The purpose of this project was to identify the most adequate methods for eflows estimation in Poland. These considerations took into account the specifics of environmental conditions, the availability and reliability of the data as well as the requirements of the Water Framework Directive and the European Commission regarding eflows. The literature review is followed by development of an overall concept and a test pilot investigation, during which the assumptions have been tested. For the pilot project phase we proposed utilization of two types of methodologies:

• Hydrological methodology (desktop) - for morphologically unaltered  water bodies;

• Habitats simulation methodology  - for modified, heavily modified and artificial water bodies.

The limitation of hydrologic desktop methods is to identify flow thresholds reflecting the variability of habitat conditions. Hence the thresholds are determined with help of MesoHABSIM model developed for 6 Target Fish Guilds Communities typical for Polish rivers and habitat time series analysis. The result are river type specific seasonal value of subsistence, base, high pulse, and overbank flows, together with their frequencies and durations.