From Drought to Flood – Operational Issues and Challenges of California’S Recent 5-Year Drought
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From Drought to Flood – Operational Issues and Challenges of California’s Recent 5-Year Drought Jonathan Frye , PE, CFM Engineering Manager Santa Barbara County Flood Control District Santa Barbara County FCD FMA Conference – Sept. 2017 1 of 11 The Media - Winter Forecasts NWS clearly qualifies and explains their long term winter outlooks. Winter forecasts often misinterpreted by the media and public agencies Example: NOAA NWS fall 2015 prediction of 50-60% of greater-than- Normal Rainfall vs the NOAA CPC prediction of 90% chance of El Nino. NWS Winter Outlook - Fall 2015 Media Reporting - Fall 2015 Santa Barbara County FCD FMA Conference – Sept. 2017 2 of 11 Forecast Misunderstandings The (2015) 90% chance of El Nino is often assumed synonymous with the ~60% chance of greater than normal rainfall (..but the former is a SST Oceanographic process, as opposed to an Atmospheric process) Although being prepared for significant rain/flooding is good…..the downside of these misunderstandings is a lack of water conservation due to perceived imminent storms - all during a 5 year historic drought. ~70% of Normal Rainfall – Spring 2016 Continued 5-Year Historic CA Drought – May 2016 Santa Barbara County FCD FMA Conference – Sept. 2017 3 of 11 SB County FCD Annual Preparations Each winter Santa Barbara County FCD preparations are typically the same regardless of winter weather outlook predictions Long term winter forecasts are of value, but forecast variability & prudent FCD practices warrant consistent & comprehensive seasonal preparations. Recent case in point is the highly anticipated 2015-16 (El Nino) year that ended drier-than-normal (in SoCal), and the wetter than normal 2016-17 SB County Flood Control Preparations Santa Barbara County FCD FMA Conference – Sept. 2017 4 of 11 Pre-winter Coordination Meetings California Department of Water Resources – Flood Management (Sept. 26, 2017) USACE Twitchell Reservoir Flood Coordination Meeting (Aug 17, 2017) NWS Winter Outlook & Hydrology Coordination (Oct. 3, 2017) USBR Santa Ynez River Flood Modeling Meeting (Oct/Nov 2017) Santa Barbara County FCD Pre-Winter Procedures, Processes, and Safety Coordination. (Sept 2017) COSB-FCD CA-DWR NOAA-NWS USBR USACE Santa Barbara County FCD FMA Conference – Sept. 2017 5 of 11 SB County Burn Area Preparations Large scale burn areas experienced within recent years may require additional flood control preparations for downstream resource protection. (Maintenance, Debris Racks, Gauges, Hydro-mulch) 2016 Burn Areas (Rey Fire, Sherpa Fire) 2017 Burn Areas (Whittier Fire, Alamo Fire) Whittier Burn Area - 2017 Burn Areas x 5 – 2016 & 2017 Santa Barbara County FCD FMA Conference – Sept. 2017 6 of 11 Burn Area Gauge Operations SB County FCD has ~85 automated network gauges. Burn areas are assessed for suitability for a new gauge, or replacement of a recently burned gauge. Gauge installations are coordinated with the USFS Baer team, NWS, and USGS Rainfall intensity alarm notification criteria established for susceptible burn areas. Whittier Fire – replacement of Whittier Fire above Lake Cachuma burned rain gauge Santa Barbara County FCD FMA Conference – Sept. 2017 7 of 11 Lake Cachuma Santa Barbara County’s Largest Water Supply Reservoir (~190k ac.ft.) Capacity low of 7% in 2016 to 51% in 2017 Lake Cachuma (Dec 2016) – 7% Capacity Lake Cachuma (April 2017) – 51% Capacity Santa Barbara County FCD FMA Conference – Sept. 2017 8 of 11 Lake Cachuma Santa Barbara County FCD FMA Conference – Sept. 2017 9 of 11 Lake Cachuma (Time-lapse Video - 2013 to 2017) Santa Barbara County FCD FMA Conference – Sept. 2017 10 of 11 Thank You Jonathan Frye , PE, CFM Engineering Manager Santa Barbara County Flood Control District Santa Barbara County FCD FMA Conference – Sept. 2017 11 of 11.