Selection of mitigation measures interface for the reisk assessment of fish mortality during downstream fish passage in the FIThydro Decision Support System
The FIThydro Decision Support System (DSS), developed by the University of Hull and the Technical University of Munich is now online accessible for users. The DSS supports informed decision making on the design and operation of new and refurbished hydropower plants. It helps users to screen potential mitigation measures that could be appropriate for their specific hydropower schemes.

The proliferation of hydropower development to meet obligations under the Renewable Energy Directive has seen the emergence of a conflict between the hydropower developers and the fisheries and conservation sectors. On the one hand, the hydropower sector is promoted as an important renewable source of green energy and developers want clear guidance on environmental requirements. On the other hand, fisheries and conservation interests are concerned with the impacts of these schemes on the riverine environments and want to be consulted on the proposed schemes. Therefore, a joined-up response to planned developments with sound guidance and decision-making is important to both the hydropower industry and the fisheries and conservation sectors.

Existing guidelines are often limited in their assessment and appropriate mitigation of risks, and uncertainty about the site-specific impact of schemes on fisheries and the environment limits the application of such generic guidance to individual HPPs. Few guidelines provide support for the decision making process at each stage of the evaluation. The FIThydro Decision Support System addresses this need for a robust and transparent, evidence-based, tool to support for decision making that is easy to use while also enabling a high level of appropriate environmental protection and mitigation.

The planning and decision framework of the DSS is designed to be sufficiently flexible to address decision making in two similar but contrasting scenarios (use cases):

  1. Impact assessment and planning of new mitigation measures for existing HPPs;

  2. Planning and risk assessment of a new HPP scheme proposal.

Four steps in the decision framework

The DSS web-tool is based on the project management approach and outlines the steps that should be undertaken for the initial screening of a project to appraise the impacts, risks and scope options for further diagnosis and mitigation

The process leads the decision maker through four key steps which act to characterize, risk-assess (and prioritize) the scheme(s) together with the identification of the most appropriate and potentially cost-effective mitigation options addressing the hazards and impacts arising due to the nature and context of the specific scheme(s).

The four key planning steps are as follows:

Step 1 Pre-screening characterization, hazard identification & risk assessment

Step 2 Ecological status assessment and review of existing mitigation

Step 3 Identification of appropriate mitigation measures and synergistic solutions

Step 4 Risk-based decision of scheme plan OR Scoping of detailed cost-efficient mitigation plan

The decision process leads ultimately to a structured assessment of the acceptability of a proposed scheme or scoping the measures required for mitigating existing hydropower plants, with associated risks and uncertainty.

The 4 steps of the Decision Support System (DSS) framework for risk assessment and mitigation planning for existing hydropower schemes and new proposals

Web tool implementation

The DSS is presented in the form of an open access web-based tool, which utilizes and showcases some of the tools and outputs produced by the FIThydro project. It is freely accessible online at

Upon accessing the DSS, question catalogues, risk assessments and filtering tools are produced which cover aspects of ‘initial screening’, ‘ecological impacts’, ‘environmental status’, ‘mitigation measures’, and ‘risk and uncertainty’. Taken together, these aid the production of a project screening/scoping report designed to provide a systematic approach to decision-making for proposals relating to hydropower schemes and their mitigation.

Through this, the DSS enables operators and regulators to develop structured proposals for new HPP schemes, and to both, review and risk assess, those proposals whilst identifying appropriate mitigation measures to address the impact of both new and existing HPP schemes.

Richard Noble, UHULL