Hydropower plants
Run-of-river power plants along the Isar (Mittlere Isar, Pulvermühle, Uppenborn works, among others). Inspection of the intake structures, trash-rack installations, weir bodies, stilling basins.
Waters · River
Underwater Inspection at the Isar — Munich Area and Pre-Alps
The Isar, a pre-Alpine bedload river between the Karwendel and the Danube confluence near Deggendorf, is shaped by hydropower development and flood-protection structures. ScanSustain inspects hydropower plants, weirs, bridges and bed-protection structures ROV-based — diver-free. Power-plant deployments require a coordinated shutdown. Actual deployments are subject to approval by the responsible local authorities, facility operators and shipping administrations.
Characteristic Structures
These structure types can be inspected ROV-based at the Isar — subject to approval from local authorities and operators:
Bridge piers
Munich city bridges and bridges in the Isar corridor. Inspection for scour, current damage and bedload loading.
Bed ramps and bed-protection structures
Protective structures against bed erosion along the course of the Isar. Inspection for stone displacement and ramp-toe erosion.
Flood protection
Bank and longitudinal structures, polder structures, confluence areas. Inspection of the water-side components.
Typical Damage Patterns
What can be professionally captured at the Isar — a structured overview of the locally typical damage patterns:
Bedload-induced scour
High bedload freights (Karwendel tributaries) lead to local bed erosion at structure footings.
Bed-ramp erosion
Ramp toes are prone to erosion from following bedload and flood events.
Flood-consequence damage
Riprap displacement, washed-out structural components, bedload deposits after heavy rainfall — structured as-built capture as a basis for rehabilitation planning.
On-Site Methodology
Isar water is clear in winter (up to 3 m visibility), turbid in summer due to glacial meltwater and bedload (0.3–0.8 m). Sonar as the primary method in turbid water, ROV optics in clear conditions. The deployment window is extended into late autumn and late winter.
Water Conditions and Deployment Depths at the Isar
Unlike a lake, a river has no uniform depth — deployment planning depends on the respective structure and the current discharge and flow conditions.
Seasonal visibilities
Isar water is clear in winter (up to 3 m visibility), turbid in summer due to glacial meltwater and bedload (0.3–0.8 m). The deployment window is accordingly extended into late autumn and late winter.
Bedload and current
During active bedload movement, sonar is the primary method. Bedload capture is carried out in a structured way with multibeam sonar; ROV optics is used preferentially in clear conditions.
Exact water levels, flow conditions and visibilities vary depending on discharge, season and power-plant operation. For projects with accuracy requirements, we coordinate the current situation in advance with the operator or the water-management authority.
Survey & Mapping at the Isar
Beyond pure condition inspection, power-plant operators, water-management authorities and flood-protection associations at the Isar are increasingly asking for geometric data — for example for scour-depth measurement at bridge piers, bed-profile mapping after flood events, or the as-built documentation of bed ramps and bed-protection structures. With Survey & Mapping, ScanSustain offers photogrammetric and multibeam-sonar-based capture that delivers depth profiles, site plans and 3D models in CAD/GIS-ready formats.
At the Isar, the strongly fluctuating visibility — from up to 3 m in winter down to 0.3–0.8 m in the turbid summer water — calls for a water-level-dependent method mix: the multibeam-sonar share carries the main part of the geometric data capture during active bedload movement and turbid summer water, complemented by photogrammetric imaging in winter clear-sight conditions. This combination is particularly relevant for bridge piers, bed ramps and flood-protection structures when a geometric baseline is needed for rehabilitation or monitoring.
Regional Authorities and Bodies
Munich Water Management Office, Weilheim Water Management Office, Landshut Water Management Office. Bavarian State Office for the Environment. Power-plant operators: Stadtwerke München, BAYWA Re, Uniper.
Frequently Asked Questions
Are inspections possible during power-plant operation?
No. ROV deployments on machinery installations require a coordinated shutdown. Bridges and bed-protection structures can be captured during ongoing operation.
How is bedload taken into account?
During active bedload movement, sonar is the primary method. Bedload capture is carried out in a structured way with multibeam sonar.
What response time is typical?
Isar corridor Munich: approx. 2 hours. Middle Isar: 1.5–2 hours. Karwendel upper reaches: 3 hours.
Does ScanSustain also offer survey and 3D mapping at the Isar?
Yes, as part of Survey & Mapping — currently as a pilot service, with photogrammetric and multibeam-sonar-based capture for depth profiles, site plans and 3D models in CAD/GIS-ready formats.
Does an ROV deployment at the Isar require official approval?
As a rule, yes. Depending on the section, the responsible bodies are the Munich Water Management Office, the Weilheim Water Management Office or the Landshut Water Management Office, and above them the Bavarian State Office for the Environment. At power-plant installations, coordination with the respective operator (e.g. Stadtwerke München, BAYWA Re, Uniper) is additionally required.
Why does visibility at the Isar vary so strongly between winter and summer?
In winter the Isar carries clear water with up to 3 m visibility. In summer, glacial meltwater from the Karwendel and the associated bedload freight cause turbidity down to 0.3–0.8 m. The deployment window for ROV optics is therefore extended into late autumn and late winter; outside these periods sonar is used primarily.
Plan a deployment at the Isar
Describe your use case — within 1 to 3 working days you will receive a concrete initial assessment with method selection and an effort indication.