S.S. Lee, B.F. Power, and S.T. Cockerham University of California, Riverside

Severe rainfall events are not common occurrences in Riverside, California, where the 25.58 cm mean annual rainfall is distributed November through March with 21.0 cm yr^-1 for the last five drought years. Four major storm sets between October, 2004, and February, 2005, brought 32.54 cm of rain. The largest two brought 10.31 cm over 4–days in January 7-11 and 11.10 cm over 5 days in February 17-23. Damage to the experiment station was highly significant. The capacity of the drain system, designed primarily for irrigation water recovery, was surpassed by the rain runoff causing silting of drain lines field erosion, internal roads to become impassable, and furrows in existing research orchards to sand over. The loss of 16 FTE in the downsizing of 2003 had impacted the maintenance of the drainage system. Persistent rains and increased humidity caused excessive fruit drop and rind rot of navel oranges, and inhibited picking crews access to orchards. Experimental data was lost with washouts in row crop plots. Damage repair was required before spring farming operations could begin. After each storm set, the damage was assessed for impact upon surrounding streets, upon projects, and upon the core facility. The recovery and repair requirements were estimated with a decision as to whether to implement a short-term repair or to take time for a permanent fix. A crew of two was assigned full time to the recovery and repair with priorities set daily for all crews to adjust workloads for response to the assessed damage. Over 500 labor-hours and 200 hours of equipment time were used in response to the problems.