Large Pipes for Oregon Gulch Bridge reveal plans of new access route(s) for emergency construction of the Spillways. A west approach on the north side of the Feather river optimizes access to the three main focus areas of construction. The Lower Main spillway + plunge pool, the Upper Main spillway, and the Emergency Spillway. This access side will also be where the large dredge pilings of material reside. Portland Cement mix & other supplies could travel in volume from the new access side without threatening the critically sensitive spillway bridge. The current use of the spillway bridge, by heavy construction trucks, are limited to near 5mph an only one vehicle at a time. It would be a wise choice to eliminate the wear & tear in flexure loads on this critical bridge. Any failure of this bridge would threaten the structural integrity of the Radial Gate headworks.
The new access routes likely will require addressing an issue of dust of which residents of Oregon Gulch Road have been complaining about. That is, if that road is chosen as a main access route. The other option is upgrading the road on the north side of the Feather River. That road may take a bit more work to upgrade than the upper route. It's possible that both routes will be used to facilitate alternate travel & coordinated staging arrival. I wonder if DWR has notified residents of what they may be in for…
The Old (existing) access routes on the southern side of the Feather River would facilitate access to the south side of the upper main spillway, such as large cranes for Upper Spillway work. Having two "sides" for strategic equipment allows for less congestion. One example: Prefabrication of on-site items may be done on the south side with cranes lifting these items in place in the Upper Spillway chute work area.
ES bridge 1 and ES bridge 2 are the critical dependencies. Will they leave these as "fill" bridges? If so, a "shut down" of the main spillway would force the emergency spillway to activate if snowmelt outpaces the Hyatt power plant outflow. This would damage or destroy the "fill" bridges - only to be quickly re-filled if the emergency spill doesn't escalate in size and create more disruption.
These plans strictly depend on the cooperation of nature.
