Why are functioning stream crossings so important? Streams are ecological corridors in the landscape. In addition to the biological life in the water, the terrestrial surrounding of the streams are used by insects, birds and wildlife.
Most aquatic species require continuity in the streams in order to spread and reproduce. Fish migrate between spawning, nursery and feeding areas. Bottom-dwellers, just like the fish, are dependent on the ability to move along the the streams.
The terrestrial animals that move along the streams, such as otters, need to be able to pass the road crossings without getting killed by traffic.
The goal for the project is to
- Address 304 migratory barriers; 13 otter measures, 260 culverts and 31 dams. Large water areas are thus made available to the designated species
- Build two demonstration areas
- Spread information on the project through printed information material, websites, signs
- Organize training sessions and information meetings
Which are the problems?
There are several factors that can create ecological problems when building a stream crossing:
- High water velocities
- Long culverts without resting places
- Too shallow water within the culvert
- Free fall at the culverts outlet
- Bridges and culverts without natural shores forces terrestrial animals to cross the road or chose to deviate from the stream
How do we solve these problems?
There are several different ways to remidiate migration barriers. Problematic culverts/bridges can be addressed with some of the following solutions:
- Replacing culverts with arches or bridges
- Replacing culverts with larger culverts
- Lowering existing culverts
- Raising the water level in the culvert through building weirs downstreams
- Construct shores or shelves under bridges for terrestrial animals
- European network for valuable nature and protected species
- Contribute to biodiversity within the EU
- The Habitats Directive and the Bird Directive guidance - To maintain the designated natural habitats within the Natura 2000 area - To designate species within Natura 2000 areas with long-term goals in mind
Natura 2000 is a European network for the preservation of natural heritage and protected species, which contributes to biodiversity within the EU.