The main emphasis of this paper is on the negative effects of sedimentation on the most highly endangered fish of Europe Romanichthys valsanicola and the habitats of its main trophic resource Rhithrogena semicolorata. Some inexpensive and easy-to-implement solutions are identified and proposed (dam reservoir related recommendations for basin sediments management, forestry related recommendations for sediment basin management, basin sediments general management recommendations, riverbed ecological reconstruction approach proposal, etc.) in the paper with the same conservative purpose for Romanichthys valsanicola species in the actual situation of habitat loss and drastic regress of this globaly-unique fish population.

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proposes a technical solution to facilitate fish migration upstream the weir located on Crişul Repede River, near the Ferdinand Bridge from the Oradea Town. The proposed solution provides building of a system to facilitate fish migration, placed on the left bank of Crişul Repede, meant to restore the longitudinal connectivity of Crişul Repede River in front of the Ferdinand Bridge weir and to facilitate the access of the migratory fish species to upstream breeding habitats. The proposed migration system are based on the gravitational fall of water and will lead to the restoration of the longitudinal connection of the Crişul Repede River near the weir selected as case study, and will reconnect a habitat with a length of approximately 4 km, that will contribute to insuring of optimal conditions for developing migratory fish species present in the area

Longitudinal connectivity restoration of watercourses is a major duty for scientists (biologists, hydro engineers, chemists etc.) that, by the means of technical exchange via conferences, projects, workshops, universities, and institutions demonstrate the major importance of a natural (non-anthropic) function of the lotic ecosystems. On the Ialomiţa River, the discharge sills located downstream from Padina chalet block the migration of some fish species, such as the brown trout (Salmo trutta) and the bullhead (Cottus gobio), prohibiting access to foraging areas and springs. Water Framework Directive 60/2000 / EC provides a legal framework for restoring "good status" of longitudinal and lateral connectivity of watercourses. Our proposed solution I can be applied to other discharge sills and dams sized between 3m and 6m high, and, where feasible can utilize existing power sources of some discharge sills. Solution II's concepts allow the dimples inside the concrete plate to serve as a rest and recovery area for migratory species. Such benefits that ensure upstream/downstream fish migration while allowing discharge management to continue is unattainable in conventional systems. After solution II is applied the discharge sill does not lose any baseline characteristics while maintaining the original hydro-technical design objective, flood dissipation.

The paper presents a case study that proposes a technical solution to facilitate fish migration upstream the discharge sills located on Someşul Mic River, near the Mănăştur Dam from the Cluj Napoca Town. The proposed solution provides building of a system to facilitate fish migration, placed on the left bank of Someşul Mic River, meant to restore the longitudinal connectivity of Someşul Mic River in front of the Mănăştur Dam discharge sills and to facilitate the access of the migratory fish species to upstream breeding habitats. The proposed migration system is based on using traction of winches and the gravitational fall of water and will lead to the restoration of the longitudinal connection of the Someşul Mic River near the weir selected as case study, and will reconnect a habitat with a length of around one km, that will contribute to insuring of optimal conditions for developing migratory fish species present in the area.