Multi-Hazard Mitigation Plan: 14. Droughts

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Chapter 14:Hazard Analysis—Droughts developing stages. To complicate matters, global warming climate changes due to increasing atmospheric concentrations of carbon dioxide and other radiation-absorbing gases may change the frequency, intensity, duration, and pattern of droughts. 14.1.3 Impacts of Drought Droughts diminish drinking water supplies, cause agricultural losses, and increase the incidence of wildfires. This island is particularly vulnerable to droughts due to pervasive water catchment systems, reliance on diversified agriculture, and expansive pasture and woodland areas susceptible to wildfires. 14.2 Significant Historic Events Droughts have affected the Hawaiian Islands throughout its history. Farmers, cattle ranchers, and individuals who rely on catchment water systems and surface stream diversions are the communities most immediately affected by drought. Areas susceptible to wildland fires are more vulnerable during very dry conditions, and incidences of wildland fire have increased considerably throughout the State. Droughts have impacted almost every island in Hawaii with the most severe events occurring in the past 15 years associated with the El Nino phenomenon. During the El Nino years, droughts occurred during the winter-spring period. For example, in January 1998, the National Weather Service's network of 73 rain gauges throughout the State did not record a single above-normal rainfall, with 36 gages recording less than 25 percent (%) of the norm (NWS Honolulu Forecast Office). The 0.14 inches of rain recorded for the city of Hilo is the lowest monthly total ever observed for any month since records have been kept. Normal January average rainfall for Hilo is 9.88 inches. Parts of the island of Hawaii continued to receive less than 10% of the normal rainfall until May 1998. Drought conditions will continue to affect Hawaii's environment, but the extent of drought and the respective consequences will probably increase in severity. Severe drought conditions may result in crisis-level shortages in water supplies for human consumption, agricultural irrigation, and fire suppression for severe wildland fire hazards. Crop damage and cattle losses have been major concerns during periods of severe drought, resulting in the implementation of both voluntary and mandatory water- conservation measures. The most recent drought of 1998 to 2003 has wreaked havoc on the farmers and ranchers of Hawaii, especially those on the southeastern end of the State. Ranchers are grass farmers whose cattle suffer from decreased grazing areas during drought conditions. The recent drought left the State of Hawaii with reduced cattle carrying capacity, lower calf production, and lower weaning weights, resulting in an enormous loss of revenue. The consequences of this economic impact are compounded by the additional costs to ranchers for supplemental feed and minerals required to sustain the animals during these periods. The economic impacts of drought on Hawaii's cattle industry (i.e., estimated drought-related loss) for 1999 and 2000 have been evaluated. increased cattle mortality and reduced calving rates led to a direct loss in the total number of marketable cattle. The average live weight for 14-3 Hawaii County Multi-Hazard Mitigation Plan