Drought and Floods

Climate model forecasts indicate an increase in extreme hydrologic events, including floods and droughts, for California and the western U.S. in the future. To better understand what the consequences of this future change in climate may be, USGS scientists are studying the frequency, magnitude, and impacts of past hydroclimate variability and extremes in the region. This project produces well...

The Southeastern U.S. experiences recurring hydrologic droughts, which can reduce water availability for human consumption and ecosystem services, leading to plant stress and reduced plant growth. This project examines relationships between drought and the water cycle in the Southeast with data from the Panola Mountain Research Watershed (PMRW) near Atlanta, Georgia and other Southeastern sites...

Land cover and land use (LC/LU), climate, and biogeochemical processing are significant drivers of water quality in streams and rivers over broad scales of space and time. As LC/LU and climate continue to change we can expect changes in water quality. This project seeks to understand the drivers of spatial and temporal variability in water quality across scales using new and existing data to...

Stream transport (lateral transfer) of carbon remains a poorly understood flux within the global carbon budget. This research addresses the need to refine our knowledge of both provenance and transformations of Dissolved Organic Matter (DOM) as it moves from mountains to sea. Interpreting shifts in carbon quality with increasing stream order, and how these patterns change with variation in...

Climate-related forest disturbances, particularly drought-induced tree mortality and large, high-severity fires from increasingly warm and dry conditions, are altering forest ecosystems and the ecosystem services society depends on (e.g., water supplies). Our research combines long-term place-based ecological data, diverse methods (e.g., paleo, remote-sensing), and networking approaches to...

Forests provide society with economically important and often irreplaceable goods and services, such as wood products, carbon sequestration, clean water, biodiversity, and recreational opportunities. Yet hotter droughts (droughts in which unusually high temperatures exacerbate the effects of low precipitation) are projected to increase in frequency and intensity in coming decades, potentially...

Changes in rainfall patterns as a result of anthropogenic climate change are already having large ecological and socioeconomic impacts across the globe. Increases in flood damage, wildfire damage, and agricultural losses can all be attributed to anomalous rainfall events and prolonged droughts across the United States in recent years. Additionally, Atlantic Ocean circulation, which has a large...

Improper land use during drought has been a major driver of land degradation in drylands globally, especially in the western U.S. Increasing aridity in western U.S. drylands under future climates will exacerbate risks associated with drought and land use decisions. This project provides critical observational, experimental, and modelling evidence to support our DOI partners with decision processes...

The Prairie Pothole Region (PPR) of North America is one of the most important breeding areas for continental waterfowl populations, a Department of Interior (DOI) trust resource. Land use and climate both influence the functioning of the region’s wetland ecosystems, with effects not just on the waterfowl that depend on these wetlands, but also on the services they provide to society, such as...

Extreme low streamflows impact water availability for human systems and ecosystems. Numerous researchers have analyzed trends in low streamflows in the U.S. There is no known published work, however, on historical trends over time in the most extreme low streamflows—the flows with the largest impacts on human systems and ecosystems. The current study attempts to fill this gap. The wealth of...

Previous work performed as part of the USGS Holocene Synthesis project illuminated complex centennial-scale patterns of drought and wetter-than-average conditions across the North American continent interior during the past two millennia, where paleorecord data coverage is sparse. In order to explain the patterns of naturally-occurring drought, floods, and storms for the past, identified by the...

More than a third of the United States population lives in counties directly on the shoreline, making them vulnerable to hazards associated with changing sea level and storm surges associated with hurricanes and severe storms. The geologic record contains many examples of past intervals of warm climate and high sea level. "Geological Investigation of the Neogene" is examining proxy records of...