Options for re-establishing river continuity, with an emphasis on the special solution “fish lift”: examples from Austria.

<p>The European Water Framework Directive (WFD) became a major tool in European water policy. All the member states had to develop River Basin Management Plans (RBMPs). Austria’s first National Water Resource Management Plan was published in 2009 and describes measures to be set. Depending on the catchment size, ecological targets were defined on water body level, to be reached by 2015, 2021 or 2027. A priority goal is the re-establishment of river continuity. Therefore the Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management published a “Guideline for the construction of fish passes” in 2012.</p><p>We provide an overview on measures to re-establish river continuity that were recently planned or already established at the Inn catchment, a major tributary to the upper Danube River. Planning principles as well as details from the construction phase and monitoring concepts as well as first results are presented.</p><p>Founded in 1924 TIWAG started its business with the construction of the HPP Achensee, at the time one of Europe’s largest storage facilities. Since then TIWAG expanded its expertise on engineering, constructing and operating hydro power plants in Tyrol. In the first river basin management cycle at three hydropower plants, located in the“priority river network” (HPP Langkampfen, HPP Kirchbichl and HPP Imst - the latter with the weir Runserau and the water intake at Wenns), measures had to be developed to overcome discontinuity. During planning phase it was tried to apply “standard solutions” according to the Austrian guideline. This was possible for three sites, where we planned vertical slot fish passes in combination with natural bypass channels. To enable upstream migration at the weir Runserau, different alternatives were evaluated, but it was not possible to use a “standard solution”. A review about existing fish lifts was the basis for a promising solution. The chosen design combines a conventional fish migration facility (vertical slot) with a fish lift. Linked together those facilities are offering new, additional possibilities. The characteristics of this new concept and its advantages are presented.</p>

River continuity under difficult boundary conditions–useful steps and practical hints for designing a fish way

Most large and medium sized river basins in Germany have, over time, been affected by anthropogenic changes due to navigation, hydropower generation, and straightening and shortening of river courses for land reclamation. Consequently, there are many weirs inhibiting fish migration. The Ruhr River is affected by several such barriers or obstacles of which Baldeney Weir is the biggest. The search for an appropriate fish pass structure has not been easy given that the location is embedded in urban surroundings and used for traffic or recreation. This situation led to the establishment of an expert working group chaired by the Ruhrverband to discuss the problems and find a common solution. In a step by step approach, all necessary basic information was elaborated and evaluated, including consideration of diverse fish pass types. Setting up a working group of experts and responsible decision makers was found to be an appropriate method of overcoming differing opinions, sometimes based only on subjective, one-sided assessments, and reaching a mutually acceptable solution.