NM FLAP SJU 10(1) Cottonwood Hydraulics.pdf

Cottonwood Campground

NM FLAP SJU 10(1)

Hydrology and Hydraulics Recommendations Report

Federal Highway Administration Central Federal Lands Highway Division

Prepared by HDR Engineering, Inc.

March 1st, 2021

ACORONEL

Cottonwood Campground 1 Central Federal Lands Highway Hydrology and Hydraulics

Recommendations Report

1 Introduction HDR is preparing a Project Delivery Plan for the Federal Highway Administration, Central Federal Lands Highway Division (CFLHD) for proposed improvements to Cottonwood Campground, in San Juan County, New Mexico (Figure 1-1), which includes the proposed construction of a bridge over an existing unnamed wash (Cottonwood Campground Wash) for access to the campground and channel improvements, including a plunge pool, to a narrow location (channel contraction) within the existing wash approximately 600 feet upstream of the existing low flow crossing. This Scope of Work (SOW) is to perform engineering, hydraulic, geotechnical, scour/erosion and project management services towards delivery of a final set of plans, specifications and estimate for this CFLHD project.

1.1 Project Description

Access to Cottonwood Campground is currently provided from Road 4280, which is a two-lane road with 11-foot lanes and has a total width of approximately 22 feet (there are currently no road shoulders). Cottonwood campground is located in Navajo Sate Park in San Juan County, New Mexico.

Cottonwood Campground experiences annual flooding events which temporarily cuts off traffic and emergency ingress and egress from the campground due to the amount of sand transported by the wash during flood events. The road and the bridge are maintained by the NM State Park staff. Current regular maintenance is required to clear the sand from the roadway surface before it can be reopened to traffic and emergency services.

This Task Order is to design and prepare the PS&E package for the new bridge structure. The new bridge is proposed to include two 12-foot lanes 105 feet long with 4-foot-wide shoulders and metal railings for a total out to out width of 35 feet. This report serves as the basis for hydrologic and hydraulic analysis for the proposed bridge and provides bridge scour calculations.

This Task Order is to also design and prepare the PS&E package for a plunge pool and armoring of a channel contraction upstream of the proposed bridge location. This report also provides recommendations for the proposed riprap sizing of this contracted section.

In July 2017 the Bureau of Reclamation (BOR) developed an Appraisal Design Report for the Cottonwood Campground Wash entitled Cottonwood Campground Low Water Crossing (BOR, 2017). Where applicable, analysis approaches used in this report (BOR 2017 report) were incorporated into the present analysis.

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Figure 1-1. Project Location

1.2 Project Vicinity

The Cottonwood Campground is located next to the San Juan River downstream of Navajo Dam in Northern New Mexico. The proposed roadway bridge over the Cottonwood Campground Wash will be located approximately 110 feet upstream of the existing low flow crossing location.

The proposed bridge is also approximately 1,270 feet from the confluence with the San Juan River (Figure 1-2). The existing plunge pool is approximately 600 feet upstream of the existing low flow crossing and 490 feet upstream of the proposed bridge.

Federal Emergency Management Agency (FEMA) has designated the flood hazard area within the project site as a FEMA Zone A based on the San Juan River floodplain, as determined by the Flood Insurance Rate Maps (FIRM) #35045C0800F, effective date August 5, 2010, as shown in Appendix A. The National Flood Hazard Layer (NFHL) mapped against the project location is also provided in Figure 1-3. Floodplains designated Zone A are subject to inundation by the 1-percent-annual-chance flood (100-year) event. Because detailed hydraulic analyses have not been performed, no Base Flood Elevations (BFEs) or flood depths are shown or available.

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Figure 1-2. Project Vicinity

Figure 1-3. Project Location Mapped against the FEMA NFHL

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1.3 Design Criteria

The NMDOT Drainage Design Manual (NMDOT DDM) (Smith Engineering Company et al., 2018) supplemented with Chapter 7 of the Federal Lands Highway Project Development and Design Manual (FLH PDDM) (Federal Highway Administration, 2012) are used as the basis to evaluate the proposed bridge over the Cottonwood Campground Wash.

According to the NMDOT DDM, the design criteria for bridged waterways specify that bridges with an Average Daily Traffic (ADT) less than 400 vehicles need be designed to convey the 25-year flood with a 50-year check flood (2% annual exceedance probability [AEP]). The associated stability design and scour analysis is then for the 50-year flood (2% AEP) with a 100-year check flood (1% AEP). All bridges need to be designed with an additional 2 feet of freeboard. The ADT for the proposed bridge over the Cottonwood Campground Wash is assumed to be less than 400 ADT.

According to the FLH PDDM, the design criteria for bridged waterways specify that bridges need to convey the 50-year flood (2% AEP) with appropriate freeboard (p.7-68). The required minimum freeboard height is 2 feet given that the potential for woody debris is not considered significant nor is there a potential for ice flows (p. 7-69). The check flood for water surface increases is then the greater between the 100-year flood (1% AEP) and the overtopping flood.

For stability design and scour analysis, the 100-year flood (1% AEP) is specified for design and the 200-year flood (0.5% AEP) is the check flood (p. 7-68).

Given the location of the bridge in a rural area with an assumed ADT less than 400, the NMDOT DDM will serve as the default criteria for the proposed bridge over the Cottonwood Campground Wash and will be designed based on the following:

Conveyance of 25-year flows (4% AEP) with 2 feet of freeboard below the low chord per NMDOT DDM criteria.

A check flood that considers the 50-year flows (1% AEP) per NMDOT DDM criteria.

Abutment benches that extend above the Energy Grade Line for 25-year flows and riprap that extends above the 50-year EGL, per NMDOT DDM criteria.

Stability and scour analysis based on 50-year flow (1% AEP) and a check flood based on 100-year flows, per NMDOT DDM criteria.

The Cottonwood Campground Wash discharges to the San Juan River about 1,270 feet downstream of the proposed bridge. Neither the FLH PDDM nor the NMDOT DDM provide guidance for coincident flows in a downstream water body. The Federal Highway Administration (FHWA) also does not provide guidance specifically for bridge design but they do, however, provide guidance for urban drainage design in Table 7-3 contained in Hydraulic Engineering Circular No. 22 (FHWA, 2009). Based on this guidance, a 2-year (50% AEP) downstream coincident flow rate is assumed in the San Juan River. The BOR 2017 report also noted that nearly 80 percent of rainfall and subsequent runoff events occur between July and

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January, meaning that runoff events in the Cottonwood Campground Wash are not likely to align with flood releases from Navajo Dam.

2 Hydrology Flood Insurance Study (FIS) Number #35045C0800F was developed by FEMA for San Juan County, New Mexico, and incorporated areas. The project area, however, is mapped as a Zone A in the FIS and only applies to the San Juan River, therefore flow rates to the project location are not available. The NMDOT DDM was therefore used as guidance for developing flows for the project location.

2.1 Cottonwood Campground Wash

The total drainage area for the Cottonwood Campground Wash is approximately 530 acres (0.83 square miles), with the contributing area to the proposed bridge being about 483 acres (0.75 square miles) (Figure 2-3). General characteristics of the watershed include the following:

The majority of the watershed is Dessert shrub. The density of the desert shrub varies throughout with the watershed.

The uppermost elevation of the watershed is at elevation 6465. The elevation at the uppermost portion of the modeled reach is at elevation 5725. The elevation at the bottom end of the Cottonwood wash is at approximate elevation 5680.

There is 340 to 400 foot steep cliff cuts through the watershed, accounting for over have the elevation drop in the watershed.

Some of these characteristics are illustrated in Figure 2-1, Figure 2-2, and Figure 2-3. Peak discharges were estimated at three locations in the project area:

Uppermost location in the hydraulic model (Upper Limit) Immediately upstream of the proposed bridge location (Future Bridge) Downstream of the bridge location near the confluence to the San Juan River (Lower

Limit)

Given that the contributing drainage area is greater than 160 acres but less than 10 square miles, the Simplified Peak Discharge Method was used to develop peak flows per the NMDOT DDM (p. 4-6). This method uses NRCS curve numbers to develop the runoff volume via equation 404-1 in the NMDOT DDM:

Q = (P-(200/CN)+2)^2)/(P + 800/CN)-8)

Where:

Q = direct runoff, inches

P = 24-hour rainfall depth, inches

CN = NRCS Curve Number

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Curve numbers were estimated by developing a land use file within GIS and assigning cover types using information from Table 402-1 in the NMDOT DDN (p. 4-28), which are consistent with the NRCS TR-55 (NRCS, 1986), as well as photos from various site visits and GIS aerial photography. Soil data was extracted from the NRCS Soil Survey Geographic Database (SSURGO) using the NRCS Soil Data Viewer (https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/soils/survey/geo/?cid=nrcs142p2_053620) in GIS and verified with a soil data report generated via the NRCS Web Soil Survey (https://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx). Curve numbers were then developed using the before mentioned land use and soil files and then composited using routines within GIS. Figure 2-4 presents the curve numbers assumed for this analysis and Figure 2-5 presents the hydrologic soils groups (HSG)s within the Cottonwood Campground Wash Watershed. Hydrologic soil groups are based on estimates of runoff potential, with groups generally defined as follows:

Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet.

Group B. Soils having a moderate infiltration rate when thoroughly wet.

Group C. Soils having a slow infiltration rate when thoroughly wet.

Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet.

24-hour rainfall depths were extracted at the project location from National Oceanic and Atmospheric Administration (NOAA) Atlas 14 Volume 1 Version 5, Precipitation-Frequency Atlas of the United States, Southwestern States (Bonnin et al., 2011).

The Simplified Peak Discharge Method then uses equation 402-7 in the NMDOT DDM to estimate peak discharge:

Qp = A* Q* qu

Where:

Qp = peak discharge, cfs

A = drainage area, acres

Q = direct runoff, inches qu = unit peak discharge, cfs/acre-inch

Unit peak discharge is estimated from Table 404-1 in the NMDOT DDM and is based on the estimated time of concentration, which is the time it takes for water to flow from the most hydraulically distant point in the watershed to the design point. Time of concentration estimates were based on the Upland (velocity) Method for the un-gullied portion of the watershed and then the Kirpich Equation for the gullied portion based on Table 402-6 in the NMDOT DDM. The upland method was used for the sheet flow (~250 feet) and shallow concentrated flow (~600 feet) portions of the velocity regimes and the Kirpich equation was used for the gullied portion (~10,600 feet and greater). The gullied portion was broken into three segments due to the cliffs https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/soils/survey/geo/?cid=nrcs142p2_053620 https://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx

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Recommendations Report located in the middle of the watershed. Lumping the cliffs into a single gullied flow estimate would artificially over represent the slope influence of the cliffs. Figure 2-3 presents the drainage areas and time of concentration used for the estimations of peak discharge. Appendix B provides the calculations used for Simplified Peak Discharge Method. Given that peak flow calculations were greatest at the Upper Limit Design point, the flow rates at this location were used throughout. Table 1 summarizes the flow rates used for this analysis.

Table 1. Peak Discharges Used for the Proposed Bridge over the Cottonwood Campground Wash

Flood Return

Annual Flood Exceedance Probability

Peak Discharge (cfs)

100-yr 1% 267 50-yr 2% 217 25-yr 4% 172 10-yr 10% 119 5-yr 20% 85 2-yr 50% 47

The BOR 2017 report used regional regression equations via the USGS StreamStats program (https://streamstats.usgs.gov/ss/). These produced much greater flows compared to the Simplified Peak Discharge Method. However, the NMDOT DDM does not allow their use for drainage design projects. Reasons the regional regression equations produce much higher flows include the following:

A significant amount of the soils within the watershed have high infiltration rates represented by HSGs A (15 percent) and B (24 percent) (Figure 2-5). Soil type is not accounted for in the regression equations.

There is a cliff that splits the watershed. The regression equations represent the watershed slope as one lumped parameter that will over represent the elevation change reflected in the cliffs. The Simplified Peak Discharge Method accounts for the steep flow in the cliffs that then flatten out towards to lower end of the watershed.

The regression equations do not account for cover type.

https://streamstats.usgs.gov/ss/

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Figure 2-1. Looking Northwest uphill into the Watershed, Cliffs can be seen to the Right

Figure 2-2. Looking Northeast uphill into the Watershed, Cliffs can be seen to the Left

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Figure 2-3. Hydrologic Assumptions for the Simplified Peak Discharge Method

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Figure 2-4. Hydrologic Land Cover Assumptions for the Simplified Peak Discharge Method

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Figure 2-5. Hydrologic Soil Groups for the Cottonwood Campground Wash Watershed

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2.2 San Juan River

Given the proximity of the proposed roadway bridge for the Cottonwood Campground Wash to the San Juan River, coincident flow in the San Juan River must be considered both as a downstream backwater condition to local Cottonwood Campground Wash flows and to determine if the San Juan River itself may have the potential of backing up to the proposed bridge location.

The drainage area for the San Juan River to the Cottonwood Campground is approximately 3,230 square miles, with flows regulated by the Navajo Dam. There is a United States Geological Survey (USGS) stream gage (USGS Station Number: 09355500; Station Name: San Juan River near Archuleta, NM) located 1.4 miles downstream of Cottonwood Campground at Archuleta that was active from 1955 to 2015. Given that the drainage area is greater than 10 square miles and that there is a gage in the project vicinity, a gage analysis was performed per the NMDOT DDM (p. 4-6).

The USGS did not develop stream flow statistics and did not publish flood characteristics for gage 09355500. Hydrology for the gage was therefore estimated by developing flood characteristic using the United States Army Corps of Engineers (USACE) Hydrologic Engineering Center's (HEC) Statistical Software Package (HEC-SSP) (version 2.2) based on the flow data on record at the gage. HEC-SSP is used to develop flood flow frequency analysis based on Bulletin 17B (Interagency Advisory Committee on Water Data, 1982) and Bulletin 17C (England, et al., 2018). The output from the HEC-SSP analysis is presented in Appendix C.

These flows were then adjusted to Cottonwood Campground using Equation 3, p. 11 in the USGS Scientific Investigations Report (SIR) 2008–5119, Analysis of the Magnitude and Frequency of Peak Discharge and Maximum Observed Peak Discharge in New Mexico and Surrounding Areas (Waltemeyer, 2008). Flow rates estimated for the San Juan River at Cottonwood Campground are summarized in Table 2 and the resulting 100-year water levels compared reasonably well with the FEMA Zone A boundary.

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Table 2. Peak Discharges Estimated for the San Juan River at Cottonwood Campground

Flood Return

Annual Flood Exceedance Probability

Peak Discharge of the San Juan River Estimated at the Cottonwood Campground

100-yr 1% 14,301 50-yr 2% 12,147 25-yr 4% - 10-yr 10% 7,517 5-yr 20% 5,653 2-yr 50% 3,198

3 Hydraulics A one-dimensional (1D) hydraulic model was developed using the USACE HEC River Analysis System (HEC-RAS), version 5.0.7. For this analysis, the following model scenarios were developed:

Existing Cottonwood Campground Wash (low flow crossing) Existing San Juan River at Cottonwood Campground Proposed Bridge Over the Cottonwood Campground Wash

3.1 Model Terrain

The model terrain is based on a ground survey performed in September 2020 and supplemented with LiDAR collected in 2018 and published in 2020. Existing conditions survey for the low flow crossing and channel cross sections was performed by Woolpert, Inc. and included the following:

Survey of the Cottonwood Campground Wash approximately 1,200 feet upstream and 1,065 feet downstream (to the San Juan River) of the existing low flow crossing with a total of 10 cross-sections surveyed.

Survey of the San Juan River 2,850 feet upstream and 800 feet downstream of the Cottonwood Campground Wash confluence, with a total of 4 cross-sections surveyed.

Additional spot elevations in the vicinity of the Cottonwood Campground and the existing roadways.

The survey data and the model are in the State Plane New Mexico West Harn North American Datum 1983 (feet) horizontal datum and all elevations are referenced to NAVD 88 (feet) vertical datum. The 2018 LiDAR had to be projected from the Universal Transverse Mercator (UTM) North American Datum 1983 (meter) to the project State Plane datum.

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3.2 Model Parameters

Model extents were based on the Woolpert survey, with the furthest upstream modeled cross-section corresponding to the furthest upstream surveyed cross-section for both the Cottonwood Campground Wash and the San Juan River.

Surface roughness, represented by the Manning’s roughness coefficient, were assigned to the channels and banks of each cross section in GIS. Values were estimated from “Open Channel Hydraulics” (Chow, 1959). This is the same reference used in the NMDOT DDM as well as the HEC-RAS Hydraulic Reference Manual (USACE, 2016). The exception is that the Cottonwood Campground Wash, based on the BOR 2017 report, was assigned a roughness value of 0.018 for a sandy bottom river with no vegetation in the channel in the upper reaches and increased to

0.03 for a grassy channel at the downstream-most portion of the wash. (Figure 3-1, Figure 3-2).

The 0.018 for a sandy bed channel is also consistent with the Scientific Investigations Report 2006–5108 (Phillips et. al., 2007). The San Juan River was assigned a roughness value of 0.05 for a rocky bottom river that is clean with some pools and shoals (Figure 3-3).

Given the varied roughness in the floodplains between scattered shrub, dense shrub, and dense trees, numerous Manning’s values were assigned.

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Figure 3-1. Photograph of the Cottonwood Campground Wash Upstream of the Existing Low Flow Crossing (Typical) (taken 9/23/20 looking upstream)

Figure 3-2. Photograph of the Cottonwood Campground Wash Downstream of the Existing Low Flow Crossing (Typical) (taken 9/23/20 looking downstream)

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Figure 3-3. Photograph of the San Juan River Looking South across the Channel (Typical) (taken 9/22/20)

The Cottonwood Campground Wash is generally confined for most of its length through the campground upstream of the existing crossing with a slope of approximately 2 percent. A sand berm was constructed along the east side of the channel within the campground. A channel contraction, roughly 100 feet in length, exists approximately 700 feet upstream of the existing crossing with a five-foot-high sandstone vertical drop in grade (Figure 3-4). Above this drop and through the contraction the channel is at a grade of about 5 percent (Figure 3-5). Upstream of this contraction the channel widens again with a slope of approximately 2 percent.

At the existing low flow crossing, a large break in slope exists along with a 3-foot drop from the bed elevation upstream of the crossing to the crossing elevation and represents a localized low point in the profile.

Downstream of the existing low flow crossing, the channel widens with a flow split several hundred feet downstream of the existing crossing. Berms have been constructed on either side of the channel downstream of the crossing and these are continuous after the flow split down to the confluence with the San Juan River.

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For estimating flow depths, the model was executed under steady-state, sub-critical flow conditions with critical depth as the minimum possible depth if reached at a given cross section and flow rate. Critical flow depth is a good approximation of flow depth for steep, natural channels with mobile beds, which may oscillate between sub critical, critical, and supercritical at flood flows (Grant 1997). This assumption is also consistent with the BOR 2017 report.

However, there are numerous locations of critical flow along the channel upstream of the existing low flow crossing, an observation also noted in the BOR 2017 report. Given these channel conditions, there are several hydraulic jumps throughout the modeled area and required running a mixed flow regime for scour calculations and also requiring several more cross-sections then were originally surveyed. These cross-sections were developed based on the 2018 LiDAR. A total of 113 cross-sections were cut for the modeling with an average spacing of 22 channel feet. Photos taken from the existing low flow crossing are presented in Figure 3-6 (upstream) and Figure 3-7 (downstream). The cut cross-section locations are shown in Figure 3-8. The downstream boundary condition was set at the 2-year water surface elevation of the San Juan River.

The proposed condition model reflects the proposed bridge location along a new roadway alignment. The proposed bridge will be prefabricated steel with no piers and 2.75 foot horizontal to 1-foot vertical abutments at either side. The spacing between abutments will be 50 feet across the channel bottom. The low chord is based on the greater between the modeled 25-year WSE plus two feet of freeboard and 6-feet, which it the height required to move a small grader through the bridge opening. The total width of the proposed bridge is 82 feet wide and it will tie into the existing road.

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Figure 3-4. Photograph of the 5 Foot Sandstone Drop 600 Feet Upstream of the Existing Low Flow Crossing (taken 9/23/20 looking upstream)

Figure 3-5. Photograph of the Channel Contraction Upstream of the Existing Low Flow Crossing and Immediately Upstream of the Sandstone Drop (taken 9/23/20 looking upstream)

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Figure 3-6. Photograph of the Cottonwood Campground Wash (taken 9/23/20 looking upstream from the Existing Low Flow Crossing)

Figure 3-7. Photograph of the Cottonwood Campground Wash (taken 9/23/20 looking downstream from the Existing Low Flow Crossing)

Figure 3-8. HEC-RAS Cross Sections for the Cottonwood Campground Wash

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The San Juan River is a fairly flat rocky bottom channel. A total of 15 cross-sections were cut for the modeling with an average spacing of 260 channel feet. The cut cross-section locations are shown in Figure 3-9. The downstream boundary condition was set at a normal depth of 0.004 foot per foot based on the energy grade slope of the existing channel.

Figure 3-9. HEC-RAS Cross Sections for the San Juan River at Cottonwood Campground

The peak discharges presented in Table 1 and Table 2 were introduced at furthermost upstream cross sections of their respective models as single sets of steady state flows.

3.3 Model Results

3.3.1 San Juan River

The results of the 1D HEC-RAS model for 2-year flows in the San Juan River were used to set the downstream boundary condition of the Cottonwood Campground Wash. Model results were extracted at the Cottonwood Campground Wash confluence at cross-section 1004 (Figure 3-9).

These model results are presented in Table 3. As stated in section 1.3, the 2-year WSE (elevation 5678.23) was used as the backwater condition for the Cottonwood Campground Wash.

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Table 3. Model results for the San Juan River at the Cottonwood Campground Wash Confluence

Flood Return

Annual Flood Exceedance Probability

Water Surface Elevation in the San

Juan River at Cross-Section 1004

100-yr 1% 5683.05 50-yr 2% 5682.36 10-yr 10% 5680.57 5-yr 20% 5679.68 2-yr 50% 5678.23

3.3.2 Cottonwood Campground Wash

Results from the HEC-RAS 1D model for the Cottonwood Campground Wash were evaluated using a sub-critical flow regime to evaluate the hydraulic and energy grade lines under the proposed bridge. This solution provides the most conservative hydraulic grade lines for bridge opening design.

The proposed bridge was sized to provide at least six feet of clearance to allow for maintenance within the channel. The proposed bridge was then evaluated for the 25-year flow (4% AEP) with 2 feet of freeboard, with freeboard defined as the vertical clearance between the design-flood water surface and the low chord of the bridge superstructure based on the criteria discussed in section 1.3. The reference datum for measuring the freeboard is the computed WSE at the upstream face of the bridge. The 50- and 100-year flows are also contained under the bridge low chord. Table 4 summarizes the WSEs and resulting freeboard at the upstream face of the proposed bridge.

The 25-year (4% AEP) energy grade line is at elevation 5687.9, so the bridge abutment benches should be above this elevation, which is consistent with preliminary design. The 50-year (2% AEP) energy grade line is at elevation 5688.08, so the riprap depth should extend above this elevation and be at a minimum depth of 1.4 feet. Table 4 tabularizes these energy grade line results.

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Table 4. Modeled Water Surface Elevation at the Upstream Face of the Proposed Bridge

Flood Return

Annual Flood Exceedance Probability

Water Surface

Elevation (ft)

Flow Depth (ft)

Channel Invert Elevation:

5686.17 ft

Freeboard (ft) Bridge Low Chord Elevation: 5693.50

Energy Grade Line Elevation (ft)

500-yr1 0.2% 5688.41 2.24 5.09 5688.68 100-yr1 1% 5688.07 1.9 5.43 5688.26 50-yr1 2% 5687.92 1.75 5.58 5688.08 25-yr1 4% 5687.77 1.6 5.73 5687.9 10-yr1 10% 5687.57 1.4 5.93 5687.66 5-yr1 20% 5687.41 1.24 6.09 5687.48 2-yr1 50% 5687.17 1.0 6.33 5687.21

1 Model results taken at upstream face of bridge with a sub-critical flow regime

Based on the criteria discussed in section 1.3, the check flood for water surface increases is the greater between the 50-year flood (2% AEP) and the overtopping flood. The 500-year flood (0.2% AEP) is not projected to overtop the bridge, therefore the 50-year flood (2% AEP) was evaluated.

Modeling indicates slight increases in the WSE extending 120 feet upstream and immediately downstream of the proposed bridge. Table 5 provides the 50-year (2% AEP) WSEs for the existing and proposed conditions models as well as the differences between the two.

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Table 5. 50-year (2% AEP) Water Surface Elevations

Cross Section Existing WSE

(ft) Proposed WSE

(ft) Difference 1454 5692.21 5692.21 0 1427 5691.72 5691.72 0 1405 5691.31 5691.31 0 1382 5690.87 5690.87 0 1360 5690.4 5690.4 0 1337 5689.95 5689.95 0 1320 5689.46 5689.48 0.02 1299 5689.15 5689.18 0.03 1274 5688.78 5688.79 0.01 1259 5688.51 5688.52 0.01 1252 5688.34 5688.43 0.09 1241 5688.13 5688.52 0.39 1234 5687.72 5688.54 0.82

1203 Proposed Bridge over the Cottonwood Campground Wash 1172 5686.98 5687.01 0.03 1145 5686.55 5686.55 0 1109 5686.6 5686.6 0 1065 5686.61 5686.6 -0.01 1043 5686.56 5686.56 0 1030 5686.55 5686.55 0 1006 5686.54 5686.54 0

994 5686.51 5686.51 0 982 5686.48 5686.48 0 966 5686.41 5686.41 0

3.4 Scour

A scour analysis was performed for the Cottonwood Campground Wash at the proposed bridge location. The scour analysis is intended to inform the structural and countermeasure design of the crossing. Results from the HEC-RAS 1D model were used using a mixed flow regime that allows the flow to become super critical. This solution provides the most conservative velocities for scour design.

Methodologies presented in the FHWA Hydraulic Engineering Circular No. 18 Evaluation of Scour at Bridges (HEC-18) were used for scour analysis based on direction in the NMDOT DDM. Based on the criteria discussed in section 1.3, stability and scour analysis are based on 50-year flows (2% AEP) with a check flood based on 100-year flows (1% AEP).

At the project site, the following scour components were evaluated:

Contraction Scour Abutment Scour

A desktop review of historic aerial photography indicated a stable wash and no identifiably active geomorphic processes. Furthermore, the wash profile did not indicate that downstream nick points

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3.4.1 Contraction Scour

Contraction scour represents short-term channel degradation caused by the contraction of flow area through a restricted bridge opening. Contraction scour was calculated using the HEC-18 Contraction Scour approach as directed in the NMDOT DDM. Contraction scour was calculated for the 50- and 100-year flows. The calculation was performed using the live-bed condition since channel velocity was determined to be greater than the critical velocity for both flood events. Table 6 summarizes the contraction scour results. Given that the proposed bridge has minimal contraction for these flow depth, the associated live-bed contraction scour is zero.

Table 6. Contraction Scour Results

Flood Return Annual Flood Exceedance Probability

Live-Bed Contraction Scour (ft)

50-yr 2% 0.0 100-yr 1% 0.0

3.4.2 Abutment Scour

Abutment scour is used to determine bury depths for abutment foundations. Abutment scour was calculated using the NCHRP 24-20 approach as documented in HEC-18 and as specified in the NMDOT DDM. Abutment scour was calculated for the 50- and 100-year flows. The abutment scour results can be found in Table 7.

Table 7. Abutment Scour Results

Flood Return Annual Flood Exceedance Probability

Abutment Scour depth (ft)

Abutment Scour depth with a 1.5

Factor of Safety (ft) 50-yr 2% 0.16 0.24

100-yr 1% 0.16 0.24

A riprap pad surrounding the abutments should be provided as protection from localized surface runoff. Riprap was sized based on methods described in Bridge Scour and Stream Instability Countermeasures: Experience, Selection, and Design Guidance, Volume 2, Third Edition (HEC-

23) and as specified in the NMDOT DDM (FHWA, 2009). Table 8 summarized the riprap recommendations for the proposed bridge. The required riprap depth is 1.5 feet. It should be angular riprap, Class 3.

Table 8. Riprap Recommendations for Bridge #3807

Flood Return Annual Flood Exceedance Probability

Rip Rap Class

D50 (ft)

D100 (ft)

Rip Rap Thickness

(ft) 50-yr 2% Facing 0.95 1.3 1.5

Folsom South Trail Improvements Ph II 26 Central Federal Lands Highway

Recommendations Report

100-yr 1% Facing 0.95 1.3 1.5

3.5 Contraction Plunge Pool

There is an existing natural plunge pool located approximately 600 feet upstream of the existing low water crossing which will be armored with grouted riprap as part of this project as well as armoring of the 100-foot channel contraction downstream of this drop. Results from the HEC- RAS 1D model were used to determine the velocities and flow depths to the plunge pool. Results from the HEC-RAS 1D model were evaluated using a mixed flow regime that allows the flow to become super critical. This solution provides the most conservative velocities for riprap placement.

4 Conclusion The purpose of this report is to provide a channel hydraulic analysis and design of the proposed bridge over the Cottonwood Campground Wash, which includes: selection of hydrologic peak discharges, proposed design hydraulic modeling, flood profile and floodplain analysis, and scour analysis.

Based on the hydraulic analysis, the proposed bridge opening passes the 25- and 50-year (4% and 2% AEP, respectively) with over 5.5 feet of freeboard under the proposed low chord. There is a minimal rise in water surface elevations between the existing and proposed conditions that only extend approximately 120 feet upstream of the proposed bridge.

In order to prevent erosion at the face of the abutments, riprap is recommended at the upstream and downstream abutments. The riprap should extend 25 feet past the abutment wall both upstream and downstream, with a 4.5 foot depth at the tie in (3 times the 1.5 foot riprap depth).

Since the abutment scour is minimal, the depth of riprap should be 1.5 feet at locations other than the tie in point.

The conclusions and recommendations in this report are based on the conditions of the project site and the associated watershed at the time of this study. Any modifications to the site, man-made or natural, could alter the analysis, findings, and recommendations contained herein and could invalidate the analysis, findings, and recommendations. Site conditions, completion of upstream or downstream projects, upstream or downstream land use changes, climate changes, vegetation changes, maintenance practice changes, or other factors may change over time.

Additional analysis or updates may be required in the future as a result of these changes.

Folsom South Trail Improvements Ph II 27 Central Federal Lands Highway

Recommendations Report

5 References Bonnin, G., D. Martin, S. Pavlovic, B. Lin, T. Parzybok, M. Yekta, D. Riley. 2004, Revised 2011.

NOAA Atlas 14 Volume 1 Version 5, Precipitation-Frequency Atlas of the United States, Semiarid Southwest. NOAA, National Weather Service. Silver Spring, MD.

http://hdsc.nws.noaa.gov/hdsc/pfds

Bureau of Reclamation. 2017. Cottonwood Campground Low Water Crossing Appraisal Design Report, Technical Memorandum No. 1928-CC-8150-APP-2017-9.

Chow, V.T. 1959. Open Channel Hydraulics. McGraw-Hill Book Company, NY.

Grant, Gordon E. 1997. “Critical Flow Constrains Flow Hydraulics in Mobile- Bed Streams: A New Hypothesis.” Water Resources Research 33(2): 349– 58.

http://doi.wiley.com/10.1029/96WR03134.

England, J.F., Cohn, T.A, Faber, B.A, Stedinger, J.R., Thomas, W.O., Veilleus, A.G….. Mason, R.R.

2018. Guidelines for Determining Flood Flow Frequency, Bulletin 17C. Washington D.C. U.S.

Department of the Interior.

Federal Emergency Management Agency. Flood Insurance Study for San Juan County, New Mexico and Incorporated Areas. Flood Insurance Study Number 35045C0800F. Effective Date August 5, 2010.

Federal Highway Administration. 2009. Bridge Scour and Stream Instability Countermeasures:

Experience, Selection, and Design Guidance (Volume 2). Third Edition. Publication No.

FHWA-NHI-09-112. Hydraulic Engineering Circular No. 23.

Federal Highway Administration. 2009. Urban Drainage Design Manual. Third Edition. Publication No. FHWA-NHI-10-009. Hydraulic Engineering Circular No. 22. Revised 2013.

Federal Highway Administration. 2012. Evaluating Scour at Bridges. Fifth Edition. Publication No.

FHWA-HIF-12-003. Hydraulic Engineering Circular No. 18.

Federal Highway Administration. December 2012. Federal Lands Highway Division Project Development and Design Manual, Chapter 7 Hydrology and Hydraulics.

Interagency Advisory Committee on Water Data. 1982. Guidelines for Determining Flood Flow Frequency, Bulletin 17B. Reston, VA. U.S. Geological Survey.

New Mexico DOT Drainage Design Manual, Section 607.3.2 (Smith Engineering Company et al.

July 2018. Drainage Design Manual New Mexico Department of Transportation).

NRCS, June 1986, “TR-55, Urban Hydrology for Small Watersheds”, Table 2-2a, p. 2-5.

https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1044171.pdf

Phillips, J., S. Tadayon. 2007. Selection of Manning’s Roughness Coefficient for Natural and Constructed Vegetated and NonVegetated Channels, and Vegetation Maintenance Plan http://hdsc.nws.noaa.gov/hdsc/pfds http://doi.wiley.com/10.1029/96WR03134 https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1044171.pdf

Folsom South Trail Improvements Ph II 28 Central Federal Lands Highway

Recommendations Report

Guidelines for Vegetated Channels in Central Arizona. Scientic Investigations Report 2006– 5108.

United States Army Corps of Engineers (USACE). 2016. HEC-RAS River Analysis System Hydraulic Reference Manual, Version 5.0.

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.9, 11-12, 51

Appendix A

FEMA FIRM

National Flood Hazard Layer FIRMette

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

Ü

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 DepthZone 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 mileZone X

Future Conditions 1% Annual Chance Flood HazardZone X

Area with Reduced Flood Risk due to Levee. See Notes.Zone X

Area with Flood Risk due to LeveeZone D

NO SCREENArea of Minimal Flood HazardZone X

Area of Undetermined Flood HazardZone 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 2/18/2021 at 12:47 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

B 20.2

The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location.

1:6,000

107°41'5"W 36°48'50"N

107°40'27"W 36°48'22"N

Basemap: USGS National Map: Orthoimagery: Data refreshed October, 2020

JECHRIST

Rectangle

JECHRIST

Callout Project Location

Appendix B Hydrologic Calculations for the Cottonwood Campground Wash

Project: Job No:

Subject: Computed: JAC Date: 12/3/2020 Task: Checked: Date:

L:\jechrist\HutchinsonUtility\Comp Sheet.doc

Worksheet for computation of time of travel according to the New Mexico DOT Drainage Design Manual Reference: Smith Engineering Company et al. July 2018. Drainage Design Manual New Mexico Department of Transportation

NRCS Simplified Peak Discharge Method

Watershed Drainage

Area*

Area Weighted

Curve Number**

Time of Concentration*

Unit Peak

Discharge*** Watershed

2-Year Rainfall Depth

5-Year Rainfall Depth

10-Year Rainfall Depth

25-Year Rainfall Depth

50-Year Rainfall Depth

100-Year Rainfall Depth

500-Year Rainfall Depth

(acres) (min) (cfs/ac-in) (in) (in) (in) (in) (in) (in) (in) A CN TC qu P2 P5 P10 P25 P50 P100 P500

Watershed_LowerLimit 525.2 79.6 86.0 0.42 Watershed_LowerLimit 1.31 1.65 1.92 2.3 2.6 2.91 3.68 Watershed_FutureBridge 483.0 80.4 82.4 0.43 Watershed_FutureBridge 1.31 1.65 1.92 2.3 2.6 2.91 3.68 Watershed_UpperLimits 462.6 80.9 75.2 0.47 Watershed_UpperLimits 1.31 1.65 1.92 2.3 2.6 2.91 3.68

* Extracted out of GIS ** Geoprocessed using GIS tools *** Rounded down to the nearest 2 minutes ****Based on trendlinearound nearest data points in Table 404-1

Direct Runoff

Q = (P-(200/CN)+2)^2)/(P + 800/CN)-8) eq. 404-1 Watershed

2-Year Direct Runoff

5-Year Direct Runoff

10-Year Direct Runoff

25-Year Direct Runoff

50-Year Direct Runoff

100-Year Direct Runoff

500-Year Direct Runoff

Q = direct runoff, inches Q2 Q5 Q10 Q25 Q50 Q100 Q500 P = 24-hour rainfall depth, inches Watershed_LowerLimit 0.2 0.3 0.5 0.7 0.9 1.2 1.8 CN = Runoff Curve Number Watershed_FutureBridge 0.2 0.4 0.5 0.8 1.0 1.2 1.8

Watershed_UpperLimits 0.2 0.4 0.6 0.8 1.0 1.2 1.8

Peak Discharge

Qp = A* Q* qu eq. 402-7

Watershed 2-Year Flow

5-Year Peak

Discharge Flow

10-Year Peak

Discharg Flow

25-Year Peak

Discharg Flow

50-Year Peak

Discharg Flow

100-Year Peak

Discharg Flow

500-Year Peak

Discharg Depth

Discharge (Qp100) to

Area (ac) Ratio Qp = peak discharge, cfs A = drainage area, acres Qp2 Qp5 Qp10 Qp25 Qp50 Qp100 Qp500 Q = direct runoff, inches Watershed_LowerLimit 42 77 110 162 207 255 386 0.49 qu = unit peak discharge, cfs/acre-inch Watershed_FutureBridge 44 79 111 162 206 253 380 0.52

Watershed_UpperLimits 47 85 119 172 217 267 398 0.58

Time of concentration

Computation CFLHD TO86 NM Cottonwood 10241600 CFLHD TO86 NM SJU Cottonwood Task 6.0 Hydraulics Local Hydrology

NOAA 24-Hours Rainfall Depth

Direct Runoff, Q (Equation 404-1)

Peak Discharge, Qp (Equation 404-2)

(in)

(cfs)

Subject: Computed: JAC Date: 12/3/2020 Task: Checked: Date:

L:\jechrist\HutchinsonUtility\Comp Sheet.doc

Worksheet for computation of time of travel according to the New Mexico DOT Drainage Design Manual Reference: Smith Engineering Company et al. July 2018. Drainage Design Manual New Mexico Department of Transportation

Summary Watershed TC (hr) TC (min) Watershed_LowerLimit 1.43 85.96 Watershed_FutureBridge 1.37 82.38 Watershed_UpperLimits 1.25 75.17

2-Year, 24-hour rainfall: 1.31 in

Watershed Flow Condition Flow Characteristic Reach Length Upstream Elev. Downstream Elev Drop Slope Manning's Channel Average Travel Travel (Surface) (Surface) n Slope Velocity Time Time

(ft) (ft) (ft) ft/ft (ft/s) (hr) (min) Watershed_LowerLimit Sheet Range (natural) 253 6465 6460 5 0.0197 0.13 - 0.48 28.9 Sheet

Shallow Concentrated Short Grass Pasture 599 6460 6425 35 0.0584 - - 1.7 0.10 5.9 Shallow Concentrated Channel Gullied Flow 4093 6425 6240 185 0.0452 0.045 0.26 15.5 Kirpich Equation Channel Gullied Flow 1040 6240 5900 340 0.3268 0.327 0.04 2.5 Kirpich Equation Channel Gullied Flow 5910 5900 5713.7 186.3 0.0315 0.032 0.39 23.7 Kirpich Equation Channel Gullied Flow 1459 5713.7 5683 30.7 0.0210 0.021 0.16 9.4 Kirpich Equation Total Tt 1.43 86.0

Watershed_FutureBridge Sheet Range (natural) 253 6465 6460 5 0.0197 0.13 - 0.48 28.9 Sheet Shallow Concentrated Short Grass Pasture 599 6460 6425 35 0.0584 - - 1.7 0.10 5.9 Shallow Concentrated Channel Gullied Flow 4093 6425 6240 185 0.0452 0.045 0.26 15.5 Kirpich Equation Channel Gullied Flow 1040 6240 5900 340 0.3268 0.327 0.04 2.5 Kirpich Equation Channel Gullied Flow 5910 5900 5713.7 186.3 0.0315 0.032 0.39 23.7 Kirpich Equation Channel Gullied Flow 925 5713.7 5686.5 27.2 0.0294 0.029 0.10 5.8 Kirpich Equation Total Tt 1.37 82.4

Watershed_UpperLimits Sheet Range (natural) 253 6465 6460 5 0.0197 0.13 - 0.48 28.9 Sheet Shallow Concentrated Short Grass Pasture 599 6460 6425 35 0.0584 - - 1.7 0.10 5.9 Shallow Concentrated Channel Gullied Flow 4093 6425 6240 185 0.0452 0.045 0.26 15.5 Kirpich Equation Channel Gullied Flow 1040 6240 5900 340 0.3268 0.327 0.04 2.5 Kirpich Equation Channel Gullied Flow 5467 5900 5727.7 172.3 0.0315 0.032 0.37 22.3 Kirpich Equation Total Tt 1.25 75.2

(Surface)

Computation CFLHD TO86 NM Cottonwood Campground 10241600 CFLHD TO86 NM SJU Cottonwood Task 6.0 Local Hydrology Time of concentration calcuations

For Sheet Flow: Tt = 0.007*(n*L)0.8/(P20.5*s0.4) eq. 402-7 L = sheet flow length, ft n= Manning’s roughness coefficient- Table 402-7

P2 = 2-year, 24-hour rainfall, in.

S = slope of land surface, ft/ft

For Paved Shallow Concentrated Flow: V = 20.3282*S^0.5 (empirical) Table 402.8 For Short Grassed Concentrated Flow: V = 6.962*S^0.5 (empirical)

Gullied Flow Time of Concentration by the Kirpich Equation

TC = 0.0078 * L0.77*S-.385 TC = Time of Concentration, minutes eq. 402-8 L = maximum length of water travel, ft S = slope of land surface, ft/ft

NMDOT DrainaJuly 2018 Page 4—86

Reference: Smith Engineering Company et al. July 2018. Drainage Design Manual New Mexico Departm qu hours min cfs/ac-in

0.167 10 1.900

0.200 12 1.730

0.233 14 1.650

0.267 16 1.500

0.300 18 1.350

0.333 20 1.280

0.367 22 1.180

0.400 24 1.100

0.433 26 1.040

0.467 28 0.970

0.500 30 0.930

0.533 32 0.890

0.567 34 0.848

0.600 36 0.805

0.633 38 0.778

0.667 40 0.752

0.700 42 0.725

0.733 44 0.688

0.800 48 0.650

0.867 52 0.623

0.900 54 0.595

1.000 60 0.550

1.500 90 0.395

2.000 120 0.313

2.500 150 0.260

3.000 180 0.225

3.500 210 0.202

4.000 240 0.178

4.500 270 0.163

5.000 300 0.148

5.500 330 0.138

6.000 360 0.128

6.500 390 0.122

7.000 420 0.115

7.500 450 0.108

8.000 480 0.100

8.500 510 0.095

9.000 540 0.090

9.500 570 0.087

10.000 600 0.083

Tc

Source: Soil Conservation Service, 1973, revised by Luther McDougal, and Calvin Jackson, 1973, updated by Larry Goertz, February 1985, updated by Roger Ford, 2014, “Peak Rates of Discharge for Small Watersheds, Chapter 2, Engineering Field Manual for Conservation Practices”.

Source: Soil Conservation Service, 1973, revised by Luther McDougal, and Calvin Jackson, 1973, updated by Larry Goertz, February 1985, updated by Roger Ford, 2014, “Peak Rates of Discharge for Small Watersheds, Chapter 2, Engineering Field Manual for Conservation Practices”.

y = 0.345ln(x) + 1.9563 R² = 0.9939

0.200

0.250

0.300

0.350

0.400

0.450

0.500

0.550

0.600

40 50 60 70 80 90 100 110 120 130 Tc (hours)

Unit Peak Discharge, qu (cfs/acin)

Appendix C Hydrologic Calculations for the San Juan River

File: SAN_JUAN_RIVER_NEAR_ARCHULETA.rpt, Page: 1

Bulletin 17C (Java) Frequency Analysis 13 Jan 2021 04:20 PM --- Input Data --- Analysis Name: SAN JUAN RIVER NEAR ARCHULETA Description: SAN JUAN RIVER NEAR ARCHULETA, NM Data Set Name: SAN JUAN RIVER NEAR ARCHULETA, DSS File Name: J:\10241600_CFLHD_TO86_NM_CottonwoodCG\model\Hydrology\SanJuan\HEC_SSP\SAN_JUAN_RIVER_NEAR_A DSS Pathname: /SAN JUAN RIVER/ARCHULETA, NM/FLOW-ANNUAL PEAK/01jan1900/IR-CENTURY/USGS/ Report File Name: J:\10241600_CFLHD_TO86_NM_CottonwoodCG\model\Hydrology\SanJuan\HEC_SSP\SAN_JUAN_RIVER_NEAR_ XML File Name: J:\10241600_CFLHD_TO86_NM_CottonwoodCG\model\Hydrology\SanJuan\HEC_SSP\SAN_JUAN_RIVER_NEAR_A Start Date:

End Date:

Skew Option: Use Station Skew Regional Skew: -Infinity Regional Skew MSE: -Infinity Plotting Position Type: Hirsch-Stedinger Upper Confidence Level: 0.05 Lower Confidence Level: 0.95 Display ordinate values using 1 digits in fraction part of value --- End of Input Data --- << EMA Representation of Data >>

SAN JUAN RIVER NEAR ARCHULETA,

| | Value | Threshold | | | Year Peak | Low High | Low High | Type | | 1955 6,680.0 | 6,680.0 6,680.0 | 1.0E-99 1.0E99 | Syst | | 1956 4,820.0 | 4,820.0 4,820.0 | 1.0E-99 1.0E99 | Syst | | 1957 18,900.0 | 18,900.0 18,900.0 | 1.0E-99 1.0E99 | Syst | | 1958 12,500.0 | 12,500.0 12,500.0 | 1.0E-99 1.0E99 | Syst | | 1959 2,800.0 | 2,800.0 2,800.0 | 1.0E-99 1.0E99 | Syst | | 1960 7,320.0 | 7,320.0 7,320.0 | 1.0E-99 1.0E99 | Syst | | 1961 4,620.0 | 4,620.0 4,620.0 | 1.0E-99 1.0E99 | Syst | | 1962 8,230.0 | 8,230.0 8,230.0 | 1.0E-99 1.0E99 | Syst | | 1963 1,340.0 | 1,340.0 1,340.0 | 1.0E-99 1.0E99 | Syst | | 1964 2,080.0 | 2,080.0 2,080.0 | 1.0E-99 1.0E99 | Syst | | 1965 6,500.0 | 6,500.0 6,500.0 | 1.0E-99 1.0E99 | Syst | | 1966 3,420.0 | 3,420.0 3,420.0 | 1.0E-99 1.0E99 | Syst | | 1967 1,890.0 | 1,890.0 1,890.0 | 1.0E-99 1.0E99 | Syst | | 1968 1,710.0 | 1,710.0 1,710.0 | 1.0E-99 1.0E99 | Syst | | 1969 2,060.0 | 2,060.0 2,060.0 | 1.0E-99 1.0E99 | Syst | | 1970 2,020.0 | 2,020.0 2,020.0 | 1.0E-99 1.0E99 | Syst | | 1971 2,720.0 | 2,720.0 2,720.0 | 1.0E-99 1.0E99 | Syst | | 1972 1,660.0 | 1,660.0 1,660.0 | 1.0E-99 1.0E99 | Syst | | 1973 5,620.0 | 5,620.0 5,620.0 | 1.0E-99 1.0E99 | Syst | | 1974 2,000.0 | 2,000.0 2,000.0 | 1.0E-99 1.0E99 | Syst | | 1975 2,840.0 | 2,840.0 2,840.0 | 1.0E-99 1.0E99 |…