On the 26 February 2024, ANCOLD and Water Corporation hosted a site tour of North Dandalup Dam and Logue Brook Dam. There were 30 attendees from across the dam industry in WA, with designers, constructors, asset managers and operators of water and tailings dams from both the public and private sector.
The first stop was North Dandalup Dam, where investigation work is underway to identify the cause of a sinkhole which developed on the crest of the dam and to confirm the arrangement of critical downstream filters at the transition between the rockfill and earthfill embankment sections. After a tour of the dam, which included a peek into the intake tower, where a live demonstration of the torpedo lifting equipment (which allows for remote latching and detaching of submerged screens and dead plates) was given, we safely entered the excavation near the right abutment. Within the excavation we had a great cross-sectional view of the core and filter arrangement, and we could also identify clear lamination of the core material along the lift layers (likely caused by scraper tracks which were not scarified or punched through by the rollers of the 835’s used to compact the fill). The evidence suggests that the sinkhole formed from internal erosion caused by issues with the dam crest surface drainage system and from deformities caused by tree root systems. An important lesson to all dam operators and asset managers to not let vegetation take hold on dam embankments! The dam embankment will be rebuilt with the new chimney filter now extending all the way to the top of the dam.
It was then on to Logue Brook Dam, with a stop along the way at the Pinjarra Bakery for an all expense paid for lunch! We were able to experience the hive of activity occuring at the saddle dam where work is underway to construct blanket and chimney filters combined with a new flatter downstream embankment slope. The aim of these works is to address known piping and stability risks.
A big thank you to all the Water Corporation employees who helped organise the day: Alex Gower, Michael Smith, Jeremy Roberson, Alex Greenacre, Leanne Pearce, Aat Van Schie, Jordan Grljusich and Kai Kinkella. Our expert guides ensured the day was informative, safe and fun for all.
Author: Daniel Minson – Senior Engineer, Water Corporation
ANCOLD is an incorporated voluntary association of organisations and individual professionals with an interest in dams in Australia.
