- disruptive and diverting element are placed in a riverbed with the main objective to redirect, disturb, divert and deflect the current and initiate water dynamics

- elements: larger single rocks

- sometimes arranged in groups of several rocks, larger tree trunks, willow branches (for groynes)

- the elements can be placed near the river bank or in the middle of a river, depending on the desired effect (deflecting and redirecting the current, one-sided riverbank erosion, sediment accumulation)

- measures lead to flow variation and sediment shifting processes

- disruptive elements influence the development of the channel (length, depth)

- flow sediment variation; development/settlement of water-dependent habitats

- provide space for human interaction/playing/relaxing

- provide habitats for aquatic animals, small animals (bird, insects) tree trunks and stones

- Tree trunks with or without branches

- either fixed in the riverbed, positioned with piles or steel cables

- if trunk is fixed only at one point  free floating of tree trunk in the current

- trees pointing downstream or horizontal to flow direction

- stones and trees can serve as stepping stones for public purposes and as a place to play

- stone type variation; often application of local available stones

- aesthetic value of elements bioengineered groynes

- general objective of the following measure is to disturb, divert and deflect the current away from the riverside/riparian for riverside protection against erosion

- groynes mainly consist of willow (whole plants or branches) or bundles of brushwood (fascines)

- roots of living willow and fascines grow vertically as well as horizontally and form relatively stable, natural constructions

- initial construction of e.g. willow (pioneer species) is naturally extended through a gradual establishment of other/different shrubs

- the naturally grown construction provides a habitat for various organisms and aquatic animals

Basic information

Type: 
Retrofitting + Creation

Performance

Evapotranspiration none none
Shading none none
Reflection (Albedo) none
Water Conveyance 1
Water Infiltration 1
Water Retention 1
Water Storage none
Water Reuse none
Water Filtering 1
Water Bio-remediation 1
Deposition none
Bio-filtration none
Habitat Provision 1
Connectivity 1
Beauty / Appearance 1
Usability / Functionality 2
Social Interaction 2
Role of Nature / Mode of Action: 
- Replication of natural river channels with varying depth and width; natural elements (e.g. stones) and vegetation within and at the river and at its riversides. - replication of natural conditions (e.g. bushes or trees with branched roots) at the riverside that stabilizes the soil, protects the river zone from erosion and slowdown water velocity - natural processes occur (filtering, storage, infiltration)
Technical & Design Parameters: 
Different elements are possible: stones, tree trunks, willow-groynes - stones with sufficient size and weight to guarantee their stable position in the riverbed - often used: local rocks - Single rocks or group of rocks - Materials for groynes: living willow, willow branches or fascines (pioneer plants) - willow branches are arranged diagonally - extension of the system through a natural establishment of different shrubs - variable construction: extension of living system with stones and other materials that leads to a higher construction stability  suitable for strong currents and large groynes - limited use of living plants/willow because of limited stability in rivers with strong current - different groynes layout and orientation possible (pointing upstream, downstream or to flow direction) - Provide space for human interaction/playing/relaxing - Provide habitats for aquatic animals, small animals (bird, insects)
Conditions for Implementation: 
- Construction type of groynes depends on strength of the current and the size of the groynes (e.g. living plants; additional stones)
Benefits & Limitations: 
Benefits: - redirection and deflection of the current - habitat for organisms, birds and aquatic animals - reduction of water velocity (at the shore zone) - protection against flooding - provide space for human interaction/playing/relaxing

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 730052 Topic: SCC-2-2016-2017: Smart Cities and Communities Nature based solutions