Van_Duzen_CA_sr36(1)_Final_Hydraulic_Report__December_2014.pdf

Final Hydraulic Report

Van Duzen – Peanut Road

CA SR 36 (13)

Prepared by Veronica Ghelardi

Technical Services Hydraulic Engineer Central Federal lands Highway Division

Lakewood, Colorado December, 2014

TABLE of CONTENTS

INTRODUCTION

PROJECT BACKGROUND AND OBJECTIVES

ROADWAY HYDRAULIC DESIGN STANDARDS

VAN DUZEN FLOODPLAIN ANALYSIS

Federal Emergency Management Agency (FEMA) Floodplain Mapping

Hydrology

Hydraulic Analysis

Existing Conditions

Proposed Conditions

CULVERTS

Proposed Culvert Hydrology and Sizing

Burr Creek

SUMMARY

Floodplain/Roadway

Culverts

REFERENCES

APPENDIX A

APPENDIX B

Figures Figure 1. Project Site Location Map Figure 2. Boundaries of the California Flood-Frequency Regions and Regression Equations Figure 3. Existing Water Surface Elevation at Road Overtopping Location Figure 4 Water Surface Elevation at River Station 1703 (Proposed MP 2090+00)

Tables Table 1. Hydraulic Standards Table 2. Van Duzen Bridge Basin characteristics Table 3. Regional Flood Frequency Equations for North Coast Region - California Table 4. USGS Regression Equation Calculated Bridge Discharges Table 5. HEC RAS Existing Bridge Water Surface Elevations Table 6. Difference in Water Surface Elevations between Existing and Proposed Conditions Table 7. Proposed Stream Crossing Culvert Locations, Discharges and Sizes Table 8 Burr Creek Culvert Options file://///169.135.233.27/projects/CA/sr36(13)/Hydraulics/9_Final-Report/Van%20Duzen%20CA%20sr36(1)_Final%20Hydraulic%20Report%20_June%202014.docx%23_Toc389556792

INTRODUCTION

The purpose of this report is to provide: 1) hydrologic analysis for the bridge on the northern end of the project, 2) the effects of the proposed road re-alignment on the existing floodplain limits, and 3) recommendations of the proposed stream culvert sizes.

PROJECT BACKGROUND AND OBJECTIVES

The project is located on State Road 36 Humboldt County project in, Humboldt County California. The road provides access between California’s coast and interior by providing an important road link between U.S. 101 and Interstate 5. Figure 1.

The existing roadway is heavily used by tourists and commuters, even though there are sections of the road that operate at 12 mph. The main purpose of the project is to upgrade the operating speed along the 4.4 miles of the project by re-aligning the roadway.

ROADWAY HYDRAULIC DESIGN STANDARDS

The Central Federal Land’s Project Development Design Manual (PDDM) considers a highway a high-standard road if the Average Daily Traffic (ADT) is => 1500 vehicles /day. Since the ADT on SR 36 is more than 1500 vehicles/day, it is considered a high standard road. In addition the requirements of the Regional Water Quality Control Board’s (RWQCB) hydraulic standards (culverts should be designed to be 2/3 full for the 100-yr flood event) were used for all cross culverts on this project except for the Burr Creek culvert. The CALTRANS Regional Hydraulics Engineer stated that CALTRANS would not typically use the Water Board requirements for culverts to be 2/3 full for the 100-yr event. CALTRANS standard is

Figure 1. Project Site Location Map to design the culverts so that the road is not overtopped by the 100-yr flood event. It was decided by the cross functional team that the cross culverts would still be designed to the Water Board’s standard so that the road would not be flooded in extreme weather events. The only exception to the Water Board’s standard is the Burr Creek culvert. The existing Burr Creek culvert is 8 ft in diameter. To design a culvert at this site to be only 2/3 full for the 100-yr flood event would be too costly. Therefore, this culvert was designed to the CFL standard of a headwater to diameter ratio(HW/D), which for culverts larger than 48 inches is equal to 1.2. Table 1 shows the standards used in the design of the culverts and ditches.

Feature Capacity Design Stability Design Scour Check Flood

Bridge 50-yr flood event 100-yr 200-yr

Cross Culverts 100-yr (flowing 2/3 full) NA NA

Burr Creek Culvert 100-yr event (HW/D = <1.2)

NA NA

Roadside Ditch 10-yr 10-yr NA

Table 1. Hydraulic Standards

VAN DUZEN FLOODPLAIN ANALYSIS

Federal Emergency Management Agency (FEMA) Floodplain Mapping

A search for the FEMA Flood Insurance Rate map (FIRM) found that the study area of the Van Duzen River is defined as a Zone A. FEMA Zone A maps only estimate the limits of the base floodplain (100-yr flood). No engineering studies were conducted and no base flood elevations were determined by FEMA.

To determine any impacts of the proposed conditions, an existing-conditions hydraulic model must be developed and compared to the proposed conditions model. If there is more than a one foot increase in the base flood elevations between the existing and proposed conditions models, a Conditional Letter of Map Revision (CLOMR) must be submitted to FEMA. Once the CLOMR is approved by FEMA, the project may be constructed and a Letter of Map Revision (LOMR) would then be submitted to FEMA within 60 days of the end of construction.

Since the bridge will not be replaced, the purpose of the hydraulic analysis is to define the downstream floodplain water surface elevations that currently exist and determine if the current road alignment is overtopped. The intent of this analysis is to confirm a less than 1 foot rise in the 100-year water surface levels due to any road re-alignment and to ensure that the proposed new road realignment does not negatively impact the floodplain.

Hydrology

The USGS StreamStats website was used to obtain the drainage area and basin characteristics including the mean annual precipitation. The site also was used to obtain the updated USGS regression equations for the North Coast Region of California (Figure 2) to compute the 2-, 5-, 10-, 25-, 50-, 100-, and 500-year peak discharge estimates . Table 2 shows the drainage area calculated for the bridge at the north end of the project and the mean annual precipitation:

Drainage Area (square miles)

80.6

Mean Annual

Precipitation (inches)

74.2

Table 2. Van Duzen Bridge Basin characteristics

Figure 2. Boundaries of the California Flood-Frequency Regions and Regression Equations

Table 3 shows the 2012 USGS regression equations for the North Coast Region of California used to calculate the peak discharge at the bridge location. Table 4 shows the results of the calculated discharges for the various return periods based on those equations.

Van Duzen Bridge

Table 3. Regional Flood Frequency Equations for North Coast Region - California

Return Period Discharge (cfs)

2-yr 6640

5-yr 11100

10-yr 14100

25-yr 18019

50-yr 20900

100-yr 23800

500-yr 26500

Table 4. USGS Regression Equation Calculated Bridge Discharges

Hydraulic Analysis

Existing Conditions

Reports from the FHWA Northern California Resident Engineer indicate that approximately 2000 feet downstream of the Van Duzen bridge across the Van Duzen River, the road is overtopped during large storm events. A bridge hydrologic and hydraulic analysis were performed to determine any effects the bridge might have on the downstream water surface elevations and to determine where the roadway is overtopped.

The U.S. Army Corps of Engineers (USACE) Hydrologic Engineering Center River Analysis System (HEC- RAS) version 4.1, 2010 software was used to analyze the existing hydraulic conditions and to determine the existing floodplain boundaries. Cross sections for the hydraulic model were cut from LIDAR elevation data in the MicroStation project file. The hydraulic model extended upstream from the existing bridge 1150 feet and downstream from the bridge approximately 2555 feet. The bridge configuration was based on “as-built” drawings obtained from CALTRANS.

It has been reported that an area of the roadway approximately 2000 feet downstream of the existing bridge has experienced flooding after major storms. The existing HEC RAS model did show that the 100-year flood event overtopped the road in the area of concern, Figure 3.

Figure 3. Existing Water Surface Elevation at Road Overtopping Location

Table 5 shows the existing 100-year water surface elevations. The road is overtopped between hydraulic cross sections 1325 and 1703 by approximately 2 feet of water with the low point elevation of the road being 2355 feet on the streamside road edge.

100-yr WSEL 2356.62

Road Location

Elevation?

Proposed Conditions

The re-alignment of SR 36 was analyzed to determine if the re-alignment would cause a water surface elevation rise in the floodplain downstream of the bridge in the area where overtopping of the road currently occurs during major storm events. The proposed HEC RAS model was based on the existing HEC RAS model. The re-alignment affected river cross sections 1325, 1703, 2192, 2491, 2810, 3008, 3292, 2435, 3697, and 3816 so these cross sections were modified to reflect the new road alignment.

The proposed model showed that the new alignment caused a less than 1 foot rise in the 100-year water surface elevation and that the proposed roadway is not overtopped between river cross sections 1325

Q Total (cfs)

River Station

Water Surface Elev. (ft)

23800 5076 2373.53

23800 4854 2373.28

23800 4635 2367.79

23800 4365 2368.90

23800 4067 2367.44

23800 4013 2367.77

Bridge 4000

23800 3965 2366.09

23800 3915 2362.97

23800 3816 2362.29

23800 3697 2362.40

23800 3435 2361.11

23800 3292 2361.89

23800 3008 2360.64

23800 2810 2359.95

23800 2491 2359.32

23800 2192 2358.32

23800 1703 2356.62

23800 1325 2351.80

23800 1101 2350.52

Table 5. HEC RAS Existing Bridge Water Surface Elevations and 1703 (Proposed MP 2090+00). The biggest rise of 0.09 ft. occurred at river cross section 2491. See Table 7.

Figure 4 Water Surface Elevation at River Station 1703 (Proposed MP 2090+00)

River Station

Existing Water

Surface Elevation

(ft)

Proposed Re-

Alignment Water

Surface Elevation

(ft)

Difference in

Water Surface

Elevations (ft)

Proposed

Roadway

Elevation (ft)

5076 2373.53 2373.53 0

4854 2373.28 2373.28 0

4635 2367.79 2367.79 0

4365 2368.90 2368.90 0

4067 2367.44 2367.44 0

4013 2367.77 2367.77 0

Bridge

Roadway

100-yr Water Surface Elevation

3965 2366.09 2366.09 0

3915 2362.97 2362.97 0

3816 2362.29 2362.30 0.01

3697 2362.40 2362.41 0.01

3435 2361.11 2361.13 0.02

3292 2361.89 2361.91 0.02

3008 2360.64 2360.66 0.02

2810 2359.95 2359.97 0.02

2491 2359.39 2359.48 0.09

2192 2358.32 2358.36 0.04

1703 2356.62 2356.69 0.07 2360

1325 2351.80 2351.80 0 2365

1101 2350.52 2350.52 0

Table 6. Difference in Water Surface Elevations between Existing and Proposed Conditions

CULVERTS

Proposed Culvert Hydrology and Sizing

The proposed road alignment, contours and roadway stationing (Microstation dgn file) were saved as a dwg and imported into WMS. This file was then merged with the existing Digital Elevation Model (DEM) file in WMS. From this merged elevation file the flow accumulation routine was run to determine where concentrated channel flow would occur with a drainage area of at least 0.5 acre. Outlets were placed where the flow accumulation intersected the new road profile and the drainage area of each outlet was calculated by WMS.

The outlets/stream crossings discharges were determined by the Rational Method for all drainage areas less than 200 acres using the FHWA Hydraulic Toolbox. Only one drainage area, Burr Creek (MP 1970+16), was larger than 200 acres and the North Coast Regression equation was used to determine the discharge for this drainage area. The FHWA HY-8 culvert sizing program was used to size all culverts.

The results are summarized in Table 6 below.

The dwg and DEM files did not provide a smooth transition between the elevation files so the inlet and outlet invert elevations were determined from the original Microstation dgn file of the proposed alignment and contours. This file did not extend far enough in some cases to determine the correct inlet invert elevation so the most reasonable elevation was used from the proposed contour files. In most cases this resulted in the roadway profile being too low to accommodate the culverts.

Update: during the 70% site visit all proposed culvert locations were scouted to check whether culverts were needed in every culvert location. Several culvert locations revealed that there was no concentration of flow so these culverts were deleted from the list. Table 7 shows the updated stream culvert stations, drainage areas, and sizes for the 100-year design event (except the Burr Creek 10 ft.

CMP pipe which is designed for the 50-year event.

Proposed

Mile Post

DA

(acres)

100-yr

(cfs)

Invert

Elev (ft)

Outlet

Elev

(ft)

HW

Elev

(ft)

HW/D

Culvert size

1905+31 12 11 2581.5 2580 2.13 0.51 36”

1917+31 107 86.5 2636 2625 4.85 1.21 48”

1932+00 147 109 2738 2735 4.8 1.07 54”

1935+39 7 18.3 2809 2763 2.85 0.82 30”

1956+22 6 4.5 2900.5 2873 0.68 0.34 24"

1957+99 11 7.1 2883 2862 1.25 0.63 24"

1959+72 11 6.8 2873 2833 1.48 0.99 18”

1966+66 6 17.1 2821.5 2820 2.23 0.90 30"

1968+81 1076 840 2784 2720 10.92 1.07 10’

CMP

1974+89 13 9.4 2752.2 2690.6 1.45 0.73 24"

1977+13 4 3.3 2740 2700 0.63 0.46 18”

1984+66 25 30 2711 2708 2.88 0.96 36”

1999+06 78 60 2615 2598 4.11 1.17 42”

2001+97 5 6 2572.5 2563 1.5 1.0 18”

2014+36 115 76 2480 2475 2.83 0.44 6x4

2023+46 152 94 2497 2491 3.06 0.77 48"

2048+58 94 48 2534.5 2532 2.46 0.82 36"

2051+60 23 23.8 2524 2508 2.73 1.40 30"

2054+19 13 60 2528 2523 2.92 0.58 60”

2075+23 181 147.8 2442 2437. 5.2 1.04 60"

2087+14 5 6 2357 2355 1.35 0.90 18"

2089+35 53 50.9 2350 2345 3.97 1.33 36”

Table 7. Proposed Stream Crossing Culvert Locations, Discharges and Sizes

All the proposed cross culverts except the Burr Creek culvert, were sized to accommodate the 100-year flood event and remain in the acceptable HW/D ratio of 1.5 for culverts < 48”. The Burr Creek culvert has a HW/D ratio of 1.07 The acceptable ratio for culverts >48” is HW/D = 1.2.

Burr Creek The existing Burr Creek culvert is an 8 foot diameter CMP pipe on an 33% +slope with headwalls , wingwalls and upstream concrete apron on a steep slope to the culvert. Approach flow must make a 90 degree turn to flow into the culvert. Upstream of the culvert the stream descends through a steep ravine with slope stability issues that cause heavy debris to accumulate near the culvert entrance. In addition the road to the right of the culvert (orientation looking downstream) is situated on a slide area;

however, the culvert itself is out of the slide area. Observation of low flow discharges reveal that low flow does not enter the existing culvert inlet. Several feet upstream of the culvert low flows become subsurface. However, at least a portion of this flow is entering somewhere in the middle of the culvert as water can be seen discharging at the outlet. Any new culvert or culvert replacement will need to add a cutoff wall at the culvert inlet to address the piping issue. The water discharging from the culvert outlet has formed a natural stilling basin at the outlet with large rocks surrounding the basin.

Downstream of the stilling basin the channel continues on a more mild slope of 2-4% for about 75 feet with large rocks in the channel. From there the channel continues on a steep gradient.

Several culvert replacement/rehabilitation options were analyzed including structural steel arch plate, CMPs, box culverts and lining the existing culvert. The generic culvert slipliner was assumed to be a slick, plastic liner with a low n value in the 0.01 range. The following culvert options were sized to meet CFL criteria of HW/D =1.2. The results are shown in Table 7.

Pipe Type Dimensions (span x rise)

Outlet Velocity (ft/s)

HW/D Allowable?

Structural Steel Plate Pipe Arch

141.8” 91.3” 35 1.20 Yes

CBC 10’ x 8’ 55 1.18 Yes

CMP 9’ 45 1.20 Yes

CMP 8’ 45 1.75, overtops the road at 898 cfs

No

Snap Tite Liner* 6.5’ Inner Diameter

55 Overtops road at 615 cfs

No

Generic Slip Liner 7.5 ‘ 54 Overtops the road at 799 cfs

No

Generic Slip Liner with 2.5’ overflow pipe

7.5 ‘ 54 1.7 No

* Inner Diameter from Snap Tite Product Specification Table – Appendix C Table 8 Burr Creek Culvert Options The first three options would conform to the CFL standard so the deciding factors may be cost and constructablity.

SUMMARY

Floodplain/Roadway

The 100-yr flood event discharge is 23800 cfs. The existing HEC-RAS model shows that the road is inundated in the area of concern (approximately 1900 feet downstream of the bridge) by approximately 2 feet of water between river stations 1703 and 1325. The proposed HEC RAS model that is based on the proposed road realignment shows no overtopping of the road and only a slight water surface elevation increase of 0.09 ft at river station 2491.

Culverts

The 30 proposed cross drainage culverts were sized for the 100-year flood event and conform to the CFL

HW/D ratio =<1.5 for culverts <48”.

Update – December 2014

In the summer of 2014 a decision was made to remove the Burr Creek 8 ft diameter CMP pipe and replace it with a 10 ft diameter CMP pipe with structural steel plate welded to the bottom of the pipe.

This decision was made in cooperation with senior CALTRANS hydraulic engineers in Sacramento. The steel plate will protect the bottom of the pipe from the large rocks and heavy debris load that must pass through the pipe due to the debris generated by the slide upstream. The Burr Creek culvert conforms to the HW/D ratio of 1.2 for culverts >48” with a HW/D = 1.07.

REFERENCES

Aquaveo (2012) Watershed Modeling System 9.1 (www.aquaveo.com)

FHWA (2007) “Project Development and Design Manual for Central Federal Lands Highway Division” Chp. 7. Federal Highway Administration (FHWA)

FHWA (2012) HY-8 Culvert Analysis Program version 7.3

FHWA Hydraulic Toolbox (2013) version 4.2

Hydrologic Engineering Center River Analysis System (HEC-RAS) Software”, USACE (2010) “US Army Corps of Engineers HydVersion 4.1 build date 2010

National Oceanic Atmospheric Administration (NOAA) Hydrometeorological Design Studies Center, Precipitation Frequency Data Server, NOAA Atlas 14, California

USGS Stream Stats California application accessed September 2012 at http://water.usgs.gov/osw/streamstats/california.html http://www.aquaveo.com/ http://water.usgs.gov/osw/streamstats/california.html

APPENDIX A

HYDROLOGY

StreamStats Drainage Area of Van Duzen Bridge on north side of project.

Discharge Results from USGS North Coast (Region 1) Equations

WMS graphic of culvert drainage areas

APPENDIX B

BRIDGE HYDRAULICS

Location of HEC RAS Bridge Cross Sections

Existing Conditions HEC RAS MODEL

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)

STREAM 5076 2-yr 6640 2352.97 2362.25 2358.57 2362.39 0.000498 3.4 2956.3 567.18 0.23

STREAM 5076 50-yr 20900 2352.97 2371.89 2361.21 2372.05 0.000193 3.81 8791.45 643.1 0.17

STREAM 5076 100-yr 23800 2352.97 2373.53 2361.62 2373.69 0.000178 3.9 9856.66 656.02 0.16

STREAM 4854 2-yr 6640 2352.59 2362.05 2357.77 2362.26 0.000613 4.2 2343.93 367.69 0.26

STREAM 4854 50-yr 20900 2352.59 2371.65 2361.08 2371.97 0.000355 5.41 6082.42 412.69 0.23

STREAM 4854 100-yr 23800 2352.59 2373.28 2361.73 2373.62 0.000337 5.58 6761.23 420.76 0.22

STREAM 4635 2-yr 6640 2348.13 2358.74 2358.74 2361.65 0.009256 13.85 522.72 98.68 0.96

STREAM 4635 50-yr 20900 2348.13 2366.19 2365.48 2371.29 0.006235 18.89 1370.91 133.41 0.89

STREAM 4635 100-yr 23800 2348.13 2367.79 2366.56 2372.95 0.005499 19.08 1599.46 152.18 0.86

STREAM 4365 2-yr 6640 2346.84 2357.86 2354.61 2358.7 0.002015 7.48 969.71 132.58 0.47

STREAM 4365 50-yr 20900 2346.84 2367.28 2360.18 2368.87 0.001378 10.45 2341.76 160.95 0.44

STREAM 4365 100-yr 23800 2346.84 2368.9 2361.09 2370.6 0.001313 10.83 2597.7 165.85 0.44

STREAM 4067 2-yr 6640 2345.93 2356.76 2354.21 2357.97 0.002765 8.9 794.18 113.71 0.55

STREAM 4067 50-yr 20900 2345.93 2365.88 2360.47 2368.21 0.002036 12.6 1899.99 150.96 0.53

STREAM 4067 100-yr 23800 2345.93 2367.44 2361.44 2369.94 0.001959 13.09 2093.56 157.62 0.53

STREAM 4013 2-yr 6640 2343.77 2356.83 2352.61 2357.62 0.00262 7.16 955.75 122.69 0.42

STREAM 4013 50-yr 20900 2343.77 2366.16 2358.9 2367.71 0.002113 10.34 2296.36 184.29 0.43

STREAM 4013 100-yr 23800 2343.77 2367.77 2359.89 2369.41 0.002015 10.68 2687.64 190.6 0.42

STREAM 4000

Bridge

STREAM 3965 2-yr 6640 2343.14 2355.98 2353.02 2357.26 0.006584 9.09 730.99 96.3 0.58

STREAM 3965 50-yr 20900 2343.14 2364.65 2359.9 2367.24 0.004962 13.03 1665.13 135.24 0.57

STREAM 3965 100-yr 23800 2343.14 2366.09 2360.92 2368.89 0.004811 13.58 1823.25 140.85 0.57

STREAM 3915 2-yr 6640 2342.49 2355.16 2353.06 2356.83 0.006846 10.39 640.56 84.14 0.65

STREAM 3915 50-yr 20900 2342.49 2361.96 2360.1 2366.4 0.008216 17.01 1273.45 107.56 0.79

STREAM 3915 100-yr 23800 2342.49 2362.97 2361.23 2367.95 0.008461 18.06 1369.59 110.88 0.81

STREAM 3816 2-yr 6640 2342.54 2354.54

2356.12 0.006625 10.08 658.55 85.37 0.64

STREAM 3816 50-yr 20900 2342.54 2361.28

2365.47 0.008131 16.44 1299.51 105.98 0.78

STREAM 3816 100-yr 23800 2342.54 2362.29 2360.26 2366.98 0.008317 17.42 1408.46 110.35 0.8

STREAM 3697 2-yr 6640 2342.92 2354.38

2355.32 0.003111 7.8 862.93 103.65 0.46

STREAM 3697 50-yr 20900 2342.92 2361.34

2364.14 0.004357 13.56 1648.79 122.12 0.6

STREAM 3697 100-yr 23800 2342.92 2362.4

2365.55 0.004525 14.43 1779.7 124.95 0.62

STREAM 3435 2-yr 6640 2341.22 2352.94

2354.23 0.00571 9.24 760.78 119.3 0.6

STREAM 3435 50-yr 20900 2341.22 2359.95

2362.88 0.005593 14.21 1697.01 147.48 0.66

STREAM 3435 100-yr 23800 2341.22 2361.11

2364.29 0.005509 14.85 1871.93 152.11 0.66

STREAM 3292 2-yr 6640 2339.7 2352.43

2353.3 0.005687 7.51 884.33 159.87 0.56

STREAM 3292 50-yr 20900 2339.7 2360.57

2361.81 0.002945 8.94 2351.03 198.34 0.45

STREAM 3292 100-yr 23800 2339.7 2361.89

2363.2 0.002747 9.19 2616.25 203.93 0.44

STREAM 3008 2-yr 6640 2338.58 2351.75

2352.55 0.003359 7.22 931.43 133.17 0.46

STREAM 3008 50-yr 20900 2338.58 2359.43

2361.25 0.003025 10.96 2049.45 157.94 0.5

STREAM 3008 100-yr 23800 2338.58 2360.64

2362.64 0.003008 11.5 2243.78 161.86 0.5

STREAM 2810 2-yr 6640 2340.52 2351.25

2352.02 0.002266 7.02 948.6 118.86 0.43

STREAM 2810 50-yr 20900 2340.52 2358.78

2360.71 0.002496 11.2 1940.64 142.85 0.5

STREAM 2810 100-yr 23800 2340.52 2359.95

2362.1 0.002519 11.82 2109.94 145.79 0.51

STREAM 2491 2-yr 6640 2340.04 2350.58

2351.38 0.002314 7.25 987.42 148.45 0.44

STREAM 2491 50-yr 20900 2340.04 2358.19

2360.01 0.002315 11.21 2211.28 172.92 0.5

STREAM 2491 100-yr 23800 2340.04 2359.39

2361.38 0.002325 11.79 2419.84 176.76 0.5

STREAM 2192 2-yr 6640 2339.08 2349.83

2350.66 0.002498 7.36 928.12 127.83 0.46

STREAM 2192 50-yr 20900 2339.08 2357.18

2359.25 0.002655 11.73 1969.66 155.47 0.53

STREAM 2192 100-yr 23800 2339.08 2358.32

2360.61 0.002686 12.37 2149.16 159.75 0.54

STREAM 1703 2-yr 6640 2338.59 2348.69

2349.52 0.002256 7.37 966.59 130.16 0.44

STREAM 1703 50-yr 20900 2338.59 2355.59

2357.87 0.002972 12.47 1926.83 149.33 0.56

STREAM 1703 100-yr 23800 2338.59 2356.62

2359.2 0.003087 13.27 2083.05 153.43 0.57

STREAM 1655.75* 2-yr 6640 2338.26 2348.5

2349.39 0.002684 7.62 905.5 125.74 0.47

STREAM 1655.75* 50-yr 20900 2338.26 2355.41

2357.73 0.00315 12.47 1880.45 152.99 0.57

STREAM 1655.75* 100-yr 23800 2338.26 2356.46

2359.05 0.00323 13.21 2042.81 157.07 0.58

STREAM 1608.5* 2-yr 6640 2337.93 2348.27

2349.25 0.003205 7.96 855.53 123.12 0.51

STREAM 1608.5* 50-yr 20900 2337.93 2355.16

2357.56 0.003475 12.63 1802.59 154.65 0.59

STREAM 1608.5* 100-yr 23800 2337.93 2356.22

2358.88 0.003512 13.32 1968.41 158.36 0.6

STREAM 1561.25* 2-yr 6640 2337.6 2348

2349.07 0.003686 8.33 810.43 119.71 0.54

STREAM 1561.25* 50-yr 20900 2337.6 2354.88

2357.38 0.003894 12.82 1730.68 146.26 0.62

STREAM 1561.25* 100-yr 23800 2337.6 2355.94

2358.7 0.003898 13.49 1887.21 151.11 0.63

STREAM 1514.* 2-yr 6640 2337.27 2347.71

2348.88 0.004191 8.68 771.95 115.53 0.58

STREAM 1514.* 50-yr 20900 2337.27 2354.53

2357.17 0.004496 13.16 1665.67 144.55 0.65

STREAM 1514.* 100-yr 23800 2337.27 2355.6

2358.49 0.004442 13.76 1823.85 148.37 0.66

STREAM 1466.75* 2-yr 6640 2336.93 2347.4

2348.66 0.004706 9.01 740.04 112.13 0.61

STREAM 1466.75* 50-yr 20900 2336.93 2354.07

2356.93 0.005017 13.65 1593.44 141.66 0.69

STREAM 1466.75* 100-yr 23800 2336.93 2355.14

2358.25 0.005008 14.24 1747.67 145.76 0.69

STREAM 1419.5* 2-yr 6640 2336.6 2347.05

2348.41 0.005377 9.37 709.51 110.23 0.64

STREAM 1419.5* 50-yr 20900 2336.6 2353.56

2356.65 0.005641 14.18 1521.74 138.62 0.73

STREAM 1419.5* 100-yr 23800 2336.6 2354.61

2357.97 0.005609 14.78 1670.46 142.67 0.73

STREAM 1372.25* 2-yr 6640 2336.27 2346.59 2345.1 2348.12 0.006498 9.91 670.34 108.71 0.7

STREAM 1372.25* 50-yr 20900 2336.27 2352.94 2351.01 2356.33 0.006475 14.82 1443.88 134.99 0.77

STREAM 1372.25* 100-yr 23800 2336.27 2353.98 2351.97 2357.65 0.006421 15.44 1586.1 139.18 0.78

STREAM 1325 2-yr 6640 2335.94 2344.97 2344.97 2347.57 0.014208 12.96 512.52 99.32 1.01

STREAM 1325 50-yr 20900 2335.94 2350.89 2350.89 2355.78 0.011371 17.78 1189.26 126.3 1

STREAM 1325 100-yr 23800 2335.94 2351.8 2351.8 2357.1 0.011181 18.5 1306.32 129.82 1

STREAM 1101 2-yr 6640 2333.67 2343.53 2342.02 2344.93 0.006001 9.47 703.88 118.41 0.68

STREAM 1101 50-yr 20900 2333.67 2349.58 2347.6 2352.84 0.006002 14.53 1486.58 139.67 0.75

STREAM 1101 100-yr 23800 2333.67 2350.52 2348.45 2354.11 0.006001 15.3 1618.04 142.41 0.76

PROPOSED Conditions HEC RAS MODEL

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)

STREAM 5076 2-yr 6640 2352.97 2362.25 2358.57 2362.39 0.000498 3.4 2956.3 567.18 0.23

STREAM 5076 50-yr 20900 2352.97 2371.89 2361.21 2372.05 0.000193 3.81 8791.45 643.1 0.17

STREAM 5076 100-yr 23800 2352.97 2373.53 2361.62 2373.69 0.000178 3.9 9856.81 656.02 0.16

STREAM 4854 2-yr 6640 2352.59 2362.05 2357.77 2362.26 0.000613 4.2 2343.93 367.69 0.26

STREAM 4854 50-yr 20900 2352.59 2371.65 2361.08 2371.97 0.000355 5.41 6082.42 412.69 0.23

STREAM 4854 100-yr 23800 2352.59 2373.28 2361.73 2373.62 0.000337 5.58 6761.33 420.77 0.22

STREAM 4635 2-yr 6640 2348.13 2358.74 2358.74 2361.65 0.009256 13.85 522.72 98.68 0.96

STREAM 4635 50-yr 20900 2348.13 2366.19 2365.48 2371.29 0.006234 18.89 1370.94 133.41 0.89

STREAM 4635 100-yr 23800 2348.13 2367.79 2366.56 2372.95 0.005498 19.08 1599.64 152.18 0.86

STREAM 4365 2-yr 6640 2346.84 2357.86 2354.61 2358.7 0.002015 7.48 969.71 132.58 0.47

STREAM 4365 50-yr 20900 2346.84 2367.28 2360.18 2368.87 0.001378 10.45 2341.84 160.96 0.44

STREAM 4365 100-yr 23800 2346.84 2368.9 2361.09 2370.6 0.001313 10.83 2597.86 165.85 0.44

STREAM 4067 2-yr 6640 2345.93 2356.76 2354.21 2357.97 0.002765 8.9 794.18 113.71 0.55

STREAM 4067 50-yr 20900 2345.93 2365.88 2360.47 2368.21 0.002036 12.6 1900.05 150.97 0.53

STREAM 4067 100-yr 23800 2345.93 2367.44 2361.44 2369.94 0.001958 13.09 2093.69 157.62 0.53

STREAM 4013 2-yr 6640 2343.77 2356.83 2352.61 2357.62 0.00262 7.16 955.75 122.69 0.42

STREAM 4013 50-yr 20900 2343.77 2366.16 2358.9 2367.71 0.002113 10.34 2296.47 184.29 0.43

STREAM 4013 100-yr 23800 2343.77 2367.77 2359.89 2369.41 0.002015 10.68 2687.83 190.6 0.42

STREAM 4000

Bridge

STREAM 3965 2-yr 6640 2343.14 2355.98 2353.02 2357.26 0.006584 9.09 730.99 96.3 0.58

STREAM 3965 50-yr 20900 2343.14 2364.65 2359.9 2367.24 0.004961 13.03 1665.21 135.24 0.57

STREAM 3965 100-yr 23800 2343.14 2366.09 2360.92 2368.89 0.00481 13.57 1823.36 140.85 0.57

STREAM 3915 2-yr 6640 2342.49 2355.16 2353.06 2356.83 0.006846 10.39 640.56 84.14 0.65

STREAM 3915 50-yr 20900 2342.49 2361.97 2360.1 2366.4 0.008211 17.01 1273.69 107.57 0.79

STREAM 3915 100-yr 23800 2342.49 2362.97 2361.23 2367.96 0.008448 18.05 1370.25 110.9 0.81

STREAM 3816 2-yr 6640 2342.54 2354.54

2356.12 0.006625 10.08 658.55 85.37 0.64

STREAM 3816 50-yr 20900 2342.54 2361.29

2365.47 0.008125 16.44 1299.87 106 0.78

STREAM 3816 100-yr 23800 2342.54 2362.3 2360.26 2366.98 0.0083 17.41 1409.46 110.38 0.79

STREAM 3697 2-yr 6640 2342.92 2354.38

2355.32 0.003111 7.8 862.93 103.65 0.46

STREAM 3697 50-yr 20900 2342.92 2361.34

2364.14 0.004354 13.56 1649.27 122.13 0.6

STREAM 3697 100-yr 23800 2342.92 2362.41

2365.56 0.004517 14.42 1780.86 124.98 0.62

STREAM 3435 2-yr 6640 2341.22 2352.94

2354.23 0.00571 9.24 760.78 119.3 0.6

STREAM 3435 50-yr 20900 2341.22 2359.95

2362.88 0.005583 14.21 1698.09 147.51 0.66

STREAM 3435 100-yr 23800 2341.22 2361.13

2364.3 0.005486 14.84 1874.72 152.18 0.66

STREAM 3292 2-yr 6640 2339.7 2352.43

2353.3 0.005687 7.51 884.33 159.87 0.56

STREAM 3292 50-yr 20900 2339.7 2360.58

2361.82 0.00294 8.94 2352.43 198.37 0.45

STREAM 3292 100-yr 23800 2339.7 2361.91

2363.21 0.002736 9.18 2619.63 204 0.44

STREAM 3008 2-yr 6640 2338.58 2351.75

2352.55 0.003359 7.22 931.43 133.17 0.46

STREAM 3008 50-yr 20900 2338.58 2359.44

2361.25 0.003019 10.95 2050.8 157.97 0.5

STREAM 3008 100-yr 23800 2338.58 2360.66

2362.65 0.002995 11.49 2247.18 161.93 0.5

STREAM 2810 2-yr 6640 2340.52 2351.25

2352.02 0.002266 7.02 948.6 118.86 0.43

STREAM 2810 50-yr 20900 2340.52 2358.79

2360.72 0.00249 11.2 1942.07 142.88 0.5

STREAM 2810 100-yr 23800 2340.52 2359.97

2362.11 0.002506 11.8 2113.57 145.85 0.51

STREAM 2491 2-yr 6640 2340.04 2350.58

2351.38 0.002314 7.25 987.42 148.45 0.44

STREAM 2491 50-yr 20900 2340.04 2358.21

2360.02 0.002309 11.2 2213.39 172.96 0.49

STREAM 2491 100-yr 23800 2340.04 2359.42

2361.4 0.002311 11.77 2425.02 176.85 0.5

STREAM 2192 2-yr 6640 2339.08 2349.83

2350.66 0.002498 7.36 928.12 127.83 0.46

STREAM 2192 50-yr 20900 2339.08 2357.2

2359.26 0.002645 11.71 1972.2 155.53 0.53

STREAM 2192 100-yr 23800 2339.08 2358.36

2360.64 0.002664 12.34 2155.4 159.9 0.54

STREAM 1703 2-yr 6640 2338.59 2348.69

2349.52 0.002256 7.37 966.59 130.16 0.44

STREAM 1703 50-yr 20900 2338.59 2355.61

2357.89 0.002954 12.45 1930.87 149.43 0.56

STREAM 1703 100-yr 23800 2338.59 2356.69

2359.24 0.003045 13.21 2093.06 153.68 0.57

STREAM 1655.75* 2-yr 6640 2338.26 2348.5

2349.39 0.002684 7.62 905.5 125.74 0.47

STREAM 1655.75* 50-yr 20900 2338.26 2355.44

2357.75 0.003128 12.45 1885.01 153.09 0.57

STREAM 1655.75* 100-yr 23800 2338.26 2356.53

2359.09 0.003181 13.15 2053.78 157.36 0.58

STREAM 1608.5* 2-yr 6640 2337.93 2348.27

2349.25 0.003205 7.96 855.53 123.12 0.51

STREAM 1608.5* 50-yr 20900 2337.93 2355.19

2357.58 0.003447 12.6 1807.72 154.77 0.59

STREAM 1608.5* 100-yr 23800 2337.93 2356.29

2358.93 0.00345 13.24 1980.8 158.63 0.6

STREAM 1561.25* 2-yr 6640 2337.6 2348

2349.07 0.003686 8.33 810.43 119.71 0.54

STREAM 1561.25* 50-yr 20900 2337.6 2354.92

2357.4 0.003858 12.78 1736.08 146.38 0.62

STREAM 1561.25* 100-yr 23800 2337.6 2356.02

2358.75 0.003819 13.41 1900.45 151.69 0.62

STREAM 1514.* 2-yr 6640 2337.27 2347.71

2348.88 0.004191 8.68 771.95 115.53 0.58

STREAM 1514.* 50-yr 20900 2337.27 2354.25

2357.16 0.004436 13.85 1626.05 143.5 0.66

STREAM 1514.* 100-yr 23800 2337.27 2355.28

2358.5 0.004465 14.59 1776.36 147.29 0.67

STREAM 1466.75* 2-yr 6640 2336.93 2347.4

2348.66 0.004706 9.01 740.04 112.13 0.61

STREAM 1466.75* 50-yr 20900 2336.93 2354.07

2356.93 0.005017 13.65 1593.44 141.66 0.69

STREAM 1466.75* 100-yr 23800 2336.93 2355.14

2358.25 0.005008 14.24 1747.67 145.76 0.69

STREAM 1419.5* 2-yr 6640 2336.6 2347.05

2348.41 0.005377 9.37 709.51 110.23 0.64

STREAM 1419.5* 50-yr 20900 2336.6 2353.56

2356.65 0.005641 14.18 1521.74 138.62 0.73

STREAM 1419.5* 100-yr 23800 2336.6 2354.61

2357.97 0.005609 14.78 1670.46 142.67 0.73

STREAM 1372.25* 2-yr 6640 2336.27 2346.59 2345.1 2348.12 0.006498 9.91 670.34 108.71 0.7

STREAM 1372.25* 50-yr 20900 2336.27 2352.94 2351.01 2356.33 0.006475 14.82 1443.88 134.99 0.77

STREAM 1372.25* 100-yr 23800 2336.27 2353.98 2351.97 2357.65 0.006421 15.44 1586.1 139.18 0.78

STREAM 1325 2-yr 6640 2335.94 2344.97 2344.97 2347.57 0.014208 12.96 512.52 99.32 1.01

STREAM 1325 50-yr 20900 2335.94 2350.89 2350.89 2355.78 0.011371 17.78 1189.26 126.3 1

STREAM 1325 100-yr 23800 2335.94 2351.8 2351.8 2357.1 0.011181 18.5 1306.32 129.82 1

STREAM 1101 2-yr 6640 2333.67 2343.53 2342.02 2344.93 0.006001 9.47 703.88 118.41 0.68

STREAM 1101 50-yr 20900 2333.67 2349.58 2347.6 2352.84 0.006002 14.53 1486.58 139.67 0.75

STREAM 1101 100-yr 23800 2333.67 2350.52 2348.45 2354.11 0.006001 15.3 1618.04 142.41 0.76

APPENDIX C

Culvert Hydraulics

Using HY 8

Station 1905+31

Station 1917+31

Station 1932+00

Station 1935+39

Station 1956+22

Station 1968+81 (Burr Creek)

Station 1974+89

Station 1984+66

Station 1999+06

Station 2001+91

Station 2014+36

Station 2023+46

Station 2048+58

Station 2051+60

Station 2054+19

Station 2075+23

Station 2087+14

Station 2089+35