Oral Presentation International Conference on River Connectivity (Fish Passage 2018)

Fish passage at tidal barrier Nieuwe Statenzijl in The Netherlands, a regional perspective. (#189)

Peter Paul Schollema 1
  1. Regional Water Authority Hunze en Aa's, Veendam, GRONINGEN, Netherlands

Regional Water Authority Hunze en Aa’s is one of the 21 regional water management organisations in The Netherlands and is positioned in the NE corner of the country. The main responsibilities are water level management, flood defence and water quality management in the regional lakes, canals and river systems. As part of these water management tasks, RWA Hunze en Aa’s operates several sluices and pumping stations that discharge water from the regional rivers and polders into the estuary of the River Ems. These locations play an important role as access point to the hinterland for diadromous species like smelt, Atlantic eel, three spined stickleback, flounder and river lamprey. In the past these tidal discharge locations showed to be an almost impassable barrier for diadromous fish. Since 2001 several projects have been carried out to restore fish passage possibilities. A combination of a more “fish friendly” management of the sluices and the construction of technical fishways is used to allow diadromous fish to get passed these tidal barriers. The presentation will focus on the practical discussions (salinity, sediment, safety) and monitoring results for one of the main tidal discharge sluices at Nieuwe Statenzijl in the River Westerwoldsche Aa. This location has been fitted with a combination of adapted management of the sluice doors, an eel pass and additional “cat flaps” allowing millions of diadromous fish to pass.