Benefits and consequences of managing the Haringvlietsluices for fish migration ICBR 2-4 november Bonn 1 Kees Storm 1, Joost Backx 2 en André Breukelaar 2 1) Rijkswaterstaat Zuid-Holland en 2) RIZA
ICBR 2-4 november Bonn 2 Overview of the presentation Intro Rhine-Meuse estuary & Haringvlietsluices Environmental Impact Assesment Alternative management of the sluices Conclusions
ICBR 2-4 november Bonn 3 Rhine-Meuse estuary Basin 120.000 km2 Average discharge Rhine 2200 m3/s Meuse 230 m3/s Delta 40.000 km2 50% below sea level 3 water bodies: Haringvliet (80 km2) Hollandsch diep (38 km2) Biesbosch (10 km2) Total length 64 km Max. depth 5-12 m.
Why building sluices and barriers? ICBR 2-4 november Bonn 4 1953 storm flood disaster (> 1800 people killed) Delta project (1958) dike strengthening closure of coastal inlets
Delta project ICBR 2-4 november Bonn 5
ICBR 2-4 november Bonn 6 and the Haringvlietsluices (1970) mouth of Haringvliet 3 km wide dam (2 km) and sluices (1 km) 17 sluice gates Each 60 m wide and 5 m high
Salt gradient & Tidal range ICBR 2-4 november Bonn 7 Before 1970 Present situation Low tide and high discharge Rotterdam Rotterdam Hellevoetsluis Hellevoetsluis Middelharnis Dordrecht Middelharnis Dordrecht Salinitity in 0/00 N High tide and low discharge 0-0.5 0.5-5 5-18 > 18 rest wate rs 0 2 4 6 8 10 Kilome te rs Ministerie van Verkeer en Waterstaat Dir ectoraat-generaal Rijkswaterstaat Rijksinstituutvoor Integraal Zoetwaterbeheer en Afvalw aterbehandeling RIZA Rotterdam Hellevoetsluis Middelharnis Dordrecht
Consequences of the construction for the Haringvliet estuary ICBR 2-4 november Bonn 8 Before tidal range 1.8 2.3 m. salt/brackish/fresh free fish migration mudflats and creeks reed beds rushes and willows After tidal range 0.3 m. fresh water body fish migration disabled fresh water fish washed out bank erosion willows and nettles water for agriculture & drinking-water water recreation
ICBR 2-4 november Bonn 9 Fish species (guilds) Number of species per ecological guild Historical Present (1995-2000) Diadromous Estuarine resident Freshwater Marine (juvenile) Marine (seasonal) TOTAL 12 20 27 16 20 95 9 1 38 0 1 49
Alternative management Haringvliet sluices ICBR 2-4 november Bonn 10 In line with the national integrated water management policy an Environmental Impact Assesment (EIA) was carried out from 1994 to 1998 aiming: to restore the natural transition between river and sea to ensure sustainable use of waters on both sides of the sluices no adverse effect on flood protection
ICBR 2-4 november Bonn 11 Conclusion EIA 1. For a sustainable rehabilitation of estuarine biota, the Storm Surge Barrier alternative would be best present Sluices Ajar 2. The negative effects of the alternative management regimes could all be offset by compensatory measures Controlled tide 3. Controlled tide the preferred option (best balance between cost and ecological benefits) Storm Surge B.
ICBR 2-4 november Bonn 12 Sluices Ajar a balancing act Optimizing effect on ecology with maximum opening during flood and ebb periods & controlling salt intrusion and preventing significant effect on fresh water supply
ICBR 2-4 november Bonn 13
ICBR 2-4 november Bonn 14 Fish migration guilds Position Timing during tide Sea trout Low+High Alosa Pelagic Herring High Smelt Migrating species Demersal High Low+High Whiting Lamprey Sturgeon Benthic High STT Flatfish Goby J. flatfish elver
ICBR 2-4 november Bonn 15 Moment of fish migration Vissoort M igratie W ijze Periode jan feb mrt apr m e i jun jul aug sep okt nov dec Schol (juv) 6 0 0 0 Spiering 2 0 0 0 Haring (juv) 2 0 0 0 Sprot (juv) 2 3-D. Stekelbaars 2 Puitaal 5 A a l 4 0 0 0 Schar (juv) 6 Tong (juv) 6 0 0 0 Dikkopje (adult) 5 Zeebaars 3 0 0 Zeeprik 4 Fint 1 0 0 0 Elft 1 0 0 0 Steur 4 Bot (juv) 6 0 0 Ansjovis 2 0 0 0 0 Steenbolk 3 Diklipharder 3 0 zandspiering 5 Smelt 5 Tong 5 0 0 0 Dikkopje (juv) 5 Kleine zeenaald 5 Schar (adult) 5 0 0 Schol (adult) 5 0 0 0 Slakdolf 5 Vijfdradige meun 5 W ijting (juv) 3 Zeeforel 1 0 0 0 0 0 0 Zalm 1 Houting 1 Harnasmannetje 5 Sprot (adult) 2 0 0 0 Rivierprik 4 Zeedonderpad 5 0 0 Kabeljauw (juv) 3? 0 0
ICBR 2-4 november Bonn 16 South side preferred to open first Net tidal current Shipping channel Natural habitat and refuge
ICBR 2-4 november Bonn 17 Sluices Ajar in 2008?! Controlling factors: marginal lowering of water levels restricted salt intrusion & network to monitor salt set up network to monitor changes in ecosystem draw up protocols with water boards and water supply companies Compensation: relocating intakes for drinking and agricultural water
ICBR 2-4 november Bonn 18 Next step: towards Controlled tide? evaluation of Sluices Ajar after 5 years in operation (2013) new political decision for a possible further step towards Controlled Tide for restoration of tidal habitats for estuarine fish
ICBR 2-4 november Bonn 19 Conclusions Closing off the Haringvliet has had a major impact on estuarine ecology Partial restoration is possible with alternative sluice management (sluices Ajar) In 2008 Haringvlietsluices will open also during flood period; diadromous fish should benefit the most restoring the ecological continuum, it is an important measure in the implementation of the Water Framework directive
Thank you for your attention! ICBR 2-4 november Bonn 20