepancy of hydrologic data between the effective models and the proposed model.

2.4 Structures Five structures are modeled as part of this study. These structures include the NE Barr Rd bridge, NE Halsey St culvert, NE Fairview Ave culvert, Walnut Ln bridge, SE Matney St bridge, and an inline weir approximately 200 feet upstream of NE Barr Rd. For all structures, expansion and contraction coefficients were set to 0.3 and 0.5 respectively upstream and downstream of each structure, with all other expansion and contraction coefficient values set to 0.1 and 0.3 respectively. Detailed structure data is presented in Appendix A.

2.4.1 NE Barr Road Bridge Geometric data for this bridge was taken from the City of Fairview Consolidated Stormwater Master Plan XPSWMM model initially developed by Oakley Engineering in 1993, and subsequently updated by CH2M Hill in 1997 and 2000, and by Crawford Engineering Associates in 2006. This model indicated that the structure at NE Barr Rd is a 11.7-foot span by 4-foot rise box culvert at a slope of 1%. However, asset management information from Multnomah County indicates that this bridge is a concrete slab supported on concrete abutments rather than a culvert. The final geometry used for this analysis models the structure as a bridge with an upstream low chord elevation of 158.71, a downstream low chord elevation of 158.41 feet, an upstream span of 12.7 feet, and a downstream span of 11.5 feet to account for skew relative to the surveyed cross-sections.

2.4.2 NE Halsey Street Culvert Geometric data for this culvert was obtained from as-built plans from Multnomah County dated May 1996. The structure is a 130-foot long, 16-foot span, 5-foot rise, precast rectangular concrete culvert with an open bottom, supported on concrete spread footings. The culvert sits at a 45° skew normal to the centerline of NE Halsey St, and was constructed with 10-foot wing walls flared at 30° on the upstream and downstream ends of the culvert.

2.4.3 NE Fairview Avenue Culvert Geometric data for this culvert was obtained from the same as-built plans from Multnomah County as the NE Halsey St culvert. This culvert has the same span and rise, but has a total length of 80 feet and sits at a 17° skew normal to the centerline of NE Fairview Ave (known also as NE 223rd Ave) and was also constructed with 10-foot wing walls angled at 30° on the upstream and downstream ends of the culvert.

2.4.4 Walnut Lane Bridge Geometric data for this bridge was obtained from survey conducted by Cardno in the summer of 2018. The structure appears to be a precast 3-sided culvert, likely supported by concrete spread footings. The structure has an approximately 11-foot span and 4-foot rise with concrete wing walls flared at 30° on both upstream and downstream ends.

2.4.5 SE Matney Street Bridge Geometric data for this bridge was obtained from survey conducted by Cardno in the summer of 2018. The structure appears to be a precast 3-sided culvert, likely supported by concrete spread footings. The

March 2020 Cardno Methodology and Modeling 2-4 D:\Fairview LOMR\1476-Hydraulics Report.docx Hydraulics Report Fairview Creek – Letter of Map Revision structure has an approximately 11-foot span and 5.5-foot rise with concrete wing walls flared at 30° on both upstream and downstream ends.

2.5 Ineffective and Storage Areas Ineffective flow areas were modeled in HEC-RAS in areas where the influence of structures would lead to the formation of eddies, in overbanks areas that would not contribute to flow until a defined water surface elevation was reached, or in overbank depressions that otherwise lack a physical flow path. For cross- sections upstream and downstream of structures, it was assumed that flow influence lines would be at 1:1 to the structure geometry as the flow contracts/expands. Ineffective flow areas were set to permanent if that region of the cross-section lacked a physical flow path below the defined elevation. No storage areas were used in this model.

2.6 Manning’s Roughness Values Manning’s ‘n’ values were estimated for each cross-section based on field inspection during the survey of the cross-sections. Values were chosen from those provided in Table 3-1 from the HEC-RAS Hydraulic Reference Manual for the “Normal” condition. Values used in the modeling of Fairview Creek can be found in Table 2-1.

Table 2-1 Manning’s ‘n’ Values Manning's Channel Condition Description 'n' value Main Channel Some stones and weeds, straight, full, no rifts or deep pools 0.035 Floodplain Medium to dense brush in winter 0.070 Pasture, no brush, short grass (lawn) 0.030 Asphalt, rough 0.016 Concrete, trowel finish 0.013

2.7 Split and Diverted Flow Split flow occurs approximately 200 feet upstream of NE Barr Rd, with some flow being diverted around NE Barr Rd, controlled by a lateral concrete weir. Division of flow was determined using the XPSWMM hydrologic model developed for the mapping effort. The details of this model are documented in the Hydrology Report accompanying this submittal.

2.8 Floodway Analysis The floodway analysis was conducted using the HEC-RAS hydraulic model. Initial encroachments were determined using the built-in HEC-RAS encroachment analysis (Method 4) assigning the maximum rise to 1 foot per National Flood Insurance Program (NFIP) requirements. Encroachment stations were then adjusted by hand in order to bring the total rise in the base flood elevation to less than or equal to 1 foot as the automatic process yielded a rise greater than 1 foot for some cross-sections.

March 2020 Cardno Methodology and Modeling 2-5 D:\Fairview LOMR\1476-Hydraulics Report.docx Hydraulics Report Fairview Creek – Letter of Map Revision

3 Effective Elevation Comparison

Table 3-1 compares the proposed base flood elevations with the effective elevations published in the Flood Insurance Study (FIS). As a whole, the study shows a reduction in base flood elevations across the study area with the greatest reduction being 6.3 feet and the greatest rise being 0.6 feet. The section between NE Fairview Ave and NE Halsey St show the largest reduction in elevation, likely due to the reduction in flows as well as the inclusion of the larger culverts under NE Fairview Ave and NE Halsey St constructed by Multnomah County since the last update to this reach of Fairview Creek.

March 2020 Cardno Effective Elevation Comparison 3-6 D:\Fairview LOMR\1476-Hydraulics Report.docx Hydraulics Report Fairview Creek – Letter of Map Revision

Table 3-1 Fairview Creek Elevation Comparison Approximate FIS Cross- Effective Base Proposed Base Modeled Base Δ Section River Station Flood Elevation Flood Elevation Flood Elevation ID feet (NGVD88) feet (NGVD88) feet (NGVD88) feet (NGVD88) AP 9517 165.4 AO 9117* 162.6 9246 162.0 9145 161.5 Barr Rd Bypass Diversion 9007 159.3 8904 158.4 AN 8727* 160.2 158.2 -2.0 Barr Rd AM 8697* 159.7 157.0 -2.7 8861 157.0 Confluence with Barr Rd Bypass 8843 156.6 NE Halsey St 8666 154.1 AL 8527 159.5 154.0 -5.5 8479 153.1 AK 8392* 159.4 153.1 -6.3 8429 152.9 AJ 8337 158.9 152.9 -6.0 NE Fairview Ave 8324 152.5 AI 8185 152.4 152.3 -0.1 8184 151.9 8044 151.5 7946 151.2 7859 150.7 AH 7835 151.5 150.2 -1.3 7788 149.7 7715 150.1 AG 7665 151.3 150.1 -1.2 7630 150.1 7537 150.0 AF 7532 150.8 150.0 -0.8 Walnut Ln 7520 147.9 AE 7305* 143.8 142.0 -1.8 7317 142.0 SE Matney St 7287 139.6 AD 7180* 134.9 135.5 0.6 7206 133.6 AC 6965 132.7 * FIS station does not align with physical mapped location

March 2020 Cardno Effective Elevation Comparison 3-7 D:\Fairview LOMR\1476-Hydraulics Report.docx Hydraulics Report Fairview Creek – Letter of Map Revision

4 References

1. Brunner, G. W. (2016). River Analysis System Hydraulic Reference Manual (Version 5.0). Davis, CA: US Army Corps of Engineers Hydrologic Engineering Center (HEC) 2. Jesic, C. & Child, D. (2020). Hydrology Report for Fairview Creek – Letter of Map Revision. Portland, OR: Cardno

March 2020 Cardno References 4-8 D:\Fairview LOMR\1476-Hydraulics Report.docx

Fairview Creek – Letter of Map Revision

APPENDIX A INPUT & OUTPUT

Hydraulics Report Fairview Creek – Letter of Map Revision

Appendix A Input & Output

 HEC-RAS Standard Table 1  HEC-RAS Profiles  Field Photographs

March 2020 Cardno A-1 D:\Fairview LOMR\1476-Hydraulics Report.docx River: Fairview Creek HEC-RAS Plan: Existing Standard Table 1

Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) Fairview 9246 10-YR 248 158.46 161.56 161.56 162.43 0.010868 8.32 45.31 37.33 0.88 Fairview 9246 50-YR 332 158.46 161.96 161.96 162.98 0.011144 9.22 56.97 41.34 0.91 Fairview 9246 100-YR 354 158.46 162.03 162.03 163.12 0.011612 9.54 59.11 42.38 0.93 Fairview 9246 500-YR 471 158.46 162.58 162.58 163.77 0.01078 10.21 77.86 53.7 0.92

Fairview 9145 10-YR 248 157.88 160.98 160.78 161.25 0.005056 5.55 110.03 112.51 0.59 Fairview 9145 50-YR 332 157.88 161.38 160.89 161.61 0.004189 5.53 162.29 149.95 0.55 Fairview 9145 100-YR 354 157.88 161.48 160.98 161.7 0.003968 5.49 177.27 159.06 0.54 Fairview 9145 500-YR 471 157.88 161.89 161.3 162.07 0.003104 5.26 247.11 174.48 0.49

Barr Bypass 186 10-YR 21.04 158 159.69 158.34 159.8 0.011021 2.73 7.71 24.67 0.58 Barr Bypass 186 50-YR 44.88 158 160.14 158.34 160.34 0.00943 3.53 12.73 27.5 0.58 Barr Bypass 186 100-YR 51.21 158 160.25 158.34 160.46 0.009153 3.68 13.9 28.16 0.58 Barr Bypass 186 500-YR 87.46 158 160.75 158.34 161.06 0.008817 4.51 19.38 32.67 0.6

Barr Bypass 185 Inl Struct

Barr Bypass 123 10-YR 21.04 157.36 158.4 157.87 158.43 0.002966 1.55 13.56 16.59 0.3 Barr Bypass 123 50-YR 44.88 157.36 158.91 158.16 158.97 0.00298 1.96 22.85 19.61 0.32 Barr Bypass 123 100-YR 51.21 157.36 159.02 158.22 159.09 0.002957 2.04 25.14 20.28 0.32 Barr Bypass 123 500-YR 87.46 157.36 159.55 158.55 159.64 0.002981 2.39 36.66 23.38 0.34

Barr Bypass 82 10-YR 21.04 156.86 157.79 157.79 158.07 0.037302 4.22 4.99 9.02 1 Barr Bypass 82 50-YR 44.88 156.86 158.18 158.18 158.58 0.032719 5.09 8.82 10.79 0.99 Barr Bypass 82 100-YR 51.21 156.86 158.25 158.25 158.69 0.033008 5.31 9.65 11.13 1.01 Barr Bypass 82 500-YR 87.46 156.86 158.67 158.66 159.22 0.029603 5.96 14.68 13.03 0.99

Barr Bypass 31 10-YR 21.04 155.61 156.98 156.44 157.04 0.003869 1.91 11.02 11.76 0.35 Barr Bypass 31 50-YR 44.88 155.61 157.67 156.8 157.75 0.003182 2.24 20 14.24 0.33 Barr Bypass 31 100-YR 51.21 155.61 157.85 156.88 157.93 0.002926 2.26 22.63 14.89 0.32 Barr Bypass 31 500-YR 87.46 155.61 158.71 157.27 158.8 0.00222 2.38 36.72 17.97 0.29

Fairview-Barr 9007 10-YR 226.96 155.94 158.79 158.74 159.8 0.014954 8.09 28.53 14.26 0.96 Fairview-Barr 9007 50-YR 287.12 155.94 159.14 159.14 160.33 0.014749 8.77 33.93 16.82 0.97 Fairview-Barr 9007 100-YR 303.79 155.94 159.25 159.25 160.46 0.014406 8.9 35.72 18.02 0.97 Fairview-Barr 9007 500-YR 384.54 155.94 159.76 159.76 161.06 0.012292 9.26 46.57 24.05 0.92

Fairview Creek LOMR Page 1 of 8 River: Fairview Creek HEC-RAS Plan: Existing Standard Table 1

Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) Fairview-Barr 8955.50* 10-YR 226.96 154.92 158.05 157.99 159.01 0.015132 7.87 28.85 13.86 0.96 Fairview-Barr 8955.50* 50-YR 287.12 154.92 158.5 158.38 159.53 0.013764 8.11 35.42 14.99 0.93 Fairview-Barr 8955.50* 100-YR 303.79 154.92 158.62 158.48 159.66 0.013296 8.17 37.22 15.56 0.92 Fairview-Barr 8955.50* 500-YR 384.54 154.92 159.18 158.91 160.27 0.011318 8.38 46.66 18.43 0.87

Fairview-Barr 8904 10-YR 226.96 153.89 157.72 157.16 158.34 0.0083 6.32 35.9 15 0.72 Fairview-Barr 8904 50-YR 287.12 153.89 158.24 157.55 158.9 0.007671 6.53 43.96 16.36 0.7 Fairview-Barr 8904 100-YR 303.79 153.89 158.37 157.66 159.05 0.007492 6.57 46.24 16.72 0.7 Fairview-Barr 8904 500-YR 384.54 153.89 159.01 158.11 159.71 0.00666 6.7 57.45 19.34 0.67

Fairview-Barr 8883 Bridge

Fairview-Barr 8861 10-YR 226.96 153.95 156.51 156.51 157.41 0.01627 7.62 29.79 16.64 1 Fairview-Barr 8861 50-YR 287.12 153.95 156.86 156.86 157.86 0.01559 8.02 35.78 17.81 1 Fairview-Barr 8861 100-YR 303.79 153.95 156.95 156.95 157.97 0.015437 8.12 37.39 18.11 1 Fairview-Barr 8861 500-YR 384.54 153.95 158.29 157.33 158.84 0.005417 5.93 64.88 22.64 0.62

Fairview-Halsey 8843 10-YR 248 152.67 156 155.53 156.76 0.007294 7.44 40.85 30.49 0.74 Fairview-Halsey 8843 50-YR 332 152.67 156.51 156.05 157.46 0.007559 8.38 49.02 32.74 0.78 Fairview-Halsey 8843 100-YR 355 152.67 156.64 156.17 157.64 0.007618 8.61 51.09 33.31 0.78 Fairview-Halsey 8843 500-YR 472 152.67 157.25 156.76 158.5 0.007853 9.67 60.87 36 0.82

Fairview-Halsey 8755 Bridge

Fairview-Halsey 8666 10-YR 248 150.88 153.68 153.32 154.32 0.008362 6.48 40.11 21.5 0.76 Fairview-Halsey 8666 50-YR 332 150.88 153.98 153.75 154.87 0.009704 7.6 46.94 23.15 0.83 Fairview-Halsey 8666 100-YR 355 150.88 154.1 153.85 155.01 0.009546 7.75 49.62 23.76 0.83 Fairview-Halsey 8666 500-YR 472 150.88 154.71 154.37 155.73 0.008214 8.24 65.21 27.07 0.8

Fairview-Halsey 8572.50* 10-YR 248 149.93 153.27 152.37 153.68 0.004011 5.18 51.96 23.55 0.54 Fairview-Halsey 8572.50* 50-YR 332 149.93 153.32 152.8 154.02 0.006822 6.82 52.97 23.75 0.71 Fairview-Halsey 8572.50* 100-YR 355 149.93 153.46 152.91 154.18 0.006592 6.92 56.38 24.43 0.7 Fairview-Halsey 8572.50* 500-YR 472 149.93 154.25 153.41 155 0.005115 7.12 77.14 28.21 0.64

Fairview-Halsey 8479 10-YR 253 148.99 153.1 151.53 153.36 0.001913 4.14 69.92 26.85 0.39 Fairview-Halsey 8479 50-YR 340 148.99 152.92 151.95 153.44 0.004161 5.9 65.16 26.02 0.57 Fairview-Halsey 8479 100-YR 364 148.99 153.08 152.07 153.61 0.004052 6 69.31 26.74 0.57 Fairview-Halsey 8479 500-YR 485 148.99 153.97 152.59 154.53 0.003175 6.18 95.14 30.86 0.52

Fairview Creek LOMR Page 2 of 8 River: Fairview Creek HEC-RAS Plan: Existing Standard Table 1

Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) Fairview-Halsey 8429 10-YR 253 148.11 153.04 151.03 153.26 0.001427 3.94 77.9 27.99 0.34 Fairview-Halsey 8429 50-YR 340 148.11 152.76 151.51 153.25 0.003318 5.74 70.31 26.56 0.51 Fairview-Halsey 8429 100-YR 364 148.11 152.92 151.64 153.42 0.003286 5.87 74.59 27.37 0.51 Fairview-Halsey 8429 500-YR 485 148.11 153.85 152.21 154.38 0.002716 6.12 102.16 32.14 0.48

Fairview-Halsey 8377 Bridge

Fairview-Halsey 8324 10-YR 253 147.52 151.86 150.02 152.07 0.001589 3.82 75.34 28.52 0.35 Fairview-Halsey 8324 50-YR 340 147.52 152.37 150.46 152.66 0.001803 4.43 90.53 30.95 0.38 Fairview-Halsey 8324 100-YR 364 147.52 152.49 150.58 152.8 0.001861 4.59 94.37 31.53 0.39 Fairview-Halsey 8324 500-YR 485 147.52 153.04 151.13 153.45 0.002135 5.32 112.44 34.14 0.42

Fairview-Halsey 8184 10-YR 253 147.19 151.34 150.46 151.71 0.003467 5.17 63.45 31.47 0.51 Fairview-Halsey 8184 50-YR 340 147.19 151.79 150.9 152.25 0.003725 5.85 78.34 34.18 0.54 Fairview-Halsey 8184 100-YR 364 147.19 151.9 151 152.38 0.003818 6.03 81.95 34.81 0.55 Fairview-Halsey 8184 500-YR 485 147.19 152.36 151.51 152.98 0.004266 6.89 98.76 37.59 0.59

Fairview-Halsey 8044 10-YR 257 147.46 150.91 149.9 151.24 0.003139 4.72 66.28 42.23 0.49 Fairview-Halsey 8044 50-YR 346 147.46 151.36 150.38 151.75 0.003249 5.28 87.12 51.6 0.51 Fairview-Halsey 8044 100-YR 369 147.46 151.46 150.5 151.87 0.003271 5.4 92.68 54.86 0.51 Fairview-Halsey 8044 500-YR 490 147.46 151.92 151.03 152.4 0.00343 6.01 121.37 69.27 0.53

Fairview-Halsey 7946 10-YR 257 147.69 150.58 149.8 150.9 0.003786 4.65 67.73 47.97 0.52 Fairview-Halsey 7946 50-YR 346 147.69 151.05 150.21 151.41 0.003535 5.04 92.64 59.38 0.52 Fairview-Halsey 7946 100-YR 369 147.69 151.16 150.3 151.52 0.003498 5.13 99.32 63.65 0.52 Fairview-Halsey 7946 500-YR 490 147.69 151.66 150.76 152.05 0.003245 5.47 136.97 225.55 0.51

Fairview-Halsey 7859 10-YR 257 145.66 150.08 148.97 150.38 0.002814 4.74 81.47 52.02 0.45 Fairview-Halsey 7859 50-YR 346 145.66 150.56 149.59 150.9 0.002873 5.21 108.43 130.49 0.46 Fairview-Halsey 7859 100-YR 369 145.66 150.66 149.69 151.02 0.002913 5.34 115.01 152.81 0.46 Fairview-Halsey 7859 500-YR 490 145.66 151.23 150.17 151.57 0.002657 5.56 158.64 267.42 0.45

Fairview-Halsey 7788 10-YR 257 145.99 149.11 149.11 149.97 0.011796 7.75 43.59 33.22 0.87 Fairview-Halsey 7788 50-YR 346 145.99 149.58 149.58 150.49 0.010643 8.25 61.11 42.54 0.85 Fairview-Halsey 7788 100-YR 369 145.99 149.68 149.68 150.61 0.01042 8.36 65.76 44.69 0.85 Fairview-Halsey 7788 500-YR 490 145.99 150.05 150.05 151.16 0.011251 9.38 83.54 52.09 0.9

Fairview Creek LOMR Page 3 of 8 River: Fairview Creek HEC-RAS Plan: Existing Standard Table 1

Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) Fairview-Halsey 7715 10-YR 257 144.72 149.17 147.44 149.25 0.000836 2.72 151.22 123.72 0.25 Fairview-Halsey 7715 50-YR 346 144.72 150.07 148.01 150.11 0.000366 2.09 272.91 158.98 0.17 Fairview-Halsey 7715 100-YR 369 144.72 150.09 148.31 150.14 0.000407 2.21 276.79 162.35 0.18 Fairview-Halsey 7715 500-YR 490 144.72 150.18 148.84 150.25 0.000653 2.84 291.82 174.8 0.23

Fairview-Halsey 7630 10-YR 257 145.24 148.95 147.85 149.14 0.002067 3.88 113.35 115.65 0.39 Fairview-Halsey 7630 50-YR 346 145.24 150.03 148.37 150.07 0.000499 2.32 320.67 264.44 0.2 Fairview-Halsey 7630 100-YR 369 145.24 150.05 148.51 150.1 0.000544 2.43 326.31 266.19 0.21 Fairview-Halsey 7630 500-YR 490 145.24 150.12 149.06 150.19 0.000836 3.05 344.85 271.84 0.26

Fairview-Halsey 7537 10-YR 257 144.61 148.28 147.16 148.84 0.00378 6.02 42.68 16.09 0.57 Fairview-Halsey 7537 50-YR 346 144.61 149.95 147.69 150.02 0.000727 2.56 222.36 334.82 0.21 Fairview-Halsey 7537 100-YR 369 144.61 149.96 147.82 150.04 0.000797 2.69 226.31 339.05 0.22 Fairview-Halsey 7537 500-YR 490 144.61 149.94 149.74 150.09 0.001541 3.73 213.18 331.77 0.3

Fairview-Halsey 7529 Bridge

Fairview-Halsey 7520 10-YR 257 144.64 147.2 147.2 148.39 0.013496 8.76 29.33 21.16 1 Fairview-Halsey 7520 50-YR 346 144.64 147.73 147.73 149.17 0.012463 9.64 35.9 22.78 1 Fairview-Halsey 7520 100-YR 369 144.64 147.86 147.86 149.36 0.01229 9.85 37.47 23.16 1 Fairview-Halsey 7520 500-YR 490 144.64 149.46 149.46 149.58 0.001292 3.29 233.13 354.21 0.3

Fairview-Halsey 7452.33* 10-YR 257 142.04 144.48 144.48 145.35 0.01629 7.48 34.34 19.88 1 Fairview-Halsey 7452.33* 50-YR 346 142.04 144.9 144.9 145.91 0.015536 8.05 43.01 21.27 1 Fairview-Halsey 7452.33* 100-YR 369 142.04 144.99 144.99 146.04 0.01543 8.2 44.99 21.4 1 Fairview-Halsey 7452.33* 500-YR 490 142.04 145.43 145.43 146.69 0.015181 9 54.43 21.65 1

Fairview-Halsey 7384.67* 10-YR 257 139.45 142.05 142.05 142.99 0.016309 7.79 32.98 17.49 1 Fairview-Halsey 7384.67* 50-YR 346 139.45 142.46 142.46 143.61 0.016114 8.59 40.26 17.66 1 Fairview-Halsey 7384.67* 100-YR 369 139.45 142.57 142.57 143.76 0.015856 8.74 42.24 17.7 1 Fairview-Halsey 7384.67* 500-YR 490 139.45 143.25 143.07 144.52 0.013294 9.04 54.19 17.94 0.92

Fairview-Halsey 7317 10-YR 257 136.85 141.07 139.78 141.51 0.004605 5.32 48.35 14.08 0.51 Fairview-Halsey 7317 50-YR 346 136.85 141.84 140.27 142.37 0.004685 5.83 59.32 14.29 0.5 Fairview-Halsey 7317 100-YR 369 136.85 142.03 140.39 142.58 0.004703 5.95 62.03 14.34 0.5 Fairview-Halsey 7317 500-YR 490 136.85 143.09 140.99 143.72 0.004367 6.34 77.35 14.89 0.48

Fairview-Halsey 7302 Bridge

Fairview Creek LOMR Page 4 of 8 River: Fairview Creek HEC-RAS Plan: Existing Standard Table 1

Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) Fairview-Halsey 7287 10-YR 257 136.64 139.01 139.01 140.14 0.013545 8.52 30.17 14.26 1 Fairview-Halsey 7287 50-YR 346 136.64 139.51 139.51 140.89 0.012693 9.41 36.77 14.4 1 Fairview-Halsey 7287 100-YR 369 136.64 139.62 139.62 141.07 0.012599 9.63 38.31 14.43 1 Fairview-Halsey 7287 500-YR 490 136.64 140.22 140.22 141.97 0.011829 10.59 46.28 14.59 1

Fairview-Halsey 7246.50* 10-YR 257 133.78 136.22 136.22 137.01 0.015987 7.15 35.92 22.59 1 Fairview-Halsey 7246.50* 50-YR 346 133.78 136.6 136.6 137.52 0.015223 7.71 44.88 24.19 1 Fairview-Halsey 7246.50* 100-YR 369 133.78 136.69 136.69 137.65 0.0152 7.86 46.97 24.55 1 Fairview-Halsey 7246.50* 500-YR 490 133.78 137.12 137.12 138.23 0.014691 8.45 57.99 26.36 1

Fairview-Halsey 7206 10-YR 257 130.92 133.17 133.05 133.76 0.014023 6.14 41.89 28.83 0.9 Fairview-Halsey 7206 50-YR 346 130.92 133.53 133.4 134.2 0.014015 6.55 52.83 31.87 0.9 Fairview-Halsey 7206 100-YR 369 130.92 133.62 133.47 134.3 0.014014 6.64 55.58 32.59 0.9 Fairview-Halsey 7206 500-YR 490 130.92 134.03 133.86 134.8 0.014009 7.04 69.58 36.02 0.89

Fairview Creek LOMR Page 5 of 8 River: Fairview Creek HEC-RAS Plans: Existing and Existing-Floodway Standard Table 1

Reach River Sta Profile Plan Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) Fairview 9246 100-YR Existing 354 158.46 162.03 162.03 163.12 0.011612 9.54 59.11 42.38 0.93 Fairview 9246 100-YR Existing-Floodway 354 158.46 162.97 162.44 164.37 0.008411 9.62 42.11 10.53 0.83

Fairview 9145 100-YR Existing 354 157.88 161.48 160.98 161.7 0.003968 5.49 177.27 159.06 0.54 Fairview 9145 100-YR Existing-Floodway 354 157.88 161.89 161.66 163.25 0.014804 9.83 42.97 13.19 0.91

Barr Bypass 186 100-YR Existing 51.21 158 160.25 158.34 160.46 0.009153 3.68 13.9 28.16 0.58 Barr Bypass 186 100-YR Existing-Floodway 52.6 158 160.27 158.34 160.49 0.009117 3.72 14.14 28.3 0.58

Barr Bypass 185 Inl Struct

Barr Bypass 123 100-YR Existing 51.21 157.36 159.02 158.22 159.09 0.002957 2.04 25.14 20.28 0.32 Barr Bypass 123 100-YR Existing-Floodway 52.6 157.36 159.04 158.24 159.11 0.002978 2.06 25.55 20.4 0.32

Barr Bypass 82 100-YR Existing 51.21 156.86 158.25 158.25 158.69 0.033008 5.31 9.65 11.13 1.01 Barr Bypass 82 100-YR Existing-Floodway 52.6 156.86 158.28 158.28 158.71 0.032012 5.29 9.94 11.25 0.99

Barr Bypass 31 100-YR Existing 51.21 155.61 157.85 156.88 157.93 0.002926 2.26 22.63 14.89 0.32 Barr Bypass 31 100-YR Existing-Floodway 52.6 155.61 157.85 156.89 157.94 0.003108 2.33 22.57 14.88 0.33

Fairview-Barr 9007 100-YR Existing 303.79 155.94 159.25 159.25 160.46 0.014406 8.9 35.72 18.02 0.97 Fairview-Barr 9007 100-YR Existing-Floodway 302.4 155.94 159.22 159.2 160.49 0.016891 9.02 33.52 12.83 0.98

Fairview-Barr 8955.50* 100-YR Existing 303.79 154.92 158.62 158.48 159.66 0.013296 8.17 37.22 15.56 0.92 Fairview-Barr 8955.50* 100-YR Existing-Floodway 302.4 154.92 158.61 158.47 159.65 0.013336 8.16 37.07 15.51 0.92

Fairview-Barr 8904 100-YR Existing 303.79 153.89 158.37 157.66 159.05 0.007492 6.57 46.24 16.72 0.7 Fairview-Barr 8904 100-YR Existing-Floodway 302.4 153.89 158.36 157.65 159.03 0.007507 6.57 46.04 16.69 0.7

Fairview-Barr 8883 Bridge

Fairview-Barr 8861 100-YR Existing 303.79 153.95 156.95 156.95 157.97 0.015437 8.12 37.39 18.11 1 Fairview-Barr 8861 100-YR Existing-Floodway 302.4 153.95 156.93 156.93 157.96 0.015641 8.15 37.1 18.06 1

Fairview-Halsey 8843 100-YR Existing 355 152.67 156.64 156.17 157.64 0.007618 8.61 51.09 33.31 0.78 Fairview-Halsey 8843 100-YR Existing-Floodway 355 152.67 156.64 156.17 157.64 0.007618 8.61 51.09 33.31 0.78

Fairview-Halsey 8755 Bridge

Fairview Creek LOMR Page 6 of 8 River: Fairview Creek HEC-RAS Plans: Existing and Existing-Floodway Standard Table 1

Reach River Sta Profile Plan Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) Fairview-Halsey 8666 100-YR Existing 355 150.88 154.1 153.85 155.01 0.009546 7.75 49.62 23.76 0.83 Fairview-Halsey 8666 100-YR Existing-Floodway 355 150.88 154.4 153.82 155.19 0.008748 7.11 49.93 16.6 0.72

Fairview-Halsey 8572.50* 100-YR Existing 355 149.93 153.46 152.91 154.18 0.006592 6.92 56.38 24.43 0.7 Fairview-Halsey 8572.50* 100-YR Existing-Floodway 355 149.93 154.08 152.91 154.55 0.003408 5.64 72.41 27.39 0.52

Fairview-Halsey 8479 100-YR Existing 364 148.99 153.08 152.07 153.61 0.004052 6 69.31 26.74 0.57 Fairview-Halsey 8479 100-YR Existing-Floodway 364 148.99 153.78 152.04 154.2 0.00352 5.22 69.74 16.6 0.45

Fairview-Halsey 8429 100-YR Existing 364 148.11 152.92 151.64 153.42 0.003286 5.87 74.59 27.37 0.51 Fairview-Halsey 8429 100-YR Existing-Floodway 364 148.11 153.63 151.59 154.05 0.002667 5.22 73.68 16.13 0.42

Fairview-Halsey 8377 Bridge

Fairview-Halsey 8324 100-YR Existing 364 147.52 152.49 150.58 152.8 0.001861 4.59 94.37 31.53 0.39 Fairview-Halsey 8324 100-YR Existing-Floodway 364 147.52 153.44 150.54 153.69 0.001639 4.01 90.88 17.14 0.31

Fairview-Halsey 8184 100-YR Existing 364 147.19 151.9 151 152.38 0.003818 6.03 81.95 34.81 0.55 Fairview-Halsey 8184 100-YR Existing-Floodway 364 147.19 152.69 150.96 153.24 0.004617 5.95 61.19 13.4 0.49

Fairview-Halsey 8044 100-YR Existing 369 147.46 151.46 150.5 151.87 0.003271 5.4 92.68 54.86 0.51 Fairview-Halsey 8044 100-YR Existing-Floodway 369 147.46 152.3 150.39 152.68 0.002932 4.93 74.85 17.28 0.42

Fairview-Halsey 7946 100-YR Existing 369 147.69 151.16 150.3 151.52 0.003498 5.13 99.32 63.65 0.52 Fairview-Halsey 7946 100-YR Existing-Floodway 369 147.69 152.1 150.21 152.4 0.002357 4.38 84.32 21.07 0.39

Fairview-Halsey 7859 100-YR Existing 369 145.66 150.66 149.69 151.02 0.002913 5.34 115.01 152.81 0.46 Fairview-Halsey 7859 100-YR Existing-Floodway 369 145.66 151.34 149.46 151.88 0.004387 5.87 62.85 13.14 0.47

Fairview-Halsey 7788 100-YR Existing 369 145.99 149.68 149.68 150.61 0.01042 8.36 65.76 44.69 0.85 Fairview-Halsey 7788 100-YR Existing-Floodway 369 145.99 150.3 149.7 151.36 0.010873 8.24 44.78 12.26 0.76

Fairview-Halsey 7715 100-YR Existing 369 144.72 150.09 148.31 150.14 0.000407 2.21 276.79 162.35 0.18 Fairview-Halsey 7715 100-YR Existing-Floodway 369 144.72 150.6 147.96 150.86 0.001747 4.11 89.7 17.95 0.32

Fairview-Halsey 7630 100-YR Existing 369 145.24 150.05 148.51 150.1 0.000544 2.43 326.31 266.19 0.21 Fairview-Halsey 7630 100-YR Existing-Floodway 369 145.24 150.29 147.57 150.66 0.002877 4.92 74.98 16.81 0.41

Fairview-Halsey 7537 100-YR Existing 369 144.61 149.96 147.82 150.04 0.000797 2.69 226.31 339.05 0.22 Fairview-Halsey 7537 100-YR Existing-Floodway 369 144.61 150.13 147.83 150.41 0.002015 4.31 91.45 33.98 0.35

Fairview-Halsey 7529 Bridge

Fairview Creek LOMR Page 7 of 8 River: Fairview Creek HEC-RAS Plans: Existing and Existing-Floodway Standard Table 1

Reach River Sta Profile Plan Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) Fairview-Halsey 7520 100-YR Existing 369 144.64 147.86 147.86 149.36 0.01229 9.85 37.47 23.16 1 Fairview-Halsey 7520 100-YR Existing-Floodway 369 144.64 147.86 147.86 149.36 0.012291 9.85 37.47 23.16 1

Fairview-Halsey 7452.33* 100-YR Existing 369 142.04 144.99 144.99 146.04 0.01543 8.2 44.99 21.4 1 Fairview-Halsey 7452.33* 100-YR Existing-Floodway 369 142.04 144.99 144.99 146.04 0.01543 8.2 44.99 21.4 1

Fairview-Halsey 7384.67* 100-YR Existing 369 139.45 142.57 142.57 143.76 0.015856 8.74 42.24 17.7 1 Fairview-Halsey 7384.67* 100-YR Existing-Floodway 369 139.45 142.57 142.57 143.76 0.015858 8.74 42.24 17.7 1

Fairview-Halsey 7317 100-YR Existing 369 136.85 142.03 140.39 142.58 0.004703 5.95 62.03 14.34 0.5 Fairview-Halsey 7317 100-YR Existing-Floodway 369 136.85 142.03 140.39 142.58 0.004703 5.95 62.03 14.34 0.5

Fairview-Halsey 7302 Bridge

Fairview-Halsey 7287 100-YR Existing 369 136.64 139.62 139.62 141.07 0.012599 9.63 38.31 14.43 1 Fairview-Halsey 7287 100-YR Existing-Floodway 369 136.64 139.62 139.62 141.07 0.012599 9.63 38.31 14.43 1

Fairview-Halsey 7246.50* 100-YR Existing 369 133.78 136.69 136.69 137.65 0.0152 7.86 46.97 24.55 1 Fairview-Halsey 7246.50* 100-YR Existing-Floodway 369 133.78 136.69 136.69 137.65 0.0152 7.86 46.97 24.55 1

Fairview-Halsey 7206 100-YR Existing 369 130.92 133.62 133.47 134.3 0.014014 6.64 55.58 32.59 0.9 Fairview-Halsey 7206 100-YR Existing-Floodway 369 130.92 133.62 133.47 134.3 0.014014 6.64 55.58 32.59 0.9

Fairview Creek LOMR Page 8 of 8

1) Existing 2/24/2020 FAIRVIEW CREEK Fairview-Halsey F F 165 A A I I Legend R R V V WS 500-YR I I E E WS 100-YR W W WS 50-YR C C 160 R R WS 10-YR E E E E Ground K K

F F a a i i r r 155 v v i i e e w w - B a r r 150 Elevation Elevation (ft)

145

140

135 SE Matney St Ln Walnut NE Fairview Ave / Ave NE 223rd NE Halsey St Rd Barr 130 0 500 1000 1500 2000 2500 Main Channel Distance (ft)

1) Existing 2/24/2020 FAIRVIEW CREEK Fairview-Halsey F F 165 A A I I Legend R R V V WS 500-YR I I E E WS 100-YR W W WS 50-YR C C 160 R R WS 10-YR E E E E Ground K K

B F a a r i r r 155 v B i y e p w a s s

150 Elevation Elevation (ft)

145

140

135 SE Matney St Ln Walnut NE Fairview Ave / Ave NE 223rd NE Halsey St Concrete weir with installed 2-ft flashboards 130 0 500 1000 1500 2000 2500 Main Channel Distance (ft) Fairview Creek Letter of Map Revision Field Photographs

Barr Rd Bypass Weir—Looking upstream towards Fairview Creek

Fairview Avenue—Looking upstream of culvert inlet Fairview Creek Letter of Map Revision Field Photographs

Fairview Avenue—Looking at floodplain downstream of culvert outlet

Walnut Lane—Looking at channel and floodplain upstream of bridge Fairview Creek Letter of Map Revision Field Photographs

Walnut Lane—Looking at channel and floodplain downstream of bridge

Matney Street—Looking at channel and floodplain upstream of bridge Fairview Creek Letter of Map Revision Field Photographs

Matney Street—Looking at channel and floodplain downstream of bridge