Project planning services in accordance with § 43 HOAI (engineering structures) in the service phases 2 to 9 of the newly constructed body of water, the inlet and outlet structure as well as the technical planning in accordance with § 51 HOAI (structural design) of the inlet and outlet structure with the service phases 2 to 6 HOAI, as well as local construction supervision for Implementation of the subproject new side arm of the Iller until completion. A phased assignment is envisaged.

The side arm is a newly created body of water on the right side of the Iller (in the direction of flow) over a length of approx. 3 km (flow kilometers 24.5—27.5) at the Altenstadt and Illertissen marquees, thus entirely in the Free State of Bavaria. It starts about 1.4 km north of the bridge of the K7594 and ends about 0.8 km south of the S2018 bridge over the Iller. The area is bounded on the east side by the Iller Canal and the existing path system next to it. The standard runoff in the side water should be 2 m³/s.

The side arm is a newly created body of water on the right side of the Iller (in the direction of flow) over a length of approx. 3 km (flow kilometers 24.5—27.5) in the Altenstadt and Illertissen marquees, thus entirely in the Free State of Bavaria. It starts about 1.4 km north of the bridge of K7594 (Oberbalzheimer Straße) and ends about 0.8 km south of the S2018 bridge over the Iller. The area is bounded on the east side by the Iller Canal and the existing path system next to it. The standard runoff in the side water should be 2 m³/s.

At the beginning, an inlet structure is provided that reduces the amount of water from the iller in the side arm in order to prevent more severe erosion phenomena. At the end, an outlet structure is provided that reduces the amount of water that flows back into the river banks in order to prevent more severe erosion phenomena, in particular after flood events. As part of the Iller Biological Engineering Report, a preliminary design concept was created in which all essential components are shown. This is the basis for further planning.

To design the side arm, perform a hydraulic calculation with HYDRO_AS-2D (special performance).

The Lower Iller is in a moderate to unsatisfactory state according to the Water Framework Directive. The aim of the joint project “Agile Iller” by the state of Baden-Württemberg and the Free State of Bavaria is to restore continuity, connect backwaters and create habitats in the floodplains. For this purpose, the floodplains are to be integrated back into the river landscape and their development is promoted. The water structures are to be improved and the shore areas redesigned. The aim is to achieve the good ecological status or good ecological potential again.

One sub-measure is the side arm.

Timetable: Allocation of planning services mid-2022 (environmental planning will be assigned in parallel)./Completion of approval planning by the end of 2024/approval phase in 2025/Implementation planning and tender documents by mid-2026/Call for tender winter 2026-2027/Construction start 2027/Completion by end of 2028.

The tendering position assumes that the overall cost of the project is €6.3 million.

Further information on the overall Agile Iller project: https://www.agile-iller.de/