VRT inspected the underwater concrete structures of Lieksankoski and Pankakoski powerplants’ dams in Lieksa river. The inspections took place in July 2018, and the area surveyed was approximately 430 metres. Inspection was performed from VRT’s survey boat and the data was captured with multibeam echo sound.
The same sites have previously been inspected by divers. This time Kemijoki Oy wanted to get firsthand experience on VRT’s surveying method. With multibeam echo sound surveying Kemijoki got a detailed picture of the underwater structures, tells Marko Talvensaari, Chief of Dam Construction and Excavation. It is often difficult to get as wide a picture by diving and it may require downtime in the powerplant.
Gisgro as planning support
The survey data was delivered to Kemijoki Oy through Gisgro online service. Gisgro enables examining the 3D reports without having to install any software or experience on handling point cloud data.
The reports were found to be good and the observations interesting. Kemijoki Oy got information new to them about the underwater structures. For example, knowing the sediment drifts gives them the opportunity to prevent many problems from occurring. The reports showed all the observations with their severity classifications and locations in addition to the overview.
Talvensaari tells that Kemijoki Oy used Gisgro also for planning in the Anjalankoski dam in Kymi river, and that it served the purpose well.
If the inspections are to be repeated in couple of years when they become current again, it will be easy and handy to compare the survey results in Gisgro.
Traditional Finnish energy company
Kemijoki Oy was founded 1954. Year 2017 Kemijoki Oy’s power plants together produced approx. 4900 GWh of electric energy, of which 145 GWh was produced in the Lieksa river hydropower plants.
The dam safety in the hydropower plants of Kemijoki Oy’s dams’ is monitored regularly and VRT’s inspections are one example of the inspection routines.
Read more about Kemijoki Oy: https://www.kemijoki.fi/en/kemijoki-oy-in-brief.html
“VRT’s method gives a demonstrative and comprehensive view to the condition of underwater concrete structures.”