Freezing Level Forecast Error Can Consume Reservoir Flood Control Storage: Potentials for Lake Oroville and New Bullards Bar Reservoirs in California
Abstract
The atmospheric freezing level (ZFL) determines the rain‐snow transition zone at the surface, how much rainfall is available for runoff, and the flood risk during a precipitation event. An accurate ZFL forecast is thus critical for reservoir operation, especially in mountain watersheds with narrow elevation bands like the Feather and North Fork Yuba in California, where a 500‐m elevation gain can amount to >50% of the watershed area. Using a ±350‐m ZFL forecast error, we find inflow volume uncertainties of 50% of the flood pool storages at Lake Oroville and New Bullards Bar reservoirs, depending on the ZFL, antecedent moisture condition, and the precipitation event magnitude. The uncertainties can increase by up to >3% per inch (25.4 mm) of precipitation, depending on the ZFL and antecedent moisture condition. This result substantiates the significant impact of ZFL forecast error and the critical need of ZFL forecast accuracy to support reservoir flood control operations in the two watersheds.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 01, 2020
- Source ID
- 10.1029/2020wr027072
Entities
People
- Brian Henn
- Edwin Sumargo
- Forest Cannon
- Fred Ralph
Organizations
- Bakersfield Department of Water Resources
- Scripps Institution of Oceanography
- United States Army Corps of Engineers
- Vulcan Inc.