ABSTRACT
Drought is a naturally recurring climatic feature of most regions of the world that can negatively impact many sectors of society, including agriculture, water resources, energy, ecosystem services, and economic conditions. In the United States, drought has been a common natural hazard, often impacting large regions of the country. Figure 15.1 shows that since the late 1880s, an average of more than 20% of the country has been affected by drought at any given time, including key drought episodes such as the 1930s Dust Bowl and pronounced periods in the 1950s, late 1980s, and 2000s (NCDC, 2013). As a result, drought ranks as one of the most costly natural hazards in the United States, accounting for $6–$8 billion in losses per year (NCDC, 2014). The impact and significance of drought is expected to increase as the climate changes and climatic extremes increase (Dai, 2012), and as demands on finite water supplies continue to increase to support competing sectoral demands (e.g., agricultural, municipal, industrial, and ecological). Percent area of the United States in moderate to severe drought as defined by the Palmer Drought Severity Index (PSDI) for 1985 to 2013 (modified from NDMC, 2014), with the horizontal line demarcating the 20.5% historical average area of the United States under this severity range of drought conditions. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429089435/9c570d80-7548-4c77-8c7f-d7be50eaec81/content/fig15_1.jpg" xmlns:xlink="https://www.w3.org/1999/xlink"/>
