Lake_Pueblo_FINAL_Hydraulics_Report.pdf

Submitted to:

US Department of Transportation Federal Highway Administration Central Federal Lands Highway Division 1200 West Dakota Avenue Lakewood, Colorado 80228

FINAL Hydraulics Report Lake Pueblo Road & Trail Improvements

CO FLAP 1099 (1)

AECOM Project Number 60336366 July 31, 2015

AECOM FINAL Hydraulics Report Lake Pueblo Road & Trail Improvements : CO FLAP 1099 (1)

TOC-ii

Table of Figures Figure 2-1. Lake Pueblo Road and Trail Improvements Location ................................................................................... 2-3 Figure 2-2. Dry Wash Creek Shared Use Bridge............................................................................................................ 2-3 Figure 2-3. Arkansas River Trail Bridge ......................................................................................................................... 2-4 Figure 2-4. Arkansas River/Spillway Roadway Bridge .................................................................................................... 2-4 Figure 2-5. CMP............................................................................................................................................................ 2-5 Figure 2-6. Metal End Sections with Debris ................................................................................................................... 2-5 Figure 2-7. Vegetated Ditches ....................................................................................................................................... 2-5 Figure 2-8. Scour at Bridge Abutments .......................................................................................................................... 2-5 Figure 2-9. Ponded Water ............................................................................................................................................. 2-5 Figure 2-10. 96” CMP with Sedimentation ..................................................................................................................... 2-5 Figure 2-11. CMP under Juniper Road .......................................................................................................................... 2-6 Figure 2-12. Fiber Roll Check Dam ............................................................................................................................... 2-6 Figure 2-13. 2-45” Elliptical CMP with Debris ................................................................................................................. 2-6 Figure 2-14. Irrigation Ditch ........................................................................................................................................... 2-6 Figure 2-15. Rutting of Trail ........................................................................................................................................... 2-6 Figure 2-16. Sediment Washing away Trail ................................................................................................................... 2-6 Figure 4-1 Existing and Proposed Water Surface Profile (HEC-RAS) ............................................................................. 4-2 Figure 4-2 Existing and Proposed Cross Section Upstream Face of the Bridge (HEC-RAS) ........................................... 4-2

List of Tables

Table 3-1. Comparison of Peak Flows at Dry Wash Creek Pedestrian Bridge Crossing ................................................. 3-2 Table 4-1. HEC-RAS Parameters .................................................................................................................................. 4-1 Table 4-2. Comparison of WSELs at Dry Wash Creek Trail Bridge at Cross Section 162.87 .......................................... 4-1 Table 4-3. Comparison of WSELs at Dry Wash Creek Trail Bridge at Cross Section 162.87 .......................................... 4-3

1-1

The Federal Lands Access Program (FLAP) is providing funding towards rehabilitation, restoration, and resurfacing (3R) projects. The scope of work for this project is to perform environmental, engineering, hydraulic, geotechnical, right-of-way, surveying, mapping, and project management services toward delivery of a 100% PS&E for the Federal Highway Administration (FHWA), Central Federal Lands Highway Division (CFL) for proposed improvements to 4.21 miles of roads and 13.21 miles of trails in the Colorado Parks and Wildlife (CPW) Lake Pueblo State Park in Pueblo County which is on the Bureau of Reclamations’(BOR) Pueblo Reservoir property.

This FINAL Hydraulics Report has been prepared to present a summary of the hydrologic analysis and hydraulic (H&H) design and decisions for this project.

1 Introduction

2-2

This project includes reconstruction of approximately 4.2 miles of roads and 13.2 miles of trails in the CPW Lake Pueblo State Park in Pueblo County, which is on the BOR Pueblo Reservoir Property. There are 4 segments of proposed improvements will be presented as schedules and options. In general, the proposed work by Schedules and Options is as follows:

Schedule A: Schedule A includes roadway work on Juniper Road and ALL trail work. The roadway work begins on Juniper approximately 2.69 miles east of the bridge over the railroad, where the Colorado Parks and Wildlife Phase I project ended, and continues all the way to the intersection with South Marina Road. This includes Juniper Road Bridge crossing of the Arkansas River. The design speed for this section is 35 mph. The schedule includes 3.61 miles of roadway. Schedule A also includes 10.43 miles of reconstructed trail to new colored 8’ concrete trail, 1.41 miles of new aggregate trail (crusher fines) along an existing 2-track alignment along the Arkansas River, and 1.2 miles of existing asphalt pathways that will be pulverized and compacted in place. Additionally Schedule A includes one new Pedestrian bridge at the Dry Wash; replacing the existing pedestrian bridge across the Arkansas River (east of Juniper Road); and reconstructing the bridge and pedestrian rails on the east edge of the Juniper Road bridge over the Arkansas River to provide a wider shoulder for pedestrian/bicycle access.

Option X: Option X begins on Juniper Road at the north end of the bridge over the Union Pacific (UP) railroad, and ends at the east approach of the Dry Wash Creek Bridge (beginning of Colorado Parks and Wildlife Phase I project, involving road improvements that are similar to what is proposed, but these improvements are already completed). This segment also includes North Marina Road from North Marina Road to the intersection with Juniper. This option totals approximately 1.69 miles. Design speeds are 25- 45 mph for Juniper, and 25 mph for North Marina Road. Option X includes bridge rail reconstruction at the UPRR overpass and the Juniper Road Bridge over the Dry Wash.

Option Y: Option Y roadway work includes all of Reservoir Road (0.66 miles). The design speed for both roads is 35 mph.

Option Z: Option Z roadway work includes all of South Marina Road (0.54 miles) from their intersections with Juniper Road to Highway 96. The design speed for both roads is 35 mph.

This project will include coordination with the CPW, Lake Pueblo State Park, BOR’s Pueblo Reservoir property.

Per the Scope of Work (SOW) and the Scoping Report, H&H analysis was conducted based on the following assumptions:

H&H analysis will be performed for the Arkansas River Trail Bridge and the Dry Wash Creek Trail Bridge.

Culvert and ditch improvements will be based on field observations and maintenance staff recommendations. The SOW details the following:

o Culvert replacement will be a minimum of 24” or equivalent diameter, whichever is greater o 1 Low Tail Water Crossing o 4-6 new culvert locations

However, as design progressed, H&H analysis of the Arkansans River Trail Bridge is not required as it is located downstream of the reservoir which has regulated flows. In addition, cross culverts are to remain in place, with provisions for culvert cleaning, relocation or additions at the discretion of the Contracting Officer (CO).

In February 2015, a 30% field review was conducted.

2 Project Summary

2-3

2.1 Project Location

The project area is located approximately 7 miles west of downtown Pueblo, Colorado. The route cuts across the state park from the southeast lake entrance off of Highway 96 to the northwest most lake entrance termination at South Nichols Road in the subdivision of Pueblo West (north park boundary).

Figure 2-1. Lake Pueblo Road and Trail Improvements Location

Provided by Map data © 2015 Google

2.2 Existing Drainage Features

There are three bridges within the project limits that will be impacted. These bridges span Dry Wash Creek and the Arkansas River. The Dry Wash Creek Bridge (Dry Wash) has a 36 ft wide and 98 ft long single spanned bridge. The bridge deck contains a shared use path and roadway separated by a concrete wall. There have been numerous safety concerns and issues with this configuration. See Figure 2-2 for more details.

Figure 2-2. Dry Wash Creek Shared Use Bridge

Begin Project

End Project

North Not to Scale

Dry Wash Creek Bridge

Arkansas River/ Spillway Bridge

2-4

The trail bridge spanning the Arkansas River is 7.3 ft (out to out) wide and 120 ft long pre-fabricated, single span bridge. This bridge is located downstream of the reservoir and has controlled flows.

Figure 2-3. Arkansas River Trail Bridge

The roadway bridge spanning the Arkansas River/Spillway is 36 ft (out to out) wide and 202 ft long double spanned bridge.

Figure 2-4. Arkansas River/Spillway Roadway Bridge

2-5

Drainage features include: corrugated metal pipe (CMP), metal end sections, vegetated ditches, and riprap. Most culverts lack outlet protection (metal end sections or riprap). Sediment transport was noted at culverts and in some areas, across the trail. Some culverts were full of debris and will need to be cleaned. There was evidence of minor structure damages as CMPs and end sections were crushed and will need to be replaced. Lack of runoff conveyance was evident as ponded water on the trail and gullies and rills across the trail were observed. See the Figures below for more information.

Figure 2-5. CMP

Figure 2-6. Metal End Sections with Debris

Figure 2-7. Vegetated Ditches

Figure 2-8. Scour at Bridge Abutments

Figure 2-9. Ponded Water

Figure 2-10. 96” CMP with Sedimentation

2-6

Figure 2-11. CMP under Juniper Road

Figure 2-12. Fiber Roll Check Dam

Figure 2-13. 2-45” Elliptical CMP with Debris

Figure 2-14. Irrigation Ditch

Figure 2-15. Rutting of Trail

Figure 2-16. Sediment Washing away Trail

3-1

Design was conducted with the following considerations.

3.1 Design Criteria

H&H analysis and design work associated with the proposed improvements are in accordance with the methods, guidelines, and criteria set forth with the Federal Lands Highway Project Development and Design Manual (FLH PDDM). A summary of the applicable criteria can be found in the Hydrologic and Hydraulic Criteria and Computation Methods Memorandum, in Appendix A.

A full H&H was not conducted for this project. Field reviews and design discussions between AECOM, CFL, and Park Staff determined that drainage improvements would be based on design needs and field observations (repair breaks in culverts and protect scoured areas).

3.2 Wetlands and Waters of the US

Wetlands have been identified along the project corridor. A wetland delineation survey of the project is in progress.

3.3 Cultural Resources

Cultural Resources has been completed and no resources have been identified within the existing road bed.

3.4 Future Land Use

Future land use is anticipated to remain the same as today.

3.5 Flood History

The project improvements lie with the Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map (FIRM) Panel with a Zone A designation (Panel 080147 0225B). Proposed trail improvements cross the Zone A three times and parallels the delineation for approximately 2 miles.

Flooding or roadway overtopping has not been noted within the project limits.

3.6 Hydrologic Soils

The soils within the project limits mainly consist of hydrologic soil group D. These soils have a very slow infiltration rate and have a high runoff potential.

3 Design Discussions

3-2

3.7 Hydrology

Hydrologic analysis was conducted for the crossing at Dry Wash Creek. Basin delineation was conducted using StreamStats, an online United States Geological Survey (USGS) application that implements regression equations to estimate peak flows. The drainage basin area was 9.06 square miles; therefore, regression equations were used to generate peak flows.

The regression equations considered were from the following sources:

USGS’s Regional Regression Equations for Estimation of Natural Streamflow Statistics in Colorado:

revised 2014 (SIR 2009-5136).

USGS’s Analysis of the Magnitude and Frequency of Floods in Colorado, 2000 (WRIR 99-4190)

Although the peak flows were more conservative, the latter publication had a lower standard of error, so those regression equations were used. See the Appendix for calculation and Table 3.1 for a comparison of peak flows.

Table 3-1. Comparison of Peak Flows at Dry Wash Creek Pedestrian Bridge Crossing

3.8 Bridge Analysis Approach

This project will impact three bridges and proposed improvements will be based on the following approach:

1. Dry Wash Creek Shared Use Bridge: Relocate shared use approximately 25 ft downstream of existing bridge. A full H&H analysis will occur to analyze impacts and assess scour countermeasures.

2. Arkansas River Trail Bridge: In kind replacement, except the width of the bridge will increase from 7.3 ft to 10 ft. This bridge is located downstream from the reservoir and the flows are regulated. With this, the proposed bridge low chord will be equal or higher than the existing bridge low chord and H&H analysis is not required. It is assumed that the existing bridge adequately conveys flows and that overtopping does not currently occur.

3. Arkansas River/Spillway Bridge: The only modifications proposed are to replace guardrail; therefore, H&H analysis is not required.

Storm Event (Year)

WRIR 99-4190

Q

(cfs)

WRIR 99-4190

Average Standard

Prediction of Error (%)

SIR 2009-5136

Q

(cfs)

SIR 2009-5136

Average Standard

Prediction of Error (%)

Comments

2 114 93 88.7 180 5 472 89 238 140 10 880 90 382 140 25 1732 92 659 140 50 2648 95 908 140 Design Storm

100 3857 96 1260 140 Check for “no-rise” 200 5429 98 2410 160 Design Scour 500 8165 100 2350 140

4-1

Following the 30%, the original SOW was modified to provide drainage improvements warranted by field observations or responding to roadway design improvements. H&H analysis for the Arkansas River Trail Bridge has been removed from the SOW.

4.1 Summary of Bridge Hydraulics for Dry Wash Creek Trail Bridge

Because of the numerous safety concerns and issues with this configuration, the proposed improvements will have the shared use path and the road separated, with the roadway widening on the existing bridge and the shared use path spanning Dry Wash Creek at a new location just south of the existing bridge. The new bridge location will be approximately 25 ft downstream of the existing bridge with the abutments located outside of the channel.

The US Army Corps of Engineers (USACE) Hydrologic Engineer Centers River Analysis System (HEC-RAS), Version 4.1.0 was used to determine bridge opening width and low chord placement. The following parameters used for analysis are summarized in Table 4-1.

Table 4-1. HEC-RAS Parameters

HEC-RAS determined the 2-, 5-, 10-, 25-, 50-, 100-, and 500-year water surface elevation (WSEL) at the bridge using the mixed regime. A total of five surveyed cross sections were used that covered approximately 40 ft upstream and 110 ft downstream of the proposed bridge. Two methods were used to determine proposed elevations. Although the abutments are outside of the main channel, HEC-RAS shows a significant change in WSEL through the bridge. When using a Lid (preferred modeling approach), there is negligible change in WSEL.

Table 4-2 provides a summary table of the existing and proposed WSEL at the upstream face of the bridge.

Table 4-2. Comparison of WSELs at Dry Wash Creek Trail Bridge at Cross Section 128.9776

4 Recommended Design

Parameter Value

Manning’s n Channel: 0.035, Banks: 0.045 Bridge Deck Width (ft) 10

Bridge Deck Thickness (ft) 1.5 Bridge Overtopping Elevation (ft) 4907.86

Low Chord Elevation (ft) 4906.36 Flow Regime Mixed

Return Period

(yr)

Discharge (cfs)

Existing

WSEL

(ft)

Proposed

WSEL

(ft)

Proposed Velocity

(fps)

Change in

WSEL

(ft)

Freeboard in WSEL using a

Lid (ft)

Comments

2 114.00 4899.33 4899.33 6.53 0 7.03 5 472.00 4900.24 4900.24 8.15 0 6.12 10 880.00 4900.86 4900.86 9.02 0 5.50 25 1732.00 4901.76 4901.77 10.23 0.01 4.59 50 2648.00 4902.38 4902.37 11.73 -0.01 3.99 Design Storm

100 3857.00 4902.95 4902.95 13.51 0 3.41 Floodplain Check 200 5429.00 4903.54 4903.54 15.59 0 2.82 Scour Check 500 8165.00 4904.24 4904.32 18.89 0.08 2.04

4-2

0 20 40 60 80 100 120 140 160

PedBridge Plan: 1) Exist 7/21/2015 2) Proposed 7/22/2015

Main Channel Distance (ft)

E le va tio n (ft

Legend

WS Q100 - Exist

WS Q100 - Proposed

WS Q50 - Proposed

WS Q50 - Exist

Ground

.0

.3

0.

8.

7.

1.

3.

River River Reach

0 100 200 300 400

PedBridge Plan: Proposed 7/22/2015 River = River Reach = River Reach RS = 128.9776

Station (ft)

E le va tio n (ft

Legend

WS Q100

WS Q50

Ground

Bank Sta

.045 .035 .045

The HEC-RAS model confirms that for both the 50- and 100-yr flood event, there is negligible change in WSEL and the bridge does not overtop. The minimum 2 ft of freeboard is satisfied in 50-year event. Figures 4-1 and 4-2 show the profile and cross section at the upstream face of the bridge. More details can be found in Appendix C.

Figure 4-1 Existing and Proposed Water Surface Profile (HEC-RAS)

Figure 4-2 Proposed Cross Section Upstream Face of the Bridge (HEC-RAS)

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4.2 Scour Countermeasures

Scour countermeasures were evaluated using the 200-yr flood event. FHWA’s Hydraulic Toolbox, Version 4.20.

Table 4-3 summarizes the results. and more detailed information and calculations can be found in Appendix C.

Table 4-3. Scour Calculations at Cross Section 128.9776

HEC 23 was used to determine riprap sizing and extents at Dry Wash Creek Trail Bridge. Using the 200-yr flood event velocity and depths, Class 4 riprap, D50 = 15”, is recommended. Per HEC 23 the riprap extents should be the greater of 25ft or twice the water depth; however, to minimize impacts to wetlands, the riprap extents have been reduced. Currently, there is not riprap at the existing bridge nor is there indication of scour. Appendix C contains more detailed information and calculations for scour and scour countermeasures.

4.3 Summary of Trail Drainage Improvements Methods

Field observations and discussions between the BOR, CFL, and AECOM recommended the trail following:

Culvert Cleaning: A total of 4 culverts have been quantified for cleaning.

Culvert Replacement or Additions: H&H has not been conducted. The sizing and placement of these proposed culverts was based on BOR recommendations and request. A total of 13 culverts have been quantified for replacement or new location.

1. 2- 12” CMPs are located along the Reservoir Trail at Station 106+90 and 131.95. This does not satisfy minimum criteria.

2. 8- 18” CMPs are located at Stations 1634+53, 1642+68, 857+90, 860+10, 897+75, 1512+86, and 1518+29. This does not satisfy minimum criteria.

3. 3-24” CMP are located at Stations 614+70, 847+74, and 850+89.

Ditches: Vegetated ditch grading/enhancements are recommended in 7 areas to convey runoff away from the trail. The flows will continue on historic paths.

Riprap Placement: There are a total of 17 areas that riprap is proposed. Depending on the culvert size, Class 2 or Class 3 riprap will be used.

Catch Basins: 2 FLH catch basins are proposed at Stations 1601+39 and 1624+05. H&H has not been conducted. The sizing and placement of these proposed culverts was based on BOR recommendations and request.

Concrete Curb & Gutter: Curb and Gutter is proposed in 7 areas. H&H has not been conducted. The sizing and placement of these proposed culverts was based on BOR recommendations and request.

1. 2 Areas proposed 6” curb depth

2. 5 Areas proposed 12” curb depth

Trail Overtopping: Currently there are 8 areas were runoff and sediment transport occurs over the trails.

In these areas, 3 options (culverts, low tailwater crossing, and a sediment basin) were considered for runoff conveyance and it was determined that a low tailwater crossing would be used. See Appendix D for more details.

New culverts will be CMP with metal end sections and riprap.

4.4 Erosion Control Measures

Erosion control measures will be used during and post construction activities in the form of silt fence, fiber rolls, check dams, riprap, seeding, and mulching. In environmentally sensitive areas, erosion control measures will be used to protect the areas against sediment transport.

Scour Type Depth (ft)

Comments

Degradation 0 HEC 18 Contraction NA Included in Abutment Scour

Spill through Abutment 1 NCHRP Method Pier 0 Not applicable Total 1

4-4

4.5 Summary

The existing shared use path spanning Dry Creek Wash will be relocated approximately 25 ft downstream of the existing bridge. The length and width will increase to 50 ft and 10 ft respectively. The 50-year, 100-year, and 500-year storm events do not overtop the bridge and the 50-year storm provides the required 2 ft of freeboard.

Class 4 (D50 = 15”) riprap is recommended for scour countermeasures.

The existing shared use path spanning the Arkansas River will be replaced with a bridge that has the low chord equal or greater than the existing low chord. It is assumed that the existing bridge adequately conveys flows as the channel is regulated by the dam. Although analysis has not been conducted, it is recommended to place Class 4 (D50 = 15”) riprap at the abutments for scour countermeasures.

Proposed trail drainage improvements included culvert replacements and cleaning at the discretion of the CO, 3 new vegetated ditches to ensure proper conveyance, and 3 areas of trail will be improved to ensure enhance drainage conveyance and minimize sediment transport across the trail.

This FINAL Hydraulics Report was prepared in accordance the FLH PDDM.

5-1

US Department of Transportation, Federal Highway Administration, Federal Lands Highway Project Development and Design Manual, January 2014.

AECOM, FLAP Scoping Report, December 2013.

AECOM, Hydrologic and Hydraulic Criteria Computation Methods Memorandum, April 2015.

NRCS Online Web Soil Survey, April 2015.

FEMA, FIRM: Pueblo County, Colorado, Map Number 0801470225B, September 1989.

AECOM, 30% CO FLAP 1099(1) Lake Pueblo Road & Trail Improvements Construction Plans, April 2014.

USACE, HEC-RAS, Version 4.1.0, January 2010.

USGS, Joseph P Capesius and Verlin C Stephens, Regional Regression Equations for Estimation of Natural Streamflow Statistics in Colorado: Scientific Investigations Report 2009-5136, Revised April 2014.

USGS, JE Vaill C Stephens, Analysis of the magnitude and Frequency of Floods in Colorado:Water-Resources Investigation Report 99-4190, 2000.

5 References

Appendix A: References A-1 H&H Criteria and Computation Methods Technical Memorandum

A-2 FEMA FIRM Panel

A-3 WRIR 99-4190 Regression Equation Documentation

A-4 NRCS Web Soil Survey

A-5 PDP Excerpt

Memorandum

Project: Lake Pueblo Road & Trail Improvements CO FLAP 1099(1) AECOM Project Number 60336366 Subject: Hydrologic and Hydraulic Criteria and Computational Methods Technical

Memorandum Date: April 13, 2015

1.0 Introductions

The purpose of this Hydrologic and Hydraulic Criteria and Computational Methods Technical Memorandum is to provide a summary of the applicable criteria that will be applied to the proposed improvements to Lake Pueblo Road and Trail Improvements.

2.0 Background and Description

The Federal Lands Access Program (FLAP) provides funding for public highways, roads, bridges, trails and transit systems that are located on, are adjacent to, or provide access to Federal Lands. The scope of work for this project is to perform environmental, engineering, hydraulic, pavement engineering design, and project management services toward delivery of a 100% PS&E for the Federal Highway Administration (FHWA), Central Federal Lands Highway Division (CFL) for proposed improvements to roads and trails in Lake Pueblo State Park.

This project includes reconstruction of approximately 4.2 miles of roads and 13.2 miles of trails in the Colorado Parks and Wildlife (CPW) Lake Pueblo State Park in Pueblo County, which is on the Bureau of Reclamations (BOR) Pueblo Reservoir Property. There are 3 segments of proposed improvements will be presented as schedules and options. In general, the proposed work by segment is as follows:

Segment 1 (Option): Roadway Improvements: Pulverize and widen existing pavement, shift roadway alignment in some areas, create a shared use path, ditch reconditioning, culvert cleaning, riprap replacement at culvert outlets, fencing repairs, and guardrail replacement.

Segment 2 (Schedule A): Shared use path trail system: Roadway pulverizing and repavement, profile modifications, ditch reconditioning, culvert cleaning, riprap replacement at culvert outlets, colored concrete, trail realignment, new pedestrian bridge, pedestrian bridge replacement, bridge/pedestrian rail replacement, guardrail/end terminal replacement, and new culvert locations.

Segment 3 (Option): Roadway Improvements: Widen, repave, add lanes for right turn movement, add median, realign roadway to accommodate fee station, ditch reconditioning, culvert cleaning, riprap replacement at culvert outlets, mill and overlay Union Pacific Railroad (UPRR) bridge and Dry Wash Creek bridge, clean deck drains, and replace guardrail and end treatments.

This project will include coordination with the CPW, Lake Pueblo State Park, BOR’s Pueblo Reservoir property.

Hydrologic and Hydraulic Criteria and Computational Methods Technical Memorandum Lake Pueblo Road and Trail Improvements

3.0 Criteria References

Hydrologic and hydraulic (H&H) analysis and design work associated with the proposed improvements will be in accordance with the methods, guidelines, and criteria set forth by the Federal Lands Highway Project Development and Design Manual (FLH PDDM).

Per CFL classification, the roads are designated as a High-Standard Road if any of the following criteria are satisfied:

Design Speed > 45 miles per hour (mph) Design Average Daily Traffic (ADT) > 1500 Designated as a “critical access road” Emergency evacuation routes, sole access to community/critical facilities (hospitals, power plants, water supply, wastewater treatment facilities).

Table 3.1: Roadway Classification

Criteria Segments 1, 2, and 3 Functional Classification Rural Major Collector Design Speed (miles per hour) 20 - 45 Projected ADT > 1500 Critical Access Road Designation No Roadway Classification High

4.0 Hydrology

To determine peak flows for the project, the following methods will be used:

1. Rational Method: To be used when contributing drainage areas are less than 200 acres.

2. Regression Equations: To be used when contributing drainage areas are greater than

200 acres.

3. Effective Federal Emergency Management Agency (FEMA) flows: Project area is located in a FEMA flood zone that provides peak flows.

Table 4.1 summarizes the storm frequencies to be used for this project.

Table 4.1: Storm Frequencies Drainage Classification Frequency

Roadway Classification High Cross Drainage: Culverts 50 yr Roadside Ditches Conveyance: 10 yr

Permanent Linings: 10 yr Temporary Linings: 2 yr

Pavement Drainage On-grade: 10 yr Sumps: 50 yr

Minimum Time of Concentration

6 min

Bridge Design: 50 yr Check: Greater of overtopping or 100 yr. Not to exceed 500 yr

5.0 Hydraulics

The hydraulics for culverts, ditches, pavement drainages, bridges, and scour analysis and countermeasures are summarized in Tables 5.1 through 5.5.

Table 5.1: Culvert Criteria

Item Criteria Headwater (HW) Elevation

Existing: Water surface elevation (WSEL) Shoulder Hinge Point New: WSEL Bottom of Aggregate Base Layer

Maximum HW to Depth (HW/D) Ratio

Diameter (D) 48 in, HW/D = 1.5 D > 48 in, HW/D = 1.2 Debris/Sediment Concern: A range of 0.8 to 1.0

Minimum Size Cross Culvert: 24 in All others: 18 in

Slope Preferred: 2% Minimum: 0.5% Minimum Not to exceed 10% for concrete and 25% for metal pipes

Cover Refer to FLH Standard Drawings: 602-1, 602-5, 602-7

Pipe Material Reinforced Concrete Pipe (RCP) Corrugated Metal Pipe (CMP) High Density Polyethylene (HDPE): Not preferred because of fire

Entrance and Outlet Treatments

Diameter 48 in, Flared End Section (FES) Diameter > 48 in, Headwalls and Wingwalls

Table 5.2: Ditches

Item Criteria Maximum Flows For Q > 50 cfs, Refer to PDDM River Hydraulics Section 7.4 Depth New Ditch: Depth < Bottom of the Aggregate Base Layer

Existing Ditch: Design < Shoulder Hinge Point

Slope Preferred: 1.0% Minimum: 0.5% for lined or paved ditches

Shear Stress Shear Stress < Permissible Shear Stress

Table 5.3: Pavement Drainage

Item Criteria Spread High: 3 ft of one travel lane

Less than 3 ft shoulder: ½ of the travel lane Depth On-grade: Depth < curb height or allowable spread depth

Sumps: Depth < 6 inches

Inlet Clogging Factor On Grade: No clogging, unless clogging is a known problem Sumps:

Grate inlets: 50% Curb Opening Inlets: None, unless clogging is a known problem

Rehabilitation Projects: No clogging, unless clogging

Minimums Pipe size: 15 in (design to flow full (no pressure flow) Pipe full velocity: 3 fps

Table 5.4: Bridges

Freeboard Minimum: 2 ft Wood Debris: 3.5 to 5 ft Ice Flows: 5 to 10 ft

Scour Abutments: Bridge Design Storm Event Foundation: 500 yr Roadway Overtopping: minimum 100 yr

Table 5.5: Scour Countermeasures Analysis: Using HEC-RAS, Hydraulic Toolbox

General Scour: Aggradation and Degradation

HEC-RAS or Hydraulic Toolbox 4.2

Lateral Channel Movement Not considered:

Contraction Scour Clear-Water or Live-bed Local Scour: Pier HEC 18 Local Scour: Abutment NCHRP Project 24-20 Method: Use Hydraulic Toolbox 4.2

6.0 Erosion Control Measures

Erosion control measures will be used during and post construction activities in the form of silt fence, sediment control fiber rolls, check dams, riprap, riprap rundowns, seeding, and mulching.

Energy dissipation will adhere to HEC-14.

7.0 Summary

The information contained in this memorandum is only a summary of the applicable criteria. All criteria will be reviewed and adhere to by the project engineer. Any changes to the design/planning criteria will be noted in future memorandums.

8.0 References

USDOT, FHWA, Federal Lands Highway Project Development and Design Manual, January 2014.

USGS, Water Resources Investigations Report 99-4190: Analysis of the Magnitude and Frequency of Floods in Colorado, 2000.

FHWA, Hydraulic Toolbox 4.2, August 2014.

FEMA, FIRM Pueblo County, Colorado (Unincorporated Areas), 080147 0225B, September 1989.

USDOT, Hydraulic Engineering Circular No. 18: Evaluating Scour at Bridges, Fifth Edition, April 2012.

kirkbridet Callout Pedestrian Bridge Replacement

Fi gu re 1.

B ou nd ar ie s of hy dr ol og ic re gi on s an d lo ca tio n of st re am flo w ga gi ng st at io ns in C ol or ad o an d ad ja ce nt

S ta te s.

IN

TR

O D

UC

TI

O N

(3 8.

4.

ESTIMATING MAGNITUDE OF PEAK DISCHARGES 9

Table 1. Regional flood-frequency equations, Colorado

[Q, discharge, in cubic feet per second; A, drainage area, in square miles; P, mean annual precipitation, in inches; S, mean drainage-basin slope, in foot per foot]

Recurrence interval, in years Regression equation

Standard error of the model, in percent

Average standard error of prediction, in percent Mountain region

2 Q = 11.0 (A) 0.663 (S + 1.0) 3.465 58 52 5 Q = 17.9 (A) 0.677 (S + 1.0) 2.739 48 47

10 Q = 23.0 (A) 0.685 (S + 1.0) 2.364 44 45 25 Q = 29.4 (A) 0.695 (S + 1.0) 2.004 41 44 50 Q = 34.5 (A) 0.700 (S + 1.0) 1.768 41 44

100 Q = 39.5 (A) 0.706 (S + 1.0) 1.577 42 44 200 Q = 44.6 (A) 0.710 (S + 1.0) 1.408 44 45 500 Q = 51.5 (A) 0.715 (S + 1.0) 1.209 48 47

Rio Grande region 2 Q = 0.03 (A) 0.979 (P) 1.615 78 61 5 Q = 0.12 (A) 0.940 (P) 1.384 64 55

10 Q = 0.25 (A) 0.914 (P) 1.277 58 53 25 Q = 0.52 (A) 0.884 (P) 1.117 53 51 50 Q = 0.81 (A) 0.864 (P) 1.121 51 50

100 Q = 1.19 (A) 0.846 (P) 1.074 50 49 200 Q = 1.67 (A) 0.828 (P) 1.036 49 49 500 Q = 2.48 (A) 0.808 (P) 0.995 50 49

Southwest region 2 Q = 28.7 (A) 0.699 85 62 5 Q = 50.5 (A) 0.693 74 58

10 Q = 66.0 (A) 0.697 71 57 25 Q = 86.3 (A) 0.704 71 57 50 Q = 102.0 (A) 0.709 73 58

100 Q = 118.4 (A) 0.715 76 59 200 Q = 135.5 (A) 0.720 79 60 500 Q = 159.4 (A) 0.728 85 62

Northwest region 2 Q = 0.39 (A) 0.684 (P) 1.304 83 62 5 Q = 2.84 (A) 0.674 (P) 0.833 71 58

10 Q = 7.56 (A) 0.671 (P) 0.601 68 56 25 Q = 20.6 (A) 0.669 (P) 0.362 67 56 50 Q = 38.8 (A) 0.667 (P) 0.210 67 56

100 Q = 104.7 (A) 0.624 75 59 200 Q = 118.5 (A) 0.624 78 60 500 Q = 137.6 (A) 0.623 83 61

Plains region 2 Q = 39.0 (A) 0.486 233 93 5 Q = 195.8 (A) 0.399 204 89

10 Q = 364.6 (A) 0.400 212 90 25 Q = 725.3 (A) 0.395 232 92 50 Q = 1116 (A) 0.392 250 95

100 Q = 1640 (A) 0.388 267 96 200 Q = 2324 (A) 0.385 285 98 500 Q = 3534 (A) 0.380 306 100

Plains region

0.4862 Q = 39.0 (Q = 39.0 (A = 39.0 ( = 39.0 ( ) 233 93233 93

0.3995 Q = 195.8 (Q = 195.8 (A = 195.8 ( = 195.8 ( ) 204 89204 89

0.40010 Q = 364.6 (Q = 364.6 (A = 364.6 ( = 364.6 ( ) 0.400 212 90212 90

0.39525 Q = 725.3 (Q = 725.3 (A = 725.3 ( = 725.3 ( ) 232 92232 92

0.39250 Q = 1116 (Q = 1116 (A = 1116 ( = 1116 ( ) 0.392 250 95250 95

0.388100 Q = 1640 (Q = 1640 (A = 1640 ( = 1640 ( ) 0.388 267 96267 96

0.385200 Q = 2324 (Q = 2324 (A = 2324 ( = 2324 ( ) 0.385 285 98285 98

0.380500 Q = 3534 (Q = 3534 (A = 3534 ( = 3534 ( ) 0.380 306 100306 100

Federal Highway Administration Central Federal Lands Highway Division

Federal Lands Access Program Scoping Report

Colorado Parks and Wildlife/Bureau of Reclamation

Pueblo County

Colorado

CO FLAP 1099 (1)

Lake Pueblo Road & Trail Improvements

Prepared By:

AECOM

717 17th Street, Suite 2600

Denver, CO 80202

CO FLAP 1099(1)

The trail pavement section issues stem from mostly poor drainage, maintenance vehicle loads, and isolated cases of subgrade failure. Since the trail system pavement was placed over 30 years ago it is also a victim of oxidation and is past its service life.

3. Explain areas of special concern for pavement design; bus parking, bus stops, trail crossings, etc.

There are no bus stops or bus parking locations along the route. There are at least three trail crossings across the proposed roadway improvement areas. The project should consider pouring the roadway crossings in a two-toned color concrete scheme in combination with advance signing to alert approaching drivers of their locations.

4. Provide the existing average pavement and shoulder widths. Provide information on how much grade raise is possible and whether a grade raise is allowable.

Existing pavement width for majority of the roadway is 23 feet with earthen shoulders varying from 0.5 feet to 7 feet. The grade raise will be limited to the depth of overlay (assumed to be 4-5”).

5. Provide any available information on existing asphalt and base depths.

Existing pavement thickness was field measured between 2.5 inches and 3 inches.

6. Provide information on the traffic volume and the amount of heavier traffic such as delivery trucks, buses, RV’s and tractor trailer rigs. Provide the existing speed limit.

No official truck counts are available. It was observed during the field visit that Juniper Road was used by a heavy two-axle delivery truck (Fedex) and a tractor trailer (size unknown) was observed coming onto the site to drop off fencing materials for the Juniper Pump Station. The tractor trailer came in on Reservoir Road (from Hwy 96) and proceeded to Spillway Drive to drop off the load. This will probably be the delivery route for the duration of the Juniper Pump Station project.

7. Provide a listing of local sources for aggregate, riprap, asphalt and concrete production. Include the distance of each source to the project.

Asphalt, concrete and aggregate can be competitively obtained from providers located in the city of Pueblo (less than 10 miles from the project site). Embankment material may be stockpiled from the Juniper Pump Station near the CPW maintenance facility (Juniper Rd./Reservoir Rd.).

J. HYDROLOGY / HYDRAULICS

Address the following items for all major drainage structures (i.e. bridge and culvert structures having a vertical opening greater than 48 inches; open-bottom structures; fish passage/AOP structures):

1. Are there any state or local design standards and/or criteria for design floods, roadway overtopping, backwater, freeboard, or analytical methods at waterway crossings that will supersede the PDDM?

No.

2. Describe type, size, location, and condition of existing major drainage structures to be retained. Photograph structure inlet/outlet and stream channel looking from structure upstream and downstream.

Juniper Rd., Bessemer Ditch Outlet:

Bessemer Ditch outlet from Dam (looking at downstream outlet structure)

Juniper Rd., Bridge over Arkansas River/Spillway: 36 ft x 202 ft, Double span

Under south end of bridge (looking at north side bank)

South end of bridge (looking at riprap bank)

Bridge over Dry Wash Creek: 36 ft x98 ft, Single span

Standing water under bridge (looking at south girder line)

Downstream channel opening (looking at south girder line)

Trail Bridge over Arkansas River: 7.3 ft (out to out) x 120 ft, Pre-fabricated, Single span

South approach to Trail bridge (looking at vegetated banks)

3. Describe existing scour/erosion at structure inlets/outlets, deposition of sediment or debris at inlets/outlets, abrasion or corrosion of structure material, presence of riprap aprons at inlets/outlets, and any associated roadway embankment stability concerns. Photograph cited problems.

For the majority of the project most pipes were clean or relatively clean. There are some instances of damaged pipe and pipe needing cleaned out. Most culverts lacked outlet protection.

Culvert with mystery pvc pipe and no outlet protection (S. Marina Rd. looking at outlet)

Partially plugged invert under Juniper Rd. (north of S. Marina Rd. intersection)

Sediment from upstream erosion washing across trail (north of Rock Canyon Rd.)

Trail junction, double-45” HE culverts with debris at inlet (southwest of Swim Beach.)

Juniper Rd., 42” rusting culvert pipe with plugged outlet (400 west of Sailboard Rd. looking at outlet)

Juniper Rd., 96” culvert with light sediment (east of CG Trail crossing looking at invert)

Juniper Rd., 42” culvert, scour hole from no outlet protection (west of CG Trail crossing looking at outlet)

4. Photograph and describe the character of channel bed and bank material (e.g. rock, rock-like; cohesive sand, silt, clay; non-cohesive sand, gravel, cobble, boulder; mix) in all channels that may be crossed by open-bottom structures (bridges, arch culverts, etc.). Note below if sampling and testing of channel bed material will be required to accurately define character.

Characteristics of the existing channel material were not evaluated. Channel bed sampling and testing may be required in the area downstream of the bridge over Dry Wash Creek if an alternate trail alignment is needed to cross the wash.

No other work is expected to impact the banks.

5. Describe any channel migration concerns that may impact the roadway now or in the future (photograph problem area looking up and downstream).

No channel migration problems were identified during the scoping visit.

6. Is the project within a floodplain regulated by FEMA? If yes, provide the name of the local floodplain administrator.

No.

7. Is the project located within 100 miles of the West coastline (National Oceanic and Atmospheric Administration (NOAA) fisheries jurisdiction)?

No.

8. For existing bridges over waterways with a total span of 20’ or greater, has the bridge been evaluated for scour susceptibility? If yes, obtain Bridge Scour Evaluation Report.

No bridge scour reports have been done.

9. For non-major drainage structures or features, such as culverts, roadside ditches, pavement inlets, etc. locate, describe and photograph any known or identified condition or performance problems.

For minor drainage structures there were isolated cases of riprap protection missing at outlets.

Some culverts had end of pipes and sections that were crushed and need replaced.

Culvert end crushed under Fee Station slip ramp (looking north)

Juniper Rd., 42”culvert with busted pipe joint 12 ft in, rusting culvert pipe with near outlet,(400 west of Sailboard Rd. looking inlet)

S. Marina Rd., approximately 1,000 lin. ft of poorly graded ditch, (looking southeast along south ditch line)

Juniper Rd., approximately 800 lin. ft of poorly graded ditch, (looking west along south ditch line)

K. BRIDGE

1. Provide existing structure data (bridges, retaining walls, tunnels).

a) Collect structure as-builts, contract plans, inspection reports, structure ratings, NBIS reports

Bike Path at the Bessemer Ditch (Juniper Road MP 5.55): Movement of a guard rail and bike path was observed where the bike path and 10). The 7-foot wide section of bike path is located at the crest of a 35 degree slope. At the toe of the slope is a concrete culvert leading into the reservoir starts the Bessemer Ditch. At the crest of the slope, small timbers ties (1 to 2 feet high) retain soil and support the adjacent guard rail and a concrete curb. Erosion of the soil retained by the ties was observed in areas and both the timber ties, guard rail, and concrete curb have started to overturn. Longitudinal cracks have developed within the bike path (possibly scarps). We understand that shallow buried utilities are buried under the bike path or in the adjacent roadway.

c) Surface water and groundwater problem areas.

None.

2. Provide the location of anticipated structures types (bridge, retaining wall or other earth retaining structures, box culvert of other drainage features) along the proposed route, including anticipated foundation requirements. List any potential constructability issues or impacts to the project associated with construction of the structures. List potential, feasible alternatives to anticipated structures, including EDC initiatives.

Potential for new trail bridge at existing trail bridge location. The intent is to preserve the existing abutments and retrofit if necessary. The existing material around the foundations will be hand analyzed to determine allowable bearing capacity.

I. PAVEMENTS

1. Provide recommendation on the anticipated structural section. Consider the reuse of the existing pavement in the new structural section.

The project will involve pulverizing and compacting the existing pavement section and then placing an estimated 5” overlay atop the pulverized material. Pavement section should be confirmed by a materials engineer and based on projected traffic growth and service life of 20 years.

For the trail system, the existing asphalt pavement will be pulverized and compacted before placing an estimated 6” of concrete. New sections of trail will also use 6” of trail on 4” of compacted aggregate base.

J. HYDROLOGY/HYDRAULICS

1. Are any stream and/or floodplain restoration efforts anticipated? If so, describe.

None planned.

2. Are any low-water crossings anticipated? If so, describe.

Potential for several existing low-water trail crossing to remain low water crossings. In most instances the trail will be raised to convey water under the trail via pipe(s).

3. Are any fish passage needs anticipated? If so, describe issues and locations.

None anticipated.

4. Is there a potential for embankment and/or retaining walls being located in and parallel to streams/channels or floodplains? If yes, describe.

At the bridge over Dry Wash Creek the trail narrows to 3 foot wide to cross the bridge over the creek. This is a potential area for realignment of the trail to alleviate the pinch point (across the bridge) and provide safe passage across the creek. Depending on the type of crossing used some fill may encroach the creek.

5. Describe any anticipated channel stabilization work needed to protect the proposed roadway.

No channel stabilization is planned for the project. There are some sections of trail that meander close to the Arkansas River and would involve riprap armament along the edges of concrete.

K. BRIDGE

1. Discuss proposed structural improvements

a) Determine/propose structure design criteria - AASHTO LRFD Bridge Design Specifications with exceptions (list) per local/state/owner.

No roadway bridges are affected. The trail bridge is slated for potential replacement (if funding warrants). Design criteria to be supplemented after cost estimates developed.

b) Structure type(s), layout, and alignment, including retaining walls and extent of falsework clearances.

None required.

c) Proposed foundation options.

Existing bridges to remain in place on existing foundations. Trail bridge foundations would require analysis to determine if they can remain.

d) Number of lanes, sidewalk, deck drains, and utility requirements. Include ADA needs as applicable.

Existing bridges have two lanes, a 3 foot sidewalk, deck drains and carry utilities. 3 foot sidewalks/pathways are not ADA compliant.

e) Detour needs/alignment location.

None required.

f) Bridge railing and transition railing type and crash test level provided.

Proposed guardrail to bridge rail transition railings should meet Test Level (TL-2) or (TL-3) depending on design speeds.

g) Design live loading and permit loads, as required.

Location Structure No. Design Live Load Permit Load Bridge over Arkansas R. ECA P 001 HS 20 None

Appendix B: Hydrology B-1 Hydrologic Summary

B-2 StreamStats

B-3 NSS Results

Drainage Area (A)= 9.06 square miles Region = Plains Region

Recurrence Interval (Years)

WRI 99-4190

Equation

Q (cfs)

Average Standard Error of Prediction

Q (cfs)

Average Standard Error of Prediction

2 Q = 39 (A) 0.486 114 93 88.7 180 5 Q = 195.8 (A) 0.399 472 89 238 140

10 Q = 364.6 (A) 0.400 880 90 382 140 25 Q = 725.3 (A) 0.395 1732 92 659 140 50 Q = 1116 (A) 0.392 2648 95 908 140

100 Q = 1640 (A) 0.388 3857 96 1260 140 200 Q = 2324 (A) 0.385 5429 98 2410 160 500 Q = 3534 (A) 0.380 8165 100 2350 140

2 NSS = National Streamflow Statistics Program, Version 6.1. See next page for equations

Assumptions:

Hydrology for Pedestrian Bridge Relocation Dry Wash Creek at Lake Pueblo

Regression Equations1

1. StreamStats Basin Area: Is accurate and will be used for all calculations.

2. Watershed Area > 200 acres; therefore rational method is not to be used.

3. Regression Equations: Use these rounded peak flows as the predection error is less and the flows are more conservative.

4. Dry Wash Creek is within a FEMA ZONE A designation.

1 USGS: Analysis of Magnitude and Frequency of Floods in Colorado: Water Resources Investigations Report 99-4190.

2015.04.09: Preliminary Calculations

Streamstats & NSS2

StreamStats Print Page

Ped Bridge Relocate

3/19/2015 1:29:00 PM

Page 1 of 1USGS StreamStats

3/19/2015http://streamstatsags.cr.usgs.gov/co_ss/default.aspx?stabbr=co&dt=1426792538793

Basin Characteristics Report

Date: Thu Mar 19 2015 13:35:26 Mountain Daylight Time NAD27 Latitude: 38.2874 (38 17 15) NAD27 Longitude: -104.7685 (-104 46 07) NAD83 Latitude: 38.2874 (38 17 15) NAD83 Longitude: -104.7691 (-104 46 09)

Parameter Value

6-hour, 100-year precipitation, in inches 3.49

Mean basin slope computed from 10 m DEM, in percent 2.94

Area that drains to a point on a stream in square miles 9.06

Mean Basin Elevation in feet 5070

Mean annual precipitation, in inches 13.38

Percentage of basin above 7500 ft elevation 0

Page 1 of 1Basin Characteristics Report

3/19/2015http://streamstatsags.cr.usgs.gov/gisimg/Reports/BasinCharsReport189517_2015319133526.htm

Get Latitude Longitude To make a search, use the name of a place, city, state, or address, or click the location on the map to get lat long coordinates.

Place Name

Type a place name Find

Add the country code for better results. Ex: London, UK

Latitude

38.287417

Longitude

-104.768876

Lat Long

(38.287417, -104.768876)

GPS Coordinates

38° 17' 14.7012'' N 104° 46' 7.9536'' W

Map Mouse Over Location

(38.290062, -104.766752) Share this location link

<a href="http://www.latlong.net/c/?lat=38.287417&long=-104.768876" target="_blank">(38.287417, -104.768876)</a>

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Map data ©2015 Google Imagery ©2015 , DigitalGlobe, U.S. Geological Survey, USDA Farm Service AgencyReport a map error100 m

Page 1 of 9Latitude Longitude Finder on Map Get Coordinates

3/19/2015http://www.latlong.net/

Streamstats Ungaged Site Report

Date: Thu Mar 19 2015 13:32:03 Mountain Daylight Time Site Location: Colorado NAD27 Latitude: 38.2874 (38 17 15) NAD27 Longitude: -104.7685 (-104 46 07) NAD83 Latitude: 38.2874 (38 17 15) NAD83 Longitude: -104.7691 (-104 46 09) Drainage Area: 9.06 mi2

Peak-Flows Basin Characteristics 100% Plains Region Peak Flow (9.06 mi2)

Parameter Value Regression Equation Valid Range

Min Max

Drainage Area (square miles) 9.06 0.5 2930

6 Hour 100 Year Precipitation (inches) 3.49 2.4 5.1

Low-Flows Basin Characteristics 100% Undefined Region (9.06 mi2)

The selected watershed is entirely in an area for which flow equations were not defined.

Flow-Duration Basin Characteristics 100% Undefined Region (9.06 mi2)

The selected watershed is entirely in an area for which flow equations were not defined.

Maximum-Flows Basin Characteristics 100% Undefined Region (9.06 mi2)

The selected watershed is entirely in an area for which flow equations were not defined.

Mean-Flows Basin Characteristics 100% Undefined Region (9.06 mi2)

The selected watershed is entirely in an area for which flow equations were not defined.

Peak-Flows Streamflow Statistics

Statistic Flow (ft3/s) Prediction Error (percent) Equivalent years of record

90-Percent Prediction Interval

Minimum Maximum

PK2 88.7 180

PK5 238 140

PK10 382 140

PK25 659 140

PK50 908 140

PK100 1260 140

PK200 2410 160

PK500 2350 140

Page 1 of 1Streamflow Statistics Report

3/19/2015http://streamstatsags.cr.usgs.gov/gisimg/Reports/FlowStatsReport189517_201531913323.htm?cm...

PedBridgeDryWashCreekHydrology.txt National Streamflow Statistics…