Hydraulic Report. County Road 595 Bridge over Second River. Prepared By AECOM Brian A. Hintsala, P.E

Transcription

1 Prepared for: Prepared by: Marquette County Road Commission AECOM Ishpeming, MI Marquette, MI December 9, 2011 Hydraulic Report County Road 595 Bridge over Second River Prepared By AECOM Brian A. Hintsala, P.E

2 AECOM i Contents 1.0 Introduction Method of Analysis Variables and Coefficients Starting Point Discussion Conclusion... 2 List of Appendices Appendix A HEC-RAS Computations Appendix B Profile Sheets Appendix C Topographic Map HEC-RAS River Sections Appendix D Bridge Plans Appendix E Cross Sections Appendix F Damage Waivers Appendix G Flow Rates Appendix H Site Photographs Appendix I USGS Topographical Map and River Gradient Calculations

3 AECOM Introduction This hydraulic report is being prepared for the Marquette County Road Commission concerning the proposed County Road 595 crossing of the Second River. The site is located in Section 25 of T48N, R29W, Quad Map Name - Diorite (Lat /Long ) in Champion Township, Marquette County. Multiple road alignments were investigated. The chosen alignment crosses the river at the site of an existing crossing composed of multiple culverts. The existing culverts are both structurally and geometrically inadequate for the projected road traffic and require replacement. 2.0 Method of Analysis The hydraulic analysis was performed using the HEC-RAS River Analysis System computer program, Version developed by the U.S. Army Corps of Engineers Hydraulic Engineering Center. The steady flow data for the flood events were obtained from the Michigan Department of Environmental Quality (MDEQ). 3.0 Variables and Coefficients The river sections near the bridge use an expansion coefficient of 0.30 and contraction coefficient of 0.50 which are suitable for a typical bridge per Table 3.3 of the HEC-RAS Hydraulic Reference Manual. The Manning s n-values for friction loss were selected using Table 3.1 of the HEC-RAS Hydraulic Reference Manual. The main channel is fairly uniform with some weeds so a value of was chosen. The overbanks are covered with medium brush so a value of was chosen. Representative photographs of the site are included in Appendix H. 4.0 Starting Point The starting point of the analysis was a surveyed river section about 227 feet downstream of the proposed road. This location was chosen because it was far enough downstream to be outside of the influence of the proposed bridge. The starting water surface elevation was calculated by HEC-RAS using the slope-conveyance method. An average channel slope of was estimated from a USGS quadrangle map and used for the normal depth boundary condition. The calculations are included in Appendix I. 5.0 Discussion The main channel of the Second River is variable in width and not well defined. At the 100-year flood event a large portion of the flow is carried by the overbank floodplain. The river gradient is relatively flat and the flow regime is sub-critical for all flood events. The existing crossing is composed of two 36" circular culverts and one 42" x 66" elliptical culvert. Because of the relatively low hydraulic capacity of the existing culverts, the road is overtopped during flood events. The proposed bridge will be placed directly over the location of the existing culverts. The proposed bridge has a span of 58 feet. The relatively large span is required to replace the culverts because the overtopping of the existing road during flood events. In addition, the proposed

4 AECOM 2 bridge is highly skewed (to align it to the river channel) which reduces its effective width. The proposed bridge is composed of a prestressed concrete box beam deck supported by concrete foundation walls on steel piles. The restored stream banks are protected with heavy riprap. The proposed bridge has a large enough hydraulic opening to reduce the water elevations upstream of the bridge without overtopping the proposed road. The river cross sections are placed in HEC-RAS at the distances measured along the center line of the channel. In some cases the surveyed sections on each side of the bridge were adjusted up or downstream as required to model the bridge using the standard bridge/culvert input section of HEC- RAS. This is required because the actual location of the bridge was not known when the survey was performed. The final positions of the sections are shown in the plan view in Appendix C. The existing road approaches cut off a portion of the overbank flow during the higher flow events. Ineffective flow areas were included in the overbank portions of the cross sections upstream and downstream of the bridge as suggested in chapter 5 of the HEC-RAS Hydraulic Reference Manual. The proposed bridge has a larger hydraulic opening than the existing culverts. This reduces the water velocity at the crossing as well as the water elevation upstream. Table 1 on the following page summarizes the key model results for two configurations: 1. The existing 3 culvert crossing. 2. The proposed 58 span bridge. 6.0 Conclusion Analysis results indicate that the proposed bridge decreases water surface elevations and channel velocities for all of the flow events compared to the existing bridge.

5 Hydraulic Comparison of Bridge Options County Road 595 over Second River 3/18/2011 Table 1 HEC-RAS Analysis Results Velocity in Channel at Bridge River Station 8.5 Flow thru Bridge Opening Water Surface Elevation at Upstream Face of Bridge River Station 9 Energy Gradient Elev at Upstream Face of Bridge River Station 9 Energy Gradient Elevation at 450' Upstream of Bridge River Station 11 (ft/sec) (cfs) (feet) (feet) (feet) Model Configuration 100 Year 10 Year 100 Year 100 Year 100 Year 100 Year (600 cfs) (220 cfs) (600 cfs) (600 cfs) Change (600 cfs) Change (600 cfs) Change Existing Culverts Proposed Bridge

6 AECOM Appendix A HEC-RAS Computations

7 AECOM Computations The HEC-RAS data files are included in a separate electronic folder named: HEC-RAS_CR 595 over Second River.zip In order to provide a brief summary of the analysis results, a Profile Output Table for both the existing and proposed conditions are included on the following pages.

8 HEC-RAS Plan: Ex Culverts River: Second Riv Reach: Main 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 Culv Vel DS Culv Vel US Q Culv Group Q Weir (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) (ft/s) (ft/s) (cfs) (cfs) Main 11 Q Main 11 Q Main 11 Q Main 10 Q Main 10 Q Main 10 Q Main 9 Q Main 9 Q Main 9 Q Main 8.5 Culvert #2 Q Main 8.5 Culvert #1 Q Main 8.5 Culvert #3 Q Main 8.5 Culvert #2 Q Main 8.5 Culvert #1 Q Main 8.5 Culvert #3 Q Main 8.5 Culvert #2 Q Main 8.5 Culvert #1 Q Main 8.5 Culvert #3 Q Main 8 Q Main 8 Q Main 8 Q Main 7 Q Main 7 Q Main 7 Q

9 HEC-RAS Plan: New Bridge River: Second Riv Reach: Main 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 Culv Vel DS Culv Vel US Q Culv Group Q Weir (cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) (ft/s) (ft/s) (cfs) (cfs) Main 11 Q Main 11 Q Main 11 Q Main 10 Q Main 10 Q Main 10 Q Main 9 Q Main 9 Q Main 9 Q Main 8.5 BR U Q Main 8.5 BR U Q Main 8.5 BR U Q Main 8.5 BR D Q Main 8.5 BR D Q Main 8.5 BR D Q Main 8 Q Main 8 Q Main 8 Q Main 7 Q Main 7 Q Main 7 Q

10 AECOM Appendix B Profile Sheets

11 Wolf Lake Road over Second River Plan: Existing culverts 3/18/2011 Second Riv Main Legend EG Q100 WS Q100 EG Q50 WS Q50 Crit Q100 EG Q10 WS Q10 Crit Q50 Crit Q10 Ground Elevation (ft) Main Channel Distance (ft)

12 Wolf Lake Road over Second River Plan: New Bridge 3/18/2011 Second Riv Main Legend EG Q100 WS Q100 EG Q50 WS Q50 Crit Q100 EG Q10 WS Q10 Crit Q50 Crit Q10 Ground 1558 Elevation (ft) Main Channel Distance (ft)

13 AECOM Appendix C Topographic Map HEC-RAS River Sections

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15 AECOM Appendix D Bridge Plans

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19 AECOM Appendix E Cross Sections

20 AECOM Cross Section Cross sections are included for the existing condition and the proposed bridge condition.

21 AECOM Existing Channel Condition

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28 AECOM Proposed Bridge Condition

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35 AECOM Appendix F Damage Waivers

36 AECOM No Damage Waivers Required

37 AECOM Appendix G Flow Rates

38 DEQ - Flood Frequency Discharges Page 1 of 1 12/6/2011 Joint Permit Application DEQ Home CIWPIS Online Services Permits Programs Site Map Contact DEQ Flood Discharge Request Record /6/2011 Home Water Management Lowflows Discharge Requests Watersheds Map Discharge Information Watercourse: SECOND RIVER Location: Wolf Lake Road Drainage Area: 6.52 mi 2 Basin Name: 46 - Escanaba Contributing Area: 6.52 mi 2 County: Marquette Tn/Rng/Sec: 48N29W/25 Township: Champion Latitude: Quad Name: Champion Longitude: Quad ID: D11SW Requested By: Sheila Meier (DEQ-LWM- Received Date: 11/23/2011 Ishpeming) Request Type: Trans. - County Issued Date: 12/5/2011 File Number: Reference Number: Discharge Frequencies: Volume Frequencies: 10%: 220 cfs 2%: 460 cfs 1%: 600 cfs 1%: 750 acre-ft 0.5%: 800 cfs 0.5%: 900 acre-ft 0.2%: 1100 cfs Access to the Flood Flow Database is provided as a service to allow you to check the status of your flood flow requests or to view discharges from previous requests for preliminary design purposes. The discharges values are only valid for the original requestor and for one year after the original request date. To obtain discharge information from the Hydrologic Studies Program, a flood flow discharge request form may be submitted electronically to the DEQ. A written or response to your request will be returned to you and must accompany your permit application. Michigan.gov Home DEQ_Home Online Services Permits Programs Site Map Contact_DEQ State Web Sites Privacy Policy Link Policy Accessibility Policy Security Policy Copyright 2011 State of Michigan

39 AECOM Appendix H Photos

40 County Road 595 over Second River Existing Crossing Looking North Downstream End of Culverts

41 County Road 595 over Second River Looking Downstream from Existing Crossing Upstream End of Culverts

42 County Road 595 over Second River Looking Upstream from Existing Crossing

43 AECOM Appendix I USGS Topographical Map and River Gradient Calculations Map includes portions of Quadrangle maps: Champion Republic Diorite Greenwood

44 087 54' 0.00" W ' 0.00" W ' 0.00" W ' 0.00" N ' 0.00" N ' 0.00" N ' 0.00" N ' 0.00" N ' 0.00" N CR 595/Second Riv 20' Intv mi 20' diff = 20'/16,452'= or 0.12% W ' 0.00" W ' 0.00" W Copyright (C) 1999, Maptech, Inc ' 0.00" W