Demo site 1

Iller River - Germany

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Hydrograph:
The following graph shows changes in the rate or velocity of the flow in this section of the Iller River. This value is given as a volume of water per second. On average about 46 m3 of water pass through every second. During drier periods, the mean flow rate averages out at about 9 m3/second. On the other hand, high levels of rainfall may bring the mean flow rate up to as much as 829 m3/second.

 

Sediment management:
Artificial gravel input

While gravel naturally deposits along river shores, it can also be introduced manually to manage the sediment balance along a river. This work started with the ISOBEL project which you can find resources about in the description below the map [2].

The Danube River near Budapest

Sediment management:
Manual gravel input

While gravel naturally deposits along river shores, it can also be introduced manually to manage the sediment balance along a river. This work started with the ISOBEL project which you can find resources about in the description below the map [2].

HydrEcoSedimentary tool (HEST):

The HEST approach helps researchers understand hydro-sedimentary processes. Read more about tool in the description below the map [1].

Fish passage:

Nature-like fish passages as a habitat for fish to spawn.

Sediment management:
honeycomb and arc-shaped structures

Honeycomb and arc-shaped structures made of large boulders were implemented in the Iller River to reduce gravel erosion and stabilize the riverbed. These in-stream structures act as large roughness elements, modifying local hydraulics by inducing flow separation, turbulence, and recirculation zones, which promote sediment retention and redistribution. This work started with the ISOBEL project which you can find resources about in the description below the map [2].

Exposed sandstone:

In these sections, the riverbed sediments have been almost entirely eroded which is shown as exposures of bedrock. But sediment management measures, including structural elements and gravel deposits, have significantly improved the conditions.

Problem

The Iller, a major tributary of the Danube River, represents a heavily hydropower-regulated site where dynamic sedimentary transport processes are disrupted, impacting the habitat availability and quality for key freshwater species.

Our response

Integration of sediment monitoring through innovative tools; implementation of sediment measurements and reservoir operations and assessment of their efficiency to reestablish sediment dynamics. Both field-based and hydrodynamic modelling assessments will be used to improve measures and inform future solutions.

Stakeholder involvement will play a crucial role in the implementation stage, and its success will lie on the well- established stakeholder involvement structures in the region, such as the Steering Committee for the Iller Strategy, and past European projects such as the LEW-led LIFE Isobel Program.