CISA: Carolinas Integrated Sciences and Assessments, A NOAA RISA Team

Coastal Salinity Index and Ecological Indicators of Coastal Drought

As part of the Coastal Carolinas DEWS, NIDIS is currently providing funding to the USGS South Atlantic Water Science Center (Paul Conrads) and CISA to advance the development and use of the Coastal Salinity Index (CSI).

The Coastal Salinity Index (CSI)

The Coastal Salinity Index (CSI) was developed as a way to characterize coastal drought. Commonly-used drought indices characterize hydrological, agricultural, and meteorological conditions; however they do not incorporate salinity, which is the primary stressor associated with coastal drought. Paul Conrads developed the CSI using an approach similar to the Standardized Precipitation Index (SPI), substituting total monthly precipitation with average monthly salinity data. The CSI provides a tool to monitor the freshwater-saltwater interface and better understand the effects of changing salinities on fresh and saltwater ecosystems, fish habitat, and freshwater availability for municipal and industrial use. More information about the development of this tool is available in >Conrads and Darby (2016) and on the >USGS SAWSC’s website.

In 2017-2018, Paul Conrads and USGS colleagues will: create a CSI R-package for consistent computation of the CSI by different users, develop a website with access to real-time CSIs, and compute the CSI at additional locations across the Southeast U.S. The CSI has been calculated for 21 sites in South Carolina, Georgia, and South Florida. Contact Paul Conrads ( for more information about the CSI and available calculations.

Indicators and Indices of Drought in Southeastern Coastal Ecosystems

With funding from the NOAA Climate Program Office (2013-2017), CISA initiated this project to improve understanding of coastal resources that are adapted to or dependent upon particular spatial and temporal patterns of salinity. Understanding the relationship between these resources and salinity will inform researchers and managers about the ways in which drought stresses coastal systems. The project was conducted in two phases. First, a needs assessment was completed through structured interviews with 30 resource managers along the Carolinas' coast to identify opportunities for drought early warning and monitoring through the use of a new index, as well as additional data and research needed to effectively understand and monitor drought in coastal ecosystems (>Nolan et al. 2016).

The second component of this project involved collaboration with Paul Conrads at the US Geological Survey South Atlantic Water Science Center (USGS SAWSC) to inform the development of the Coastal Salinity Index (CSI). Activities include 1) synthesizing existing information about salinity and drought effects on coastal resources and 2) identifying and documenting salinity datasets for calculating the CSI and ecological response datasets to assess linkages between ecological variables and salinity levels as expressed by the CSI. Researchers have also begun to investigate the linkages between ecological indicators (for example, blue crab landings, bald cypress growth, and fisheries monitoring data) and varying salinity levels expressed by the CSI.

Next Steps: Testing and Applying the CSI

CISA’s 2017-2018 activities will support research and engagement with CSI users to assess how the CSI can be applied and provide value to drought monitoring and decision making. This will include ongoing work with Coastal Carolinas DEWS partners to identify and obtain environmental response datasets as well as to use those datasets to assess linkages between coastal drought and salinity with affected environmental resources.

The CSI Working Group was established in 2016 to provide feedback on the development of the CSI and recommendations for its use by researchers and resource managers. The USGS-CISA team schedules quarterly webinars with the group. Contact Kirsten Lackstrom ( to find out how you can participate.

Resources and Related Information