International Fish Screening Conference Southampton 29-30 March 2011

Downstream bypass facilities for salmon and eel at small hydro power plants in France

F. Travade M. LarinierEDF R&D ONEMA

6, quai Watier Institut de Mécanique des Fluides 78400 CHATOU Avenue du Professeur Camille Soula

31400 - TOULOUSEfrancois.travade@edf.fr larinier@imft.fr

CONTENT

1. French context

2. Evaluation of mortalities due to hydropower

3. Devices for juvenile salmon- experimental techniques- surface bypasses- behavioral devices

4. Experiments on adult eel

5. R&D French program on eel and obstruction

FRENCH CONTEXT

Regulation (1984)Some rivers are classified as « migratory fish rivers »11 « official » migratory fish species : salmon, sea trout, shad (2), lamprey (2), eel, sturgeon, brown trout, greyling, pikeObligation to insure upstream and downstream fish passage at dams on migratory fish river

Hydropower characteristicsAbout 2000 hydropower dams in FranceMainly small plants on migratory fish rivers : H<5m ; Q < 50 m3/sTurbine mortality mainly moderate for salmon juveniles : 5 -10 %Turbine mortality higher for adult eel : 15 – 50 %

Experimental studies about downstream migration devices in 80 ‘- 90’for salmon and since 2000 for eel

CONTENT

1. French context

2. Evaluation of mortalities due to hydropower

3. Devices for juvenile salmon- experimental techniques- surface bypasses- behavioral devices

4. Experiments on adult eel

5. R&D French program on eel and obstruction

PASSAGE THROUGH SPILLWAYS and TURBINES

Passage through spillways is generallynot a problem in France, due to the lowhead of installations: spillways are the safest way for fish to migrate downstream

Passage through turbines juvenile salmonids (15-20 cm)

Pelton turbines: very high mortality rate Francis Turbines : range of mortality rate 5-90%, usually: 15-40%Kaplan turbines : range of mortality rate 2-20%, usually: 5-12%. Mainly used on migratory fishrivers in France

adult eel: mortality rate 4-5 times higherthan that for juvenile salmonids

CONTENT

1. French context

2. Evaluation of mortalities due to hydropower

3. Devices for juvenile salmon- experimental techniques- surface bypasses- behavioral devices

4. Experiments on adult eel

5. R&D French program on eel and obstruction

DOWNSTREAM MIGRATION DEVICES FOR SALMON SMOLTS

Because they are a large number of existing hydro plants in France itappeared difficult to install physical screens to prevent smolt passage through the turbines without resizing the intakes

So, in the Eighties and Nineties experiments were conducted to :

Quantify mortality among smolts passing through turbines to assessthe impact of each hydropower plant

Design and test surface bypasses combined to conventionaltrashracks

Test behavioral devices

Field experimental techniques to test dowstream devices

Radio tracking

Mark-recapture

PIT tagging

CONTENT

1. French context

2. Evaluation of mortalities due to hydropower

3. Devices for juvenile salmon- experimental techniques- surface bypasses- behavioral devices

4. Experiments on adult eel

5. R&D French program on eel and obstruction

Downstream bypass for smolts : operating principle and parameters

St Cricq (Gave d ’Ossau)Trashrack : behavioral repelling effect

Surface Bypass

Bar spacing < 3-4 cmWater velocity < 40-50 cm/s

Location close to the trashrack

Discharge 2%-10% Turb. Dis

Hydraulic patterns near the bypass: no turbulences

no upwellings

Dam River

Max turbine

discharge ( m3/s)

trashrack bar spacing

(mm)

Bypass inflow (

m3/s)

Bypass inflow / turbine

discharge (%)

Number of entrances

Entrance width (m)

Evaluation method *

Efficiency (%)

Evaluation date

Soeix Gave d'Aspe 35 35

1.2 (last tests) 2 (now)

8 1 1.8 MR + Rad 55-68 1992-1995

Bedous Gave d'Aspe 28 30 0,7 2.8-4 1 0.7 MR

+MD+Rad38-74

(mean 55) 1995-1998

Camon Garonne 85 40 3 4-8 1 3 MR + Rad 58-85 (mean 73) 1996-1998

St Cricq Gave d'Ossau 19 25 mean 0.65 mean 3.4 2 0.8 MR + Rad 63-100

(mean 79) 1996

Baigts Gave de Pau 90 30 2,2 2-6 1 2 Rad 92,5 2001

Castetarbe Gave de Pau 36 25 1.2-2.4 3-6 3 1 Rad 100 2001

Guilhot Ariège 27 32 1.33-1.75, mean 1.55 6-8 1 1.1 MD 75 1997

Las Rives Ariège 39 40 1.24-1.80, mean 1.55 3-4.8 1 1.9 MD 49 1997

Crampagna Ariège 24 30 1.05-1.55, mean 1.31 ? 1 1.4 MD 66 1998

Las Mijanes Ariège 40 30 mean 0.8 1.9-3.3 1 2.25 MD 32 1999

Halsou Nive 30 30 0.4-0.8 1.3-2.6 1 0.9 MR + Rad mean 56 1995-1999

Poutès Allier 28 30 2 7.1 1 2.5 Rad 90 2004

Characteristics and efficiency for salmonids of some bypasses tested in France

24-90 m3/s25-40 mm 1.3-8 % 32-100%

Location and discharge effect (Soeix HPP - Gave d’Aspe river)

15 m

3.5 m

TD : 35 m3/s

BPD : 0.6 m3/s6m upstream trashrack

BPD : 0.8 m3/s1.5 m upstream trashrack

BPD : 1.8 m3/s1.5 m upstream trashrackupwelling removal by deflector

Bypass efficiency

Bar spacing and BP discharge effect (Baigts Gave de Pau riverBypass

Low efficiency due to large bar spacing (7 cm) and insufficient discharge in the bypass (0.6 m3/s)

Good efficiencyAfter changingThe trashrack (3 cm)And increasing theBypass discharge(2.2 m3/s)

Bypass efficiency

90 m3/s40 m

Low efficiency due toan upwelling near the bypass entrance

High efficiency achievedby removing the upwelling with a submergeddeflector plate

Hydraulic patterns effect (Camon - Garonne river)

Bypass included in theTrashrackTD : 85 m3/sBD : 2 – 3 m3/s

Bypass efficiency

LOCATION OF DOWSTREAM BYPASSES AT

HYDROELECTRIC PLANT INTAKES

EXAMPLES AND EFFICIENCY OF SURFACE BYPASSES

HALSOU (Nive)

CASTETARBE (Gave de Pau)

POUTES (Allier)

Efficiency: from 10% to >80%generally very limited with 5-6 cm spacing (10-20%), 60-70%: with 3-4 cm spacing and good hydraulic conditions80-90%: with 2.5 cm spacing and good hydraulic conditions

LAILHACAR (Gave d’Ossau)

CONTENT

1. French context

2. Evaluation of mortalities due to hydropower

3. Devices for juvenile salmon- experimental techniques- surface bypasses- behavioral devices

4. Experiments on adult eel

5. R&D French program on eel and obstruction

BEHAVIORAL DEVICES

Principle : using stimuli to guide, repell or attrackfishElectric guiding screen

15% efficiency (8-28%) to guide smolts to a bypass with a 20 m long screen (Halsou)

Acoustic screen0% efficiency to guide smolts to a bypass witha BAFF (FGS) : acoustic field combined to an air bubble curtain (Halsou)0% efficiency to repell smolts from an intakecanal entrance by an acoustic screen (FGS) (St Cricq)

Night lighting deviceLow wattage mercury vapor light (50-80 W) atthe bypasses entrance increases theirefficiency. Very efficient on low velocityintakes (Intakes on lakes / Ex Poutès)

CONCLUSIONS for salmonids

Surface bypass combined with trashracks can be a simple solution to solve downstream migration problems for small scale power plants where 60 - 80 % efficiency is sufficient

Some criteria must be respected and several parameters carefully examined before designing a bypass :

Bar-spacing at trashracks < 30 - 40 mmWater velocity < 0.4 – 0.6 m/sFlow pattern conditions to determine the location of the bypassNo upwelling near the entranceBypass discharge / turbine discharge = 2 - 10 %

Efficiency can vary strongly in the time if some parameters are modified (ex : flow patterns and velocity with variation in plant operation Pb in France)

Behavioral devices (electric, acoustic screns) tested in France have a low efficiency for guiding salmonids to a bypass. Night lighting the surface bypasses entrance by low wattage mercury vapor light can improve the bypass efficiency

CONTENT

1. French context

2. Evaluation of mortalities due to hydropower

3. Devices for juvenile salmon- experimental techniques- surface bypasses- behavioral devices

4. Experiments on adult eel

5. R&D French program on eel and obstruction

EXPERIMENTS ABOUT DOWNSTREAM MIGRATION DEVICES FOR SILVER EEL

Fields experiments conducted to Analyse the eel behaviour near the HPP intakesimprove the efficiency of surface and bottom bypasses similar to those used for salmonids

Experimental studies radiotracking and transponders (PIT tags)

Powerhouse

Spill Gate 2 Spill Gate 1FlapGate

Gave de Pau

Old Fish Pass

Small ScalePowerhouse

Intake Trashracks

Fish Lift

Downstream FishBypasses Entrances

Tailrace

Forebay

Intake

Powerhouse

Spill Gate 2 Spill Gate 1FlapGate

Gave de Pau

Old Fish Pass

Small ScalePowerhouse

Intake Trashracks

Fish Lift

Downstream FishBypasses Entrances

Tailrace

Forebay

Intake

RE

VA

AG

ST

CLTU EX

ABCD

E

MGMT

RE

VA

AG

ST

CLTU EX

ABCD

E

MGMT

HALSOU EXPERIMENTS : 1998 - 2000

Surface bypass1.4 m width / 0.6 m3/s2% TD

Bottom bypass1.3 w x 0.5 h0.6 m3/s2% TD

Surface gate

DischargeTower

18 m

3.5 m

HALSOU EXPERIMENTS : 1998 - 2000

30-40%

8-15%

40-50%

Combined efficiency of the two bypasses = 56 – 64 % (mean value for the 3 years)

Bottom Bypass 3 to 4 times more efficient than Surface Bypass

Bottom Bypass48%

Spillwaw10%

Turbines32%

Fishway0%

Surface Bypass10%

38 radiotracked eels

Power plantGate1Gate2

Surf. Bypass

Fishway

Surf.gate

Trashrack

Forebay

Power plantGate1Gate2

Surf. Bypass

Fishway

Surf.gate

Power plantGate1Gate2

Surf. Bypass

Fishway

Surf.gate

Trashrack

Forebay

Qturb = 90 m3/s

BAIGTS Experiments Surface bypass 2004 and deep bypass 2005

width 1.8 m2.2 m3/s2.5% TD

DAM

POWER PLANT

40 m

5.5 mSpacing 3 cm

Surface bypass: test 2004

Deep bypass : test 2005

Deep entrance : - 7m

Efficiency for smolts 90%

velocity < 0.4 m/s

Qturb = 90 m3/s

BAIGTS 2006Surface bypass and physical screen

DAMPOWER PLANT

Surface bypass

Bar spacing : 3 cm

Physical screen simulated by using eels with body larger than the bar spacing for the experiment

60%

18%

15%

8%

2004 : surface BypassSmall eels

54%

3%

44%

0%

2005 : deep BypassSmall eels

8%

24%

68%

0%

2006 : surface Bypasslarge eels

Bypass Efficiency

Surface bypass less efficient for eel than for salmonDeep bypass less efficient than surface one.

Opposite to Halsou Position ? Size of the plant ?Trashrack has a poor repelling effect compared to

smoltsSmall bar spacing trashrack (physical screen) and

small velocities = delay 1 to 14 days before passing by bypass or flood gates

Spillways, the best bypass ?

2006

0

50

100

150

200

250

300

01/1

1/06

06/1

1/06

11/1

1/06

16/1

1/06

21/1

1/06

26/1

1/06

01/1

2/06

06/1

2/06

11/1

2/06

16/1

2/06

21/1

2/06

26/1

2/06

31/1

2/06

05/0

1/07

10/0

1/07

15/0

1/07

20/0

1/07

25/0

1/07

30/0

1/07

04/0

2/07

09/0

2/07

14/0

2/07

19/0

2/07

24/0

2/07

01/0

3/07

06/0

3/07

11/0

3/07

16/0

3/07

21/0

3/07

26/0

3/07

31/0

3/07

05/0

4/07

10/0

4/07

15/0

4/07

Date

Riv

er F

low

(m3 .s

-1)

Spillway Turbine Bypass River Flow

Passage at the plant occured mainlyduring peak flow discharges of the river

High escapement by the spillways occursfor high ratio of spill flow discharge to total river flow discharge

Spillways, the best bypass ? Modelling the escapement

Escapement probabilities at the Baigts plant is a function of :

Ratio Qspill / QriverEel length

The effect of eel length is due to the possibilities of passage through the trashrack (3 cm bar spacing)

CONCLUSIONS FOR EELSurface bypass and bottom bypass combined with trashracks are less efficient for silver eel than for smolts mainly because the behavioural repellent effect of the trashrack seems to be low for eelBypasses combined with a 3 cm bar-spacing may be partially efficient for very small plants with a favourable configuration : 50-60 % at HalsouOn larger plants or on less favourable configurations, this efficiency appears to be very low. One solution could be the use of a smaller bar spacing (< = 2cm) to create a physical barrierThe bar spacing has to be determined as a function of the eel size in the local population The use of a physical barrier needs low velocities (<= 40-50 cm/s ?) in front of the trashrackto prevent fish impingement and so, a risk of mortality higher than turbine passage A physical barrier causes delay to find bypasses or to wait for flood gates opening. It could be problematic in case of multiple plants The feasibility of the installation of small spacing trashrack can be problematic for the operation of existing hydro plant but can be possible for the future (small ?) plantsEscapement by spillways could be important on some plants according to the eel length, the ratio turbine discharge / river discharge and according to the migration rhythms. This escapement has to be evaluated case by case Alternative solutions :

behavioural devices (light, sound…?) altered generation schedule (turbine shutdown) during the migration peaksFish friendly turbinesTrap and transport

CONTENT

1. French context

2. Evaluation of mortalities due to hydropower

3. Devices for juvenile salmon- experimental techniques- surface bypasses- behavioral devices

4. Experiments on adult eel

5. R&D French program on eel and obstruction

French R&D program on eel and dams Under progress / Results end of 2011 (1)

1 - Prediction of turbine mortality : statistical analysis of experimental mortality tests (70 experiments around the world)

2 – Modeling the cumulative mortality due to turbine passage on a river with several hydro plants

3 – Migrating behaviour and passage ways of silver eel along a small river (Gave de Pau river) with several hydro plants

4 - Migrating behaviour and passage ways of silver eel along a large river (Rhine river) with several hydro plants

5 – Test of eel mortality by passing in large turbine : tests on 3 turbines with the HI – Z tags technique (Rhine and Rhône rivers)

Taux

de

mor

talit

é (%

)

Vitesse de rotation (trs/min)

[0-100[ [100-200[ [200-300[ [300-400[0

102030405060708090

100

% b

arra

ge

% b

arra

ge

0 0.2 0.4 0.6 0.8 10

0.2

0.4

0.6

0.8

1

Qdev/Qriv

French research program on eel and dams Under progress / First results end of 2011 (2)

6 - Prediction of eel downstream migration peaks by using environmental parameters (river Loire eel fishery)

7 – Prediction of eel downstream migration peaks by using the bio monitor MIGROMAT® on the river Shannon

8 – Measurement of eel downstream migration by using a sampling fishery (river Dordogne)

9 – Test of an infra sound deterrent device (ProFish) at the intake of two hydro plants (Gave de Pau river)

10 – Design of Fish Friendly intakes for HPP

période effective de pêche CPUE observées CPUE prédites

0

1

2

3

4

5

6

7

8

1/10 15/10 29/10 12/11 26/11 10/12 24/12 7/1 21/1 4/201

2

345

6

78

9

10

0

1

2

3

4

5

6

7

8

1/10 15/10 29/10 12/11 26/11 10/12 24/12 7/1 21/1 4/201

2

345

6

78

9

10

()

année test 1997

préd. vérifiée = 100%

French research program on eel and dams Under progress / First results end of 2011 (3)

11 – Improvement and test of a the VLH Fish Friendly turbine

12 – Financement for the development of the Alden Fish Friendly Turbine (USA)

Thank you for your attention