HYDRAULIC EVALUATION
OF LEVEE REPAIR TECHNIQUES
A Project
Presented to the faculty of the Department of Civil Engineering
California State University, Sacramento
Submitted in partial satisfaction of
the requirements for the degree of
MASTER OF SCIENCE
in
Civil Engineering
by
Syada Iffat Ara
SPRING
2012
© 2012
Syada Iffat Ara
ALL RIGHTS RESERVED
ii
HYDRAULIC EVALUATION
OF LEVEE REPAIR TECHNIQUES
A Project
by
Syada Iffat Ara
Approved by:
__________________________________, Committee Chair
Saad Merayyan, Ph.D.
____________________________
Date
_______________________________, Second Reader
Kevin Flora, P.E.
__________________________
Date
iii
Student: Syada Iffat Ara
I certify that this student has met the requirements for format contained in the University format
manual, and that this Project is suitable for shelving in the Library and credit is to be awarded for
the Project.
__________________________, Graduate Coordinator
Cyrus Aryani, Ph.D., P.E., G.E.
Department of Civil Engineering
iv
___________________
Date
Abstract
of
HYDRAULIC EVALUATION
OF LEVEE REPAIR TECHNIQUES
by
Syada Iffat Ara
This project presented the techniques of levee erosion repair and their hydraulic
evaluation. For the project purpose a site located at San Joaquin River at River Mile 71.5,
Right Bank (SJR RM 71.5R) has been selected. The site is located at as outside bend of a
tight meander and is subjected to severe erosion. In this study, a simulation model using
HEC-RAS hydraulic model has been performed to determine the existing hydraulic
characteristics for the project design flow and 100-year flow and another simulation
model has been performed to determine the impact of the repair to the existing system.
The design of the erosion site involved alternative analysis and selection of most
appropriate repair alternative, determining site existing hydraulic characteristics,
determining repair cross-section using hydraulic characteristics, and evaluating impact of
the repair on existing system. For alternative analysis, four alternatives have been
considered and analyzed, and most feasible alternative – waterside repair (rock slope
protection) has been selected as a repair option. Hydraulic characteristics of the River
have been determined by using HEC-RAS hydraulic model. Using hydraulic
characteristics and physical parameters of the site, the minimum required rock size for the
v
site has been determined by using CHNL PRO software. The repair section for the
erosion site has been determined by D50 rock size.
As the repair is a waterside repair and is going to encroach into the available
conveyance area, a hydraulic analysis is required to evaluate the impact of the repair to
the existing system. Once the repair section of the site has been finalized, the impact of
the repair to existing system has been analyzed by using HEC-RAS hydraulic model. The
results of the analysis show that the repair has very little or insignificant impact on the
existing system. If there were any adverse impact on the existing system due to the
waterside repair, another alternative other than waterside repair would be considered as a
remedy of the erosion problem.
_______________________, Committee Chair
Saad Merayyan, Ph.D.
_______________________
Date
vi
ACKNOWLEDGEMENTS
I am heartily thankful to my advisor, Professor Saad Merayyan for allowing me to
pursue this work and for his support and guidance throughout the completion of the
project.
I would also like to thank Department of Water Resources (DWR) for letting me
use the data for the project.
Lastly, I offer my gratitude to my husband, Muhammad Waliullah for his support
and encouragement during the completion of the project. Finally and above all, Rohaan
and Liyana (my two little kids), this is all for you.
vii
TABLE OF CONTENTS
Page
Acknowledgements ................................................................................................................ vii
List of Tables ............................................................................................................................ x
List of Figures .......................................................................................................................... xi
Chapter
1. INTRODUCTION ……………. ……………………………………………………….. 1
1.1 Background ............................................................................................................ 1
1.2 Purpose .................................................................................................................. 2
2. GENERAL DESCRIPTION OF THE STUDY AREA ...................................................... 3
2.1 Location ................................................................................................................. 3
2.2 Levee Geometry and Erosion Description ............................................................. 4
3. ALTERNATIVE ANALYSIS ............................................................................................ 7
3.1 Introduction............................................................................................................ 7
3.2 Alternatives ............................................................................................................ 7
3.2.1 Alternative 1 - No Action ...................................................................... 7
3.2.2 Alternative 2 – Waterside Repair........................................................... 8
3.2.3 Alternative 3 – Setback Levee ............................................................. 12
3.2.4 Alternative 4 – Relief Channel ............................................................ 15
3.3 Recommended Alternative................................................................................... 19
4. DESIGN PARAMETERS FOR FEASIBLE ALTERNATIVE ....................................... 20
4.1 Data Gathering and Processing ............................................................................ 20
4.2 Hydraulic Analysis .............................................................................................. 21
4.2.1 Calibration of the Model ...................................................................... 25
4.2.2 Simulation Run .................................................................................... 28
4.3 Riprap Design ...................................................................................................... 32
4.3.1 Stone Shape.......................................................................................... 33
4.3.2 Stone Size and Weight ......................................................................... 33
4.3.3 Layer Thickness ................................................................................... 33
4.3.4 Side Slope Inclination .......................................................................... 34
viii
4.3.5 Channel Roughness, Shape, Alignment and Gradient ......................... 34
4.3.6 Selection of Rock Size ......................................................................... 34
4.3.7 Gradation of Riprap ............................................................................. 37
4.4 Repair Section Design.......................................................................................... 38
4.4.1 Launch Rock ........................................................................................ 39
4.4.2 Riparian Bench .................................................................................... 39
4.4.3 Rock Slope Protection ......................................................................... 39
5. EVALUATION OF REPAIR IMPACT ON EXISTING RIVER
HYDRAULICS ................................................................................................................. 46
5.1 Introduction.......................................................................................................... 46
5.2 Hydraulic Analysis .............................................................................................. 46
6. CONCLUSIONS AND RECOMMENDATIONS ........................................................... 56
6.1 Conclusions.......................................................................................................... 56
6.2 Recommendations ................................................................................................ 57
Appendix A Site Photographs .............................................................................................. 58
Appendix B CHANLPRO Program – Input and Output....................................................... 62
Appendix C CDEC Data – Summer Water Surface Elevation Calculation .......................... 65
Appendix D HEC-RAS Output ............................................................................................. 70
Appendix E Compact Disk (CD) – HEC-RAS Model .......................................................... 73
References ............................................................................................................................... 74
ix
LIST OF TABLES
Tables
Page
1.
Table 2.2.1 – Standard Levee Prism Geometry ..................................................... 5
2.
Table 3.2.2.1 – Soft Costs ...................................................................................... 10
3.
Table 3.2.2.2 – Design Estimate Considerations for Alternative 2 ................... 11
4.
Table 3.2.2.3 – Cost Estimate for Alternative 2.......................................................... 11
5.
Table 3.2.3.1 – Design Estimate Considerations for Alternative 3............................. 14
6.
Table 3.2.3.2 – Cost Estimate for Alternative 3.......................................................... 15
7.
Table 3.2.4.1 – Design Estimate Considerations for Alternative 4............................. 18
8.
Table 3.2.4.2 – Cost Estimate for Alternative 4.......................................................... 18
9.
Table 4.2.1.1 – Manning’s n-Value ............................................................................ 27
10.
Table 4.2.2.1 – HEC-RAS Output .............................................................................. 29
11.
Table 4.3.7.1 – Gradation Table ................................................................................. 38
12.
Table 5.2.1 – Manning’s n-Value for Post Repair Condition ..................................... 47
13.
Table 5.2.2 – Comparison of WSE and V for Existing Condition and Post
Repair Condition ......................................................................................................... 52
x
LIST OF FIGURES
Figures
Page
1.
Figure 2.1 Location Map of SJR RM 71.5R........................................................... 3
2.
Figure 2.2 Vicinity Map of SJR RM 71.5R ............................................................ 4
3.
Figure 2.3 Erosion Progression at SJR RM 71.5R ................................................ 6
4.
Figure 3.2.2.1 Alternative 2 Repair Footprint ........................................................ 9
5.
Figure 3.2.2.2 Typical Repair Section ................................................................... 10
6.
Figure 3.2.3.1 Alternative 3 Repair Footprint ...................................................... 13
7.
Figure 3.2.3.2 Typical Repair Section ................................................................... 14
8.
Figure 3.2.4.1 Alternative 4 Repair Footprint ....................................................... 17
9.
Figure 3.2.4.2 Typical Cross-Section .................................................................... 18
10.
Figure 4.2.1 Presentation of Terms in the Energy Equation (Gary W.
Brunner, 2010) .......................................................................................................... 22
11.
Figure 4.2.2 HEC-RAS Conveyance Subdivision Method (Gary W.
Brunner, 2010) .......................................................................................................... 24
12.
Figure 4.2.1.1 HEC-RAS Channel Alignment ..................................................... 26
13.
Figure 4.2.1.2 Location of VNS Gauging Station ............................................... 27
14.
Figure 4.4.1 Typical Cross-Section ....................................................................... 41
15.
Figure 4.4.2 Repair Footprint – Plan 1 of 3 .......................................................... 42
16.
Figure 4.4.3 Repair Footprint – Plan 2 of 3 .......................................................... 43
17.
Figure 4.4.4 Repair Footprint – Plan 3 of 3 .......................................................... 44
xi
18.
Figure 4.4.5 Full Repair Footprint ......................................................................... 45
19.
Figure 5.2.1 – Cross-Section with Repair on Existing System with 100-Year
Water Surface Elevation (From River Station 71.59 to 71.486) ................................. 49
20.
Figure 5.2.2 – Water Surface Profile for 100-Year and Design Flow for Existing
and Post Project Condition.......................................................................................... 50
21.
Figure 5.2.3 – Velocity Profile for 100-Year and Design Flow for Existing and
Post Project Condition ................................................................................................ 51
22.
Figure D.1 – Cross-Section with Repair on Existing System with 100-Year
Water Surface Elevation (From River Station 71.66 to 71.625) ................................. 71
23.
Figure D.2 – Cross-Section with Repair on Existing System with 100-Year Water
Surface Elevation (From River Station 71.451 to 71.35) ........................................... 72
xii
1
Chapter 1
INTRODUCTION
1.1 Background
The purpose of this project is to repair erosion site at the right bank of the San
Joaquin River, River Mile 71.5R (SJR RM 71.5R). The SJR RM 71.5R is located in
Reclamation District 2064 (RD 2064). RD 2064 is located in San Joaquin County and
includes approximately 11.5 miles of levee along the right banks of San Joaquin and
Stanislaus Rivers. Levees along the San Joaquin and Stanislaus Rivers provide direct
protection to adjacent agricultural land within Reclamation District No. 2064.
A levee can be defined as an earthen embankment which protects a region of
floodplain from the floodwaters of a river. A levee offers complete protection until either
the embankment fails or is overtopped. Levees are the primary method of flood
protection along many rivers where floodplains are used primarily for agriculture or are
inhabited. An erosion site is defined as a site that is at risk of failure by erosive forces
during floods and/or normal flow condition. This study, involved analyzing alternatives
to determine the most feasible solution to address the problem, determining hydraulic
characteristics of the existing system, designing the most feasible alternative for the
erosion site using hydraulic parameters, and finally finding impact of the repair on water
surface elevation and velocity of the existing river system. In order to determine the most
suitable gradation of the rock material to be used in repair application software called
CHANLPRO has been used, and the HEC-RAS has been used to define the hydraulic
2
parameters of the river’s existing condition and to evaluate the impact of repair to the
system.
1.2 Purpose
The purpose of this study is to determine the most appropriate scour
countermeasure and its impact to existing river hydraulics. This study will provide the
procedures to be followed in erosion repair and will assess the impact of the erosion
repair on the hydraulic performance of the existing system. Based on the levee repair
technique, the objective of this study has been group into three different phases.
Phase 1:

Alternative analysis
Phase 2:

Design parameters for feasible alternative
Phase 3:

Evaluate hydraulic impact of the selected alternative to the existing system
Chapter 2
3
GENERAL DESCRIPTION OF STUDY AREA
2.1 Location
The project site is located along the right bank of the San Joaquin River; about 8
miles southwest of Ripon and 9 miles south of Lathrop, in San Joaquin County,
California. The site can be accessed via a County Road off of South Airport Way, 200
feet south of the intersection with Division Road. See Figure 2.1 – location map of the
SJR RM 71.5R.
Figure 2.1 - Location Map of SJR RM 71.5R
4
The Reclamation District 2064 levees provide flood protection to the Durham
Ferry Educational Facility as well as to agricultural and rural residential uses in the
vicinity. See Figure 2.2 – vicinity map of the SJR RM 71.5R.
Figure 2.2 – Vicinity Map of SJR RM 71.5R
2.2 Levee Geometry and Erosion Description
The levee in the project area is generally 10 to 14 feet in height, with a 14 to 15
feet wide crown. The waterside slope is approximately 3H: 1V (horizontal: vertical),
while the landside slope is generally 2H: 1V. Maintenance access ramps exist at the
north end, mid-section, and south end of the proposed repair, allowing for access to the
5
levee crown. According to United State Army Corps of Engineers (USACE), standard
levee prism geometry should follow Table 2.2.1 below.
Table 2.2.1 – Standard Levee Prism Geometry
Levee Location
Crown Width
(feet)
Riverside Slope
(feet/feet)
Landside Slope
(feet/feet)
Freeboard
(feet)
River and
Tributary Levees
20
3H:1V
2H:1V
3
Bypass Levees
20
4H:1V
3H:1V
6
The crown width of the levee in the project area does not match with USACE’s standard
levee prism geometry but for this project purpose only erosion problem will be addressed
and no work will be done on levee prism.
SJR RM 71.5R is located at an outside bend of a tight meander (Radius of
Curvature/Channel Width < 2). The direction of flow of the San Joaquin River changes
from northeasterly to due west through the course of this bend. Consequently, the right
bank of this river bend is subject to significant erosional forces as flows are redirected to
the west. During 2006 and 2011 flood seasons, the portion of this repair site was about to
fail and emergency placement of revetment were required to protect the levee.
The eroded bank is typically 8 to 12 feet in height with slope gradients ranging
from 0.5H:1V to vertical. Overhanging (undercut) zones are also locally present and
commonly lead to tension cracks and caving of tall, narrow wedges. The tall vertical
height and mode of failure are indicative of sandy soils, which are exposed in the bank.
Photographs of the eroded bank are in Appendix A.
6
Aerial photographs from November 23, 2004 and May 5, 2009 (five flood
seasons) show ongoing erosion throughout the majority of the proposed repair site (see
Figure 2.3). Based on these photographs, erosion rates vary along the proposed reach
from a minimum of about 2 feet per year to a maximum of about 10 feet per year. Along
the downstream reach the average erosion rate is about 8 feet per year.
Figure 2.3 – Erosion Progression at SJR RM 71.5R
7
Chapter 3
ALTERNATIVE ANALYSIS
3.1 Introduction
Analysis of Alternatives is the analytical comparison of multiple alternatives to be
completed before committing resources to one project. The practice of comparing
multiple alternative solutions has long been a part of engineering practice. It can be done
by proposing a single alternative and justify this option or proposing multiple options
with the goal of choosing the best one. For this project purpose four alternatives have
been evaluated and the best alternative has been selected as a repair for the erosion site.
The best alternative will be able to mitigate the on-going erosion, will have minimum
environmental impact, will require minimum maintenance and minimum real estate land
acquisition, will have minimum impact on existing infrastructure and will comparative
cheaper than other alternatives.
3.2 Alternatives
3.2.1 Alternative 1 - No Action
Alternative 1 consists of no present action. Under this alternative, erosion will
continue along the exposed bank and into the already compromised levee prism.
Catastrophic failure is possible during a single storm or flood water event. Emergency
flood fighting efforts and repairs would be anticipated, as required during the 2006 flood
event and the 2010-2011 high water event. In addition, further erosion will remove the
existing vegetation as the bank migrates landward.
8
Alternative 1 requires no present expenditure. Future costs to implement
Alternatives 2 or 3 will likely escalate relative to their present costs due to on-going
erosion and the inflation of construction costs.
3.2.2 Alternative 2 – Waterside Repair
Alternative 2 consists of armoring the eroding bank of approximately 2,000 lineal
feet (including transitions) with rock slope protection (RSP). Specifications for the rock
have been presented later in this report based on site’s hydraulic and physical
characteristics. Figure 3.2.2.1 illustrates the extend and location of repair of Alternative
2. For this analysis, it has been considered that a minimum 2 feet thick rock slope
protection will be provided above summer mean water surface elevation at 2H: 1V slope,
10 feet wide riparian bench will be provided on 2 feet above summer mean water surface
elevation and launch rock (discussed later in this report) will be provided below summer
mean water surface elevation at 1.5H: 1V slope. 0.75 foot thick agricultural soil will be
provided on top of upper rock slope protection to help growth of vegetation. Typical
repair section for this alternative has been presented in Figure 3.2.2.1, and soft costs,
design estimate considerations and cost estimate for alternative 2 have been presented in
Table 3.2.2.1, Table 3.2.2.2 and Table 3.2.2.3 respectively. Alternative 2 mitigates ongoing erosion and enhances the stability of the existing stream bank. Real estate costs and
impacts on existing infrastructures and improvements are anticipated to be minimal under
this alternative. Maintenance cost associated with this Alternative is expected to be
minimal. Under this Alternative the levee height remains as originally constructed and no
additional protection is provided for flood/storm events greater than design flow.
9
Figure 3.2.2.1 - Alternative 2 Repair Footprint
The estimated cost for Alternative 2 is about $4.2 million a total and about $2,000.00 per
linear feet.
10
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Table
3.2.2.1 - Soft
Escalation to bid-point of construction
5%
Change order reserve
5%
Design and Engineering (Pre-Bid)1
10%
Design Contingency (Post-Bid)
3%
Engineering Support During Construction
2%
Permitting and Legal2
5%
Construction Management and Site
Inspection
5%
Estimated Soft Costs (total)
35%
11
Table 3.2.2.2 - Design Estimate Considerations for Alternative 2
Length of Repair (ft)
2000
Average waterside slope
2:1
Agricultural Soil Thickness (ft)
0.75
Average Riparian Bench Width(ft)
10
Bedding layer thickness (ft)
1 to 2
Table 3.2.2.3 - Cost Estimate for Alternative 2
Item
No.
Description
Unit
Quantity
Unit Price
Total Cost
1
Mobilization and
Demobilization
Lump
Sum
1
$225,000.00
$225,000.00
2
Clearing and Grubbing
Acre
3.00
$25,000.00
$75,000.00
3
Earthfill
Ton
9,987
$30.00
$299,610.00
4
Agricultural Soil
Ton
3,677
$35.00
$128,695.00
5
Bedding Layer
Ton
1,390
$51.00
$70,890.00
6
Rock Slope Protection
Ton
5,788
$55.00
$318,340.00
7
Launch Rock (Rockfill)
Ton
27,384
$50.00
1,369,200.00
8
Beaver Fence
9
Erosion Control Fabric
LF
3,909
$8.00
Sq
11,584
$9.00
Yd
Subtotal Construction Costs:
$31,272.00
$104,256.00
Environmental Mitigation Costs:
$2,622,263.00
$655,565.00
(25% of Subtotal Construction Cost)
Estimated Soft Costs:
$1,147,017.00
Estimated Total Costs:
$4.195,620.00
Total Estimated Repair Cost Per L.F.: 2,097.81
12
Notes:
1. Includes geotechnical exploration and topographic/bathymetric surveys.
2. Includes land and right-of-way and environmental permitting activities.
3.2.3 Alternative 3 – Setback Levee
Alternative 3 consists of the construction of a setback levee that parallels the
existing levee for approximately 3,000 feet including tie-ins. The levee would be
constructed approximately 25 feet from the landside toe of the existing levee providing
approximately 100 feet of additional erosion protection (See Figure 3.2.3.1 – Alternative
3 Repair Footprint). The setback levee will be constructed with a 3 Horizontal to 1
Vertical (H: V) waterside slope, 20-foot wide crown, and 2H: 1V or 3H: 1V landside
slope which is consistent with USACE’ standard levee prism geometry criteria. The crest
elevation will be designed to match the existing levee crown elevation and will tie-in
upstream and downstream of the erosion site.
This alternative will not directly mitigate on-going erosion and bank migration.
Ultimately, the setback levee could be subject to the same erosional processes if not
provided with some form of protection (i.e. rock slope protection). This alternative
would increase the duration of flood protection but will not provide protection against
erosion. Alternative 3 has a larger construction footprint relative to Alternative 2 but may
result in less environmental impacts by avoiding in-stream construction activities.
Maintenance associated with Alternative 3 is anticipated to be low until the river reaches
the setback levee.
13
Figure 3.2.3.1 - Alternative 3 Repair Footprint
The estimated cost for Alternative 3 is about $7.6 million a total and $2,500.00
per linear foot. The higher cost is attributed mostly to land acquisition, utility and
roadway relocation, and import material costs. Typical cross-section for this alternative
has been presented in Figure 3.2.3.2, and design estimate considerations and cost estimate
have been presented in Table 3.2.3.1 and Table 3.2.3.2 respectively. Soft cost will be
same as it is used for Alternative 2.
14
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Typical Repair
Section Use the Text Box Tools tab to change
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Table 3.2.3.1 - Design Estimate Considerations for Alternative 3
Length of Setback Levee (ft)
Approx. Height of Setback Levee (ft)
Approx. Length of Relocated Access Rd (ft)
3000
13
2000
Average Waterside Slope (H:V)
3:1
Average Landside Slope (H:V)
2:1
Crown Width (ft)
16
15
Table 3.2.3.2 - Cost Estimate for Alternative 3
Item
No.
1
2
4
5
6
Description
Mobilization and
Demobilization
Land Acquisition and
Temporary Easement
Clearing and Grubbing
Imported Embankment
Fill and Placement
Seeding and Erosion
Control
Unit
Quantity
Unit Price
Total $
Lump
Sum
1
$225,000.00
$225,000.00
Acre
20.0
$5000.00
$100,000.00
Acre
9.50
$25,000.00
$237,500.00
Ton
108,761
$35.00
$3,806,635.00
Acre
9.50
$18,000.00
$171,000.00
7
Levee Access Road
Sqft
42,000
$2.50
$105,000.00
8
SJC Board of Education
Access Road Relocation
Sqft
59,800
$7.50
$448,500.00
9
Power Line Relocation
LF
3,000
$50.00
$150,000.00
Each
1
$180,000.00
$180,000.00
Each
1
$80,000.00
$80,000.00
LT
3,000
$50.00
$150,000.00
10
11
12
18” Pump Intake
Relocation
Relocation of Gate and
Kiosk at School Entrance
GTE Telecommunication
Line Relocation
Subtotal Construction Costs:
$5,653,635.00
Estimated Soft Costs:
$1,978,772.00
Estimated Total Costs:
$7,632,407.00
Total Estimated Repair Cost Per L.F.: 2,544.00
3.2.4 Alternative 4 – Relief Channel
Alternative 4 consists of constructing a relief channel through the point bar
upstream of the proposed erosion repair site. The proposed design relief channel is
16
approximately 300 feet in width and 2000 feet in length (see Figure 3.2.4.1 – Alternative
4 Repair Footprint).
This alternative may reduce flow in the existing channel during moderate and
high water events. However, erosion is still anticipated during high flow conditions with
an unprotected bank. Additionally, this alternative may require permanent realignment of
the river channel and additional rock slope protection to other areas impacted by the new
channel alignment and hydraulics. Maintenance cost associated with this alternative will
be higher than other two alternatives as this alternative will have two channels to
maintain.
Alternative 4 includes the excavating of about 450,000 cubic yards of
unconsolidated soil with an impacted area of about 16 acres. Disposal will be off-site and
will require additional land acquisition.
17
Figure 3.2.4.1- Alternative 4 Repair Footprint
Alternative 4 will cost about $12 million to implement. Future costs may escalate due to
unknowns associated with future hydraulics and the need for additional rock slope
protection. Typical cross-section of this alternative has been presented in Figure 3.2.4.2,
and design estimate considerations and cost estimate have been presented in Table 3.2.4.1
and 3.2.4.2 respectively. Soft cost will be same as it is used for Alternative 2.
18
[Type a quote from the document or the summary of an interesting point. You can
Figure
3.2.4.2Typical Cross-Section
position
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the formatting of the pull quote text box.]
Table 3.2.4.1 - Design Estimate Considerations for Alternative 4
Approx. Length of Channel (ft)
2000
Approx. Depth of Channel (ft)
24
Channel Bottom width (ft)
200
Channel Side Slope (H:V)
2:1
Approx. Cross-sectional Area (sqft)
6000
Approx. Excavated Material (cy)
450,000
Table 3.2.4.2 - Cost Estimate for Alternative 4
Item
No.
1
2
3
Description
Mobilization and
Demobilization
Vegetation Clearing
Channel Excavation and
Hauled off Excavated
Material
Unit
Quantity
Unit Price
Lump
Sum
1
$225,000.00
$225,000.00
Acre
26.0
$25,000.00
$650,000.00
CY
450,000
$16.00
$7,200,000.00
Subtotal Construction Costs:
Total $
$8,075,000.00
19
Estimated Environmental Mitigation
Cost (10% of Construction Cost):
$807,500.00
Estimated Soft Costs:
$2,826,250.00
Estimated Total Costs:
$11,708,750.00
Total Estimated Repair Cost Per L.F.: $4,037.50
Note: Channel cross-sectional area was assumed to be same as the existing main channel
and depth is also considered to be same as main channel.
3.3 Recommended Alternative
Based on the analysis above, Alternative 2 – Waterside Repair has been selected
for remedy of erosion problem for the following reasons:

Alternative 2 provides direct mitigation to on-going erosion.

This Alternative requires minimal easement and land acquisition.

Implementation of Alternative 2 has minimal conflict with existing
infrastructure.

This has minimum environmental impact and has the ability to mitigate onsite.

This Alternative is the cheapest alternative among three possible alternatives
discussed in this report.
20
Chapter 4
DESIGN PARAMETERS FOR FEASIBLE ALTERNATIVE
4.1 Data Gathering and Processing
Detailed topographic and bathymetric surveys of the erosion site were conducted
by the California Department of Water Resources (DWR) and were used for design
purpose (Figure 4.4.1 to Figure 4.4.5). The survey used the North American Datum
(NAD83) and North American Vertical Datum 88 (NAVD88). The UNET model
developed by USACE was converted to HEC-RAS one dimensional steady state model
by PBS&J, was used as a base model to determine the hydraulic characteristics (i.e.
velocity, stage etc) of the channel.
The UNET is a one-dimensional unsteady open-channel flow model that can simulate
flow in a single reach on complex networks of interconnected channels. The UNET
model for the San Joaquin River Basin was developed by the US Army Corps of
Engineers Sacramento District. Unsteady flow UNET model for San Joaquin River Basin
was obtained and converted to steady-flow HEC-RAS models by PBS&J, a private
consultant for Department of Water Resources to evaluate and analyzed the hydraulic
characteristics of the San Joaquin River System. For this project purpose the steady state
Hydrological Engineering Center- River Analysis System (HEC-RAS) UNET model
converted by PB&J was used as a base model as sufficient geometry data was not
available to create a base model for this project purpose.
21
4.2 Hydraulic Analysis
The HEC-RAS 4.1.0 model developed by USACE will be used for this study. The
HEC-RAS is capable performing one-dimensional water surface profile calculation.
Water surface profiles are computed from one cross section to the next by solving the
energy equation with an iterative procedure called the standard step method. The energy
equation is written as follows:
Z2 + Y2 +
α2 V2
2g
2
= Z1 + Y1 +
α1 V1
2g
2
+ he
Where: Z1, Z2 = elevation of the main channel inverts in ft
Y1, Y2 = depth of water at cross sections in ft
V1, V2 = average velocities (total discharge/ total flow area) in ft/sec
α1, α2 = velocity weighting coefficients
g = gravitational acceleration in ft/sec2
he = energy head loss in ft
22
Following diagram shows the term of Energy Equation:
Figure 4.2.1 – Presentation of Terms in the Energy Equation (Gary W. Brunner, 2010)
The energy head loss (he) between two cross sections is comprised of friction losses and
contraction or expansion losses. The equation for the energy head loss is as follows:
he =LS̅f + C |
α2 V
2
2
2g
α1 V
-
1
2g
2
|
Where: L = discharge weighted reach length
S̅f = representative friction slope between two sections
C = expansion or contraction loss coefficient
The discharge weighted reach length, L, is calculated using the following equation:
L=
Llob ̅̅̅̅̅
Qlob + Lch ̅̅̅̅̅
Qch + Lrob ̅̅̅̅̅
Qrob
̅̅̅̅̅+ ̅̅̅̅̅
̅̅̅̅̅
Q
Q +Q
lob
ch
rob
23
Where Llob, Lch, Lrob = cross section reach lengths specified for flow in the left
overbank, main channel, and right overbank, respectively
̅̅̅̅̅
̅̅̅̅̅= arithmetic average of the flows between sections for the left
Qlob , ̅̅̅̅̅
Qch ,Q
rob
overbank, main channel, and right overbank, respectively
To determine total conveyance and the velocity coefficient for a cross section,
HEC-RAS subdivides the flow area into units for which the velocity is uniformly
distributed. The approach used in HEC-RAS is to subdivide flow in the overbank areas
using the input cross section n-value break points (locations where n-value change) as the
basis for subdivision (See Figure 4.2.2). The total conveyance for the cross section is
obtained by summing the three subdivision conveyances (left, channel, and right). HECRAS uses following equation to determine conveyance for the subdivisions:
Q=KS0.5
f
K=
1.486
2
AR ⁄3
n
Where: K = conveyance for subdivision
n = Manning’s roughness coefficient for subdivision
A = flow area for subdivision
R = hydraulic radius for subdivision (area / wetted perimeter)
24
Figure 4.2.2 – HEC-RAS Conveyance Subdivision Method (Gary W. Brunner, 2010)
HEC-RAS computes velocity coefficient (α) using the following equation:
(At )2 [
α=
K3lob K3ch K3rob
+
+
]
A2lob A2ch A2rob
K3t
Where: At = total flow area of the cross section
Alob, Ach, Arob = flow area of left overbank, main channel and right overbank,
respectively
Kt = total conveyance of the cross section
Klob, Kch, Krob = conveyance of left overbank, main channel and right overbank,
respectively
HEC-RAS compute friction loss using following equation:
Hf = S̅f L
Where, L = discharge weighted reach length
S̅f = representative friction slope for a reach which is calculated by the following
equation:
25
Q1 + Q2 2
S̅f = (
)
K1 + K2
Contraction and expansion losses in HEC-RAS are calculated by the following equation:
hce = C |
α1 V
1
2g
2
-
α2 V
2
2g
2
|
Where, C = the contraction and expansion coefficient
4.2.1 – Calibration of the Model
HEC-RAS model has been used for the hydraulic analysis of the project. HECRAS UNET model was used as a base model to do the analysis. The available San
Joaquin River hydraulic cross sections nearest to the site were selected from the UNET
model and interpolated to represent the extents of the eroded site. These sections were
then updated based on actual survey data. The survey data only covers the right half of
the channel since that is where the repair is needed. So the left half of the channel
sections are stayed unchanged as interpolated. This updated hydraulic model served as
the base model for the project. Figure 4.2.1.1 shows the alignment of the river and crosssection into the model.
United State Geological Survey (USGS) and DWR gauging station, SAN
JOAQUIN RIVER NEAR VERNALIS (VNS) which is located approximately 0.75 mile
upstream of SJR RM 71.5R site has been used to calibrate the model. Figure 4.2.1.2
shows the location of the Gauging station. The station provides both flow and stage data
at every 15 minutes. The model was run with a known flow and calibrated by changing
the n-values until the desired stage was obtained.
26
Project Area
RM 71.5R
Figure 4.2.1.1 – HEC-RAS Channel Alignment
27
Figure 4.2.1.2 – Location of VNS Gauging Station
Manning’s n-values obtained through the calibration process of the model has
been presented in the following table.
Table 4.2.1.1 – Manning’s n-Value
Manning’s n-value
Project Condition
Existing Condition
Left Overbank
Main Channel
Right Overbank
0.095
0.032
0.095
28
4.2.2 Simulation Run
Few simulation runs have been performed using calibrated model to find out the
maximum velocity the channel may experience and also the water surface elevation for
that particular flow. Several simulations have been performed in order to determine the
hydraulic characteristics of the system. Channel maximum velocity is required to
compute rock size to mitigate on-going erosion. For this purpose, the flow for what the
levee has been designed for (design flow) and project 100-year flow and few more
random flows were used for simulation run. The levee in this project has been designed to
convey the design flood of 52,000 cfs along San Joaquin River with a minimum
freeboard of 3.0 feet. The project 100 year peak flow is 79,650 cfs which was obtained
from UNET model. Hydraulic analysis for the existing system has been performed to find
out the maximum velocity. One simulation has been run with project design flow (52,000
cfs), one simulation with 100 year flow (79650 cfs) and six more simulations have been
run for different flow condition (70,000 cfs, 60,000 cfs, 40000 cfs, 30,000 cfs, 20,000 cfs,
and 10,000 cfs) . Simulations with flows lesser than 100 year flow have been run as the
channel may not experience maximum velocity at maximum flow. Maximum velocity
can occur at flow lower than 100 year flow or design flow. However, the simulation
result shows that the channel experience maximum velocity at 100 year flow and for that
flow there is no available freeboard and flow overtop the levee. The result of the
simulation has been presented in table 4.2.2.1.
29
Table 4.2.2.1 – HEC-RAS Output
River Station
Plan
71.73
71.73
71.73
71.73
71.73
71.73
71.73
71.73
100 YR
Design
70000
60000
40000
30000
20000
10000
Flow
Total
(cfs)
Min
Ch El
(ft)
W.S.
Elev
(ft)
Vel
Chnl
(ft/s)
Flow
Area
(sq ft)
Froude
# Chl
79650
52000
70000
60000
40000
30000
20000
10000
1.3
1.3
1.3
1.3
1.3
1.3
1.3
1.3
38.31
32.97
36.78
34.72
30.15
27.53
23.68
18.66
5.04
4.53
4.81
4.66
4.29
4.06
3.61
2.81
33668.1
22655.5
30468.8
26236
16896.6
9598.03
5885.3
3555.59
0.17
0.17
0.16
0.16
0.17
0.17
0.17
0.16
Upstream End of Repair
71.695
71.695
71.695
71.695
71.695
71.695
71.695
71.695
71.66
71.66
71.66
71.66
71.66
71.66
71.66
71.66
100 YR
Design
70000
60000
40000
30000
20000
10000
100 YR
Design
70000
60000
40000
30000
20000
10000
79650
52000
70000
60000
40000
30000
20000
10000
79650
52000
70000
60000
40000
30000
20000
10000
1.05
1.05
1.05
1.05
1.05
1.05
1.05
1.05
0.8
0.8
0.8
0.8
0.8
0.8
0.8
0.8
38.28
32.94
36.75
34.69
30.11
27.49
23.65
18.63
38.29
32.95
36.76
34.7
30.13
27.52
23.68
18.64
5.10
4.58
4.87
4.71
4.34
4.11
3.59
2.75
4.53
3.98
4.3
4.13
3.69
3.41
2.88
2.14
33154
22183.5
29966.5
25751.3
16442.1
9175.56
5863.31
3636.37
33866.1
22952.5
30689.6
26500.8
17242.6
9558.68
6998.49
4670.45
0.17
0.17
0.16
0.17
0.17
0.17
0.17
0.15
0.15
0.14
0.14
0.14
0.14
0.14
0.13
0.12
71.625
71.625
71.625
100 YR
Design
70000
79650
52000
70000
0.56
0.56
0.56
38.24
32.9
36.71
4.85
4.29
4.61
32873.9
22004.7
29713.1
0.16
0.15
0.15
30
Table 4.2.2.1 (Contd.)
Flow
Min
W.S.
Total
Ch El Elev
(cfs)
(ft)
(ft)
60000
0.56
34.65
40000
0.56
30.07
30000
0.56
27.46
20000
0.56
23.63
10000
0.56
18.61
Vel
Chnl
(ft/s)
4.44
4.01
3.69
3.13
2.31
Flow
Froude
Area
# Chl
(sq ft)
25543.3 0.15
15890.2 0.15
9145.93 0.15
6511.7
0.14
4323.92 0.12
River Station
Plan
71.625
71.625
71.625
71.625
71.625
60000
40000
30000
20000
10000
71.59
71.59
71.59
71.59
71.59
71.59
71.59
71.59
100 YR
Design
70000
60000
40000
30000
20000
10000
79650
52000
70000
60000
40000
30000
20000
10000
0.31
0.31
0.31
0.31
0.31
0.31
0.31
0.31
38.19
32.84
36.66
34.6
30.02
27.4
23.57
18.57
5.12
4.59
4.88
4.72
4.3
3.99
3.43
2.55
31933.5
20788.3
28791.5
24634.3
15403.1
8665.65
5965.42
3914.15
0.17
0.17
0.16
0.17
0.17
0.16
0.16
0.14
71.555
71.555
71.555
71.555
71.555
71.555
71.555
71.555
100 YR
Design
70000
60000
40000
30000
20000
10000
79650
52000
70000
60000
40000
30000
20000
10000
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
38.17
32.82
36.64
34.58
29.99
27.38
23.55
18.55
5.11
4.54
4.85
4.69
4.25
3.94
3.38
2.49
31793.8
21059.1
28673.7
24474.7
15598.1
8825.41
6086.69
4012.86
0.17
0.16
0.16
0.16
0.16
0.16
0.15
0.13
71.52
71.52
71.52
71.52
71.52
71.52
71.52
71.52
100 YR
Design
70000
60000
40000
30000
20000
10000
79650
52000
70000
60000
40000
30000
20000
10000
-0.19
-0.19
-0.19
-0.19
-0.19
-0.19
-0.19
-0.19
38.15
32.8
36.62
34.56
29.97
27.35
23.53
18.53
5.06
4.49
4.79
4.63
4.2
3.88
3.32
2.43
31993.2
21361.6
28915.7
24826.9
15815.2
9011.62
6294.88
4118.81
0.16
0.16
0.16
0.16
0.16
0.16
0.15
0.13
31
River Station
Plan
71.486
71.486
71.486
71.486
71.486
71.486
71.486
71.486
100 YR
Design
70000
60000
40000
30000
20000
10000
Table 4.2.2.1 (Contd.)
Flow
Min
W.S.
Total
Ch El Elev
(cfs)
(ft)
(ft)
79650
0.66
38.14
52000
0.66
32.8
70000
0.66
36.61
60000
0.66
34.55
40000
0.66
29.97
30000
0.66
27.35
20000
0.66
23.53
10000
0.66
18.53
71.451
71.451
71.451
71.451
71.451
71.451
71.451
71.451
100 YR
Design
70000
60000
40000
30000
20000
10000
79650
52000
70000
60000
40000
30000
20000
10000
1.51
1.51
1.51
1.51
1.51
1.51
1.51
1.51
38.15
32.8
36.62
34.56
29.98
27.36
23.53
18.53
4.46
3.87
4.22
4.05
3.53
3.17
2.63
1.86
33677.6
22436.4
30493.2
25801.9
17055.3
10420
7642.24
5373.08
0.14
0.13
0.14
0.14
0.13
0.12
0.11
0.09
71.417
71.417
71.417
71.417
71.417
71.417
71.417
71.417
100 YR
Design
70000
60000
40000
30000
20000
10000
79650
52000
70000
60000
40000
30000
20000
10000
2.37
2.37
2.37
2.37
2.37
2.37
2.37
2.37
38.14
32.78
36.6
34.54
29.96
27.34
23.51
18.51
4.45
3.91
4.23
4.04
3.58
3.23
2.71
1.97
33734.9
21962.3
30527.7
26290.5
16653.3
10119.6
7376.6
5088.05
0.14
0.14
0.14
0.14
0.14
0.13
0.12
0.1
71.382
71.382
71.382
71.382
71.382
71.382
100 YR
Design
70000
60000
40000
30000
79650
52000
70000
60000
40000
30000
3.22
3.22
3.22
3.22
3.22
3.22
38.1
32.75
36.57
34.51
29.91
27.29
4.64
4.09
4.42
4.24
3.81
3.47
33560.9
22435.2
30335.3
26047.2
16002.1
9587.1
0.15
0.15
0.15
0.15
0.14
0.14
Vel
Chnl
(ft/s)
4.86
4.25
4.6
4.42
3.93
3.58
3
2.14
Flow
Froude
Area
# Chl
(sq ft)
32509.2 0.16
21729.2 0.15
29364.7 0.15
25143.1 0.15
16269.3 0.15
9560.01 0.14
6804.72 0.13
4666.62 0.11
32
River Station
Plan
71.382
71.382
20000
10000
71.35
100 YR
71.35
Design
71.35
70000
71.35
60000
71.35
40000
71.35
30000
71.35
20000
71.35
10000
Downstream End of Repair
71.313
100 YR
71.313
Design
71.313
70000
71.313
60000
71.313
40000
71.313
30000
71.313
20000
71.313
10000
4.3
Table 4.2.2.1 (Contd.)
Flow
Min
W.S.
Total
Ch El Elev
(cfs)
(ft)
(ft)
20000
3.22
23.47
10000
3.22
18.48
Vel
Flow
Froude
Chnl
Area
# Chl
(ft/s) (sq ft)
2.92 6905.49 0.13
2.14 4678.13 0.11
79650
52000
70000
60000
40000
30000
20000
10000
4.07
4.07
4.07
4.07
4.07
4.07
4.07
4.07
38.07
32.71
36.54
34.47
29.85
27.23
23.41
18.42
4.74
4.28
4.54
4.4
4.1
3.81
3.32
2.6
33165.2
21926.2
29919.1
25579.4
15065.5
8752.43
6119.72
3846.33
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.15
79650
52000
70000
60000
40000
30000
20000
10000
4.92
4.92
4.92
4.92
4.92
4.92
4.92
4.92
38.06
32.69
36.53
34.46
29.84
27.21
23.38
18.39
4.66
4.2
4.46
4.32
3.98
3.75
3.31
2.64
33664.7
22335.2
30402.4
26025.6
16415.9
9436.76
6278.28
3783.74
0.16
0.16
0.15
0.16
0.16
0.16
0.16
0.15
Riprap Design
The ability of riprap slope protection to resist the erosive forces of channel flow
depends on the interrelation of the following factors: stone shape, size, weight, and
durability; riprap gradation and layer thickness; and channel alignment, cross section,
gradient, and velocity distribution.
33
4.3.1 Stone Shape
Riprap should be blocky in shape rather than elongated. The stone should have
sharp, angular, clean edges as the angular and cubical stone provide more resistant in
movement than rounded stone.
4.3.2 Stone Size and Weight
The ability of riprap revetment to resist erosion is related to the size and weight of
stones. The relation between size and weight of stone is described by the following
equation:
1⁄
3
6W%
D% = (
)
πγs
Where D% = equivalent-volume spherical stone diameter, ft
W% = weight of individual stone having diameter of D%
γs = saturated surface dry specific or unit weight of stone, pcf
4.3.3 Layer Thickness
All stone should be contained within the riprap layer thickness to provide
maximum resistance against erosive forces. Layer thickness should not be less than D100
(spherical diameter of the upper limit W100 stone) or less than 1.5 times of D50 (spherical
diameter of the upper limit W50 stone). When the riprap is placed under water, the
thickness determined by using D100 or D50 should be increased by 50 percent for
uncertainties associated with this type of placement.
34
4.3.4 Side Slope Inclination
Side slope should ordinarily not be steeper than 1V on 1.5H, except in special
cases where it may be economical to use larger hand-placed stone keyed into the bank, to
provide stability of riprap slope protection.
4.3.5 Channel Roughness, Shape, Alignment, and Gradient
As boundary shear forces and velocities depend on channel roughness, shape,
alignment, and invert gradient, these factors must be considered in determining the size
of stone required for riprap revetment. Manning’s n for riprap placed in the dry (section is
dry during placement of riprap) can be calculated using the following form of Strickler’s
equation:
1⁄
6
n = K[D90 (min)]
Where K = 0.034 for velocity and stone size calculation
D90(min) = size of which 90 percent of sample is finer, from minimum or lower
limit curve of gradation specification, ft
4.3.6 Selection of Rock Size
Rock size computation should be conducted for flow condition that produces
maximum velocities at the riprap boundary. The method for determining rock size uses
depth-average local velocity. Local velocity and local flow depth are used in the
procedure to quantify the imposed forces. Riprap size and unit weight quantify the
resisting force of the riprap. The depth average local velocity over the slope, Vss can be
calculated at a point 20 percent of the slope length from the toe of slope. A two
dimensional hydraulic analysis is preferable to determine Vss. However, Vss also can be
35
determined by using the average channel velocity, Vavg using following equation
(USACE, 1990 EM 1110-2-2302):
Vss
Vavg
=1.74-0.52log(R⁄W)
Where Vavg = average channel velocity at the upstream end of bend
R = center-line radius of the bend
W = water surface width
R and W are based on flow in the main channel only and do not include overbank areas.
The basic equation for the representative rock size in straight or curved channels is as
follows:
1⁄
2
γw
D30 =Sf Cs CvCT d [(γ - γ )
s
w
2.5
V
√K1 gd
]
Where; D30 = riprap size of which 30 percent is finer by weight
Sf = safety factor (safety factor used to increase rock sizes to resist hydrodynamic
and a variety of nonhydrodynamic-imposed forces and/or uncontrollable physical
conditions. The minimum value of safety factor is 1.1)
Cs = stability coefficient for incipient failure = D85/D15 = 1.7 to 5.2
= 0.30 for angular rock
= 0.375 for rounded rock
Cv = vertical velocity distribution coefficient
= 0.10 for straight channels, inside of bends
= 1.283 – 0.2lg(R/W), outside of bends (1 for (R/W) > 26)
36
CT = thickness coefficient
d = local depth of flow (same location as V)
γw= unit weight of water
V = local depth average velocity
K1 = side slope correction factor
g = gravitational constant
The relation between D30 and D50 is follows:
1
D85 ⁄3
D50 = D30 ( )
D15
Where; D30 = riprap size of which 30 percent is finer by weight
D50 = riprap size of which 50 percent is finer by weight
D85 = riprap size of which 85 percent is finer by weight
D15 = riprap size of which 15 percent is finer by weight
For this project purpose, CHANLPRO software, developed by USACE was used
to find the required minimum rock size. CHANLPRO provides riprap design guidance
for channels subjected to high velocity forces with low turbulence flows. The program
gives different stable gradation results depending on the depth, water surface width, bend
radius, and local velocity. The CHANLPRO program version 2.0 (USACE, 1998) was
used to select a gradation to adequately protect the site. The program uses the equations
that were presented in section 4.3.6. Selection of Rock Size to find gradation of riprap.
Average channel velocity at upstream end of bend (River Station 71.695) has been used
as an input and the program will calculate the local depth average velocity. From Table
37
4.2.2.1, at River Station 71.695 average channel velocity is 5.10 ft/sec but for design
purpose an average velocity of 5.5 ft/sec has been used. The following parameters were
used as input to the model
Specific weight, pcf = 150
Local flow depth, ft = 32.0
Average channel velocity, ft/sec = 5.5
Channel bank slope, ft/ft = 1.5H:1V
Center-line radius of the bend, R, ft = 250
Water surface width, W, ft = 250
The computer program (CHANLPRO) identified D50 size of minimum 10.5 inches is
required for this project condition. Program input and output is attached in Appendix B.
4.3.7 Gradation of Riprap
The gradation of rock in riprap revetment affects the riprap’s resistant to erosion.
Rock should be reasonably well graded throughout the in-place layer thickness. The rock
shape should be angular with the minimum dimension of the rock not less than one third
of the maximum dimension. Slope protection rock should be clean, free of dirt or mud,
loose concrete or mortar, trash, and organic matter. Table 4.3.7.1 shows the proposed
gradation to be used for this site based on CHANLPRO result:
38
Table 4.3.7.1 – Gradation Table
Size
D100
D90
D50
D30
D15
D5
4.4
Diameter (in)
Max.
18.0
12.0
9.5
3.0
Min.
13.3
12.7
10.5
8.8
7.1
0
Weight (Ib)
Max.
265
78
39
10
Min.
106
94
53
31
17
0
Repair Section Design
According to section 4.3.3, the minimum thickness of riprap for repair section
will be 18 inches as the D50 size of rock is 12 inches. The maximum thickness of repair
section depends on its impact to river hydraulics as this repair encroaches into the
channel available conveyance area and also depends on cost as cost goes up with
thickness increment. Most of the places along the repair length require more than
minimum required thickness of riprap as erosion in some places were more than other
places resulted in irregular channel bank. Various layer thicknesses (atleast 18 inches)
have been provided all along the repair length to provide smooth and regular bank to the
channel and to improve hydraulics of the existing system. The repair section comprises
three major components: 1. Launch rock, 2. Riparian bench, and 3. upper rock slope
protection. Typical cross section of the repair has been presented in Figure 4.4.1. and
repair footprint has been presented in Figure 4.4.2., Figure 4.4.3., Figure 4.4.4., and
Figure 4.4.5.
39
4.4.1 Launch Rock
Toe scour is the most frequent cause of failure for wide variety of protection
technique including rock revetments. Channels with highly erodible bed and banks can
experience significant scour along the toe of the new revetment. This can be prevented by
providing sufficient launch rock. Launch rock is defined as the rock that is placed along
expected erosion areas at an elevation above the zone of attach. As the attack and
resulting erosion occur below the stone, the stone is undermined and rolls/ slides down
the slope, stopping the erosion. Thickness of launch rock should be 1.5 times of thickness
of upper rock slope protection for uncertainties associated with this the placement of rock
under water.
4.4.2 Riparian Bench
Riparian bench is provided at the top of launch rock typically at 2 to 4 feet above of
summer mean water surface elevation. For this project a riparian bench is set at elevation
14.7 ft (summer mean plus 2 ft). See Appendix C for summer mean elevation calculation
form CDEC data. The purpose of providing riparian bench is to create habitat for
restoration of vegetation lost due to bank erosion.
4.4.3 Rock Slope Protection
The upper rock slope protection sits on top of the riparian bench. The height that riprap is
placed up a levee or bank can vary substantially and is site specific. For the project site,
the height has been determined as the height of the existing berm of the levee. The slope
of the riprap should not be steeper than 1.5H: 1V for stability purpose and can be as flat
as 3H: 1V without affecting the existing hydraulics of the system. For this project, a slope
40
of 2H: 1V has been used as 3H:1V slope will encroach too much into channel available
conveyance area and 1.5H:1V slope will be too steep to do regular maintenance. The void
between the rock will be filled with agricultural soil and 9 inches thick layer of
agricultural soil will be placed on top of rock slope to facilitate growth of vegetation.
Figure 4.4.1- Typical Cross-Section
41
Figure 4.4.2 - Repair Footprint - Plan 1 of 3
42
Figure 4.4.3- Repair Footprint - Plan 2 of 3
43
Figure 4.4.4 - Repair Footprint - Plan 3 of 3
44
Figure 4.4.5 - Full Repair Footprint
45
46
Chapter 5
EVALUATION OF REPAIR IMPACT ON EXISTING RIVER HYDRAULICS
5.1 Introduction
The proposed repair will encroach into the available conveyance area. The rock
slope protection and proposed vegetation on the main channel repaired slope may also
increase bank roughness for stream flow computations. A hydraulic impact analysis has
been prepared to analyze the anticipated impacts of the proposed repairs on the San
Joaquin River flow conveyance capacity in the vicinity of the repair.
5.2 Hydraulic Analysis
The purpose of the hydraulic modeling and analysis is to verify the hydraulic
impacts of the proposed projects based on USACE design criteria. UASCE generally
requires that based on existing conditions, the project water surface elevation not increase
more than 0.1 foot and not encroach upon the minimum design freeboard of 3.0 feet. To
analyze the impacts of the proposed repair, the calibrated model which was used for
existing condition has been used as a base model. To simulate the post-project condition,
the sections within the site limits were updated to include the rock slope protection
repairs and the Manning’s roughness values were revised in each section to account for
the rock slope protection and fully developed vegetation. The repair site is within the
main channel and it will be covered with different plants on the lower and upper zones of
the bank in addition to rock slope protection. These roughness changes within the main
channel were considered in the modeling by assuming new Manning’s coefficients for
main channel sections where the roughness changes. As the repair is on main channel,
47
during high flow this section will be covered with water and will provide less effective
resistance. Based on Ven Te Chow (Open-Channel Hydraulics, 1973, Table 5-6), for
irregular and rough section in major stream, the value of n varies from 0.035 to 0.1.
Table 5.2.1 shows the Manning’s n-values that have been used in the model.
Table 5.2.1 – Manning’s n-Value for Post Repair Condition
Project
Condition
Existing
Condition
Post Project
Condition
Left
Overbank
Main
Channel
Repaired
Slope
Right
Overbank
0.095
0.032
--
0.095
0.095
0.032
0.045
0.095
In order to determine the hydraulic impacts of the proposed repair, this project
uses the 100 year peak flow (79,650 cfs) as baseline for the engineering design. The
model also has been run for design flow (52,000 cfs) just to evaluate the impact on the
design condition of the system.
The simulations results show that the repair has very insignificant impact on water
surface elevation which is the main concern of the encroachment into the waterway. For
100 year flood (79,650 cfs), flow overtop the levee for existing condition and with repair
on it with a maximum water surface elevation increment of 0.03 ft which is insignificant
compare to USACE allowable limit. USACE allows a water surface elevation increment
upto 0.1 ft for any encroachment into the waterway for 100 year flow. For design flood
(52,000 cfs), the water surface elevation increment due to encroachment into the river is
also 0.03 ft which is also very insignificant compare to available conveyance area. The
result of the analysis is presented in table and figures.
48
Figure 5.2.1 shows the repair section on existing system with 100-year water
surface elevation from River Station 71.59 to 71.486 (see Appendix D for more. Figure
5.2.2 represents the 100-year and design flow water surface elevation for existing system
and post project condition. The figure depicts that there is very little or no change in
water surface elevation due to repair on the right bank of the river. Figure 5.2.3 shows the
velocity profiles for 100-year and design flow for existing condition and post project
condition on left bank, right bank and main channel. The velocity profiles portray that
there is insignificant impact of repair on velocity of the river system. In all figure
legends, E-100 YR means existing condition with 100-year flow, PR-100 YR means post
project condition with 100-year flow, Design- 52000 means existing condition with
design flow of 52000 cfs and Post-Design means post repair condition with design flow.
49
Figure 5.2.1 – Cross-Section with Repair on Existing System with 100-Year Water
Surface Elevation (From River Station 71.59 to 71.486)
50
Figure 5.2.2 – Water Surface Profile for 100–Year and Design Flow for Existing and Post
Project Condition
51
Project Location
Figure 5.2.3 – Velocity Profile for 100–Year and Design Flow for Existing and Post
Project Condition
52
Table 5.2.2 shows the change in water surface elevation (WSE) and velocity (V) due to
repair in the main channel.
Table 5.2.2 – Comparison of WSE and V for Existing Condition and Post Repair
Condition.
River
Station
Plan
Q Total
Min
Ch El
W.S.
Elev
Change
in WSE
Vel
Chnl
Change
in Vel
(ft)
39.23
39.24
33.83
33.86
(ft/s)
6.06
6.06
5.01
5.00
(ft/s)
E - 100 YR
PR - 100 YR
E - Design
PR - Design
(ft)
-1.02
-1.02
-1.02
-1.02
(ft)
72.567
72.567
72.567
72.567
(cfs)
79650
79650
52000
52000
72.55
72.55
72.55
72.55
E - 100 YR
PR - 100 YR
E - Design
PR - Design
79650
79650
52000
52000
-0.02
-0.02
-0.02
-0.02
39.03
39.05
33.73
33.75
0.02
72.4
72.4
72.4
72.4
E - 100 YR
PR - 100 YR
E - Design
PR - Design
79650
79650
52000
52000
-5.64
-5.64
-5.64
-5.64
38.4
38.42
33.28
33.3
0.02
72.06
72.06
72.06
72.06
E - 100 YR
PR - 100 YR
E - Design
PR - Design
79650
79650
52000
52000
10.81
10.81
10.81
10.81
38.53
38.55
33.24
33.27
0.02
71.8
71.8
71.8
71.8
E - 100 YR
PR - 100 YR
E - Design
PR - Design
79650
79650
52000
52000
1.8
1.8
1.8
1.8
38.38
38.39
33.04
33.07
0.01
71.765
71.765
E - 100 YR
PR - 100 YR
79650
79650
1.55
1.55
38.35
38.37
0.02
0.01
0.03
0.02
0.02
0.03
0.03
7.11
7.11
5.64
5.63
0.00
-0.01
0.00
-0.01
8.88
8.87
7.03
7.02
-0.01
5.07
5.06
4.36
4.35
-0.01
4.97
4.97
4.44
4.43
0.00
5.00
5.00
-0.01
-0.01
-0.01
0.00
53
Contd Table 5.2.2
River
Station
Plan
Q Total
Min
Ch El
W.S.
Elev
Change
in WSE
Vel
Chnl
Change
in Vel
(cfs)
(ft)
(ft)
(ft)
(ft/s)
(ft/s)
71.765
71.765
E - Design
PR - Design
52000
52000
1.55
1.55
33.01
33.03
0.02
4.50
4.49
-0.01
71.73
71.73
71.73
71.73
E - 100 YR
PR - 100 YR
E - Design
PR - Design
79650
79650
52000
52000
1.3
1.3
1.3
1.3
38.31
38.33
32.97
33
0.02
5.04
5.03
4.53
4.52
-0.01
5.10
5.09
4.58
4.58
-0.01
4.53
4.58
3.98
4.03
0.05
4.85
4.88
4.29
4.35
0.03
5.12
5.22
4.59
4.69
0.10
5.11
0.01
0.03
-0.01
Upstream End of Repair
71.695
71.695
71.695
71.695
E - 100 YR
PR - 100 YR
E - Design
PR - Design
79650
79650
52000
52000
1.05
1.05
1.05
1.05
38.28
38.3
32.94
32.96
0.02
71.66
71.66
71.66
71.66
E - 100 YR
PR - 100 YR
E - Design
PR - Design
79650
79650
52000
52000
0.8
0.8
0.8
0.8
38.29
38.31
32.95
32.98
0.02
71.625
71.625
71.625
71.625
E - 100 YR
PR - 100 YR
E - Design
PR - Design
79650
79650
52000
52000
0.56
0.56
0.56
0.56
38.24
38.26
32.9
32.92
0.02
71.59
71.59
71.59
71.59
E - 100 YR
PR - 100 YR
E - Design
PR - Design
79650
79650
52000
52000
0.31
0.31
0.31
0.31
38.19
38.2
32.84
32.84
0.01
71.555
E - 100 YR
79650
0.06
38.17
0.01
71.555
PR - 100 YR
79650
0.06
38.18
0.02
0.03
0.02
0.00
5.12
0.00
0.05
0.06
0.10
54
Contd Table 5.2.2
River
Station
Plan
Q Total
Min
Ch El
W.S.
Elev
Change
in WSE
Vel
Chnl
Change
in Vel
(cfs)
(ft)
(ft)
(ft)
(ft/s)
(ft/s)
71.555
71.555
E - Design
PR - Design
52000
52000
0.06
0.06
32.82
32.83
0.01
4.54
4.58
0.04
71.52
71.52
71.52
71.52
E - 100 YR
PR - 100 YR
E - Design
PR - Design
79650
79650
52000
52000
-0.19
-0.19
-0.19
-0.19
38.15
38.16
32.8
32.81
0.01
5.06
5.06
4.49
4.52
0.00
71.486
71.486
71.486
71.486
E - 100 YR
PR - 100 YR
E - Design
PR - Design
79650
79650
52000
52000
0.66
0.66
0.66
0.66
38.14
38.15
32.8
32.79
0.01
4.86
4.94
4.25
4.35
0.08
71.451
71.451
71.451
71.451
E - 100 YR
PR - 100 YR
E - Design
PR - Design
79650
79650
52000
52000
1.51
1.51
1.51
1.51
38.15
38.15
32.8
32.8
0.00
4.46
4.54
3.87
3.97
0.08
71.417
71.417
71.417
71.417
E - 100 YR
PR - 100 YR
E - Design
PR - Design
79650
79650
52000
52000
2.37
2.37
2.37
2.37
38.14
38.14
32.78
32.78
0.00
4.45
4.46
3.91
3.93
0.01
71.382
71.382
71.382
71.382
E - 100 YR
PR - 100 YR
E - Design
PR - Design
79650
79650
52000
52000
3.22
3.22
3.22
3.22
38.1
38.1
32.75
32.74
0.00
4.64
4.66
4.09
4.13
0.02
71.35
71.35
E - 100 YR
PR - 100 YR
79650
79650
4.07
4.07
38.07
38.07
4.74
4.74
0.00
0.01
-0.01
0.00
0.00
-0.01
0.00
0.03
0.10
0.10
0.02
0.04
55
River
Station
Plan
71.35
E - Design
71.35
PR - Design
Downstream End of Repair
71.313
E - 100 YR
71.313
PR - 100 YR
71.313
E - Design
71.313
PR - Design
71.28
71.28
71.28
71.28
E - 100 YR
PR - 100 YR
E - Design
PR - Design
Contd Table 5.2.2
Min
W.S.
Q Total
Ch El
Elev
(cfs)
(ft)
(ft)
Change
in WSE
(ft)
Vel
Chnl
(ft/s)
Change
in Vel
(ft/s)
52000
52000
4.07
4.07
32.71
32.71
0.00
4.28
4.28
0.00
79650
79650
52000
52000
4.92
4.92
4.92
4.92
38.06
38.06
32.69
32.69
0.00
4.66
4.66
4.20
4.20
0.00
79650
79650
52000
52000
5.78
5.78
5.78
5.78
38.05
38.05
32.67
32.67
0.00
4.57
4.57
4.13
4.13
0.00
0.00
0.00
0.00
0.00
56
Chapter 6
CONCLUSIONS AND RECOMMENDATIONS
6.1 Conclusions
This chapter provides a general discussion of the conclusions relating to this study
and ideas for opportunities for future work. The purpose of this study was to evaluate the
different alternatives to mitigate an erosion problem and select the most feasible
alternative, determine cross-section of the selection alternative, and evaluate the
hydraulic impact of the repair to the existing river hydraulics. The alternative that was
selected is an in-place rock slope protection. The parameters that are required to
determine the size of rock and cross-section of the rock slope protection were obtained by
a one dimensional steady stead hydraulic analysis using HEC-RAS hydraulic model. As
the repair was an on-site repair and it encroached into available conveyance area of the
existing river system, a hydraulic analysis using HEC-RAS hydraulic model was
performed to evaluate the impact of the repair into the system.
The results of the hydraulic analysis indicate that the repair has very little or
insignificant impact to the channel hydraulics. So the selected alternative is the cheapest
and most appropriate alternative for this particular case and which can be implemented
without affecting the channel hydraulics adversely. If the alternative affected the channel
hydraulic system adversely, another alternative (in this case set back levee) would be
considered to mitigate the erosion problem.
The HEC-RAS results show that the water overtops the levee for 100-year flow but
raising the height of the levee was not considered during this analysis and design
57
procedure. The levee height increment at this particular location will transfer the flow
downstream which can create overtopping issue at the downstream of system. A system
wide evaluation is required to determine the impact of levee height increment at any
particular location.
6.2 Recommendations
In this analysis, only one dimensional steady state hydraulic analysis was
performed to determine velocity and water surface elevation of the channel. One
dimensional analysis provides channel average velocity at any particular cross-section. It
would be helpful to utilize different software and perform a two-dimensional analysis and
compare the results.
Armoring on a particular section of a bank could affect impact the other areas of
the channel since the river will no longer be able to freely meander along the repair
length. It would be very interesting subject to analyze how the river is going to behave
after repair – is it going to erode the inner point bar and where the sediment is going to be
stored etc.
Also this study did not consider stability issue during the analysis. Stability
analysis for existing condition and post project condition can be performed to see the
impact of the repair to the stability of the system and enhance the findings of the study.
During this study, no seepage analysis was performed. Seepage analysis for existing
system can be performed and if the results indicate that the system is susceptible to
seepage, a remedy for the seepage issue can be analyzed and strengthen the system.
58
APPENDIX A
Site Photographs
59
RSP placed in
2006
Levee
Crown
Near vertical
eroded bank
Photograph 1 - View upstream (east) of eroded bank at SJR RM 71.5R. Note
RSP placed in 2006 along levee’s waterside slope and near vertical bank.
RSP from 2006
emergency repair
Photograph 2 - View downstream (north) of SJR RM 71.5R erosion site, from
approximate Station 12+00 (Levee Mile 2.8, Unit 1).
60
Power poles and lines
along access road north
of levee
Localized
undercut bank
and caving
Photograph 3 - View upstream (east) from approximate Station 31+50 (Levee
Mile 2.4, Unit 1) of SJR RM 71.5R erosion site.
RSP from 2006
emergency repair
Photograph 4 – View downstream (north) from approximate Station 21+00 (Levee
Mile 2.6, Unit 1) of SJR RM 71.5R erosion site.
61
Photograph 6 – Close-up of existing RSP at SJR RM 71.5R from 2006 emergency
repair.
62
APPENDIX B
CHANLPRO Program - Input and Output
63
PROGRAM OUTPUT FOR A NATURAL CHANNEL SIDE SLOPE RIPRAP,
BENDWAY
INPUT PARAMETERS
SPECIFIC WEIGHT OF STONE,PCF
150.0
MINIMUM CENTER LINE BEND RADIUS,FT
WATER SURFACE WIDTH,FT
LOCAL FLOW DEPTH,FT
250.0
250.0
32.0
CHANNEL SIDE SLOPE,1 VER: 1.50 HORZ
AVERAGE CHANNEL VELOCITY,FPS
5.50
COMPUTED LOCAL DEPTH AVG VEL,FPS
8.71
(LOCAL VELOCITY)/(AVG CHANNEL VEL)
1.58
SIDE SLOPE CORRECTION FACTOR K1
.71
CORRECTION FOR VELOCITY PROFILE IN BEND
RIPRAP DESIGN SAFETY FACTOR
1.50
1.22
64
SELECTED STABLE GRADATIONS
ETL GRADATION
NAME
COMPUTED D30(MIN) D100(MAX) D85/D15 N=THICKNESS/ CT
THICKNESS
D30 FT
2
FT
.48
IN
D100(MAX)
12.00
1.70
IN
NOT STABLE
3
.61
.61
15.00
1.70
1.45
.90
21.7
4
.68
.73
18.00
1.70
1.00
1.00
18.0
D100(MAX)
IN
LIMITS OF STONE WEIGHT,LB
FOR PERCENT LIGHTER BY WEIGHT
100
50
D30(MIN) D90(MIN)
FT
FT
15
15.00
153
61
45
31
23
10
.61
.88
18.00
265
106
78
53
39
17
.73
1.06
EQUIVALENT SPHERICAL DIAMETERS IN INCHES
D100(MAX) D100(MIN) D50(MAX) D50(MIN) D15(MAX) D15(MIN)
15.0
11.1
10.0
8.8
7.9
6.0
18.0
13.3
12.0
10.5
9.5
7.1
65
APPENDIX C
CDEC Data – Summer Water Surface Elevation Calculation
66
ID of CDEC Station: VNS
River Basin: San Joaquin River
Hydrologic Area: San Joaquin River
Latitude: 37.676041 degree N
Longitude: 121.266327 degree W
Operator: USGS and DWR
Datum: NGVD 1929
Monthly Average Stage Data from VNS Station:
MonthYear
1/1993
1/1994
1/1995
1/1996
1/1997
1/1998
1/1999
1/2000
1/2001
1/2002
1/2003
1/2004
1/2005
1/2006
1/2007
1/2008
1/2009
10/1993
10/1994
10/1995
10/1996
Stage
(Monthly
Average), ft
12.37511547
9.774007628
11.56290937
10.97827957
28.40518317
13.99120606
12.92887525
9.957154363
10.01223761
10.3511454
9.498107229
9.327528635
12.82126344
19.17044355
11.28972709
12.68067231
8.81
11.42265544
……
14.30373927
10.99426643
MonthYear
10/1997
10/1998
10/1999
10/2000
10/2001
10/2002
10/2003
10/2004
10/2005
10/2006
10/2007
10/2008
11/1993
11/1994
11/1995
11/1996
11/1997
11/1998
11/1999
11/2000
11/2001
Stage
(Monthly
Average), ft
11.32933691
14.2226198
10.40490757
10.78563205
9.612440233
9.140513196
9.586510051
9.383249182
10.86501344
13.08192491
11.21809694
8.485551075
9.783427118
8.999682522
10.99143606
11.15590278
10.50114747
11.76810732
9.990961957
10.2926093
9.731292984
67
Continued Table
MonthYear
11/2002
11/2003
11/2004
11/2005
11/2006
11/2007
11/2008
12/1993
12/1994
12/1995
12/1996
12/1997
12/1998
12/1999
12/2000
12/2001
12/2002
12/2003
12/2004
12/2005
12/2006
12/2007
12/2008
2/1993
2/1994
2/1995
2/1996
2/1997
2/1998
2/1999
2/2000
2/2001
2/2002
Stage
(Monthly
Average), ft
9.256109903
9.204682367
9.252407367
10.12897557
11.46371007
9.686492065
8.642649155
9.564827527
9.011538443
10.81663219
18.43942204
10.5440784
12.71645545
9.396083596
9.871145873
9.705613003
9.590282258
9.078978495
9.16797043
11.5916129
11.18869176
9.407858692
8.840938406
11.39564312
10.09746413
15.13840941
18.48413974
28.67995924
26.21015157
18.05592715
14.63628942
10.8197422
9.550381082
MonthYear
2/2003
2/2004
2/2005
2/2006
2/2007
2/2008
3/1993
3/1994
3/1995
3/1996
3/1997
3/1998
3/1999
3/2000
3/2001
3/2002
3/2003
3/2004
3/2005
3/2006
3/2007
3/2008
4/1993
4/1994
4/1995
4/1996
4/1997
4/1998
4/1999
4/2000
4/2001
4/2002
4/2003
Stage
(Monthly
Average), ft
9.504345238
9.845431659
13.13287202
14.52883929
11.13914966
10.73221134
10.84727199
10.41498951
20.08869474
21.17056786
19.51448453
22.9156212
15.44999281
18.51319308
11.19507539
9.833974138
9.901263547
11.14010811
14.98947092
18.34622312
11.07209677
10.33810484
11.90214553
9.828344843
23.92011811
15.72280307
14.25320986
24.27294444
13.90497272
13.39182502
10.83327899
10.31426027
10.35948478
68
Continued Table
MonthYear
4/2004
4/2005
4/2006
4/2007
4/2008
2/2003
2/2004
2/2005
5/1993
5/1996
5/1997
5/1998
5/1999
5/2000
5/2001
5/2002
5/2003
5/2004
5/2005
5/2006
5/2007
5/2008
6/1993
6/1994
6/1995
6/1996
6/1997
6/1998
6/1999
6/2000
6/2001
6/2002
6/2003
Stage
(Monthly
Average), ft
10.48908152
16.94904046
26.68501433
10.63078744
10.65124802
9.504345238
9.845431659
13.13287202
11.98308476
16.63667856
13.76774815
22.38389259
13.19436603
12.93101281
11.38210332
10.54971652
10.32199392
10.38443841
17.30332983
26.34927361
11.45799358
11.04971891
10.51243568
8.631145246
20.53095109
12.60432515
11.70438889
22.41919296
10.85321153
10.86236336
9.186522947
8.938483696
9.799964976
MonthYear
6/2004
6/2005
6/2006
6/2007
6/2008
7/1993
7/1994
7/1995
7/1996
7/1997
7/1998
7/1999
7/2000
7/2001
7/2002
7/2003
7/2004
7/2005
7/2006
7/2007
7/2008
8/1993
8/1994
8/1995
8/1996
8/1997
8/1998
8/1999
8/2000
8/2001
8/2002
8/2003
8/2004
Stage
(Monthly
Average), ft
8.948094807
17.06044444
21.63152995
10.37854003
8.537793358
9.363877741
8.68269969
18.12811145
10.74940451
10.63876179
19.89726785
10.10844979
9.918919737
8.921653226
8.715054348
8.785745676
8.536112085
12.83185484
14.05137242
10.14942181
8.200510753
10.10448356
8.29080446
13.12745627
10.56357362
10.55262511
14.29552419
9.915749569
10.19267648
8.821406615
8.502081073
8.717146447
8.514045699
69
Continued Table
MonthYear
8/2005
8/2006
8/2007
8/2008
9/1993
9/1994
9/1995
9/1996
9/1997
9/1998
9/1999
9/2000
9/2001
9/2002
9/2003
9/2004
9/2005
9/2006
9/2007
9/2008
Stage
(Monthly
Average), ft
11.33034771
13.02441195
10.31826894
8.230085237
11.12444698
8.286662853
13.44601028
10.67441908
10.57591107
14.2491815
9.951892779
10.34393901
8.885111111
8.522282499
8.705879831
8.499119444
10.93700604
12.58439476
9.259441363
8.075402778
Calculation of Summer Mean
Month/Year
Stage, ft
8/1993
8/1994
8/1995
8/1996
8/1997
8/1998
8/1999
8/2000
8/2001
8/2002
8/2003
8/2004
8/2005
8/2006
8/2007
8/2008
10.10448356
8.29080446
13.12745627
10.56357362
10.55262511
14.29552419
9.915749569
10.19267648
8.821406615
8.502081073
8.717146447
8.514045699
11.33034771
13.02441195
10.31826894
8.230085237
Summer
(August
Mean)
10.28129293
Summer Mean WSE (NGVD 1988) = 10.3 + 2.4 = 12.7 ft
70
APPENDIX D
HEC-RAS Output
71
Figure D.1 – Cross-Section with Repair on Existing System with 100-Year Water Surface
Elevation (From River Station 71.66 to 71.625)
72
Figure D.2 – Cross-Section with Repair on Existing System with 100-Year Water Surface
Elevation (From River Station 71.451 to 71.35)
73
APPENDIX E
Compact Disk (CD) – HEC-RAS Model
74
REFERENCES
1.
U.S. Army Corps of Engineers (1991/1994). Engineering Manual 1110-2-1601:
Hydraulic Design of Flood Control Channel. U.S. Army Corps of Engineers,
Washington, DC 20314-1000.
2.
U.S. Army Corps of Engineers (2000). Engineering Manual 1110-2-1913:Design
and Construction of Levees. U.S. Army Corps of Engineers, Washington, DC
20314-1000.
3.
U.S. Army Corps of Engineers (1990). Engineering Manual 1110-22302:Construction with Large Stone. U.S. Army Corps of Engineers,
Washington, DC 20314-1000.
4.
Dr. Robert L. Barkau (2001). User’s Manual: UNET – One-Dimensional
Unsteady Flow Through a Full Network of Open Channels. U.S. Army Corps of
Engineers, 609 Second Street, Davis, CA 95616-4687.
5.
Gary W. Brunner (2010). HEC-RAS, River Analysis System Hydraulic Reference
Manual. U.S. Army Corps of Engineers, 609 Second Street, Davis, CA 956164687.
75
6.
Stephen T. Maynord, Martin T. Hebler, Sheila F. Knight (1998). User’s Manual
for CHANLPRO, PC Program for Channel Protection Design. U.S. Army Corps
of Engineers, 3909 Halls Ferry Road, Vicksburg, MS 39180-6199.
7.
Ven T Chow (1973). Open-Channel Hydraulics. McGraw-Hill Book Company.