hydropeaking and minimum flow the french approach p baran
Download
Skip this Video
Download Presentation
Hydropeaking and minimum flow : the French approach. P. Baran

Loading in 2 Seconds...

play fullscreen
1 / 35

Hydropeaking and minimum flow : the French approach. P. Baran - PowerPoint PPT Presentation


  • 147 Views
  • Uploaded on

CIS ECOSTAT - HYDROMORPHOLGY WORKSHOP 12th and 13th June 2012 - Brussels. Hydropeaking and minimum flow : the French approach. P. Baran. Pôle Ecohydraulique. French context of water storage. Total amount of water per year in stream : 200 billion m3

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Hydropeaking and minimum flow : the French approach. P. Baran' - barto


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
french context of water storage
French context of water storage
  • Total amount of water per year in stream : 200 billion m3
  • In 2009, 33,4 billion m3 in total collected :
    • 64% for the production of electricity
    • 17% for drinking water
    • 10% for the industry
    •  9% for irrigation
  • The water storage has been developed for :
    • irrigation,
    • hydropower generation
    • drinking water
  • 126 000 samples of water whose 80,000 for agricultural use
french context for hydroelectricity
French context for hydroelectricity
  • Production :
    • Between 60 to 70 TWh for hydroelectricity (550 TWh of total production),
    • 50% of the production by hydropower plants managed by hydropeak with to type of schemes :
      • organized in line (eg: Durance, Dordogne, Truyère).
      • organized with high-head storage (Alpine and Pyrenean mountains)
french approach
French approach
  • Identification and quantification of changes of flow regime with two priorities :
    • Low flow
    • Hydropeaking
  • Mitigation measures to increase low flow value (large scale (2014)) and/or to change locally the hydropeaking management.
focus on hydropeaking

Principales centrales hydrauliques

Focus on hydropeaking
  • More than 150 hydroelectric schemes managed by hydropeaking in France.
  • ≈ 3000 kms of streams concerned by hydropeaking.
slide7

The French approach

  • 1. Identifications of flow modifications induced by hydropeaking

Analysis of flow regime

7

slide8

The French approach

  • 2. Identifications of habitat alterations related to the flow modifications induced by hydropeaking

Characterization of fish habitats by hydraulic models and habitat preference curves of species and life-stages

8

slide9

The French approach

  • 3. Proposal of mitigation measures and assessment

Approach based on hydraulic models and habitat mapping

9

method to characterize the hydrological disturbance
Method to characterize the hydrological disturbance
  • Data base : gauging stations
  • Hourly flow analysis
    • Identification of each flow variations
    • Differentiation between the hydropeak and natural variations
method to characterize the hydrological disturbance1
Method to characterize the hydrological disturbance
  • number of hydropeaks,
  • Each hydropeak is characterized by :
    • base flow,
    • maximum flow,
    • range,
    • rate of change,
method to characterize the hydrological disturbance2
Method to characterize the hydrological disturbance
  • For each year :
    • Number of hydropeaks
    • Statistical characteristics of :
      • base flow,
      • maximum flow,
      • range,
      • rate of change,

Number of hydropeaks

Rate of change

Base flow

Range

slide14

Daily hydropeaks

Hourly hydropeaks

Weekly hydropeaks

characterization of hydrologic perturbation
Characterization of hydrologic perturbation:
  • Construction underway of an indicator of hydrologic perturbation due to hydropeaking events.
  • Based on discriminant analysis :
  • base flow,
  • maximum flow,
  • range,
  • rate of change,
  • number of hydropeaks
characterization of hydrologic perturbation1

Saint-Béat - 2006

Characterization of hydrologic perturbation:
  • The index just evaluate the hydrological perturbations and not ecological effects
  • The index allow to analyse the evolution of the perturbation along a stream or between years.

Chaum - 2006

Upstream

Valentine - 2006

Downstream

global situation in france
Global situation in France:
  • 80 stations were analysed in 50 french streams. 58% of stations with strong alterations of flow regime
impacts on fish habitat
Two types of impacts on fish habitat depending on morphology of stream.Impacts on fish habitat

Mountain steep stream : hydraulic conditions during high flow

impacts on fish habitat1
Effects of hydropeaking management during life-stages of fishImpacts on fish habitat

Lez river (MD : 1 m3/s)

Hydrologic perturbation very marked, maximum discharge 4 m3/s (≈4 times MD), between 150 and 300 hydropeaks per year.

impacts on fish habitat2
Two types of impacts on fish habitat depending on morphology of stream.Impacts on fish habitat

Braided streams :

Hourly variations on wetted perimeter dewatering fish habitats on shallow shoreline areas and trapping fry in disconnected secondary channels

impacts on fish habitat3
Impacts on fish habitat
  • Monitoring two streams (MD :107 m3/s; MD : 20 m3/s)

Line of lakes and hydropower plants

Hydrologic perturbation very marked, maximum discharge 35 m3/s (≈1,8 times MD), between 150 and 300 hydropeaks per year.

Hydrologic perturbation marked or very marked, maximum discharge 340 m3/s (≈3.2 times MD), between 100 and 240 hydropeaks per year.

impacts on fish habitat4
Impacts on fish habitat
  • Monitoring ecological effecfs of hydropeaks
    • Dewatering of salmonid redds and mortality of eggs (30% of the total redds).
    • Trapping of fry in disconnected secondary channels and mortality (6000 fry/year on 6 kms of stream).

Back to base flow

During a hydropeak

mitigation measures
Mitigation measures
  • Two types :
    • Changes on hydropeaking management :
        • Number of hydropeaks during specific biological periods,
        • Base flow, range, maximum flow, rate of change
    • Changes on stream morphology :
        • Connectivity of secondary channels,
        • River banks
        • Topography of gravel bar
mitigation measures1
Mitigation measures
  • Base flow increased :
    • from 0.5 m3/s to and 4 m3/s (5-20% of MD) in winter and spring, 1 m3/s the rest of the year
    • From 10 m3/s to 30 m3/s (28% of MD) in winter and spring (15/11-15/06), 10 m3/s the rest of the year.
  • Maximum discharge limited :
    • to 35 m3/s (less than 2 times MD), if possible, in spring (15/03-15/06).
    • to 190 m3/s (less than 2 times MD), if possible, in spring (15/03-15/06).
  • Discharge downramping rate of change limited :
    • to 20 m3/s/h in spring (15/03-15/06).
    • to 30 m3/s/h all year round.
  • Work on morphology to ensure permanent supply of secondary channels.
mitigation measures2
Mitigation measures
  • Efficiency:
    • Only ≈ 5% salmonid redds dewatered, instead of 30% without base flow increase.
    • Significant decrease of fry mortality in connected secondary channels.
effects on electricity production
Effects on electricity production
  • There were compensations for the losses of electricity production. In general, losses of production varied between 0,5 % to 2% of the total potential of peak production.
  • They remained quite limited because of the line organization. Only the production of the last hydropower plant is really affected.
  • All decisions of flow changes were made ​​in consultation with the electricity company
evolution of low flow
Evolution of low flow
  • Analysis of the evolution of low flow at large scale during the 3 last decades (Guintoli and Renard, 2010).
    • Volume
    • Duration
    • Time (begining and end)
evolution of low flow1
Evolution of low flow
  • Significant evolution of low flow conditions.
fish communities and low flow
Fish communities and low flow

Changes in fish communities in relation to low flow conditions

french approach1
French approach
  • The French Water Law impose minimum values of flow :
    • 5% to 10% of mean annual flow in 2014 for all dams and weirs
  • Locally, for each dams or weirs, the value of minimum flow can be increased based on study using microhabitat methodology.
conclusions
Conclusions
  • Modifications of flow regime are very important in France for a large part of water bodies.
  • A focus was made on hydroelectricity use with :
    • an evaluation at large scale for hydropeaking effects on flow regime,
    • the definition of mitigation measures at small scale
  • No direct relationships were established with biological index related to ecological status assessment of water bodies.
ad