South Atlantic Water Science Center (SAWSC)
Floods, Droughts, and Hurricanes
A major element of the USGS mission is the documentation of the extent and magnitude of extreme hydrologic events, like floods and droughts. The South Atlantic Water Science Center is a leader in monitoring extreme water conditions, from droughts and falling groundwater levels to floods and storm-tide surges to water-quality problems.
View the South Atlantic WSC topics about floods in Georgia, North Carolina, and South Carolina.
When rainfall is less than normal for several weeks, months, or years, the flow of streams and rivers declines, water levels in lakes and reservoirs fall, and the depth to water in wells increases. If dry weather persists and water-supply problems develop, the dry period can become a drought.
Hurricane Information for Georgia, North Carolina, and South Carolina.
Preventing flood hazards, such as the hurricane induced storm surge, from becoming human disasters requires an understanding of the relative risks floods pose to specific communities and knowledge of the processes by which flood waters rise, converge, and abate. Historically, hurricane-induced storm tides have been documented through measurement of high-water marks left on structures or vegetation. However, these sources are not always reliable or accurate and do not provide quantitative information about the timing of the flooding, the sequencing of multiple paths by which the storm-surge waters arrived, or the magnitude of waves comprising floodwaters.
In response to these deficiencies, the U.S. Geological Survey – South Atlantic Water Science Center, in cooperation with various municipal, State, and Federal cooperators, uses four monitoring approaches for measuring the timing, magnitude, and duration of hurricane storm-surge dynamics. Two approaches utilize a fixed network of gage locations and two approaches utilize the temporary deployment of water-level sensors.
The U.S. Geological Survey (USGS) South Atlantic Water Science Center streamgage program is part of the nationwide program that provides streamflow information for a variety of purposes—including the protection of life and property, infrastructure design, recreational usage, and long-term trend assessment.
The U.S. Geological Survey (USGS) has created flood-inundation maps for selected streamgage sites in North and South Carolina. These maps depict the approximate area that would be inundated at selected water levels, ranging from approximately top-of-bank to a selected maximum water level. The inundated areas depicted on these maps are approximate, and accuracy of the maps is a function of the accuracy of the topographic data and the hydraulic models on which the maps are based.
A critical aspect of the uniqueness of coastal drought is the effects on the salinity dynamics of creeks, rivers, and estuaries. The location of the freshwater–saltwater interface along the coast is an important factor in the ecological and socioeconomic dynamics of coastal communities. Salinity is a critical response variable that integrates hydrologic and coastal dynamics including sea level, tides, winds, precipitation, streamflow, and tropical storms.
Evaluation of the Coastal Salinity Index (CSI) indicates that it provides additional coastal response information as compared to the SPI and the Palmer hydrologic drought index, and the CSI can be used for different estuary types and for comparison of conditions along coastlines.
As Hurricane Matthew moves up the Atlantic coast of the U.S., the USGS South Atlantic Water Science Center (SAWSC) deployed most of the USGS Storm-Tide Network along the Atlantic coast to monitor the timing, extent, and magnitude of the storm tide during the passage of Hurricane Matthew.
• Go to the USGS Hurricane Matthew Information Portal
The multiyear drought in North and South Carolina (summer 1998-fall 2002) brought wide recognition of the vulnerability of the water resources in these two States to climatic conditions. To prepare for drought conditions in the future, water managers and State and Federal water-resource agencies sought to develop tools to assess hydrologic conditions in both a predictive and responsive manner. USGS partnered with the Catawba-Wateree Water Management Group to establish a monitoring network of near real-time streamflow gages (surface-water stage/discharge) and wells (groundwater levels), which are the essential components for assessing hydrologic conditions.
Find out about drought conditions in Georgia. Our page offers links to maps and data, as well as Georgia and National drought links, drought resources from other agencies, and pertinent publications.