Why was Reservoir 3 taken off-line on Saturday when the first result was received on Thursday?
The initial positive result on Thursday afternoon, November 26, showed that there was only potential contamination at the outlet to Reservoir 3. Without resampling results at multiple sites, there was no way to determine whether the initial bacteria that was detected was transient, was from a source in Reservoir 3, or was from a location upstream. Resampling at the outlet of Reservoir 3 and at locations upstream and downstream was performed on Friday. Results received Saturday morning indicated that the source of contamination was not transient and that it was likely within the reservoir. The reservoir was shut down once this information was known on Saturday Reservoir shutdowns present challenges for the water system, including the potential to compromise the availability and pressure of water for customers and for fire flows. Draining of the reservoirs can overwhelm the sewer system and cause sewage overflows to local waterways. The bureau will review its current shutdown practices a