Oct. 25, 2021
Dear East 40th Neighbors,
Following is a round-up of recent activities on the water storage project, information about stormwater management, and FAQ on controlled underground blasting.
What’s been happening at the site?
Third-party pre-blast home inspections are nearly complete. TerraFirma will email the reports directly to homeowners this week.
The additional, unplanned work to reduce the slope angle on the west side of the site is complete (see Oct. 7 email for more information).
Excavation of topsoil around Tank #1 (east side) is nearing completion. Excavation for Tank #2 (west side) is about 60% complete.
Drilling is beginning this week. Drilling hours are anticipated to be 7:30 a.m. to 5 p.m. M-F. We expect this will be the noisiest phase of the project and will last 6-8 months.
Blasting is tentatively scheduled to begin this Thursday (10/28) at 1 p.m. The first blast will be a small, test. Starting next week, blasting is expected to take place on Tuesdays and Thursdays between 1-1:30 p.m.
Six seismographs/vibration monitors have been installed around the perimeter of the site.
In the next couple of weeks we will be installing a temporary construction power supply. The new conduit will be bored from an electric box near 4065 Hilyard St. There could be traffic impacts on Patterson St. that day.
Benches are here! We will be putting two on the west side of the construction site and one on the east side to provide a place to watch the construction.
Detention pond collects runoff
Just in time for the rainy season, a detention pond has been built to collect runoff from the site. Water is funneled to this low spot and treated with a chemical called Chitosan which works as a flocculant, binding sediment together in a mat which then settles out in the pond. Clean water is then discharged via a pump to the City’s storm system.
For now, the pump is being operated by a diesel generator, which will be noisy when running. Once power is supplied to the site, the pump will be run off electricity.
Eventually the pond will be replaced by a permanent rain garden/swale that will collect runoff from the site and discharge it to a newly constructed stormwater system. Long term this will have the same function as the pond but will not require pumping and will flow by gravity to the City’s stormwater system.
EWEB, the contractor and City staff continue to work together to adjust and improve stormwater management. The switch from dry weather best management practices (BMP) to wet weather BMPs is causing some mud build-up on Patterson St., and we have requested a meeting with the City so that we can make adjustments that align with our erosion control permit.
The contractor is sweeping Patterson Street multiple times a week to keep mud to a minimum. We have asked the contractor to move the “biobags” during street cleaning and then replace them afterward. This should help keep bags and surround areas a little neater.
Underground Controlled Blasting FAQ
What is underground blasting?
Underground controlled blasting is a common infrastructure construction method used to break rock for excavation. Holes are drilled into the rock for placement of the blasting agent. Packed dirt is added to holes and above the rock. A seismograph records blast vibrations to verify they are within specifications.
Is it safe?
Yes. Controlled blasting is highly regulated and conducted using safe methods and procedures by trained professionals. Blasts will be monitored by seismographs to maintain acceptable levels of ground motion in conjunction with vibration controls. Each blasting event will occur only after verification of all safety precautions and the site is deemed cleared and secure by the blaster-in-charge.
What can I expect to hear/see/feel?
Air horn safety signals will sound 5 minutes and 1 minute before the blast and at the conclusion of the blast. In addition to the air horn, those very near to the construction site may feel a vibration comparable to a door slam or a large truck driving down the street.
Dust suppression systems and heavy blasting mats will be in place to minimize vibration and debris.
Watch an example of controlled underground blasting.
When will blasting occur?
Blasting activity will likely begin the second or third week of October and continue for approximately six months. Current plans call for a blasting event once a day between 1-1:30 p.m. on Tuesdays and Thursdays. The blasting schedule is subject to change and to the extent weather or project schedule necessitates blasting outside of those times, blasting would occur during daylight hours Monday through Friday. No blasting will be performed weekends or federal holidays.
What should I do to prepare?
Residents living adjacent to the project site may wish to keep windows closed for the brief period of the blasting, between the one-minute signal and the following all-clear signal. If you are near the construction site and hear an air horn, please be aware blasting activity will occur shortly and follow instructions of site personnel or any additional signage that may be posted.
Water Storage Improvement Projects
Access to clean water is vital to our community. EWEB is hard at work making sure safe, reliable water continues to flow even as critical infrastructure ages and new challenges arise. In the next decade, we plan to construct new water storage facilities near 40th Ave. and Patterson St. and replace the water storage systems at EWEB’s College Hill and Hawkins Hill sites. The projects will be built to seismic and contemporary operating standards, providing more than 40 million gallons of resilient, safe water storage.
Contact us with questions
If you have questions or input, please don’t hesitate to reach out to the project team at
541-685-7899 or email@example.com. Emails sent to this address will reach:
Laura Farthing, Project Manager/Senior Civil Engineer
Jen Connors, Communications Supervisor
Jeannine Parisi, Customer Relationship Manager
Wally McCullough, Water Engineering Supervisor