EAST PLATTE AVENUE BRIDGE REPLACEMENT OVER SAND CREEK · respec.com final channel design report east platte avenue bridge replacement over sand creek contract t008594 prepared for

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FINAL CHANNEL DESIGN REPORT

EAST PLATTE AVENUE BRIDGE REPLACEMENT OVER SAND CREEK CONTRACT T008594

PREPARED FOR HDR Engineering, Inc. 2060 Briargate Parkway Suite 120 Colorado Springs CO 80920

City of Colorado Springs 30 S. Nevada Avenue Suite 403 Colorado Springs, CO 80903

Pikes Peak Rural Transportation Authority 15 S. 7th Street Colorado Springs, CO 80905

PREPARED BY

RESPEC 720 South Colorado Boulevard Suite 410 S Denver, Colorado 80246 Project Engineer: Carrie Herbolsheimer, PE, CFM

JANUARY 2019

RESPEC Project Number 03177

FINAL Channel Design Report rSI Project No. 3042

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TABLE OF CONTENTS

CAPITAL PROJECT DRAINAGE REPORT SIGNATURE PAGE .................................................................................................. 1 ENGINEER’S STATEMENT ................................................................................................................................................................................1 CITY PROJECT MANAGER’S STATEMENT ....................................................................................................................................................1 CITY OF COLORADO SPRINGS STATEMENT: ..............................................................................................................................................1

I. INTRODUCTION/PURPOSE ............................................................................................................................................. 2 A. PROJECT ..................................................................................................................................................................................................2 B. REPORT PURPOSE .................................................................................................................................................................................2 C. PROJECT LOCATION ............................................................................................................................................................................2

II. PREVIOUS REPORTS AND JURISDICTIONAL REQUIREMENTS ..................................................................................... 4 A. DRAINAGE BASIN PLANNING STUDY ...............................................................................................................................................4 B. FEDERAL EMERGENCY MANAGEMENT AGENCY ..........................................................................................................................4 C. US FISH AND WILDLIFE SERVICE ......................................................................................................................................................4 D. US ARMY CORPS OF ENGINEERS ......................................................................................................................................................4

III. SITE DESCRIPTION .......................................................................................................................................................... 5 A. CHANNEL DESCRIPTION AND FEATURES ......................................................................................................................................5 B. TRIBUTARY WATERSHED ....................................................................................................................................................................5 C. ADJACENT DEVELOPMENTS ..............................................................................................................................................................6 D. MAJOR CROSSINGS .............................................................................................................................................................................6 E. PARCEL OWNERSHIP............................................................................................................................................................................6 F. SOILS CONDITIONS ..............................................................................................................................................................................6

IV. PROPOSED CONDITIONS ................................................................................................................................................ 6 A. PROPOSED CONDITIONS MAP ..........................................................................................................................................................6 B. CHANNEL AND ADJACENT LAND USE ............................................................................................................................................7 C. PROPOSED CHANNEL IMPROVEMENTS – NEED ..........................................................................................................................7 D. PROPOSED CHANNEL IMPROVEMENTS – DESCRIPTION ..........................................................................................................7 E. COMPLIANCE WITH OTHER STUDIES ..............................................................................................................................................7 F. PUBLIC MAINTENANCE NEEDS .........................................................................................................................................................7

V. CHANNEL, STRUCTURE, AND UTILITY CROSSING DESIGN .......................................................................................... 8 A. COMPLIANCE WITH OTHER STUDIES ..............................................................................................................................................8 B. HYDRAULIC CRITRIA .............................................................................................................................................................................8 C. SITE CONSTRAINTS ..............................................................................................................................................................................8 D. MAJOR CHANNEL COMPONENTS AND ATRIBUTES ....................................................................................................................8 E. MAJOR DROP STRUCTURE COMPONENTS AND ATTRIBUTES .................................................................................................8 F. MAJOR COMPONENTS AND ATRIBUTES ........................................................................................................................................8 G. MAJOR DRAINAGE STRUCTURE COMPONENTS AND ATRIBUTES ..........................................................................................8 H. HYDRAULIC ANALYSIS – ASSUMPTIONS AND RESULTS ............................................................................................................9


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a. Manning’s n-Values ................................................................................................................................................................9 b. Contraction and Expansion Coefficients ..........................................................................................................................9 c. Bridge Modeling ......................................................................................................................................................................9 d. Boundary Conditions .............................................................................................................................................................9 e. Hydraulic Modeling – Proposed and Existing Conditions ............................................................................................10

I. RIPRAP DESIGN ......................................................................................................................................................................................11 J. STABILITY ANALYSIS.............................................................................................................................................................................11 K. IMPROVEMENT DESIGN .......................................................................................................................................................................11

VI. PHASING .......................................................................................................................................................................... 11 A. GENERAL TIMELINE ..............................................................................................................................................................................11 B. MAJOR FACILITY TIMING CONSTRAINTS .......................................................................................................................................12 C. ORDER OF CONSTRUCTION ...............................................................................................................................................................12

VII. SUMMARY ........................................................................................................................................................................ 12

VIII. REFERENCES .................................................................................................................................................................... 13

APPENDIX A - HEC-RAS HYDRAULIC RESULTS ...................................................................................................................... 1

APPENDIX B - CALCULATIONS ................................................................................................................................................ 2

APPENDIX C - WORK MAPS FOR EXISTING AND PROPOSED CONDITIONS ......................................................................... 3


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LIST OF TABLES

Table Page

Table 1. Summary of project design flow rates 6

Table 2. Summary of Manning's n-values in model 9

Table 3. Comparison of Water Surface Elevations – 100-year flows 10

LIST OF FIGURES

FIGURE Page

Figure 1. Vicinity Map. 3

Figure 2. Location Map. 3

Figure 3. Project Tributary Watershed 5


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CAPITAL PROJECT DRAINAGE REPORT SIGNATURE PAGE

ENGINEER’S STATEMENT This report and plan for the drainage design of East Platte Avenue Bridge Replacement Over Sand Creek was prepared by me (or under my direct supervision) and is correct to the best of my knowledge and belief. Said report and plan has been prepared in accordance with the City of Colorado Springs Drainage Criteria Manual and is in conformity with the master plan for the drainage basin. I understand that the City of Colorado Springs does not and will not assume liability for drainage facilities designed by others. I accept responsibility for any liability caused by any negligent acts, errors, or omissions on my part in preparing this report.

Signature (Affix Seal) Date

Colorado P.E. No.

CITY PROJECT MANAGER’S STATEMENT I hereby certify that the drainage for East Platte Avenue Bridge Replacement Over Sand Creek shall be constructed according to the design presented in this report. I further understand that field changes must be reviewed by the City Review Engineer to ensure conformance with the original design intent. I am employed by and perform engineering services solely for the City of Colorado Springs, and therefore am exempt from Colorado Revised Statute Title 12, Article 25, Part 1 according to §12-25-103(1) C.R.S.

Name of City Project Manager

Authorized Signature Date

CITY OF COLORADO SPRINGS STATEMENT: Filed in accordance with Section 7.7.906 of the Code of the City of Colorado Springs, 2001, as amended.

For City Engineer Date

Conditions:

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I. INTRODUCTION/PURPOSE

A. PROJECT The East Platte Avenue Bridge Replacement Over Sand Creek project is a City of Colorado Springs (City) and Colorado Department of Transportation (CDOT) funded project. The project will replace and widen the ageing East Platte Avenue bridge crossing while maintaining the 100-year water surface elevations at or below the regulatory Federal Emergency Management Agency (FEMA) Base Flood Elevations (BFEs).

B. REPORT PURPOSE This Final Channel Design Report describes the design criteria and analysis of proposed channel design features for the replacement of the East Platte Avenue bridge over Sand Creek. This report is part of a larger project design submittal and is intended to be considered as a part of the whole submittal. The design and resulting plans and specifications related to channel design have been completed by RESPEC as part of the HDR design team for the City of Colorado Springs.

C. PROJECT LOCATION The project site is generally the intersection of East Platte Avenue and Sand Creek, approximately 0.4 miles west of the intersection of East Platte Avenue and Powers Boulevard in the City of Colorado Springs in El Paso County, Colorado. Streets intersecting East Platte Avenue near the project site include Space Center Drive to the east of Sand Creek and Babcock Road to the west of Sand Creek. The site lies within the SE and SW ¼ of Section 12 and the NE and NW ¼ of Section 13 Township-14-South Range-66-West of the Sixth Principal Meridian in El Paso County, Colorado. Sand Creek flows from the northeast to the southwest through the site. The project site is not located in a platted subdivision, nor are any of the immediately adjacent properties part of any platted subdivision. Adjacent properties are owned by Patriot Park Investments, LLC (to the northeast of the project site), Eaglecleft, LLC (to the northwest), and Dynamic Sciences, Inc. (to the southeast and southwest). All adjacent land is either undeveloped or commercial in nature. The project site is shown on the Vicinity and Location Maps below (Figure 1 and Figure 2).


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Figure 1. Vicinity Map.

Figure 2. Location Map.


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II. PREVIOUS REPORTS AND JURISDICTIONAL REQUIREMENTS

A. DRAINAGE BASIN PLANNING STUDY The Drainage Basin Planning Study (DBPS) for the project site was developed in 1996 by Kiowa Engineering. A Master Plan for Sand Creek between Hancock Expressway and East Platte Avenue was prepared by Ayres Associates, with a final draft submitted in 2013. This project design is consistent with the recommendations from the 2013 Master Plan.

B. FEDERAL EMERGENCY MANAGEMENT AGENCY The Federal Emergency Management Agency (FEMA) Flood Insurance Study (FIS) for the area was published in 1999. The Flood Insurance Rate Map (FIRM) for the project reach is map number 08041C0753F, with an effective date of March 17, 1997. There are no Letters of Map Revision (LOMR) affecting the project site. Based on the FIRM, this site is located within a 100-year floodplain with floodway (Zone AE). The goal of this project is to permit the proposed East Platte Avenue Bridge over Sand Creek using a zero-rise conditions permit through Pikes Peak Regional Building Department (PPRBD). The requirements for obtaining this permit (within the floodway) are to show that the installation of the proposed improvements will not cause a rise in the 100-year floodplain elevation within or adjacent to the project limits relative to the effective (regulatory, published elevations), or the corrective effective (updated based upon existing conditions)100-year water surface elevations. The reach of Sand Creek from West Fork Sand Creek to Galley Road has changed significantly since the Flood Insurance Study was published for the creek. These changes include degradation of the channel, up to 30-feet in drop in some locations, as well as the installation of several grade control structures or other improvements. Upon completion of the bridge installation a Letter of Map Revision (LOMR) will be submitted to FEMA for the reach. Based upon direction from PPRBD, the LOMR will be submitted in order to update the regulatory model based upon better mapping and information. The corrected effective model for the LOMR will be based upon as-constructed conditions for the bridge and other projects within the LOMR reach. This model will utilize approved LOMRs at the upstream and downstream limits of the reach as boundary conditions and will utilize these models as tie-in points for Flood Insurance Rate Map (FIRM) Zone AE and floodway limits as well as the profiles in the Flood Insurance Study (FIS).

C. US FISH AND WILDLIFE SERVICE The US Fish and Wildlife Service (USFWS) will be contacted.

D. US ARMY CORPS OF ENGINEERS A Section 404 Nationwide Permit application will be submitted to the USACE.


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III. SITE DESCRIPTION

A. CHANNEL DESCRIPTION AND FEATURES The delineation of Waters of the US (WUS) completed for this project identified multiple species of native grasses and forbs as well as trees, shrubs, and vines including plains cottonwood, Russian olive, Siberian elm, western snowberry, and Virginia creeper. Sandbar willow and narrow leaf cattail were also identified. The delineation report provides extensive additional information regarding the ground cover found in the project site. The channel and surrounding lands are undeveloped. Sand Creek downstream of this project has degraded up to 30 feet to shale bedrock over the last decade. A downstream project, currently under construction will return Sand Creek to a stable channel slope of 0.4% downstream of the bridge.

B. TRIBUTARY WATERSHED

Figure 3. Project Tributary Watershed

The hydrology for the tributary watershed was not studied as a part of this project, but is discussed in greater detail in the preliminary drainage report included as a part of the overall project 30% design submittal. The FEMA regulatory flow rate obtained from the 1999 Flood Insurance Study (FIS) was used for the design. The 1-, 1.5, 2-, 10-, 50-, and 500-year flow rates were also referenced in the project design, however all improvements have been designed for the 100-year peak flow conditions. Table 1, below, summarizes the flow rates utilized for the design project.


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Table 1. Summary of project design flow rates

Return Period Flow Rate (cfs) Source

1-yr 870 2013 Master Plan

1.5-yr 1,280 2013 Master Plan

2-yr 1,430 2013 Master Plan

10-yr 1,890 FEMA FIS



200-yr 7054 Log-normal interpolation


C. ADJACENT DEVELOPMENTS The project site is bordered by industrial and undeveloped properties.

D. MAJOR CROSSINGS The East Platte Avenue bridges being replaced cross the Sand Creek channel within the project reach. Utilities crossing the channel within the project improvements include overhead electric, gas, and communications lines. Water and sanitary sewer utilities are also located within the project site. The project improvements have been designed to avoid existing utility crossings. The design has been coordinated with the appropriate utility owners.

E. PARCEL OWNERSHIP The project is located primarily within City-owned right-of-way. Property acquisition has been addressed as needed.

F. SOILS CONDITIONS A geotechnical investigation has been incorporated into the project design.

IV. PROPOSED CONDITIONS

A. PROPOSED CONDITIONS MAP A copy of the final design drawings has been included with the overall project submittal.


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B. CHANNEL AND ADJACENT LAND USE The channel alignment and adjacent land use will remain unchanged as a result of this project. Sand Creek is a flood control channel with future fat tire bike access within the channel. Channel access is provided by a maintenance access road along the eastern edge of the channel, accessible from Bijou Street. Current adjacent land uses include business and industrial developments to the north of the project site, a Flea Market to the southwest, and undeveloped land to the southeast of the project site.

C. PROPOSED CHANNEL IMPROVEMENTS – NEED The East Platte Avenue bridges require replacement. Channel improvements will be made to maintain stable channel conditions between the upstream and downstream grade control structures, to protect the proposed bridge and trail system, and to maintain a zero-rise condition for the floodplain in relation to the regulatory BFEs.

D. PROPOSED CHANNEL IMPROVEMENTS – DESCRIPTION Proposed channel improvements include the installation a new bridge for the East Platte Avenue crossing of Sand Creek. Alternatives considered for the 30% design included various bridge opening widths and pier configurations. The selected alternative consists of a 190-ft bridge opening with three spans. Freeboard of 2.71’ is maintained between the water surface elevation 50 feet upstream of Platte Avenue and the low chord of the bridge. Channel grading and installation of riprap pier and abutment protection are included. Additionally, a recreational trail stub will be installed underneath the bridge for connection with a future Parks department project. The trail protection will consist of sloped grouted boulders between the channel bottom and the trail edge. Scour calculations were performed using criteria from the Federal Highway Administration (FHWA) Hydraulic Engineering Circular No. 18 (HEC-18). The calculations are provided, and assumptions are discussed in further detail in Appendix B.

E. COMPLIANCE WITH OTHER STUDIES The project design is in conformance with the 2013 Master Plan. The 2013 Master Plan recommends an equilibrium slope of 0.4% for the reach of Sand Creek between Airport Road and East Platte Avenue. This recommendation is based on the 2013 sediment supply conditions, and also accounts for the decrease in sediment supply anticipated as a result of the construction of the on-channel detention basin at Constitution Avenue.

F. PUBLIC MAINTENANCE NEEDS The City will own or will maintain drainage easements for the project area. A O&M plan will be developed after construction is completed.


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V. CHANNEL, STRUCTURE, AND UTILITY CROSSING DESIGN

A. COMPLIANCE WITH OTHER STUDIES This project was designed in compliance with the 2013 Master Plan. The Master Plan recommendations included maintaining a stable channel slope of 0.4%.

B. HYDRAULIC CRITRIA Hydraulic criteria applied are consistent with the City, and UDFCD Drainage Criteria Manuals, as well as CDOT requirements. Reference criteria are noted in the calculations provided in Appendix B.

C. SITE CONSTRAINTS This project is bounded to the north and south by existing grade control structures. Because the project does not lower the channel invert elevation, utility crossings of the channel did not provide a constraint to the project, however the east abutment location was set based on the vicinity of a 30-inch sanitary sewer main. Existing wetlands were documented within the project reach as part of this study, and as described in more detail in the delineation report included in the overall project submittal.

D. MAJOR CHANNEL COMPONENTS AND ATRIBUTES The 2013 Master Plan recommended a stable channel longitudinal slope of 0.4%. This channel slope has been maintained in the proposed channel improvements. Wherever possible, active channel side slopes are graded to be flatter than 3-ft horizontal to 1-ft vertical (3:1). Exposed riprap or an erosion control blanket will be used on any constructed slopes that are 3:1 or steeper. The trail included on the east bank of the channel has been designed to allow for future development as a greenway trail, with longitudinal slopes complying with City requirements. This project will formalize the trail by paving it, however public access will not be provided to the trail at this time. The trail elevation has been set at an elevation above the 10-year flow event water surface elevation in the channel.

E. MAJOR DROP STRUCTURE COMPONENTS AND ATTRIBUTES No drop structures are included with this project.

F. MAJOR COMPONENTS AND ATRIBUTES Major channel components are discussed in other sections of this report.

G. MAJOR DRAINAGE STRUCTURE COMPONENTS AND ATRIBUTES Riprap abutment slope protection and a sloped grouted boulder trail protection have been included to protect key project components during the 100-year, 200-year, and/or 500-year storm events.


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H. HYDRAULIC ANALYSIS – ASSUMPTIONS AND RESULTS The project reach was modeled using HEC-RAS modeling software. A copy of the hydraulic results (tabular and cross section) is included in Appendix A of this document. Subcritical flow was used for floodplain and scour modeling. Mixed flow conditions were also analyzed, but do not change the results in the design locations.

a. Manning’s n-Values Manning’s n-values were selected based on guidance from the HEC-RAS Hydraulic Reference Manual. Those values are summarized in Table 2 below.

Table 2. Summary of Manning's n-values in model

Manning’s n-value Description

0.012 Concrete trail, clean

0.016 Asphalt roads

0.03 Sandy, clean channel bottom

0.04 Riprap and sloped grouted boulder side slopes

0.067 Grouted stepped boulder drops

0.08 Dense vegetation in the overbanks

b. Contraction and Expansion Coefficients A contraction coefficient of 0.1 and an expansion coefficient of 0.3 were used for all channel cross sections This was not altered for the sections adjacent to the bridge because there is no contraction or expansion at the bridge.

c. Bridge Modeling For both the existing and proposed conditions models, the momentum low flow calculation is selected by HEC-RAS as the controlling flow condition. A drag coefficient of 1.2 is used for the 3-ft diameter circular piers proposed for the replacement bridge. The existing bridge has 2-ft wide triangular nose piers, and a coefficient of drag of 1.0 was selected to model these piers. Because the existing bridge is oversized for the current channel conditions, ineffective flow areas were defined on the west/right bank to reflect the active flow area underneath the bride. These areas were set based on the anticipated expansion of flow underneath the bridge from the western bank. The same ineffective flow areas were utilized for the proposed conditions model; however, the bridge has been sized to minimize expansion and contraction through the bridge, and the ineffective flow areas generally do not provide much reduction in effective flow areas for the proposed conditions model.

d. Boundary Conditions The hydraulic model for this project was appended to the upstream end of the West Fork Sand Creek to East Platte Avenue bridge project, which provided the downstream reach limits.


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e. Hydraulic Modeling – Proposed and Existing Conditions A proposed conditions model was developed based upon the existing ground survey for the project area as well as design parameters provided by HDR staff. Based on evolving design requirements, a conservative hydraulic model was developed based upon comparing the proposed conditions 100-year water surface elevations against the published regulatory water surface elevations for the project area. The bridge opening was widened from the originally proposed 240-ft width in order to accommodate the additional losses associated with a four-span bridge design and to allow for fill placed within the channel against the western abutment. During review of the 30% design submittal, RESPEC further refined the hydraulic models to compare the proposed conditions water surface elevations against the corrected effective or existing conditions 100-year water surface elevations. The existing conditions model accounts for changes in the channel geometry since the regulatory model was performed, including fill placed adjacent to the northwest abutment of the bridge, and the installation of grade control structures up and downstream of the bridge. The existing Platte Avenue bridge was modeled based on photos of the site and the project survey. It was verified with the Master Plan model. The Master Plan hydraulic model is not regulatory, and was not used for any purpose except to verify assumptions made in the proposed and existing conditions models. Ineffective flow areas are represented through the bridge based on the upstream fill slope. The upstream cross section for the existing and proposed conditions hydraulic model is maintained in the same location to allow for accurate comparisons of 100-year water surface elevations. A map showing the cross-section locations is included as an attachment to this document. The hydraulic modeling results for the proposed and existing conditions models are shown in Table 3. The modeling shows no rise in the water surface elevations from the existing to the proposed conditions bridge, and a maximum decrease in water surface elevation of 0.5 feet at the upstream face of the bridge.

Table 3. Comparison of Water Surface Elevations – 100-year flows

Cross Section ID Regulatory WSEL Existing WSEL Proposed WSEL Proposed - Existing WSEL

275+97 (u/s drop crest) 6186.73 6186.73 0.00

275+54 (u/s drop toe) 6182.47 6182.40 -0.07

275+12 6181.98 6181.84 -0.14

273+80 6181.37 6181.18 -0.19

Ai – not in model 6181.2

273+00 (BR U) 6180.66 6180.37 -0.29

273+00 (BR D) 6179.79 6178.44 -1.35

AH – not in model 6180.9

271.93 6178.46 6178.22 -0.24

271+67 6178.00 6178.00 0.00

271+47 6178.19 6178.19 0.00


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The proposed channel conditions for both bridge configurations result in zero rise when compared against the regulatory base flood elevations (BFEs). The average depth of flow for the 100-year event within the channel is approximately 6-ft. Channel velocities range between 6 and 7 ft/s through the bridge. Froude numbers range between 0.5-0.7 through the bridge section. A zero-rise floodplain development permit will be obtained for this project. A Letter of Map Revision (LOMR) will follow the construction of the bridge to provide a comprehensive floodplain between West Fork Sand Creek and just upstream of East Platte Avenue.

I. RIPRAP DESIGN Riprap protection will be used for the western abutment and was sized based upon several design constraints. Riprap calculations, criteria, and selection procedures are discussed in greater detail in the Technical Memorandum included in Appendix B of this document. Riprap abutment protection is recommended to be 18” D50, based primarily on the urban location of the bridge and the potential for vandalism. Riprap is not recommended for pier protection; the piers will be designed to withstand the anticipated pier scour.

J. STABILITY ANALYSIS The 2013 Drainage Master Plan for the project reach recommended a 0.4% stable channel slope based upon channel bed material grain size distributions, upstream sediment supply and a 1.5-yr storm event flow rate. The FHWA Hydraulic Engineering Circular 20 was used to determine sediment capacity values, and SAMWin v. 1.0 was used to determine sediment supply to the system. Based on the lack of sediment supply from upstream and the relative mobility of the channel bed material, a relatively flat equilibrium channel longitudinal slope of 0.4% was recommended for the reach of Sand Creek between Airport Road and East Platte Avenue.

K. IMPROVEMENT DESIGN Side slope lining and channel geometry have been discussed in other sections of this report. The proposed channel improvements have been designed to contain the 100-year flood and remain below the regulatory floodplain elevations. Based on the mobility of the channel, a low flow channel will not be constructed, but riprap protection may be provided to maintain low flows within the constraints of the channel banks and bridge abutments. Channel side slopes outside of the bridge will be limited to 3:1 or flatter. The abutment slope inside the bridge section will be 2:1. This results in average depths of flow of 6 feet for the 100-year storm event, with velocities of approximately 6 to 7 ft/s.

VI. PHASING

A. GENERAL TIMELINE The design of this project is complete. Additional timeline discussion is included in the overall project submittal.


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Target deadlines are as follows: / Construction – Quarter 4, 2018 - Quarter 4, 2020

/ Final Close Out – Quarter 3, 2021

B. MAJOR FACILITY TIMING CONSTRAINTS Spring runoff flow conditions provide the most critical and stringent timing constraints on the project, though the exact timing and flow conditions cannot be predicted.

C. ORDER OF CONSTRUCTION The order of construction will be determined as construction nears.

VII. SUMMARY

The East Platte Avenue Bridge Replacement Over Sand Creek project implements the replacement of the East Platte Avenue crossing over Sand Creek. This channel design submittal reflects final design. The design of the East Platte Avenue bridge replacement complies with the Drainage Basin Planning Study and the Master Plan for Sand Creek. The channel design provides stable channel conditions and maintains the floodplain elevations below the regulatory BFEs. The 100-year floodplain associated with the adjacent areas and downstream properties will not be adversely affected by the improvements proposed in this project. The channel improvements have been designed to increase safety and to be an amenity for the City of Colorado Springs.

final Channel Design Report rSI Project No. 3042

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VIII. REFERENCES

Ayres Associates 2013. Master Plan Sand Creek Channel Improvements Hancock Expressway to Platte Ave. East Fork to S Powers Blvd. and West Fork to Wooten Road. Prepared for City of Colorado Springs, El Paso County, CO. City of Colorado Springs 2014. Drainage Criteria Manual Volumes 1 and 2. Colorado Springs, CO. FEMA 1999. Flood Insurance Study, El Paso County Colorado and Incorporated Areas. Colorado Springs, El Paso County, CO. Kiowa Engineering Corporation, 1996. Sand Creek Drainage Basin Planning Study Preliminary Design Report, City of Colorado Springs, El Paso County, Colorado. Prepared for City of Colorado Springs, El Paso County, CO. Urban Drainage and Flood Control District, 2015. Urban Stormwater Drainage Criteria Manual: Volumes 1, 2, and 3. Denver, CO. US Army Corps of Engineers, Hydrologic Engineering Center. Hydrologic Engineering Centers River Analysis System (HEC-RAS), ver. 4.1.0.

Final Channel Design Report rSI Project No. 3042

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APPENDIX A - HEC-RAS HYDRAULIC RESULTS

HEC-RAS Plan: ex-bridge River: Sand Creek Reach: CL SAND CREEKReach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl

(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) CL SAND CREEK 28377.18 1 YR 870.00 6189.77 6192.70 6192.70 6193.54 0.011453 7.34 118.46 72.12 1.01CL SAND CREEK 28377.18 1.5 YR 1280.00 6189.77 6193.25 6193.25 6194.23 0.010830 7.95 161.05 83.48 1.01CL SAND CREEK 28377.18 2 YR 1430.00 6189.77 6193.42 6193.42 6194.45 0.010735 8.15 175.45 86.99 1.01CL SAND CREEK 28377.18 10 YR 1890.00 6189.77 6193.90 6193.90 6195.05 0.010264 8.61 219.55 96.95 1.01CL SAND CREEK 28377.18 50 YR 3390.00 6189.77 6196.09 6196.96 0.003619 7.52 451.05 110.08 0.65CL SAND CREEK 28377.18 100 YR 4370.00 6189.77 6197.21 6198.10 0.002873 7.57 577.56 116.67 0.60CL SAND CREEK 28377.18 500 YR 6760.00 6189.77 6199.52 6200.45 0.002124 7.70 877.49 137.46 0.54

CL SAND CREEK 28261.16 1 YR 870.00 6189.34 6192.25 6192.61 0.003674 4.78 182.12 89.99 0.59CL SAND CREEK 28261.16 1.5 YR 1280.00 6189.34 6192.71 6193.22 0.004172 5.72 223.96 92.90 0.65CL SAND CREEK 28261.16 2 YR 1430.00 6189.34 6192.85 6193.42 0.004375 6.04 236.90 93.79 0.67CL SAND CREEK 28261.16 10 YR 1890.00 6189.34 6193.21 6193.96 0.005043 6.97 271.06 96.08 0.73CL SAND CREEK 28261.16 50 YR 4230.00 6189.34 6194.38 6194.35 6196.23 0.008479 10.90 388.20 103.71 0.99CL SAND CREEK 28261.16 100 YR 5670.00 6189.34 6195.22 6195.22 6197.41 0.008301 11.88 477.33 110.15 1.01CL SAND CREEK 28261.16 500 YR 9200.00 6189.34 6196.99 6196.99 6199.79 0.007681 13.43 685.19 123.88 1.01

CL SAND CREEK 28107.05 1 YR 870.00 6189.04 6191.43 6191.86 0.006595 5.23 166.42 112.02 0.76CL SAND CREEK 28107.05 1.5 YR 1280.00 6189.04 6191.87 6192.41 0.006802 5.86 218.37 126.69 0.79CL SAND CREEK 28107.05 2 YR 1430.00 6189.04 6192.02 6192.58 0.006806 6.01 237.96 133.52 0.79CL SAND CREEK 28107.05 10 YR 1890.00 6189.04 6192.37 6193.05 0.006666 6.61 285.85 139.66 0.81CL SAND CREEK 28107.05 50 YR 4230.00 6189.04 6193.81 6194.90 0.006105 8.39 504.43 165.78 0.85CL SAND CREEK 28107.05 100 YR 5670.00 6189.04 6194.45 6194.09 6195.77 0.006244 9.21 615.54 178.75 0.87CL SAND CREEK 28107.05 500 YR 9200.00 6189.04 6195.44 6195.44 6197.48 0.007983 11.49 800.76 198.49 1.01

CL SAND CREEK 27907.71 1 YR 870.00 6187.52 6189.44 6189.44 6190.09 0.012157 6.47 134.48 104.14 1.00CL SAND CREEK 27907.71 1.5 YR 1280.00 6187.52 6189.83 6189.83 6190.64 0.011487 7.25 176.55 109.85 1.01CL SAND CREEK 27907.71 2 YR 1430.00 6187.52 6189.96 6189.96 6190.83 0.011276 7.47 191.50 112.20 1.01CL SAND CREEK 27907.71 10 YR 1890.00 6187.52 6190.33 6190.33 6191.34 0.010867 8.05 234.64 118.78 1.01CL SAND CREEK 27907.71 50 YR 4230.00 6187.52 6191.81 6191.81 6193.39 0.008933 10.09 423.07 141.85 0.99CL SAND CREEK 27907.71 100 YR 5670.00 6187.52 6192.66 6192.66 6194.38 0.007377 10.57 557.44 198.91 0.93CL SAND CREEK 27907.71 500 YR 9200.00 6187.52 6194.22 6194.22 6196.05 0.005466 11.32 943.86 283.18 0.85

CL SAND CREEK 27866.22 1 YR 870.00 6182.82 6185.92 6186.11 0.008683 3.47 250.95 174.03 0.41CL SAND CREEK 27866.22 1.5 YR 1280.00 6182.82 6186.49 6186.74 0.008950 4.03 317.68 192.21 0.43CL SAND CREEK 27866.22 2 YR 1430.00 6182.82 6186.68 6186.96 0.009021 4.20 340.15 197.51 0.44CL SAND CREEK 27866.22 10 YR 1890.00 6182.82 6187.21 6187.55 0.009188 4.67 404.63 212.61 0.45CL SAND CREEK 27866.22 50 YR 4230.00 6182.82 6189.21 6189.84 0.009872 6.37 664.28 268.19 0.51CL SAND CREEK 27866.22 100 YR 5670.00 6182.82 6190.08 6190.88 0.010193 7.18 790.59 302.01 0.55CL SAND CREEK 27866.22 500 YR 9200.00 6182.82 6192.10 6189.61 6192.84 0.006800 7.21 1396.07 340.96 0.47





CL SAND CREEK 27512.09 1 YR 870.00 6175.54 6178.29 6178.51 0.009922 3.72 233.88 106.59 0.44CL SAND CREEK 27512.09 1.5 YR 1280.00 6175.54 6178.81 6179.11 0.011193 4.42 289.83 111.66 0.48CL SAND CREEK 27512.09 2 YR 1430.00 6175.54 6178.97 6179.30 0.011469 4.64 308.37 112.38 0.49CL SAND CREEK 27512.09 10 YR 1890.00 6175.54 6179.42 6179.85 0.012299 5.25 359.74 114.36 0.52CL SAND CREEK 27512.09 50 YR 4230.00 6175.54 6181.16 6182.03 0.015042 7.49 564.83 125.66 0.61CL SAND CREEK 27512.09 100 YR 5670.00 6175.54 6181.98 6183.10 0.016245 8.51 666.40 137.52 0.65CL SAND CREEK 27512.09 500 YR 9200.00 6175.54 6183.68 6185.35 0.017731 10.39 885.56 161.81 0.71

CL SAND CREEK 27380 1 YR 870.00 6175.17 6177.83 6176.86 6178.02 0.001882 3.42 254.49 126.17 0.42

HEC-RAS Plan: ex-bridge River: Sand Creek Reach: CL SAND CREEK (Continued)Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl

(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) CL SAND CREEK 27380 1.5 YR 1280.00 6175.17 6178.30 6177.24 6178.56 0.002096 4.08 313.80 129.21 0.46CL SAND CREEK 27380 2 YR 1430.00 6175.17 6178.46 6177.37 6178.74 0.002135 4.28 334.29 129.89 0.47CL SAND CREEK 27380 10 YR 1890.00 6175.17 6178.88 6177.71 6179.25 0.002279 4.85 389.93 131.73 0.50CL SAND CREEK 27380 50 YR 4230.00 6175.17 6180.56 6179.09 6181.29 0.002669 6.85 617.36 139.00 0.57CL SAND CREEK 27380 100 YR 5670.00 6175.17 6181.37 6179.79 6182.31 0.002822 7.75 731.72 142.51 0.60CL SAND CREEK 27380 500 YR 9200.00 6175.17 6183.10 6181.28 6184.45 0.003051 9.32 986.87 154.05 0.65

CL SAND CREEK 27300 Bridge






CL SAND CREEK 27005.2* 1 YR 870.00 6165.91 6167.85 6168.03 0.002641 3.42 254.73 163.65 0.48CL SAND CREEK 27005.2* 1.5 YR 1280.00 6165.91 6168.25 6168.50 0.002863 3.97 322.38 175.44 0.52CL SAND CREEK 27005.2* 2 YR 1430.00 6165.91 6168.39 6168.65 0.002856 4.14 345.57 176.37 0.52CL SAND CREEK 27005.2* 10 YR 1890.00 6165.91 6168.76 6169.08 0.002849 4.59 411.33 179.00 0.53CL SAND CREEK 27005.2* 50 YR 4230.00 6165.91 6170.21 6170.81 0.002889 6.23 678.82 188.52 0.58CL SAND CREEK 27005.2* 100 YR 5670.00 6165.91 6170.90 6171.66 0.002966 7.00 810.33 192.70 0.60CL SAND CREEK 27005.2* 500 YR 9200.00 6165.91 6172.21 6173.36 0.003290 8.61 1068.26 200.64 0.66





(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) CL SAND CREEK 26965.48 1 YR 870.00 6165.75 6167.80 6167.91 0.006948 2.64 329.01 191.17 0.36CL SAND CREEK 26965.48 1.5 YR 1280.00 6165.75 6168.20 6168.36 0.007539 3.15 406.75 193.43 0.38CL SAND CREEK 26965.48 2 YR 1430.00 6165.75 6168.34 6168.51 0.007711 3.31 432.49 194.18 0.39CL SAND CREEK 26965.48 10 YR 1890.00 6165.75 6168.71 6168.93 0.008144 3.74 505.22 196.26 0.41CL SAND CREEK 26965.48 50 YR 4230.00 6165.75 6170.20 6170.63 0.009208 5.26 803.59 204.57 0.47CL SAND CREEK 26965.48 100 YR 5670.00 6165.75 6170.91 6171.46 0.009688 5.96 951.26 208.57 0.49CL SAND CREEK 26965.48 500 YR 9200.00 6165.75 6172.27 6173.13 0.011061 7.42 1240.73 217.60 0.55


CL SAND CREEK 26962.8* 1 YR 870.00 6165.74 6167.54 6167.85 0.026383 4.47 194.71 140.47 0.67CL SAND CREEK 26962.8* 1.5 YR 1280.00 6165.74 6167.83 6168.29 0.032173 5.41 236.55 148.59 0.76CL SAND CREEK 26962.8* 2 YR 1430.00 6165.74 6167.92 6168.43 0.034209 5.72 249.87 151.09 0.78CL SAND CREEK 26962.8* 10 YR 1890.00 6165.74 6168.17 6167.97 6168.84 0.039254 6.55 288.68 158.14 0.85CL SAND CREEK 26962.8* 50 YR 4230.00 6165.74 6169.18 6169.18 6170.49 0.048921 9.17 461.22 179.65 1.01CL SAND CREEK 26962.8* 100 YR 5670.00 6165.74 6169.78 6169.78 6171.31 0.045973 9.94 570.69 188.08 1.01CL SAND CREEK 26962.8* 500 YR 9200.00 6165.74 6171.01 6171.01 6172.96 0.042004 11.22 819.77 209.81 1.00

CL SAND CREEK 26961.5* 1 YR 870.00 6165.73 6167.28 6167.28 6167.78 0.066686 5.70 152.58 153.27 1.01CL SAND CREEK 26961.5* 1.5 YR 1280.00 6165.73 6167.58 6167.58 6168.22 0.062397 6.40 199.93 160.55 1.01CL SAND CREEK 26961.5* 2 YR 1430.00 6165.73 6167.68 6167.68 6168.36 0.060960 6.63 215.65 161.43 1.01CL SAND CREEK 26961.5* 10 YR 1890.00 6165.73 6167.96 6167.96 6168.77 0.057715 7.23 261.32 164.66 1.01CL SAND CREEK 26961.5* 50 YR 4230.00 6165.73 6169.13 6169.13 6170.35 0.050109 8.85 478.04 199.69 1.01CL SAND CREEK 26961.5* 100 YR 5670.00 6165.73 6169.67 6169.67 6171.12 0.046439 9.66 586.79 202.72 1.00CL SAND CREEK 26961.5* 500 YR 9200.00 6165.73 6170.78 6170.78 6172.76 0.042620 11.28 815.33 208.94 1.01







CL SAND CREEK 26885.0* 1 YR 870.00 6155.59 6157.48 6157.73 0.003109 4.00 217.29 124.05 0.53


(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) CL SAND CREEK 26885.0* 1.5 YR 1280.00 6155.59 6157.93 6158.27 0.003233 4.67 274.18 127.93 0.56CL SAND CREEK 26885.0* 2 YR 1430.00 6155.59 6158.08 6158.45 0.003261 4.87 293.51 129.26 0.57CL SAND CREEK 26885.0* 10 YR 1890.00 6155.59 6158.53 6158.98 0.003228 5.36 352.60 133.44 0.58CL SAND CREEK 26885.0* 50 YR 4230.00 6155.59 6160.21 6161.00 0.003509 7.11 594.88 156.70 0.64CL SAND CREEK 26885.0* 100 YR 5670.00 6155.59 6161.00 6161.96 0.003521 7.86 721.29 163.72 0.66CL SAND CREEK 26885.0* 500 YR 9200.00 6155.59 6162.61 6163.94 0.003472 9.26 993.05 173.84 0.68










CL SAND CREEK 26700.43 1 YR 870.00 6154.83 6157.22 6157.35 0.006174 2.89 301.11 140.44 0.35CL SAND CREEK 26700.43 1.5 YR 1280.00 6154.83 6157.65 6157.85 0.007434 3.53 362.42 143.64 0.39


(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) CL SAND CREEK 26700.43 2 YR 1430.00 6154.83 6157.80 6158.02 0.007735 3.72 383.96 144.75 0.40CL SAND CREEK 26700.43 10 YR 1890.00 6154.83 6158.26 6158.53 0.008156 4.19 451.20 148.27 0.42CL SAND CREEK 26700.43 50 YR 4230.00 6154.83 6159.93 6160.48 0.010134 5.96 709.26 161.03 0.50CL SAND CREEK 26700.43 100 YR 5670.00 6154.83 6160.69 6161.41 0.011126 6.80 833.98 166.64 0.54CL SAND CREEK 26700.43 500 YR 9200.00 6154.83 6162.27 6163.34 0.012540 8.32 1106.13 178.27 0.59

CL SAND CREEK 26699.1* 1 YR 870.00 6154.80 6157.13 6157.33 0.010994 3.63 239.63 122.39 0.46CL SAND CREEK 26699.1* 1.5 YR 1280.00 6154.80 6157.51 6157.82 0.013581 4.45 287.92 127.07 0.52CL SAND CREEK 26699.1* 2 YR 1430.00 6154.80 6157.65 6157.99 0.014194 4.68 305.28 128.75 0.54CL SAND CREEK 26699.1* 10 YR 1890.00 6154.80 6158.08 6158.50 0.014874 5.22 361.74 134.04 0.56CL SAND CREEK 26699.1* 50 YR 4230.00 6154.80 6159.61 6160.43 0.018251 7.27 581.87 152.86 0.66CL SAND CREEK 26699.1* 100 YR 5670.00 6154.80 6160.31 6161.35 0.019905 8.21 690.68 161.21 0.70CL SAND CREEK 26699.1* 500 YR 9200.00 6154.80 6161.81 6160.71 6163.28 0.020696 9.74 944.08 175.08 0.74

CL SAND CREEK 26697.8* 1 YR 870.00 6154.78 6156.92 6157.29 0.026374 4.90 177.40 111.30 0.68CL SAND CREEK 26697.8* 1.5 YR 1280.00 6154.78 6157.15 6157.76 0.038358 6.30 203.33 116.14 0.84CL SAND CREEK 26697.8* 2 YR 1430.00 6154.78 6157.19 6157.05 6157.92 0.044362 6.85 208.74 117.12 0.90CL SAND CREEK 26697.8* 10 YR 1890.00 6154.78 6157.44 6157.44 6158.42 0.053113 7.94 237.98 122.39 1.00CL SAND CREEK 26697.8* 50 YR 4230.00 6154.78 6158.89 6158.89 6160.34 0.047294 9.66 437.76 153.55 1.01CL SAND CREEK 26697.8* 100 YR 5670.00 6154.78 6159.54 6159.54 6161.25 0.043972 10.49 540.60 158.59 1.00CL SAND CREEK 26697.8* 500 YR 9200.00 6154.78 6160.90 6160.90 6163.16 0.040201 12.08 761.54 168.58 1.00








CL SAND CREEK 26614.8* 1 YR 870.00 6143.89 6146.82 6147.12 0.003164 4.39 198.40 99.71 0.55CL SAND CREEK 26614.8* 1.5 YR 1280.00 6143.89 6147.38 6147.77 0.003112 5.00 255.95 104.19 0.56CL SAND CREEK 26614.8* 2 YR 1430.00 6143.89 6147.56 6147.98 0.003103 5.20 275.20 105.53 0.57


(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) CL SAND CREEK 26614.8* 10 YR 1890.00 6143.89 6148.05 6148.57 0.003181 5.77 327.33 109.06 0.59CL SAND CREEK 26614.8* 50 YR 4230.00 6143.89 6149.80 6150.79 0.003742 8.00 528.92 121.78 0.68CL SAND CREEK 26614.8* 100 YR 5670.00 6143.89 6150.64 6151.88 0.003929 8.94 634.07 127.92 0.71CL SAND CREEK 26614.8* 500 YR 9200.00 6143.89 6152.42 6154.11 0.004173 10.45 880.20 146.81 0.75







CL SAND CREEK 26465.9* 1 YR 870.00 6144.07 6146.46 6146.79 0.003432 4.56 190.68 96.35 0.57CL SAND CREEK 26465.9* 1.5 YR 1280.00 6144.07 6146.96 6147.40 0.003784 5.33 240.11 103.31 0.62CL SAND CREEK 26465.9* 2 YR 1430.00 6144.07 6147.11 6147.60 0.003905 5.58 256.32 105.46 0.63CL SAND CREEK 26465.9* 10 YR 1890.00 6144.07 6147.52 6148.14 0.004301 6.29 300.63 111.13 0.67CL SAND CREEK 26465.9* 50 YR 4230.00 6144.07 6148.92 6150.18 0.006055 9.01 469.49 130.63 0.84CL SAND CREEK 26465.9* 100 YR 5670.00 6144.07 6149.71 6149.24 6151.21 0.006005 9.84 576.30 139.54 0.85CL SAND CREEK 26465.9* 500 YR 9200.00 6144.07 6151.34 6150.76 6153.32 0.005576 11.31 813.59 150.82 0.86

CL SAND CREEK 26455.8* 1 YR 870.00 6144.02 6146.08 6145.96 6146.70 0.009425 6.33 137.46 90.85 0.91CL SAND CREEK 26455.8* 1.5 YR 1280.00 6144.02 6146.50 6146.44 6147.31 0.009894 7.19 178.15 100.92 0.95CL SAND CREEK 26455.8* 2 YR 1430.00 6144.02 6146.65 6146.58 6147.50 0.009833 7.39 193.39 104.46 0.96CL SAND CREEK 26455.8* 10 YR 1890.00 6144.02 6147.09 6147.00 6148.04 0.009287 7.83 241.49 114.74 0.95CL SAND CREEK 26455.8* 50 YR 4230.00 6144.02 6148.85 6148.48 6150.12 0.006504 9.06 467.04 136.12 0.86CL SAND CREEK 26455.8* 100 YR 5670.00 6144.02 6149.66 6149.19 6151.14 0.006009 9.79 579.31 141.40 0.85CL SAND CREEK 26455.8* 500 YR 9200.00 6144.02 6151.30 6153.25 0.005479 11.21 820.90 152.14 0.85


CL SAND CREEK 26435.64 1 YR 870.00 6143.94 6146.22 6146.40 0.008566 3.37 258.20 122.06 0.41CL SAND CREEK 26435.64 1.5 YR 1280.00 6143.94 6146.74 6146.98 0.009199 3.97 322.32 125.49 0.44CL SAND CREEK 26435.64 2 YR 1430.00 6143.94 6146.91 6147.18 0.009391 4.16 343.62 126.61 0.45CL SAND CREEK 26435.64 10 YR 1890.00 6143.94 6147.39 6147.72 0.009829 4.67 404.84 129.78 0.47


(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) CL SAND CREEK 26435.64 50 YR 4230.00 6143.94 6149.15 6149.82 0.011817 6.57 643.76 141.45 0.54CL SAND CREEK 26435.64 100 YR 5670.00 6143.94 6149.98 6150.83 0.012679 7.43 763.38 146.95 0.57CL SAND CREEK 26435.64 500 YR 9200.00 6143.94 6151.66 6152.92 0.014026 9.01 1020.65 158.14 0.63

CL SAND CREEK 26434.3* 1 YR 870.00 6143.94 6145.86 6145.68 6146.34 0.041771 5.57 156.13 114.37 0.84CL SAND CREEK 26434.3* 1.5 YR 1280.00 6143.94 6146.44 6146.08 6146.94 0.029628 5.69 225.15 123.56 0.74CL SAND CREEK 26434.3* 2 YR 1430.00 6143.94 6146.61 6146.21 6147.13 0.027633 5.80 246.67 124.71 0.73CL SAND CREEK 26434.3* 10 YR 1890.00 6143.94 6147.09 6146.55 6147.68 0.023847 6.14 308.04 127.93 0.70CL SAND CREEK 26434.3* 50 YR 4230.00 6143.94 6148.79 6149.77 0.021311 7.90 535.12 139.19 0.71CL SAND CREEK 26434.3* 100 YR 5670.00 6143.94 6149.58 6148.64 6150.78 0.021434 8.77 646.66 144.40 0.73CL SAND CREEK 26434.3* 500 YR 9200.00 6143.94 6151.20 6150.13 6152.86 0.021575 10.35 888.85 155.12 0.76









CL SAND CREEK 26371.0* 1 YR 870.00 6137.79 6139.75 6140.11 0.004707 4.86 179.14 104.36 0.65CL SAND CREEK 26371.0* 1.5 YR 1280.00 6137.79 6140.24 6140.71 0.004522 5.54 231.21 107.25 0.66CL SAND CREEK 26371.0* 2 YR 1430.00 6137.79 6140.40 6140.91 0.004503 5.76 248.31 108.18 0.67CL SAND CREEK 26371.0* 10 YR 1890.00 6137.79 6140.84 6141.47 0.004505 6.38 296.41 110.75 0.69CL SAND CREEK 26371.0* 50 YR 4230.00 6137.79 6142.55 6143.69 0.004599 8.54 495.42 120.82 0.74


(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) CL SAND CREEK 26371.0* 100 YR 5670.00 6137.79 6143.38 6144.78 0.004695 9.50 596.62 125.63 0.77CL SAND CREEK 26371.0* 500 YR 9200.00 6137.79 6145.10 6147.05 0.004722 11.19 822.39 135.75 0.80










CL SAND CREEK 25552.27 1 YR 870.00 6134.49 6136.48 6136.79 0.003638 4.48 194.04 105.00 0.58CL SAND CREEK 25552.27 1.5 YR 1280.00 6134.49 6136.93 6137.36 0.003956 5.30 241.64 108.35 0.63CL SAND CREEK 25552.27 2 YR 1430.00 6134.49 6137.07 6137.55 0.004040 5.55 257.70 109.46 0.64CL SAND CREEK 25552.27 10 YR 1890.00 6134.49 6137.48 6138.08 0.004301 6.25 302.35 112.48 0.67CL SAND CREEK 25552.27 50 YR 4230.00 6134.49 6138.98 6140.18 0.005285 8.83 479.27 123.72 0.79CL SAND CREEK 25552.27 100 YR 5670.00 6134.49 6139.66 6141.22 0.005831 10.02 566.07 130.02 0.85


(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) CL SAND CREEK 25552.27 500 YR 9200.00 6134.49 6140.97 6140.77 6143.34 0.007002 12.36 744.31 142.90 0.95




CL SAND CREEK 25337.9* 1 YR 870.00 6133.43 6135.76 6136.10 0.004410 4.67 186.32 109.90 0.63CL SAND CREEK 25337.9* 1.5 YR 1280.00 6133.43 6136.22 6136.67 0.004577 5.35 239.08 118.06 0.66CL SAND CREEK 25337.9* 2 YR 1430.00 6133.43 6136.36 6136.85 0.004673 5.58 256.09 120.57 0.68CL SAND CREEK 25337.9* 10 YR 1890.00 6133.43 6136.75 6137.35 0.004968 6.22 303.86 127.38 0.71CL SAND CREEK 25337.9* 50 YR 4230.00 6133.43 6138.19 6137.67 6139.28 0.005741 8.37 505.59 151.29 0.81CL SAND CREEK 25337.9* 100 YR 5670.00 6133.43 6138.92 6138.37 6140.22 0.005638 9.16 618.72 159.23 0.82CL SAND CREEK 25337.9* 500 YR 9200.00 6133.43 6140.36 6139.79 6142.13 0.005482 10.69 870.13 196.36 0.84








(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft)







CL SAND CREEK 25248.2* 1 YR 870.00 6128.28 6131.22 6131.48 0.002399 4.08 213.48 97.57 0.49CL SAND CREEK 25248.2* 1.5 YR 1280.00 6128.28 6131.71 6132.08 0.002861 4.86 263.51 105.60 0.54CL SAND CREEK 25248.2* 2 YR 1430.00 6128.28 6131.87 6132.28 0.003025 5.09 280.77 109.27 0.56CL SAND CREEK 25248.2* 10 YR 1890.00 6128.28 6132.31 6132.82 0.003349 5.72 330.24 116.42 0.60CL SAND CREEK 25248.2* 50 YR 4230.00 6128.28 6134.03 6134.96 0.003798 7.78 543.99 132.74 0.68CL SAND CREEK 25248.2* 100 YR 5670.00 6128.28 6134.81 6135.99 0.003998 8.72 650.14 138.63 0.71CL SAND CREEK 25248.2* 500 YR 9200.00 6128.28 6136.46 6135.29 6138.12 0.004174 10.33 890.78 151.96 0.75





(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) CL SAND CREEK 25208.32 1 YR 870.00 6128.18 6130.12 6130.45 0.004036 4.62 188.47 105.61 0.61CL SAND CREEK 25208.32 1.5 YR 1280.00 6128.18 6130.56 6131.02 0.004305 5.41 236.53 109.51 0.65CL SAND CREEK 25208.32 2 YR 1430.00 6128.18 6130.71 6131.21 0.004378 5.66 252.72 110.79 0.66CL SAND CREEK 25208.32 10 YR 1890.00 6128.18 6131.13 6131.75 0.004541 6.31 299.40 114.42 0.69CL SAND CREEK 25208.32 50 YR 4230.00 6128.18 6132.76 6133.88 0.004911 8.50 497.42 128.65 0.76CL SAND CREEK 25208.32 100 YR 5670.00 6128.18 6133.53 6134.92 0.005066 9.45 599.94 135.43 0.79CL SAND CREEK 25208.32 500 YR 9200.00 6128.18 6135.11 6137.04 0.005265 11.16 824.23 148.97 0.84










CL SAND CREEK 24695.9* 1 YR 870.00 6126.12 6127.80 6128.17 0.029077 4.88 178.39 121.57 0.71


(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) CL SAND CREEK 24695.9* 1.5 YR 1280.00 6126.12 6128.19 6128.69 0.030611 5.65 226.58 128.69 0.75CL SAND CREEK 24695.9* 2 YR 1430.00 6126.12 6128.31 6128.85 0.031198 5.90 242.50 130.98 0.76CL SAND CREEK 24695.9* 10 YR 1890.00 6126.12 6128.68 6129.33 0.030909 6.50 290.93 134.89 0.78CL SAND CREEK 24695.9* 50 YR 4230.00 6126.12 6130.09 6131.24 0.030639 8.63 490.31 147.28 0.83CL SAND CREEK 24695.9* 100 YR 5670.00 6126.12 6130.75 6132.19 0.031115 9.60 590.49 152.67 0.86CL SAND CREEK 24695.9* 500 YR 9200.00 6126.12 6132.21 6134.16 0.030191 11.20 821.32 164.48 0.88










CL SAND CREEK 24626.1* 1 YR 870.00 6121.16 6123.23 6123.16 6123.85 0.010397 6.30 138.13 98.83 0.94CL SAND CREEK 24626.1* 1.5 YR 1280.00 6121.16 6123.68 6123.58 6124.43 0.009547 6.93 184.76 107.43 0.93


(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) CL SAND CREEK 24626.1* 2 YR 1430.00 6121.16 6123.89 6123.73 6124.63 0.008304 6.91 206.99 108.79 0.88CL SAND CREEK 24626.1* 10 YR 1890.00 6121.16 6124.42 6124.10 6125.20 0.006786 7.09 266.70 115.90 0.82CL SAND CREEK 24626.1* 50 YR 4230.00 6121.16 6126.10 6125.61 6127.33 0.005816 8.89 475.75 130.69 0.82CL SAND CREEK 24626.1* 100 YR 5670.00 6121.16 6126.90 6126.34 6128.37 0.005673 9.74 582.03 136.68 0.83CL SAND CREEK 24626.1* 500 YR 9200.00 6121.16 6128.54 6127.89 6130.51 0.005483 11.27 816.66 150.04 0.85

CL SAND CREEK 24616.1* 1 YR 870.00 6121.18 6123.18 6123.74 0.007924 6.00 144.90 90.84 0.84CL SAND CREEK 24616.1* 1.5 YR 1280.00 6121.18 6123.55 6123.44 6124.34 0.009300 7.14 179.35 97.79 0.93CL SAND CREEK 24616.1* 2 YR 1430.00 6121.18 6123.66 6123.58 6124.53 0.009702 7.49 190.99 100.03 0.95CL SAND CREEK 24616.1* 10 YR 1890.00 6121.18 6124.01 6124.01 6125.09 0.010437 8.34 226.61 106.60 1.01CL SAND CREEK 24616.1* 50 YR 4230.00 6121.18 6125.59 6125.59 6127.22 0.008957 10.24 412.99 127.05 1.00CL SAND CREEK 24616.1* 100 YR 5670.00 6121.18 6126.32 6126.32 6128.26 0.008589 11.17 507.60 132.71 1.01CL SAND CREEK 24616.1* 500 YR 9200.00 6121.18 6127.87 6127.87 6130.39 0.007885 12.74 721.96 144.99 1.01






CL SAND CREEK 24501.27 1 YR 870.00 6113.20 6115.18 6115.06 6115.78 0.009044 6.18 140.76 93.43 0.89CL SAND CREEK 24501.27 1.5 YR 1280.00 6113.20 6115.99 6116.52 0.004973 5.83 219.53 101.40 0.70CL SAND CREEK 24501.27 2 YR 1430.00 6113.20 6116.28 6116.79 0.004242 5.75 248.84 104.21 0.66CL SAND CREEK 24501.27 10 YR 1890.00 6113.20 6116.91 6117.46 0.003596 5.97 316.49 110.42 0.62CL SAND CREEK 24501.27 50 YR 4230.00 6113.20 6118.98 6119.86 0.003023 7.54 564.34 127.55 0.62CL SAND CREEK 24501.27 100 YR 5670.00 6113.20 6120.08 6121.10 0.002652 8.14 708.88 135.33 0.60CL SAND CREEK 24501.27 500 YR 9200.00 6113.20 6122.39 6123.71 0.002194 9.27 1040.76 151.70 0.58



CL SAND CREEK 24330.02 1 YR 870.00 6112.31 6115.09 6115.41 0.001734 4.54 191.57 75.15 0.50CL SAND CREEK 24330.02 1.5 YR 1280.00 6112.31 6115.77 6116.20 0.001784 5.25 243.68 78.20 0.52CL SAND CREEK 24330.02 2 YR 1430.00 6112.31 6115.99 6116.46 0.001793 5.47 261.25 79.31 0.53


(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) CL SAND CREEK 24330.02 10 YR 1890.00 6112.31 6116.47 6117.07 0.002930 6.19 305.46 112.65 0.66CL SAND CREEK 24330.02 50 YR 4230.00 6112.31 6117.45 6117.44 6118.65 0.006811 8.79 483.43 202.87 0.99CL SAND CREEK 24330.02 100 YR 5670.00 6112.31 6117.96 6117.96 6119.42 0.006462 9.72 587.71 205.49 1.00CL SAND CREEK 24330.02 500 YR 9200.00 6112.31 6119.07 6119.07 6121.08 0.005806 11.41 819.14 211.19 1.00



HEC-RAS Plan: Proposed River: Sand Creek Reach: CL SAND CREEKReach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl

(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) CL SAND CREEK 28377.18 1 YR 870.00 6189.77 6192.70 6192.70 6193.54 0.011453 7.34 118.46 72.12 1.01CL SAND CREEK 28377.18 1.5 YR 1280.00 6189.77 6193.25 6193.25 6194.23 0.010830 7.95 161.05 83.48 1.01CL SAND CREEK 28377.18 2 YR 1430.00 6189.77 6193.42 6193.42 6194.45 0.010735 8.15 175.45 86.99 1.01CL SAND CREEK 28377.18 10 YR 1890.00 6189.77 6193.90 6193.90 6195.05 0.010264 8.61 219.55 96.95 1.01CL SAND CREEK 28377.18 50 YR 3390.00 6189.77 6196.09 6196.96 0.003619 7.52 451.05 110.08 0.65CL SAND CREEK 28377.18 100 YR 4370.00 6189.77 6197.21 6198.10 0.002873 7.57 577.56 116.67 0.60CL SAND CREEK 28377.18 200 YR 5280.00 6189.77 6198.21 6199.09 0.002521 7.52 702.15 129.93 0.57CL SAND CREEK 28377.18 500 YR 6760.00 6189.77 6199.52 6200.45 0.002124 7.70 877.49 137.46 0.54

CL SAND CREEK 28261.16 1 YR 870.00 6189.34 6192.25 6192.61 0.003674 4.78 182.12 89.99 0.59CL SAND CREEK 28261.16 1.5 YR 1280.00 6189.34 6192.71 6193.22 0.004175 5.72 223.91 92.90 0.65CL SAND CREEK 28261.16 2 YR 1430.00 6189.34 6192.85 6193.42 0.004372 6.04 236.95 93.79 0.67CL SAND CREEK 28261.16 10 YR 1890.00 6189.34 6193.21 6193.96 0.005043 6.97 271.06 96.08 0.73CL SAND CREEK 28261.16 50 YR 4230.00 6189.34 6194.38 6194.35 6196.23 0.008479 10.90 388.20 103.71 0.99CL SAND CREEK 28261.16 100 YR 5670.00 6189.34 6195.22 6195.22 6197.41 0.008301 11.88 477.33 110.15 1.01CL SAND CREEK 28261.16 200 YR 7054.00 6189.34 6195.96 6195.96 6198.41 0.008031 12.57 561.04 115.88 1.01CL SAND CREEK 28261.16 500 YR 9200.00 6189.34 6196.99 6196.99 6199.79 0.007681 13.43 685.19 123.88 1.01

CL SAND CREEK 28107.05 1 YR 870.00 6189.04 6191.43 6191.86 0.006595 5.23 166.42 112.02 0.76CL SAND CREEK 28107.05 1.5 YR 1280.00 6189.04 6191.88 6192.41 0.006775 5.85 218.74 126.86 0.79CL SAND CREEK 28107.05 2 YR 1430.00 6189.04 6192.02 6192.58 0.006782 6.00 238.22 133.55 0.79CL SAND CREEK 28107.05 10 YR 1890.00 6189.04 6192.37 6193.05 0.006661 6.61 285.92 139.67 0.81CL SAND CREEK 28107.05 50 YR 4230.00 6189.04 6193.81 6194.90 0.006105 8.39 504.43 165.78 0.85CL SAND CREEK 28107.05 100 YR 5670.00 6189.04 6194.45 6194.09 6195.77 0.006244 9.21 615.54 178.75 0.87CL SAND CREEK 28107.05 200 YR 7054.00 6189.04 6194.75 6194.66 6196.47 0.007625 10.52 670.40 184.82 0.97CL SAND CREEK 28107.05 500 YR 9200.00 6189.04 6195.44 6195.44 6197.48 0.007983 11.49 800.76 198.49 1.01

CL SAND CREEK 27907.71 1 YR 870.00 6187.52 6189.44 6189.44 6190.09 0.012157 6.47 134.48 104.14 1.00CL SAND CREEK 27907.71 1.5 YR 1280.00 6187.52 6189.82 6189.82 6190.64 0.011562 7.27 176.18 109.80 1.01CL SAND CREEK 27907.71 2 YR 1430.00 6187.52 6189.96 6189.96 6190.83 0.011341 7.48 191.12 112.13 1.01CL SAND CREEK 27907.71 10 YR 1890.00 6187.52 6190.33 6190.33 6191.34 0.010884 8.06 234.52 118.78 1.01CL SAND CREEK 27907.71 50 YR 4230.00 6187.52 6191.81 6191.81 6193.39 0.008933 10.09 423.07 141.85 0.99CL SAND CREEK 27907.71 100 YR 5670.00 6187.52 6192.66 6192.66 6194.38 0.007377 10.57 557.44 198.91 0.93CL SAND CREEK 27907.71 200 YR 7054.00 6187.52 6193.42 6193.42 6195.12 0.006013 10.70 725.70 258.18 0.86CL SAND CREEK 27907.71 500 YR 9200.00 6187.52 6194.22 6194.22 6196.05 0.005466 11.32 943.86 283.18 0.85

CL SAND CREEK 27866.22 1 YR 870.00 6182.82 6185.92 6186.11 0.008683 3.47 250.95 174.03 0.41CL SAND CREEK 27866.22 1.5 YR 1280.00 6182.82 6186.49 6186.74 0.008950 4.03 317.68 192.21 0.43CL SAND CREEK 27866.22 2 YR 1430.00 6182.82 6186.68 6186.96 0.009021 4.20 340.15 197.51 0.44CL SAND CREEK 27866.22 10 YR 1890.00 6182.82 6187.21 6187.55 0.009188 4.67 404.63 212.61 0.45CL SAND CREEK 27866.22 50 YR 4230.00 6182.82 6189.21 6189.84 0.009872 6.37 664.28 268.19 0.51CL SAND CREEK 27866.22 100 YR 5670.00 6182.82 6190.08 6190.88 0.010193 7.18 790.59 302.01 0.55CL SAND CREEK 27866.22 200 YR 7054.00 6182.82 6190.87 6191.75 0.009632 7.60 980.99 332.65 0.54CL SAND CREEK 27866.22 500 YR 9200.00 6182.82 6192.10 6189.61 6192.84 0.006800 7.21 1396.07 340.96 0.47





HEC-RAS Plan: Proposed River: Sand Creek Reach: CL SAND CREEK (Continued)Reach River Sta Profile Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope Vel Chnl Flow Area Top Width Froude # Chl

(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) CL SAND CREEK 27512.09 1 YR 870.00 6175.54 6178.01 6178.29 0.015009 4.26 204.26 103.68 0.53CL SAND CREEK 27512.09 1.5 YR 1280.00 6175.54 6178.55 6178.92 0.015259 4.89 261.76 109.25 0.56CL SAND CREEK 27512.09 2 YR 1430.00 6175.54 6178.73 6179.13 0.015387 5.09 280.91 111.05 0.56CL SAND CREEK 27512.09 10 YR 1890.00 6175.54 6179.20 6179.69 0.015553 5.66 334.00 113.37 0.58CL SAND CREEK 27512.09 50 YR 4230.00 6175.54 6180.99 6181.93 0.016919 7.78 543.76 123.16 0.65CL SAND CREEK 27512.09 100 YR 5670.00 6175.54 6181.84 6183.02 0.017656 8.74 648.55 135.46 0.68CL SAND CREEK 27512.09 200 YR 7054.00 6175.54 6182.54 6183.96 0.018375 9.56 737.89 145.70 0.70CL SAND CREEK 27512.09 500 YR 9200.00 6175.54 6183.49 6185.26 0.019371 10.69 860.69 159.50 0.74

CL SAND CREEK 27380 1 YR 870.00 6175.17 6177.60 6176.50 6177.78 0.001615 3.40 256.18 114.26 0.40CL SAND CREEK 27380 1.5 YR 1280.00 6175.17 6178.09 6176.89 6178.35 0.001877 4.09 312.61 117.78 0.44CL SAND CREEK 27380 2 YR 1430.00 6175.17 6178.24 6177.01 6178.53 0.001962 4.32 330.98 118.90 0.46CL SAND CREEK 27380 10 YR 1890.00 6175.17 6178.67 6177.38 6179.05 0.002193 4.94 382.50 122.00 0.49CL SAND CREEK 27380 50 YR 4230.00 6175.17 6180.34 6178.88 6181.12 0.002834 7.08 597.18 134.14 0.59CL SAND CREEK 27380 100 YR 5670.00 6175.17 6181.19 6179.64 6182.17 0.003004 7.96 712.46 140.22 0.62CL SAND CREEK 27380 200 YR 7054.00 6175.17 6181.89 6180.29 6183.06 0.003149 8.68 812.63 145.30 0.65CL SAND CREEK 27380 500 YR 9200.00 6175.17 6182.84 6181.20 6184.28 0.003341 9.64 954.18 152.17 0.68

CL SAND CREEK 27300 Bridge





CL SAND CREEK 27015.23 1 YR 870.00 6165.95 6167.93 6168.06 0.001559 2.88 301.87 168.23 0.38CL SAND CREEK 27015.23 1.5 YR 1280.00 6165.95 6168.34 6168.53 0.001727 3.44 371.84 171.33 0.41CL SAND CREEK 27015.23 2 YR 1430.00 6165.95 6168.48 6168.68 0.001778 3.62 394.91 172.35 0.42CL SAND CREEK 27015.23 10 YR 1890.00 6165.95 6168.85 6169.11 0.001912 4.11 459.90 175.17 0.45CL SAND CREEK 27015.23 50 YR 4230.00 6165.95 6170.32 6170.85 0.002276 5.84 724.15 185.03 0.52CL SAND CREEK 27015.23 100 YR 5670.00 6165.95 6171.01 6171.69 0.002437 6.64 854.02 189.32 0.55CL SAND CREEK 27015.23 200 YR 7054.00 6165.95 6171.57 6172.41 0.002607 7.34 961.40 192.79 0.58CL SAND CREEK 27015.23 500 YR 9200.00 6165.95 6172.34 6173.40 0.002835 8.28 1110.72 197.53 0.62

CL SAND CREEK 27005.2* 1 YR 870.00 6165.91 6167.85 6168.03 0.002641 3.42 254.73 163.65 0.48CL SAND CREEK 27005.2* 1.5 YR 1280.00 6165.91 6168.25 6168.50 0.002863 3.97 322.38 175.44 0.52CL SAND CREEK 27005.2* 2 YR 1430.00 6165.91 6168.39 6168.65 0.002856 4.14 345.57 176.37 0.52CL SAND CREEK 27005.2* 10 YR 1890.00 6165.91 6168.76 6169.08 0.002849 4.59 411.33 179.00 0.53CL SAND CREEK 27005.2* 50 YR 4230.00 6165.91 6170.21 6170.81 0.002889 6.23 678.82 188.52 0.58CL SAND CREEK 27005.2* 100 YR 5670.00 6165.91 6170.90 6171.66 0.002966 7.00 810.33 192.70 0.60CL SAND CREEK 27005.2* 200 YR 7054.00 6165.91 6171.46 6172.37 0.003100 7.68 918.34 196.06 0.63CL SAND CREEK 27005.2* 500 YR 9200.00 6165.91 6172.21 6173.36 0.003290 8.61 1068.26 200.64 0.66



(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) CL SAND CREEK 26995.3* 500 YR 9200.00 6165.87 6172.17 6173.33 0.003398 8.64 1065.27 204.30 0.67





CL SAND CREEK 26962.8* 1 YR 870.00 6165.74 6167.54 6167.85 0.026383 4.47 194.71 140.47 0.67CL SAND CREEK 26962.8* 1.5 YR 1280.00 6165.74 6167.83 6168.29 0.032173 5.41 236.55 148.59 0.76CL SAND CREEK 26962.8* 2 YR 1430.00 6165.74 6167.92 6168.43 0.034209 5.72 249.87 151.09 0.78CL SAND CREEK 26962.8* 10 YR 1890.00 6165.74 6168.17 6167.97 6168.84 0.039254 6.55 288.68 158.14 0.85CL SAND CREEK 26962.8* 50 YR 4230.00 6165.74 6169.18 6169.18 6170.49 0.048921 9.17 461.22 179.65 1.01CL SAND CREEK 26962.8* 100 YR 5670.00 6165.74 6169.78 6169.78 6171.31 0.045973 9.94 570.69 188.08 1.01CL SAND CREEK 26962.8* 200 YR 7054.00 6165.74 6170.35 6170.35 6172.01 0.044543 10.35 681.67 206.13 1.00CL SAND CREEK 26962.8* 500 YR 9200.00 6165.74 6171.01 6171.01 6172.96 0.042004 11.22 819.77 209.81 1.00

CL SAND CREEK 26961.5* 1 YR 870.00 6165.73 6167.28 6167.28 6167.78 0.066686 5.70 152.58 153.27 1.01CL SAND CREEK 26961.5* 1.5 YR 1280.00 6165.73 6167.58 6167.58 6168.22 0.062397 6.40 199.93 160.55 1.01CL SAND CREEK 26961.5* 2 YR 1430.00 6165.73 6167.68 6167.68 6168.36 0.060960 6.63 215.65 161.43 1.01CL SAND CREEK 26961.5* 10 YR 1890.00 6165.73 6167.96 6167.96 6168.77 0.057715 7.23 261.32 164.66 1.01CL SAND CREEK 26961.5* 50 YR 4230.00 6165.73 6169.13 6169.13 6170.35 0.050109 8.85 478.04 199.69 1.01CL SAND CREEK 26961.5* 100 YR 5670.00 6165.73 6169.67 6169.67 6171.12 0.046439 9.66 586.79 202.72 1.00CL SAND CREEK 26961.5* 200 YR 7054.00 6165.73 6170.12 6170.12 6171.80 0.045155 10.40 678.12 205.22 1.01CL SAND CREEK 26961.5* 500 YR 9200.00 6165.73 6170.78 6170.78 6172.76 0.042620 11.28 815.33 208.94 1.01





(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) CL SAND CREEK 26940.2* 500 YR 9200.00 6160.73 6167.10 6167.10 6169.26 0.041365 11.78 780.85 183.87 1.01











(cfs) (ft) (ft) (ft) (ft) (ft/ft) (ft/s) (sq ft) (ft) CL SAND CREEK 26751.26 500 YR 9200.00 6155.05 6162.42 6163.51 0.002473 8.35 1102.24 174.18 0.58






CL SAND CREEK 26699.1* 1 YR 870.00 6154.80 6157.13 6157.33 0.010994 3.63 239.63 122.39 0.46CL SAND CREEK 26699.1* 1.5 YR 1280.00 6154.80 6157.51 6157.82 0.013581 4.45 287.92 127.07 0.52CL SAND CREEK 26699.1* 2 YR 1430.00 6154.80 6157.65 6157.99 0.014194 4.68 305.28 128.75 0.54CL SAND CREEK 26699.1* 10 YR 1890.00 6154.80 6158.08 6158.50 0.014874 5.22 361.74 134.04 0.56CL SAND CREEK 26699.1* 50 YR 4230.00 6154.80 6159.61 6160.43 0.018251 7.27 581.87 152.86 0.66CL SAND CREEK 26699.1* 100 YR 5670.00 6154.80 6160.31 6161.35 0.019905 8.21 690.68 161.21 0.70CL SAND CREEK 26699.1* 200 YR 7054.00 6154.80 6160.93 6162.16 0.020562 8.88 794.20 168.67 0.72CL SAND CREEK 26699.1* 500 YR 9200.00 6154.80 6161.81 6160.71 6163.28 0.020696 9.74 944.08 175.08 0.74

CL SAND CREEK 26697.8* 1 YR 870.00 6154.78 6156.92 6157.29 0.026374 4.90 177.40 111.30 0.68CL SAND CREEK 26697.8* 1.5 YR 1280.00 6154.78 6157.15 6157.76 0.038358 6.30 203.33 116.14 0.84CL SAND CREEK 26697.8* 2 YR 1430.00 6154.78 6157.19 6157.05 6157.92 0.044362 6.85 208.74 117.12 0.90CL SAND CREEK 26697.8* 10 YR 1890.00 6154.78 6157.44 6157.44 6158.42 0.053113 7.94 237.98 122.39 1.00CL SAND CREEK 26697.8* 50 YR 4230.00 6154.78 6158.89 6158.89 6160.34 0.047294 9.66 437.76 153.55 1.01CL SAND CREEK 26697.8* 100 YR 5670.00 6154.78 6159.54 6159.54 6161.25 0.043972 10.49 540.60 158.59 1.00CL SAND CREEK 26697.8* 200 YR 7054.00 6154.78 6160.09 6160.09 6162.05 0.042582 11.22 628.83 162.65 1.01CL SAND CREEK 26697.8* 500 YR 9200.00 6154.78 6160.90 6160.90 6163.16 0.040201 12.08 761.54 168.58 1.00



















CL SAND CREEK 26465.9* 1 YR 870.00 6144.07 6146.46 6146.79 0.003432 4.56 190.68 96.35 0.57CL SAND CREEK 26465.9* 1.5 YR 1280.00 6144.07 6146.96 6147.40 0.003784 5.33 240.11 103.31 0.62CL SAND CREEK 26465.9* 2 YR 1430.00 6144.07 6147.11 6147.60 0.003905 5.58 256.32 105.46 0.63CL SAND CREEK 26465.9* 10 YR 1890.00 6144.07 6147.52 6148.14 0.004301 6.29 300.63 111.13 0.67CL SAND CREEK 26465.9* 50 YR 4230.00 6144.07 6148.92 6150.18 0.006055 9.01 469.49 130.63 0.84CL SAND CREEK 26465.9* 100 YR 5670.00 6144.07 6149.71 6149.24 6151.21 0.006005 9.84 576.30 139.54 0.85CL SAND CREEK 26465.9* 200 YR 7054.00 6144.07 6150.39 6149.87 6152.09 0.005798 10.47 673.97 144.72 0.85CL SAND CREEK 26465.9* 500 YR 9200.00 6144.07 6151.34 6150.76 6153.32 0.005576 11.31 813.59 150.82 0.86

CL SAND CREEK 26455.8* 1 YR 870.00 6144.02 6146.08 6145.96 6146.70 0.009425 6.33 137.46 90.85 0.91CL SAND CREEK 26455.8* 1.5 YR 1280.00 6144.02 6146.50 6146.44 6147.31 0.009894 7.19 178.15 100.92 0.95CL SAND CREEK 26455.8* 2 YR 1430.00 6144.02 6146.65 6146.58 6147.50 0.009833 7.39 193.39 104.46 0.96CL SAND CREEK 26455.8* 10 YR 1890.00 6144.02 6147.09 6147.00 6148.04 0.009287 7.83 241.49 114.74 0.95CL SAND CREEK 26455.8* 50 YR 4230.00 6144.02 6148.85 6148.48 6150.12 0.006504 9.06 467.04 136.12 0.86CL SAND CREEK 26455.8* 100 YR 5670.00 6144.02 6149.66 6149.19 6151.14 0.006009 9.79 579.31 141.40 0.85CL SAND CREEK 26455.8* 200 YR 7054.00 6144.02 6150.35 6152.03 0.005732 10.39 678.64 145.91 0.85CL SAND CREEK 26455.8* 500 YR 9200.00 6144.02 6151.30 6153.25 0.005479 11.21 820.90 152.14 0.85



CL SAND CREEK 26434.3* 1 YR 870.00 6143.94 6145.86 6145.68 6146.34 0.041771 5.57 156.13 114.37 0.84CL SAND CREEK 26434.3* 1.5 YR 1280.00 6143.94 6146.44 6146.08 6146.94 0.029628 5.69 225.15 123.56 0.74CL SAND CREEK 26434.3* 2 YR 1430.00 6143.94 6146.61 6146.21 6147.13 0.027633 5.80 246.67 124.71 0.73CL SAND CREEK 26434.3* 10 YR 1890.00 6143.94 6147.09 6146.55 6147.68 0.023847 6.14 308.04 127.93 0.70CL SAND CREEK 26434.3* 50 YR 4230.00 6143.94 6148.79 6149.77 0.021311 7.90 535.12 139.19 0.71CL SAND CREEK 26434.3* 100 YR 5670.00 6143.94 6149.58 6148.64 6150.78 0.021434 8.77 646.66 144.40 0.73CL SAND CREEK 26434.3* 200 YR 7054.00 6143.94 6150.27 6149.26 6151.65 0.021407 9.44 746.99 148.94 0.74CL SAND CREEK 26434.3* 500 YR 9200.00 6143.94 6151.20 6150.13 6152.86 0.021575 10.35 888.85 155.12 0.76

















CL SAND CREEK 26328.81 1 YR 870.00 6137.62 6139.56 6139.91 0.004237 4.78 181.94 100.13 0.63CL SAND CREEK 26328.81 1.5 YR 1280.00 6137.62 6140.03 6140.51 0.004393 5.57 229.68 103.10 0.66CL SAND CREEK 26328.81 2 YR 1430.00 6137.62 6140.18 6140.70 0.004454 5.83 245.40 104.05 0.67CL SAND CREEK 26328.81 10 YR 1890.00 6137.62 6140.60 6141.26 0.004620 6.52 289.97 106.72 0.70CL SAND CREEK 26328.81 50 YR 4230.00 6137.62 6142.23 6143.47 0.005189 8.97 471.72 116.98 0.79CL SAND CREEK 26328.81 100 YR 5670.00 6137.62 6142.96 6144.56 0.005565 10.13 559.68 121.63 0.83CL SAND CREEK 26328.81 200 YR 7054.00 6137.62 6143.59 6143.06 6145.49 0.005826 11.06 637.79 125.62 0.86CL SAND CREEK 26328.81 500 YR 9200.00 6137.62 6144.47 6144.04 6146.81 0.006112 12.26 750.57 131.16 0.90












CL SAND CREEK 25337.9* 1 YR 870.00 6133.43 6135.76 6136.10 0.004410 4.67 186.32 109.90 0.63CL SAND CREEK 25337.9* 1.5 YR 1280.00 6133.43 6136.22 6136.67 0.004577 5.35 239.08 118.06 0.66CL SAND CREEK 25337.9* 2 YR 1430.00 6133.43 6136.36 6136.85 0.004673 5.58 256.09 120.57 0.68CL SAND CREEK 25337.9* 10 YR 1890.00 6133.43 6136.75 6137.35 0.004968 6.22 303.86 127.38 0.71CL SAND CREEK 25337.9* 50 YR 4230.00 6133.43 6138.19 6137.67 6139.28 0.005741 8.37 505.59 151.29 0.81CL SAND CREEK 25337.9* 100 YR 5670.00 6133.43 6138.92 6138.37 6140.22 0.005638 9.16 618.72 159.23 0.82CL SAND CREEK 25337.9* 200 YR 7054.00 6133.43 6139.51 6138.97 6141.02 0.005650 9.88 714.12 167.78 0.84CL SAND CREEK 25337.9* 500 YR 9200.00 6133.43 6140.36 6139.79 6142.13 0.005482 10.69 870.13 196.36 0.84















CL SAND CREEK 25248.2* 1 YR 870.00 6128.28 6131.22 6131.48 0.002399 4.08 213.48 97.57 0.49CL SAND CREEK 25248.2* 1.5 YR 1280.00 6128.28 6131.71 6132.08 0.002861 4.86 263.51 105.60 0.54CL SAND CREEK 25248.2* 2 YR 1430.00 6128.28 6131.87 6132.28 0.003025 5.09 280.77 109.27 0.56CL SAND CREEK 25248.2* 10 YR 1890.00 6128.28 6132.31 6132.82 0.003349 5.72 330.24 116.42 0.60CL SAND CREEK 25248.2* 50 YR 4230.00 6128.28 6134.03 6134.96 0.003798 7.78 543.99 132.74 0.68CL SAND CREEK 25248.2* 100 YR 5670.00 6128.28 6134.81 6135.99 0.003998 8.72 650.14 138.63 0.71CL SAND CREEK 25248.2* 200 YR 7054.00 6128.28 6135.50 6136.88 0.004086 9.43 748.27 144.21 0.73CL SAND CREEK 25248.2* 500 YR 9200.00 6128.28 6136.46 6135.29 6138.12 0.004174 10.33 890.78 151.96 0.75









CL SAND CREEK 24840.8 1 YR 870.00 6126.72 6128.60 6128.94 0.004296 4.66 186.87 108.40 0.62CL SAND CREEK 24840.8 1.5 YR 1280.00 6126.72 6129.06 6129.51 0.004453 5.40 236.89 112.82 0.66CL SAND CREEK 24840.8 2 YR 1430.00 6126.72 6129.20 6129.70 0.004506 5.64 253.57 114.25 0.67CL SAND CREEK 24840.8 10 YR 1890.00 6126.72 6129.62 6130.23 0.004633 6.27 301.49 118.26 0.69CL SAND CREEK 24840.8 50 YR 4230.00 6126.72 6131.21 6132.31 0.004998 8.44 501.28 133.00 0.77CL SAND CREEK 24840.8 100 YR 5670.00 6126.72 6131.98 6133.33 0.005105 9.35 606.57 140.14 0.79CL SAND CREEK 24840.8 200 YR 7054.00 6126.72 6132.62 6134.20 0.005236 10.10 698.11 146.17 0.81CL SAND CREEK 24840.8 500 YR 9200.00 6126.72 6133.50 6132.81 6135.40 0.005377 11.06 831.80 155.03 0.84






CL SAND CREEK 24717.2* 1 YR 870.00 6126.21 6128.02 6128.35 0.004755 4.66 186.77 116.99 0.65CL SAND CREEK 24717.2* 1.5 YR 1280.00 6126.21 6128.42 6128.88 0.005123 5.45 234.91 122.93 0.69CL SAND CREEK 24717.2* 2 YR 1430.00 6126.21 6128.55 6129.05 0.005248 5.70 250.82 124.85 0.71CL SAND CREEK 24717.2* 10 YR 1890.00 6126.21 6128.91 6129.54 0.005502 6.36 296.96 129.80 0.74CL SAND CREEK 24717.2* 50 YR 4230.00 6126.21 6130.29 6131.47 0.006069 8.72 485.29 142.19 0.83CL SAND CREEK 24717.2* 100 YR 5670.00 6126.21 6130.94 6130.56 6132.43 0.006353 9.78 579.90 147.88 0.87CL SAND CREEK 24717.2* 200 YR 7054.00 6126.21 6131.56 6131.17 6133.27 0.006308 10.50 672.07 153.18 0.88CL SAND CREEK 24717.2* 500 YR 9200.00 6126.21 6132.32 6132.00 6134.42 0.006567 11.61 792.24 159.77 0.92
















CL SAND CREEK 24616.1* 1 YR 870.00 6121.18 6123.18 6123.74 0.007924 6.00 144.90 90.84 0.84CL SAND CREEK 24616.1* 1.5 YR 1280.00 6121.18 6123.55 6123.44 6124.34 0.009300 7.14 179.35 97.79 0.93CL SAND CREEK 24616.1* 2 YR 1430.00 6121.18 6123.66 6123.58 6124.53 0.009702 7.49 190.99 100.03 0.95CL SAND CREEK 24616.1* 10 YR 1890.00 6121.18 6124.01 6124.01 6125.09 0.010437 8.34 226.61 106.60 1.01CL SAND CREEK 24616.1* 50 YR 4230.00 6121.18 6125.59 6125.59 6127.22 0.008957 10.24 412.99 127.05 1.00CL SAND CREEK 24616.1* 100 YR 5670.00 6121.18 6126.32 6126.32 6128.26 0.008589 11.17 507.60 132.71 1.01CL SAND CREEK 24616.1* 200 YR 7054.00 6121.18 6126.97 6126.97 6129.15 0.008251 11.86 594.79 137.79 1.01CL SAND CREEK 24616.1* 500 YR 9200.00 6121.18 6127.87 6127.87 6130.39 0.007885 12.74 721.96 144.99 1.01








CL SAND CREEK 24501.27 1 YR 870.00 6113.20 6115.18 6115.06 6115.78 0.009044 6.18 140.76 93.43 0.89CL SAND CREEK 24501.27 1.5 YR 1280.00 6113.20 6115.99 6116.52 0.004973 5.83 219.53 101.40 0.70CL SAND CREEK 24501.27 2 YR 1430.00 6113.20 6116.28 6116.79 0.004242 5.75 248.84 104.21 0.66CL SAND CREEK 24501.27 10 YR 1890.00 6113.20 6116.91 6117.46 0.003596 5.97 316.49 110.42 0.62CL SAND CREEK 24501.27 50 YR 4230.00 6113.20 6118.98 6119.86 0.003023 7.54 564.34 127.55 0.62CL SAND CREEK 24501.27 100 YR 5670.00 6113.20 6120.08 6121.10 0.002652 8.14 708.88 135.33 0.60CL SAND CREEK 24501.27 200 YR 7054.00 6113.20 6121.04 6122.19 0.002423 8.62 842.40 142.14 0.59CL SAND CREEK 24501.27 500 YR 9200.00 6113.20 6122.39 6123.71 0.002194 9.27 1040.76 151.70 0.58






0 50 100 150 200 250 3006185

6190

6195

6200

6205

6210

6215

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 28377.18 Regulatory section AJ

Station (ft)

Elev

atio

n (ft

)

Legend

EG 100 YR - ex-bridge

EG 100 YR - Proposed

WS 100 YR - Proposed

WS 100 YR - ex-bridge

Ground

Bank Sta

.08 .03 .08

0 50 100 150 200 250 300 3506185

6190

6195

6200

6205

6210

6215

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 28261.16

Station (ft)

Elev

atio

n (ft

)

Legend



Crit 100 YR - ex-bridge



Crit 100 YR - Proposed

Ground

Bank Sta

.08 .03 .08

0 50 100 150 200 250 300 3506188

6190

6192

6194

6196

6198

6200

6202

6204


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.08 .03 .08

0 100 200 300 4006186

6188

6190

6192

6194

6196

6198

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 27907.71 top of drop structure

Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.04 .03 .03 .04

0 100 200 300 400 500 6006180

6185

6190

6195

6200

6205

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 27866.22 toe of drop structure

Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Ineff

Bank Sta

.012

.04 .03

.03

.067 .03

0 100 200 300 400 500 6006180

6185

6190

6195

6200

6205

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 27789.04 space center drive to station 100, detention pond to station 275

Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Ineff

Bank Sta

.03

.016

.012

.016 .04

.03 .04

.03

.03 .04

0 100 200 300 400 5006180

6185

6190

6195

6200

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 27636.91 space center drive to station 75, detention pond to station 100

Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Ineff

Bank Sta

.016 .06

.016

.04

.03 .03

.03 .04

0 100 200 300 400 500 6006180

6182

6184

6186

6188

6190

6192

6194

6196

6198

6200


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Ineff

Bank Sta

.04

.016

.04

.016

.04 .03 .03 .03 .04 .03

0 100 200 300 400 500 6006175

6180

6185

6190

6195

6200

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 27554.18 toe of drop.

Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Ineff

Bank Sta

.03 .016

.016

.016

.03 .03

.067 .03 .04 .03

0 100 200 300 400 500 6006175

6180

6185

6190

6195

6200

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 27512.09 Space Center drive sta 33 to 75 (asphalt with raised concrete me

Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Ineff

Bank Sta

.03 .016

.012

.016

.03 .03 .03

.067 .04 .03

0 50 100 150 200 250 300 3506174

6176

6178

6180

6182

6184

6186

6188

6190

6192

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 27380 upstream of Platte Ave Bridge xsec

Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Ineff

Bank Sta

.03

.03 .03

0 50 100 150 200 250 300 350 4006174

6176

6178

6180

6182

6184

6186

6188

6190

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 27300 BR

Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Ineff

Bank Sta

.03

.018

.04

.03 .04 .03

0 100 200 300 400 5006174

6176

6178

6180

6182

6184

6186

6188

6190

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 27300 BR

Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Ineff

Bank Sta

.03 .018

.04

.03 .04 .03

0 100 200 300 400 5006174

6176

6178

6180

6182

6184

6186

6188

6190


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Ineff

Bank Sta

.03 .03 .03

0 100 200 300 400 5006174

6176

6178

6180

6182

6184

6186

6188

6190


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Ineff

Bank Sta

.03 .03 .03

0 100 200 300 400 5006174

6176

6178

6180

6182

6184

6186

6188

6190

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 27147.73 CREST OF UPSTREAM DROP

Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 5006165

6170

6175

6180

6185

6190

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 27103.85 TOE OF UPSTREAM DROP

Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006165

6170

6175

6180

6185

6190


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006165

6170

6175

6180

6185

6190

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 27005.2*

Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006165

6170

6175

6180

6185

6190


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006165

6170

6175

6180

6185

6190


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006165

6170

6175

6180

6185

6190


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006165

6170

6175

6180

6185

6190

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 26965.48 APPROACH PROPOSED DROP E

Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006165

6170

6175

6180

6185

6190


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006165

6170

6175

6180

6185

6190


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006165

6170

6175

6180

6185

6190


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006165

6170

6175

6180

6185

6190

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 26960.21 CREST PROPOSED DROP E

Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006160

6165

6170

6175

6180

6185

6190


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006160

6165

6170

6175

6180

6185

6190


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006155

6160

6165

6170

6175

6180

6185

6190


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006155

6160

6165

6170

6175

6180

6185

6190

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 26920.21 TOE PROPOSED DROP E

Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006155

6160

6165

6170

6175

6180

6185

6190

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 26895.15 END SILL PROPOSED DROP E

Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006155

6160

6165

6170

6175

6180

6185


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006155

6160

6165

6170

6175

6180

6185


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006155

6160

6165

6170

6175

6180

6185


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006155

6160

6165

6170

6175

6180

6185


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006155

6160

6165

6170

6175

6180

6185


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006155

6160

6165

6170

6175

6180

6185


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006155

6160

6165

6170

6175

6180

6185


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006150

6155

6160

6165

6170

6175

6180

6185


Station (ft)

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)

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Ground

Bank Sta

.03 .03 .03

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6155

6160

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6185


Station (ft)

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)

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Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006150

6155

6160

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Station (ft)

Elev

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)

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Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006150

6155

6160

6165

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6175

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6185

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 26700.43 APPROACH PROPOSED DROP D

Station (ft)

Elev

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)

Legend





Ground

Bank Sta

.03 .067 .03

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6155

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Station (ft)

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Ground

Bank Sta

.03 .067 .03

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6155

6160

6165

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6185


Station (ft)

Elev

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)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006150

6155

6160

6165

6170

6175

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6185


Station (ft)

Elev

atio

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)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006150

6155

6160

6165

6170

6175

6180

6185

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 26695.2 CREST PROPOSED DROP D

Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006150

6155

6160

6165

6170

6175

6180

6185


Station (ft)

Elev

atio

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)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006145

6150

6155

6160

6165

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6175

6180

6185


Station (ft)

Elev

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)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006145

6150

6155

6160

6165

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6175

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Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006140

6145

6150

6155

6160

6165

6170

6175

6180

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 26655.21 TOE PROPOSED DROP D

Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .067 .03

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6145

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Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 26624.77 END SILL PROPOSED DROP D

Station (ft)

Elev

atio

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)

Legend





Ground

Bank Sta

.03 .067 .03

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6145

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Station (ft)

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Ground

Bank Sta

.03 .03 .03

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6145

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Station (ft)

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Ground

Bank Sta

.03 .03 .03

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6145

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Station (ft)

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Ground

Bank Sta

.03 .03 .03

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6145

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Station (ft)

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Ground

Bank Sta

.03 .03 .03

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6145

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Station (ft)

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)

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Ground

Bank Sta

.03 .03 .03

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6145

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Station (ft)

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Ground

Bank Sta

.03 .03 .03

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6145

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Station (ft)

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Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 5006140

6145

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6155

6160

6165

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Station (ft)

Elev

atio

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)

Legend







Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 5006140

6145

6150

6155

6160

6165

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6175

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Station (ft)

Elev

atio

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)

Legend







Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 5006140

6145

6150

6155

6160

6165

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6175

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Station (ft)

Elev

atio

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)

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Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 5006140

6145

6150

6155

6160

6165

6170

6175

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Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 26435.64 APPROACH PROPOSED DROP C

Station (ft)

Elev

atio

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)

Legend





Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 5006140

6145

6150

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Station (ft)

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atio

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)

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Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 5006140

6145

6150

6155

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6175

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Station (ft)

Elev

atio

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)

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Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 5006140

6145

6150

6155

6160

6165

6170

6175

6180


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 5006140

6145

6150

6155

6160

6165

6170

6175

6180

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 26430.65 CREST PROPOSED DROP C

Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 5006140

6145

6150

6155

6160

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6175

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Station (ft)

Elev

atio

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)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 5006140

6145

6150

6155

6160

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6175

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Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 5006130

6140

6150

6160

6170

6180


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 5006130

6140

6150

6160

6170

6180

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 26406.75 TOE PROPOSED DROP C

Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 5006130

6140

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Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 26381.6 END SILL PROPOSED DROP C

Station (ft)

Elev

atio

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)

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Ground

Bank Sta

.03 .067 .03

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6140

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Station (ft)

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Ground

Bank Sta

.03 .03 .03

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6140

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Station (ft)

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Ground

Bank Sta

.03 .03 .03

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6140

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Station (ft)

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)

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Ground

Bank Sta

.03 .03 .03

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6140

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Station (ft)

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)

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Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 5006130

6140

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Station (ft)

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atio

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)

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Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 5006135

6140

6145

6150

6155

6160

6165

6170

6175


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006135

6140

6145

6150

6155

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6170


Station (ft)

Elev

atio

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)

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Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006135

6140

6145

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Station (ft)

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atio

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)

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Ground

Bank Sta

.03 .03 .03

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6140

6145

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Station (ft)

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atio

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)

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Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006130

6135

6140

6145

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Station (ft)

Elev

atio

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)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006130

6135

6140

6145

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6165


Station (ft)

Elev

atio

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)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006130

6135

6140

6145

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6155

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Station (ft)

Elev

atio

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)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006130

6135

6140

6145

6150

6155

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6165


Station (ft)

Elev

atio

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)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006130

6135

6140

6145

6150

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6165


Station (ft)

Elev

atio

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)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006130

6135

6140

6145

6150

6155

6160


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006130

6135

6140

6145

6150

6155

6160


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006130

6135

6140

6145

6150

6155

6160


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006130

6135

6140

6145

6150

6155

6160

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 25308.5 APPROACH PROPOSED DROP B

Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006130

6135

6140

6145

6150

6155

6160


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006130

6135

6140

6145

6150

6155

6160


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006130

6135

6140

6145

6150

6155

6160


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006130

6135

6140

6145

6150

6155

6160

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 25303.18 CREST PROPOSED DROP B

Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006130

6135

6140

6145

6150

6155

6160


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006130

6135

6140

6145

6150

6155

6160


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006125

6130

6135

6140

6145

6150

6155

6160


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006125

6130

6135

6140

6145

6150

6155

6160

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 25283.18 TOE PROPOSED DROP B

Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006125

6130

6135

6140

6145

6150

6155

6160

6165

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 25258.2 END SILL

Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .067 .03

0 100 200 300 400 500 6006125

6130

6135

6140

6145

6150

6155

6160

6165


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006125

6130

6135

6140

6145

6150

6155

6160

6165


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006125

6130

6135

6140

6145

6150

6155

6160

6165


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006125

6130

6135

6140

6145

6150

6155

6160

6165


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006125

6130

6135

6140

6145

6150

6155

6160

6165


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006125

6130

6135

6140

6145

6150

6155

6160

6165


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 100 200 300 400 500 6006125

6130

6135

6140

6145

6150

6155

6160


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 50 100 150 200 250 300 3506125

6130

6135

6140

6145


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 50 100 150 200 2506126

6128

6130

6132

6134

6136

6138

6140


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .03 .03

0 50 100 150 200 2506126

6128

6130

6132

6134

6136

6138


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .03 .03

0 50 100 150 200 2506126

6128

6130

6132

6134

6136

6138


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .03 .03

0 50 100 150 200 2506126

6128

6130

6132

6134

6136

6138


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .03 .03

0 50 100 150 200 2506126

6128

6130

6132

6134

6136

6138


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 50 100 150 200 2506126

6128

6130

6132

6134

6136

6138

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 24697.27 APPROACH PROPOSED DROP A

Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03

.067 .03

0 50 100 150 200 2506126

6128

6130

6132

6134

6136

6138


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03

.067 .03

0 50 100 150 200 2506126

6128

6130

6132

6134

6136

6138


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03

.067 .03

0 50 100 150 200 2506126

6128

6130

6132

6134

6136

6138


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03

.067 .03

0 50 100 150 200 2506126

6128

6130

6132

6134

6136

6138

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 24691.98 CREST PROPOSED DROP A

Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03

.067 .03

0 50 100 150 200 2506124

6126

6128

6130

6132

6134

6136

6138


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03

.067 .03

0 50 100 150 200 2506122

6124

6126

6128

6130

6132

6134

6136

6138


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03

.067 .03

0 50 100 150 200 2506122

6124

6126

6128

6130

6132

6134

6136

6138


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03

.067 .03

0 50 100 150 200 2506120

6122

6124

6126

6128

6130

6132

6134

6136

6138

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 24673.7 TOE PROPOSED DROP A

Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03

.067 .03

0 50 100 150 200 2506120

6122

6124

6126

6128

6130

6132

6134

6136

6138

6140

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 24646.08 END SILL PROPOSED DROP A

Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .067 .03

0 50 100 150 200 2506120

6122

6124

6126

6128

6130

6132

6134

6136

6138

6140


Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.03 .03 .03

0 50 100 150 200 2506120

6125

6130

6135

6140


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .03 .03

0 50 100 150 200 250 3006120

6125

6130

6135

6140


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .03 .03

0 50 100 150 200 250 3006120

6125

6130

6135

6140


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .03 .03

0 50 100 150 200 250 3006120

6125

6130

6135

6140


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.03 .03 .03

50 100 150 200 250 300 350 4006120

6125

6130

6135

6140

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 24540.39 CREST OF DOWNSTREAM DROP STRUCTURE

Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.045 .03 .045

50 100 150 200 250 300 350 4006115

6120

6125

6130

6135

6140

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 24526.15 WEST FORK MODEL SECTION 380.96

Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.045 .03 .045

50 100 150 200 250 300 350 4006115

6120

6125

6130

6135

6140

6145


Station (ft)

Elev

atio

n (ft

)

Legend







Ground

Bank Sta

.045 .03 .045

0 50 100 150 200 250 300 350 4006110

6115

6120

6125

6130

6135

6140

Sand Creek at Platte Ave Plan: 1) ex-bridge 3/26/2018 2) Proposed 4/24/2018 RS = 24501.27 TOE OF DOWNSTREAM DROP STRUCTURE

Station (ft)

Elev

atio

n (ft

)

Legend





Ground

Bank Sta

.045 .03 .045

150 200 250 300 350 4006112

6114

6116

6118

6120

6122

6124

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.045 .025 .045

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)

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.045 .025 .045

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6115

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)

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.045 .025 .045

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.045 .025 .045

0 100 200 300 400 5006110

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A-2

APPENDIX B - CALCULATIONS

/ SCOUR

/ Riprap

RESPEC

Technical MEMORANDUM

From: Josh Morin, PE, CFM

Date: April 23, 2018

Subject: Platte Avenue over Sand Creek – 60% Design Scour Results

The purpose of this memo is to document the scour results for the 60% design of the proposed bridge replacement of Platte Avenue over Sand Creek. This memo details the estimated scour depths during the 100-year, 200-year, and 500-year flood events for the 60% design bridge configuration. The following sections describe the scour calculation methodology and the results for abutment, contraction, and pier scour.

SCOUR CALCULATION METHODOLOGY

Scour Calculation Criteria Hydraulic Engineering Circular No. 18 (HEC-18): Evaluating Scour at Bridges (5th Edition, 2012), which was developed by the Federal Highway Administration (FHWA), was utilized to calculate the predicted scour depths. Specifically, Chapter 6 – Contraction Scour, Chapter 7 – Pier Scour, and Chapter 8 – Evaluating Local Scour at Abutments, were referenced to predict local and general scour. The 100-year, 200-year, and 500-year flood events were analyzed for scour risk. The 60% desgin bridge configuration was modeled for the scour analysis: a three-span configuration with 4-feet wide piers. Site visits show that the Sand Creek channel bed is comprised primarily of sand. Based on these conditions, the sediment particle size was approximated as 0.25 mm for d50 and 0.5 mm for d95. The gradation analysis from the forthcoming geotechnical study will be used for the final scour analysis, but based on the sandy bed condition, it is not anticipated that the addition of the gradation analysis’ d50

and d95 values will have a significant impact on the scour calculations shown below.

Contraction Scour Contraction scour occurs when the floodplain upstream of a bridge is forced to constrict to pass through bridge, causing increases in velocity and stream power that have the potential to erode the stream bed through the bridge. Contraction scour is considered as a general scour that will uniformly erode the stream bed as opposed to only at a localized point, such as pier and abutment scour. HEC-18 provides the live-bed and clear water scour equations. Based on the particle size present in Sand Creek, the live-bed scour equation was used to estimate the contraction scour depth. The parameters used in the contraction scour equations were determined from the survey data and from simulating the flood events in the HEC-RAS model. Cross section 27512.09 was chosen as the approach channel section. This section accurately represents the general channel geometry upstream of the bridge and was compared to the bridge cross section to determine the magnitude of the contraction scour. The bridge opening width for the 60% design configuration was used for the

Platte Avenue Over Sand Creek // 2 April 23, 2018

RESPEC

contracted channel widths. The flow area and channel flows were determined from the HEC-RAS flow distribution results for each cross section.

Pier Scour Pier scour occurs when flow depths and velocities directly upstream of the piers are great enough to create eddies which erode the area around the piers. Pier scour is localized to the piers. The CSU pier scour equation was used to calculate the depth of the scour at the piers. The parameters used in the pier scour equations were determined from the 60% design bridge geometry and by simulating the flood events in the HEC-RAS model. The flow depth directly upstream of the bridge and the maximum velocity through the bridge, as determined by the model, were used. Based on the bridge and sediment characteristics, the appropriate values were chosen for the K1, K2, and K3 correction factors.

Abutment Scour Similar to contraction scour, abutment scour occurs when the floodplain upstream of the bridge constricts to pass through the bridge. Due to the cross flows parallel and perpendicular to the abutments, localized scour can develop at the upstream and downstream ends of the bridge at the abutments. The NCHRP method was utilized to calculate the estimated scour at the abutments. The parameters used in the abutment scour equation were determined from the HEC-RAS flow distribution results from cross sections at the bridge and upstream of the bridge.

SCOUR RESULTS The following table summarizes the results from the scour analysis. As the table shows, the only significant scour predicted to occur during the 100-year, 200-year, 500-year events is pier scour. The bridge, as configured, is well-aligned to the upstream flow of Sand Creek and the 100-year, 200-year, 500-year floodplains do not significantly constrict to pass through the bridge. This configuration mitigates the factors that typically cause appreciable contraction and abutment scour.

Flood Event Bridge Configuration Contraction Scour (ft) Pier Scour (ft) Left Abutment

Scour (ft) Right Abutment

Scour (ft)

100-Year Three-Span, 4’ Piers 0.0 8.0 0.0 1.0



*Detailed scour results are attached to this memorandum

PROJECT: Platte Ave over Sand Creek - 3-SpanDATE: 23-Apr-18EVENT: 100-Year

Left Right100-Year 5,670 cfs 6180.37' 8.0 0.0 0.0 0.0 1.0

NCHRP Abutment Scour = 0.0' 1.0'

Scour Summary

Scour Summary

Event DischargeContraction

Scour

Abutment

WSEL

Long Term Aggradation / Degradation

PierScour


PIER SCOURCSU Equation For both Live bed and Clear water scour

Description Sourcey1= 5.08 Flow depth directly upstream of pier in ft Max Y1 from HEC-RASK1= 1 Correction factor for pier nose shape Table 7-1 Group of Cylinders= 0 Angle of attack of the flow Site topo - bridge well-aligned

K2= 1 Correction factor for angle of attack of flow from Eq. 7.4K3= 1.1 Correction factor for bed condition from Table 7-3 Assumed no dunes (typical of Colorado)

a= 4.00 Pier width, (ft) Bridge plansL= Pier length (ft) Group of Cylinders

Fr1= 0.65912 Froude number directly upstream of the pier (calculated)V1= 8.43 Mean Velocity of flow directly upstream of pier (ft/s) Max velocity at River Station 27380

D50= 0.25 Particle Size in mm Assumed sand 1/4 mmD95= 0.5 Particle Size in mm Assumed sand 1/2 mm

K4 1 If D50<2 mm or D95<20 mm, then K4 = 1If D50>2 mm or D95>20 mm, then K4 = 0.4(Vr)^0.15Basically K4 is between 0.4 (min value) and 1, 1 probably is the most conservative.

Ys= 8.00 Scour depth (ft)

Variable

43.01

65.0

14321

1

0.2 FryaKKKK

yys

Z:\City of Colorado Springs\03177_Platte Ave Over Sand Creek\EXCEL\Design Calculations\Scour Analysis\Scour Worksheet Platte Ave - 3-span - 100-Year - 4-19-18Pier Scour


CONTRACTION SCOURLive Bed Transport of bed material in the upstream reach into the bridge cross section (HIGH VELOCITIES AND SMALL BED MATERIAL WILL CREATE LIVE BED SCOUR)

VARIABLE Description SourceA1= 648.55 Flow area of the stream main channel (ft2) Main channel flow area XS 27512.09 (RAS)A2= 781.15 Flow area of the contracted section (ft2) Bridge opening area (RAS)y1= 5.24 Average depth in the stream main channel, (ft) A1/W1yo= 4.58 Average depth in the contracted section, (ft) A2/W2

Q1= 5669.99 Flow in the upstream channel transporting sediment, (cfs) Main channel flow XS 27512.09 (RAS)Q2= 5670.00 Flow in the contracted channel, (cfs) Flow in channel at bridge (RAS)W1= 123.8 Bottom/top width of the upstream main channel, (ft) Main channel width XS 27512.09 (RAS)W2= 170.67 Bottom/top width of the main channel in the contracted section minus Pier width, (ft) Bridge US section bottom deck widthS1= 0.010786 Slope of the energy grade line of the main channel (ft/ft) Average E.G. slope upstream of bridge

omega (w)= 0.065617 Find D50 then see figure (right) - Fall velocity (ft/s) Estimate from Site visit

V*= 1.35 Shear Velocity (ft/s)V*/omega(w)= 20.56

k1= 0.69 See Table 1y2= 4.20 Average Depth in the contracted section (scoured) (ft)

Contraction Scour= 0.00 Average Contraction Scour Depth (ft)

Clear-Water

VARIABLESyo= 4.58 Average depth in the contracted section,Q= 5670 Discharge through the bridge or on the setback overbank area at the bridge associated with the width WW= 170.67 Bottom or top width of the contracted section

D50= 0.00082021 Median diameter (ft) - Sieve AnalysisDm 0.0010 Diameter of the smallest non-transferable particle in the bed material (1.25 D50) in the contracted section (ft)Ku= 0.0077 Constant (English Units)y2= 17.84 Avg equilibrium depth in the contracted section after contraction scour (ft)


Vavg > Vc, Use Live Bed Scour Equation

1

2

17/6

1

2

1

2k

WW

QQ

yy

Z:\City of Colorado Springs\03177_Platte Ave Over Sand Creek\EXCEL\Design Calculations\Scour Analysis\Scour Worksheet Platte Ave - 3-span - 100-Year - 4-19-18Contraction Scour


ABUTMENT SCOURHEC-18 NCHRP 24-20 Abutment Scour Approach

Description Sourceq1= 45.80 Upstream unit discharge, ft2/s (m2/s) HEC Output Q/W

q2c= 33.2 Unit discharge in the constricted opening accounting for non-uniform flow distribution, ft2/s (m2/s) HEC Output Q/Wq2c/q1= 0.73 Ratio of upstream unit discharge to unit discharge in the constricted opening

Bed Conditions= If Live bed conditions leave blank, if clear-water conditions use "C"A or B= 1.20 Amplification factor for live-bed ( A) or clear-water ( B) conditions. From Figs. 8.9 through 8.12 Figures 8.9 through 8.12 (HEC-18)

y1= 5.24 Upstream flow depth, ft (m) HEC OutputKu= 11.17 11.17 English units, 6.19 SI units HEC-18

D50= 0.00082021 Particle size with 50 percent finer, ft (m) Grain size distributionyc= 3.98 Flow depth including clear-water contraction scour, ft (m)

ymax= 4.77 Maximum flow depth resulting from abutment scour, ft (m) HEC Outputy0(left)= 5.42 Flow depth at left abutment prior to scour, ft (m) HEC Output

y0(right)= 3.80 Flow depth at right abutment prior to scour, ft (m) HEC Output

ys (left)= 0.00 Left abutment scour depth, ft (m)ys (right)= 0.97 Right abutment scour depth, ft (m)

Variable

or




Scour Summary

Scour Summary


Scour

Abutment

WSEL


PierScour










Variable

43.01

65.0

14321

1

0.2 FryaKKKK

yys










Clear-Water





1

2

17/6

1

2

1

2k

WW

QQ

yy












Variable

or




Scour Summary

Scour Summary


Scour

Abutment

WSEL


PierScour










Variable

43.01

65.0

14321

1

0.2 FryaKKKK

yys










Clear-Water





1

2

17/6

1

2

1

2k

WW

QQ

yy












Variable

or

RRESPEC

From: Carrie Herbolsheimer, PE, CFM

Date: April 24, 2018

Subject: Platte Avenue over Sand Creek – 60% Design Riprap Abutment Protection Calculations

The purpose of this memo is to document the riprap abutment protection sizing for the 60% design of the proposed bridge replacement of Platte Avenue over Sand Creek. This memo details the estimated riprap size required to protect the bridge abutments during the 100-year, 200-year, and 500-year flood events for the 60% design bridge configuration. The following sections describe the riprap sizing calculation methodology and results.

Hydraulic Engineering Circular No. 23 (HEC-23): Bridge Scour and Stream Instability Coutnermeasures: Experience, Selection, and Design Guidance (3rd Edition, 2009), which was developed by the Federal Highway Administration (FHWA), was utilized as the first reference to calculate the recommended riprap abutment scour protection. The 100-year, 200-year, and 500-year flood events were analyzed for revetment sizing. The 60% design bridge configuration was modeled: a three-span configuration with 3-feet diameter piers, and no significant channel contraction or expansion through the bridge.

The Urban Drainage and Food Control District, Drainage Criteria Manual, Volume 2 (2017), specifically equation 8-11 was used as a check calculation because the conditions modeled Design Guideline 14 are not applicable to this project. The UDFCD equation is recommended for channel bank stabilization without expansion and contraction effects, which is more applicable to the bridge configuration at The E Platte Ave Bridge. The 100-year, 200-year, and 500-year flood events were analyzed for riprap sizing. The bridge and flow conditions were otherwise the same as those used for the Design Guideline 14 sizing.

The following table summarizes the results from the riprap sizing calculations. As the table shows, there is a significant difference in the recommended riprap size based on the two approaches. Because the bridge is configured such that there is no expansion or contraction through the bridge, the UDFCD channel riprap sizing methodology is a more appropriate approach for riprap sizing. Based upon engineering judgement and the urban nature of the project with the potential for vandalism, a minimum riprap D50 dimension of 18-inches is recommended for this project.

RRESPEC

Flood Event Design Guideline 14

D50 (in)

UDFCD Eqn 8-11

D50 (in)

Selected

D50 (in)

100-Year 27 6 18

200-Year 31 7 18

500-Year 37 8 18

*Detailed riprap sizing calculations are attached to this memorandum

Platte Ave Bridge over Sand CreekDesign Guideline 14 CalculationsBridge Abutment Riprap500-year Storm Event

Riprap SizingFr= 1.00 Channel Froude Number (from HEC RAS bridge output) - Used to select formulaL= 0.00 Abutment Length - used for SBR Calculationya= 1.00 Average Flow Depth in the Overbank (from scour calcs) - used for SBR CalculationSBR= 0.00 Setback Ratio - Used to select Q and AQ= 9200.00 Flow (cfs) - For SBR >5, Use Qe from abutment scour calcs; For SBR < 5 Use channel QA= 769.53 Flow Area (ft2) - For SBR > 5, Use Ae from abutment scour calcs; For SBR < 5 Use channel Areay= 5.19 Depth of flow in bridge openingSg= 2.50 Specific gravity of riprapg= 32.20 gravitational constantK= 0.89 Scaling Factor, see below

V= 11.96 Characteristic Average Velocity - See Belowd50= 3.01 feet

Use D50 of 36 inches Wrap protection 20 feet along upstream and downstream embankment and 20 feet into the channel









Sand Creek Channel Restoration Channel Slopes and Toe Protection Riprap Sizing, UDFCD DCM VOL 2 CHAPTER 8 (2016 ED)Date: 4/23/2018Calculations By: Carrie HerbolsheimerChecked By:

Use Section 2.6 Grouted Stepped Boulder Drop StructuresDetermine Rock Sizing Parameter

Equation 8-11

S 0.004 ft/ftGs 2.5Station 252+28.2 (max velocities in project reach outside of drops)V100 10.59 ft/sD50>= 0.496166 ft

6.0 inV500 11.96 ft/sD50>= 0.632845 ft

7.6 inV200 10.98 ft/sD50>= 0.533384 ft

6.4 in

Solve for max velocity by rock sizeVmaxTypeL 13.30 ft/sD50>= 0.783174 ft

9.4 in Type LVmaxTypeM 15.36 ft/sD50>= 1.044233 ft

12.5 in Type MVmaxTypeH 18.82 ft/sD50>= 1.6 ft

18.8 in Type H


A-3

APPENDIX C - WORK MAPS FOR EXISTING AND PROPOSED CONDITIONS

269+

00

270+

0027

1+00

272+

0027

3+00

274+

0027

5+00

276+

0027

7+00

271+66.94

271+93.38

272+53.69

273+27.15

273+80.00

275+12.09

275+54.18

275+97.33

276+36.91

AIAPPROX BRIDGEFOOTPRINT

EX FLOODPLAIN

Feet0 20 40

Documents

EAST PLATTE AVENUE BRIDGE REPLACEMENT OVER SAND CREEK · respec.com final channel design report east platte avenue bridge replacement over sand creek contract t008594 prepared for