OFFICE OF THE CHIEF OF ENGINEERS
VALUE ENGINEERING STUDY TEAM
US Army Corps
of Engineers
VALUE ENGINEERING STUDY SUMMARY REPORT
MATILIJA DAM REMOVAL AND
ECOSYSTEM RESTORATION PROJECT
VENTURA COUNTY, CALIFORNIA
Sponsored By: The U.S. Army
Engineering District, Los Angeles
September 2007
VALUE ENGINEERING TEAM STUDY
DOD SERVICE: USACE
VALUE ENGINEERING OFFICER: Bob Conley
Value Engineering Study Report on
MATILIJA DAM REMOVAL AND
ECOSYSTEM RESTORATION PROJECT
VENTURA COUNTY, CALIFORNIA
SEPTEMBER 2007
Sponsor:
The U.S. Army Engineering District, Los Angeles
VALUE ENGINEERING FIRM NAME:
Office of the Chief of Engineers
Value Engineering Study Team (OVEST)
ADDRESS: 69A Hagood Avenue
Charleston, SC
29403-5107
PHONE:
(843) 329-8063
VALUE ENGINEERING STUDY TEAM LEADER: Rick Lambert, PE, CVS
(843) 329-8063
VALUE ENGINEERING STUDY TEAM MEMBERS
Bill Easley - OVEST
John Mathis – OVEST
Jim Henderson - CESAW
Brad Bird - CENWP
Bruce Henderson – CESPL
1
VALUE ENGINEERING TEAM STUDY
TABLE OF CONTENTS
Page No.
Cover................................................................................................................................. 1
Table of Contents ............................................................................................................. 2
Project Description and Background ................................................................................ 4
Vicinity and Locality Map .................................................................................................. 6
Project Plan ...................................................................................................................... 7
Executive Summary ......................................................................................................... 8
Summary of Recommendations ....................................................................................... 9
Proposals:
1 Use geotubes in lieu of soil-cement
........................................................................ 11
2 Use conveyor to transport sediment in lieu of slurry
............................................... 14
3 Optimize hydraulic placement of all materials; remove delta materials
first from the new 100’ wide stream alignment. This provides for more
lake water storage for future slurry removal of silts from behind the dam
4 Recycle concrete on site
............. 17
...................................................................................... 21
5 Use temporary reservoirs to increase water supply for single season for slurry
6 Do not remove entire dam, leave part of the abutments
.......................................... 25
7 Bury vegetation burial in sediment storage sites in lieu of removal
8 Recover water from slurry downstream and
pump it back upstream in lieu of buying water
9
2
......................... 28
....................................................... 29
Overexcavate slurry disposal site and mix silt with reserved
in-situ material to facilitate revegetation and post project uses
10 Mix in silts with sands for disposal upstream to
facilitate revegetation of upstream disposal sites
...... 23
............................. 37
............................................... 41
VALUE ENGINEERING TEAM STUDY
TABLE OF CONTENTS
Page No.
Value Engineering Comments ........................................................................................... 43
Supporting Documents ...................................................................................................... 52
Appendix A: Contact Directory ......................................................................................... 53
Appendix B: Function Analysis System Technique (FAST) Diagram ............................... 56
Appendix C: Cost Model .................................................................................................. 58
Appendix D: Speculation List .......................................................................................... 60
3
VALUE ENGINEERING TEAM STUDY
PROJECT DESCRIPTION AND BACKGROUND
PROJECT TITLE:
Matilija Dam Removal and Ecosystem Restoration Project
PROJECT LOCATION:
Ventura County, California
General. The purpose of the proposed Matilija Dam Removal and Ecosystem
Restoration project is to restore aquatic and terrestrial habitat along Matilija Creek and
the Ventura River through the restoration of hydrologic and sediment transport riverine
and coastal processes, and enhance recreational opportunities along Matilija Creek and
the Ventura River consistent with ecosystem recovery objectives. The project
comprises the removal of the dam and accumulated sediments upstream of the dam,
transport of the sediment to permanent and temporary storage areas, modification of
the Robles Diversion Dam to protect water quality, modification of two levees and
construction of one new levee to protect downstream communities, removal and/or
relocation of two bridge crossings to convey anticipated increased quantities of runoff
and sediment, and restoration of aquatic and terrestrial habitats to benefit native fish
and wildlife, including the removal of the invasive non-native giant reed (Arundo donax).
Location. The Ventura River and Matilija Creek watersheds are located in
northwestern Ventura County in southern California. Matilija Creek is a tributary to the
Ventura River. On Matilija Creek, the action area begins approximately 1.5 miles
upstream of the dam and extends 0.6 miles downstream to the confluence with the
Ventura River (North Fork Matilija Creek). On the Ventura River, the action area
extends from the confluence with Matilija Creek downstream approximately 15.5 miles
to the estuary at the Pacific Ocean.
History. Activities on the Ventura River watershed, including construction of Matilija
Dam and Casitas Dam, adversely affected riverine processes and habitat values. Since
the completion of the Matilija Dam in 1948, diminished sediment transport through the
watershed resulted in stream downcutting and beach erosion. Structural integrity of the
dam was adversely affected by use of inappropriate materials and notching to lower the
effective height was conducted on two occasions. Entrapment of sediment upstream of
Matilija Dam rendered the dam inoperable within two decades of construction. Other
anthropogenic factors, such as agricultural activities and urbanization and their
necessary water withdrawals from the watershed, resulted in severely diminished
habitat values, particularly for aquatic species such as California red-legged frog and
steelhead, federally listed as threatened and endangered, respectively. Construction of
the dams also prevented access by steelhead to very productive spawning and rearing
habitat.
4
VALUE ENGINEERING TEAM STUDY
PROJECT DESCRIPTION AND BACKGROUND
PROJECT TITLE:
Matilija Dam Removal and Ecosystem Restoration Project
PROJECT LOCATION:
Ventura County, California
The Matilija Dam Removal and Ecosystem Restoration Project includes dredging in the
reservoir behind the dam and transport of sediment downstream by slurry pipeline,
demolishing and removing the existing concrete arch dam, channel excavation and
placing soil materials in disposal areas upstream from the dam. Two bridge
replacements are included. Eradication of the invasive exotic plant species Arundo
Donax (Giant Reed) is also included in the work.
The total project cost for the recommended plan is currently estimated to be
$123,777,000.
Also see Supporting Documents Appendices for project Cost Model and the Function
Analysis System Technique (FAST) diagram, a logic diagram identifying project critical
functions.
5
VALUE ENGINEERING TEAM STUDY
PROJECT DESCRIPTION AND BACKGROUND
PROJECT TITLE:
Matilija Dam Removal and Ecosystem Restoration Project
PROJECT LOCATION:
Ventura County, California
VICINITY AND LOCALITY MAP
(Hwy 50 – Baldwin Rd)
6
VALUE ENGINEERING TEAM STUDY
PROJECT DESCRIPTION AND BACKGROUND
PROJECT TITLE:
Matilija Dam Removal and Ecosystem Restoration Project
PROJECT LOCATION:
Ventura County, California
PROJECT PLAN
7
VALUE ENGINEERING TEAM STUDY
EXECUTIVE SUMMARY
The Value Engineering Study was conducted at the Ventura County Public Works
Department on 17 – 20 September 2007. The study was based on the Matilija Dam
Ecosystem Restoration Feasibility Study Formulation of Alternative Plans for the F4
Milestone Report. The VE team was comprised of members of Los Angeles, Portland,
and Wilmington Districts and OVEST (See Appendix A).
Value Engineering (VE) is an organized study of functions to satisfy the users needs
with a quality product at the lowest life cycle cost through applied creativity. VE takes a
critical look at how the various project functions are proposed to be met and identifies
alternative ways to achieve the equivalent function while increasing the value of
benefits. In the end, it is hoped that the project will realize a reduction in cost, but
increased value is the focus of the process. The project was studied using the Corps of
Engineers standard Value Engineering (VE) methodology, consisting of five phases:
Information Phase: The PDT briefed the VE study team on the project and led a field trip
to the site. Project objectives were identified and discussed to fully understand the work
to be performed. The Function Analysis System Technique (FAST) was used to identify
project functions and a FAST diagram was prepared (see Appendix B). The cost
estimate was reviewed and a Cost Model was developed to determine areas of relative
high cost to ensure that the team focused on those parts of the project that offered the
most potential for cost savings. (see Appendix C).
Speculation Phase: The Team speculated by conducting brainstorming sessions to
generate ideas for alternative designs. All team members contributed ideas and critical
analysis of the ideas was discouraged (see Appendix D).
Analysis Phase: Evaluation, testing and critical analysis of all ideas generated during
speculation was performed to determine potential for savings and possibilities for risk.
Ideas that did not survive critical analysis were deleted.
Development Phase: The priority ideas were developed into written proposals by VE
team members during an intensive technical development session. Proposal
descriptions, along with sketches, technical support documentation, and cost estimates
were prepared to support implementation of ideas. Additional VE Team Comments
were included for items of interest that were not developed as proposals, and these
comments follow the study proposals.
Presentation Phase: An informal outbriefing was conducted at the conclusion of the
study to review the proposals. This VE Study Report will be distributed for review to all
appropriate project supporters and decision-makers. Review comments will be
coordinated by the District Value Engineering Officer and Project Manager for decision
on any proposals recommended by the study report.
8
VALUE ENGINEERING TEAM STUDY
SUMMARY OF RECOMMENDATIONS/ACTION
PROPOSAL
NUMBER
DESCRIPTION
POTENTIAL
SAVINGS
1
Use geotubes in lieu of soil-cement
$ 1.76 Million
2
Use conveyor to transport sediment
in lieu of slurry
- $ 2.33 Million
Optimize hydraulic placement of all
materials; remove delta materials
first from the new 100’ wide stream
alignment. This provides for more
lake water storage for future slurry
removal of silts from behind the dam
$ 3.34 Million
4
Recycle concrete on site
$ 2.26 Million
5
Use temporary reservoirs
to increase water supply for
single season for slurry
- $ 400,000
Do not remove entire dam,
leave part of the abutments
$ 1.1 Million
Bury vegetation burial in sediment
storage sites in lieu of removal
$ undetermined
Recover water from slurry
downstream and pump It back
upstream in lieu of buying water
$ 490,000
3
6
7
8
9
RECOMMENED
ACTION
VALUE ENGINEERING TEAM STUDY
SUMMARY OF RECOMMENDATIONS/ACTION
PROPOSAL
NUMBER
DESCRIPTION
9
10
POTENTIAL
SAVINGS
Overexcavate slurry disposal site
and mix silt with reserved in-situ
material to facilitate revegetation
and post project uses
- $ 7 Million
Mix in silts with sands for disposal
upstream to facilitate revegetation
of upstream disposal sites
$ 1.2 Million
RECOMMENED
ACTION
TOTAL CUMULATIVE SAVINGS = $ 10.15 Million
TOTAL CUMULATIVE QUALITY IMPROVEMENTS = $ 9.10 Million
10
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
DESCRIPTION:
1
Use geotubes in lieu of soil-cement
PAGE NO: 1 OF 3
ORIGINAL DESIGN: The recommended plan for Matilija Dam Removal includes using
soil-cement to construct a barrier to contain materials in disposal areas upstream from
the dam. Soil cement is considered to be strong enough to contain material in the
disposal areas, but will decay over time, allowing material to pass downstream more
gradually.
PROPOSED DESIGN: The proposed design would use geotubes for the disposal area
containment structure. The geotextile fabric tubes would be filled with granular material
from the dredge pipeline.
ADVANTAGES:
1. Geotube can be cut open to allow material to escape at prescribed intervals.
2. Eliminates the need to construct a batch plant to produce soil cement mixture.
3. Less material required for stability, saving cost and construction time.
DISADVANTAGES:
1. Geotextile tube would need to be removed at some later date.
2. Aesthetically less attractive than soil cement.
JUSTIFICATION:
Geotube should be considered as an alternate method for creating a barrier to contain
material in the disposal area. These could be filled with dredged material, which would
be much less costly than setting up a batch plant and constructing a soil cement barrier.
Containing the material in a geotextile tube would require less material than would be
required in a soil cement levee structure.
11
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
1
PAGE NO: 2 OF 3
Drawing No. 1
GEOTUBE USED FOR TOE PROTECTION
DISPOSAL
GEOTUBE
GEOTUBE
DISPOSAL
TYPICAL SECTION THRU GEOTUBE CONTAINMENT STRUCTURE
12
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
1
PAGE NO: 3 OF 3
COST ESTIMATE WORKSHEET
Proposal 1
DELETIONS
ITEM
Soil cement wall (5000 LF)
QUANTITY
UNITS
62,900
CY
UNIT COST
$30.00
Total Deletions
TOTAL
$1,887,000
$0
$0
$0
$0
$0
$0
$0
$0
$0
$0
$0
$1,887,000
ADDITIONS
ITEM
Geotube 10' dia - use 2 tubes stacked
Fill for Geotube - 3 CY / LF x 10,000 LF
UNIT COST
$35.00
$10.00
Total Additions
TOTAL
$350,000
$300,000
$0
$0
$0
$0
$0
$0
$0
$0
$0
$0
$650,000
Net Cost Decrease
42.50%
Mark-ups
Total Cost Decrease
$1,237,000
$525,725
$1,762,725
QUANTITY
UNITS
10,000
LF
30,000
CY
Mark-ups include Contingency (25%), Planning, Survey, Engineering and Design (10%)
Engineering During Construction (1%), and Supervision and Administration (6.5%)
13
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
DESCRIPTION:
2
PAGE NO: 1 OF 3
Use conveyor to transport sediment in lieu of slurry
ORIGINAL DESIGN: The ‘Reservoir Area’ sediment, approximately 2.1 million cubic
yards of mostly silt, underlying the existing lake behind Matilija Dam will be slurried to a
designated downstream disposal site, allowing for removal of the dam. Two 12-inch
cutter head suction dredges working 24 hours a day, 7 days a week will be utilized to
slurry the 2.1 million cubic yards of fine sediment in approximately 9 months. Fresh
water from Lake Casitas (4,500 acre-feet) will be used for the slurry media. The slurry
will then pass through a stationary screen to eliminate any coarse material and enter a
thickener. The thickener will be used to increase the solids concentration of the slurry
and recycle water for the dredging operation. A make-up water pump will be required to
pump water back to the dredges. The slurry will then be transported by pipeline to
disposal areas located downstream.
A single 400-horsepower pump will be required at the dam to maintain slurry velocity
in the pipeline. An 8-mile long fresh water pipeline and pumping system will be needed
from Lake Casitas. The fresh water pipeline will be carbon steel and the slurry pipeline
will be high-density polyethylene (HDPE). Additionally, a 90,000-gallon water storage
tank will be placed at the left abutment to provide surge capacity. The thickener
overflow can be fed directly into the storage tank if sufficient elevation difference
between the thickener and storage tank is made available.
Slurried materials will be deposited within several areas in proximity of the Highway
150 (Baldwin Road) Bridge. The areas, comprising 118 acres in the floodplain, are both
upstream and downstream of the bridge and are distant from 3.6 to 6.3 miles
downstream of Matilija Dam. The thickness of the required placement will vary by area
and range between 10 and 25 feet. Earthen containment dikes will be obtained from
required on-site excavation and grading. Slopes on the basin side will be 2h:1V; slopes
on the outside of the basin are assume to be 3H:1V. the heights of the containment
dikes will likely range between 10 and 30 feet, with an average of approximately 20 feet.
Interior dikes will be constructed during slurry placement to enhance stability and
separation of the fines from the water. Following dewatering of the slurried materials,
the return effluent would be permitted to return to stream flow. Prior to placement, the
area will be cleared of vegetation to enhance percolation. Additional features, such as
collection systems, settlement ponds, observation and pumping wells, could be added
to enhance collection of water.
14
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
DESCRIPTION:
2
PAGE NO: 2 OF 3
Use conveyor to transport sediment in lieu of slurry
PROPOSED DESIGN: In lieu of the proposed slurry and pumping system use a
conventional conveyor system to move the 2.1 million cubic yards of ‘Reservoir Area’
sediment downstream to the disposal areas located 3.6 to 6.3 miles downstream. The
conveyor system will allow for mechanical excavation of the material and will not require
the large pumping system from Lake Casitas and the purchasing of the water.
ADVANTAGES:
1. Eliminates the entire cost of the 8 miles of carbon steel pipe from Lake Casitas to the
dam.
2. Eliminates the cost of the 800 HP fresh water pump and electricity costs associated
with pumping against over 500’of head.
3. Eliminates the need for the dredges, the thickener, the flocculent for the thickener
and the high energy costs of operating the slurry system.
4. Eliminates the cost of the slurry pumps.
DISADVANTAGES:
The operation of the proposed alternative is more difficult if significant rainfall occurs
during construction. The material in the reservoir may take extremely long periods of
time to dry adequately to be easily moved by heavy equipment. The initial cost of the
conveyor system is extremely expensive and equipment cost for excavation is
significantly more expensive than with a dredge.
JUSTIFICATION:
Although significant cost savings could occur in some other configurations, the
additional costs outweigh the cost benefits. Specifically, savings in elimination of the
water supply system, to operate it and to buy water from Casitas in addition to the cost
of the sluicing system is still less than the additional cost for excavation of reservoir
materials with conventional means and the installation of a conveyor capable of
handling these materials. Overall cost savings for this alternative is roughly - $1.7
million (negative). This alternative is not recommended however, a more thorough
investigation may pay off if water supply costs and slurry cost estimates go up for any
reason.
15
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
2
PAGE NO: 3 OF 3
COST ESTIMATE WORKSHEET
Proposal 2
DELETIONS
ITEM
9
9.1
9.2
9.3
9.4
9.5
9.6
9.7
9.8
9.9
9.10
10
11
11.1
11.2
11.3
11.4
11.5
11.6
12
13
14
15
16
17
18
19
20
UNITS
Import Water from Casitas
Cost of Water
Pipeline Corridor Preparation (24ftx22,000ft)
Real Estate for ROW
Fresh Water Supply Pumps, 800 HP Each, Goulds Vertical Turbines, in Paralle
Power to Pumps from Casitas for 9 Months
Fresh Water Pipeline, 8 Miles Long, 24"x.357" Wall, A53 Cast Iro
Water Storage Tank, 90,000 Gal, 25ftx25ft Carbon Stee
Makeup Water Pumps, 900 HP Each, Goulds Centrifugals, in Series
Makeup Waterline, 1 Mile Long, 24"x.357" Wall, A53 Cast Iro
Power for Makeup System for 9 Months
12" Cutter Head Suction Dredge, 9 Months Continuou
Slurry System
Pipeline Corridor Preparation (24ftx18,000ft
Real Estate for ROW
Thickener, 115' Diameter, incl. Flocculant Package, 40 HP Rake Moto
Slurry Pipeline, 7.85 Miles Long, 20" SRD 11, HDPE Pipe, 16.146" ID
Slurry Pumps, 1,200 HP Each, Warman Slurry Pumps in Series
Power for Slurry System for 9 Months
Operation Crew: 4 Operators, 1 Technician, 24hrs x 270 day
Clear disposal area
Construct containment dikes (excavation, place & compact in disposal area
Misc. detail at dikes (drainage, grading, imported stone 4600cy
Dust Abatement
Real Estate for Disposal of Fines
Site Restoration
Road Repair
Disposal Site Closure
QUANTITY
UNIT COST
ACR-FT
SF
ACR
EA
KW-HRS
LF
EA
EA
LF
KW-HRS
EA
4,500
$177.00
648,000
$1.00
0
$17,000.00
1
$106,000.00
3,900,000
$0.15
42,240
$15.00
1
$110,000.00
3
$94,000.00
5,280
$25.00
13,053,000
$0.15
2 $2,700,000.00
SF
ACR
EA
LF
EA
KW-HRS
MAN-HRS
ACR
CY
LS
LS
ACR
LS
MILE
LS
432,000
$1.00
10
$17,000.00
1
$900,000.00
41,470
$24.00
1
$75,000.00
1,934,000
$0.15
26,000
$50.00
94
$3,000.00
416,000
$5.00
1
$700,000.00
1
$135,000.00
118
$2,500.00
1 $1,077,500.00
2
$50,000.00
1
$200,000
Total Deletions
TOTAL
$0
$796,500
$648,000
$0
$106,000
$585,000
$633,600
$110,000
$282,000
$132,000
$1,957,950
$5,400,000
$0
$432,000
$170,000
$900,000
$995,280
$75,000
$290,100
$1,300,000
$282,000
$2,080,000
$700,000
$135,000
$295,000
$1,077,500
$100,000
$200,000
$19,682,930
ADDITIONS
ITEM
9
9.1
9.2
9.3
9.4
9.5
9.6
9.7
9.8
9.9
9.10
10
11
11.1
11.2
11.3
11.4
11.5
11.6
12
13
14
15
16
17
18
19
20
UNITS
Import Water from Casitas
Cost of Water
Pipeline Corridor Preparation (24ftx22,000ft)
Real Estate for ROW
Fresh Water Supply Pumps, 800 HP Each, Goulds Vertical Turbines, in Paralle
Power to Pumps from Casitas for 9 Months
Fresh Water Pipeline, 8 Miles Long, 24"x.357" Wall, A53 Cast Iro
Water Storage Tank, 90,000 Gal, 25ftx25ft Carbon Stee
Makeup Water Pumps, 900 HP Each, Goulds Centrifugals, in Series
Makeup Waterline, 1 Mile Long, 24"x.357" Wall, A53 Cast Iro
Power for Makeup System for 9 Months
12" Cutter Head Suction Dredge, 9 Months Continuou
Slurry System
Pipeline Corridor Preparation (24ftx18,000ft
Real Estate for ROW
Thickener, 115' Diameter, incl. Flocculant Package, 40 HP Rake Moto
Slurry Pipeline, 7.85 Miles Long, 20" SRD 11, HDPE Pipe, 16.146" ID
Slurry Pumps, 1,200 HP Each, Warman Slurry Pumps in Series
Power for Slurry System for 9 Months
Operation Crew: 4 Operators, 1 Technician, 24hrs x 270 day
Clear disposal area
Construct containment dikes (excavation, place & compact in disposal area
Misc. detail at dikes (drainage, grading, imported stone 4600cy
Dust Abatement
Real Estate for Disposal of Fines
Site Restoration
Road Repair
Disposal Site Closure
Excavation/loading
Conveyor system
Earth moving equipment to load conveyor
Operation crew: 4 operators, 1 technician, 24 hrs x270 day
Power for conveyor system for 9 months
ACR-FT
SF
ACR
EA
KW-HRS
LF
EA
EA
LF
KW-HRS
EA
SF
ACR
EA
LF
EA
KW-HRS
MAN-HRS
ACR
CY
LS
LS
ACR
LS
MILE
LS
CY
mi
man-hrs
kw-hrs
QUANTITY
UNIT COST
0
$177.00
0
$1.00
0
$17,000.00
0
$106,000.00
0
$0.15
0
$15.00
0
$110,000.00
0
$94,000.00
0
$25.00
0
$0.15
0 $2,700,000.00
432,000
$1.00
10
$17,000.00
0
$900,000.00
0
$24.00
0
$75,000.00
0
$0.15
26,000
$50.00
94
$3,000.00
416,000
$5.00
1
$700,000.00
1
$135,000.00
118
$2,500.00
1 $1,077,500.00
2
$50,000.00
1
$200,000
2100000
$2.50
7.85
1,000,000
26000
967000
Total Additions
50
0.15
Net Cost Decrease
Mark-ups
42.50%
Total Cost Decrease
Mark-ups include Contingency (25%), Planning, Survey, Engineering and Design (10%)
Engineering During Construction (1%), and Supervision and Administration (6.5%)
16
TOTAL
$0
$0
$0
$0
$0
$0
$0
$0
$0
$0
$0
$0
$0
$432,000
$170,000
$0
$0
$0
$0
$1,300,000
$282,000
$2,080,000
$700,000
$135,000
$295,000
$1,077,500
$100,000
$200,000
$5,250,000
$7,850,000
$0
$1,300,000
$145,050
$21,316,550
-$1,633,620
-$694,289
-$2,327,909
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
DESCRIPTION:
3
PAGE NO: 1 OF 3
Optimize hydraulic placement of all materials; remove delta
materials first from the new 100’ wide stream alignment.
This provides for more lake water storage for future slurry removal
of silts from behind the dam.
ORIGINAL DESIGN:
The current plan proposes to perform a disposal site closure operation, constructing soil
cement containment embankments and then constructing a 100’ wide new channel
alignment utilizing conventional earth moving equipment.
PROPOSED DESIGN:
The proposed plan is to construct the containment embankments and disposal sites
with construction techniques which utilize a portable hydraulic dredge to excavate and
place materials from the new 100’ wide channel.
ADVANTAGES:
1.
2.
3.
4.
5.
Reduces construction labor, equipment and duration.
Eliminates or reduces the dewatering requirements.
Provides for higher capacity of water storage for future slurry transport.
Additional water required to be purchased will be greatly reduced.
Segregates a good bit of clays and silts from upstream materials which would now
be included with the materials to be bypassing the Robles Diversion Dam during
slurry disposal.
DISADVANTAGES:
1. Water quality will be turbid to a greater extent.
2. Channel side slope will be flatter – say 4 to 1 vs. 3 to 1 as originally designed slightly
increasing quantities to be excavated and placed in disposal areas.
3. Constructing soil cement embankment may be more difficult to construct. (Assumed
some quantity to be replaced by geotextile filled tubes as a cost benefit – see
proposal #1 and this cost estimate).
4. Disposal site alignment may need to be altered or relocated to facilitate required
capacities. (Material may be more difficult to contain if material can’t be highly
sloped or easily moved within the designated areas).
17
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
DESCRIPTION:
3
PAGE NO: 1 OF 3
Optimize hydraulic placement of all materials; remove delta
materials first from the new 100’ wide stream alignment.
This provides for more lake water storage for future slurry removal
of silts from behind the dam.
JUSTIFICATION:
There is potential for significant savings of first cost and construction duration with no
significant risk increase.
18
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
3
PAGE NO: 2 OF 3
Drawing No. 1
TYPICAL SECTION
19
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
3
PAGE NO: 3 OF 3
COST ESTIMATE WORKSHEET
PROPOSAL NO.: Matilija # 3 - Optimize hydraulic placement of materials upstream of dam.
DELETIONS
ITEM
Dewatering (assumed cost used for closure)
UNITS
job
QUANTITY
1
UNIT COST
lump sum
TOTAL
$200,000
Soil Cement Wall (assumed 50% - 2500lf)
cy
31,450
$30.00
$943,500
Channel Excavation (conventional equipment)
cy
1,113,000
$3.00
$3,339,000
Total Deletions
$4,482,500
UNITS
cy
QUANTITY
15,000
UNIT COST
$50.00
TOTAL
$750,000
cy
1,113,000
$1.25
$1,391,250
ADDITIONS
ITEM
Geotextile Tubes (assumed 7' average height)
Channel Excavation (hydraulic equipment)
Total Additions
Net Savings
Markups
Total Savings
20
$2,141,250
42.50%
$2,341,250
$995,031
$3,336,281
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
DESCRIPTION:
4
Recycle concrete on site
PAGE NO: 1 OF 2
ORIGINAL DESIGN:
Matilija Dam, a 190-foot high thin arch concrete structure located about 16 miles from
the Pacific Ocean in Ventura County, California is proposed to be demolished and
removed. The present design calls for concrete debris to be loaded and hauled to a
concrete recycling plant located approximately 28 miles away from the project site.
PROPOSED DESIGN:
The proposed design would recycle the concrete debris from the removal of the Matilija
Dam on or near the project site. Hauling distance for concrete debris would be reduced
to approximately 4 miles maximum.
ADVANTAGES:
1. Eliminates hauling of concrete to the Recycling Plant
2. Reduces the overall cost of the project
DISADVANTAGES:
1. The contractor would have to haul and place the concrete locally on site
JUSTIFICATION:
Hauling costs could be reduced if uses for recycled concrete can be found closer to the
project site. Concrete rubble could be processed into riprap size material for
streambank erosion control or into roadway base material.
21
VALUE ENGINEERING PROPOSAL
PROPOSAL NO: 4
PAGE NO: 2 OF 2
COST ESTIMATE WORKSHEET
Proposal 4
DELETIONS
ITEM
Haul Concrete to Recycling Plant 28 mi
QUANTITY
UNITS
51,100
CY
UNIT COST
$36.00
Total Deletions
TOTAL
$1,839,600
$0
$0
$0
$0
$0
$0
$0
$0
$0
$0
$0
$1,839,600
ADDITIONS
ITEM
Haul Concrete Locally 5 mi
UNIT COST
$5.00
Total Additions
TOTAL
$255,500
$0
$0
$0
$0
$0
$0
$0
$0
$0
$0
$0
$255,500
Net Cost Decrease
42.50%
Mark-ups
Total Cost Decrease
$1,584,100
$673,243
$2,257,343
QUANTITY
UNITS
51,100
CY
Mark-ups include Contingency (25%), Planning, Survey, Engineering and Design (10%)
Engineering During Construction (1%), and Supervision and Administration (6.5%)
22
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
DESCRIPTION:
5
PAGE NO: 1 OF 2
Use temporary reservoirs to increase water supply
for single season for slurry
ORIGINAL DESIGN: Fresh water from Lake Casitas (4,500 acre-feet) will be used for
the slurry media. An 8-mile long fresh water pipeline and pumping system will be
needed to supply this water from Lake Casitas. The fresh water pipeline will be carbon
steel and will be 24” in diameter and be powered by a single 800 hp pump and three
900 hp pumps operating in series. Additionally, a 90,000-gallon water storage tank will
be placed at the left abutment to provide surge capacity. Additional features, such as
collection systems, settlement ponds, observation and pumping wells, could be added
to enhance collection of water.
PROPOSED DESIGN: Place temporary reservoirs upstream of Matilija dam to capture
and store water to aid in slurry operations. Reservoirs would have to be placed above
the areas of excavation in the delta to not interfere with construction. As a result the
reservoirs would be limited in size to be within the upper floodplain, but out of the low
flow channel. It would be reasonable to have two reservoirs of approximately 5 and 3
acres resulting in a total volume of approximately 40 acre-ft and 18 acre-feet for a total
of 58 acre-feet of temporary storage.
ADVANTAGES: Reduces the amount of water that must be purchased from Casitas
and reduces the cost of pumping of 58 acre-feet.
DISADVANTAGES: Increases construction cost to build and maintain the two
reservoirs for just one season. This alternative does not reduce the cost of pumps,
pipeline and right of way for add in water. There is very little reduction in purchase of
water of 58 acre-feet or less than 1.3% of the water purchased.
JUSTIFICATION: The significant amount of additional engineering, construction costs
and environmental concerns associated with this alternative with only a marginal
reduction in cost and an actual increase in construction costs makes this alternative not
recommended. The additional cost of the materials for the reservoirs is $400,000 more
than the benefits.
23
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
5
PAGE NO: 2 OF 2
Original Design
9
9.1
9.2
9.3
9.4
9.5
9.6
9.7
9.8
9.9
9.10
Import Water from Casitas
Cost of Water
Pipeline Corridor Preparation (24ftx22,000ft)
Real Estate for ROW
Fresh Water Supply Pumps, 800 HP Each, Goulds Vertical Turbines, in Paralle
Power to Pumps from Casitas for 9 Months
Fresh Water Pipeline, 8 Miles Long, 24"x.357" Wall, A53 Cast Iro
Water Storage Tank, 90,000 Gal, 25ftx25ft Carbon Stee
Makeup Water Pumps, 900 HP Each, Goulds Centrifugals, in Series
Makeup Waterline, 1 Mile Long, 24"x.357" Wall, A53 Cast Iro
Power for Makeup System for 9 Months
4,500
648,000
0
1
3,900,000
42,240
1
3
5,280
13,053,000
ACR-FT
SF
ACR
EA
KW-HRS
LF
EA
EA
LF
KW-HRS
$177.00
$1.00
$17,000.00
$106,000.00
$0.15
$15.00
$110,000.00
$94,000.00
$25.00
$0.15
Subtotal
$796,500
$648,000
$0
$106,000
$585,000
$633,600
$110,000
$282,000
$132,000
$1,957,950
$5,251,050
9
9.1
9.2
9.3
9.4
9.5
9.6
9.7
9.8
9.9
9.10
Import Water from Casitas
Cost of Water
Pipeline Corridor Preparation (24ftx22,000ft)
Real Estate for ROW
Fresh Water Supply Pumps, 800 HP Each, Goulds Vertical Turbines, in Paralle
Power to Pumps from Casitas for 9 Months
Fresh Water Pipeline, 8 Miles Long, 24"x.357" Wall, A53 Cast Iro
Water Storage Tank, 90,000 Gal, 25ftx25ft Carbon Stee
Makeup Water Pumps, 900 HP Each, Goulds Centrifugals, in Series
Makeup Waterline, 1 Mile Long, 24"x.357" Wall, A53 Cast Iron
Power for Makeup System for 9 Months
4,452
648,000
0
1
3,858,400
42,240
1
3
5,280
13,053,000
ACR-FT
SF
ACR
EA
KW-HRS
LF
EA
EA
LF
KW-HRS
$177.00
$1.00
$17,000.00
$106,000.00
$0.15
$15.00
$110,000.00
$94,000.00
$25.00
$0.15
Subtotal
$788,004
$648,000
$0
$106,000
$578,760
$633,600
$110,000
$282,000
$132,000
$1,957,950
$5,236,314
$5
$414,500
Proposed Design
Temporary Reservoir material
Excavate/place material for temporary dams
82900 CY
Cost savings
($399,764)
24
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
DESCRIPTION:
6
PAGE NO: 1 OF 3
Do not remove entire dam. Leave part of the abutments
ORIGINAL DESIGN:
The present design proposes to remove the entire existing concrete arch dam and
associated structures flush with the original rock bottom and sides.
PROPOSED DESIGN:
The proposed design would remove most of the existing concrete arch dam. A small
portion of the dam at the abutments, say 20 feet wide max on each side, would be left in
place.
ADVANTAGES:
Leaving a portion of the existing dam would save some cost and time that would have
been expended to demolish the entire dam.
Preserves a small portion of the dam for historical record.
DISADVANTAGES:
Concrete abutments left in place would detract from the project objective of restoring the
river to its original appearance.
Leaving the concrete could present an attractive nuisance and leave the potential for a
liability claim.
JUSTIFICATION:
Concrete demolition is expensive. If some of the demolition can be avoided while
providing the same function, substantial savings can be achieved. Rather than
completely erasing the dam from history, leaving a small portion would be a reminder
for future generations.
25
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
6
PAGE NO: 2 OF 3
Drawing No. 1
DAM ELEVATION SKETCH
20’
20’
CUT BACK DAM TO
WITHIN 20’ OF ROCK
SIDE SLOPES AND
LEAVE REMAINDER
OF ABUTMENTS
DAM CROSS SECTION SKETCH
Concrete volume saved by leaving the abutments:
(15+50)/2 avg width x 160’ high = 5200 SF x 10’ avg width x 2 abutments / 27 = 3,852 CY
Abutment Percentage of total dam removal:
3,852 CY / (51,110 + 70 + 120 CY) = 7.5%
26
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
6
PAGE NO: 3 OF 3
COST ESTIMATE WORKSHEET
Proposal 6
DELETIONS
ITEM
Quantities in cost estimate
reduced by 7.5%:
Excavate Concrete Dam
Blasting Horizontal Rows
Drilling Horizontal Holes
Blasting Vertical Holes
Drilling Vertical Holes
Process Concrete for Hauling
Haul Concrete to Recycling Plant
Remove & Dispose Misc Metal Work
UNITS
QUANTITY
UNIT COST
$36.00
$18.00
$28.00
$19.00
$23.00
$2.00
$25.00
$2.50
3,833
716
9,330
570
9,150
723
5,421
3,488
CY
EA
LF
EA
LF
CY
CY
LB
Total Deletions
TOTAL
$137,970
$12,893
$261,240
$10,830
$210,450
$1,446
$135,534
$8,721
$0
$0
$779,084
ADDITIONS
ITEM
UNITS
QUANTITY
UNIT COST
Total Additions
Net Cost Decrease
42.50%
Mark-ups
Total Cost Decrease
Mark-ups include Contingency (25%), Planning, Survey, Engineering and Design (10%)
Engineering During Construction (1%), and Supervision and Administration (6.5%)
27
TOTAL
$0
$0
$0
$0
$0
$0
$0
$0
$0
$0
$0
$0
$0
$779,084
$331,111
$1,110,194
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
DESCRIPTION:
7
PAGE NO: 1 OF 1
Bury vegetation in sediment storage sites in lieu of removal
ORIGINAL DESIGN:
Original design identified specific areas upstream of the dam for deposition of
excavated fine sediments. These areas are heavily vegetated, primarily with the
invasive non-native giant reed (Arundo donax) and native willow species (Salix spp.),
with the occasional Fremont cottonwood (Populus fremontii) and western sycamore
(Platanus racemosa). Original design calls for physical removal of existing vegetation
prior to deposition of excavated material at a cost of $10,000 per acre.
PROPOSED DESIGN:
Burial of vegetation in situ with excavated sediments. May require knocking down
existing vegetation prior to deposition of excavated sediments.
ADVANTAGES:
Eliminates the need to remove the considerable amount of existing vegetation by
cutting, chipping and hauling of vegetation residue to eventual disposal site. Would
save an estimated $10,000 per acre.
DISADVANTAGES:
May not be successful at removing Arundo in the sediment disposal areas. Arundo is
notorious for sprouting from buried rhizomes or nodes on the stems, unless the material
is sufficiently dessicated. It is unknown at which burial depth Arundo cannot resprout,
but a study conducted on the Santa Margarita River in San Diego County in 1996
included an investigation of Arundo rhizome resprout from buried depths of 10, 50 and
100 cm. This study found that 50-60 percent of the Arundo rhizomes successfully
sprouted from all three depths with a greater average growth rate from the samples
buried at 100 cm. No other information was found regarding burial at greater depths. If
the proposed design were to be followed and Arundo resprouted, foliar applications of
an appropriate herbicide could be the only feasible option unless funding allowed for
physical removal of the species through the newly placed sediment.
JUSTIFICATION:
Could result in a cost savings estimated at $10,000 per acre as well as shortening the
project by the number of days estimated for site preparation. With X acres estimated
within the proposed project areas, this modification could result in a project savings of
$X.XX.
28
PROPOSAL NO:
DESCRIPTION:
VALUE ENGINEERING PROPOSAL
8
Recover water from slurry downstream and
pump It back upstream in lieu of buying water
PAGE NO: 1 OF 8
ORIGINAL DESIGN (Narration taken from Recommended Plan):
Current design calls for the use of two 12-inch cutter head suction dredges working
around the clock, 24/7 for approximately nine months to slurry 2.1 million cubic yards of
fine sediment from the upstream side of Matilija Dam to disposal sites. In addition to the
water currently impounded behind the dam, 4,500 acre-feet is expected to be pumped
from Lake Casitas to mix the slurry media.
The slurry will then pass through a stationary screen to eliminate any coarse material
and enter a thickener. The thickener will be used to increase the solids concentration of
the slurry and recycle water for the dredging operation. A make-up water pump will be
required to pump water back to the dredges. The slurry will then be transported by
pipeline to disposal areas located downstream.
A single 400-horsepower pump will be required at the dam to maintain slurry velocity in
the pipeline. An 8-mile long fresh water pipeline and pumping system will be needed
from Lake Casitas. The fresh water pipeline will be carbon steel and the slurry pipeline
will be high-density polyethylene (HDPE). Additionally, a 90,000-gallon water storage
tank will be placed at the left abutment to provide surge capacity. The thickener
overflow can be fed directly into the storage tank if sufficient elevation difference
between the thickener and storage tank is made available. Slurried materials will be
deposited within several areas in proximity of the Highway 150 (Baldwin Road) Bridge.
The areas, comprising 118 acres in the floodplain, are both upstream and downstream
of the bridge and are distant from 3.6 to 6.3 miles downstream of Matilija Dam. The
expected path of the slurry lines would follow the river, as shown on Figure 1 below.
The locations of the slurry disposal areas are shown in Figure 2. The thickness of the
required placement will vary by area and range between 10 and 25 feet. Earthen
containment dikes will be constructed to contain the slurried materials. The dikes will be
constructed of sands and gravels obtained from required on-site excavation and
grading. Slopes on the basin side will be 2H: 1V; slopes on the outside of the basin are
assumed to be 3H: 1V. The heights of the containment dikes will likely range between
10 and 30 feet, with an average of approximately 20 feet. Interior dikes will be
constructed during slurry placement to enhance stability and separation of the fines
from the water. Following dewatering of the slurried materials, the return effluent would
be permitted to return to stream flow. Prior to placement, the area will be cleared of
vegetation to enhance percolation. Additional features, such as collection systems,
29
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
8
PAGE NO: 2 OF 8
settlement ponds, observation and pumping wells, could be added to enhance collection
of water.
For the upstream-most slurry disposal site located just north of the Highway 150 Bridge,
slope protection will be required and will consist of riprap stone of approximately 2-foot
diameter, imported from a local quarry located in the vicinity of the damsite. The stone
will be placed on the outside dike slopes to an elevation that will provide a 5- to 10- year
level of protection. The three other disposal areas, downstream of the bridge, are
located mostly on low floodplain terraces and would be subjected to less frequent flows.
Stone protection for these areas to a limited height may consist of boulders obtained
from excavation activities for the construction of the dikes. Willows may also be planted
on the side slopes to provide soil stabilization during larger storm events. Once the
slurried materials are sufficiently dewatered, the disposal areas can be revegetated
using native plants.
PROPOSED DESIGN:
A couple of different methods were suggested to recover water from slurry disposal
downstream in order to pump it back upstream and reduce the costs of buying water
form Lake Casitas. One is to simply collect drainage from slurry as it is spread; the
other is to physically remove excess water from the slurry before spreading.
Prior to slurry operations, grade the slurry disposal areas downstream to drain to
collection ditches, and place perforated drainage pipes with filter cloth sized to prevent
fines from entering the pipes. The collection ditches would convey water by gravity to a
collection point from which it could be pumped back to the reservoir behind Matilija
Dam. Depending on the water losses due to infiltration and evaporation, the collection
ditches could be lined and/or covered; the necessity for this would be determined further
in the design process. For purposes of this analysis, it will be assumed that only 10% of
slurry mix water can be reclaimed through this method, since most of the moisture will
be lost during initial conveyance, evaporation upon placement, and infiltration into
adjacent soil rather than into the collection system. Even 10% may be optimistic unless
the disposal area is first overlaid with impervious material.
Assuming a mix of 80% water to 20% sediment for the slurry, the quantity of water
needed to convey 2.1 million CY would be 8.4 million CY, or approximately 5,200 acrefeet. If 10% of this quantity, about 500 acre-feet, could be recovered, that would reduce
the volume of water required from Lake Casitas from 4,500 acre-feet to 4,000 acre-feet.
30
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
8
PAGE NO: 3 OF 8
The second option would use mix water for conveyance of the slurry from the dam to
the disposal sites, but would then use mechanical methods to extract the water prior to
placement of the slurry material. This would add costs and significant labor to the
disposal process solely for the purpose of extracting water, but might be justifiable
depending on both the financial cost of water from Lake Casitas and the political value
of recycling mix water during drought periods. Dewatering methods include simple
letting the slurry run through a settling tank and recovering water flowing over a weir,
squeezing or centrifugal spinning.
Even if it is assumed that 90% of mix water could be recovered with each use, this
would not totally eliminate the requirement to purchase water from Lake Casitas
altogether. As shown in the table below, after a few iterations without recharge, the
amount of water left for mixing in with the sediment is significantly reduced.
Volume
at start,
acre-feet
500
450
405
365
328
295
266
239
215
194
174
157
141
127
114
103
93
83
75
68
61
55
Number
of uses
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Volume
Recovered
90.00%
90.00%
90.00%
90.00%
90.00%
90.00%
90.00%
90.00%
90.00%
90.00%
90.00%
90.00%
90.00%
90.00%
90.00%
90.00%
90.00%
90.00%
90.00%
90.00%
90.00%
90.00%
31
Volume
returned
450
405
365
328
295
266
239
215
194
174
157
141
127
114
103
93
83
75
68
61
55
49
Total
volume
used
500
950
1355
1720
2048
2343
2609
2848
3063
3257
3431
3588
3729
3856
3971
4073
4166
4250
4325
4392
4453
4508
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
8
PAGE NO: 4 OF 8
ADVANTAGES:
1. Reduces total water consumption
2. Accelerates settling process at slurry disposal areas
3. Reduces costs for buying water from Lake Casitas
DISADVANTAGES:
1. Requires more labor at disposal areas to handle dewatering as well as placement
2. Increases cost at disposal areas for dewatering slurry, collecting drainage and
pumping water back to dam
3. Returning water to reservoir without treatment might reduce water quality of reservoir
JUSTIFICATION:
The only reason to consider this proposal is to reduce water consumption. If there are
drought conditions and increased demand for water from Lake Casitas, there is
obviously a higher priority to consider recycling slurry mix water instead of buying new
makeup water from the lake. If there are enough rain events prior to the sediment
removal project to reduce the financial and human cost of water, there is less advantage
to this proposal.
It should be noted that the cost analysis below does not include labor for added
handling of slurry material for dewatering prior to placement. This is difficult to quantify
compared to the labor already expected for placement of slurry material.
It should also be noted that the estimate on which this study is based was rather dated,
and the costs for features such as water lines were extremely low. The estimate below
updates the water line costs, since that is significant to the analysis but other unit prices
should be verified for programming purposes as design continues.
32
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
8
PAGE NO: 5 OF 8
FIGURE 1: SLURRY LINE ALIGNMENT FROM DAM TO DISPOSAL
33
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
8
PAGE NO: 6 OF 8
FIGURE 2: DOWNSTREAM SLURRY DISPOSAL AREAS
34
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
8
PAGE NO: 7 OF 8
COST ESTIMATE WORKSHEET
PROPOSAL NO. 8: (Spec item # 34 & 36): Recover Water from Slurry Downstream and Pump
It Back Upstream in lieu of Buying Water.
DELETIONS
ITEM
Cost of Water
UNITS
UNIT COST
TOTAL
4,500
$171.00
$0
$769,500
648,000
$1.00
$648,000
1
$125,000.00
$125,000
3,900,000
$0.15
$585,000
LF
42,240
$232.00
$9,799,680
EA
1
$130,000.00
$130,000
EA
3
$112,000.00
$336,000
5,280
13,053,000
$232.00
$0.15
$1,224,960
$1,957,950
2 $3,150,000.00
$6,300,000
$0
ACR-FT
Pipeline Corridor Preparation (24ftx22,000ft) SF
Fresh Water Supply Pumps, 800 HP Each,
Goulds Vertical Turbines, in Parallel
QUANTITY
EA
Power to Pumps from Casitas for 9 Months
Fresh Water Pipeline, 8 Miles Long,
24"x.357" Wall, A53 Cast Iron
Water Storage Tank, 90,000 Gal, 25ftx25ft
Carbon Steel
Makeup Water Pumps, 900 HP Each,
Goulds Centrifugals, in Series
Makeup Waterline, 1 Mile Long, 24"x.357"
Wall, A53 Cast Iron
Power for Makeup System for 9 Months
12" Cutter Head Suction Dredge, 9 Months
Continuous
Slurry System
KW-HRS
Pipeline Corridor Preparation (30ftx41,470ft)
Thickener, 115' Diameter, incl. Flocculant
Package, 40 HP Rake Motor
Slurry Pipeline, 7.85 Miles Long, 20" SRD 11,
HDPE Pipe, 16.146" ID
Slurry Pumps, 1,200 HP Each, Warman
Slurry Pumps in Series
Power for Slurry System for 9 Months
Operation Crew: 4 Operators, 1 Technician,
24hrs x 270 days
Clear disposal area
Construct containment dikes (excavation,
place & compact in disposal area)
Misc. detail at dikes (drainage, grading,
imported stone 4600cy)
Dust Abatement
Site Restoration
Road Repair
SF
LF
KW-HRS
EA
1,244,100
EA
LF
EA
KW-HRS
MAN-HRS
ACR
CY
LS
LS
LS
MILE
$1.00
$1,244,100
1 $1,100,000.00
$1,100,000
41,470
$23.00
$953,810
1
1,934,000
$88,000.00
$0.15
$88,000
$290,100
26,000
97
$54.00
$4,300.00
$1,404,000
$417,100
416,000
$5.00
$2,080,000
1
$671,000.00
1
$135,000.00
1 $1,037,500.00
2
$61,300.00
$671,000
$135,000
$1,037,500
$122,600
$0
$31,419,300
Total Deletions
35
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
8
PAGE NO: 8 OF 8
ADDITIONS
ITEM
Cost of Water
Pipeline Corridor Preparation (24ftx22,000ft)
Fresh Water Supply Pumps, 800 HP Each, Goulds
Vertical Turbines, in Parallel
Power to Pumps from Casitas for 9 Months
Fresh Water Pipeline, 8 Miles Long, 24" HDPE
Water Storage Tank, 90,000 Gal, 25ftx25ft Carbon
Steel
Makeup Water Pumps, 900 HP Each, Goulds
Centrifugals, in Series
Makeup Waterline, 1 Mile Long, 24" HDPE
Power for Makeup System for 9 Months
12" Cutter Head Suction Dredge, 9 Months
Continuous
Slurry System
Pipeline Corridor Preparation (30ftx41,470ft)
Thickener, 115' Diameter, incl. Flocculant Package,
40 HP Rake Motor
Slurry Pipeline, 7.85 Miles Long, 20" SRD 11, HDPE
Pipe, 16.146" ID
Slurry Pumps, 1,200 HP Each, Warman Slurry
Pumps in Series
Power for Slurry System for 9 Months
Operation Crew: 4 Operators, 1 Technician, 24hrs x
270 days
Clear disposal area
Construct containment dikes (excavation, place &
compact in disposal area)
Misc. detail at dikes (drainage, grading, imported
stone 4600cy)
Dust Abatement
Site Restoration
Road Repair
Water Pipeline from Disposal Area back to Matilija,
7.85 Miles Long, 8" HDPE
Power to Pumps from Disposal Area for 9 Months
Water Supply Pump from Disposal Area to Matilija,
only used at one site at a time
Spillway collection system
UNITS
QUANTITY
UNIT COST
TOTAL
2,500
648,000
$171.00
$1.00
$0
$427,500
$648,000
1
2,000,000
42,240
$125,000.00
$0.15
$232.00
$125,000
$300,000
$9,799,680
1
$130,000.00
$130,000
3
5,280
6,526,500
$112,000.00
$232.00
$0.15
$336,000
$1,224,960
$978,975
EA
2
$3,150,000.00
SF
1,244,100
$1.00
$6,300,000
$0
$1,244,100
EA
1
$1,100,000.00
$1,100,000
LF
41,470
$23.00
$953,810
1
1,934,000
$88,000.00
$0.15
$88,000
$290,100
26,000
97
$54.00
$4,300.00
$1,404,000
$417,100
416,000
$5.00
$2,080,000
1
1
1
2
$671,000.00
$135,000.00
$1,037,500.00
$61,300.00
$671,000
$135,000
$1,037,500
$122,600
$0
41,448
1,300,000
$22.00
$0.15
$911,856
$195,000
1
1
$125,000.00
$30,000.00
$125,000
$30,000
$0
$31,075,181
ACR-FT
SF
EA
KW-HRS
LF
EA
EA
LF
KW-HRS
EA
KW-HRS
MAN-HRS
ACR
CY
LS
LS
LS
MILE
LF
KW-HRS
EA
LS
Total Additions
Net Savings
Markups
Total Savings
36
42.50%
$344,119
$146,251
$490,370
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
DESCRIPTION:
9
PAGE NO: 1 OF 4
Overexcavate slurry disposal site and mix silt with reserved
in-situ material to facilitate revegetation and post project uses
ORIGINAL DESIGN:
Current design indicates eight slurry disposal sites downstream, as shown below on
Figure 4-2 from the Recommended Plan. The eight sites have a combined capacity for
2,783,000 cubic yards, which allows for some swell of the 2.1 million cubic yards of
sediment while being placed.
Prior to placement, the area will be cleared of vegetation to enhance percolation. The
thickness of the required placement will vary by area and range between 10 and 25
feet. Earthen containment dikes will be constructed to contain the slurried materials.
The dikes will be constructed of sands and gravels obtained from required on-site
excavation and grading. Slopes on the basin side will be 2H: 1V; slopes on the outside
of the basin are assumed to be 3H: 1V.
For the upstream-most slurry disposal site located just north of the Highway 150 Bridge,
slope protection will be required and will consist of riprap stone of approximately 2-foot
diameter. The other disposal areas are located mostly on low floodplain terraces and
would be subjected to less frequent flows. Stone protection for these areas to a limited
height may consist of boulders obtained from excavation activities for the construction of
the dikes. Willows may also be planted on the side slopes to provide soil stabilization
during larger storm events. Once the slurried materials are sufficiently dewatered, the
disposal areas can be revegetated using native plants.
PROPOSED DESIGN:
Following clearing, stockpile the top three feet of surface soils. Once the disposal area
in use is close to final placement grade, mix this material in with the top layer of slurry
material.
ADVANTAGES:
1. The dryer and sandier material from the disposal area would allow easier movement
of grading equipment
2. The stockpiled material would probably already contain native vegetation, so less
planting would be required
3. The mix of soils should allow quicker germination and growing of new vegetation
37
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
9
PAGE NO: 2 OF 4
DISADVANTAGES:
1. Added costs for excavation and stockpiling
2. Soil to be stockpiled would have to be examined first to ensure it did not contain
invasive species
3. There might be added costs if revegetation occurs in the stockpile itself
JUSTIFICATION:
This is an added cost, but might make final grading and revegetation easier for
contractor to the extent that operations are quicker and more efficient. It is suggested
that this be allowed at the contractor’s discretion, but not included in the quantities for
which the contractor is paid. Payment would be based on sediment placed, exclusive of
the stockpiled topsoil.
38
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
9
PAGE NO: 3 OF 4
39
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
9
PAGE NO: 4 OF 4
COST ESTIMATE WORKSHEET
Proposal 9
DELETIONS
ITEM
Clearing and Grubbing
Hydroseeding with mulch and fertilizer
UNITS
Acres
MSF
QUANTITY
UNIT COST
118
5140
$3,550.00
$42.00
Total Deletions
TOTAL
$0
$418,900
$215,883
$0
$0
$0
$0
$0
$0
$634,783
ADDITIONS
ITEM
Clearing and Grubbing
Topsoil stripping and stockpiling, 6" deep
Excavation to 3 feet deep, haul 1500'
Backfilling
Compaction in 6" lift
Hydroseeding with mulch and fertilizer
UNITS
Acres
SY
CY
CY
CY
MSF
40
QUANTITY
UNIT COST
TOTAL
Total Additions
$0
$418,900
$748,167
$1,724,782
$828,124
$1,644,826
$215,883
$0
$5,580,683
Net Savings
Markups
Total Savings
-$4,945,899
-$2,102,007
-$7,047,906
118
571120
571120
571120
571120
5140
$3,550.00
$1.31
$3.02
$1.45
$2.88
$42.00
42.50%
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
DESCRIPTION:
10
PAGE NO: 1 OF 2
Mix in silts with sands for disposal upstream to
facilitate revegetation of upstream disposal sites
ORIGINAL DESIGN:
The current plan proposes to slurry all silt materials from the reservoir area and place
them downstream below the Robles Diversion Dam into confined disposal areas.
PROPOSED DESIGN:
The proposed plan is to utilize some of these slurry materials and incorporate them into
the top layer of upstream disposal materials to create an enhanced soil mixture which
will facilitate the regeneration of vegetative growth.
ADVANTAGES:
1.
2.
3.
4.
Enhances the environmental aspects of the disposal sites.
Reduces the size of the downstream disposal area requirements.
Eliminates some of the water needed to transport the slurry downstream.
Provides for higher capacity of water storage for future slurry transport.
DISADVANTAGES:
1. Will require the use of additional construction equipment to handle and perform the
mixing process for these materials.
JUSTIFICATION:
There is potential for significant savings of first cost and construction duration with no
significant risk increase. Also provides benefits which enhance the environment.
41
VALUE ENGINEERING PROPOSAL
PROPOSAL NO:
10
PAGE NO: 2 OF 2
COST ESTIMATE WORKSHEET
PROPOSAL NO.: Matilija # 10 - Mix in Silts with Sands to Enhance Vegetation Growth
DELETIONS
UNITS
cy
ITEM
Slurry Material
(assumed 6" of fill over 134.6 acres)
QUANTITY
110,000
UNIT COST
$10.08
TOTAL
$1,108,800
$1,108,800
Total Deletions
ADDITIONS
ITEM
Silt Placement (hydraulic equipment)
UNITS
cy
QUANTITY
110,000
Mixing Materials by Discing (assume top 18")
acres
134.6
UNIT COST
$1.25
TOTAL
$137,500
$850.00
$114,410
$251,910
Total Additions
Net Savings
Markups
Total Savings
42
42.50%
$856,890
$364,178
$1,221,068
VALUE ENGINEERING COMMENTS
1. Make silt available for commercial use. Approximately 6 Million Cubic Yards
(MCY) of sediment has deposited behind the reservoir. The Recommended Plan
includes full dam removal, short-term storage of 4 million cubic yards (MCY) of coarse
material, slurry of 2.1 MCY of fine sediments, modification of Robles Diversion Dam
approximately 2 miles downstream, and downstream bridge modifications, levees and
addition of a recreation trail. The fine sediment deposited in the “Reservoir”
(immediately upstream of the dam) is to be slurred downstream to disposal site prior to,
or concurrent with, removal of the dam. Based on geotechnical investigations, there are
approximately 2.1 MCY of fines, about 85 % passing the number .200 sieve, stored in
this area. This proposal is to make a deposal site upstream of the dam with the fine
sediment and make it available for commercial use.
2. Use sectional barge dredge. When the Matilija Dam was built in 1947 , it had
initial reservoir capacity of 7,018 ac-ft and it impounds Matilija Creek. Matilija Reservoir
currently has less than 500 ac-ft of capacity remaining and its ability to trap sediment
and attenuate floods has been significantly decreased. The upstream end of the Majilija
Reservoir Delta is at River Mile (RM) 17.64; the upstream end of the Majilija Reservoir
is at River Mile (RM) 16.58 and the Mitilija Dam is at River Mile (RM) 16.31. The
reservoir is only about one quarter mile long. The access road to the dam reservoir is
very narrow, steep and winding. In addition, the reservoir is surrounded with highdensity vegetation and steep banks. With flood damage reduction and ecosystem
restoration as major goals, this makes the use of sectional barge dredge very desirable.
43
VALUE ENGINEERING COMMENTS
Figure1. Picture of the front of the dam and reservoir
(Aerial View of Matilija Dam taken April 2004)
Figure 2. Picture of the back of the dam and reservoir
44
VALUE ENGINEERING COMMENTS
3. Relocate sediment storage sites to avoid blocking tributaries in reservoir area.
As shown in the Recommended Plan figure below, there are a few areas above Matilija
Dam where sediment will be temporarily stored following dam removal. The intent is to
maintain a lower flow channel for the Ventura River, but allow future erosion and
sediment transport by high flow events, with the goal of eventually restoring the entire
reservoir area to pre-Matilija contours. It is uncertain, however, how these high-flow
events can be prevented from transporting a large slug of sediment and then dropping it
at a lower energy point, i.e., wider channel section, as a future obstruction to flow,
increasing risks of flood damages. While the layout appears to accommodate some of
the major inflows, future design should take this into greater account.
4. Use tributaries to help erode slurry disposal sites. While this may appear to be a
reverse of the previous comment, it is suggested that each of these temporary disposal
sites include a pre-planned failure feature which can be removed at designated times to
allow that particular site and only that site to be transported downstream by high-flow
events. An example could be a dike with a specific weak point to be removed when the
stakeholders agree it is time for more sediment to be sent downstream.
45
VALUE ENGINEERING COMMENTS
5. Push a specific volume of stored slurry material into the channel at the Hwy
150 bridge to be transported by the next storm event. One of the objectives of the
Matilija Dam Removal Project is to allow coarser soil and rock materials that have filled
the reservoir to pass downstream in controlled releases by natural processes. The
current plan is to pump silts and fine materials downstream of the Robles Diversion in
order to protect the and place that material in disposal areas. Consideration should be
given to preplacing a specific volume of stored slurry material into the channel
downstream of Lake Casitas. This would reduce the distance to transport the material
and would accelerate the delivery of sediment downstream.
6. Optimize size and location of delta area storage sites to minimize use of soil
cement. The feasibility report shows the preliminary design for the shape and location
of channel mimicking the original (pre-project) alignment of the channel. This may or
may not be the best alignment for the channel and may not result in an optimal amount
of soil cement being used. It appears that considerable thought and effort have already
gone into the design and placement of this material, “selective segments of the
channel”. Removal of the material is already designated to “occur in stages , and will be
dependent on criteria established in the monitoring and adaptive management plan”.
During detailed design the alignment should continue to consider the costs and other
factors relating to alignment to result in the most efficient use of resources to achieve
project goals.
46
VALUE ENGINEERING COMMENTS
7. Do not constrain both sides of channel in reservoir; only use soil-cement on
one side. The sediment excavated from the “Delta Area” will be placed in storage sites
within the lower half of the reservoir basin. These materials contain the majority of the
residual portions of the finer sediment trapped in the basin. The purpose of the soil
cement is to meter the erosion of the delta area sediment whenever the revetment is
overtopped by larger flows. The design intent of using the soil-cement is to temporarily
reduce the quantity of heavy silt that would re-enter the Matilija river during periods of
high runoff. The soil cement revetment would be removed from the site following
sufficient evacuation of stored sediment from within the original reservoir limits. The
removal will occur in stages, and will be dependent on criteria established in the
monitoring and adaptive management plan taking into account levels of sediment
evacuation and limiting adverse effects downstream. Soil cement on one side only
would lead to a substantial loss of control of the “metering” of material and a resultant
loss of control of the impacts downstream. In particular, this would result in higher
turbidity and silty deposition downstream and have an impact on the water quality of
water in the Casitas diversion. The savings would be approximately $680,000 of direct
construction cost for approximately ½ the amount of soil cement. Costs would be much
more difficult to quantify for mitigation. For further consideration of this alternative
analysis would have to be performed of the potential outcomes and associated
mitigation costs.
8. Allow use of large boulders in some areas in lieu of soil-cement. The current
design includes soil-cement being used for bank protection on the first five feet vertically
for temporary sediment storage areas in the reservoir area above Matilija Dam, as
shown in the plan (Fig. 1) and cross-section (Fig. 2) below. It was suggested to use
stone protection in lieu of soil-cement, since that would protect the slope and provide a
more natural appearance. It was noted in Figure 3 below, however, that there are
occasions when the peak flow through this narrow channel could reach as high as
20,000 cfs. A flow as high as this could move some pretty huge boulders down the
channel. This is why the design used soil-cement to keep the huge flows from
undercutting the slope for the temporary sediment storage areas. On the other hand,
the intent of the temporary storage is to allow eventual movement of the sediment
downstream. Therefore, it is suggested to accept the risk of some boulder movement
by extreme flows, and use the more naturally appearing slope armoring method. Piping
of some fines through the rock would also be in tune with the eventual goal.
47
VALUE ENGINEERING COMMENTS
Comment 8, Figure 1
Comment 8, Figure 2
48
VALUE ENGINEERING COMMENTS
Comment 8, Figure 3
9. Refine design of channel substrate, slope, velocity for habitat function.
Recommendation correctly suggests that riparian habitat functions can be enhanced
with appropriate consideration of design parameters. All three factors, and others,
intertwine to create conditions that allow for establishment of and use by riparian
species. Because the system is capable of moving sediment of considerable size and
quantity, design should consider the contribution of large sediment as a permanent
feature as well as dissipation of energy within the stream corridor, such as
determination of natural sinuosity and perhaps use of grade control features such as
chevroned rock groins to create low step pools, cobble fields on mild gradients to
provide a riffle between pool areas, within-channel boulder clusters to provide shelter,
etc. All of these considerations would likely be heavily modified by natural processes in
a relatively short term.
49
VALUE ENGINEERING COMMENTS
10. Stockpile concrete rubble onsite and offer / sell it to the public in lieu of
paying to haul it to a recycling site. The cost estimate for the project identifies
72,285 CY of concrete rubble to be hauled to a recycling plant. This large quantity of
concrete material may be attractive to a private company as a source of revetment
material or other use without processing. Consideration should be given to offering or
selling the concrete rubble for pick up at the site, which would reduce or eliminate the
cost of hauling.
11. Partially remove dam to existing dam crest before main construction project.
This proposal is to do a partial dam removal to the existing dam crest before the main
construction project starts. This would mean that there would be two contracts. The first
Contract would be a partial removal of the dam to the existing dam crest. The dam
concrete would be taken down to the existing notched level (1097.6 EL) of the exiting
dam (1127.6 EL). The second Contract would be a complete removal of the remainder
of the dam down to the stream bedrock prior to, or concurrent with, removal of the
sediment deposited behind the dam.
12. Allow contractor to select method of excavation. Rather than specifying a
particular type of dredging equipment for sediment removal, this portion of the project
should be contracted as a request for proposals, allowing the contractor the option of
using alternatives, such as dragline, or amphibious dredge. Environmental or public
safety restrictions, such as turbidity limits, silt curtains or screens to protect waterlife
from the cutterheads, operational windows, etc, will still need to be identified in the RFP,
and a method of weighting selection criteria would have to be determined based on
stakeholder consensus.
50
VALUE ENGINEERING COMMENTS
13.
Utilize large logs for revetment and/or stream restoration.
This
recommendation comprises two concepts: use of large trees for bank protection and
use of large logs for (partial) stream restoration. For either use, the logs utilized should
be harvested from the creek within the work areas. For bank protection, the available
trees may be of limited value unless a sufficient quantity of suitable trees was on hand.
If not, bank protection using large logs would be limited to relatively small areas, and
likely in areas protected from high stress. For stream restoration, woody debris
contributes to dissipation of energy and local hydraulic variability associated with
obstruction, storage of sediment, and provision of habitat. Available biomass, of which
large woody debris is one example, is a fundamental component of nutrient turnover
within the riparian ecosystem. Other components include smaller woody debris, leaf
litter, root biomass, herbaceous vegetation, and faunal components. Because the
project entails complete removal of accumulated sediments upstream of the dam,
including the well-established riparian habitat, the resulting substrate would be devoid of
most biomass in the short term. Consequently, use of large logs would constitute a
relatively minor contribution to restoration of riparian biomass, but could contribute a
structural component to stream morphology in the form of anchored rootwads (clustered
unless of sufficient size) or other means of bank protection.
14. Revisit Bridge Replacement Costs. The cost estimate includes costs for
removing and replacing the Camino Cielo Bridge with a 150’ long bridge and modifying
the Santa Ana Bridge with a 75’ extension. The costs are $5.1 and $2.8 million
respectively. These costs seem very excessive considering the duration of any event
that they pass. Consider reevaluation to insure that life cycle costs were considered as
well as demand need impacts. The cost to replace the Camino Cielo Bridge in-kind
would probably be on the order of $100,000 or less.
51
VALUE ENGINEERING TEAM STUDY
APPENDICES
SUPPORTING DOCUMENTS
52
VALUE ENGINEERING TEAM STUDY
APPENDIX A:
CONTACT DIRECTORY
53
VALUE ENGINEERING TEAM STUDY
APPENDIX A: CONTACT DIRECTORY & VE STUDY TEAM MEMBERS
NAME
ORGANIZATION
TELEPHONE
Rick Lambert
OVEST (civil / structural engr)
richard.d.lambert@usace.army.mil
843-329-8063
Bill Easley
OVEST (interdisciplinary / civil engr)
william.s.easley@usace.army.mil
843-329-8152
John Mathis
OVEST (interdisciplinary / mech engr)
john.w.mathis@usace.army.mil
843-329-8041
Jim Henderson
CESAW (regional cost engr)
843-329-8141
james.e.henderson.jr@usace.army.mil
Brad Bird
CENWP (hydraulic engineer)
brad.a.bird@usace.army.mil
503-808-4878
Bruce Henderson
CESPL (biologist)
bruce.a.henderson@usace.army.mil
805-585-2145
Doug Chitwood
CESPL (project lead)
douglas.e.chitwood@usace.army.mil
213-452-3587
Darrell Buxton
CESPL (project manager)
darrell.w.buxton@usace.army.mil
213-452-4007
Jim Hutchison
CESPL (ch, watershed studies group)
james.d.hutchison@usace.army.mil
213-452-3826
Blair Greimann
US Bureau of Reclamation (hydraulic)
bgreimann@do.usbr.gov
303-445-2563
Steve Thomas
NOAA Fisheries
steve.thomas@noaa.gov
707-575-6079
Mark Capelli
NOAA (recovery coordinator)
Mark.capelli@noaa.gov
805-963-6478
Marcin Whitman
California Fish & Game (engineer)
mwhitman@dfg.ca.gov
916-445-3832
54
NAME
ORGANIZATION
TELEPHONE
Peter Sheydayi
Watershed Protection District
peter.sheydayi@ventura.org
805-654-2016
Karen Waln
City of Ventura (management analyst)
kwaln@ce.ventura.ca.us
805-677-4128
Paul Jenkin
Matilija coalition / surfrider fdn
pjenkin@sbcglobal.net
805-648-4005
Pam Lindsey
Ventura Co Watershed Protection Dist
pam.lindsey@ventura.org
805-654-2036
55
VALUE ENGINEERING TEAM STUDY
APPENDIX B:
FUNCTION ANALYSIS
SYSTEM TECHNIQUE
(FAST) DIAGRAM
56
57
VALUE ENGINEERING TEAM STUDY
APPENDIX C:
COST MODEL
58
COST MODEL:
Matilija Dam Removal
Dam removal
$14,876,500
Bridge replacements
$11,259,080
Land, easements, right-of-way
$10,365,693
12" cutter head suction dredge
$8,978,760
Import water from Casitas
$7,571,275
Arundo control
$7,172,319
Mob / Demob
$7,126,000
High flow sediment bypass at Robles
$6,627,180
Relocations
$6,513,164
Slurry system
$5,239,049
Channel excavation
$4,758,743
Levees / Floodwalls
$4,009,088
Construct containment dikes
$2,964,416
Misc dike grading, dust, restoration, road work
$2,802,086
Soil cement wall
$2,689,352
Operation crew
$2,000,981
Arundo eradication
$1,697,698
Wells
$1,140,160
Real estate admin
$762,482
Clear & Grub
$728,961
Clear disposal area
$594,451
Disposal site closure
$285,040
Fish rescue & relocation
$142,520
Diversion and control of water
$142,520
$0
$5,000,000
59
$10,000,000
$15,000,000
$20,000,000
VALUE ENGINEERING TEAM STUDY
APPENDIX D:
SPECULATION LIST
60
VALUE ENGINEERING TEAM STUDY
APPENDIX D: SPECULATION LIST
Spec
Item Description
P
1
Use geotubes in lieu of soil-cement
P
2
Use conveyor to transport sediment in lieu of slurry
X
3
Pay for lost diversion opportunity in lieu of buying water for slurry
X
4
Flood-proof flood-prone structures vs. building levees
P
5
Optimize dredging placement of all materials; remove delta first, place
more material upstream and recreate lake to collect more water for
slurrying in lieu of buying water; pump slurry downstream eventually
BD
6
Use controlled blasting to remove dam
BD
7
Use controlled blasting in coordination with dredging
P
8
Recycle concrete onsite (minus rebar)
P
9
X
10
BD
11
P
12
Use temporary reservoirs to increase water supply for single season
for slurry
Partially remove dam for dewatering; use conventional excavation for
removal of sediment
Remove left side of dam (looking downstream) for better access to
delta area
Do not remove entire dam; leave part of the abutments
X
13
Build up slope to intersect with partially removed dam
X
14
Revise mix of slurry to make it acceptable for downstream uses
C
15
Make silt available for commercial use
X
16
X
17
Use concrete rubble (minus rebar) from dam removal in lieu of soil
cement
Wire-cut concrete and use concrete blocks for retaining structure in
lieu of soil cement
Bury vegetation in sediment storage sites in lieu of removal
P
18
BD
19
X
20
Research most cost-effective method for removing arundo (giant
reed)
Import goats which eat arundo
C
21
Use pontoon-mounted sectional dredge
C
22
C
23
Relocate sediment storage sites to avoid blocking tributaries in
reservoir area
Use tributaries to help erode slurry disposal sites
X
24
X
25
Extend slurry line all the way to ocean to enable beach renourishment
and/or deepwater disposal
Use enclosed wind turbines for pumping energy
X
26
Use solar panels to power pumps
X
27
C
28
BD
29
Do a partial dam removal and create a diversion tunnel on left side of
dam for sediment passage and fish passage
Push a specific volume of stored slurry material into the channel at
the 150 bridge to be transported by next storm event
Identify in the contract a specific period for dredging to be done
61
C
30
Optimize size and location of delta area storage sites to minimize use
of soil cement
Do not constrain both sides of channel in reservoir; only use soilcement on one side
Allow use of large boulders in some areas in lieu of soil-cement
C
31
C
32
C
33
P
34
X
35
P
36
X
37
BD
38
X
39
C
40
BD
41
C
42
X
43
Sort reservoir delta area material to remove fines to eliminate
requirement for soil-cement
Stockpile concrete rubble onsite and offer/sell it to public in lieu of
paying to haul it to recycling site
Remove above grade structures prior to main construction project to
enable easier access
Partially remove dam to existing dam crest before main construction
project
Space out construction sequencing to keep pace with turbidity limits
C
44
Allow contractor to select method of excavation
P
45
P
46
C
47
Overexcavate slurry disposal site and mix silt with reserved in-situ
material to facilitate reveg and post project uses
Mix in silts with sands for disposal upstream to facilitate reveg at
upstream disposal sites
Utilize large logs for revetment and / or stream restoration
C
48
Revisit bridge replacement costs
Refine design of channel substrate, slope, velocity for habitat
function
Recover water from slurry downstream and pump it back upstream in
lieu of buying water
Capture energy from slurry going downstream and use it to pump
water upstream
Modify storage basins to recover more slurry water for reuse w/34
Explore advantages of segregating soil types from slurry for
beneficial use
Recycle concrete from dam
P = Proposal
C = Comment
BD = Being done
X = Rejected
62