What were the original and revised estimates based on?
The original spill estimates were made by City staff and contractors based on the capacity of the pipe, field observations that were limited due to conditions, and very rough estimates of the time it would take to make repairs. Revised estimates were based on flow meters, pump capacity, pump run-time, and the duration of the spill. One key factor in this event is that more wastewater was being conveyed through the leaking area to the treatment plant than was originally expected. The Orange County Health Care Agency uses the initial estimates to conservatively determine beach closures and revises the closures as more information is available.
What exactly broke and where?
A valve assembly on the main pipeline failed about one-quarter of a mile from the Coastal Treatment Plant in Aliso Canyon along the edge of the golf course. The spill had nothing to do with The Ranch or its operations.
What caused the spill?
Although the investigation is ongoing, the initial assessment is that a valve assembly failed due to long-term corrosion.
When did the beaches reopen?
The Orange County Health Care Agency lifted the closure order on December 2, 2019. This press release offers more information: http://www.lagunabeachcity.net/civica/press/display.asp?layout=1&Entry=698