Geotechnical survey work inside reservoir
Over the summer months, a contractor for the Portland Water Bureau will be conducting geotechnical survey work in Washington Park. This work is part of the project to make improvements and changes to the two water reservoirs, including installing a 15-million gallon buried reservoir with a reflecting pool on top, generally in the footprint of the existing upper Reservoir #3.
The geotechnical work will involve a crew using equipment to bore deep 12-inch diameter holes in the ground to install landslide monitoring devices that measure ground movement and groundwater depths. Due to the landslide potential around the reservoir sites – dating back to a major slide during the original construction in 1894 – the Water Bureau must explore what steps will be necessary to stabilize the hillside.
The survey work will also obtain sub-surface information necessary for the design of the new facilities. Each boring hole monitoring and sampling will take up to 3 days to complete and then be backfilled. Park users are encouraged to avoid these work areas.
The work is scheduled as follows:
Monday, June 17: Road Closure - SW Sherwood Blvd, from SW Kingston Ave. to SW Sacajawea Blvd. The street will be restricted to local access only, from 7:00 AM to 12 Noon. The closure is necessary to bring in a crane to lower equipment into the reservoir.
Monday, June 17 through Friday, June 21: With Reservoir #3 drained in advance, a crew will perform borings inside the open reservoir.
One day during the week of June 24: Road Closure - SW Sherwood Blvd, from SW Kingston Ave. to SW Sacajawea Blvd. The street will be restricted to local access only, for about three hours.
July to August 2013: Crews will perform geotechnical boring throughout Washington Park, including the parking lots near the Japanese Gardens and tennis courts, a service road, and sites around the perimeters of the two open reservoirs.
If you have any questions, please contact Tim Hall, Public Information, at 503-823-6926. Thank you for your cooperation.
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