Taylor_Mountain_UT2500(1)_Hydraulics_Report.pdf

Taylor Mountain Road Uintah County, UT

UT FLAP 2500(1)

Final Hydraulic Report

Federal Highway Administration Central Federal Lands Highway Division

14 January 2021

Executive Summary Hydrologic and hydraulic analyses were conducted for the UT FLAP 2500(1) Taylor Mountain Road project in Uintah County, UT. There were nine existing culvert locations identified in the project survey. In addition, there were multiple potential additional culvert locations identified during the project scoping.

The hydraulic capacity evaluation was based on a 25-year frequency based on a low standard road classification. Additionally, a 100-year check frequency was used to evaluate the Spring Creek culvert at station 185+11 because it is located within a FEMA Zone A floodplain. For existing culvert locations, a detailed evaluation was conducted using HY-8. For added culvert locations, the evaluation assumed inlet control to estimate proposed culvert capacity. The recommended replacement culvert types, sizes and inverts are shown in the following tables:

Summary of Culvert Recommendations – Existing Culvert Locations

Station Existing Culvert

Proposed Culvert Recommendation

85+15 18" CMP 18" Do not disturb existing culvert 151+01 24" CMP (2) 30" Replace culvert, add end sections, outlet protection (Class 3) 163+95 18" CMP 18" Do not disturb existing side culvert 170+81 24" CMP (2) 30" Replace culvert, add end sections, outlet protection (Class 3) 185+11 60" CMP (2) 72” Replace culvert, add headwall, outlet protection (Class 4) 207+95 30" CMP 30" Do not disturb existing culvert, add inlet headwall 217+39 30" CMP 24" Replace culvert, add end sections, outlet protection 256+16 18" CMP 18" Do not disturb existing culvert 276+83 36" CMP (2) 48” Replace culvert, add headwall, outlet protection (Class 4)

Summary of Culvert Recommendations – Added Culvert Locations

Station Proposed Culvert Recommendation 62+87 24" New culvert, add end sections, outlet protection (Class 2) 95+32 24" New culvert, add end sections, outlet protection (Class 2)

141+17 30" New culvert, add end sections, outlet protection (Class 3) 156+73 24" New culvert, add end sections, outlet protection (Class 2) 202+65 24" New culvert, add end sections, outlet protection (Class 2) 205+35 24" New culvert, add end sections, outlet protection (Class 2) 222+36 24" New culvert, add end sections, outlet protection (Class 2) 235+07 24" New culvert, add end sections, outlet protection (Class 2) 239+08 42" New culvert, add end sections, outlet protection (Class4) 245+42 48" New culvert, add end sections, outlet protection (Class 4) 260+41 24" New culvert, add end sections, outlet protection (Class 2) 293+00 24" New culvert, add end sections, outlet protection (Class 2)

Station Proposed Culvert Recommendation 330+00 24" New culvert, add end sections, outlet protection (Class 2) 373+45 24" New culvert, add end sections, outlet protection (Class 2) 380+49 24" New culvert, add end sections, outlet protection (Class 2) i UT2500(1) Taylor Mountain Road - Hydraulic Report

Table of Contents

1 Project Background Information

2 Hydraulic Design Criteria

3 Hydrology

3.1 Hydrologic Setting

3.2 FEMA Flood Insurance Study

3.3 Available Hydrologic Data

3.4 Major Basin Hydrology – Spring Creek

3.4.1 Precipitation

3.4.2 Basin Parameters

3.4.3 Peak Flow Results

3.5 Minor Basin Hydrology

4 Hydraulic Analysis

4.1 Existing Culvert Hydraulics

4.2 Proposed Culvert Hydraulics

4.3 Floodplain Regulations Compliance

5 Recommendations

6 References ii UT2500(1) Taylor Mountain Road - Hydraulic Report

Tables Table 1: Hydraulic Design Criteria Table 2: Major Basin Properties Table 3: Available Peak Streamflow Information Table 4: NOAA Atlas 14 24-Hour Point Precipitation Table 5: Unnamed Drainage Basin Parameters (NRCS Method) Table 6: Design Peak Flows for Major Basins Table 7: Minor Basin Rational Method Peak Flow – Existing Culverts Table 8: Minor Basin Rational Method Peak Flow – Proposed Culverts Table 9: Existing Culvert Characteristics Table 10: Existing Culvert Results Table 11: Required Culvert Size – Existing Culvert Locations Table 12: Required Culvert Size – Added Culvert Locations Table 13: Proposed vs Existing 100-Year Base Flood Elevations Table 14: Summary of Culvert Recommendations – Existing Culvert Locations Table 15: Summary of Culvert Recommendations – Added Culvert Locations

Figures

Figure 1: Project location map Figure 2: HUC Subwatersheds

Appendices

Appendix A: Hydrologic Analyses Appendix B: Hydraulic Analyses

Page 1 UT2500(1) Taylor Mountain Road - Hydraulic Report

1 PROJECT BACKGROUND INFORMATION

The project is located in Uintah County along Taylor Mountain Road (FSR044), see Figure 1. The existing roadway is one lane in each direction. The existing paved width varies from 16 to 28 feet, the existing roadway drainage ranges from fair to poor, with ditch erosion, head cutting at culverts, and insufficient ditches in locations. The proposed project will widen the paved width to a consistent 22 feet and add a 1-foot shoulder. The scope of the project includes roadway widening, minor earthwork, grading, paving, and drainage improvements.

Figure 1: Project location map.

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2 HYDRAULIC DESIGN CRITERIA

The Federal Lands Highway Project Development and Design Manual (PDDM) (Federal Lands Highway 2012) establishes the hydraulic design criteria. Based on the project scoping report the road has a design speed of 35 mph and a design average daily traffic (ADT) of 300-600 vehicles, based on these parameters the road is classified as low standard road for hydraulic design purposes. The applicable design criteria are listed in Table 1.

Table 1: Hydraulic Design Criteria

Road Classification: Low-Standard Road Culverts:

Design Frequency Check Frequency Allowable Headwater

25-year flood Overtopping flood

Minimum of:

• Bottom of aggregate base layer

• HW/D ratio of 1.2 for D > 48", 1.5 for D ≤ 48”

• Unacceptable hazard to human life or property

Floodplain Encroachment:

Design

Frequency Check Frequency Allowable Rise in Base Flood Elevation

100-year flood

Overtopping flood not to exceed 500-year flood

• 0.00’ for Floodway (no encroachment) or CLOMR required.

• ≤1.0’ no defined floodway, no detailed study, or unregulated zone

• Follow local standards if more stringent

Ditches:

Design

Frequency Stability Depth

10-year flood 10-year Flood • New: WSEL ≤ bottom of aggregate base layer

• Existing: WSEL ≤ shoulder hinge point Pavement Drainage:

Design Frequency Spread Depth

10-year flood, 50-year in sumps

Half of one travel lane

• On-grade and Sags: Allowable spread, not to exceed curb height

• Sumps and Parking Areas: 6”

Page 3 UT2500(1) Taylor Mountain Road - Hydraulic Report

3 HYDROLOGY

3.1 HYDROLOGIC SETTING

According to the USGS National Map (U.S. Geological Survey 2018) the southern 2 miles of the project are located within the Steinaker Reservoir Subwatershed (HUC12: 140600100901), and the northern 5.5 miles are located within the Spring Creek-Ashley Creek Subwatershed (HUC12: 140600100805), see Figure 2.

The major streams within the project are Spring Creek and an unnamed tributary to Spring Creek which cross Taylor Mountain Road at station 185+11 and station 276+83, respectively. Spring Creek generally flows from north to south to the confluence with Ashley Creek, located approximately 1.4 miles west from the crossing at Taylor Mountain Road. The contributing drainage basins to the two major crossings were delineated using available LiDAR derived 1-meter digital elevation model (DEM) information obtained from the USGS National Map. The LiDAR data was collected in 2018. The general basin properties are shown in Table 2. A drainage basin map is included in Appendix A.

Figure 2: HUC Subwatersheds

Page 4 UT2500(1) Taylor Mountain Road - Hydraulic Report

Table 2: Major Basin Properties

Project Station Stream Crossing Description Drainage Area

(mi2) Mean Basin

Elevation (ft) 185+09 Spring Creek Existing 60” CMP 9.4 7,090

276+90 Unnamed Spring Creek Tributary Existing 36" CMP 4.3 7,613

3.2 FEMA FLOOD INSURANCE STUDY

According to FEMA Flood Insurance Rate Map (FIRM) panels 49047C0475D the Spring Creek culvert at station 185+11 is located in FEMA Zone A. Zone A is classified as a special flood hazard area (SFHA).

Because detailed hydraulic analyses have not been performed, no Base Flood Elevations (BFEs) or flood depths are shown in the FIRM for Zone A. The SFHA comprises the land area that is shown in the FIRM as being inundated by the base flood and where the National Flood Insurance Program's (NFIP) floodplain management regulations apply. An excerpt of the applicable FIRM is shown in Appendix A. Coordination with the Uintah County floodplain administrator will be required at this location and a floodplain development permit is likely to be required. Chapter 17.26 of the Uintah County Code of Ordinances. No adverse impacts to base flood elevations (BFE) at any point in the NFIP community are expected to be caused by the project.

3.3 AVAILABLE HYDROLOGIC DATA

There are no USGS streamflow stations on Spring Creek within the project limits. The closest active streamflow station is located on Ashley Creek located approximately 3.7 miles upstream of the confluence with Spring Creek. In addition, there are two inactive stations on Ashley Creek located 0.7 miles upstream and 1.2 miles downstream of the confluence with Spring Creek, respectively. Table 3 summarizes the available peak streamflow information. Due to the size of the drainage basins compared to the project basin of interest and lack of active information the streamflow data was not used for the project.

Table 3: Available Peak Streamflow Information

USGS

Station

Location Latitude Longitude Drainage Area

Period of Record

Total Years Status

09266500 Ashley Creek, near Vernal UT 40°34'39" 109°37'17" 101 mi2 1912 - 2019 107 Active

09267100 Ashley Creek, above Dry Fork, near Vernal UT

40°32'16" 109°36'33" 110 mi2 1969 - 1972 4 Inactive

09271000 Ashley Creek, Sign of the Maine, near

Vernal UT 40°31'02" 109°35'45" 241 mi2 1900-1965 31 Inactive

Page 5 UT2500(1) Taylor Mountain Road - Hydraulic Report

3.4 MAJOR BASIN HYDROLOGY – SPRING CREEK

The USGS developed regressions for Utah that relate peak flow to basin and climate characteristics. The equations and limitations are documented in USGS Report 2007-5158 (Kenney, Wilkowske and Wright 2008). The project is located in geohydrologic Region 4. The Utah Region 4 peak flow regression equations were developed using the following ranges of the predictor variables:

• Drainage area: 2.95 to 667 square miles

• Mean basin elevation: 8,130 to 10,900 feet.

• Mean basin slope: 9.67 to 40.3 percent.

The Spring Creek basins fall outside the applicable range of the regression equations due to a lower mean basin elevation. Therefore, a HEC-HMS rainfall-runoff model was used to estimate peak flows for the major basins as described in the following sections.

3.4.1 Precipitation

The point precipitation values for the project were obtained from NOAA Atlas 14 Volume 1 (Bonnin, et al.

2011) using the Precipitation Frequency Data Server (National Oceanic and Atmospheric Administration 2011). The point precipitation values are assumed to represent precipitation over the entire basin. The point precipitation for a duration of 24 hours and various return periods are shown in Table 4.

Table 4: NOAA Atlas 14 24-Hour Point Precipitation

Percent Chance Exceedance (%)

Return Period (year)

Point Precipitation (inches)

50 2 1.26 20 5 1.57 10 10 1.84 4 25 2.21 2 50 2.51 1 100 2.83

0.2 500 3.65

An SCS Type II temporal distribution was selected for the project following guidance from the UDOT Drainage Manual (Utah Department of Transportation 2018).

3.4.2 Basin Parameters

The NRCS curve number (CN) method (Natural Resources Conservation Service 1997) was used to estimate runoff. A composite CN for the basins was estimated using SSURGO soil information (Natural Resources Conservation Service 2015) and the 2011 national land cover dataset (Multi-Resolution Land Characteristics Consortium 2018). Soils within the Spring Creek drainage basin are classified predominately as hydrologic soil groups (HSG) A and D. Land cover consists primarily evergreen forest, shrub/scrub, and grassland/herbaceous classes. Detailed CN computations are included in Appendix A.

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The NRCS lag time equation and unit hydrograph were used to estimate peak flows from the basins. A summary of basin parameters is shown in Table 5.

Table 5: Unnamed Drainage Basin Parameters (NRCS Method)

Station Basin Drainage Area (mi2

Composite

CN

Mean Basin Slope

Basin Length (mi)

Lag Time (hr)

185+09 Spring Creek 9.4 68.5 26.5 6.83 1.51

276+90 Unnamed

Spring Creek Tributary

4.3 68.5 22.9 5.39 1.34

3.4.3 Peak Flow Results

The hydrologic computations were carried out using HEC-HMS (U.S. Army Corps of Engineers 2017) using the parameters described in preceding sections. The design flows for the two major crossings are shown in Table 6. Additional details of the hydrologic analysis are provided in Appendix A.

Table 6: Design Peak Flows for Major Basins

Percent Chance Exceedance (%)

Return Period (year)

Station 185+09 Spring Creek

Peak Flow (cfs)

Station 276+90 Unnamed Spring Creek

Tributary Peak Flow (cfs)

50 2 14 6 20 5 59 28 10 10 139 68 4 25 309 152 2 50 490 243 1 100 720 359

0.2 500 1,442 723

3.5 MINOR BASIN HYDROLOGY

There are 7 existing minor culvert locations within the project limits. These locations were evaluated for replacement. In addition, there are multiple locations that were identified during project scoping as potential culvert additions. The existing culverts are corrugated metal pipes that range in diameter from 18 to 30 inches. The contributing basins to the minor culverts were delineated using the DEM information previously described. A drainage basin map is included in Appendix A.

The rational method (Federal Highway Administration 2002) was used to estimate peak flow from the minor basins. The time of concentration was estimated using the Kerby-Kirpich method for overland and channel flow. A minimum time of concentration of 5 minutes was assumed for all basins. Rainfall intensity-duration-frequency (IDF) curves were obtained from the NOAA Precipitation Frequency Data Server referenced previously. A runoff coefficient (C) of 0.2 was assumed based on undeveloped basins.

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Existing and proposed culvert peak flow results for the 25 and 100 year return periods are shown in Table 8 and Table 8, respectively.

Table 7: Minor Basin Rational Method Peak Flow – Existing Culverts

Station Drainage Area (acres)

Time of Concentration

(min)

Rational Runoff

Coefficient (C)

25-year Rainfall

Intensity (in/hr)

100-year Rainfall

Intensity (in/hr)

25-year Peak

Flow (cfs)

100-year Peak Flow

(cfs)

85+15 15.5 15.8 0.2 2.6 3.7 7.9 11.6 151+01 144.0 32.8 0.2 1.7 2.4 47.6 69.6 163+95 19.6 17.1 0.2 2.4 3.6 9.5 14.0 170+81 91.9 25.7 0.2 1.9 2.8 35.4 51.8 207+96 75.4 26.4 0.2 1.9 2.8 28.6 41.8 217+39 33.6 16.9 0.2 2.5 3.6 16.5 24.1 256+16 4.5 15.6 0.2 2.6 3.8 2.3 3.4

Table 8: Minor Basin Rational Method Peak Flow – Proposed Culverts

Station Drainage Area (acres)

Time of Concentration

(min)

Rational Runoff

Coefficient (C)

25-year Rainfall

Intensity (in/hr)

100-year Rainfall

Intensity (in/hr)

25-year Peak

Flow (cfs)

100-year Peak Flow

(cfs)

62+87 1.2 12.4 0.2 2.9 4.2 0.7 1.0 95+32 30.3 20.3 0.2 2.2 3.2 13.4 19.7

141+17 41.6 9.1 0.2 3.3 4.9 27.6 40.4 156+73 6.3 12.7 0.2 2.8 4.2 3.6 5.3 202+65 7.6 11.0 0.2 3.1 4.5 4.6 6.8 205+35 0.8 12.2 0.2 2.9 4.3 0.5 0.7 222+36 20.4 16.3 0.2 2.5 3.7 10.2 14.9 235+07 26.5 15.2 0.2 2.6 3.8 13.7 20.1 239+08 217.3(1) 34.1 0.2 1.6 2.4 70.0 102.4 245+42 259.2(1) 30.2 0.2 1.7 2.5 90.3 132.1 260+41 12.4 18.5 0.2 2.3 3.4 5.8 8.4 293+00 7.6 13.4 0.2 2.8 4.1 4.2 6.2 330+00 14.4 15.4 0.2 2.6 3.8 7.4 10.9 373+45 1.5 9.9 0.2 3.2 4.7 1.0 1.4 380+49 0.7 10.5 0.2 3.1 4.6 0.5 0.7

(1) Although the rational method is limited to drainage areas of 200 acres or less according to the PDDM it was selected for these basins because it produced more conservative results than the NRCS method described in Section 3.4.

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4 HYDRAULIC ANALYSIS

4.1 EXISTING CULVERT HYDRAULICS

The hydraulic performance of the existing culverts was evaluated using HY-8 (Federal Highway Administration 2017). The existing culvert characteristics shown in Table 9 were obtained from the project field survey. The overtopping elevations are edge of pavement elevations at the crossing location.

Overtopping was modeled as a broad crested weir having a constant crest elevation. Tailwater was assumed to be normal depth in the downstream channel.

Table 9: Existing Culvert Characteristics

Station Type Diameter Length (ft) Upstream Invert (ft)

Downstream Invert (ft)

Road Overtopping Elevation (ft)

85+15 CMP 18" 150.0 6071.8 6060.5 6085.4

151+01 CMP 24" 60.6 5988.2 5988.0 5992.3

163+95 CMP 18" 41.2 6007.7 6006.2 6009.1

170+81 CMP 24" 60.7 6017.3 6016.1 6020.5

185+11 CMP 60" 81.7 6017.6 6014.8 6030.4

207+96 CMP 30" 48.5 6104.9 6103.4 6109.7

217+39 CMP 30" 28.1 6132.4 6132.3 6135.6

256+16 CMP 18" 36.1 N/A N/A 6261.3

276+83 CMP 36” 60.6 6298.1 6295.2 6303.3

Notes:

(1) These elevations would cause water to flow into the roadside ditch to the east and overtop the road east of the culvert location.

The headwater results for the existing culverts are shown in Table 10. According to the results, various existing culverts meet design criteria. Depending on the culvert condition these could remain in place or be replaced in kind. A. A 10-year design frequency was evaluated for the culvert at station 163+95 because it is located on the roadside ditch. Additional details of the hydraulic analyses are provided in Appendix B.

Table 10: Existing Culvert Results

Station Design Frequency

Design Flow (cfs)

Headwater Elevation

(ft)

Headwater Depth (ft)

HW/D

Ratio

Overtops

Meets Capacity Design Criteria

85+15 25-year 7.9 6073.8 2.0 1.3 No Yes 151+01 25-year 47.6 5992.5 4.3 2.2 Yes No 163+95 10-year 9.5 6009.2 1.5 1.0 Yes No 170+81 25-year 35.4 6020.6 3.3 1.7 Yes No 185+11 25-year 309.0 6031.1 13.5 2.7 Yes No 207+96 25-year 28.6 6108.3 3.4 1.4 No Yes

Page 9 UT2500(1) Taylor Mountain Road - Hydraulic Report

217+39 25-year 16.5 6134.8 2.4 0.9 No Yes 256+16 25-year 2.3 6259.3 1.0 0.6 No Yes 276+83 25-year 152.0 6303.8 5.7 1.9 Yes No

4.2 PROPOSED CULVERT HYDRAULICS

Required sizes for the existing culvert locations that did not meet capacity criteria were estimated using HY-8 using the same hydrology and assumptions described in the existing conditions calculations. Due to cover limitations at some existing locations double barrel pipes are proposed. Required sizes for added culvert locations were estimated by developing discharge rating curves for each pipe diameter. An inlet control assumption was used in the analysis. Circular pipes are assumed for the added culverts. Equivalent size culverts can be used if cover is a constraint. The required culvert results for the existing locations and added locations are shown in Table 11 and Table 12, respectively. Additional details of the hydraulic analyses are provided in Appendix B.

Table 11: Required Culvert Size – Existing Culvert Locations

Station Proposed Culvert Design Flow (cfs)

Headwater Elevation

(ft)

Headwater Depth (ft)

HW/D

Ratio

Meets Capacity Design Criteria

151+01 (2) 30" 47.6 5991.4 3.2 1.3 Yes 170+81 (2) 30" 35.4 6019.6 2.3 0.9 Yes 185+11 (2) 72” 309.0 6022.6 5.9 1.0 Yes 276+83 (2) 48” 152.0 6301.5 4.0 1.0 Yes

Table 12: Required Culvert Size – Added Culvert Locations

Station Proposed Culvert

25-Year Design Flow (cfs)

Maximum Flow for

1.5 HW/D Ratio

(ft) Meets Capacity Design Criteria

62+87 24" 0.7 17.8 Yes 95+32 24" 13.4 17.8 Yes

141+17 30" 27.6 32.3 Yes 156+73 24" 3.6 17.8 Yes 202+65 24" 4.6 17.8 Yes 205+35 24" 0.5 17.8 Yes 222+36 24" 10.2 17.8 Yes 235+07 24" 13.7 17.8 Yes 239+08 42" 70.0 75.0 Yes 245+42 48" 90.3 104.5 Yes 260+41 24" 5.8 17.8 Yes

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293+00 24" 4.2 17.8 Yes 330+00 24" 7.4 17.8 Yes 373+45 24" 1.0 17.8 Yes 380+49 24" 0.5 17.8 Yes

4.3 FLOODPLAIN REGULATIONS COMPLIANCE

As discussed in Section 3.2 the Spring Creek culvert at station 185+11 is located in FEMA Zone A. Both FEMA and Uintah County regulations allow a maximum increase in 100-year base flood elevations (BFE) of 1 foot in Zone A areas.

A comparison of existing and proposed 100-year base flood elevations at Spring Creek is shown in Table

13. The results show that the proposed culvert will reduce base flood elevations at Spring Creek.

Therefore, both FEMA and Uintah County floodplain management criteria are satisfied.

Table 13: Proposed vs Existing 100-Year Base Flood Elevations

Condition 100-year Water Surface Elevation (ft) Existing 100-year 6,032.1

Proposed 100-year 6,029.7 Difference (Proposed – Existing) -2.4

5 RECOMMENDATIONS

The culvert recommendations for existing culvert locations are shown in Table 14. The culvert recommendations for added locations are shown in Table 15. See project plans for additional details of the culvert locations.

Table 14: Summary of Culvert Recommendations – Existing Culvert Locations

Station Existing Culvert

Proposed Culvert Recommendation

85+15 18" CMP 18" Do not disturb existing culvert 151+01 24" CMP (2) 30" Replace culvert, add end sections, outlet protection (Class 3) 163+95 18" CMP 18" Do not disturb existing side culvert 170+81 24" CMP (2) 30" Replace culvert, add end sections, outlet protection (Class 3) 185+11 60" CMP (2) 72” Replace culvert, add headwall, outlet protection (Class 4) 207+95 30" CMP 30" Do not disturb existing culvert, add inlet headwall 217+39 30" CMP 24" Replace culvert, add end sections, outlet protection 256+16 18" CMP 18" Do not disturb existing culvert 276+83 36" CMP (2) 48” Replace culvert, add headwall, outlet protection (Class 4)

Page 11 UT2500(1) Taylor Mountain Road - Hydraulic Report

Table 15: Summary of Culvert Recommendations – Added Culvert Locations

STA Proposed Culvert Recommendation 62+87 24" New culvert, add end sections, outlet protection (Class 2) 95+32 24" New culvert, add end sections, outlet protection (Class 2)

141+17 30" New culvert, add end sections, outlet protection (Class 3) 156+73 24" New culvert, add end sections, outlet protection (Class 2) 202+65 24" New culvert, add end sections, outlet protection (Class 2) 205+35 24" New culvert, add end sections, outlet protection (Class 2) 222+36 24" New culvert, add end sections, outlet protection (Class 2) 235+07 24" New culvert, add end sections, outlet protection (Class 2) 239+08 42" New culvert, add end sections, outlet protection (Class4) 245+42 48" New culvert, add end sections, outlet protection (Class 4) 260+41 24" New culvert, add end sections, outlet protection (Class 2) 293+00 24" New culvert, add end sections, outlet protection (Class 2) 330+00 24" New culvert, add end sections, outlet protection (Class 2) 373+45 24" New culvert, add end sections, outlet protection (Class 2) 380+49 24" New culvert, add end sections, outlet protection (Class 2)

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6 REFERENCES

Bonnin, Geoffrey M., Deborah Martin, Bingzhang Lin, Tye Parzybok, Michael Yekta, and David Riley. 2011.

"Precipitation-Frequency Atlas of the United States, Semiarid Southwest (Arizona, Southeast California, Nevada, New Mexico, Utah)." NOAA Atlas 14, Volume 1, National Oceanic and Atmospheric Administration , Silver Springs, MD.

Federal Highway Administration. 2017. HY-8 Culvert Analysis Program. Version 7.50.

Federal Highway Administration. 2002. Hydraulic Design Series No. 2, Second Edition, FHWA -NHI-02-001.

Washington, DC: Federal Highway Administration.

Federal Lands Highway. 2012. "Project Development and Design Manual, Chapter 7 Hydrology and Hydraulics." https://flh.fhwa.dot.gov/resources/design/pddm/.

Kenney, Terry A., Chris D. Wilkowske, and Shane J. Wright. 2008. "Methods for Estimating Magnitude and Frequency of Peak Flows for Natural Streams in Utah." Scientific Investigations Report 2007-5158, U.S. Geological Survey. https://pubs.usgs.gov/sir/2007/5158/.

Multi-Resolution Land Characteristics Consortium . 2018. National Land Cover Database 2011 (NLCD 2011). Multi-Resolution Land Characteristics Consortium (MRLC).

https://data.nal.usda.gov/dataset/national-land-cover-database-2011-nlcd-2011.

National Oceanic and Atmospheric Administration. 2011. Precipitation Frequency Data Server (PFDS).

Silver Springs, MD. Accessed April 2019. https://hdsc.nws.noaa.gov/hdsc/pfds/index.html.

Natural Resources Conservation Service. 1997. "National Engineering Handbook, Part 630 Hydrology."

Washington, DC. https://directives.sc.egov.usda.gov/viewerFS.aspx?hid=21422.

Natural Resources Conservation Service. 2015. Soil Survey Geographic (SSURGO) database. Fort Worth, TX. Accessed April 2019. http://websoilsurvey.nrcs.usda.gov.

U.S. Army Corps of Engineers. 2017. HEC-HMS, Hydrologic Engineering Center Hydrologic Modeling System. Version 4.2.1. Davis, CA.

U.S. Geological Survey. 2018. The National Map. Accessed March 2019.

https://viewer.nationalmap.gov/advanced-viewer/.

Utah Department of Transportation. 2018. "Drainage Manual of Instruction."

https://www.udot.utah.gov/main/f?p=100:pg:0:::1:T,V:5107.

UT2500(1) Taylor Mountain Road - Hydraulic Report

Appendix A – Hydrologic Analyses

Sources: Esri, HERE, Garmin, Intermap, increment P Corp., GEBCO, USGS, FAO, NPS, NRCAN, GeoBase, IGN, Kadaster NL, Ordnance Survey, Esri Japan, METI, Esri China (Hong Kong), swisstopo, © OpenStreetMap contributors, and the GIS User Community

²0 1 20.5 Miles

Project: UT FLAP 2500(1) Taylor Mountain Road Map Title: Basin Delineation

Date: 2/13/2020 Legend

Basins

Main Flow Path

Begin Project

End Project

USGS The National Map: Orthoimagery. Data refreshed April, 2019.

National Flood Hazard Layer FIRMette

0 500 1,000 1,500 2,000250 Feet

Ü

9°

'36

.63 "W

40°32'53.48"N

109°34'59.17"W

40°32'26.14"N

SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT

SPECIAL FLOOD

HAZARD AREAS

Without Base Flood Elevation (BFE) Zone A, V, A99

With BFE or Depth Zone AE, AO, AH, VE, AR Regulatory Floodway

0.2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mile Zone X Future Conditions 1% Annual Chance Flood Hazard Zone X Area with Reduced Flood Risk due to Levee. See Notes. Zone X Area with Flood Risk due to Levee Zone D

NO SCREEN Area of Minimal Flood Hazard Zone X

Area of Undetermined Flood Hazard Zone D

Channel, Culvert, or Storm Sewer Levee, Dike, or Floodwall

Cross Sections with 1% Annual Chance

17.5 Water Surface Elevation

Coastal Transect

Coastal Transect Baseline Profile Baseline Hydrographic Feature

Base Flood Elevation Line (BFE)

Effective LOMRs

Limit of Study Jurisdiction Boundary

Digital Data Available No Digital Data Available Unmapped

This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below.

The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on 2/12/2020 at 1:31:31 PM and does not reflect changes or amendments subsequent to this date and time. The NFHL and effective information may change or become superseded by new data over time.

This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for regulatory purposes.

Legend

OTHER AREAS OF

FLOOD HAZARD

OTHER AREAS

GENERAL

STRUCTURES

OTHER

FEATURES

MAP PANELS

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1/14/2020 Precipitation Frequency Data Server https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=40.5793&lon=-109.5847&data=depth&units=english&series=pds 1/4

NOAA Atlas 14, Volume 1, Version 5 Location name: Vernal, Utah, USA*

Latitude: 40.5793°, Longitude: -109.5847° Elevation: 6551.66 ft**

* source: ESRI Maps ** source: USGS

POINT PRECIPITATION FREQUENCY ESTIMATES

Sanja Perica, Sarah Dietz, Sarah Heim, Lillian Hiner, Kazungu Maitaria, Deborah Martin, Sandra Pavlovic, Ishani Roy, Carl Trypaluk, Dale Unruh, Fenglin Yan, Michael Yekta, Tan Zhao, Geoffrey

Bonnin, Daniel Brewer, Li-Chuan Chen, Tye Parzybok, John Yarchoan

NOAA, National Weather Service, Silver Spring, Maryland

PF_tabular | PF_graphical | Maps_&_aerials

PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1

Duration Average recurrence interval (years)

1 2 5 10 25 50 100 200 500 1000

5-min 0.120 (0.104‑0.142)

0.155 (0.134‑0.185)

0.213 (0.183‑0.252)

0.265 (0.226‑0.313)

0.347 (0.288‑0.412)

0.422 (0.342‑0.503)

0.508 (0.401‑0.612)

0.609 (0.463‑0.745)

0.769 (0.556‑0.960)

0.915 (0.637‑1.17)

10-min 0.183 (0.158‑0.215)

0.236 (0.203‑0.281)

0.323 (0.278‑0.384)

0.403 (0.343‑0.476)

0.528 (0.438‑0.627)

0.642 (0.520‑0.766)

0.773 (0.609‑0.931)

0.927 (0.706‑1.13)

1.17 (0.846‑1.46)

1.39 (0.969‑1.78)

15-min 0.226 (0.195‑0.267)

0.292 (0.252‑0.348)

0.401 (0.344‑0.476)

0.500 (0.425‑0.591)

0.655 (0.543‑0.777)

0.795 (0.645‑0.949)

0.958 (0.755‑1.16)

1.15 (0.875‑1.41)

1.45 (1.05‑1.81)

1.73 (1.20‑2.20)

30-min 0.304 (0.263‑0.360)

0.393 (0.339‑0.469)

0.540 (0.464‑0.641)

0.673 (0.573‑0.796)

0.882 (0.732‑1.05)

1.07 (0.868‑1.28)

1.29 (1.02‑1.55)

1.55 (1.18‑1.89)

1.95 (1.41‑2.44)

2.33 (1.62‑2.97)

60-min 0.377 (0.326‑0.445)

0.487 (0.420‑0.580)

0.668 (0.574‑0.793)

0.833 (0.709‑0.984)

1.09 (0.906‑1.30)

1.33 (1.08‑1.58)

1.60 (1.26‑1.92)

1.91 (1.46‑2.34)

2.42 (1.75‑3.02)

2.88 (2.00‑3.67)

2-hr 0.459 (0.401‑0.533)

0.578 (0.506‑0.673)

0.774 (0.672‑0.899)

0.951 (0.817‑1.10)

1.24 (1.04‑1.44)

1.50 (1.23‑1.75)

1.81 (1.44‑2.14)

2.17 (1.67‑2.61)

2.77 (2.02‑3.41)

3.32 (2.32‑4.17)

3-hr 0.516 (0.454‑0.596)

0.650 (0.573‑0.748)

0.850 (0.744‑0.981)

1.03 (0.895‑1.19)

1.32 (1.12‑1.52)

1.57 (1.30‑1.82)

1.86 (1.51‑2.19)

2.21 (1.74‑2.65)

2.80 (2.10‑3.42)

3.34 (2.41‑4.19)

6-hr 0.657 (0.583‑0.745)

0.822 (0.732‑0.935)

1.04 (0.922‑1.18)

1.23 (1.09‑1.40)

1.52 (1.31‑1.72)

1.74 (1.49‑1.99)

2.01 (1.68‑2.32)

2.34 (1.91‑2.72)

2.90 (2.29‑3.45)

3.41 (2.62‑4.23)

12-hr 0.805 (0.726‑0.902)

1.00 (0.902‑1.12)

1.25 (1.12‑1.40)

1.46 (1.30‑1.64)

1.77 (1.55‑2.00)

2.03 (1.75‑2.30)

2.31 (1.96‑2.65)

2.61 (2.17‑3.03)

3.14 (2.53‑3.73)

3.64 (2.85‑4.39)

24-hr 1.01 (0.927‑1.12)

1.26 (1.15‑1.39)

1.57 (1.43‑1.73)

1.84 (1.67‑2.01)

2.21 (1.99‑2.42)

2.51 (2.26‑2.75)

2.83 (2.53‑3.10)

3.17 (2.81‑3.47)

3.65 (3.20‑4.01)

4.04 (3.51‑4.45)

2-day 1.15 (1.05‑1.26)

1.43 (1.31‑1.58)

1.78 (1.63‑1.96)

2.07 (1.89‑2.28)

2.48 (2.25‑2.72)

2.81 (2.53‑3.07)

3.15 (2.82‑3.45)

3.50 (3.12‑3.85)

4.01 (3.52‑4.41)

4.40 (3.84‑4.86)

3-day 1.25 (1.14‑1.37)

1.56 (1.42‑1.71)

1.93 (1.76‑2.11)

2.24 (2.04‑2.45)

2.67 (2.43‑2.92)

3.01 (2.72‑3.29)

3.37 (3.03‑3.68)

3.74 (3.34‑4.09)

4.26 (3.76‑4.66)

4.66 (4.09‑5.12)

4-day 1.35 (1.23‑1.47)

1.68 (1.53‑1.83)

2.08 (1.90‑2.27)

2.41 (2.20‑2.63)

2.86 (2.61‑3.12)

3.22 (2.92‑3.50)

3.60 (3.24‑3.91)

3.98 (3.56‑4.33)

4.51 (4.00‑4.92)

4.92 (4.33‑5.38)

7-day 1.60 (1.48‑1.75)

1.99 (1.83‑2.17)

2.47 (2.27‑2.69)

2.86 (2.62‑3.11)

3.40 (3.11‑3.69)

3.83 (3.48‑4.15)

4.28 (3.87‑4.64)

4.74 (4.26‑5.15)

5.37 (4.78‑5.85)

5.87 (5.18‑6.41)

10-day 1.82 (1.67‑1.98)

2.26 (2.08‑2.47)

2.79 (2.56‑3.05)

3.22 (2.95‑3.51)

3.80 (3.47‑4.13)

4.25 (3.86‑4.62)

4.71 (4.26‑5.12)

5.17 (4.66‑5.64)

5.80 (5.18‑6.34)

6.28 (5.58‑6.89)

20-day 2.39 (2.20‑2.60)

2.97 (2.74‑3.24)

3.65 (3.35‑3.96)

4.17 (3.83‑4.53)

4.86 (4.46‑5.27)

5.39 (4.92‑5.85)

5.92 (5.38‑6.42)

6.44 (5.84‑7.00)

7.13 (6.42‑7.78)

7.65 (6.84‑8.37)

30-day 2.91 (2.69‑3.14)

3.61 (3.34‑3.91)

4.38 (4.05‑4.74)

4.98 (4.59‑5.38)

5.75 (5.29‑6.22)

6.32 (5.80‑6.83)

6.89 (6.30‑7.45)

7.44 (6.78‑8.06)

8.15 (7.40‑8.84)

8.67 (7.84‑9.43)

45-day 3.60 (3.34‑3.89)

4.47 (4.15‑4.83)

5.41 (5.01‑5.84)

6.12 (5.65‑6.61)

7.02 (6.48‑7.59)

7.69 (7.08‑8.31)

8.35 (7.66‑9.03)

8.98 (8.22‑9.73)

9.79 (8.91‑10.6)

10.4 (9.40‑11.3)

60-day 4.26 (3.95‑4.59)

5.29 (4.91‑5.69)

6.34 (5.88‑6.82)

7.11 (6.58‑7.65)

8.07 (7.46‑8.68)

8.76 (8.07‑9.41)

9.41 (8.65‑10.1)

10.0 (9.19‑10.8)

10.8 (9.84‑11.6)

11.3 (10.3‑12.2)

1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).

Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.

Please refer to NOAA Atlas 14 document for more information.

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Large scale map

Large scale aerial

3km

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US Department of Commerce National Oceanic and Atmospheric Administration

National Weather Service National Water Center

1325 East West Highway Silver Spring, MD 20910

Questions?: HDSC.Questions@noaa.gov

Disclaimer

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60mi https://www.commerce.gov/ http://www.noaa.gov/ http://www.nws.noaa.gov/ http://www.nws.noaa.gov/oh/ mailto:HDSC.Questions@noaa.gov http://www.nws.noaa.gov/disclaimer.html https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=40.5793&lon=-109.5847&data=intensity&units=english&series=pds 1/4

NOAA Atlas 14, Volume 1, Version 5 Location name: Vernal, Utah, USA*

Latitude: 40.5793°, Longitude: -109.5847° Elevation: m/ft**

* source: ESRI Maps

** source: USGS

POINT PRECIPITATION FREQUENCY ESTIMATES

Sanja Perica, Sarah Dietz, Sarah Heim, Lillian Hiner, Kazungu Maitaria, Deborah Martin, Sandra Pavlovic, Ishani Roy, Carl Trypaluk, Dale Unruh, Fenglin Yan, Michael Yekta, Tan Zhao, Geoffrey

Bonnin, Daniel Brewer, Li-Chuan Chen, Tye Parzybok, John Yarchoan

NOAA, National Weather Service, Silver Spring, Maryland

PF_tabular | PF_graphical | Maps_&_aerials

PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches/hour)1

Duration Average recurrence interval (years)

1 2 5 10 25 50 100 200 500 1000

5-min 1.44 (1.25‑1.70)

1.86 (1.61‑2.22)

2.56 (2.20‑3.02)

3.18 (2.71‑3.76)

4.16 (3.46‑4.94)

5.06 (4.10‑6.04)

6.10 (4.81‑7.34)

7.31 (5.56‑8.94)

9.23 (6.67‑11.5)

11.0 (7.64‑14.0)

10-min 1.10 (0.948‑1.29)

1.42 (1.22‑1.69)

1.94 (1.67‑2.30)

2.42 (2.06‑2.86)

3.17 (2.63‑3.76)

3.85 (3.12‑4.60)

4.64 (3.65‑5.59)

5.56 (4.24‑6.80)

7.03 (5.08‑8.77)

8.36 (5.81‑10.7)

15-min 0.904 (0.780‑1.07)

1.17 (1.01‑1.39)

1.60 (1.38‑1.90)

2.00 (1.70‑2.36)

2.62 (2.17‑3.11)

3.18 (2.58‑3.80)

3.83 (3.02‑4.62)

4.59 (3.50‑5.62)

5.80 (4.20‑7.25)

6.91 (4.80‑8.81)

30-min 0.608 (0.526‑0.720)

0.786 (0.678‑0.938)

1.08 (0.928‑1.28)

1.35 (1.15‑1.59)

1.76 (1.46‑2.09)

2.14 (1.74‑2.56)

2.58 (2.03‑3.11)

3.09 (2.36‑3.78)

3.91 (2.83‑4.88)

4.65 (3.23‑5.93)

60-min 0.377 (0.326‑0.445)

0.487 (0.420‑0.580)

0.668 (0.574‑0.793)

0.833 (0.709‑0.984)

1.09 (0.906‑1.30)

1.33 (1.08‑1.58)

1.60 (1.26‑1.92)

1.91 (1.46‑2.34)

2.42 (1.75‑3.02)

2.88 (2.00‑3.67)

2-hr 0.230 (0.200‑0.266)

0.289 (0.253‑0.336)

0.387 (0.336‑0.450)

0.476 (0.408‑0.552)

0.618 (0.519‑0.719)

0.749 (0.613‑0.876)

0.904 (0.719‑1.07)

1.09 (0.834‑1.31)

1.39 (1.01‑1.71)

1.66 (1.16‑2.08)

3-hr 0.172 (0.151‑0.198)

0.216 (0.191‑0.249)

0.283 (0.248‑0.327)

0.344 (0.298‑0.396)

0.438 (0.373‑0.507)

0.521 (0.433‑0.606)

0.621 (0.502‑0.731)

0.737 (0.578‑0.881)

0.932 (0.700‑1.14)

1.11 (0.803‑1.39)

6-hr 0.110 (0.097‑0.124)

0.137 (0.122‑0.156)

0.174 (0.154‑0.198)

0.206 (0.181‑0.234)

0.253 (0.219‑0.288)

0.291 (0.248‑0.332)

0.336 (0.281‑0.387)

0.390 (0.319‑0.455)

0.484 (0.383‑0.575)

0.570 (0.438‑0.706)

12-hr 0.067 (0.060‑0.075)

0.083 (0.075‑0.093)

0.104 (0.093‑0.116)

0.121 (0.108‑0.136)

0.147 (0.129‑0.166)

0.168 (0.145‑0.191)

0.192 (0.162‑0.220)

0.216 (0.180‑0.251)

0.261 (0.210‑0.310)

0.302 (0.236‑0.365)

24-hr 0.042 (0.039‑0.047)

0.053 (0.048‑0.058)

0.065 (0.060‑0.072)

0.076 (0.070‑0.084)

0.092 (0.083‑0.101)

0.104 (0.094‑0.114)

0.118 (0.105‑0.129)

0.132 (0.117‑0.145)

0.152 (0.133‑0.167)

0.168 (0.146‑0.185)

2-day 0.024 (0.022‑0.026)

0.030 (0.027‑0.033)

0.037 (0.034‑0.041)

0.043 (0.039‑0.047)

0.052 (0.047‑0.057)

0.058 (0.053‑0.064)

0.066 (0.059‑0.072)

0.073 (0.065‑0.080)

0.083 (0.073‑0.092)

0.092 (0.080‑0.101)

3-day 0.017 (0.016‑0.019)

0.022 (0.020‑0.024)

0.027 (0.025‑0.029)

0.031 (0.028‑0.034)

0.037 (0.034‑0.041)

0.042 (0.038‑0.046)

0.047 (0.042‑0.051)

0.052 (0.046‑0.057)

0.059 (0.052‑0.065)

0.065 (0.057‑0.071)

4-day 0.014 (0.013‑0.015)

0.017 (0.016‑0.019)

0.022 (0.020‑0.024)

0.025 (0.023‑0.027)

0.030 (0.027‑0.032)

0.034 (0.030‑0.036)

0.037 (0.034‑0.041)

0.041 (0.037‑0.045)

0.047 (0.042‑0.051)

0.051 (0.045‑0.056)

7-day 0.010 (0.009‑0.010)

0.012 (0.011‑0.013)

0.015 (0.013‑0.016)

0.017 (0.016‑0.018)

0.020 (0.018‑0.022)

0.023 (0.021‑0.025)

0.025 (0.023‑0.028)

0.028 (0.025‑0.031)

0.032 (0.028‑0.035)

0.035 (0.031‑0.038)

10-day 0.008 (0.007‑0.008)

0.009 (0.009‑0.010)

0.012 (0.011‑0.013)

0.013 (0.012‑0.015)

0.016 (0.014‑0.017)

0.018 (0.016‑0.019)

0.020 (0.018‑0.021)

0.022 (0.019‑0.024)

0.024 (0.022‑0.026)

0.026 (0.023‑0.029)

20-day 0.005 (0.005‑0.005)

0.006 (0.006‑0.007)

0.008 (0.007‑0.008)

0.009 (0.008‑0.009)

0.010 (0.009‑0.011)

0.011 (0.010‑0.012)

0.012 (0.011‑0.013)

0.013 (0.012‑0.015)

0.015 (0.013‑0.016)

0.016 (0.014‑0.017)

30-day 0.004 (0.004‑0.004)

0.005 (0.005‑0.005)

0.006 (0.006‑0.007)

0.007 (0.006‑0.007)

0.008 (0.007‑0.009)

0.009 (0.008‑0.009)

0.010 (0.009‑0.010)

0.010 (0.009‑0.011)

0.011 (0.010‑0.012)

0.012 (0.011‑0.013)

45-day 0.003 (0.003‑0.004)

0.004 (0.004‑0.004)

0.005 (0.005‑0.005)

0.006 (0.005‑0.006)

0.007 (0.006‑0.007)

0.007 (0.007‑0.008)

0.008 (0.007‑0.008)

0.008 (0.008‑0.009)

0.009 (0.008‑0.010)

0.010 (0.009‑0.010)

60-day 0.003 (0.003‑0.003)

0.004 (0.003‑0.004)

0.004 (0.004‑0.005)

0.005 (0.005‑0.005)

0.006 (0.005‑0.006)

0.006 (0.006‑0.007)

0.007 (0.006‑0.007)

0.007 (0.006‑0.007)

0.007 (0.007‑0.008)

0.008 (0.007‑0.009)

1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).

Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.

Please refer to NOAA Atlas 14 document for more information.

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US Department of Commerce National Oceanic and Atmospheric Administration

National Weather Service National Water Center

1325 East West Highway Silver Spring, MD 20910

Questions?: HDSC.Questions@noaa.gov

Disclaimer

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HEC-HMS Information

Subbasin Area:

NRCS Curve Number:

Lag Time:

2-Year 24-Hour Results

5-Year 24-Hour Results

10-Year 24-Hour Results

25-Year 24-Hour Results

50-Year 24-Hour Results

100-Year 24-Hour Results

500-Year 24-Hour Results

UT2500(1) Taylor Mountain Road - Hydraulic Report

Appendix B - Hydraulic Analyses

Existing Minor Culverts HY-8 Culvert Analysis Report

Table 1 - Summary of Culvert Flows at Crossing: 85+15 EX

Headwater Elevation (ft) Discharge Names Total Discharge

(cfs) Culvert 1

Discharge (cfs) Roadway

Discharge (cfs) Iterations

6073.79 25 year 7.90 7.90 0.00 1

6074.29 50 year 9.60 9.60 0.00 1

6075.01 100 year 11.60 11.60 0.00 1

6085.40 Overtopping 20.51 20.51 0.00 Overtopping

Table 2 - Culvert Summary Table: Culvert 1

Discharg e

Names Total

Discharg e (cfs)

Culvert Discharg e (cfs) Headwat er Elevatio n (ft)

Inlet Control Depth

(ft)

Outlet Control Depth

(ft) Flow Type

Normal Depth

(ft) Critical Depth

(ft) Outlet Depth

(ft) Tailwate r Depth

(ft) Outlet

Velocity (ft/s)

Tailwate r

Velocity (ft/s) year 7.90 7.90 6073.79 1.994 0.0* 5-S2n 0.735 1.085 0.749 0.200 8.665 3.880 year 9.60 9.60 6074.29 2.486 0.0* 5-S2n 0.827 1.195 0.827 0.225 9.303 4.182 year 11.60 11.60 6075.01 3.210 0.0* 5-S2n 0.937 1.297 0.937 0.252 9.693 4.499

* Full Flow Headwater elevation is below inlet invert.

Straight Culvert

Inlet Elevation (invert): 6071.80 ft, Outlet Elevation (invert): 6060.50 ft

Culvert Length: 150.43 ft, Culvert Slope: 0.0753

Site Data - Culvert 1 Site Data Option: Culvert Invert Data Inlet Station: 0.00 ft Inlet Elevation: 6071.80 ft Outlet Station: 150.00 ft Outlet Elevation: 6060.50 ft Number of Barrels: 1

Culvert Data Summary - Culvert 1 Barrel Shape: Circular Barrel Diameter: 1.50 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

Table 3 - Downstream Channel Rating Curve (Crossing: 85+15 EX)

Tailwater Channel Data - 85+15 EX Tailwater Channel Option: Trapezoidal Channel Bottom Width: 10.00 ft Side Slope (H:V): 1.00 (_:1) Channel Slope: 0.0750 Channel Manning's n: 0.0350 Channel Invert Elevation: 6060.50 ft

Roadway Data for Crossing: 85+15 EX Roadway Profile Shape: Constant Roadway Elevation Crest Length: 100.00 ft Crest Elevation: 6085.40 ft Roadway Surface: Paved Roadway Top Width: 24.00 ft

Flow (cfs) Water Surface Elev (ft) Depth (ft) Velocity (ft/s) Shear (psf) Froude Number

7.90 6060.70 0.20 3.88 0.93 1.55

9.60 6060.72 0.22 4.18 1.05 1.57

11.60 6060.75 0.25 4.50 1.18 1.60

Table 4 - Summary of Culvert Flows at Crossing: 151+01 EX

(cfs) Culvert 1

Discharge (cfs) Roadway

Discharge (cfs) Iterations

5992.51 25 year 47.60 19.64 27.90 6

5992.55 50 year 57.80 19.82 37.85 3

5992.60 100 year 69.60 19.98 49.57 3

5992.30 Overtopping 18.97 18.97 0.00 Overtopping

Table 5 - Culvert Summary Table: Culvert 1

Straight Culvert

Inlet Elevation (invert):

5988.20 ft, Outlet

Elevation (invert): 5988.00 ft

Culvert Length: 60.60 ft, Culvert Slope: 0.0033

Site Data - Culvert 1 Site Data Option: Culvert Invert Data Inlet Station: 0.00 ft Inlet Elevation: 5988.20 ft Outlet Station: 60.60 ft Outlet Elevation: 5988.00 ft Number of Barrels: 1

Culvert Data Summary - Culvert 1 Barrel Shape: Circular Barrel Diameter: 2.00 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

Discharg e

Names Total

Discharg e (cfs)

Culvert Discharg e (cfs) Headwat er Elevatio n (ft)

Inlet Control Depth

(ft)

Outlet Control Depth

(ft) Flow Type

Normal Depth

(ft) Critical Depth

(ft) Outlet Depth

(ft) Tailwate r Depth

(ft) Outlet

Velocity (ft/s)

Tailwate r

Velocity (ft/s) year 47.60 19.64 5992.51 3.374 4.306 7-M2 c 2.000 1.591 1.591 1.496 7.330 2.767 year 57.80 19.82 5992.55 3.410 4.357 7-M2t 2.000 1.597 1.679 1.679 7.039 2.949 year 69.60 19.98 5992.60 3.445 4.495 7-M2t 2.000 1.604 1.873 1.873 6.535 3.130

Table 6 - Downstream Channel Rating Curve (Crossing: 151+01 EX)

Tailwater Channel Data - 151+01 EX Tailwater Channel Option: Trapezoidal Channel Bottom Width: 10.00 ft Side Slope (H:V): 1.00 (_:1) Channel Slope: 0.0033 Channel Manning's n: 0.0350 Channel Invert Elevation: 5988.00 ft

Roadway Data for Crossing: 151+01 EX Roadway Profile Shape: Constant Roadway Elevation Crest Length: 100.00 ft Crest Elevation: 5992.30 ft Roadway Surface: Paved Roadway Top Width: 24.00 ft

Flow (cfs) Water Surface Elev (ft) Depth (ft) Velocity (ft/s) Shear (psf) Froude Number

47.60 5989.50 1.50 2.77 0.31 0.42

57.80 5989.68 1.68 2.95 0.35 0.43

69.60 5989.87 1.87 3.13 0.39 0.43

Table 7 - Summary of Culvert Flows at Crossing: 163+95 EX

(cfs) Culvert 1

Discharge (cfs) Roadway

Discharge (cfs) Iterations

6009.14 10 year 7.30 5.32 1.95 13

6009.16 25 year 9.50 5.43 4.05 4

6009.18 50 year 11.60 5.51 6.04 3

6009.19 100 year 14.00 5.60 8.38 3

6009.10 Overtopping 5.14 5.14 0.00 Overtopping

Table 8 - Culvert Summary Table: Culvert 1

Straight Culvert

Inlet Elevation (invert):

6007.70 ft, Outlet

Elevation (invert): 6006.20 ft

Culvert Length: 41.23 ft, Culvert Slope: 0.0364

Site Data - Culvert 1 Site Data Option: Culvert Invert Data Inlet Station: 0.00 ft Inlet Elevation: 6007.70 ft Outlet Station: 41.20 ft Outlet Elevation: 6006.20 ft Number of Barrels: 1

Culvert Data Summary - Culvert 1 Barrel Shape: Circular Barrel Diameter: 1.50 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

Discharg e

Names Total

Discharg e (cfs)

Culvert Discharg e (cfs) Headwat er Elevatio n (ft)

Inlet Control Depth

(ft)

Outlet Control Depth

(ft) Flow Type

Normal Depth

(ft) Critical Depth

(ft) Outlet Depth

(ft) Tailwate r Depth

(ft) Outlet

Velocity (ft/s)

Tailwate r

Velocity (ft/s) year 7.30 5.32 6009.14 1.436 0.011 1-S2n 0.721 0.886 0.721 0.237 6.123 3.005 year 9.50 5.43 6009.16 1.459 0.046 1-S2n 0.730 0.895 0.730 0.278 6.154 3.323 year 11.60 5.51 6009.18 1.476 0.074 1-S2n 0.737 0.902 0.737 0.314 6.178 3.586 year 14.00 5.60 6009.19 1.494 0.103 1-S2n 0.743 0.909 0.743 0.351 6.202 3.852

Table 9 - Downstream Channel Rating Curve (Crossing: 163+95 EX)

Tailwater Channel Data - 163+95 EX Tailwater Channel Option: Trapezoidal Channel Bottom Width: 10.00 ft Side Slope (H:V): 1.00 (_:1) Channel Slope: 0.0360 Channel Manning's n: 0.0350 Channel Invert Elevation: 6006.20 ft

Roadway Data for Crossing: 163+95 EX Roadway Profile Shape: Constant Roadway Elevation Crest Length: 100.00 ft Crest Elevation: 6009.10 ft Roadway Surface: Paved Roadway Top Width: 24.00 ft

Flow (cfs) Water Surface Elev (ft) Depth (ft) Velocity (ft/s) Shear (psf) Froude Number

7.30 6006.44 0.24 3.01 0.53 1.10

9.50 6006.48 0.28 3.32 0.62 1.13

11.60 6006.51 0.31 3.59 0.70 1.15

14.00 6006.55 0.35 3.85 0.79 1.16

Table 10 - Summary of Culvert Flows at Crossing: 170+81 EX

(cfs) Culvert 1

Discharge (cfs) Roadway

Discharge (cfs) Iterations

6020.64 25 year 35.40 19.56 15.71 9

6020.68 50 year 43.00 19.76 23.05 3

6020.73 100 year 51.80 19.96 31.75 3

6020.50 Overtopping 18.86 18.86 0.00 Overtopping

Table 11 - Culvert Summary Table: Culvert 1

Straight Culvert

Inlet Elevation (invert):

6017.30 ft, Outlet

Elevation (invert): 6016.10 ft

Culvert Length: 60.71 ft, Culvert Slope: 0.0198

Site Data - Culvert 1 Site Data Option: Culvert Invert Data Inlet Station: 0.00 ft Inlet Elevation: 6017.30 ft Outlet Station: 60.70 ft Outlet Elevation: 6016.10 ft Number of Barrels: 1

Culvert Data Summary - Culvert 1 Barrel Shape: Circular Barrel Diameter: 2.00 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

Discharg e

Names Total

Discharg e (cfs)

Culvert Discharg e (cfs) Headwat er Elevatio n (ft)

Inlet Control Depth

(ft)

Outlet Control Depth

(ft) Flow Type

Normal Depth

(ft) Critical Depth

(ft) Outlet Depth

(ft) Tailwate r Depth

(ft) Outlet

Velocity (ft/s)

Tailwate r

Velocity (ft/s) year 35.40 19.56 6020.64 3.341 3.153 7-M2 c 2.000 1.588 1.588 0.732 7.314 4.508 year 43.00 19.76 6020.68 3.382 3.227 7-M2 c 2.000 1.595 1.595 0.822 7.354 4.832 year 51.80 19.96 6020.73 3.425 3.304 7-M2 c 2.000 1.603 1.603 0.919 7.397 5.160

Table 12 - Downstream Channel Rating Curve (Crossing: 170+81 EX)

Tailwater Channel Data - 170+81 EX Tailwater Channel Option: Trapezoidal Channel Bottom Width: 10.00 ft Side Slope (H:V): 1.00 (_:1) Channel Slope: 0.0200 Channel Manning's n: 0.0350 Channel Invert Elevation: 6016.10 ft

Roadway Data for Crossing: 170+81 EX Roadway Profile Shape: Constant Roadway Elevation Crest Length: 100.00 ft Crest Elevation: 6020.50 ft Roadway Surface: Paved Roadway Top Width: 24.00 ft

Flow (cfs) Water Surface Elev (ft) Depth (ft) Velocity (ft/s) Shear (psf) Froude Number

35.40 6016.83 0.73 4.51 0.91 0.96

43.00 6016.92 0.82 4.83 1.03 0.97

51.80 6017.02 0.92 5.16 1.15 0.99

Table 13 - Summary of Culvert Flows at Crossing: 207+95 EX

(cfs) Culvert 1

Discharge (cfs) Roadway

Discharge (cfs) Iterations

6108.31 25 year 28.60 28.60 0.00 1

6109.14 50 year 34.70 34.70 0.00 1

6109.75 100 year 41.80 38.49 3.13 15

6109.70 Overtopping 38.20 38.20 0.00 Overtopping

Table 14 - Culvert Summary Table: Culvert 1

Straight Culvert

Inlet Elevation (invert):

6104.90 ft, Outlet

Elevation (invert): 6103.40 ft

Culvert Length: 48.52 ft, Culvert Slope: 0.0309

Site Data - Culvert 1 Site Data Option: Culvert Invert Data Inlet Station: 0.00 ft Inlet Elevation: 6104.90 ft Outlet Station: 48.50 ft Outlet Elevation: 6103.40 ft Number of Barrels: 1

Culvert Data Summary - Culvert 1 Barrel Shape: Circular Barrel Diameter: 2.50 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

Discharg e

Names Total

Discharg e (cfs)

Culvert Discharg e (cfs) Headwat er Elevatio n (ft)

Inlet Control Depth

(ft)

Outlet Control Depth

(ft) Flow Type

Normal Depth

(ft) Critical Depth

(ft) Outlet Depth

(ft) Tailwate r Depth

(ft) Outlet

Velocity (ft/s)

Tailwate r

Velocity (ft/s) year 28.60 28.60 6108.31 3.411 2.122 5-S2n 1.546 1.821 1.593 0.564 8.411 4.798 year 34.70 34.70 6109.14 4.240 3.401 5-S2n 1.784 1.999 1.835 0.634 8.742 5.149 year 41.80 38.49 6109.75 4.849 4.059 5-S2n 1.961 2.094 2.015 0.709 8.858 5.507

Table 15 - Downstream Channel Rating Curve (Crossing: 207+95 EX)

Tailwater Channel Data - 207+95 EX Tailwater Channel Option: Trapezoidal Channel Bottom Width: 10.00 ft Side Slope (H:V): 1.00 (_:1)…