Chehalis Basin Strategy: Reducing Flood Damage and Enhancing Aquatic - - PowerPoint PPT Presentation

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Chehalis Basin Strategy: Reducing Flood Damage and Enhancing Aquatic - - PowerPoint PPT Presentation

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Chehalis Basin Strategy: Reducing Flood Damage and Enhancing Aquatic Species November 13, 2013 Policy Workshop Tasks 1.1.1 Dam Design and 1.1.2 Fish Passage Research Findings Presenters: Keith Ferguson, P.E. Mike Garello. P.E. 11/11/2013

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Chehalis Basin Strategy: Reducing Flood Damage and Enhancing Aquatic Species

November 13, 2013 Policy Workshop Tasks 1.1.1 Dam Design and 1.1.2 Fish Passage Research Findings Presenters: Keith Ferguson, P.E. Mike Garello. P.E.

11/11/2013

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Introduction

  • Objectives
  • Present preliminary dam and fish passage research findings
  • Identify any additional research needs with regard to dam

alternatives and fish passage

  • Presentation
  • Task 1.1.1 Dam Design Study
  • Task 1.1.2 Fish Passage Design
  • Q&A/Discussion

11/11/2013

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Outline

  • Background Information
  • Dam Examples – learning from the past
  • Site Visit Findings
  • Dam Types
  • Hydraulic Structures
  • Slots and Tunnels for Fish Passage
  • Flood Control and Operation Outlets
  • Auxiliary Spillways
  • Fish Passage
  • Debris Management
  • Research Findings and Next Steps

11/11/2013

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Chehalis Dam Alternatives

Multipurpose

Flood Control Water Storage Fisheries Hydropower Recreation

Flood Control Only

Flood Control Fish Passage

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Ranking and Similar Projects

  • Dam Height (from previous evaluations)
  • Flood Control Only = 238 feet
  • Multipurpose = 288 feet
  • Research; leveraging roles and relationships with USSD and ICOLD
  • Internationally
  • Rockfill and Concrete (RCC) up to 1,000 feet high being constructed
  • Nationally
  • A Dam over 290 feet would be in the top 100 dams (out of about 80,000) in

the United States with regards to height (the top 0.1%).

  • Leading the way on multi‐purpose, sustainability, and environmentally

enhanced dams

11/11/2013

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Dams in the US

  • Last 25 years
  • More than 8,900 NID

new dams built

  • More than 1,500 NID

dams modified

11/11/2013

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Dams in the US

  • For new dams:
  • 10% greater than 50’ high
  • 15% high hazard potential (HHP)
  • HHP dams under

construction in 2012:

  • 33 less than 50’
  • 16 between 50’ and 100’
  • 7 over 100‘

11/11/2013

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Dam Types

11/11/2013

Concrete Arch Gravity Concrete Gravity RCC

Embankment Rockfill Earth Fill Composite and Other

Gravity RCC with Embankment Wing

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Design Criteria

11/11/2013

  • Flood Control Only
  • High Hazard Potential
  • Dam Safety Flood – PMP
  • Watershed debris

management, screening and handling

  • Seismic Loading ‐ < MCE
  • Some cracking allowed

for concrete dams

  • Multi‐purpose
  • High Hazard Potential
  • Dam Safety Flood – PMP
  • Debris screening and

handling

  • Seismic Loading – MCE

with partial pool

  • Cracking may not be

allowed for concrete dam alternatives

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Key Site Considerations

Seismic Hazards

  • 1/2,500 year ‐ 0.56g pga
  • 1/5,000 year ‐ 0.72g pga

Landslide Hazards

  • Landslide debris at the dam site on both banks of the

Chehalis River and in the reservoir

  • Construction and long‐term risks

Foundation Conditions

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Existing Dam Examples

11/11/2013

Learning from the Past

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Flood Control Only Mud Mountain Dam, WA

11/11/2013

Location: Enumclaw, Washington Operator: Seattle District, Corps of Engineers Dam Type: Earth/rockfill Embankment (1948) Length: 315 feet Height: 380 feet Low level flood control conduits and auxiliary spillway

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Flood Control Only – Morris Dam, NY

11/11/2013

Location: Leicester, NY Operator: USACE – Buffalo District Dam Type: Concrete Gravity Length: 1,028 feet Height: 230 feet Low level conduits and Overflow Spillway

Downstream Upstream

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Flood Control Only Miami Conservancy District – 5 Dams, OH

11/11/2013

Location: Southwest, OH Operator: Miami Conservancy District Dam Type: Earth Embankment Length: 1,210 – 6,400 feet Height: 65‐110 feet Low level conduits and Overflow Spillways

Englewood Germantown Lockington Huffman Taylorsville

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Multipurpose Detroit Dam, OR

11/11/2013

Location: Salem, OR Operator: USACE – Portland District Dam Type: Concrete Gravity Length: 1,523 feet Height: 463 feet Low level conduits and Overflow Spillway

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Flood Control Only Miami Conservancy District – 5 Dams, OH

11/11/2013

Location: Southwest, OH Operator: Miami Conservancy District Dam Type: Earth Embankment Length: 1,210 – 6,400 feet Height: 65‐110 feet Low level conduits and Overflow Spillways

Englewood Germantown Lockington Huffman Taylorsville

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Site Visit

11/11/2013

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Dam Site Aerial Views

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Site Visit

October 1, 2013

AERIAL KEY

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Site Visit

October 1, 2013

AERIAL KEY

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Site Visit

October 1, 2013

AERIAL KEY

  • Approx. Dam Crest
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Dam Types

11/11/2013

Concrete Arch Gravity Concrete Gravity RCC

Embankment Rockfill Earth Fill Composite and Other

Gravity RCC with Embankment Wing

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Roller Compacted Concrete Dams

  • Speed of

construction

  • Cost
  • Integrated

structural elements

  • Effective seepage

barriers

  • Crack control

strategies

Olivenhain Dam, CA 2004 New Big Cherry Dam, VA 2006

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Concrete Dam

  • Advantages
  • Most flexible range of flood
  • perations
  • Most flexible range of fish

passage options

  • Lowest cost outlet works with

maximum water quality

  • perations and effectiveness
  • Fastest construction schedule
  • Challenges
  • Requires “rock” foundation at

reasonable depth

  • Construction materials
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Central Clay Core Rockfill Dam

11/11/2013

Creekside Greywater Reservoir, OR, 2007

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Rockfill Dams

  • Advantages
  • Good seismic response
  • Very cost effective for dams
  • ver 150‐feet‐high
  • Good dam for “rock” sites

with clay source

  • Challenges
  • Flexible flood operations
  • Limited fish passage options
  • Intermediate construction

duration

  • Construction materials
  • Core
  • Filters/drains
  • Rockfill

Diamond Valley Reservoir, CA 2000

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RCC/Embankment Composite Dam

11/11/2013

Location: Folsom, CA Operator: USACE/USBR Joint Federal Project Dam Type: Concrete and Earthen Length: Main 1,400 feet Height: 340 feet Gated Concrete Spillway

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Earthfill dam

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Dam Type Findings

11/11/2013

Concrete Arch Gravity Concrete Gravity RCC

Embankment Rockfill Earth Fill Composite and Other

Gravity RCC with Embankment Wing

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Rockfill/Embankment Dam CL Axis Concrete Dam with Embankment Wingdike Axis

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Hydraulic Structures

11/11/2013

Gates Stoplogs Valves

Approach Canals and Channels

Auxiliary Spillway Fish Passage Flood Control Outlet Slots in Dams

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Findings – Slots in Dams

  • Open Slot – limited to very low head applications
  • Modified Slots – limited to 80 to 100 feet
  • Gated Slots not designed for flood overtopping

11/11/2013

Open Slot Gated Slot Baffled Slot

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Outlet Tunnels – Base of Concrete Dam

11/11/2013

VERTICAL SLIDE GATE SLOTS

Moose Creek Dam, USACE, Alaska

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Outlet Tunnel ‐ Abutments

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Intake Towers – Upstream Face of Dam

11/11/2013

Project: New Big Cherry Dam Location: Big Stone Gap, VA Operator: Town of Big Stone Gap Dam Type: Roller Compacted Concrete

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Findings – Flood Control Outlets

  • Many configurations possible
  • Seismic loads will be challenge for free‐standing

tower and large gates

  • Both controlled and uncontrolled operations
  • Debris management a significant consideration

11/11/2013

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Overflow Spillway

  • Over Center of Dam (Concrete Alternatives)
  • Abutment (Rockfill Alternatives)

11/11/2013

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Findings – Auxiliary Spillway

  • Will be a dam safety requirement
  • Sized based on Inflow Design Flood (IDF) routing
  • Controlled or uncontrolled configurations
  • Seismic loads will be significant challenge
  • Debris control will be significant consideration

11/11/2013

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Fish Passage

11/11/2013

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Fish Passage Research

Several potential fish passage technologies were evaluated from around the world and the Pacific Northwest.

11/11/2013

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Summary of Fish Passage Technologies

  • Upstream
  • Fishways (Nature‐Like and Conventional)
  • Lifts, locks, and elevators
  • CHTR – Collect, Handle, Transfer, and Release “Trap and Haul”
  • Bypass Facilities
  • Downstream
  • Surface Spill
  • Forebay Collector
  • CHTR
  • Turbine Passage
  • Bypass Facilities

11/11/2013

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Fish Passage Background

  • The Fish Ladder
  • Example ‐ Ice

Harbor Style Fishway Ice Harbor Dam, WA

11/11/2013

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7 20 5

5 10 15 20 25 30 35 40

Number of Upstream Passage Facilities 34 11

5 10 15 20 25 30 35 40

Number of Upstream Passage Facilities

50 to 150 feet 150+ feet

32 Projects Included in Survey 45 Projects Included in Survey

Fish Passage at High Dams – Western US (WA, OR, CA, ID)

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Fish Passage Trends for High Dams

  • Most projects at high head dams in Pacific

Northwest use CHTR for upstream passage

  • Forebay collectors are the most recent

downstream passage technological advancement

  • Mitigation hatcheries often used in tandem with

passage

11/11/2013

Fish Ladders and Lifts Built During Dam Construction Fish Ladders and Lifts Modified and

  • r Abandoned

New CHTR and Forebay Collectors Constructed

1920s to 1930s 1950s to 1970s 1990s to Current

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Potential Fish Passage Structures

11/11/2013

Multi‐Purpose Dam

  • CHTR
  • Forebay Collector
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Potential Fish Passage Structures

11/11/2013

Flood Control Only Dam

  • Bypass Tunnel
  • CHTR
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Anticipated Fish Species

SPECIES UPSTREAM DOWNSTREAM Chinook salmon (spring and fall run) Adult/Juvenile Juvenile Coho salmon Adult/Juvenile Juvenile Steelhead Adult/Juvenile Adult/Juvenile Pacific Lamprey Adult Ammocoetes / Macropthalmia Western Brook Lamprey Adult Ammocoetes / Macropthalmia Bull Trout Adult/Juvenile Adult/Juvenile Coastal Cutthroat Adult/Juvenile Adult/Juvenile

11/11/2013

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Fish Passage Findings

  • CHTR and Forebay Collector type facilities are

more frequently used for high dam passage

  • Integration of a bypass tunnel through a flood

control only dam would be an innovative approach to providing fish passage for all species

11/11/2013

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Debris and Sediment Management

11/11/2013

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Typical Debris Accumulation during Large Flood Event at Howard Hansen Dam, Washington

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Debris Guard Gates at Moose Creek Dam, USACE, Alaska

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Moose Creek Dam, USACE, Alaska

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Moose Creek Dam, USACE, Alaska

Alternative Debris Management Strategies:

  • Routine reservoir inundation and debris

removal

  • Routine clearing/grubbing
  • Debris removal following flood events
  • Alternative debris management and

removal provisions in design elements

  • Reservoir Operations to manage

Sediment accumulation

  • Sediment flushing systems
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Summary of Research Findings

  • New dams over 100’ in height are being constructed in

the US

  • Design criteria would be more stringent for a multi‐

purpose dam than for flood control only

  • The site appears to be best suited for either a RCC,

rockfill, or RCC/embankment composite dam

  • A slotted dam would not be suitable for this high dam

application

11/11/2013

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Summary of Research Findings (cont)

  • Several alternative configurations could be suitable

hydraulic outlet, spillway, and bypass structures

  • CHTR and forebay collection fish passage would be

most suitable for high dam fish passage

  • A flow through channel or tunnel would provide

innovative fish passage for a flood‐control only dam

  • Debris and sediment management will be an

important part of the dam/passage design

11/11/2013

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Next Steps

  • Finalize configuration design criteria
  • Fish Passage Workshop this week
  • Dam configuration Workshop in early December
  • Draft alternative dam and fish passage configurations

for flood control only and multi‐purpose dams

  • Integrate operations criteria to refine recommended

dam and passage systems

  • Draft Dam Design TM – February 28, 2014

11/11/2013