NM_FS_220(1)_Romero Creek Bridge_Final Hydraulics Report.pdf

Romero Creek Bridge Gila National Forest US Forest Service Catron County, NM

NM FS 220(1)

Final Hydraulics Report

Federal Highway Administration

Central Federal Lands Highway Division

January 14, 2021

Signature Sheet

Report prepared by: ____________________________________________________ Aaron Estep, P.E., Hydraulics Engineer

Report reviewed by: ____________________________________________________ Luis Calderón, P.E., C.F.M., Hydraulics Engineer

Approved for distribution by: ____________________________________________________ Luis Calderón, P.E., C.F.M., Hydraulics Engineer

Distribution

Electronic:

N:\NM\220(1)\Hydraulics\9_Final‐Report Project Management Project Development, Lead Designer Environmental Protection Geotechnical Design Bridge

Executive Summary

Hydrologic and hydraulic analyses were conducted for the NM FS 220(1) Romero Creek Bridge Project. For this crossing, the 50‐year and 100‐year floods were evaluated as the hydraulic design flood in accordance with Federal Lands Highway (FLH) and U.S. Forest Service (USFS) design criteria, respectively. The peak flow values were estimated using available USGS regression equations for New Mexico, NRCS method rainfall‐runoff modeling conducted using HEC‐HMS, and USGS gage comparisons. The selected method for determining the peak flow values was an area comparison with an inactive gage along Romero Creek.

Based on the drainage area associated with this gage, it was determined to be within the project drainage area and thus most representative of the projects contributing watershed.

Existing and proposed conditions two‐dimensional hydraulic modeling using SRH‐2D was conducted to estimate water surface elevations, depths, and flow velocities at the project site. The USFS uses the 100‐ year flood as the hydraulic design flood, requires a 3‐foot minimum freeboard, and recommends simulating debris blockage in the bridge opening where conditions warrant. For this preliminary evaluation a 30% blockage was assumed.

The proposed structure consists of 45‐ft long bridge opening with a low chord elevation of 8,231.6 feet at the eastern abutment. The bridge has a 1% slope, with deck elevations varying from 8,235.1 to 8,234.6 feet. Based on the results of the hydraulic analyses, the proposed bridge meets the requirements of both

FLH and USFS freeboard criteria as summarized in the following table:

Summary of Bridge Freeboard Results

Design Criteria

Hydraulic Capacity Design

Frequency

Bridge Waterway Width (ft)

Minimum Freeboard

(ft)

Maximum

WSEL 16‐

feet Upstream

(ft)

Proposed Low Chord Elevation

(ft)

Provided Freeboard

(ft)

Meets Design Criteria (Yes/No)

FLH PDDM 50‐year 45 2 8,226.2

8,231.6

5.4 Yes

USFS TSH 100‐year 45 3 8,226.9 4.7 Yes

USFS TSH –

including 30%

Debris Blockage

100‐year 45 3 8,227.1 4.5 Yes i NM FS 220(1) Romero Creek Bridge – Draft 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 Regression Equation Estimates

3.5 USGS Streamflow Gage Analysis

3.6 Rainfall‐Runoff Model Estimates

3.6.1 Precipitation

3.6.2 Basin Parameters

3.7 Recommended Design Flows

4 Hydraulic Analysis

4.1 Topographic Information

4.2 Existing Hydraulic Model Development

4.3 Existing Hydraulic Model Results

4.3.1 Existing Conditions

4.3.2 Existing Conditions with Blockages

4.4 Proposed Hydraulic Model Development

4.5 Proposed Hydraulic Model Results

4.5.1 Proposed Conditions

4.5.2 Proposed Conditions with Blockages

4.6 Hydraulic Model Summary Tables

4.7 Scour Considerations

5 Summary

6 References ii NM FS 220(1) Romero Creek Bridge – Draft Hydraulic Report

Tables Table 1: FLH Hydraulic Design Criteria

Table 2: USFS Bridge Hydraulic Design Criteria

Table 3: Basin Properties

Table 4: Available Peak Streamflow Information

Table 5: StreamStats Peak Flow Estimates Standard Error of Prediction at Project Site

Table 6: Peak Flow Comparison USGS 09442650 (Romero Creek) and Project Site

Table 7: NOAA Atlas 14 24‐Hour Point Precipitation – Basin Centroid

Table 8: Basin Parameters (NRCS Method)

Table 9: HEC‐HMS Peak Discharge Estimates at Project Site

Table 10: Recommended Design Flows

Table 11: Project Land Cover Types and Manning’s Roughness (Existing)

Table 12: 50‐year and 100‐year Existing Conditions Hydraulic Results

Table 13: 50‐year and 100‐year Existing Conditions Freeboard

Table 14: 50‐year and 100‐year Existing Conditions Hydraulic Results – 30% Blockage

Table 15: 50‐year and 100‐year Existing Conditions Freeboard – 30% Blockages

Table 16: 50‐year and 100‐year Proposed Conditions Hydraulic Results

Table 17: 50‐year and 100‐year Proposed Conditions Freeboard

Table 18: 50‐year and 100‐year Proposed Conditions Hydraulic Results – 30% Blockage

Table 19: 50‐year and 100‐year Proposed Conditions Freeboard – 30% Blockages

Table 20: Existing Conditions Hydraulic Model Summary Table

Table 21: Proposed Conditions Hydraulic Model Summary Table

Table 22: Summary of Bridge Freeboard Results

Figures Figure 1: Project Location Map

Figure 2: Drainage Basin Map

Figure 3: Topographic Surface, Elevations in feet referenced to NAVD88

Figure 4: Project Land Cover Types and Manning’s Roughness (Existing)

Figure 5: SRH‐2D Mesh Detail near Bridge (Existing)

Figure 6: Existing Conditions WSEL at Upstream Bridge Face (XS‐1) ‐ Looking Downstream

Figure 7: Existing Conditions WSEL 16 feet Upstream of Bridge (XS‐2) ‐ Looking Downstream

Figure 8: Existing Conditions Water Surface Profile Through Bridge

Figure 9: Project Land Cover Types and Manning’s Roughness (Proposed)

Figure 10: SRH‐2D Mesh Detail near Bridge (Proposed)

Figure 11: Proposed Conditions WSEL at Upstream Bridge Face (XS‐1) ‐ Looking Downstream

Figure 12: Proposed Conditions WSEL 16 feet Upstream of Bridge (XS‐2) ‐ Looking Downstream

Figure 13: Proposed Conditions Water Surface Profile Through Bridge

Appendices Appendix A: Hydrologic Analyses

Appendix B: Existing Hydraulic Analyses

Appendix C: Proposed Hydraulic Analyses

Page 1 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

1 PROJECT BACKGROUND INFORMATION

The Romero Creek Bridge project is located in Catron County, NM within the Gila National Forest. The existing bridge carries National Forest Route 220 over Romero Creek, see Figure 1.

Figure 1: Project Location Map

Page 2 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

2 HYDRAULIC DESIGN CRITERIA

The Federal Lands Highway Project Development and Design Manual (PDDM) (Federal Lands Highway

2012) along with the USFS Transportation Structures Handbook (TSH) (U.S. Forest Service 2014) establishes the hydraulic design criteria. Based on the project scoping summary, National Forest Route

220 is classified as a Forest Service Maintenance Level 3 with an average daily traffic (ADT) of less than

200 vehicles. Based on these parameters the road is classified as low standard for hydraulic design purposes. The applicable FLH design criteria are listed in Table 1. In addition, the USFS criteria for bridge hydraulic capacity is listed in Table 2. The hydraulic capacity and freeboard requirements for the proposed bridge provided in this report were estimated using both FLH and USFS criteria. The USFS references

HEC‐18 (Federal Highway Administration 2009) for scour estimates therefore the scour criteria shown in

Table 1 will be applied to the project.

Table 1: FLH Hydraulic Design Criteria

Road Classification: Low‐Standard Road

Bridges

Design Frequency

Check Frequency Freeboard

50‐year flood

Greater of 100‐year or overtopping flood

Minimum of 2 feet

3.5 feet to 5 feet when woody debris potential is significant 5 feet to 10 feet when ice flow potential is significant

Scour

Design Frequency

Check Frequency Countermeasure Design Frequency

100‐year flood

200‐year flood 200‐year flood

Floodplain Encroachment

FEMA SFHA Involvement Allowable Rise

Project area is unmapped by FEMA and therefore is not a regulated special flood hazard area (SFHA)

Maximum 1‐foot rise in water surface profile over existing conditions

Table 2: USFS Bridge Hydraulic Design Criteria

Bridges

Design Frequency

Check Frequency Freeboard

100‐year flood

Not specified Minimum of 3 feet 30‐50% debris blockage where history or wildfire warrants.

Page 3 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

3 HYDROLOGY

3.1 HYDROLOGIC SETTING

The project is located within the Trout Creek Subwatershed (HUC12: 150400040302). The total contributing drainage area to the bridge is approximately 10.8 square miles. Romero Creek generally flows from west to east from its headwaters near Escudilla Mountain in Arizona to the confluence with

Trout Creek located approximately 1.25 miles downstream of the project site. The contributing drainage basin was delineated using available 10‐meter digital elevation model (DEM) information obtained from the USGS National Map as shown in Figure 2. A summary of general basin properties is shown in Table 3.

Table 3: Basin Properties

Site Drainage Area (mi2)

Mean Basin Elevation (ft)

Mean Basin Slope (%)

Mean Annual Precipitation (in)

Romero Creek Bridge 10.8 8,888 19.2 25.3

Figure 2: Drainage Basin Map

Page 4 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

3.2 FEMA FLOOD INSURANCE STUDY

According to FEMA Map Service Center, the project section of Romero Creek is unmapped in the state of

New Mexico and is therefore not within a special flood hazard area (SFHA). The headwaters of Romero

Creek, located in Arizona, are mapped as Zone D. Zone D designates areas that have the potential for flood hazards but no analysis has been conducted. These areas are also outside of the SFHA. An evaluation of the 100‐year floodplain will be performed as part of this project but no coordination with

FEMA is required.

3.3 AVAILABLE HYDROLOGIC DATA

According to the USGS National Water Information System (NWIS), there are no active USGS peak streamflow stations within the project limits. The closest active USGS station (09442660) is located on Trout Creek near Luna, NM approximately 8 miles downstream of the project site. Although listed as “active”, peak streamflow collection stopped in 2016. An inactive station (09442653) is located approximately 2 miles downstream from the project site. A second inactive station (09442650) is located along Romero Creek and is assumed to be located within the project basin based on the drainage area.

Data from two of these stations (09442660 & 09442650) were included in the development of the USGS regression equations for New Mexico as described in Section 3.4. Table 4 summarizes the station locations and period of record.

Table 4: Available Peak Streamflow Information

USGS

Station

Location Latitude Longitude Drainage Area

Period of Record

Total Peak Streamflow Records

Status

09442660 Trout Creek at Luna, NM

33°50'46" 108°57'06" 31.9 mi2 1954‐

58 Active

09442653 Trout Creek near

Luna, NM 33°53'24" 109°00'38" 27.1 mi2

1968‐

0 Inactive

09442650 Romero Creek near NM/AZ State Line near Luna, NM

33°57'00" 108°59'00" 9.32 mi2 1958‐

19 Inactive

3.4 REGRESSION EQUATION ESTIMATES

The StreamStats web application (U.S. Geological Survey 2016) was used to estimate peak flows for the project sites. The StreamStats application uses the regression equations presented in USGS Report 2008‐

5119 (Waltemeyer 2008). According to the report, the project basin is located in the Southwest Mountain

Flood Region (8) which comprises an area of western New Mexico and a small portion of Arizona generally above an elevation of 7,500 feet. The Region 8 equations relate peak discharge to drainage area.

According to the study the average standard errors of prediction for the equations vary from 43 to 62 percent. The peak flow results and standard error of prediction for the project basin are shown in Table

5.

Page 5 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

Table 5: StreamStats Peak Flow Estimates Standard Error of Prediction at Project Site

Percent Chance

Exceedance

Return Period (year) Peak Flow Estimate

Standard Error of Prediction

(cfs) (%)

50 2 60 55

20 5 142 45

10 10 223 43

4 25 360 45

2 50 490 46

1 100 646 51

0.5 200 8891 ‐‐‐

0.2 500 1,130 62

1 200‐year return period was not provided by StreamStats and was interpolated from the existing data.

3.5 USGS STREAMFLOW GAGE ANALYSIS

As discussed in Section 3.3, there is no active streamflow data near the project to calibrate the peak flow results, however, the inactive Romero Creek USGS gage (09442650) was located along Romero Creek and likely located within the project basin due to its watershed size. These characteristics indicate that this gage would be a reliable source for peak flows at the Romero Creek Bridge. The project site has a drainage area of 10.8 square miles or 116% of the 9.32 square mile area at this gage. Equation 3 in the USGS Report

2008‐5119 (Waltemeyer 2008), and shown below, was used to predict the peak flow at the ungaged project site by comparing the gaged and ungaged areas.

𝑄 𝑄 𝐴 𝐴⁄

Where:

QT(u) = Weighted Peak Flow at Ungaged Site (cfs) QT(g) = Peak Flow at Gaged Site (cfs) Au = Drainage Area at the Ungaged Site (sq. mi.) – 10.8 sq. mi.

Ag = Drainage Area at the Gaged Site (sq. mi.) – 9.32 sq. mi.

x = Exponent of the Drainage Area of the Applicable Regression Equations (provided in USGS Report 2008‐5119 – Table 2)

Based on the calculations using the previous equation, Table 6 shows a theoretical estimate at the project site using the ratio of drainage areas.

Page 6 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

Table 6: Peak Flow Comparison USGS 09442650 (Romero Creek) and Project Site

Return Period (year)

USGS 09442650

Romero Creek Peak Flows

QT(g) (cfs)

Exponent x

Romero Creek Bridge Peak Flows

QT(u) (cfs)

2 55 0.800 62

5 136 0.728 151

10 225 0.691 249

25 392 0.652 432

50 567 0.626 622

100 794 0.603 868

200 ‐‐‐ ‐‐‐ 1,2611

500 1,610 0.557 1,748

1 200‐year return period was not provided by USGS report and was interpolated from the existing data.

3.6 RAINFALL‐RUNOFF MODEL ESTIMATES

Rainfall‐runoff modeling using HEC‐HMS was conducted to compare the peak flow estimates from the regression equations as described in the following sections.

3.6.1 Precipitation

The point precipitation values for the project were obtained from NOAA Atlas 14, Volume 1, Version 5

(Perica, et al. 2011) using the Precipitation Frequency Data Server (National Oceanic and Atmospheric

Administration 2011). The precipitation values at the basin centroid were assumed to represent the precipitation over the entire project basin area. The point precipitation values for a duration of 24 hours at various return periods are shown in Table 7.

Table 7: NOAA Atlas 14 24‐Hour Point Precipitation – Basin Centroid

Percent Chance Exceedance (%)

Return Period (year)

Point Precipitation (inches)

50 2 2.03

20 5 2.49

10 10 2.86

4 25 3.37

2 50 3.76

1 100 4.16

0.5 200 4.63

0.2 500 5.28

Page 7 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

3.6.2 Basin Parameters

The NRCS curve number (CN) method (Natural Resources Conservation Service 1997) was used to estimate runoff. SSURGO soil information (Natural Resources Conservation Service 2015) is not available for the project basin, however, STATSGO2 soil information (Natural Resources Conservation Service 2016) is available and was used for this assesment. The project area included hydrologic soil groups (HSG) B and

C. Land cover was obtained from the 2016 National Land Cover Dataset (Multi‐Resolution Land

Characteristics Consortium 2019). Land cover for the project basin consists of roughly 65% evergreen forest, 18% grassland/herbaceous, and less than 10% each of shrub/scrub, deciduous forest, mixed forest, barren lands, and open water. Time of concentration was estimated by the NRCS lag time method. The

NRCS method and unit hydrograph was used to estimate peak flows from the basins. The 25% frequency storm distribution was used as outlined in the NMDOT Drainage Design Manual, Section 405.3 (New

Mexico Department of Transportation 2018). A summary of basin parameters is shown in Table 8.

Table 8: Basin Parameters (NRCS Method)

Basin Parameter Site 1

Drainage Area (sq. mi.) 10.8

Composite Curve Number (CN)

65.7

Lag Time (min) 89

The hydrologic computations were carried out using HEC‐HMS, Version 4.4 (U.S. Army Corps of Engineers

2020). The results for various return periods are shown in Table 9.

Table 9: HEC‐HMS Peak Discharge Estimates at Project Site

Exceedance (%)

Return Period (year) Peak Flow (cfs)

50 2 140

20 5 410

10 10 730

4 25 1,280

2 50 1,800

1 100 2,420

0.5 200 3,090

0.2 500 4,100

Page 8 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

3.7 RECOMMENDED DESIGN FLOWS

The above three methods used to compute the project design flows (regression equations, USGS gage analysis, and rainfall‐runoff model) resulted in varied peaks flows at all return periods. Of the three methods, USGS streamflow gage analysis flow rates fell between the regression equation and rainfall‐ runoff method rates. Being that Romero Creek gage is along the same stream and likely within the project basin, it was determined to most accurately reflect the project basin characteristics. In addition, per the

USGS Report 2008‐5119, the drainage area ratio comparing the project site and the gage site is within the recommended range of 0.5‐1.5. While the gage data is older than desired (1958 to 1975), a review of historic maps and aerials has indicated no significant changes throughout the watershed since this time.

Comparing the gage data results to that of the regression equations, the flows are similar for the more frequent storm events while the difference increases as the return period increases. Despite this, the gage data results fall within the standard error of prediction associated with the regression equations.

This correlation was expected as the Romero Creek gage was used in the development of the regression equations. Alternatively, the rainfall‐runoff model resulted in the highest set of peak flows and were between 2 and 4 times higher than the flow rates suggested by both the regression equations and gage comparison for the site.

Ultimately, due to its proximity to the project site, its location along Romero Creek, and the lack of change in the watershed, the USGS streamflow gage analysis was selected. Therefore, per the gage comparison method outlined in Section 3.5, the recommended design flows used for the Romero Creek bridge analysis are presented in below in Table 10.

Table 10: Recommended Design Flows

Exceedance (%)

Return Period (year) Peak Flow (cfs)

50 2 62

20 5 151

10 10 249

4 25 432

2 50 622

1 100 868

0.5 200 1,261

0.2 500 1,748

Additional details of the hydrologic analysis are provided in Appendix A.

Page 9 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

4 HYDRAULIC ANALYSIS

Existing and proposed hydraulic analyses were conducted for the Romero Creek Bridge. The objective of the analyses was to establish water surface elevations, freeboard, and hydraulic capacity requirements using the available data and two‐dimensional hydraulic modeling. The input data, model development, and results are discussed in the following sections.

4.1 TOPOGRAPHIC INFORMATION

Field survey information collected by Central Federal Lands was used to develop the hydraulic models for the sites. The survey information was processed to create triangular irregular network (TIN) surfaces to represent the topography in the streambed and floodplain areas near the existing crossings as shown in

Figure 3. All elevations for the study are in units of feet and are referenced to the North American Vertical

Datum of 1988 (NAVD 88).

Figure 3: Topographic Surface, Elevations in feet referenced to NAVD88

Romero Creek

Page 10 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

4.2 EXISTING HYDRAULIC MODEL DEVELOPMENT

Two‐dimensional hydraulic simulations were conducted using SRH‐2D (U.S. Bureau of Reclamation 2017) to estimate water surface elevations, water depth and flow velocities at the project site. The SRH‐2D computational mesh generation and model pre‐ and post‐processing was performed using the SMS

13.0.11 interface (Aquaveo 2019).

The upstream boundary conditions in the model were specified as a constant discharge using the peak flow values shown in Table 10. The downstream boundary conditions were specified as known water surface elevations obtained using Manning’s equation and a energy grade line slope assumed to equal the streambed slope near the model downstream boundary.

SRH‐2D uses Manning’s “n” values to calculate bed friction. The land use types were delineated from aerial imagery as shown in Figure 4 and assigned standard roughness values. The roughness values used in the model are shown in Table 11.

Table 11: Project Land Cover Types and Manning’s Roughness (Existing)

Land Use Manning's "n"

Main Channel 0.035

Floodplain Trees 0.100

Gravel 0.025

Bare Ground 0.040

Figure 4: Project Land Cover Types and Manning’s Roughness (Existing)

Romero Creek

Page 11 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

Based on preliminary results, the existing bridge does not experience overtopping for any of the design storms and thus, for the existing conditions simulations, the existing bridge opening was modeled as an open channel condition without overtopping. Based on survey data, the bridge low chord was determined to be a constant 8232.9‐ft and the overtopping elevation a constant 8234.8‐ft.

Figure 5: SRH‐2D Mesh Detail near Bridge (Existing)

4.3 EXISTING HYDRAULIC MODEL RESULTS

4.3.1 Existing Conditions

Existing conditions hydraulic simulations using the parameters described in Section 4.2 were conducted for the 2‐, 5‐, 10‐, 25‐, 50‐, 100‐, 200‐, and 500‐year return periods. A summary of existing conditions results was extracted at the upstream bridge face (XS‐1) and approximately one bridge width upstream

(XS‐2). For design purposes, freeboard is typically computed a distance upstream of the bridge to avoid uncertainty associated with the rapid drawdown of water as flow accelerates through the bridge opening.

The results are summarized in Table 12 for the 50‐year and 100‐year return periods, respectively. Maps showing the two‐dimensional water surface elevation and velocity results are included in Appendix B.

Table 12: 50‐year and 100‐year Existing Conditions Hydraulic Results

Location Return Period

(year)

Velocity (ft/s) Depth (ft) WSEL (ft)

Average Maximum Average Maximum Average Maximum

Upstream Bridge Face (XS‐1)

50 9.5 10.8 2.7 4.5 8225.2 8225.8

100 10.4 11.9 3.1 5.2 8226.0 8226.7

16 feet Upstream of Bridge (XS‐2)

50 5.8 7.3 3.4 5.2 8226.5 8226.7

100 5.8 7.7 3.7 6.2 8227.5 8227.9

Page 12 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

The results show that the existing bridge can pass the 50‐year and 100‐year events without a pressure flow condition. In addition, freeboard is not limiting as shown in Table 13. Based on the values estimated at the bridge’s upstream face as well as 16 feet upstream, the existing bridge currently meets the design criteria for both FLH and USFS as described in Section 2. Figures 6 and 7 present the water surface elevation results at the upstream bridge face and 16 feet upstream of the bridge, respectively. In addition, Figure 8 presents the water surface profile through the bridge opening.

Table 13: 50‐year and 100‐year Existing Conditions Freeboard

Return Period

(year) Maximum WSEL

(ft) Freeboard

(ft)

Upstream Bridge Face (XS‐1)

50 8225.8 7.1

100 8226.7 6.2

16 feet Upstream of Bridge (XS‐2)

50 8226.7 6.2

100 8227.9 5.0

Figure 6: Existing Conditions WSEL at Upstream Bridge Face (XS‐1) ‐ Looking Downstream

Page 13 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

Figure 7: Existing Conditions WSEL 16 feet Upstream of Bridge (XS‐2) ‐ Looking Downstream

Figure 8: Existing Conditions Water Surface Profile Through Bridge

Page 14 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

4.3.2 Existing Conditions with Blockages

The existing conditions were also evaluated with a 30% blockage as specified in the USFS design criteria.

For this evaluation, the 50‐year and 100‐year return periods were analyzed using the same parameters described in Section 4.2 with the addition of a 30% obstruction. As discussed above, these scenarios were evaluated to estimate low chord elevation requirements. For comparison with the existing conditions, the blockage results were extracted at the same locations upstream of the crossing and summarized in Table

14. Maps showing the two‐dimensional water surface elevation and velocity results are included in

Appendix B.

Table 14: 50‐year and 100‐year Existing Conditions Hydraulic Results – 30% Blockage

Location Return Period

(year)

Velocity (ft/s) Depth (ft) WSEL (ft)

Average Maximum Average Maximum Average Maximum

Upstream Bridge Face (XS‐1)

50 8.8 10.4 2.9 4.6 8225.4 8225.8

100 9.7 11.4 3.4 5.4 8226.3 8226.8

16 feet Upstream of Bridge (XS‐2)

50 5.7 7.2 3.4 5.3 8226.6 8226.8

100 5.7 7.5 3.9 6.3 8227.7 8228.0

The results show that the existing bridge with the 30% blockage can still pass the 50‐year and 100‐year event without a pressure flow condition with only a slight rise in WSEL (approximately 0.1 ft). In addition, freeboard is shown in Table 15. Based on the values estimated at the bridge’s upstream face as well as 16 feet upstream, the existing bridge with the 30% blockage still meets the design criteria for both FHL and

USFS as described in Section 2.

Table 15: 50‐year and 100‐year Existing Conditions Freeboard – 30% Blockages

Location Return Period

(year) Maximum WSEL

(ft) Freeboard

(ft)

Upstream Bridge Face (XS‐1)

50 8225.8 7.1

100 8226.8 6.1

16 feet Upstream of Bridge (XS‐2)

50 8226.8 6.1

100 8228.0 4.9

4.4 PROPOSED HYDRAULIC MODEL DEVELOPMENT

While the existing bridge configuration is adequately sized to meet the design criteria, the existing abutments are in a state of deterioration and will be replaced as part of the bridge replacement. The proposed construction consists of the installation of two new spread footing foundations behind the existing abutments, the removal of the existing abuments, installation of new spill‐through abutments, and the installation of a new modular steel bridge with an approximate bridge opening of 45 feet and a low chord elevation of 8231.6. A draft Bridge Plan & Elevation sheet is provided in Appendix C.

The existing two‐dimensional hydraulic model, detailed in Section 4.2, was adapted to reflect the new bridge configuration outlined above. The proposed changes include adjusting surface roughness values and modifying the terrain model to accurately reflect the new bridge opening. The revised roughness and terrain models are depicted below in Figures 9 and 10 respectively. Upstream and downstream boundary conditions as well as peak flow rates were not modified from the existing model.

Page 15 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

Figure 9: Project Land Cover Types and Manning’s Roughness (Proposed)

Figure 10: SRH‐2D Mesh Detail near Bridge (Proposed)

Romero Creek Bridge

(increased bridge opening)

Page 16 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

4.5 PROPOSED HYDRAULIC MODEL RESULTS

4.5.1 Proposed Conditions

Proposed conditions hydraulic simulations using the parameters described in Section 4.4 were conducted for the 2‐, 5‐, 10‐, 25‐, 50‐, 100‐, 200‐, and 500‐year return periods. A summary of proposed conditions results was extracted at the upstream bridge face (XS‐1) and approximately one bridge width upstream

(XS‐2). For design purposes, freeboard is typically computed a distance upstream of the bridge to avoid uncertainty associated with the rapid drawdown of water as flow accelerates through the bridge opening.

The results are summarized in Table 16 for the 50‐year and 100‐year return periods, respectively. Maps showing the two‐dimensional water surface elevation and velocity results are included in Appendix C.

Table 16: 50‐year and 100‐year Proposed Conditions Hydraulic Results

Return Period

(year)

Velocity (ft/s) Depth (ft) WSEL (ft)

Average Maximum Average Maximum Average Maximum

Upstream Bridge Face (XS‐1)

50 7.2 10.0 2.6 4.1 8225.6 8226.2

100 7.8 10.7 3.1 4.8 8226.4 8227.1

16 feet Upstream of Bridge (XS‐2)

50 6.4 8.3 2.9 4.8 8226.1 8226.2

100 7.1 9.1 3.2 5.6 8226.8 8226.9

The results show that the proposed bridge continue to pass the 50‐year and 100‐year events without a pressure flow condition. In addition, freeboard is not limiting as shown in Table 17. Based on the values estimated at the bridge’s upstream face as well as 16 feet upstream, the existing bridge currently meets the design criteria for both FLH and USFS as described in Section 2. Figures 11 and 12 present the water surface elevation results at the upstream bridge face and 16 feet upstream of the bridge, respectively. In addition, Figure 13 presents the water surface profile through the bridge opening.

Table 17: 50‐year and 100‐year Proposed Conditions Freeboard

Return Period

(year) Maximum WSEL

(ft) Freeboard

(ft)

Upstream Bridge Face (XS‐1)

50 8226.2 5.4

100 8227.1 4.5

16 feet Upstream of Bridge (XS‐2)

50 8226.2 5.4

100 8226.9 4.7

Page 17 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

Figure 11: Proposed Conditions WSEL at Upstream Bridge Face (XS‐1) ‐ Looking Downstream

Figure 12: Proposed Conditions WSEL 16 feet Upstream of Bridge (XS‐2) ‐ Looking Downstream

Page 18 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

Figure 13: Proposed Conditions Water Surface Profile Through Bridge

4.5.2 Proposed Conditions with Blockages

The proposed conditions were also evaluated with a 30% blockage as specified in the USFS design criteria.

For this evaluation, the 50‐year and 100‐year return periods were analyzed using the same parameters described in Section 4.4 with the addition of a 30% obstruction. As discussed above, these scenarios were evaluated to estimate low chord elevation requirements. For comparison with the existing conditions, the blockage results were extracted at the same locations upstream of the crossing and summarized in Table

18. Maps showing the two‐dimensional water surface elevation and velocity results are included in

Appendix C.

Table 18: 50‐year and 100‐year Proposed Conditions Hydraulic Results – 30% Blockage

Location Return Period

(year)

Velocity (ft/s) Depth (ft) WSEL (ft)

Average Maximum Average Maximum Average Maximum

Upstream Bridge Face (XS‐1)

50 6.2 9.2 2.7 4.5 8225.9 8226.4

100 6.3 9.7 3.1 5.3 8226.8 8227.4

16 feet Upstream of Bridge (XS‐2)

50 6.2 7.9 3.0 5.0 8226.2 8226.3

100 6.8 8.7 3.4 5.8 8227.0 8227.1

The results show that the proposed bridge with the 30% blockage continues to pass the 50‐year and 100‐ year event without a pressure flow condition with only a slight rise in WSEL (0.1‐0.3 feet). In addition, freeboard is shown in Table 19. Based on the values estimated at the bridge’s upstream face as well as 16

Page 19 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report feet upstream, the existing bridge with the 30% blockage still meets the design criteria for both FHL and

USFS as described in Section 2.

Table 19: 50‐year and 100‐year Proposed Conditions Freeboard – 30% Blockages

Return Period

(year) Maximum WSEL

(ft) Freeboard

(ft)

Upstream Bridge Face (XS‐1)

50 8226.4 5.2

100 8227.4 4.2

16 feet Upstream of Bridge (XS‐2)

50 8226.3 5.3

100 8227.1 4.5

4.6 HYDRAULIC MODEL SUMMARY TABLES

Hydraulic variables including shear stress, Froude number, velocity, water depth, and water surface elevation are computed by the hydraulic model for specified cross sections. For the Romero Creek bridge, these variables were computed at the upstream bridge face (XS‐1) as well as 16 feet upstream (XS‐2) as depicted in Figures 5 and 10. Tables 20 and 21 below provide the average and maximum values for each cross section, model scenario, and variable.

Table 20: Existing Conditions Hydraulic Model Summary Table

Cross Section

Model Scenario

Shear Stress (lb/ft2)

Froude Number

Velocity (ft/s)

Water Depth (ft)

Water Elevation (ft)

Ave Max Ave Max Ave Max Ave Max Ave Max

Upstream Bridge Face

(XS‐1)

2YR (62 cfs) 0.4 0.5 0.54 0.82 3.0 3.9 1.2 1.9 8222.9 8222.9

5YR (151 cfs) 0.9 1.1 0.81 1.44 4.6 6.0 1.5 2.5 8223.4 8223.5

10YR (249 cfs) 1.8 2.4 1.07 2.33 6.8 7.8 1.9 3.0 8223.8 8223.9

25YR (432 cfs) 2.5 3.6 1.27 2.95 8.3 9.5 2.3 3.7 8224.5 8224.8

50YR (622 cfs) 3.1 4.5 1.38 5.70 9.5 10.8 2.7 4.5 8225.2 8225.8

100YR (868 cfs) 3.5 5.1 1.25 2.08 10.4 11.9 3.1 5.2 8226.0 8226.7

200YR (1,261 cfs) 4.2 5.6 1.19 1.88 11.9 13.2 3.9 6.2 8226.9 8227.8

500YR (1,748 cfs) 4.4 6.2 1.19 6.66 13.0 14.1 5.0 7.4 8228.1 8233.0

50YR (622 cfs) ‐ 30% Obs 2.6 4.2 1.08 1.81 8.8 10.4 2.9 4.6 8225.4 8225.8

100YR (868 cfs) ‐ 30% Obs 2.9 4.4 1.11 1.91 9.7 11.4 3.4 5.4 8226.3 8226.8

16 Feet Upstream of Bridge

(XS‐2)

2YR (62 cfs) 0.5 0.7 0.71 0.78 3.1 4.8 0.9 1.7 8222.9 8223.0

5YR (151 cfs) 0.8 1.0 0.93 1.72 4.1 6.1 1.2 2.5 8223.7 8223.8

10YR (249 cfs) 1.1 1.3 0.80 1.31 4.8 6.7 1.8 3.2 8224.4 8224.6

25YR (432 cfs) 1.0 1.4 0.68 0.95 5.2 7.1 2.4 4.3 8225.5 8225.7

50YR (622 cfs) 1.1 1.4 0.60 1.13 5.8 7.3 3.4 5.2 8226.5 8226.7

100YR (868 cfs) 1.1 1.5 0.64 1.19 5.8 7.7 3.7 6.2 8227.5 8227.9

200YR (1,261 cfs) 1.0 1.5 0.56 1.14 5.7 8.3 4.2 7.6 8229.0 8229.4

500YR (1,748 cfs) 1.1 3.3 0.56 1.38 5.8 8.8 5.1 9.1 8230.6 8231.1

50YR (622 cfs) ‐ 30% Obs 1.0 1.4 0.58 0.76 5.7 7.2 3.4 5.3 8226.6 8226.8

100YR (868 cfs) ‐ 30% Obs 1.0 1.4 0.61 0.97 5.7 7.5 3.9 6.3 8227.7 8228.0

Page 20 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

Table 21: Proposed Conditions Hydraulic Model Summary Table

Cross Section

Model Scenario

Shear Stress (lb/ft2)

Froude Number

Velocity (ft/s)

Water Depth (ft)

Water Elevation (ft)

Ave Max Ave Max Ave Max Ave Max Ave Max

Upstream Bridge Face

(XS‐1)

2YR (62 cfs) 0.5 0.8 0.68 1.10 3.2 4.6 0.9 1.6 8222.9 8222.9

5YR (151 cfs) 1.0 1.4 0.83 1.63 4.7 6.5 1.4 2.3 8223.6 8223.8

10YR (249 cfs) 1.2 1.9 0.83 1.49 5.4 7.7 1.7 2.7 8224.1 8224.4

25YR (432 cfs) 1.6 2.6 0.88 1.53 6.4 9.1 2.2 3.5 8224.9 8225.4

50YR (622 cfs) 1.9 3.1 0.96 2.12 7.2 10.0 2.6 4.1 8225.6 8226.2

100YR (868 cfs) 2.1 3.5 0.87 1.53 7.8 10.7 3.1 4.8 8226.4 8227.1

200YR (1,261 cfs) 2.3 3.9 0.88 1.70 8.5 11.6 3.7 5.7 8227.4 8228.2

500YR (1,748 cfs) 2.6 4.3 0.94 2.26 9.4 12.4 4.4 6.8 8228.4 8229.4

50YR (622 cfs) ‐ 30% Obs 1.4 2.5 0.78 1.47 6.2 9.2 2.7 4.5 8225.9 8226.4

100YR (868 cfs) ‐ 30% Obs 1.5 2.6 0.76 1.42 6.3 9.7 3.1 5.3 8226.8 8227.4

16 Feet Upstream of Bridge

(XS‐2)

2YR (62 cfs) 0.5 0.6 0.64 0.77 2.9 4.5 1.0 1.9 8223.1 8223.1

5YR (151 cfs) 0.7 1.0 0.68 0.77 4.0 5.9 1.4 2.7 8223.8 8223.9

10YR (249 cfs) 1.1 1.3 0.80 1.05 4.7 6.7 1.7 3.3 8224.5 8224.6

25YR (432 cfs) 1.3 1.7 0.83 1.17 5.3 7.5 2.2 4.2 8225.4 8225.5

50YR (622 cfs) 1.6 2.0 0.82 1.21 6.4 8.3 2.9 4.8 8226.1 8226.2

100YR (868 cfs) 1.8 2.4 0.85 1.40 7.1 9.1 3.2 5.6 8226.8 8226.9

200YR (1,261 cfs) 2.1 2.6 0.87 1.37 7.6 9.9 3.7 6.5 8227.9 8228.3

500YR (1,748 cfs) 2.4 2.9 0.84 1.13 9.0 10.8 4.6 7.5 8228.8 8229.2

50YR (622 cfs) ‐ 30% Obs 1.5 1.8 0.77 1.18 6.2 7.9 3.0 5.0 8226.2 8226.3

100YR (868 cfs) ‐ 30% Obs 1.6 2.1 0.79 1.35 6.8 8.7 3.4 5.8 8227.0 8227.1

4.7 SCOUR CONSIDERATIONS

The proposed bridge abutments will consist of vertical concrete abutments founded on shallow spread footings. The footings will extend to embedment on underlying bedrock. Final footing depths were estimated based on the geotechnical investigation conducted for the project which found shallow bedrock at both abutment locations (see Geotechnical Report). In addition to the bedrock located at each proposed abutment location, the channel bed through the bridge is also dominated by bedrock material, and as such, contraction scour and local abutment scour are not anticipated. It is assumed that during large flood events, loose stream bed and bank material may be mobilized but will only scour to the depth of bedrock. Being that the abutments are located on, and the channel bed is dominated by, bedrock, scour was not computed for this crossing. Furthermore, the proposed bridge configuration will result in an increased bridge opening accompanied by a slight reduction in floodplain contraction and peak flow velocities for larger flood events.

Page 21 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

5 SUMMARY

Hydrology and hydraulics analyses were conducted for the Romero Creek Bridge project. Based on these analyses, both the existing and proposed bridge configurations are able to pass floods greater than the

100‐year event without experiencing overtopping of the roadway. The proposed bridge configuration consists of the installation of two new spread footing foundations, the removal of the existing abuments, installation of new spill‐through abutments, and the installation of a new modular steel bridge with an approximate bridge opening of 45 feet and a low chord elevation of 8232.1. Comparing the existing and proposed hydrualic results, it should be noted that the proposed bridge configuration results in a slight increase in WSEL (approximately 0.5 feet) through the bridge opening but is accompanied by a reduction of average and maximum velocities as well as a reduction in average water depth, ultimately improving bridge function. Table 22 shows the minimum low chord elevation required to satisfy FLH PDDM criteria, USFS TSH criteria, and USFS TSH criteria including 30% debris blockage of the bridge opening. Based on the proposed low chord elevation and bridge configuration, the proposed bridge meets the minimum freeboard requirement for all three design criteria.

Table 22: Summary of Bridge Freeboard Results

Design Criteria

Hydraulic Capacity Design

Frequency

Bridge Waterway Width (ft)

Minimum Freeboard

(ft)

Maximum

WSEL 16‐

feet Upstream

(ft)

Proposed Low Chord Elevation

(ft)

Provided Freeboard

(ft)

Meets Design Criteria (Yes/No)

FLH PDDM 50‐year 45 2 8,226.2

8,231.6

5.4 Yes

USFS TSH 100‐year 45 3 8,226.9 4.7 Yes

USFS TSH –

including 30%

Debris Blockage

100‐year 45 3 8,227.1 4.5 Yes

Page 22 NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

6 REFERENCES

Aquaveo. 2019. Surface‐water Modeling System (SMS), version 13.0.5. Provo, UT.

Federal Highway Administration . 2009. "Bridge Scour and Stream Instability Countermeasures ‐

Experience, Selection, and Design Guidelines, Hydraulic Engineering Circular No. 23, Third Edition, FHWA‐NHI 09‐111 (Vol. 1), FHWA‐NHI‐09‐112 (Vol. 2)." Federal Highway Administration, Washington, DC.

Federal Lands Highway. 2012. "Project Development and Design Manual, Chapter 7 Hydrology and

Hydraulics." https://flh.fhwa.dot.gov/resources/design/pddm/.

Multi‐Resolution Land Characteristics Consortium. 2019. National Land Cover Database 2016 (NLCD

2016). 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. 2016. Digital General Soil Map of the United States (STATSGO2).

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.

New Mexico Department of Transportation. 2018. "Drainage Design Manual."

https://dot.state.nm.us/content/dam/nmdot/Infrastructure/Drain_Design_Manual.pdf.

Perica, Sanja, Sarah Dietz, Sarah Heim, Lillian Hiner, Kazungu Maitaria, Deborah Martin, Sandra Pavlovic, et al. 2011. "Precipitation Frequency Atlas of the United States Volume 1 Version 5.0: Semiarid

Southwest (Arizona, Southeast California, Nevada, New Mexico, Utah)." NOAA Atlas 14, Silver

Spring, MD.

U.S. Army Corps of Engineers. 2020. HEC‐HMS, Hydrologic Engineering Center Hydrologic Modeling

System. Version 4.4. Davis, CA.

U.S. Bureau of Reclamation. 2017. SRH‐2D, Sedimentation and River Hydraulics – Two‐Dimensional model.

Version 3.2.

U.S. Forest Service. 2014. "Transportation Structures Handbook." FSH 7709.56b.

U.S. Geological Survey. 2016. StreamStats Program. http://streamstats.usgs.gov.

Waltemeyer, S.D. 2008. Analysis of the Magnitude and Frequency of Peak Discharge and Maximum

Observed Peak Discharge in New Mexico and Surrounding Areas. Scientific Investigaitons Report

2008‐5119, U.S. Geological Survey. https://doi.org/10.3133/sir20145211.

NM FS 220(1) Romero Creek Bridge – Final Hydraulic Report

Appendix A – Hydrologic Analyses

StreamStats Information

2/19/2020 StreamStats https://streamstats.usgs.gov/ss/ 1/3

Romero Creek Bridge - NM FS 220(1)

Basin Characteristics

Parameter Code Parameter Description Value Unit

DRNAREA Area that drains to a point on a stream 10.8 square miles

BSLDEM30ff Mean basin slope computed from 30 m DEM in feet per foot

0.18 percent

PRECIP Mean Annual Precipitation 25.3 inches

HIGHREG HIGHREG 1099 dimensionless

ELEV Mean Basin Elevation 8890 feet

I24H100YA2 Maximum 24-hour precipitation that occurs on average once in 100 years from NOAA Atlas 2

4.24 inches

Region ID: NM Workspace ID: NM20200219160339103000 Clicked Point (Latitude, Longitude): 33.91093, -109.02388 Time: 2020-02-19 09:03:43 -0700 https://streamstats.usgs.gov/ss/ 2/3

Parameter Code Parameter Description Value Unit

OUTLETELEV Elevation of the stream outlet in thousands of feet above NAVD88.

8221 feet

PREC10to4 Mean precipitation for winter period defined as October to April

12.7 inches

Peak-Flow Statistics Parameters[Peak 2008 5119 SW Mountain Flood Region 8]

Parameter Code Parameter Name Value Units Min Limit Max Limit

DRNAREA Drainage Area 10.8 square miles 1.7 1200

HIGHREG HIGHREG 1099 dimensionless

Peak-Flow Statistics Flow Report[Peak 2008 5119 SW Mountain Flood Region 8]

PIl: Prediction Interval-Lower, PIu: Prediction Interval-Upper, SEp: Standard Error of Prediction, SE:

Standard Error (other -- see report)

Statistic Value Unit SE SEp

2 Year Peak Flood 60.3 ft^3/s 55 55

5 Year Peak Flood 142 ft^3/s 45 45

10 Year Peak Flood 223 ft^3/s 43 43

25 Year Peak Flood 360 ft^3/s 45 45

50 Year Peak Flood 490 ft^3/s 46 46

100 Year Peak Flood 646 ft^3/s 51 51

500 Year Peak Flood 1130 ft^3/s 62 62

Peak-Flow Statistics Citations

Waltemeyer, S.D.,2008, Analysis of the Magnitude and Frequency of Peak Discharge and Maximum Observed Peak Discharge in New Mexico and Surrounding Areas: U.S. Geological Survey Scientific Investigations Report 2008-5119, 105 p.

(http://pubs.usgs.gov/sir/2008/5119/)

USGS Data Disclaimer: Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty http://pubs.usgs.gov/sir/2008/5119/ https://streamstats.usgs.gov/ss/ 3/3 expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty.

USGS Software Disclaimer: This software has been approved for release by the U.S. Geological Survey (USGS). Although the software has been subjected to rigorous review, the USGS reserves the right to update the software as needed pursuant to further analysis and review. No warranty, expressed or implied, is made by the USGS or the U.S. Government as to the functionality of the software and related material nor shall the fact of release constitute any such warranty. Furthermore, the software is released on condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from its authorized or unauthorized use.

USGS Product Names Disclaimer: Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Application Version: 4.3.11

9/2/2020 StreamStats Data-Collection Station Report https://streamstatsags.cr.usgs.gov/gagepages/html/09442650.htm 1/3

StreamStats Data-Collection Station Report

USGS Station Number 09442650 Station Name ROMERO CRK NR N.M.-ARIZ. ST. LINE NR LUNA, NM

Click here to link to available data on NWIS-Web for this site.

Click here to link to available Iowa stream flow statistics.

Click here to link to available flow-duration statistics by period of record, calendar day and month, and selected seasonal periods.

Descriptive Information

Station Type Streamgage, continuous record Location Gage Regulation and Diversions Regulated? False Period of Record Remarks Latitude (degrees NAD83) 33.95005174 Longitude (degrees NAD83) -108.98396334 Hydrologic unit code 15040004 County 003-Catron HCDN2009 No

Physical Characteristics

Characteristic Name Value Units Citation Number

Descriptive Information High_Flow_Region_Code 8 dimensionless 149 High_Flow_Regression_Equation Y Yes or No 149 Datum_of_Latitude_Longitude NAD83 dimensionless 30 District_Code 35 dimensionless 30 Precipitation Statistics 24_Hour_2_Year_Precipitation 1.8000 inches 31 24_Hour_10_Year_Precipitation 2.5000 inches 31 24_Hour_25_Year_Precipitation 3.0200 inches 31 24_Hour_50_Year_Precipitation 3.4000 inches 31 24_Hour_100_Year_Precipitation 4.24 inches 149 Mean_Annual_Precipitation 25.83 inches 149 Mean_Oct_to_Apr_Precipitation 13.31 inches 149 6_Hour_100_Year_Precipitation 3.34 inches 149 Temperature Statistics Mean_Min_January_Temperature 11.000 degrees F 31 Topographical Characteristics Elevation_of_10_and_85_points 8980.00 feet 31 Mean_Basin_Elevation 8760 feet 149 Mean_Basin_Slope_from_30m_DEM_ft_per_ft 0.177 feet per foot 149 Basin_Average_Aspect 225 degrees C 149 http://nwis.waterdata.usgs.gov/nwis/inventory/?site_no=09442650 https://streamstatsags.cr.usgs.gov/IA_gagePages/09442650_stats.pdf https://streamstatsags.cr.usgs.gov/NC_gagePages/Sta_09442650_daily_discharge_percentiles_table_by-day-month-seasonal.txt https://streamstatsags.cr.usgs.gov/gagepages/html/09442650.htm 2/3

Land Cover Characteristics Percent_Forest 84.000 percent 31 Percent_Storage 0.0000 percent 31 Stream Channel Properties Main_Channel_Length 6.0000 miles 31 Stream_Slope_10_and_85_Method 160.000 feet per mi 31 Basin Dimensional Characteristics Contributing_Drainage_Area 10.800 square miles 31 Drainage_Area 10.8 square miles 30 Drainage_Area 9.37 square miles 149

Streamflow Statistics

Statistic Name Value Units Citation Number Preferred?

Years of

Record

Standard Error, percent Variance log-10

Lower 95% Confidence

Interval

Upper 95% Confidence

Interval Start Date

End Date Remarks

Peak-Flow Statistics 2_Year_Peak_Flood 55 cubic feet per second

149 Y 19

5_Year_Peak_Flood 136 cubic feet per second

149 Y 19

10_Year_Peak_Flood 225 cubic feet per second

149 Y 19

25_Year_Peak_Flood 392 cubic feet per second

149 Y 19

50_Year_Peak_Flood 567 cubic feet per second

149 Y 19

100_Year_Peak_Flood 794 cubic feet per second

149 Y 19

500_Year_Peak_Flood 1610 cubic feet per second

149 Y 19

Regression_2_Year_Peak_Flood 54 cubic feet per second

149 Y

Regression_5_Year_Peak_Flood 128 cubic feet per second

149 Y

Regression_10_Year_Peak_Flood 202 cubic feet per second

149 Y

Regression_25_Year_Peak_Flood 328 cubic 149 Y https://streamstatsags.cr.usgs.gov/gagepages/html/09442650.htm 3/3 feet per second

Regression_50_Year_Peak_Flood 448 cubic feet per second

149 Y

Regression_100_Year_Peak_Flood 594 cubic feet per second

149 Y

Regression_500_Year_Peak_Flood 1050 cubic feet per second

149 Y

Weighted_5_Year_Peak_Flood 134 cubic feet per second

149 Y

Weighted_10_Year_Peak_Flood 216 cubic feet per second

149 Y

Weighted_25_Year_Peak_Flood 363 cubic feet per second

149 Y

Weighted_50_Year_Peak_Flood 509 cubic feet per second

149 Y

Weighted_100_Year_Peak_Flood 693 cubic feet per second

149 Y

Weighted_500_Year_Peak_Flood 1310 cubic feet per second

149 Y

Weighted_2_Year_Peak_Flood 54 cubic feet per second

149 Y

Citations

Citation Number

Citation Name and URL

30 Imported from NWIS file 31 Imported from Basin Characteristics file 149 Waltemeyer, S.D., 2008, Analysis of the Magnitude and Frequency of Peak Discharge and Maximum Observed Peak

Discharge in New Mexico and Surrounding Areas: U.S. Geological Survey Scientific Investigations Report 2008- 5119, 105 p.

http://waterdata.usgs.gov/nwis/si http://pubs.usgs.gov/sir/2008/5119/

Precipitation Frequency Data Server Information

8/18/2020 Precipitation Frequency Data Server https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=33.9203&lon=-109.0759&data=depth&units=english&series=pds 1/4

NOAA Atlas 14, Volume 1, Version 5 Location name: Eagar, Arizona, USA*

Latitude: 33.9203°, Longitude: -109.0759° Elevation: 8491.21 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 0.260 (0.228‑0.298)

0.332 (0.290‑0.379)

0.429 (0.375‑0.487)

0.500 (0.435‑0.568)

0.595 (0.513‑0.673)

0.665 (0.572‑0.755)

0.737 (0.630‑0.839)

0.809 (0.685‑0.926)

0.902 (0.751‑1.04)

0.978 (0.804‑1.15)

10-min 0.396 (0.347‑0.453)

0.505 (0.442‑0.577)

0.653 (0.571‑0.742)

0.761 (0.662‑0.864)

0.905 (0.781‑1.02)

1.01 (0.871‑1.15)

1.12 (0.958‑1.28)

1.23 (1.04‑1.41)

1.37 (1.14‑1.59)

1.49 (1.23‑1.74)

15-min 0.491 (0.430‑0.562)

0.626 (0.548‑0.715)

0.810 (0.708‑0.920)

0.944 (0.821‑1.07)

1.12 (0.968‑1.27)

1.25 (1.08‑1.42)

1.39 (1.19‑1.58)

1.53 (1.29‑1.75)

1.70 (1.42‑1.97)

1.85 (1.52‑2.16)

30-min 0.661 (0.579‑0.756)

0.844 (0.738‑0.963)

1.09 (0.953‑1.24)

1.27 (1.11‑1.44)

1.51 (1.30‑1.71)

1.69 (1.45‑1.92)

1.87 (1.60‑2.13)

2.06 (1.74‑2.35)

2.29 (1.91‑2.65)

2.49 (2.04‑2.91)

60-min 0.818 (0.716‑0.936)

1.04 (0.913‑1.19)

1.35 (1.18‑1.53)

1.57 (1.37‑1.79)

1.87 (1.61‑2.12)

2.09 (1.80‑2.37)

2.32 (1.98‑2.64)

2.54 (2.15‑2.91)

2.84 (2.36‑3.28)

3.08 (2.53‑3.60)

2-hr 0.911 (0.788‑1.05)

1.15 (1.00‑1.32)

1.48 (1.28‑1.68)

1.74 (1.50‑1.98)

2.09 (1.80‑2.38)

2.37 (2.02‑2.71)

2.67 (2.25‑3.05)

2.97 (2.48‑3.41)

3.38 (2.78‑3.91)

3.71 (3.01‑4.32)

3-hr 0.987 (0.869‑1.13)

1.24 (1.09‑1.42)

1.56 (1.38‑1.79)

1.83 (1.60‑2.09)

2.21 (1.91‑2.53)

2.51 (2.15‑2.88)

2.83…