mt-a0300461_WarmanLoopRoad_HydraulicsReport.pdf

Prepared for:

WESTERN FEDERAL LANDS HIGHWAY DIVISION

610 East Fifth Street, Vancouver, WA 98661

HYDRAULIC DESIGN MEMORANDUM

Warman Loop Road

MT BIGHORN 46(1)

IDIQ Contract No. DTFH7015D00007 Task Order No. 69056720F000015

September 2020

Prepared by:

ROBERT PECCIA &

ASSOCIATES

Helena, Montana

Warman Loop Road, MT BIGHORN 46(1)

Hydraulic Design Memorandum September 2020 i

TABLE OF CONTENTS

1.0 INTRODUCTION

1.1 This Memorandum

2.0 EXISTING DRAINAGE CHARACTERISTICS AND STRUCTURES

2.1 Existing Drainage Culvert Inventory and Assessment

3.0 HYDROLOGY

3.1 Drainage Basin Delineation

3.2 Design Flood Frequency

3.3 Drainage Culvert Hydrologic Estimates

4.0 HYDRAULICS

4.1 Proposed Culvert Analysis and Design

Figures

Figure 1: Project Vicinity Map

Tables

Table 1: War Man Creek Drainage Basin Area and Peak Flow Summary Table 2: War Man Creek Existing Culvert Summary Table 3: War Man Creek Proposed Culvert Summary

Photos Photo 1: Mountain Pocket Creek concrete box culvert under the Bighorn Canal .. 4 Photo 2: Proposed drainage structures at War Man Creek Photo 3: Flow control structure located downstream of Bighorn Canal bridge

Appendices

Appendix A: Culvert Assessment Report Appendix B: War Man Creek Drainage Basin Statistics Appendix C: Existing Culvert Capacity Analysis Appendix D: Proposed Culvert Capacity Analysis

September 2020 ii

ABBREVIATIONS/ACRONYMS

CFS Cubic Feet Per Second

CMP Corrugated Metal Pipe

CMPA Corrugated Metal Pipe Arch

FHWA Federal Highway Administration

MP Mile Post

PDDM Project Development and Design Manual

RCB Reinforced Concrete Box

SSPP Structural Steel Plate Pipe

USGS United States Geological Survey

WFLHD Western Federal Lands Highway Division

September 2020 1

1.0 INTRODUCTION

The Western Federal Lands Highway Division (WFLHD) of the Federal Highway Administration (FHWA), in partnership with Big Horn County, has requested engineering support for the Warman Loop Road capital improvement project. The purpose of the project is to provide safer and more adequate transportation access to and near the Bighorn Canyon National Recreation Area (BCNRA) for residents, recreationists, visitors and resource users. The construction contract is scheduled for advertisement in FY 2021, subject to available funding. Communications between Big Horn County and local stakeholders in the area have indicated an overwhelming amount of support for this project due to safety concerns and the current general unsatisfactory state of the roadway surface.

Big Horn County applied for funding for the Warman Loop Road project through the Federal Lands Access Program (FLAP). The scope of work is to pulverize the existing roadway, recondition and compact the pulverized surface, and overlay with a three-inch thick asphalt surface. Additional work includes replacement of minor culverts, one major culvert, subexcavation, bridge deck repairs, signage improvements, and pavement markings.

The project is located on the Crow Indian Reservation approximately 45 miles southeast of Billings, Montana along the Bighorn River. Warman Loop Road is a minor collector road approximately 4.2 miles in length and both starts and ends at intersections with Highway 313. The project begins at the northeastern intersection with Highway 313 and ends at the southwestern intersection. The Three Mile Access site for the Bighorn River, a road accessed by Warman Loop Road, attracts many anglers and supports several guide businesses and lodges. This fishing and public lands access site contributes significantly to the traffic volumes on Warman Loop Road and to the priority of this project.

The proposed project will closely follow the existing horizontal and vertical alignments of Warman Loop Road and will provide a roadway with a consistent 20-foot-wide paved surface.

A map showing the limits of the project and culvert locations is provided in Figure 1.

September 2020 2

Figure 1: Project Vicinity Map

1.1 THIS MEMORANDUM

This memorandum documents the preliminary hydraulic analysis and design recommendations for the existing drainage structures located along the project alignment. This memorandum discusses drainage characteristics, hydrologic and hydraulic assessments, and provides a summary of preliminary hydraulic recommendations.

2.0 EXISTING DRAINAGE CHARACTERISTICS AND

STRUCTURES

The project area lies in central Big Horn County on the Crow Reservation north of Fort Smith, Montana and in the Bighorn River valley. The project corridor falls within the Upper Yellowstone-Central Mountain hydrologic region as described in the United States Geological Survey Scientific Investigations Report 2015-5019.

The project alignment bisects level terrain between the foothills of the Bighorn Mountains to the south and the Bighorn River to the north. Drainage basin elevations along the project route range from approximately 5,600 feet above sea level near the top of the War Man Creek drainage to approximately 3,150 feet along the roadway.

War W Man M CreeC kk

September 2020 3

Warman Loop Road is located generally adjacent to the Bighorn Canal in the eastern half of the project and crosses farmlands in the western half. Two major drainages, Mountain Pocket Creek and War Man Creek, cross the project. Due to the presence of the canal, very few minor drainage basins cross the project; most existing culverts are part of the extensive Crow Irrigation Project.

2.1 EXISTING DRAINAGE CULVERT INVENTORY AND ASSESSMENT

A March 2020 hydraulic field reconnaissance was conducted to inventory and assess the condition of all existing drainage culverts along the 4.2-mile project corridor.

During the field reconnaissance, 17 mainline drainage culverts were noted along the project alignment.

Sixteen of the culverts are Corrugated Metal Pipe (CMP) ranging in size from 12-inches to 48-inches in diameter. Additionally, one drainage crossing (Mountain Pocket Creek) is a 108-inch diameter structural steel plate pipe (SSPP).

As part of the reconnaissance, the existing culvert milepost, size, type, existing condition, and remaining service life were reviewed and recorded. Field notes and photographs of each existing culvert were compiled in the Culvert Assessment Report, included in Appendix A. Subsequently, WFLHD surveyed each of the culverts as part of the topographical survey for the project.

In general, the existing culverts along the project alignment are in good condition. Eleven of the seventeen existing culverts convey irrigation flows from the Bighorn Canal:

• Eight of the eleven irrigation culverts require no action;

• One irrigation culvert requires cleaning; and

• Two irrigation culverts require replacement.

Because the flows in the irrigation culverts are controlled by head gates, no hydrology or hydraulic analysis will be performed for them. The two irrigation culverts that require replacement will be replaced in kind to maintain historic flows.

All the non-irrigation culverts appear adequately sized for their respective drainage basin except for the War Man Creek culvert at mile post (MP) 3.98. The County has reported issues with the creek overtopping the road.

3.0 HYDROLOGY

Per the project scope of work, not all existing drainage basins crossing the project alignment were delineated and analyzed. Instead, the culvert designs utilize and retain the culvert size, type, and recommendations as noted in the Culvert Assessment Report, with only limited adjustments.

Hydrologic methods described in the following sections of this memorandum were used to calculate peak flows in select basins.

3.1 DRAINAGE BASIN DELINEATION

United States Geological Survey (USGS) contour maps and the USGS StreamStats website (streamstats.usgs.gov/ss) were used to identify and delineate select drainage basins. In general, these basins are bound in the upper reach by the Bighorn Mountain’s foothills and in the lower reach by Warman Loop Road. Calculated drainage basin areas are listed in Table 1.

Two major drainage basins cross Warman Loop Road: Mountain Pocket Creek and War Man Creek.

September 2020 4

Mountain Pocket Creek is conveyed under Warman Loop Road by a 108-inch diameter SSPP. Sixty feet upstream of the SSPP, the creek is conveyed under the Bighorn Canal by an approximately five-foot wide by two-foot tall concrete box culvert, shown below.

Photo 1: Mountain Pocket Creek concrete box culvert under the Bighorn Canal

Because the flow to the roadway culvert is controlled by the much smaller canal culvert, no further analysis of the Mountain Pocket Creek drainage was performed.

One minor cross drain at MP 2.98 is slated for replacement. The adjacent topography is extremely flat (approximately ten feet of elevation change per mile) so delineating a drainage basin was not possible.

There is no evidence of roadway overtopping or erosion at the culvert, so it will be replaced in kind.

Based on the above discussion and the criteria listed in Section 3.0 of this report, only the drainage basin for War Man Creek was delineated and analyzed.

3.2 DESIGN FLOOD FREQUENCY

The project roadway parallels Montana Secondary Highway 313 and connects to the highway at both ends.

No critical infrastructure is accessed by the road. Therefore, this route is designated as a Low-Standard Road per subsection 7.1.6.1 of the FHWA Project Development and Design Manual (PDDM), and the design flood frequency for all culvert designs along the project corridor is the 25-year event per subsection

7.3.1.3.1 of the PDDM.

September 2020 5

3.3 DRAINAGE CULVERT HYDROLOGIC ESTIMATES

The USGS Regression Equations were utilized in determining flows in the War Man Creek drainage. The USGS Rural Regression Equations use statistical methods to draw conclusions from data at surrounding sites. They provide not only estimated peak flows, but also standard errors of prediction that define a probable range of accuracy. The project area is in the Upper Yellowstone-Central Mountain hydrologic region of Montana, and the variables used in the USGS equations include drainage basin area and mean annual precipitation. A mean annual precipitation of 20.1 inches was calculated with the USGS StreamStats program.

Peak discharges for the War Man Creek drainage basin were determined using USGS StreamStats program. Results obtained from the program are shown in Table 1 and calculations are included in Appendix B.

Table 1: War Man Creek Drainage Basin Area and Peak Flow Summary

MP Basin Area (acres)

Mean Annual Precipitation

(in)

Q10 (cfs)

Q25 (cfs)

Q50 (cfs)

3.98 10,752 20.1 333 648 966

4.0 HYDRAULICS

The initial step of the War Man Creek culvert design focused on an evaluation of existing culvert capacity and a comparison with calculated peak flows in the drainage basin. The existing culvert capacity calculations for the existing culverts in the War Man Creek drainage were completed using HY8-8.7.5. The analysis incorporated the existing drainage basin flows, local overtopping or controlling headwater elevations, and existing culvert data to analyze the capacity of each culvert. Results of this analysis are summarized in Table 2 and all calculations are included in Appendix C.

Table 2: War Man Creek Existing Culvert Summary

MP Existing Culvert

Existing Culvert

Cap.

(cfs)

Q25 Design Flow (cfs)

Existing Culvert

Undersized (Y/N)

Proposed Culvert

Notes

3.98 48" CMP 98

Yes 71”x47”

CMPA

Culvert crosses Warman Loop Road

3.98 42”x30”

CMPA

42 Yes Double cell 9’x5’ box culvert

Culvert discharges to Bighorn Canal

4.03 48" CMP 33 No N/A Culvert crosses Warman Loop Road

Three culverts convey War Man Creek during high flow events. A 48-inch diameter CMP under Warman Loop Road at MP 3.98 is the main culvert and conveys flows from west to east across the road. A 42-inch by 30-inch CMPA at MP 3.98 conveys water north into the Bighorn Canal. The inlet elevation of the CMPA is approximately 2.5 feet higher than the 48-inch CMP. When both culverts cannot accommodate the flow, September 2020 6 the water pools until it starts flowing through a second 48-inch CMP at MP 4.03, approximately 275 feet south of the main channel.

The existing culvert that conveys War Man Creek under Secondary 313 approximately 1,800 feet upstream of the Warman Loop Road crossing is a 137-inch by 87-inch CMPA.

Providing a culvert large enough to accommodate the design flow under Warman Loop Road is not feasible.

The existing stream channel is approximately six feet wide, and there is insufficient cover for a culvert with a rise greater than 48-inches. The grade of the road cannot be raised because the bridge over the Bighorn Canal is only 60 feet north of the culvert.

A general summary of the culvert design approach for replacement of the existing War Man Creek culverts is as follows:

• Replace the existing main channel 48-inch CMP at MP 3.98 with a 71-inch by 47-inch CMPA;

• Replace the existing 42-inch by 30-inch CMPA at MP 3.98 with a double cell, 9-foot by 5-foot concrete box culvert. The total structure width would be 20 feet, and the estimated length is 54 feet; and

• Leave the existing 48-inch CMP at MP 4.03 as is.

A rough sketch of the proposed structures at the War Man Creek crossing is shown below.

Photo 2: Proposed drainage structures at War Man Creek

Installing the box culvert would require additional roadway easement. The existing pipe culvert to be replaced is outside the existing 60-foot wide roadway easement. Also, an existing canal flow control structure is located immediately downstream (east) of the bridge in the Bighorn Canal, as shown below.

Consultation with the canal operator would be necessary to determine if introducing additional flow above the flow control structure is feasible.

September 2020 7

Photo 3: Flow control structure located downstream of Bighorn Canal bridge

4.1 PROPOSED CULVERT ANALYSIS AND DESIGN

The hydraulic design calculations for the proposed drainage culverts associated with the War Man Creek crossing were completed using HY8-8.7.5. The analysis incorporated the proposed drainage basin flows, local overtopping or controlling headwater elevations, and proposed culvert data to analyze the capacity of each of the proposed culverts. Results of the hydraulic analyses are summarized in Table 3 and the calculations are included in Appendix D.

Table 3: War Man Creek Proposed Culvert Summary

MP Existing Culvert

Dia.

(in)

Existing Culvert

Capacity (cfs)

Design Flow (cfs)

Proposed Culvert

Dia.

(in)

Proposed Culvert

Discharge (cfs)

Headwater Check

(HW/D<1.5)

3.98 48" CMP 98

71”x47”

CMPA

119 Yes

3.98 42”x30”

CMPA

42 Double cell 9’x5’ box culvert

572 Yes

4.03 48" CMP 33 48” CMP 15 Yes

Warman Loop Road

MT BIGHORN 46(1)

APPENDIX A: CULVERT ASSESSMENT REPORT

Prepared for:

WESTERN FEDERAL LANDS HIGHWAY DIVISION

610 East Fifth Street, Vancouver, WA 98661

CULVERT ASSESSMENT REPORT

Warman Loop Road

MT BIG HORN 46(1)

IDIQ Contract No. DTFH7015D00007

Task Order No. 69056720F000015

May 2020

Prepared by:

ROBERT PECCIA &

ASSOCIATES

Helena, Montana

Warman Loop Road, MT BIG HORN 46(1)

Robert Peccia and Associates Culvert Assessment Report May 2020 i

TABLE OF CONTENTS

1.0 Introduction

2.0 Existing Culvert Condition Survey

3.0 Culvert Deficiency Summary

Appendix A: Vicinity Map

Appendix B: Culvert Deficiency and Proposed Action Summary

Appendix C: Culvert Log Photos

Appendix D: Culvert Assessment Forms

LIST OF TABLES

Table 3-1: Culvert Deficiency Summary

May 2020 ii

ABBREVIATIONS/ACRONYMS

CMP Corrugated Metal Pipe

CMPA Corrugated Metal Pipe Arch

FHWA Federal Highway Administration

GPS Global Positioning System

M.P. Mile Post

NEPA National Environmental Policy Act

RPA Robert Peccia & Associates

WFLHD Western Federal Lands Highway Division

May 2020 1

1.0 INTRODUCTION

The Western Federal Lands Highway Division (WFLHD) of the Federal Highway Administration (FHWA), in cooperation with Big Horn County and the Crow Reservation, is proposing to complete the design documentation and National Environmental Policy Act (NEPA) for the Warman Loop Road improvement project. Warman Loop Road provides access to the Three Mile Parking Area used by anglers and recreationalists of the Bighorn River.

The proposed scope of work for the project includes:

Rehabilitate or reconstruct the existing pavement structure to provide a new asphalt concrete pavement (ACP) final surface.

Replacement of the existing ACP surface on the Bighorn Canal Bridge. Hydraulic sizing of culverts, replacing existing culverts and/or repairing existing culverts. (Approximately 14 minor “small” culverts and 2 major “large” culverts)

Permanent Traffic Control Devices including signing and striping Guardrail installation, if needed Staging and temporary traffic control to complete the work

The purpose of this report is to describe and document culvert conditions within the proposed project area.

Drainage improvement recommendations are based on measurements and visual observations taken by Robert Peccia and Associates (RPA) during culvert investigations conducted in March of 2020, and engineering judgment.

See the vicinity map in Appendix A for the general project location.

May 2020 2

2.0 EXISTING CULVERT CONDITION SURVEY

During the existing culvert condition survey, handheld tools, measurement instruments, handheld Global Positioning System (GPS) devices, and visual observations were used to assess the condition of the existing culverts located along Warman Loop Road. The culvert condition survey included documentation of the existing culvert location, type, and size as well as assessments of remaining service life, culvert deficiencies, and recommended actions. A complete description of the existing culverts along the noted park roads is detailed in the Culvert Deficiency and Proposed Action Summary included in Appendix B.

Field photos of various culverts and other areas of concern which may require improvement are included in Appendix C. The photo below illustrates a typical metal culvert in need of replacement.

Culvert Inlet Needing Replacement

3.0 CULVERT DEFICIENCY SUMMARY

Seventeen culverts were assessed, and several deficient culverts were noted along the roads. Noted culvert deficiencies included any existing condition that affected the performance of the existing culvert.

Common culvert deficiencies noted in the field included buried culvert inlet or outlets, damaged or crushed culverts, and corrosion of metal pipes. Engineering judgment was used to rate the severity of the noted culvert deficiencies and determine the need for drainage improvements. Based on the data gathered in March of 2020, culverts need to be cleaned, need to be repaired, or need to be replaced. Any culvert replacement underneath Warman Loop Road would have a minimum diameter of 24 inches.

The culvert located at M.P. 3.98 is unique among the other culverts inspected due to its repeated clogging and underperformance. The current culvert is a 48-inch CMP with a capacity of approximately 84 cfs., however, there is only approximately one additional foot of cover available to replace it with a larger pipe.

Based on the USGS regression equations and StreamStats, the basin Q25 is estimated to be 648 cfs. This leaves either a double barrel pipe or a box culvert to be options at this location.

May 2020 3

A summary of noted culvert deficiencies for culverts are listed in Table 3-1. The table also indicates if any environmental clearance may be necessary for the proposed drainage improvement action. A complete description of all existing culverts is included in Appendix B. Culvert assessment forms are included in Appendix D.

Table 3-1: Culvert Deficiency Summary

Road Name

Mile Post

Existing Diameter

(in.)

Inlet Condition

Outlet Condition

Action Remarks Environmental

Clearance Needed

Main 0.33 18 Good Good No Action No

Main 0.52 24 Good Partially Buried

No Action No

Main 0.78 24 Crushed Crushed Replace No

Main 0.79 24 Good Good No Action No

Main 1.25 30 Equiv. Corroded Partially Buried

No Action No

Main 1.28 108 Bent Good Clean No

Main 1.40 12 Corroded Corroded Replace No

Main 1.62 18 Partially Buried

Partially Buried

Clean No

Main 1.81 15 Partially Buried

Partially Buried

No Action No

Main 1.87 36 Equiv. Good Good Clean No

Main 2.16 12 Partially Buried

Partially Buried

Clean No

Main 2.65 24 Good Good No Action No

Main 2.86 24 Good Good No Action No

Main 2.98 24 Corroded Corroded Replace No

Main 3.14 18 Good Good No Action No

Main 3.98 48 Bent Good Replace Repeated clogging.

Undersized Yes

Main 4.03 48 Good Good No Action No

May 2020 4

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May 2020 A

Appendix A: Vicinity Map

May 2020 A

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May 2020 B

Appendix B: Culvert Deficiency and Proposed Action Summary

May 2020 B

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May 2020 C

Appendix C: Culvert Log Photos

May 2020 C

May 2020 C.1

Photo 2756: M.P. 0.33, 18‐inch CMP, No Action

Photo 2757: M.P. 0.33, 18‐inch CMP, No Action

May 2020 C.2

Photo 2758: M.P. 0.52, 24‐inch RCP, No Action

Photo 2759: M.P. 0.52, 24‐inch RCP, No Action

May 2020 C.3

Photo 2760: M.P. 0.78, 24‐inch CMP, Replace

Photo 2761: M.P. 0.78, 24‐inch CMP, Replace

May 2020 C.4

Photo 2762: M.P. 0.79, 24‐inch CMP, No Action

Photo 2763: M.P. 0.79, 24‐inch CMP, No Action

May 2020 C.5

Photo 2764: M.P. 1.25, 30‐inch Equiv. CMPA, No Action

Photo 2765: M.P. 1.25, 30‐inch Equiv. CMPA, No Action

May 2020 C.6

Photo 2766: M.P. 1.25, 30‐inch Equiv. CMPA, No Action

Photo 2767: M.P. 1.28, 108‐inch CMP, Clean

May 2020 C.7

Photo 2768: M.P. 1.28, 108‐inch CMP, Clean

Photo 2769: M.P. 1.28, 108‐inch CMP, Clean

May 2020 C.8

Photo 2770: M.P. 1.28, 108‐inch CMP, Clean

Photo 2771: M.P. 1.28, 108‐inch CMP, Clean

May 2020 C.9

Photo 2772: M.P. 1.28, 108‐inch CMP, Clean

Photo 2773: M.P. 1.40, 12‐inch CMP, Replace

May 2020 C.10

Photo 2774: M.P. 1.40, 12‐inch CMP, Replace

Photo 2775: M.P. 1.62, 18‐inch CMP, Clean

May 2020 C.11

Photo 2776: M.P. 1.62, 18‐inch CMP, Clean

Photo 2777: M.P. 1.81, 15‐inch CMP, No Action

May 2020 C.12

Photo 2778: M.P. 1.81, 15‐inch CMP, No Action

Photo 2779: M.P. 1.87, 36‐inch Equiv. CMPA, Clean

May 2020 C.13

Photo 2780: M.P. 1.87, 36‐inch Equiv. CMPA, Clean

Photo 2781: M.P. 2.16, 12‐inch CMP, Clean

May 2020 C.14

Photo 2782: M.P. 2.16, 12‐inch CMP, Clean

Photo 2783: M.P. 2.65, 24‐inch CMP, No Action

May 2020 C.15

Photo 2784: M.P. 2.65, 24‐inch CMP, No Action

Photo 2785: M.P. 2.86, 24‐inch CMP, No Action

May 2020 C.16

Photo 2786: M.P. 2.86, 24‐inch CMP, No Action

Photo 2787: M.P. 2.98, 24‐inch CMP, Replace

May 2020 C.17

Photo 2788: M.P. 2.98, 24‐inch CMP, Replace

Photo 2789: M.P. 3.14, 18‐inch CMP, No Action

May 2020 C.18

Photo 2790: M.P. 3.14, 18‐inch CMP, No Action

Photo 2791: M.P. 3.98, 48‐inch CMP, Replace

May 2020 C.19

Photo 2792: M.P. 3.98, 48‐inch CMP, Replace

Photo 2793: M.P. 3.98, 48‐inch CMP, Replace

May 2020 C.20

Photo 2794: M.P. 3.98, 48‐inch CMP, Replace

Photo 2800: M.P. 4.03, 48‐inch CMP, No Action

May 2020 C.21

Photo 2801: M.P. 4.03, 48‐inch CMP, No Action

May 2020 D

Appendix D: Culvert Assessment Forms

May 2020 D

APPENDIX B: WAR MAN CREEK DRAINAGE BASIN STATISTICS

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APPENDIX C: EXISTING CULVERT CAPACITY ANALYSIS

Project: Warman Loop Road Project Number: MT BIGHORN 46(1) By: S. Markwardt Date: September, 2020

EXISTING CULVERT HYDRAULIC ANALYSIS

DESIGN FLOWS

Q10 333.0 cfs Q25 648.0 cfs Q50 966.0 cfs

PROPOSED CONDITIONS

Sta. M.P. 3.98 Area Name War Man Creek Existing Pipe Rise (in.) 48 (48" dia. CMP)

PIPE DATA

Inv. In (ft) 3172.22 Inv. Out (ft) 3172.59 Length (ft) 52.00 Slope % -0.70 Skew (deg) 35 RT

ROADWAY DATA / SITE DATA

Overtopping Sta. M.P. 3.98 (Overtops Bighorn Canal access road) Overtop elevation (ft) 3178.06 Crest Width (ft) 24 Crest Length (ft) 50 Type App. Rd. LT.

OUTLET CHANNEL GEOMETRY

Bottom Width (ft) Channel Slope % 3172.8 ft Lt. Side Slope (_:1) Rt. Side Slope (_:1) Manning's (n)

Existing Culvert Capacity per Hy8 Run 97.54 cfs Ex. CMP

Q10 HW Elev. = Q25 HW Elev. = Q10 HW Depth = Q25 HW Depth = D D 1.5D 1.5D Meets Requirements Meets Requirements Notes:

3178.96 3179.97

No No

6.74 7.75 4.0' 4.0' 6.0' 6.0'

Constant tailwater (Bighorn Canal Normal WS

Elev.)

Q10 HW Check Q25 HW Check Ex. CMP Ex. CMP

Table 2 - Culvert Summary Table: M.P. 3.98: Ex. 48" CMP

Site Data - M.P. 3.98: 48" CMP Site Data Option: Culvert Invert Data Inlet Station: 0.00 ft

Inlet Elevation: 3172.22 ft Outlet Station: 52.00 ft

Outlet Elevation: 3172.59 ft Number of Barrels: 1

Culvert Data Summary - M.P. 3.98: 48" CMP Barrel Shape: Circular

Barrel Diameter: 4.00 ft

Barrel Material: Corrugated Steel

Embedment: 0.00 in

Barrel Manning's n: 0.0240

Culvert Type: Straight

Inlet Configuration: Thin Edge Projecting

Inlet Depression: None

Total Discharge

(cfs) Culvert

Discharge (cfs)

Headwater Elevation

(ft) Inlet

Control Depth (ft)

Outlet Control

Depth (ft) Flow Type Normal

Depth (ft) Critical Depth (ft) Outlet

Depth (ft) Tailwater Depth (ft)

Outlet Velocity

(ft/s) Tailwater Velocity

(ft/s)

333.00 110.71 3178.96 6.738 6.292 7-JA2c -1.000 3.177 3.177 6.640 10.095 0.000

396.30 113.89 3179.20 6.975 6.425 7-JA2c -1.000 3.218 3.218 6.640 10.257 0.000

459.60 116.69 3179.41 7.189 6.546 7-JA2c -1.000 3.254 3.254 6.640 10.412 0.000

522.90 119.21 3179.61 7.388 6.657 7-JA2c -1.000 3.285 3.285 6.640 10.546 0.000

586.20 121.53 3179.80 7.576 6.762 7-JA2c -1.000 3.314 3.314 6.640 10.670 0.000

648.00 123.64 3179.97 7.749 6.858 7-JA2c -1.000 3.338 3.338 6.640 10.792 0.000

712.80 125.70 3180.15 7.923 6.954 7-JA2c -1.000 3.362 3.362 6.640 10.907 0.000

776.10 127.63 3180.31 8.089 7.046 7-JA2c -1.000 3.384 3.384 6.640 11.015 0.000

839.40 129.48 3180.48 8.251 7.135 7-JA2c -1.000 3.404 3.404 6.640 11.119 0.000

902.70 131.22 3180.63 8.406 7.219 7-JA2c -1.000 3.423 3.423 6.640 11.216 0.000

966.00 132.87 3180.78 8.555 7.301 7-JA2c -1.000 3.440 3.440 6.640 11.321 0.000

By: S. Markwardt Date: September, 2020

EXISTING CULVERT HYDRAULIC ANALYSIS

DESIGN FLOWS

Q10 333.0 cfs Q25 648.0 cfs Q50 966.0 cfs

PROPOSED CONDITIONS

Sta. Bighorn Canal access road (M.P. 3.98 Mainline) Area Name War Man Creek Existing Pipe Rise (in.) 30 (42" x 30" CMPA)

PIPE DATA

Inv. In (ft) 3174.61 Inv. Out (ft) 3171.93 Length (ft) 48.70 Slope % 5.48 Skew (deg) N/A

ROADWAY DATA / SITE DATA

Overtopping Sta. M.P. 3.98 (Overtops Bighorn Canal access road) Overtop elevation (ft) 3178.06 Crest Width (ft) 24 Crest Length (ft) 50 Type App. Rd. LT.

OUTLET CHANNEL GEOMETRY

Bottom Width (ft) Channel Slope % 3172.8 ft Lt. Side Slope (_:1) Rt. Side Slope (_:1) Manning's (n)

Existing Culvert Capacity per Hy8 Run 42.23 cfs Ex. CMPA

Q10 HW Elev. = Q25 HW Elev. = Q10 HW Depth = Q25 HW Depth = D D 1.5D 1.5D Meets Requirements Meets Requirements Notes:

3178.96 3179.97

Constant tailwater (Bighorn Canal Normal WS

Elev.)

Q10 HW Check Q25 HW Check Ex. CMPA Ex. CMPA

No No

4.36 5.36 2.5' 2.5' 3.8' 3.8'

HY-8 Culvert Analysis Report – Existing Conditions Table 1 - Culvert Summary Table: M.P. 3.98 Appr.: Ex. 42" x 30" CMPA

Site Data - M.P. 3.98 Appr.: 42" x 30" CMPA Site Data Option: Culvert Invert Data Inlet Station: 0.00 ft

Inlet Elevation: 3174.61 ft Outlet Station: 48.70 ft

Outlet Elevation: 3171.93 ft Number of Barrels: 1

Culvert Data Summary - M.P. 3.98 Appr.: 42" x 30" CMPA Barrel Shape: Pipe Arch

Barrel Span: 42.00 in Barrel Rise: 29.00 in

Barrel Material: Steel or Aluminum Embedment: 0.00 in

Barrel Manning's n: 0.0250 Culvert Type: Straight

Inlet Configuration: Projecting Inlet Depression: None

Total Discharge

(cfs) Culvert

Discharge (cfs)

Headwater Elevation

(ft) Inlet

Control Depth (ft)

Outlet Control

Depth (ft) Flow Type Normal

Depth (ft) Critical Depth (ft) Outlet

Depth (ft) Tailwater Depth (ft)

Outlet Velocity

(ft/s) Tailwater

333.00 50.60 3178.96 4.357 2.351 5-S2n 1.320 1.891 1.387 6.640 11.287 0.000

396.30 52.55 3179.20 4.594 2.594 5-S2n 1.358 1.927 1.425 6.640 11.407 0.000

459.60 54.24 3179.41 4.808 2.811 5-S2n 1.391 1.958 1.457 6.640 11.510 0.000

522.90 55.76 3179.61 5.007 3.011 5-S2n 1.420 1.984 1.420 6.640 12.142 0.000

586.20 57.15 3179.80 5.195 3.199 5-S2n 1.448 2.007 1.509 6.640 11.716 0.000

648.00 58.40 3179.97 5.368 3.370 5-S2n 1.473 2.027 1.540 6.640 11.745 0.000

712.80 59.62 3180.15 5.542 3.542 5-S2n 1.498 2.046 1.569 6.640 11.771 0.000

776.10 60.77 3180.31 5.708 3.705 5-S2n 1.522 2.063 1.596 6.640 11.800 0.000

839.40 61.86 3180.48 5.870 3.863 5-S2n 1.545 2.079 1.620 6.640 11.852 0.000

902.70 62.89 3180.63 6.024 4.013 5-S2n 1.567 2.093 1.641 6.640 11.906 0.000

966.00 63.87 3180.78 6.174 4.159 5-S2n 1.588 2.107 1.588 6.640 12.465 0.000

By: S. Markwardt Date: September, 2020

EXISTING CULVERT HYDRAULIC ANALYSIS

DESIGN FLOWS

Q10 333.0 cfs Q25 648.0 cfs Q50 966.0 cfs

PROPOSED CONDITIONS

Sta. M.P. 4.03 Area Name War Man Creek Existing Pipe Rise (in.) 48 (48" dia. CMP)

PIPE DATA

Inv. In (ft) 3175.13 Inv. Out (ft) 3175.22 Length (ft) 48.70 Slope % -0.18 Skew (deg) 6 LT

ROADWAY DATA / SITE DATA

Overtopping Sta. M.P. 3.98 (Overtops Bighorn Canal access road) Overtop elevation (ft) 3178.06 Crest Width (ft) 24 Crest Length (ft) 50 Type App. Rd. LT.

OUTLET CHANNEL GEOMETRY

Bottom Width (ft) Channel Slope % 3172.8 ft Lt. Side Slope (_:1) Rt. Side Slope (_:1) Manning's (n)

Existing Culvert Capacity per Hy8 Run 32.74 cfs Ex. CMP

Q10 HW Elev. = Q25 HW Elev. = Q10 HW Depth = Q25 HW Depth = D D 1.5D 1.5D Meets Requirements Meets Requirements Notes:

3178.96 3179.97

Constant tailwater (Bighorn Canal Normal WS

Elev.)

Q10 HW Check Q25 HW Check Ex. CMP Ex. CMP

Yes Yes

3.83 4.84 4.0' 4.0' 6.0' 6.0'

Table 3 - Culvert Summary Table: M.P. 4.03: Ex. 48" CMP

Site Data - M.P. 4.03: 48" CMP Site Data Option: Culvert Invert Data Inlet Station: 0.00 ft

Inlet Elevation: 3175.13 ft Outlet Station: 48.70 ft

Outlet Elevation: 3175.22 ft Number of Barrels: 1

Culvert Data Summary - M.P. 4.03: 48" CMP Barrel Shape: Circular

Barrel Diameter: 4.00 ft

Barrel Material: Corrugated Steel

Embedment: 0.00 in

Barrel Manning's n: 0.0240

Culvert Type: Straight

Inlet Configuration: Thin Edge Projecting

Inlet Depression: None

Total Discharge

(cfs) Culvert

Discharge (cfs)

Headwater Elevation

(ft) Inlet

Control Depth (ft)

Outlet Control

Depth (ft) Flow Type Normal

Depth (ft) Critical Depth (ft) Outlet

Depth (ft) Tailwater Depth (ft)

Outlet Velocity

(ft/s) Tailwater

333.00 52.36 3178.96 3.481 3.830 7-A2c -1.000 2.168 2.168 6.640 7.531 0.000

396.30 57.74 3179.20 3.723 4.067 7-A2c -1.000 2.283 2.283 6.640 7.791 0.000

459.60 62.60 3179.41 3.947 4.281 7-A2c -1.000 2.383 2.383 6.640 8.019 0.000

522.90 67.08 3179.61 4.158 4.480 7-A2c -1.000 2.470 2.470 6.640 8.236 0.000

586.20 71.22 3179.80 4.359 4.668 7-A2c -1.000 2.547 2.547 6.640 8.436 0.000

648.00 74.96 3179.97 4.547 4.841 7-A2c -1.000 2.618 2.618 6.640 8.602 0.000

712.80 78.59 3180.15 4.734 5.015 7-A2c -1.000 2.682 2.682 6.640 8.773 0.000

776.10 81.91 3180.31 4.912 5.181 7-A2c -1.000 2.739 2.739 6.640 8.931 0.000

839.40 84.95 3180.48 5.078 5.343 7-A2c -1.000 2.790 2.790 6.640 9.075 0.000

902.70 89.49 3180.63 5.338 5.497 7-A2c -1.000 2.864 2.864 6.640 9.292 0.000

966.00 93.86 3180.78 5.599 5.647 7-A2c -1.000 2.933 2.933 6.640 9.503 0.000

Roadway Data for Crossing: Ex. War Man Creek Roadway Profile Shape: Constant Roadway Elevation

Crest Length: 50.00 ft

Crest Elevation: 3178.06 ft

Roadway Surface: Gravel

Roadway Top Width: 24.00 ft

APPENDIX D: PROPOSED CULVERT CAPACITY ANALYSIS

By: S. Markwardt Date: September, 2020

PROPOSED CULVERT HYDRAULIC ANALYSIS

DESIGN FLOWS

Q10 333.0 cfs Q25 648.0 cfs Q50 966.0 cfs

PROPOSED CONDITIONS

Sta. M.P. 3.98 Area Name War Man Creek Proposed Pipe Rise (in) 47 71" x 47" CMPA

PIPE DATA

Inv. In (ft) 3172.22 Inv. Out (ft) 3172.22 Length (ft) 52.00 Slope % 0.01 Skew (deg) 34 RT

ROADWAY DATA / SITE DATA

Overtopping Sta. M.P. 3.98 Overtop elevation (ft) 3177.11 Crest Width (ft) 22 Crest Length (ft) 50 Type Roadway at Sag - Bottom of surface section at sag

OUTLET CHANNEL GEOMETRY

Bottom Width (ft) Channel Slope % 3172.8 ft Lt. Side Slope (_:1) Rt. Side Slope (_:1) Manning's (n)

Proposed Culvert Capacity per Hy8 Run 118.71 cfs

CMPA

Q10 HW Elev. = Q25 HW Elev. = Q10 HW Depth = Q25 HW Depth = D D 1.5D 1.5D Meets Requirements Meets Requirements Notes:

3175.23 3176.85

Yes Yes

3.01 4.63 3.9' 3.9' 5.9' 5.9'

Constant tailwater (Bighorn Canal Normal WS

Elev.)

Q10 HW Check Q25 HW Check

CMPA CMPA

Table 2 - Culvert Summary Table: M.P. 3.98: 71"x47" CMPA

Site Data - M.P. 3.98: 71"x47" CMPA Site Data Option: Culvert Invert Data Inlet Station: 0.00 ft

Inlet Elevation: 3172.22 ft Outlet Station: 52.00 ft

Outlet Elevation: 3172.22 ft Number of Barrels: 1

Culvert Data Summary - M.P. 3.98: 71"x47" CMPA Barrel Shape: Pipe Arch

Barrel Span: 71.00 in

Barrel Rise: 47.00 in

Barrel Material: Steel or Aluminum

Embedment: 0.00 in

Barrel Manning's n: 0.0240

Culvert Type: Straight

Inlet Configuration: Projecting

Inlet Depression: None

Total Discharge

(cfs) Culvert

Discharge (cfs)

Headwater Elevation

(ft) Inlet

Control Depth (ft)

Outlet Control

Depth (ft) Flow Type Normal

Depth (ft) Critical Depth (ft) Outlet

Depth (ft) Tailwater Depth (ft)

Outlet Velocity

(ft/s) Tailwater

333.00 58.70 3175.23 2.753 3.004 7-H2c -1.000 1.660 1.660 6.640 6.874 0.000

396.30 70.17 3175.59 3.085 3.368 7-H2c -1.000 1.840 1.840 6.640 7.330 0.000

459.60 81.08 3175.93 3.395 3.707 7-H2c -1.000 1.992 1.992 6.640 7.776 0.000

522.90 91.47 3176.25 3.698 4.027 7-H2c -1.000 2.132 2.132 6.640 8.167 0.000

586.20 101.36 3176.56 3.999 4.334 7-H2c -1.000 2.264 2.264 6.640 8.510 0.000

648.00 110.49 3176.85 4.293 4.622 7-H2c -1.000 2.381 2.381 6.640 8.819 0.000

712.80 119.49 3177.14 4.603 4.915 7-H2c -1.000 2.490 2.490 6.640 9.131 0.000

776.10 125.76 3177.35 4.832 5.126 7-H2c -1.000 2.562 2.562 6.640 9.347 0.000

839.40 130.87 3177.53 5.027 5.305 7-H2c -1.000 2.620 2.620 6.640 9.524 0.000

902.70 135.36 3177.70 5.205 5.470 7-H2c -1.000 2.670 2.670 6.640 9.680 0.000

966.00 139.38 3177.85 5.371 5.626 7-H2c -1.000 2.714 2.714 6.640 9.819 0.000

By: S. Markwardt Date: September, 2020

PROPOSED CULVERT HYDRAULIC ANALYSIS

DESIGN FLOWS

Q10 333.0 cfs Q25 648.0 cfs Q50 966.0 cfs

PROPOSED CONDITIONS

Sta. M.P. 3.98 Area Name War Man Creek Proposed Pipe Rise (in) 60 9'x 5' Double Conc. Box Culvert

PIPE DATA

Inv. In (ft) 3172.22 Inv. Out (ft) 3171.93 Length (ft) 52.00 Slope % 0.56 Skew (deg) N/A

ROADWAY DATA / SITE DATA

Overtopping Sta. M.P. 3.98 Overtop elevation (ft) 3177.11 Crest Width (ft) 22 Crest Length (ft) 50 Type Roadway at Sag - Bottom of surface section at sag

OUTLET CHANNEL GEOMETRY

Bottom Width (ft) Channel Slope % 3172.8 ft Lt. Side Slope (_:1) Rt. Side Slope (_:1) Manning's (n)

Proposed Culvert Capacity per Hy8 Run 572.29 cfs Dbl. Conc. Box

Q10 HW Elev. = Q25 HW Elev. = Q10 HW Depth = Q25 HW Depth = D D 1.2D 1.2D Meets Requirements Meets Requirements Notes:

3175.23 3176.85

Constant tailwater (Bighorn Canal Normal WS

Elev.)

Q10 HW Check Q25 HW Check Dbl. Conc. Box Dbl. Conc. Box

Yes Yes

3.01 4.63 5.0' 5.0'

HY-8 Culvert Analysis Report – Proposed Conditions Table 1 - Culvert Summary Table: M.P. 3.98 Appr.: Double 9'x5' Conc. Box Culvert

Site Data - M.P. 3.98 Appr.: Double 9'x5' Conc. Box Culvert Site Data Option: Culvert Invert Data

Inlet Station: 0.00 ft

Inlet Elevation: 3172.22 ft

Outlet Station: 52.00 ft

Outlet Elevation: 3171.93 ft

Number of Barrels: 2

Culvert Data Summary - M.P. 3.98 Appr.: Double 9'x5' Conc. Box Culvert Barrel Shape: Concrete Box Barrel Span: 9.00 ft

Barrel Rise: 5.00 ft Barrel Material: Concrete

Embedment: 0.00 in

Barrel Manning's n: 0.0120

Culvert Type: Straight

Inlet Configuration: 1.5:1 Bevel (90º) Headwall

Inlet Depression: None

Total Discharge

(cfs) Culvert

Discharge (cfs)

Headwater Elevation

(ft) Inlet

Control Depth (ft)

Outlet Control

Depth (ft) Flow Type Normal

Depth (ft) Critical Depth (ft) Outlet

Depth (ft) Tailwater Depth (ft)

Outlet Velocity

(ft/s) Tailwater

333.00 274.29 3175.23 3.009 1.836 1-S2n 1.481 1.932 1.639 6.640 9.300 0.000

396.30 325.61 3175.59 3.373 2.147 1-S2n 1.662 2.166 1.850 6.640 9.780 0.000

459.60 376.26 3175.93 3.712 2.456 1-S2n 1.833 2.385 2.049 6.640 10.200 0.000

522.90 426.75 3176.25 4.032 2.767 1-S2n 1.997 2.594 2.241 6.640 10.579 0.000

586.20 477.07 3176.56 4.339 3.082 1-S2n 2.157 2.794 2.426 6.640 10.925 0.000

648.00 525.94 3176.85 4.627 3.393 1-S2n 2.308 2.982 2.600 6.640 11.236 0.000

712.80 576.75 3177.14 4.920 3.724 1-S2n 2.461 3.171 2.777 6.640 11.538 0.000

776.10 613.89 3177.35 5.131 3.970 5-S2n 2.572 3.306 2.903 6.640 11.747 0.000

839.40 645.51 3177.53 5.310 4.183 5-S2n 2.665 3.418 3.010 6.640 11.914 0.000

902.70 674.73 3177.70 5.475 4.383 5-S2n 2.749 3.521 3.107 6.640 12.064 0.000

966.00 702.28 3177.85 5.631 4.573 5-S2n 2.829 3.616 3.197 6.640 12.202 0.000

By: S. Markwardt Date: September, 2020

PROPOSED CULVERT HYDRAULIC ANALYSIS

DESIGN FLOWS

Q10 333.0 cfs Q25 648.0 cfs Q50 966.0 cfs

PROPOSED CONDITIONS

Sta. M.P. 4.03 Area Name War Man Creek Existing Pipe Rise (in.) 48 (48" dia. CMP)

PIPE DATA

Inv. In (ft) 3175.13 Inv. Out (ft) 3175.22 Length (ft) 48.70 Slope % -0.18 Skew (deg) 6 LT

ROADWAY DATA / SITE DATA

Overtopping Sta. M.P. 3.98 Overtop elevation (ft) 3177.11 Crest Width (ft) 22 Crest Length (ft) 50 Type Roadway at Sag - Bottom of surface section at sag

OUTLET CHANNEL GEOMETRY

Bottom Width (ft) Channel Slope % 3172.8 ft Lt. Side Slope (_:1) Rt. Side Slope (_:1) Manning's (n)

Proposed Culvert Capacity per Hy8 Run 15.37 cfs Ex. CMP

Q10 HW Elev. = Q25 HW Elev. = Q10 HW Depth = Q25 HW Depth = D D 1.5D 1.5D Meets Requirements Meets Requirements Notes:

3175.23 3176.85

Constant tailwater (Bighorn Canal Normal WS

Elev.)

Q10 HW Check Q25 HW Check Ex. CMP Ex. CMP

Yes Yes

0.10 1.72 4.0' 4.0'

Table 3 - Culvert Summary Table: M.P. 4.03: Ex. 48" CMP

Site Data - M.P. 4.03: Ex. 48" CMP Site Data Option: Culvert Invert Data Inlet Station: 0.00 ft

Inlet Elevation: 3175.13 ft Outlet Station: 48.70 ft

Outlet Elevation: 3175.22 ft Number of Barrels: 1

Culvert Data Summary - M.P. 4.03: Ex. 48" CMP Barrel Shape: Circular

Barrel Diameter: 4.00 ft

Barrel Material: Corrugated Steel

Embedment: 0.00 in

Barrel Manning's n: 0.0240

Culvert Type: Straight

Inlet Configuration: Thin Edge Projecting

Inlet Depression: None

Total Discharge

(cfs) Culvert

Discharge (cfs)

Headwater Elevation

(ft) Inlet

Control Depth (ft)

Outlet Control

Depth (ft) Flow Type Normal

Depth (ft) Critical Depth (ft) Outlet

Depth (ft) Tailwater Depth (ft)

Outlet Velocity

(ft/s) Tailwater

333.00 0.00 3175.23 0.000 0.000 0-A2c -1.000 0.000 0.000 6.640 4.227 0.000

396.30 0.51 3175.59 0.298 0.461 7-A2c -1.000 0.201 0.201 6.640 2.151 0.000

459.60 2.08 3175.93 0.607 0.801 7-A2c -1.000 0.412 0.412 6.640 3.047 0.000

522.90 4.55 3176.25 0.906 1.121 7-A2c -1.000 0.613 0.613 6.640 3.736 0.000

586.20 7.75 3176.56 1.192 1.428 7-A2c -1.000 0.806 0.806 6.640 4.283 0.000

648.00 11.43 3176.85 1.461 1.716 7-A2c -1.000 0.982 0.982 6.640 4.770 0.000

712.80 15.76 3177.14 1.733 2.008 7-A2c -1.000 1.161 1.161 6.640 5.204 0.000

776.10 19.23 3177.35 1.927 2.218 7-A2c -1.000 1.285 1.285 6.640 5.518 0.000

839.40 22.38 3177.53 2.093 2.397 7-A2c -1.000 1.392 1.392 6.640 5.756 0.000

902.70 25.44 3177.70 2.247 2.562 7-A2c -1.000 1.485 1.485 6.640 5.990 0.000

966.00 28.45 3177.85 2.394 2.718 7-A2c -1.000 1.577 1.577 6.640 6.181 0.000

Roadway Data for Crossing: Warman Stream-4 Roadway Profile Shape: Constant Roadway Elevation

Crest Length: 50.00 ft

Crest Elevation: 3177.11 ft

Roadway Surface: Paved

Roadway Top Width: 24.00 ft