Simulation Softwares


Based on the protocol developed by EDF's  R&D, the Microhabitats Method Application Program is used to estimate the quantity and quality of physical fish habitats as a function of instream flow from structures such as dams and weirs.


The French legislation introduced to regulate the flows of water discharged downstream of hydropower plants (1) triggered the development of multiple research strands.
The scientific goal of this research work is to provide tools with which to assess the role played by these discharges on the natural habitats of living organisms. Based on the Instream Flow Incremental Methodology (IFIM) principle developed in the USA, the microhabitats method was designed and adapted to French watercourses in the 1990s by CEMAGREF (the research Institute now known as IRSTEA, the National Research Institute of Science and Technology for Environment and Agriculture) and the EDF's R&D department in conjunction with a number of other laboratories (Conseil Supérieur de la Pêche, ENSA Toulouse and the Universities of Toulouse and Provence).
This work resulted in two method application protocols. Both make it possible to track the trend in habitat quality scores for different fish species at different stages of development at a given location as a function of instream flow : Surface Pondérée Utile or SPU (Weighted Usable Area), which is a qualitative and quantitative measurement, and Valeur d'HAbitat or VHA (Habitat Value), which is solely a qualitative measurement.

(1) La Loi Pêche de 1984, puis la Loi sur l'Eau de 1992 et récemment la Loi sur l'Eau et les Milieux Aquatiques de 2006.


Two protocols have been developed to apply the microhabitats method to a section of river. They differ in terms of their approach to hydraulic effects.

  • the first – developed by Cemagref – creates a comprehensive hydraulic model of the section studied, which is particularly relevant for non-regulated rivers. The associated application program - EVHA (EValuation de l'HAbitat or the assessment of the physical habitat of fish within the river) – is available online from the Cemagref Lyon website
  • developed by EDF's  R&D, the second application protocol is based on simplified hydraulic modelling weighted by measurements taken at multiple instream flows, which is possible only for rivers in which flows can be regulated. The LAMMI program has been designed to implement the microhabitat method on the basis of this protocol
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