Shon Sheffrey Dam Willowstick Survey - Case Study
Atkins used Willowstick to design targeted grouting and successfully stop leakage through earth embankment dam
Atkins was commissioned by Welsh Water to reduce leakage at earth dam nicknamed “the sieve”. Client admitted they would need to come up with a new name after Atkins successfully located and stopped all leakage pathways with a Willowstick assisted grouting programme.
Significant leakage through earth embankment
Shon Sheffrey Dam is a 260m long clay core embankment dam. The dam built in the late 19th century was raised in the 1940s. There was a long history of significant leakage at the dam, especially near the right abutment which increased to critical levels triggering the need for remedial works.
Atkins was asked to identify the location of the leakage paths using Willowstick and following this carry out detailed design of the grouting works.
Willowstick successfully used to pinpoint grouting works
The Willowstick survey successfully detected a number of discrete leakage pathways through the dam and along the spillway. Atkins then used the Willowstick results to design and supervise targeted grouting works at the dam. After the grouting works were completed all damp spots on the embankment successfully dried up and a CCTV survey of the leakage drains identified they were both clear and dry.
The Willowstick survey identified the exact path of the leakage through the embankment in to the spillway and tunnel areas, which enabled the remedial works to be accurately focused on the affected areas.
The survey found no additional areas of leakage through the embankment, providing the client with confidence that the leakage through the dam had been dealt with.