POWER POINT PRESENTATION FROM BRETT TOWLER, US FISH AND WILDLIFE SERVICE

Fishways: An Overview

Brett Towler, Regional Fish Passage Engineer, USFWS

IFC-USAID Fish Passage Workshop - 2016, Nepal

Fishway, fish passageway, fish pass • Synonymous terms though fishway is most common • Applies to upstream, downstream, volitional and nonvolitional devices and structures

Technical fishway • Made from concrete, steel or wood often comprised of uniform pools, prismatic channels and moving parts; upstream and downstream are often separate fishways

Nature-like fishway • High-gradient, engineered channels that mimic natural in-stream structures to provide a diversity of hydraulic conditions; combined upstream and downstream IFC-USAID Fish Passage Workshop - 2016, Nepal

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Volitional • Fish ascend (or move through) fishway willingly • ladders, not lifts • Functionality based on rheotaxis • Less moving parts; lower O&M • Higher energetic cost for fish

Non-Volitional • • • •

Fish are carried or moved mechanically Lifts, locks, and trap & transport Many moving parts; higher O&M Low energetic cost for fish, but subjects fish to mechanical or human handling (unknown stress) IFC-USAID Fish Passage Workshop - 2016, Nepal

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Baffled Chutes • Category of volitional fishway (i.e., ladder) • Derivative of work by Belgian researcher, G. Denil • Hydraulically function as open channel flumes • Baffles serve as roughness elements • Also know as a “counter flow pass” • Alaska Steeppass and Standard Denil pass are common on the east coast

IFC-USAID Fish Passage Workshop - 2016, Nepal

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Standard Denil Fishways • Baffled-chute type fish ladder • Typically 2-4 foot wide prismatic concrete, steel or wood channels • Applicable to small to large dams and barriers • Moderate capacity for fish passage

IFC-USAID Fish Passage Workshop - 2016, Nepal

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IFC-USAID Fish Passage Workshop - 2016, Nepal

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Alaska Steeppass • • • • • •

Baffled-chute type fish ladder Originally designed for portability Used in Alaska (Ziemer 1962) Applicable to low head dams Low capacity for passage Models A, A40, and C are common on the east coast

IFC-USAID Fish Passage Workshop - 2016, Nepal

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Fishways Technical

Nature‐Like

Upstream

Downstream

Chutes

Pool‐Type

Mechanical

(volitional)

(volitional)

(non‐volitional)

Bypass

Ramps

Step‐Pool

Roughened Channel

Behavioral

Turbines

Guidance Lift

Lock

Trap Physical/ Exclusion

Pool & Weir

Ice Harbor

Vertical Serpentine Slot Bypass

Steeppass

Denil

IFC-USAID Fish Passage Workshop - 2016, Nepal

Transport 8

Pool-Type • • • •

Category of volitional fishway (i.e., ladder) Pool-type ladders have been used for hundreds of years Hydraulically function as overflow weirs Ice Harbor and Vertical slot are common variants

IFC-USAID Fish Passage Workshop - 2016, Nepal

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• Rectangular/V-notch

IFC-USAID Fish Passage Workshop - 2016, Nepal

• Pool and chute

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IFC-USAID Fish Passage Workshop - 2016, Nepal

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• Pools arrayed in stepped channel; includes turning and resting pools • Characteristic vertical slot serves as hydraulic control • Complex hydraulics • Sizing and arrangement of slot and walls is variable; influenced by 1. hydraulics, discharge 2. biological needs of fish

IFC-USAID Fish Passage Workshop - 2016, Nepal

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Ice Harbor Fishway • Pool-type variant • Developed on the Ice Harbor dam on the Snake River • Applicable to medium to high head dams • Successful technology used on west coast

IFC-USAID Fish Passage Workshop - 2016, Nepal

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2 overflow weirs separated by a central baffle wall IFC-USAID Fish Passage Workshop - 2016, Nepal

note aeration and turbulence (east coast specific concerns) 14

Fishways Technical

Nature‐Like

Upstream

Downstream

Chutes

Pool‐Type

Mechanical

(volitional)

(volitional)

(non‐volitional)

Bypass

Ramps

Step‐Pool

Roughened Channel

Behavioral

Turbines

Guidance Lift

Lock

Trap Physical/ Exclusion

Pool & Weir

Ice Harbor

Vertical Serpentine Slot Bypass

Steeppass

Denil

IFC-USAID Fish Passage Workshop - 2016, Nepal

Transport 15

Mechanical Fish Passage • Non-volitional fishways include: • Fish lifts (or elevators) • Fish Locks (rare) • Trap and transport • Mechanical passage moves fish over dams • Little to no energetic cost to fish to ascend • Benefit to alosine biology • Subject to human operations and handling • Many moving parts… and therefore subject to many types of failure!

IFC-USAID Fish Passage Workshop - 2016, Nepal

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Fish Lifts & Fish Locks • • • • • • •

Non-volitional fish passage Applicable to high head dams Hydropower Cost largely independent of height O&M requirement high Passage to wide number of species Common on east coast

IFC-USAID Fish Passage Workshop - 2016, Nepal

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IFC-USAID Fish Passage Workshop - 2016, Nepal

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IFC-USAID Fish Passage Workshop - 2016, Nepal

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Fishways Technical

Nature‐Like

Upstream

Downstream

Chutes

Pool‐Type

Mechanical

(volitional)

(volitional)

(non‐volitional)

Bypass

Ramps

Step‐Pool

Roughened Channel

Behavioral

Turbines

Guidance Lift

Lock

Trap Physical/ Exclusion

Pool & Weir

Ice Harbor

Vertical Serpentine Slot Bypass

Steeppass

Denil

IFC-USAID Fish Passage Workshop - 2016, Nepal

Transport 20

IFC-USAID Fish Passage Workshop - 2016, Nepal

IFC-USAID Fish Passage Workshop - 2016, Nepal

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IFC-USAID Fish Passage Workshop - 2016, Nepal

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Fishways Technical

Nature‐Like

Upstream

Downstream

Chutes

Pool‐Type

Mechanical

(volitional)

(volitional)

(non‐volitional)

Bypass

Ramps

Step‐Pool

Roughened Channel

Behavioral

Turbines

Guidance Lift

Lock

Trap Physical/ Exclusion

Pool & Weir

Ice Harbor

Vertical Serpentine Slot Bypass

Steeppass

Denil

IFC-USAID Fish Passage Workshop - 2016, Nepal

Transport 24

(210‐VI‐NEH, August 2007)

IFC-USAID Fish Passage Workshop - 2016, Nepal

IFC-USAID Fish Passage Workshop - 2016, Nepal

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Questions?

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Hydrology & Fish Passage Design Flows

Brett Towler, Regional Fish Passage Engineer, USFWS IFC-USAID Fish Passage Workshop 2016, Nepal

Fish Migration and Hydrology • Many resident and diadromous fish migrations are triggered by flow and temperature • Results in a limited window for moving fish upstream • delays may impact life history of fish

• High flows in Spring create naturally challenging conditions for fish movement IFC-USAID Fish Passage Workshop 2016, Nepal

Measuring Streamflow • In the U.S. -- USGS Network (approx. 6000 gages in U.S.) • Stream flow collected every 15 minutes (continuous) • Daily average stream flow (m3/sec) required to develop fish passage design flows.

• In Nepal, data may be available from the Ministry of Population & Environment http://www.dhm.gov.np/ IFC-USAID Fish Passage Workshop 2016, Nepal

Flow Duration Curve (FDC) • A plot of flow rate (Q) versus the probability (P) that the flow rate will be exceeded in a specified time interval. • This plot shows the flow rate (Q95) which will be equaled or exceeded 95% of the time.

4 IFC-USAID Fish Passage Workshop 2016, Nepal

Estimating Streamflow at Ungaged Sites Transfers stream flow from a gaged REFERENCE site to a non-gaged TARGET site.

 At Qt  Qr   Ar Qt = flow at target Qr = flow at reference

  

X

At = area of target watershed Ar = area of reference watershed X ~ 1.0

* Assumes target and reference basin are hydrologically similar.

IFC-USAID Fish Passage Workshop 2016, Nepal

We understand there’s link between hydrology and fish movement… how can we use that information to inform the design of fishways?

1.

2.

3.

4.

Definitions Methods Agency Criteria Recommendations

“During development of fish passage facility designs, site specific information is critical for determining the design time frame and river flow conditions.”

-NMFS (2012) Diadromous Fish Passage IFC-USAID Fish Passage Workshop 2016, Nepal

Fish Passage Design Flows or “Fishway Operating Flows�

low IFC-USAID Fish Passage Workshop 2016, Nepal

normal

high

FLOOD

DROUGHT

Refers to the range of stream flow over which a fish passage facility must operate to achieve safe, timely, and effective passage. Outside of this range, it is assumed that fish are not actively migrating or may be able to pass the barrier without the need of a fish passage facility.

Fish Passage Design Flows Fish Passage Flows Fishway Flows Operating Flows Operating Range Flow Capacity Flood Protection Flows “What's in a name? that which we call a design flow by any other name would provide passage”

IFC-USAID Fish Passage Workshop 2016, Nepal

IFC-USAID Fish Passage Workshop 2016, Nepal

• Design flows are important elements of safe, timely, and effective fish passage. • Establishing design flows is typically a first step in fishway design.

1. Mean Flow Indices 2. Return Interval Approach 3. Flow Duration Method

IFC-USAID Fish Passage Workshop 2016, Nepal

Mean Flow Indices • High design flows based on a multiple of annual or monthly average stream flow • Monthly flow depends on target species • Typically select month during peak of migration for diadromous species • 3-4 times annual mean daily flow correlates well with other methods

IFC-USAID Fish Passage Workshop 2016, Nepal

Mean Flow Indices Advantages: • Simple • Does not require FDC or frequency analysis

Disadvantages: • No estimate of frequency of fish passage conditions nor duration of passable conditions

IFC-USAID Fish Passage Workshop 2016, Nepal

Return Interval Approach (Q3d) • High design flow only • Proposed by Katopodis (1992) “Introduction to Fishway Design” • Based on frequency analysis of multiple day storm events that inhibit fish passage  3-day events  log plot  linear regression  10 year RI IFC-USAID Fish Passage Workshop 2016, Nepal

Return Interval Approach (Q3d) Advantages: • Incorporates delay metric (e.g., 3-day) that impairs spawning cycle • Accounts for frequency of events that may impact cohorts (e.g., 10-year) • Adaptable to any combination of delay and frequency

Disadvantages: • 3-day, 10-year produces large flow!

• Basis for 3-day, 10-year is not well established • Not widely accepted by resource agencies IFC-USAID Fish Passage Workshop 2016, Nepal

Q

Flow Duration Method

FDC

• High and low design flows P • Easily illustrated on the project’s flow duration curves (FDC) • Design flows related to historical probability that flows were equaled or exceeded • Method allows one to quantify % of year (or migration period) that fishway (or ZOP) is within operating range.

• Most commonly used method by government resource agencies (e.g., FWS, NOAA, USFS) IFC-USAID Fish Passage Workshop 2016, Nepal

USFWS Low Design Flow, Q95 The design low flow for fishways is the lowest magnitude river discharge during which safe, timely and effective fish passage can be achieved . The Service defines this low flow as the smallest daily average streamflow that is equaled or exceeded 95% of the time during the period when migrating fish are normally present at the site.

Q

FDC

Q95 95% IFC-USAID Fish Passage Workshop 2016, Nepal

P

USFWS High Design Flow, Q05 The design high flow for fishways is the highest magnitude river discharge during which safe, timely and effective fish passage can be achieved . The Service defines this low flow as the smallest daily average streamflow that is equaled or exceeded 5% of the time during the period when migrating fish are normally present at the site.

Q

FDC

Q05

5% IFC-USAID Fish Passage Workshop 2016, Nepal

P

Q

MIGRATION PERIOD V. ANNUAL annual FDC (i.e., Jan – Dec) FDC typical of fish migration periods (e.g., mahseer movement in July, Aug, and Sep) typical shift

100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

IFC-USAID Fish Passage Workshop 2016, Nepal

P

Recommend using a min. of 10 years of data to calculate FDC

OPERATING RANGE

Q

OPERATING DURATION

QH

90% of the Migration Period (or year)

QL 100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

IFC-USAID Fish Passage Workshop 2016, Nepal

P

Q

POWERHOUSE HYDRAULIC CAPACITY typical hydro project ~ 15-35% Project controls river

Spill (attraction to PH)

(false attraction?)

100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

IFC-USAID Fish Passage Workshop 2016, Nepal

P

Example Q1 – powerhouse hydraulic capacity Q2 – flood gates open

Q no pass false attract to gates attract to bypass

QH 10% of the time, fish are attracted to PH, spillway and flood gates (if distinct from spillway) Q2

15% of the time, fish are attracted to PH and bypass (below spillway)

Q1

65% of the time, fish are attracted to PH only

attract to PH no pass

QL 100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

IFC-USAID Fish Passage Workshop 2016, Nepal

P

HIGH DESIGN FLOW

DAM SPILLS, BYPASS FLOW

PASSAGE OCCURS UNDER ADVERSE LEVELS OF COMPETING FLOWS AND FALSE ATTRACTION

AT FLOWS LESS THAN STATION CAPACITY, TURBINE DISCHARGE DOMINATES RIVER DOWNSTREAM SEASON

NOMINAL FISH PASSAGE

STATION CAPACITY

PASSAGE OCCURS UNDER LOW TO MODERATE COMPETING FLOWS

LOW DESIGN FLOW MIN

J F M A M J J A S O N D

HYDROLOGY DURING FISH MOVEMENT

BELOW OPERATING RANGE 5%

~30%

95%

EXCEEDANCE PROBABILITY & DESIGN FLOWS

IFC-USAID Fish Passage Workshop 2016, Nepal

WATER SURFACE ELEVATION

STAGE‐ DISCHARGE RELATION

OPERATING RANGE OF FISHWAY

FISHWAY OPERATING RANGE

ABOVE OPERATING RANGE

FLOW

FLOW

FLOW

MAX

Design Flows • Range represents the entire river flow during the fish passage season • not the discharge through the fishway!

• Hydrology is dependent on migration season of target species • e.g., Atlantic salmon, ME : April 15 to Oct 31 • e.g., American shad, MA : April 1 to July 15

• Allows for passage during 90% of the migration season • Fishway should be designed to be operable over this range (actual operations may differ) IFC-USAID Fish Passage Workshop 2016, Nepal

IFC-USAID Fish Passage Workshop 2016, Nepal

Questions?

IFC-USAID Fish Passage Workshop 2016, Nepal

Water Velocity & Fish Swimming Capacity

Brett Towler, Regional Fish Passage Engineer, USFWS IFC-USAID Fish Passage Workshop-2016, Nepal

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Hydraulic Design of Fishways There are myriad considerations in the design of a fish lift or ladder. The primary hydraulic parameters include: 1. Flow 2. Depth 3. Width 4. Velocity Fish swimming capacity must be considered in the hydraulic design of any fishway!

IFC-USAID Fish Passage Workshop-2016, Nepal

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Flow • Flow is based upon discharge at the hydraulic control in the fishway • Hydraulic control can a point (e.g., transitional flow over a weir) or a length of a channel (e.g., uniform flow in a channel) • Over the course of a fishway, flow may have multiple controls, withdrawals or supplemental flow

Px  0 pressure driven

varied flow

d 0 dx

IFC-USAID Fish Passage Workshop-2016, Nepal

gx  0 gravity driven

steady state

d 0 dt

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Open Channel Flow • Steady, uniform, 1D OCF: Manning’s Equation

2 1 1.486 3 Q AR S f 2 n

Roughness coefficient warrants close scrutiny!

IFC-USAID Fish Passage Workshop-2016, Nepal

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Weir Flow • Steady, rapidly varied, 1D flow: Weir Formula

Q  CLH

3/ 2

Weir height, shape, approach velocity, and lateral contraction dramatically effect discharge!

IFC-USAID Fish Passage Workshop-2016, Nepal

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Velocity • Currents with adequate velocity are necessary at entrances to attract fish (i.e., induce rheotactic response) • High velocities may impede fish movement through ladders or in the project’s zone of passage.

attract

IFC-USAID Fish Passage Workshop-2016, Nepal

impede

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Swimming Speeds • Conventional approach is to conceptualize a 3-speed model based on utilization of red and white muscle tissue. • Fatigue times are associated with these 3 speeds.

IFC-USAID Fish Passage Workshop-2016, Nepal

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Burst or Dart or Sprint Speed …the swim speed that a fish can maintain for seconds

• Burst speed engages anaerobic white muscle tissues • Bell (1990) suggests can be maintained for 5-10 sec.; Bain (1999) 2-3 sec.; Beamish (1978) < 20 sec.

• Speed used for predator avoidance or feeding; in fishways, use to ascend weir crests • For fish passage design, velocities should be kept below VB for the weakest target species at all times ஻

௉

IFC-USAID Fish Passage Workshop-2016, Nepal

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Prolonged (or Sustained*) Speed …the swim speed that a fish can maintain for minutes

• Prolonged speed engages both red & white muscle tissues • Bain (1999) suggests speed can be maintained for 5-8 min.; Beamish (1978) suggests 20 sec. to 200 min.

• Critical swim speed, Ucrit, is a sub-category of prolonged speed measured by Brett (1964) • For fish passage design, VP can be used in conjunction with t to estimate travel distance, D, before fatigue ିଵ

௉

ିଵ

௚

௪

௚ IFC-USAID Fish Passage Workshop-2016, Nepal * There are contradictory definitions of sustained swim speed.

௉

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Cruising or Sustained Speed …the swim speed that a fish can maintain for hours

• Cruising speed engages aerobic red muscle tissues • Speed used for extended periods of travel at low speeds • Influenced by temperature, oxygen; Bell (1990) suggested swim speeds reduced by 50% at temp. extremes • For fish passage design, VC should be used for transport flumes, holding pools, etc. ஼

IFC-USAID Fish Passage Workshop-2016, Nepal

௉

஻

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Example: Tor putitora Assume an adult mahseer of 50 cm in body length (BL). In the absences of species-specific data, estimate its swimming capacity: Burst speed (seconds)

஻

Prolonged speed (minutes) Cruising speed (hours) IFC-USAID Fish Passage Workshop-2016, Nepal

௉ ஼ 11

Example: Tor putitora Assume an adult mahseer of 50 cm in body length (BL). In the absences of species-specific data, estimate its swimming capacity: Fishways should never expose this fish to water velocities of this magnitude!

஻

Appropriate for short durations (e.g., traveling through a vertical slot) OK for movement through flumes and long conveyance channels IFC-USAID Fish Passage Workshop-2016, Nepal

௉ ஼ 12

Swim Speed v. Water Velocity • Water velocity in fishway design must be evaluated with the distance the fish must cover and possible fatigue issues.

200‐ft long roughened rock ramp NLF might be design to allow sustained speed for a weak riverine fish, 1.0 m/s For that same fish, a pool‐and‐weir ladder might be designed for the combination of near burst speed (over weirs) followed by prolonged speed (in pools), 0.3 m/s v. 2.0 m/s IFC-USAID Fish Passage Workshop-2016, Nepal

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Other Tools for Estimating Swimming Capabilities Haro et al. (2004) – Survivorship model * Castro-Santos (2005) – Fatigue model * * for U.S. east coast species only (may serve as surrogate for other species?)

Behlke (1991) – Work Energy model I developed a computer implementation of this model that I’m willing to share! (email me) IFC-USAID Fish Passage Workshop-2016, Nepal

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Water Velocity and AWS Diffusers  Maximum AWS diffuser point-velocity criterion set to prevent confusion in fish USFWS R5  Vertical/wall diffusers, V ≤ 0.15 m/s

Criteria:

 Horizontal/floor diffusers, V ≤ 0.3 m/s horizontal (floor)

horizontal

vertical (wall)

vertical IFC-USAID Fish Passage Workshop-2016, Nepal

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Water Depth • Providing sufficient depth allows fish to swim normally and may alleviate any adverse behavioral reaction to shallow water USFWS R5 Criteria: 2 times the fishes body depth (other depth criteria may apply)

IFC-USAID Fish Passage Workshop-2016, Nepal

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Width • In a natural environment, fish are accustomed to moving in an open river.

• Narrow opening many inhibit swimming ability, injure fish or elicit a rejection response.

• especially problematic for schooling fish

• Fishways, by necessity, concentrate flow and narrow openings accelerate velocity!

Vertical slot openings less than or equal to 30 cm, allow clupeids to pass, but fish may injure and abrade themselves on concrete wall.

IFC-USAID Fish Passage Workshop-2016, Nepal

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Width â&#x20AC;˘ In trapping scenarios, narrow widths may serve to prevent fish from exiting the fishway.

V-traps maintained at ~ 0.3 to 0.6 m IFC-USAID Fish Passage Workshop-2016, Nepal

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Streaming and Plunging Flow • Plunging Flow • • •

Flow plunges downward into pool Occurs with lower head on weir crest Creates a reverse-rolling hydraulic

• Streaming Flow • • • •

Occurs with higher flows/higher heads Can be induced by decreasing longitudinal pool length Generally accepted that streaming flow regime is preferred for alosines Creates a forward-rolling hydraulic

IFC-USAID Fish Passage Workshop-2016, Nepal

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Streaming Flow

IFC-USAID Fish Passage Workshop-2016, Nepal

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 Head ~16” +

Streaming Flow

IFC-USAID Fish Passage Workshop-2016, Nepal

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 Head ~16” +  Surface flow

Streaming Flow

IFC-USAID Fish Passage Workshop-2016, Nepal

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 Head ~16” +  Surface flow  Forward roller

Streaming Flow

IFC-USAID Fish Passage Workshop-2016, Nepal

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 Head ~16” +  Surface flow  Forward roller  Fish aligned U/S

Streaming Flow

IFC-USAID Fish Passage Workshop-2016, Nepal

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Plunging Flow

IFC-USAID Fish Passage Workshop-2016, Nepal

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 Head 15” or less

Plunging Flow

IFC-USAID Fish Passage Workshop-2016, Nepal

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 Head 15” or less  Diving flow

Plunging Flow

IFC-USAID Fish Passage Workshop-2016, Nepal

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 Head 15” or less  Diving flow  Reverse roller

Plunging Flow

IFC-USAID Fish Passage Workshop-2016, Nepal

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 Head 15” or less  Diving flow  Reverse roller  Fish aligned D/S

Plunging Flow

IFC-USAID Fish Passage Workshop-2016, Nepal

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Video 2 Plunging flow in a pool and weir fishway https://www.youtube.com/watch?v=A7K90e4pu3o

IFC-USAID Fish Passage Workshop-2016, Nepal

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Video 3 Streaming flow in a pool and weir fish ladder https://www.youtube.com/watch?v=H8EVejJMBmQ

IFC-USAID Fish Passage Workshop-2016, Nepal

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plunging • • •

streaming

Fish that leap (e.g., salmonids) are not inhibited by plunging flow.

Fish that do not leap may be confused by plunging flow.

Streaming flow is generally preferred.

IFC-USAID Fish Passage Workshop-2016, Nepal

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Streaming Flow Index* • On average, transition occurs around  = 0.25 • For design,  > 0.31 to ensure streaming flow



Qw S 0bw L p

3

2

g

where: Qw is the flow over weir S0 is the slope Bw is width of the weir LP is length of the weir g is gravitational acceleration

“Plunging and Streaming Flows in Pool and Weir Fishways”, Rajaratnam et al. (1988)

*caution, this equation was developed for simple pool and weir only!

IFC-USAID Fish Passage Workshop-2016, Nepal

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Hydraulic Design “Take Home” Messages • Fish swimming capacity should drive hydraulic design fishway and initial conceptual plans • Resource agencies have identified important hydraulic relationships that influence fish passage • Good design incorporates many different, often conflicting, parameters…

• Approach the hydraulic design of fishways with the same rigor as any other hydraulic structure!

IFC-USAID Fish Passage Workshop-2016, Nepal

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Questions?

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IFC-USAID Fish Passage Workshop-2016, Nepal

Attraction: Flow, Velocity, and Location

Brett Towler, Regional Fish Passage Engineer, USFWS IFC-USAID Fish Passage Workshop-2016, Nepal

“Siting, design, and effective attraction flow are important features of the fishway entrance, and the overall ability of the fishway to effectively move fish past the barrier without delay.” ‐ NMFS (2012), Diadromous Fish Passage

“[attraction flow] emanates from a fishway entrance with sufficient velocity and in sufficient quantity and location to attract upstream migrants into the fishway.” ‐ NMFS (2011), Anadromous Salmonids Passage Facility Design IFC-USAID Fish Passage Workshop-2016, Nepal

2

Rheotaxis

flow

flow IFC-USAID Fish Passage Workshop-2016, Nepal

negative positive rheotaxis rheotaxis

â&#x20AC;¢ Rheotaxis is a form of taxis (i.e., directed behavior) seen in many aquatic organisms (e.g., fish) whereby they will orient or respond to a current of water.

3

• Sometimes attraction to the fishway entrance is obvious…

• And other times… not!

IFC-USAID Fish Passage Workshop-2016, Nepal

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Attraction Flow (Upstream) • Attraction flow must be in sufficient quantify to create a hydraulic cue (for fish) over a broad region of the tailrace (or wetted area behind the stream barrier).

• Attraction flow must provide this cue in the presence of a competing flows (e.g., spill, powerhouse discharge, cooling water discharge, flood gates) • Most types of fishways do not discharge enough flow to adequately attract fish into the entrance of the fishway when competing flows are significant.

• • • •

Steeppass (22” wide) 4-ft wide Denil 16-ft wide Half Ice Harbor 8-ft wide by 10-ft long V-slot IFC-USAID Fish Passage Workshop-2016, Nepal

3 to 10 cfs 16 to 35 cfs 30 to 50 cfs 10 to 55 cfs

auxiliary or supplemental flow needed?

5

Competing Flow …or False Attraction • At many dams, river flows are passed over, through, and around various machines and water control structures.

• These structures may attract (or dissuade) fish and thus, compete with the directional cues created by fishways.

• Sources of false attraction include: • • • • •

spillways turbines/powerhouse flood gates trash/log sluices cooling water returns

IFC-USAID Fish Passage Workshop-2016, Nepal

attraction flow = fishway discharge + auxiliary water 6

Competing Flow Examples

IFC-USAID Fish Passage Workshop-2016, Nepal

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How much is enough?

• In the absence of the dam or natural falls, the entire river directs the fish upstream, but due to competing demands for the water attraction flow is limited.

Agency/Author

Recommendation

NMFS Columbia, Snake Rivers

total attraction flow (for upstream fishways) must be a minimum of 3% of mean annual river flow

Larinier (2000)

recommends attraction flow 1 to 1.5% of high design flow (5% on fish season FDC) for larger rivers

NMFS (2011), NW Region

5 to 10% of high design flow for streams with mean annual flows in excess of 1,000 cfs; for smaller streams use up to 100% of flow

Larinier (2000)

recognizes that attraction flow should be at least 1 to 5% of all competing flows (this includes spillway discharge!)

USFWS NE Region

minimum attraction flow at hydro projects is 3 to 5% of station hydraulic capacity (approx. 30% on annual FDC)

Larinier, M. 2000. Dams and Fish Migration. Contributing paper to the World Commission on Dams. (http://www.dams.org/) NMFS. 2011. Anadromous Salmonid Passage Facility Design. National Marine Fisheries Service‐Northwest Region. (www.nwr.noaa.gov) July 2011.

IFC-USAID Fish Passage Workshop-2016, Nepal

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Auxiliary Flow Systems (AWS) • Attraction flow is augmented (or supplemented) with Auxiliary Flow Systems (AWS) • This requires a separate, often more complex, water conveyance system to add water immediately upstream from the entrance • Flow is diffused through grating on the floor, side walls, or upstream from the hopper (in the case of a lift)

IFC-USAID Fish Passage Workshop-2016, Nepal

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AWS Example: USFWS NE Region

minimum attraction flow at hydro projects is 3 to 5% of station hydraulic capacity

8-ft wide by 10-ft long VSF

10 to 55 cfs

• if a vertical slot is chosen with a normal flow of 30 cfs at a site that has a station capacity of 7,000 cfs • then 30 cfs only represents 0.4% of station capacity • therefore 2.6% or 182 cfs needs to be supplemented via an AWS (auxiliary water system) IFC-USAID Fish Passage Workshop-2016, Nepal

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Floor Diffuser SOLID PANELS

OPEN AREA REPRESENTING GRATED SECTION

FLOW DIRECTION (EVENLY DISTRIBUTED THROUGH TIMBER DIFFUSER BAFFLES; TURNING VANES)

• Max. velocity 0.3 m/s • Uniform velocity distribution • No aeration and turbulence IFC-USAID Fish Passage Workshop-2016, Nepal

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IFC-USAID Fish Passage Workshop-2016, Nepal

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IFC-USAID Fish Passage Workshop-2016, Nepal

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IFC-USAID Fish Passage Workshop-2016, Nepal

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Wall Diffuser • Max velocity 0.15 m/s • Uniform velocity distribution

Fishway Entrance

Wall Diffuser AWS Pipe

IFC-USAID Fish Passage Workshop-2016, Nepal

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Attraction Velocity (i.e., Entrance Jets)

• While flow describes the quantity of discharge (i.e., cubic feet per second) needed to achieve attraction, velocity must be considered carefully as well.

• In general, velocity must be higher than the ambient current in tailwater area, yet lower than the burst speed of the target species.

• USFWS experience suggests that most fishways should provide an entrance jet velocity of 1.2 to 1.8 meters per second to properly attract the suite of east coast anadromous species (e.g., alosines, salmonids) * * Optimal entrance velocities should be based on local target species behavior and swimming capability.

IFC-USAID Fish Passage Workshop-2016, Nepal

16

Attraction Velocity and Flow!

• Produce enough momentum to penetrate the receiving waters and attract fish by creating a hydraulic cue (well defined attraction jet) • Should not create a velocity barrier • Typically cannot achieve appropriate momentum without proper attraction flow

IFC-USAID Fish Passage Workshop-2016, Nepal

17

Attraction Velocity and Flow!

Meets velocity criteria but not flow criteria

Meets velocity and flow criteria

IFC-USAID Fish Passage Workshop-2016, Nepal

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Entrance Location • Generally, the entrance should be located at the most upstream point below the barrier (e.g., dam) and situated within a slow velocity, low turbulence zone

IFC-USAID Fish Passage Workshop-2016, Nepal

19

Entrance Location • Sometimes locating the fishway at the most upstream point doesn’t appropriately attract fish due to confusing hydraulics • In this case locating the fishway entrance downstream of a highly turbulent area may be necessary

Entrance

Attraction Jet? IFC-USAID Fish Passage Workshop-2016, Nepal

20

• CFD (computational fluid dynamics) and fish telemetry studies can inform the location of a fishway entrance • Which side of tailrace should entrance be located?

• How far downstream of the barrier?

• Are 2 entrances necessary?

• Is a training wall required to protect the low velocity zone?

IFC-USAID Fish Passage Workshop-2016, Nepal

21

• Downstream passage is a critical component of a fully connected river. Adult migrants go up, juveniles must come down (and some adults too).

IFC-USAID Fish Passage Workshop-2016, Nepal

22

Attraction Flow (Downstream) • Downstream bypass must create a hydraulic signal strong enough to attract fish to one or multiple entrances in the presence of competing flows, in particular turbine intakes • Service criteria calls for DS bypass intake(s) to have a minimum attraction discharge:

Up to 4% to 5% of station hydraulic capacity (not to be confused with average daily generation!)

A new powerhouse with a hydraulic capacity of 7,800 cfs should maintain a DS bypass entrance portal(s) flow of 312 to 390 cfs IFC-USAID Fish Passage Workshop-2016, Nepal

23

Questions?

IFC-USAID Fish Passage Workshop-2016, Nepal

24

Turbulence, Aeration and the Energy Dissipation Factor (EDF)

Brett Towler, Regional Fish Passage Engineer, USFWS IFC-USAID Fish Passage Workshop-2016, Nepal

1

Hydraulics and Fish Movement • Flow, depth, width and velocity have been presented as the primary hydraulic parameters for fishways; however…

• The phenomena of turbulence and air entrainment can influence fish movement.

???

attract IFC-USAID Fish Passage Workshop-2016, Nepal

impede 2

Turbulence can have an adverse effect…

• greatly elevated levels of shear and turbulence may be injurious to fish ‐ Neitzel et al., 2000 • clupeids (shad, herring) were much more susceptible to shear stresses ‐ Turnpenny et al., 1992 • turbulence can influence the startle response of fish ‐ Odeh et al. (1992) • minimizing turbulence and air entrainment within fishways is generally considered advantageous for fish passage ‐ Larinier and Travade, 1992 IFC-USAID Fish Passage Workshop-2016, Nepal

3

…but fish live in a turbulent environment.

• hydraulic shear stress and turbulence are interdependent natural hydraulic phenomena that are important to fish ‐ Odeh et al., 1992 • turbulence and vortices can be either beneficial or detrimental to fish ‐ Hockley et al., 2013 • the appropriate reaction to turbulence may promote movement of migratory fish ‐ Coutant, 1998

IFC-USAID Fish Passage Workshop-2016, Nepal

4

Turbulence and Air Entrainment • Commonly misunderstood!

• Turbulence and aeration are separate phenomena that often occur simultaneously when high energy flows occur near the water-air interface

“Big whorls have little whorls That feed on their velocity, And little whorls have lesser whorls And so on to viscosity.”

- Lewis Richardson IFC-USAID Fish Passage Workshop-2016, Nepal

5

How to Describe Turbulence?

• Unlike laminar flow, turbulent flow cannot be described analytically; its often described statically and by observable phenomena… boundary layer development scale of eddies velocity fluctuations IFC-USAID Fish Passage Workshop-2016, Nepal

6

Please, please, please… stop saying fish only want “laminar” flow!

You probably mean: • • • • • • • •

clear flow, no whitewater non‐aerated, no bubbles hydraulically smooth low energy flow low velocity flow stable discharge laminar boundary flow no (perceivable) eddies IFC-USAID Fish Passage Workshop-2016, Nepal

turbulent flow can be all of these things!

7

Predicting Turbulent Flow in Open Channels • Reynolds Number

RE 

VD



Laminar: RE < 500

IFC-USAID Fish Passage Workshop-2016, Nepal

V is velocity D is hydraulic depth  is viscosity

Turbulent: RE > 1000

8

Common misconception that fish passage is dependent on laminar conditions.

IFC-USAID Fish Passage Workshop-2016, Nepal

9

Depth of flow in river (ft)

River Velocity (ft/s) IFC-USAID Fish Passage Workshop-2016, Nepal Reynolds # as a predictor of turbulent & laminar flow in a wide river 10

Turbulence • Rivers are naturally turbulent environments • Fish are accustomed to turbulence • Extreme turbulence has been shown to impact fish swimming ability • Scale of turbulent eddy is an important factor • Turbulence predicted by the Reynolds Number • In general, we design fishways for low to moderate levels of turbulence IFC-USAID Fish Passage Workshop-2016, Nepal

11

Aeration or Air Entrainment â&#x20AC;˘ Entrained air can dissuade fish from entering into a fishway or fish passage structure; it should be minimized â&#x20AC;˘ Unnecessary hydraulic jumps in channels, underdesigned AWS diffusers, and plunging flow are common sources of aeration and bubbles.

IFC-USAID Fish Passage Workshop-2016, Nepal

12

Accounting for Turbulence and Air Entrainment in the Design of Fishways • While many statistical measures of turbulence exist (e.g., eddy viscosity), they are ill‐suited as design equations.

• Similarly, direct measures of air entrainment can be made (e.g., bulking), but don’t lend themselves to fishway design.

Volumetric power dissipation, or the rate at which flow energy is lost in a volume of water, correlates well to observations of turbulence and air entrainment.

IFC-USAID Fish Passage Workshop-2016, Nepal

13

Volumetric Power Dissipation and the EDF • Energy Dissipation Factor (EDF), estimates turbulence and aeration • Measure of the volumetric rate of energy dissipation in a pool, chute or stream reach.

QH EDF  VP

where: Q is the flow through the fishway H is the head drop per pool VP is the volume of the pool  is unit wt. of water

*many other forms of the EDF exist; this is the most common version for step-pool fishways IFC-USAID Fish Passage Workshop-2016, Nepal

14

Energy Dissipation Function (EDF)

QH EDF  VP

(ft-lbf/s/ft3)

• criterion for turbulence in step-pool technical fishways • correlates to macro turbulence and aeration IFC-USAID Fish Passage Workshop-2016, Nepal

salmon shad

15

IFC-USAID Fish Passage Workshop-2016, Nepal

Fishway Dimensions and EDF  Various EDF recommendations for species, life stages, and fishway components exist  Supported by numerous agency guidelines and peer‐reviewed literature  Primary design parameter for sizing pools (may have more general application)  Along with biological capacity (next module!), EDF is a competing constraint on fishway size IFC-USAID Fish Passage Workshop-2016, Nepal

Questions?

IFC-USAID Fish Passage Workshop-2016, Nepal

18

Pool-Type Fishways

Brett Towler, Regional Fish Passage Engineer, USFWS IFC-USAID Fish Passage Workshop-2016, Nepal

1

Fishways Technical

Nature‐Like

Upstream

Downstream

Chutes

Pool‐Type

Mechanical

(volitional)

(volitional)

(non‐volitional)

Bypass

Ramps

Step‐Pool

Roughened Channel

Behavioral

Turbines

Guidance Lift

Lock

Trap Physical/ Exclusion

Pool & Weir

Ice Harbor

Vertical Serpentine Slot Bypass

Steeppass

Denil

IFC-USAID Fish Passage Workshop-2016, Nepal

Transport

2

Pool-Type Fishways 1.

2.

3.

4.

Geometry and Layout Discharge Characteristics Limitations Variants

IFC-USAID Fish Passage Workshop-2016, Nepal

3

Overview • Pool-type fishways are one of the oldest fish passage technologies • Fundamentally different from baffled-chute types: 1. Baffled-chutes approximate open channel flow 2. Pool-types characterized by sequential step-pools

• Pool-types can range from small to very large • Biological capacity to pass fish is large • Subject to operational challenges

IFC-USAID Fish Passage Workshop-2016, Nepal

4

IFC-USAID Fish Passage Workshop-2016, Nepal

5

flat, quiescent, pool

transitional flow over weir crest

contracted weir crest

each pool divides the total barrier height into 15 to 45 cm steps or drops 6

IFC-USAID Fish Passage Workshop-2016, Nepal

notches provide passage during low flow

hydraulic design of culverts for fish passage 7

IFC-USAID Fish Passage Workshop-2016, Nepal

Hydraulics of a Weir • Discharge is proportional to the lateral length of the crest and to the 3/2 power of the head (water) on the crest.

Q  CLH

3

2

• In turn, velocity of the flow (jet) over the crest is proportional to the root of the head (water) on the crest.

V H Why is this important?

IFC-USAID Fish Passage Workshop-2016, Nepal

8

As water over the crest increases… so does the velocity.

• Consider a fishway designed for river herring with a burst speed of 1.8 m/s; fish must ascend through a 1.2‐m‐long jet of water.

Head (m)

Water Velocity (m/s)

Fish Swim Speed (m/s)

Ground Speed (m/s)

Time to Ascend Pool (sec)

0.15

0.65

1.52

0.87

1.4

0.3

0.91

1.52

0.61

2

0.45

1.13

1.52

0.39

3.1

0.6

1.28

1.52

0.24

5

0.75

1.43

1.52

0.09

13.3

0.9

1.58

1.52

-0.06

NEVER

With as little a 0.5m over the crest, the velocities being to challenge the endurance of smaller species!

IFC-USAID Fish Passage Workshop-2016, Nepal

9

Limitations on Pool & Weirs • Burst speed is not the only consideration.

Fatigue plays an important role.

• Generally, pools should be designed with a drop of 0.3 m or less.

• For large streams or rivers, biological capacity and turbulence requirements often require pools 3‐meters long or greater.

– 0.3 m drop/3 m pool = slope of 10% For a hydropower project with 20 meters of head, this typically requires a pool & weir fishway of 200 meters or greater!

IFC-USAID Fish Passage Workshop-2016, Nepal

10

Limitations on Pool & Weirs • Velocity requirements limit water over crest, but the upper pool in the fishway must connect to the HW. – P&W cannot accommodate HW fluctuations!

• Design is further constrained by: – – – – –

Capacity of fishway Turbulence Transience, flow development Streaming and plunging flows Depth of flow

IFC-USAID Fish Passage Workshop-2016, Nepal

…issues addressed by Ice Harbor, Serpentine, and Vertical Slot designs

11

Ice Harbor Fishway • Pools & weir modification • eliminate transience • promote flow development • provide resting areas

• Applicable to medium to high head dams • Successful technology used on U.S. west coast • Scalability to other species a concern • Streaming flow (hydraulic) concerns IFC-USAID Fish Passage Workshop-2016, Nepal

12

South Fish Ladder, Ice Harbor Dam IFC-USAID Fish Passage Workshop-2016, Nepal

13

central Ushaped baffle

two weir crests note rectangular pool shape IFC-USAID Fish Passage Workshop-2016, Nepal

14

ICE HARBOR STANDARD DIMENSIONS W

10’

11’

12’

13’

14’

16’

18’

20’

25’

BW

3’ – 1”

3’ – 5”

3’ – 9”

4’ – 1”

4’ – 4”

5’ – 0”

5’ – 8”

6’ – 3”

7’ – 10”

BB

3’ – 10”

4’ – 2”

4’ – 6”

4’ – 10”

5’ – 4”

6’ – 0”

6’ – 8”

7’ – 6”

9’ – 4”



1’ – 10"

2’ – 0”

2’ – 3”

2’ – 5”

2’ – 7”

3’ – 0”

3’ – 0”

3’ – 0”

3’ – 0”

AO

12” x 12”

13” x 13”

14” x 14”

15” x 15”

16” x 16”

18” x 18”

18” x 18”

18” x 18”

18” x 18”

ICE HARBOR DESIGN RATIOS

.

tw

2 Bw

2 2’

2

W HO is the head on the orifice in feet

A0

BB

HW is the head on the weir crest in feet QO is the discharge though each orifice in cfs

P

QW is the discharge over each weir crest in cfs



†

†

L 9

†

Q is the total discharge through the fishway in cfs

1 10

U.S. Fish and Wildlife Service criteria

IFC-USAID Fish Passage Workshop-2016, Nepal

S0

0.86

0.68

2 2 3

two weir crests

central baffle IFC-USAID Fish Passage Workshop-2016, Nepal

submerged orifices 16

Ice Harbor Hydraulics • Oscillations/Transience reduced by central baffle • Discharge – Sum of flow through all orifices and over all weirs – Typically 2 weirs, 2 orifices in an Ice Harbor

• Velocity – Orifices present the greater velocity challenge

• Turbulence (EDF) • Streaming/Plunging Regimes 17

IFC-USAID Fish Passage Workshop-2016, Nepal

Vertical Slot & Serpentine Fishways • Pool-type fishways • Different from Pool & Weir, Ice Harbor and other fishways with weir crests • Vertical slot serves as hydraulic control • Primary advantage is ability to accommodate large swings in headpond 18

IFC-USAID Fish Passage Workshop-2016, Nepal

vertical slot and serpentine fishways IFC-USAID Fish Passage Workshop-2016, Nepal

19

vertical slot fishways IFC-USAID Fish Passage Workshop-2016, Nepal

20

single slot design IFC-USAID Fish Passage Workshop-2016, Nepal

21

dual slot design IFC-USAID Fish Passage Workshop-2016, Nepal

22

Vertical Slot Geometry • Geometry influences discharge, velocity, turbulence and other hydraulic parameters • Some vertical slot designs have been standardized • e.g., Rajaratnum, Wu, Katopodis

• Non-standard designs should be calibrated with physical models • energy dissipation and flow development can result in flow instabilities

IFC-USAID Fish Passage Workshop-2016, Nepal

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Vertical Slot Model in Flume

IFC-USAID Fish Passage Workshop-2016, Nepal

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IFC-USAID Fish Passage Workshop-2016, Nepal

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IFC-USAID Fish Passage Workshop-2016, Nepal

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ideo 4 V Vertical Slot Fish Ladder https://www.youtube.com/watch?v=AotJy2lrYZ8

IFC-USAID Fish Passage Workshop-2016, Nepal

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28

IFC-USAID Fish Passage Workshop-2016, Nepal

10 b

8b

4.8 b

um : max velocity (m/s) h: drop per pool (m)

2b

0.17 b

0.49 b 1 3

*

3.77

1.11

Q: discharge through ladder (m3/s) y0 : depth in pool (m) b: slot width (m) * Design 1 from: Rajaratnam, Van der Vinee, and Katopodis (1986) S0: slope (m/m)

Hydraulics of Vertical Slot Fishways, J. Hydr Engrg. 112(10)

IFC-USAID Fish Passage Workshop-2016, Nepal

45o

0.49 b

1.6 b

IFC-USAID Fish Passage Workshop-2016, Nepal

30

Vertical Slot Summary • “State-of-the-art” fish ladders • Accommodates large fluctuations in HW • Hydraulics are very diverse and depend on geometry • Flow pattern and dimensions influence fish behavior, swimming ability, and ascend rate • Standard design geometries exist; non-standard geometries should be modeled first!

IFC-USAID Fish Passage Workshop-2016, Nepal

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Vertical Slot Summary (cont.)

• Medium slopes (4% to 10%) • Applicable to low and medium head dams • Turning pools may be unnecessary for resting (required for site layout only?)

• Velocities through slots should be less than burst speeds of target species • Slot width should be significantly larger than target species • High energy dissipation characteristics IFC-USAID Fish Passage Workshop-2016, Nepal

32

Questions?

33

IFC-USAID Fish Passage Workshop-2016, Nepal

Fish Lifts

Brett Towler, Regional Fish Passage Engineer, USFWS

IFC-USAID Fish Passage Workshop-2016, Nepal

1

IFC-USAID Fish Passage Workshop-2016, Nepal

2

Fishways Technical

Nature‐Like

Upstream

Downstream

Chutes

Pool‐Type

Mechanical

(volitional)

(volitional)

(non‐volitional)

Bypass

Ramps

Step‐Pool

Roughened Channel

Behavioral

Turbines

Guidance Lift

Lock

Trap Physical/ Exclusion

Pool & Weir

Ice Harbor

Vertical Serpentine Slot Bypass

Steeppass

Denil

IFC-USAID Fish Passage Workshop-2016, Nepal

Transport

3

Fish Lift (or Elevator) • Along with locks and T&T, lifts are non-volitional fishways • In wide use on the east coast since 1980s • Suitable for fish that struggle ascending pools or are limited energetically or by life history 4

IFC-USAID Fish Passage Workshop-2016, Nepal

Fish Lifts 1. Layout 2. Major Components • • • •

Entrance Lower Flume Lift Tower Upper Flume

3. Concerns 4. Applications IFC-USAID Fish Passage Workshop-2016, Nepal

5

Video 5 Fish Li https://www.youtube.com/watch?v=uO6iRzxkm‐w

IFC-USAID Fish Passage Workshop-2016, Nepal

6

IFC-USAID Fish Passage Workshop-2016, Nepal

7

IFC-USAID Fish Passage Workshop-2016, Nepal

8

Lower Flume (Lower Lift) • Section of a fish lift that includes the entrance, entrance channel, Auxiliary Water System (AWS), crowder and the hopper pit; typically invert is 1.2 m below low TW.

Lift Tower • Vertical (or sloped) steel structure which serves as the elevator lift; provides track for vertical movement of the hopper (or bucket) to transport fish from Lower Flume to Upper Flume.

Upper Flume (Upper Lift) • Section of a fish lift that includes the exit, exit flume, transfer chute, and typically a counting room; typically at grade with HW. IFC-USAID Fish Passage Workshop-2016, Nepal

9

*most lifts include 90o or 180o turns; straight lift shown for illustrative purposes IFC-USAID Fish Passage Workshop-2016, Nepal

10

*floor diffusers (for AWS) are more common than side diffusers (shown here) IFC-USAID Fish Passage Workshop-2016, Nepal

11

*sizing the AWS properly ensures that turbulence and air entrainment are minimized IFC-USAID Fish Passage Workshop-2016, Nepal

12

Auxiliary Water System (AWS) Attraction Flow Through = Flow Fishway

+

AWS

• Typically, ladders don’t discharge enough water to compete with false attraction from PH, spillway • Lifts don’t discharge any flow • AWS or supplemental flow augments flow through the fishway • AWS can be gravity driven (as shown) or delivered through submerged pumps in TW 13

IFC-USAID Fish Passage Workshop-2016, Nepal

*velocities through diffusers must be low; higher velocities can confuse fish!

IFC-USAID Fish Passage Workshop-2016, Nepal

14

*proper attraction has 3 components: location, flow and velocity; entrance gates are used to accelerate attraction jet IFC-USAID Fish Passage Workshop-2016, Nepal

15

*once fish enter the holding pool, they are mechanically crowded above the hopper IFC-USAID Fish Passage Workshop-2016, Nepal

16

*water is directed through the rear diffuser and over the hopper to motivate fish to swim upstream IFC-USAID Fish Passage Workshop-2016, Nepal

17

Hopper (or Bucket) • Water retaining vessel that lifts the fish from the lower channel to the upper flume; the size of the hopper, a critical element, is based on design population

Holding Pool • Section of lower channel upstream of floor/wall diffusers and v-trap; fish are ‘caught’ in the pool and crowded above the hopper; size is based on design population IFC-USAID Fish Passage Workshop-2016, Nepal

18

IFC-USAID Fish Passage Workshop-2016, Nepal

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*hoppers are sometimes equipped with a brail extension for a gentler capture IFC-USAID Fish Passage Workshop-2016, Nepal

20

VELOCITIES IN CRUISING SPEED RANGE TO ALLOW FISH TO HOLD WITHOUT FATIGUE

VELOCITIES IN PROLOGNED RANGE AS DIFFUSERS CONTRIBUTE TO FLOW

LIFT TOWER

B E

4 ‐ 6 FT/S

C

1.5 ‐ 4 FT/S

1.0 FT/S

0.5 FT/S

F

A

D 1 ‐ 1.5 FT/S

1 ‐ 1.5 FT/S

H 1 ‐ 3 FT/S

BURST TO PASS ENTRANCE

G REAR DIFFUSER

HOPPER & PIT

HOLDING POOL & MECHANICAL CROWDER

AUXILIARY WATER SYSTEM (AWS)

IFC-USAID Fish Passage Workshop-2016, Nepal

FLOOR DIFFUSER

WALL DIFFUSER

ENTRANCE CHANNEL

ENTRANCE & GATE

lift velocities, U.S. Fish and Wildlife Service criteria

21

*at the top of the lift, hopper transfers fish into the exit flume; care must be taken to avoid injury here IFC-USAID Fish Passage Workshop-2016, Nepal

22

*return pipe â&#x20AC;&#x2DC;drainsâ&#x20AC;&#x2122; the upper flume; in doing so, it creates a gentle velocity which motivates fish to move IFC-USAID Fish Passage Workshop-2016, Nepal

23

IFC-USAID Fish Passage Workshop-2016, Nepal

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*as fish exit, they move past a counting window; static crowders on floor and wall move fish next to window IFC-USAID Fish Passage Workshop-2016, Nepal

25

*fish exit the system into the HW; trash racks (or grizzly racks) should be widely spaced and regularly cleaned IFC-USAID Fish Passage Workshop-2016, Nepal

26

IFC-USAID Fish Passage Workshop-2016, Nepal

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Capacity Considerations for Fish Lifts

# fish

t

peak day total run

â&#x20AC;˘ Unlike volitional ladders fish movement though lifts (and locks, T&T) is based on operator decisions; operating procedures affect capacity

Is lift cycled when operator chooses?

Is crowding Is lift cycled necessary? automatically?

Will lift operate when counting is affected by turbidity?

IFC-USAID Fish Passage Workshop-2016, Nepal

Is lift operated at night?

How was the operator trained?

28

Many Moving Parts!

IFC-USAID Fish Passage Workshop-2016, Nepal

29

Fish Lift Applications • Medium to high head dams • Costs are almost independent of height

• Advantages: • Suitable for shad and weaker swimmers struggle with fish ladders • Energetic costs are low compared to ladders of comparable height • May be easily integrated into a sorting facility

• Disadvantages: • Operational challenges • High maintenance cost due to many moving parts • Fish are ‘handled’ (potential source of injury) IFC-USAID Fish Passage Workshop-2016, Nepal

30

Questions?

31

IFC-USAID Fish Passage Workshop-2016, Nepal

Fishway Capacity peak day

n

D

# fish

peak day

n

T

t start

end

Brett Towler, Regional Fish Passage Engineer, USFWS IFC-USAID Fish Passage Workshop-2016, Nepal

1

Fishway Capacity… or Biological Capacity 1. Definitions and Concepts 2. Baffled Chutes 3. Lifts and Pool-type Ladders Will this fishway meets the population’s need?

IFC-USAID Fish Passage Workshop-2016, Nepal

2

Design Population, nT • Total annual count of fish designed to pass a barrier through the fishway. Self-sustaining population, restoration target, or other fisheries management goal typically used.

Peak Day, nD • Largest number of fish designed to pass during a 24-hour period.

Peak Hour, nH • Largest number of fish designed to pass in a 1-hour period during the peak day.

IFC-USAID Fish Passage Workshop-2016, Nepal

3

Idealized Uniform Fishway Loading migration season

# fish

peak day

n

D

n

n

D

T

t start IFC-USAID Fish Passage Workshop-2016, Nepal

end 4

Idealized Peak Fishway Loading peak day

n

D

# fish

peak day

n

T

t start IFC-USAID Fish Passage Workshop-2016, Nepal

end 5

Consequences of Inadequate Fishway Capacity crowding

n

D

delay # fish

2 A

B

capacity

1

3

C t

start IFC-USAID Fish Passage Workshop-2016, Nepal

end 6

Consequences of Inadequate Fishway Capacity crowding

n • Capacity is reached at delay point A; # 2 fish • Fish from 2 are either A B capacity crowded beyond design 1 3 limit of fishway OR delayed and crowded until point B; • From A to B, all fish, even in 1 , are crowded.

• Fish passing from point B to C are delayed only.

D

start

C t

end

Unsafe, Not timely, Not effective!

IFC-USAID Fish Passage Workshop-2016, Nepal

7

Biological Capacity of Baffled Chutes • Based on research by Slatick (1975), Slatick and Basham (1985), Haro et al. (1999), and monitoring studies, the Service has estimated capacities of Standard Denil ladders and Model A steeppasses.

USFWS R5 Criteria: STANDARD 4’ WIDE DENIL MODEL A STEEPPASS

25,000/yr adult American shad; or 12,000/yr adult Atlantic salmon; or 200,000/yr adult river herring 50,000/yr adult river herring; or 3,125/yr adult Atlantic salmon

IFC-USAID Fish Passage Workshop-2016, Nepal

8

est. capacity actual counts

IFC-USAID Fish Passage Workshop-2016, Nepal

9

Biological Capacity

of Pool-Type Ladders and Fish Lifts • Method based on alosine migration as the highest biological loading scenario • Techniques adapted from Clay (1995)* and refined by B. Rizzo (FWS-retired) and other Service engineers • Concept is different than a baffled chute; necessitates calculations that incorporate: 1. Crowding 2. Pass rate 3. Peak loading estimate * C. Clay (1995) “Design of Fishways and Other Fish Facilities” IFC-USAID Fish Passage Workshop-2016, Nepal

10

Calculating fishway capacity or “How to avoid traffic jams on the river” IFC-USAID Fish Passage Workshop-2016, Nepal

11

FISHWAY BIOLOGICAL CAPACITY CALCULATION Volume

Weight

Crowding

Pass Rate

Peak Hour

Peak Day

Population

1. Select or estimate a volume, V, of the component (ladder pool, lift holding pool, hopper) a) For a pool-type fishway this is the volume of water held in the pool under normal operating conditions. b) For a lift holding pool, this is the volume of water (used by fish) between the downstream edge of the hopper brail (or leading edge of the hopper) and the closed mechanical crowder. c) For a lift hopper, this is the water-retaining volume of the bucket.

A closed, V-trap crowder in its un-retracted position is 20 feet from the hopper in a 4-foot deep, 8-foot wide, lower flume; itâ&#x20AC;&#x2122;s volume is 640 ft3.

IFC-USAID Fish Passage Workshop-2016, Nepal 12

IFC-USAID Fish Passage Workshop-2016, Nepal

13

FISHWAY BIOLOGICAL CAPACITY CALCULATION Volume

Weight

Crowding

Pass Rate

Peak Hour

Peak Day

Population

2. Determine the weight of the target species, wf a) For the purpose of this calculation, select an appropriate “design weight”. b) An average weight of the species may represent stock in the river, but will underrepresent fishway capacity.

USFWS R5 Criteria:

adult wf

American shad Atlantic salmon blueback herring alewife

4.0 lbs 8.0 lbs 0.5 lbs 0.5 lbs

By convention, the Service often refers to multi-species fishway capacity in terms of an 4-pound “shad equivalent” 14

IFC-USAID Fish Passage Workshop-2016, Nepal

Non-Target Species Allowance, Cn • Multiplier applied to the volume required by fish in fishway design; accounts for: • Biological loading of non-target species • Off peak loading of other target species • Unusable volume in pools (e.g., sharp corners) • parameter is typically:

10% < Cn < 15% species 1 is peak load

# fish

species 2 off peak

IFC-USAID Fish Passage Workshop-2016, Nepal

• but should always be calibrated to local conditions!

species 1 species 2 species 3 species 4

t

15

FISHWAY BIOLOGICAL CAPACITY CALCULATION Volume

Weight

Crowding

Pass Rate

Peak Hour

Peak Day

Population

3. Assign crowding limit, vc, appropriate for fishway component (ladder pool, holding pool, hopper).

• • •

Ladder pools : vc=0.50 ft3/lbf Lift holding pools : vc=0.25 ft3/lbf Lift hopper : vc=0.10 ft3/lbf

USFWS R5 Criteria

Valid only for lift cycle times of 15 minutes or less.

IFC-USAID Fish Passage Workshop-2016, Nepal

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FISHWAY BIOLOGICAL CAPACITY CALCULATION Volume

Weight

Crowding

Pass Rate

Peak Hour

Peak Day

Population

4. Estimate the pass rate, r, for the fishway a) For pool-type ladders, the pass rate is the ascend rate, an estimate of fish transit time through the pools • Behavioral, not based on swimming speed • Assumes optimal conditions in ladder; (i.e., ladder not impacted by poor hydraulics, etc.) b) For lifts, the pass rate is the design cycle time • Design cycle time not fastest possible operation!

• Not fast-fishing mode • Cycle time includes fishing at peak hour, any mechanical crowding, and operation of any other normal lift component IFC-USAID Fish Passage Workshop-2016, Nepal

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Ascend Rate

Pass Rate of Pool-Type Ladders source

species

r, ascend rate (pools/min)

Bell (1991)

general

0.250 - 0.400

Clay (1995)

chinook salmon

0.200

Elling & Raymond (1956)

general

0.172 â&#x20AC;&#x201C; 0.303

Atlantic salmon

0.250

American shad

0.250

river herring

0.250

USFWS R5 Criteria IFC-USAID Fish Passage Workshop-2016, Nepal

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Cycle Time

Pass Rate of Fish Lifts • Cycle time set the pass rate • Prolonged time in the hopper induces stress in fish; should be avoided • For all but the tallest lifts, one can assume the lift can safely and effectively cycle within 15 minutes.

USFWS R5 Recommendation:

r = 1 cycle/15 min.

For lifts with longer cycle times, the crowding limit for hoppers should be increased beyond vc=0.10 ft3/lbf IFC-USAID Fish Passage Workshop-2016, Nepal

FISHWAY BIOLOGICAL CAPACITY CALCULATION Volume

Weight

Crowding

Pass Rate

Peak Hour

Peak Day

Population

5. Estimate the peak hourly loading, nH, on the fishway a) For existing facilities using historical count data b) For new facilities, the Service approach is to develop fish count regression analyses on similar facilities, in similar locations, that pass the same target species (or a reasonable surrogate fish) c) In the absence of better data, the follow relationship between peak day and peak hour may be used for screening-level estimates:

10% < (nH / nD) < 20% IFC-USAID Fish Passage Workshop-2016, Nepal

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FISHWAY BIOLOGICAL CAPACITY CALCULATION Volume

Weight

Crowding

Pass Rate

Peak Hour

Peak Day

Population

6. Estimate the peak daily loading, nD To facilitate design review, the Service develops regression analyses relating peak day to annual run American shad fish count relating peak day to seasonal count

â&#x20AC;¢

21

IFC-USAID Fish Passage Workshop-2016, Nepal

FISHWAY BIOLOGICAL CAPACITY CALCULATION Volume

Weight

Crowding

Pass Rate

Peak Hour

Peak Day

Population

7. Calculating fishway biological capacity for: • • •

Pool-type ladders Fish lift holding pools Fish lift hoppers

eq. (1)

eq. (2) IFC-USAID Fish Passage Workshop-2016, Nepal

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Capacity of an Ice Harbor Ladder Determine the capacity of a 5’ deep, 8’ by 10’ Ice Harbor ladder designed to pass American shad. Assume the impacts of coincident runs of other species contribute to a 15% non-target species allowance.

400

3

60 1

0.250 4

0.5

3

≅ 2,600 115%

Assuming the peak hourly loading is approximately 10% of the peak daily loading, and (based on regression analyses) the peak day typically passes 8% of the overall annual run.

1 2600 10% IFC-USAID Fish Passage Workshop-2016, Nepal

1 8%

325,000 23

Questions?

IFC-USAID Fish Passage Workshop-2016, Nepal

Downstream Fishways

Brett Towler, Regional Fish Passage Engineer, USFWS IFC-USAID Fish Passage Workshop-2016, Nepal

Downstream Bypasses 1.

2.

3.

4.

Purpose Attraction Flow “Uniform Acceleration Weir” Plunge Pools

IFC-USAID Fish Passage Workshop-2016, Nepal

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Fishways Technical

Nature‐Like

Upstream

Downstream

Chutes

Pool‐Type

Mechanical

(volitional)

(volitional)

(non‐volitional)

Bypass

Ramps

Step‐Pool

Roughened Channel

Behavioral

Turbines

Guidance Lift

Lock

Trap Physical/ Exclusion

Pool & Weir

Ice Harbor

Vertical Serpentine Slot Bypass

Steeppass

Denil

IFC-USAID Fish Passage Workshop-2016, Nepal

Transport

3

powerhouse

power canal wall

unit intakes create an approach velocity in the canal

IFC-USAID Fish Passage Workshop-2016, Nepal

4

guidance to bypass is minimal bypass provides an escape route for fish

unit intakes create an approach velocity in the canal

IFC-USAID Fish Passage Workshop-2016, Nepal

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guidance barrier

bypass

velocity components

approach velocity

IFC-USAID Fish Passage Workshop-2016, Nepal

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guidance barrier

bypass

sweeping velocity

approach velocity

IFC-USAID Fish Passage Workshop-2016, Nepal

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A. Physical and/or behavioral guidance device (e.g. louvers, angled bar racks) B. Bypass opening (e.g. weir, orifice, sluice gate, notch) C. Conveyance structure (e.g. open channel flume, conduit) D. Plunge pool

IFC-USAID Fish Passage Workshop-2016, Nepal

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IFC-USAID Fish Passage Workshop-2016, Nepal

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Bypasses • Provide an alternate route through the power station by “bypassing” the hazards of turbine entrainment • Project may have one or multiple bypasses working in conjunction with a guidance system • Bypass controls the amount of flow through the DS fishway (and influences attraction velocities) IFC-USAID Fish Passage Workshop-2016, Nepal

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Bypasses • Bypass may be pumps, siphons, pipe inlets, channels or weir (most common) • Bypasses are often installed in existing log sluices or flood gates • Can be permanent or seasonally installed • Guidance/bypass combination can be challenging at sites with unusual site layout

IFC-USAID Fish Passage Workshop-2016, Nepal

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Surface and Low Level Bypasses surface-oriented: • • • •

Atlantic salmon blueback herring Alewife American shad

benthic-oriented: • American eel • shortnose sturgeon

IFC-USAID Fish Passage Workshop-2016, Nepal

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surface bypass facilities 13

IFC-USAID Fish Passage Workshop-2016, Nepal

surface bypass facilities IFC-USAID Fish Passage Workshop-2016, Nepal

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multiple surface entrances IFC-USAID Fish Passage Workshop-2016, Nepal

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surface and low‐level entrances 16

IFC-USAID Fish Passage Workshop-2016, Nepal

Attraction to Downstream Fishways • As with upstream fishways, attraction has 3 important design elements: Where is the bypass?

How much discharge?

What is the strength of the “hydraulic signal” IFC-USAID Fish Passage Workshop-2016, Nepal

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Downstream Attraction Flow • Downstream bypass flow must be discernable in the presence of unit intakes (a competing flow) • Service criteria calls for DS bypasses to discharge:

minimum of 4% to 5% of station hydraulic capacity

USFWS R5 Criteria

(not to be confused with average daily generation!)

A new powerhouse with a hydraulic capacity of 7,800 cfs should maintain a DS bypass flow of 312 to 390 cfs IFC-USAID Fish Passage Workshop-2016, Nepal

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Downstream Attraction Flow • Bypasses weirs are the most common; flow is calculated by the well-known weir equation:

Q  CLH

3/ 2

• Discharge coefficient C varies (2 < C < 5) • function of weir shape, approach velocity, weir height and contractions

V C H IFC-USAID Fish Passage Workshop-2016, Nepal

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IFC-USAID Fish Passage Workshop-2016, Nepal

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Downstream Attraction Velocity • Velocity considerations beyond the current over the weir crest….

Bypass must generate velocities higher than the ambient flow to attract fish Flow over bypass must capture fish; …without eliciting a rejection response in fish IFC-USAID Fish Passage Workshop-2016, Nepal

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IFC-USAID Fish Passage Workshop-2016, Nepal

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flow over sharp crested weir 23

IFC-USAID Fish Passage Workshop-2016, Nepal

“Uniform Acceleration Weir” NU – Alden Weir

front IFC-USAID Fish Passage Workshop-2016, Nepal

side (cut‐away) 24

“Uniform Acceleration Weir” NU – Alden Weir

side (cut‐away) IFC-USAID Fish Passage Workshop-2016, Nepal

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IFC-USAID Fish Passage Workshop-2016, Nepal

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flow over NU-Alden weir 27

IFC-USAID Fish Passage Workshop-2016, Nepal

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IFC-USAID Fish Passage Workshop-2016, Nepal

“Uniform Acceleration Weir” NU – Alden Weir

IFC-USAID Fish Passage Workshop-2016, Nepal

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Transport or Conveyance Pipe IFC-USAID Fish Passage Workshop-2016, Nepal

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Plunge pool and receiving waters IFC-USAID Fish Passage Workshop-2016, Nepal

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transport pipe

fall height

receiving water

4D

pool

Horizontal Outlets

0

o

D

32

IFC-USAID Fish Passage Workshop-2016, Nepal

vx

equivalent fall height

4D

pool

D

inc. drop

vy=0

>0

vy

o

receiving water

Outlets w/Initial Vertical Velocity 33

IFC-USAID Fish Passage Workshop-2016, Nepal

Plunge Pools and Receiving Waters â&#x20AC;˘ Adequate depth in receiving waters to minimize injuries to fish exiting D/S bypass outlet â&#x20AC;˘ Plunge pool depth 4 feet USFWS or 25% of fall height R5 Criteria (whichever is larger)

IFC-USAID Fish Passage Workshop-2016, Nepal

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Questions?

35

IFC-USAID Fish Passage Workshop-2016, Nepal

Nature-Like Fishways

Brett Towler, Regional Fish Passage Engineer, USFWS

IFC-USAID Fish Passage Workshop-2016, Nepal

Nature-Like Fishways “An alternative to structures designed only to pass fish, is to design fishways that emulate natural rapids. Such designs are not only more likely to pass a wider range of species, but also provide rapids habitat similar to that lost due to dam construction.”

“Reconnecting Rivers” Aadland (2010) IFC-USAID Fish Passage Workshop-2016, Nepal

2

Fishways Technical

Nature‐Like

Upstream

Downstream

Chutes

Pool‐Type

Mechanical

(volitional)

(volitional)

(non‐volitional)

Bypass

Ramps

Step‐Pool

Roughened Channel

Behavioral

Turbines

Guidance Lift

Lock

Trap Physical/ Exclusion

Pool & Weir

Ice Harbor

Vertical Serpentine Slot Bypass

Steeppass

Denil

IFC-USAID Fish Passage Workshop-2016, Nepal

Transport 3

Nature-Like Fishway Layout and Hydraulic Design A Layout and Function

B Hydraulic Design

Bypass

Roughened Channel

Rock Ramp

Step‐Pool

Partial Rock Ramp

Hybrid

IFC-USAID Fish Passage Workshop-2016, Nepal

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Rock Ramp â&#x20AC;˘ Nature-like fishways that simulate conditions of natural rapids. Typically ramps run from the crest of the barrier (dam) down to grade and spanning the existing channel at a slope passable to fish.

IFC-USAID Fish Passage Workshop-2016, Nepal

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Partial Rock Ramp â&#x20AC;˘ Emulates natural rapids from the crest of the barrier (dam) down to grade, spanning only a fraction of the existing river channel

IFC-USAID Fish Passage Workshop-2016, Nepal

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Bypass â&#x20AC;˘ Consist of meanders a running laterally around a stream barrier. Bypasses are typically selected when passable slopes are not achievable in the existing river channel.

IFC-USAID Fish Passage Workshop-2016, Nepal

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Open channel (uniform) flow â&#x20AC;˘ Hydraulic control (and velocities) influenced by channel roughness or friction oBasis of baffled-chute designs

Roughened channel

Free overfall flow (i.e., weir flow) â&#x20AC;˘ Hydraulic control (and velocities) influenced by a transition from sub to supercritical flow o Basis of pool-type designs

Step-Pool Flow type is related to NLF hydraulic design!

IFC-USAID Fish Passage Workshop-2016, Nepal

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Traps and Pitfalls…

• Uncertainty inherent in roughness and discharge parameters in 1D hydraulics • Roughened channel • Manning’s n cannot be known a priori • Roughness must be estimated 2 1 1.486 3 • High variability Q AR S f 2

• Step‐pool structures

nn

• Discharge based on broad‐crested weir coefficients • Low variability

Q C CLH 3 / 2

IFC-USAID Fish Passage Workshop-2016, Nepal

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C

Over the range of weir heads and crest breadths used in NLF fishways, these coefficients vary from 2.60 to 2.68

• This variability in C results in only ~ 3% variability in discharge over the weir • In other words ‐‐ given accurate site data ‐‐ the designer can predict the relationship between discharge, velocity, and water surface elevation with reasonable accuracy.

IFC-USAID Fish Passage Workshop-2016, Nepal

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Depending on the degree of roughness designed into the channel, n may vary between 0.03 and 0.07

• For the range of typical slopes, depths, and cross‐ sections used in nature‐like fishways and constructed channels, a poorly chosen roughness value could result in > 100% error in discharge and velocity!

• Manning’s n cannot be calibrated or defined a priori. It must be estimated by the designer. Due to irregularity and diversity of nature‐like designs, n is very difficult to accurately predict.

• This is a potentially large source of error in establishing the discharge‐velocity‐stage relationship.

n

IFC-USAID Fish Passage Workshop-2016, Nepal

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IFC-USAID Fish Passage Workshop-2016, Nepal

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step‐pool structure IFC-USAID Fish Passage Workshop-2016, Nepal

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step‐pool structure IFC-USAID Fish Passage Workshop-2016, Nepal

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low‐flow notch

step‐pool structure IFC-USAID Fish Passage Workshop-2016, Nepal

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IFC-USAID Fish Passage Workshop-2016, Nepal

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IFC-USAID Fish Passage Workshop-2016, Nepal

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IFC-USAID Fish Passage Workshop-2016, Nepal

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elevations are critical and identified on design drawings IFC-USAID Fish Passage Workshop-2016, Nepal

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94

92 0 50 100 150

IFC-USAID Fish Passage Workshop-2016, Nepal 200 250 300

Cross Section 0+00

Cross Section 0+10

Cross Section 0+20

Cross Section 0+30

Cross Section 0+40

Cross Section 0+50

Cross Section 0+60

Cross Section 0+70

Cross Section 0+80

Cross Section 0+90

Cross Section 1+00

Cross Section 1+10

Cross Section 1+20

Cross Section 1+30

Cross Section 1+40

Cross Section 1+50

108

Cross Section 1+60

Cross Section 1+70

Elevation (ft) 110

Modeling is useful in identifying mean water elevations, but 1D has limitations Legend

WS 100-Year Flood WS 2-Year Flood WS May Mean

WS August Median

WS June Mean

106 WS 7Q10 Ground

104

102

100

98

96

Main Channel Distance (f t) 350

20

Nature‐like Fishways Bypass, step‐pool Example: Eel Weir Dam bypass, Oswegatchie River, Heuvelton, NY

Photo Source: J. Turek, NMFS IFC-USAID Fish Passage Workshop-2016, Nepal

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Nature‐like Fishways Bypass, step‐pool Example: Eel Weir Dam bypass, Oswegatchie River, Heuvelton, NY Step‐pool low‐flow channel

Water Management Structure Photo Source: J. Turek, NMFS IFC-USAID Fish Passage Workshop-2016, Nepal

Lower section, high‐flow channel 22

Nature‐like Fishways Bypass, step‐pool Example: Eel Weir Dam bypass, Oswegatchie River, Heuvelton, NY

Photo Source: L. Aadland

Low flows

High flows

IFC-USAID Fish Passage Workshop-2016, Nepal

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Nature‐like Fishways Bypass, roughened channel Example: Howland bypass, Piscataquis River, Howland, ME

Photo Source: Penobscot River Restoration Trust and Lighthawk IFC-USAID Fish Passage Workshop-2016, Nepal

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Nature‐like Fishways Bypass, roughened channel Example: Howland bypass, Piscataquis River, Howland, ME

•Channel bed material mix •Boulder placement •Inside channel bench •Resting pools

Photo Source: Penobscot River Restoration Trust IFC-USAID Fish Passage Workshop-2016, Nepal

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Nature‐like Fishways Bypass, roughened channel Example: Howland bypass, Piscataquis River, Howland, ME Flows: 09/28/15

10/22/15 Photo Source: B. Lake, NMFS

10/01/15

IFC-USAID Fish Passage Workshop-2016, Nepal

10/07/15 26

Nature-Like Fishways • Nature-like not natural!

• Constructed from rock and natural materials • High gradient, engineered channels

• Advantages • Aesthetics • Enhances passage for multiple species • Upstream and downstream passage

• Disadvantages • Size, cost, and lack of info on performance IFC-USAID Fish Passage Workshop-2016, Nepal

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IFC-USAID Fish Passage Workshop-2016, Nepal

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• Provides guidance on design of a step‐pool NLF • Bridges gap between concept and later design phases (i.e., HEC‐RAS modeling) • Includes free software

http://scholarworks.umass.edu/fishpassage_technical_reports/

IFC-USAID Fish Passage Workshop-2016, Nepal

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Recommendations 1. Requires comparable level of engineering to technical fishways 2. High-gradient hydraulically diverse structures • • • • •

Consider design flows Requires close scrutiny to assure water velocities allow passage Include fatigue analyses 2D or 3D CFD to evaluate design Calibration of CFD difficult; physical model or reference site may be necessary

IFC-USAID Fish Passage Workshop-2016, Nepal

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Recommendations (continued) 3. Bypasses and partial ramps may be susceptible to attraction failure • e.g., Bunt et al. (2010)

4. Recommended maximum slopes • 0-3% for roughened channel • 3-5% for step-pools

IFC-USAID Fish Passage Workshop-2016, Nepal

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Questions?

IFC-USAID Fish Passage Workshop-2016, Nepal

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