Project Description
Spillways: In the wake of 2017 failure of the Oroville Dam Spillway, the Division of Safety of Dams (California Department of Water Resources) is requiring owners of high-hazard dams to conduct a comprehensive study of their spillways. PID has two spillways affected by this requirement: one each at Paradise Lake and Magalia Reservoir. Following the detailed analysis, PID will be required to make any required spillway repairs/upgrades that come to light as a result of the study.
Additionally, Magalia Dam, built in the early 1900's and needs rehabilitation.
Magalia Dam, built in 1918 is a hydraulic-filled dam, rated poor by the Division of Dam Safety and at full capacity is considered a high downstream hazard should there be a significant earthquake. Because of this rating, the State Division of Dam Safety (DSOD) limits the reservoir elevation to 2200 feet at a loss of approximately 2000 acre-feet of water storage.
The Paradise Irrigation District is actively working on a design to bring Magalia Dam and spillway back into compliance with the DSOD, as well as widen the top of the dam to allow for future widening of Skyway for future fire evacuation needs (limited evacuation routes were an issue during the Camp Fire). While not in compliance, Magalia reservoir’s storage capacity is limited to 796 acre-feet, a small fraction of its designed volume, which reduces water storage that could be used for fire-fighting efforts. The project is designed to also replace and relocate the spillway to the opposite side of the dam reducing damage risk to the water treatment plant.
Current Design Status
Spending Plan (will be updated to reflect necessary spending as a result of design work in progress)
Project Phase | Previous Fiscal Year Expenses | Fiscal Year 15/16 | Fiscal Year 16/17 | Fiscal Year 17/18 | Fiscal Year 23/24 | Fiscal Year 24/25 | Estimated Future Construction Cost | Total |
Design / Management | - | - | - | $350,000 | $579,912 | $2,000,000 | $6,000,000 | $8,929,912 |
Construction | - | - | - | $100,000 | - | $60,000,000 | $100,000 | |
Total | - | - | - | $450,000 | $579,912 | $2,000,000 | $66,000,000 | $69,029,912 |
Project Manager
- Blaine Allen
Department: Engineering
Funding Source
- folder Operating Fund
- The District is actively seeking financial assistance for this project.
Project Status
Planning
Benefits to PID and its Customers
Increased spillway safety.
Anticipated Project Timeline
Concept Approval |
Planning |
Design |
Construction |
Completion |
June 2017 | May 2017 - Sept. 2017 | current | - | - |
Initial Spillway Study Video
Project Info
- pdf May 2017 - Letter from Dept. of Water Resources ordering dam spillway condition assessments (213 KB)
-
pdf
July 2017 - Board awards contract for the development of spillway condition assessment work plans to Genterra Consultants, Inc.
(6.72 MB)
pdf
(654 KB) - pdf October 2017 - Board awards contract for phase I spillway condition assessment work plan implementation to Genterra Consultants, Inc. (731 KB)
Project details updated December 2017