The Feather River Fish Hatchery is a very important site in the city Oroville, so there definitely needed to be a cache placed here. Here is some background information about the hatchery:
"Feather River Hatchery raises Chinook salmon and steelhead along the Feather River, just below Lake Oroville. An underwater viewing window displays migrating salmon or steelhead during the approximate dates of mid-September through June. Visitors will enjoy their time at Feather River Hatchery any time of year and great fishing is available on Lake Oroville and several nearby rivers.
The Feather River Fish Hatchery is divided into 2 sections. The fish barrier dam, observation platform and underwater viewing are located on the east side of Table Mountain Boulevard. The underwater viewing windows are best for viewing fish from mid-September through June. The spawning room, hatchery and rearing ponds are located on the west side of Table Mountain Boulevard. Salmon spawning operations can be observed Monday through Friday beginning mid-September until mid-November. Steelhead spawning can be observed mid-December through mid-February. Fish are present in the rearing ponds all year. The annual Oroville Salmon Festival is held on the 4th Saturday of September at the Feather River Fish Hatchery and downtown Oroville."
Source -https://www.wildlife.ca.gov/Fishing/Hatcheries/Feather-River