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River Skjern: Presentation of speaker 1 Mogens Bjørn Nielsen Geomorphologist Hydrologist Head of Rivers, Landscape and Planning Department in the Region.

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Presentation on theme: "River Skjern: Presentation of speaker 1 Mogens Bjørn Nielsen Geomorphologist Hydrologist Head of Rivers, Landscape and Planning Department in the Region."— Presentation transcript:

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2 River Skjern: Presentation of speaker 1 Mogens Bjørn Nielsen Geomorphologist Hydrologist Head of Rivers, Landscape and Planning Department in the Region of Aarhus Experience includes: River Skjern: project steering and projecting River Brede: Project leader The EU-Life River Restoration Project with UK: Project leader In 15 years responsible for the sea dike to the Wadden Sea and river dikes in the Region of South Jutland

3 River Skjern, Denmark Background: River Brede – example on benefits for biodiversity Aims and considerations in the River Skjern Nature Project The challenge in projecting to secure flood defence with nature benefits The results in the field The democratical process

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5 R. Brede: Before EFC = regulated

6 R.Brede Restored In the back and still regulated in the front

7 R.Brede The meadows as water reservoir at high discharges

8 EFFECT ON FLORA other species Wetland-species Number of species North riverbankSouth riverbankBoth riverbanks Number of species of riverbank plants on the two riverbanks of River Brede before and after restoring.The river was on this reach restored in late 1994 between the investigations in summer 94 and summer EXAMPLE RIVERBANKS PLANTS

9 EFFECT ON FLORA other species Wetland-species Number of species Area 1Area 2Area 3 Number of species on 3 areas along River Brede before and after restoring. The river was on this reach restored in late 1994 between the investigations in summer 94 and summer 95. -EXAMPLE MEADOW PLANTS

10 Geography North Sea region Coastal humid climate Lowland Intensive farming

11 Skjern River Catchment: 2500 km 2 Discharge: m 3 /sec 5000 t N/year 100 t P/year 30,000 t sediments/year The lower part regulated and diked in The “inland delta” drained for intensive farming

12 River Basin and Project Area

13 Regulation scheme

14 Objectives Restore meandering and natural dynamics and secure against flooding outside project area Improve conditions for flora and fauna Ensure high water quality in the river system and the Fjord Improve the basis for outdoor leisure

15 From regulation to restoration Regulation and drainage 1800: Inland delta: 4000 ha of wetlands, unique in Denmark 1900: Small scale regulation starts : Main regulation and drainage scheme : Increasing environmental concern Restoration 1987: Parliament decision: The river to be restored for self-purification 1988: Grants for land acquisiton 1995: Detailed surveys and design started 1998: Public works act 1999: Earth works started 2002: Restoration complete

16 Environmental Concerns Nature lost A unique riparian system Part of a major migration corridor Poor conditions for Salmon and Whitefish Biotopes of rare species disapered Pollution Ochre Nutrient leakage No retention Farmer’s concern Land shrinkage

17 Design Considerations Land shrinkage large areas now lower than the river and even below sea level either let the river flow through shallow lakes and restore the inland delta by time or restore it separated from lakes and wetlands by levés Decreasing earth works Landscape priorities Using existing dikes for delimitation where possible Using existing bridges Protection of sensitive flora and fauna Utilisation of old meanders Authenticity

18 Construction and earth works 2 new bridges Road to be elevated 5 bridges decommissioned 2 pumping stations decommissioned Dikes to be removed Re-meandering Total earth works: 3 million m 3

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20 Before: Highway for water bordered by dikes

21 Before: Secondary drainage channel

22 R. Skjern ready to bend again

23 Before

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25 Nature areas and intensive farmland side by side

26 The tributary R. Omme also restored

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29 Discharge

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32 Total earth works: 3 million m 3

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41 Know how on restoration - t he art of restoration and aesthetic - authenticity/originality - the physical dimension - the biological dimension the hydrological dimension Democratical process

42 Know how on restoration - t he art of restoration and aesthetic - authenticity/originality - the physical dimension - the biological dimension the hydrological dimension Democratical process Political dimension - protect environment and nature - quality objectives for streams, lakes and coastal waters - NGO’s and interest groups - Investments - Public interests Regional plans and goals

43 Know how on restoration - t he art of restoration and aesthetic - authenticity/originality - the physical dimension - the biological dimension the hydrological dimension Democratical process Political dimension - protect environment and nature - quality objectives for streams, lakes and coastal waters - NGO’s and interest groups - Investments - Public interests Regional plans and goals Landowners - private landownership - involvement - negotiations - compensations exchange of land

44 Know how on restoration - t he art of restoration and aesthetic - authenticity/originality - the physical dimension - the biological dimension the hydrological dimension Democratical process Political dimension - protect environment and nature - quality objectives for streams, lakes and coastal waters - NGO’s and interest groups - Investments - Public interests Regional plans and goals Practical dimension - project management and leadership - tenders contractors Goals Success criteria Methods Cooperation Time & budget Quality assessment Landowners - private landownership - involvement - negotiations - compensations exchange of land

45 Recommendations on lowland stream restoration Include consideration on the catchment area and the whole stream valley in the project plan Secure the hydrological connection between the stream and its valley. Establish many crossings between the straight, regulated course and the new meandering, restored course, in order to secure rapid colonisation by aquatic plants and other organism Restoration projects involving excavation of the former floodplain must take into consideration existing vegetation niches worthy of preservation. Restoration of streams by means of large-scale excavation should start during periods of low discharge (in Denmark this period is July to September). The construction work should be finished before the spawning season for trout and salmon occurs late in autumn.

46 How to gain the most ’nature’ for the invested money in restoring streams and wetlands 1.Stable investments and long-lasting projects 2.Low costs to buy areas and laying out the project 3.Low cost to maintenance after completion 4.Large areas better than spots 5.Several purposes at the same time 6.Political and local back-up 7.Cooperation between authorities and ‘interest groups’

47 A way to better ecosystem in streams and wetlands Prevention is better and cheaper than treatment 1.Stop the accident 2.Preserve what still is in a natural condition 3.Stop drainage and further regulation 4.Proper maintenance and recreational use 5.Use market economics: Socio-economic effects plus links to agricultural land-use and subsidies 6.Rehabilitation and restoring when 1 to 6 have been considered and used International cooperation is necessary


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