South Carolina Drought Frequently Asked Question's

Below you will find answers to the most frequently asked questions that we receive. If you don’t see your question, please email us at drought@dnr.sc.gov.

What is the Drought Response Committee (DRC)?
The DRC monitors climatic conditions, evaluates drought indicators, and consults with stakeholders to issue drought status updates for the purpose of managing water resources in the best interests of all South Carolinians. The DRC is made up of five state agencies and 48 local representatives to comprehensively address drought across multiple water using sectors in South Carolina.
Which State Agencies are members of the DRC?
The five state agencies that sit on the DRC are the Department of Natural Resources, Department of Agriculture, Department of Health and Environmental Control (DHEC), State Forestry Commission, and Emergency Management Division. The DRC is chaired and supported by the Department of Natural Resources (SC DNR) and the SC State Climatology Office (SC SCO).
Who serves as the local members?
There are 48 local members that sit on the DRC. There are 12 local groups to make sure water is available for multiple sectoral needs. All these groups are represented in each of the four Drought Management Areas. The 12 groups are agriculture, commission of public works, counties, domestic user, industry, municipalities, power generation facilities, private water supplier, public service district, regional council of governments, soil and water conservation districts, and special purpose districts. The description of each can be found here.
What are the Drought Management Areas (DMAs)?
The DMAs are based on the four major river basins of the State: The Savannah, the ACE, the Santee, and the Pee Dee. Typically, the DMAs are referred to by their geographic location rather than their corresponding river basin. The Savannah is the West DMA, the ACE is the Southern DMA, the Santee is the Central DMA, and the Pee Dee is the Northeastern DMA. Since the DRC makes drought status decisions at a county-level, the DMAs follow county boundaries. The DMAs were delineated using the river basins so that upstream and downstream problems can be considered in the DRC process, while keeping drought status decisions at a county level. Counties were used for drought status decisions as the public generally thinks in terms of political boundaries rather than natural boundaries, such as watersheds or water basins.
Beyond the DMAs, how does location affect the local members?
To make sure that one or a few population centers do not dominate a DMA, a county can only have two members serve in a DMA. For example, there can only be two representatives from Richland County in the Central DMA. This rule stands regardless of the number of vacant DRC in a Drought Management Area. Furthermore, a member represents the county that he or she lives in, not the county that they work in. The purpose of this rule is to make sure that all DRC members are South Carolina Citizens instead of citizens of another state that are employed in South Carolina.
When does the DRC meet?
The DRC meets as needed when conditions warrant discussion. Depending on conditions, sometimes it can be six months between meetings, other times it can be every four to six weeks. During times of severe or extreme drought, meeting become increasingly frequent to make sure that county-level drought declarations and management decisions are keeping up with drought conditions.
What happens when the DRC meets?
When the DRC meets, seven different drought indicators are used to determined conditions across the state. Each of these indicators are discussed, along with state and local condition reports that are brought forward. After evaluating the data and any state and local reports, the DRC goes through each DMA and votes on the appropriate drought status for each county. Local members can only vote on the drought status for counties inside their DMA.
What indicators are used to determine drought severity?
The DRC uses seven different indicators to determine drought severity in South Carolina. These are Precipitation, Crop Moisture Index, Palmer Drought Severity Index, streamflow levels, lake and reservoir levels, groundwater levels, the Keetch-Byrum Drought Index, and the U.S. Drought Monitor. The use of these seven indicators is to take a comprehensive approach to drought monitoring, evaluating climatic, soil moisture, hydrologic, and potential fire conditions. More in depth information about each of these indicators can be found here.
What are the drought designations used by the DRC?
The DRC can designate counties into five different categories: normal, incipient, moderate, severe, and extreme. During meetings, counties are only changed by category (such as from incipient to moderate, and vice versa) if conditions warrant a change.
When does the DRC recommend water curtailment?
During severe or extreme drought, the DRC determines nonessential water use and issues declaration for water curtailment. If curtailment of nonessential water use is not enough to protect water resources during a severe or extreme drought, the DRC can make recommendations to the Governor for further water conservation, enacted with executive power.

Why is it important to serve?
South Carolina is unique as drought declarations are made through collaboration between state agencies and local members. Most states only make state-level drought decision from state agency input. South Carolina’s approach allows local and sectoral input to drive the process for making county-level drought declarations. This is crucial since county-level drought declarations can lead to non-essential water restrictions at severe and extreme drought stages. Serving on this committee provides the unique opportunity for state agencies and local members to collaborate to make sure that water resources in the state are protected and available, while also making sure that any water conservation declarations are not premature, leading to unnecessary impact to public water suppliers in the state.
What are the responsibilities of becoming a committee member?
Committee members are responsible for attending all meetings and contributing to the discussion about conditions. Members should discuss conditions in the county they represent. Members should also discuss conditions from the sectoral group they represent (e.g. agriculture or special purpose districts). When conditions in a basin are deteriorating, it is encouraged that a member talks to other constituents of their sectoral group type within different parts of their respective DMA. This helps to provide better spatial coverage of what conditions are for each sectoral group through out each DMA.

During each DRC meeting, SC DNR and the SC SCO will present the data of the drought indicators used. Other state agencies and the local members are also given time to discuss conditions from their perspectives. Then, going through each of the four DMAs, each county is discussed for what status it should be in (normal, incipient, moderate, severe, or extreme). After discussion, the members of within each DMA and the five state agency members vote on the status for each county within that DMA. Once agreed, the discussion and vote move to the next DMA. This process is complete once the DRC has declared the status of each county.

When one or multiple counties are determined to be in either moderate, severe, or extreme drought, the committee members will decide what non-essential water uses should be recommended for implementation of water curtailment for public water suppliers. This part of the process is typically more common for severe or extreme drought declarations and less common for moderate drought declarations.
What is the process of becoming a committee member?
Are you interested in becoming a Drought Response Committee (DRC) member? If so, please reach out to the SC SCO by email (drought@dnr.sc.gov). We will set up a meeting with you to discuss the process of the DRC and assess what group you or someone from your organization would represent. If it is appropriate for you or your organization to serve on the DRC, we will send your information to the Governor’s Office. An official application will arrive from the Governor’s Office to join the DRC. After submitting and reviewing your application, there will be a background check. Once the final approval is granted, you will receive appointment letters from the Governor’s Office indicating you are a DRC member.
What are the term lengths?
Local members of the DRC are appointed for three-year terms. There is no limit to how many terms a member can serve.

What is the U.S. Drought Monitor (USDM)?
The USDM is a national map that depicts drought severity and extent across the entire Country. It is a blended drought index that uses multiple data types to capture and depict all types of drought (such as meteorological, agricultural, hydrological, socioeconomic, and ecological). This means that while it is easy to see where drought exists in the United States and how severe it is, it may be difficult to understand why the USDM depicting drought conditions.
Who Creates the USDM?
There are multiple USDM authors, all of which belong to one of three agencies: the National Drought Mitigation Center (NDMC), the National Oceanic and Atmospheric Administration (NOAA), and the U.S. Department of Agriculture (USDA). Each map is created by one USDM author, as authorship usually changes every one to two weeks.
What is the USDM Process?
Each week one of the authors updates the map, based on changes to the data. Since the USDM is a blended index, it looks at multiple data types. Along with the data, the USDM also incorporates input from local experts around the country to put the context to the data for any needed changes to the map. This use of input from local experts is a unique feature of the USDM.

Typically, the author starts to look at data on Monday, taking in recommendations from local experts and making changes as information comes in. During this process, the authors send out multiple drafts with changes so local experts and USDM contributors can suggest further changes. Recommended changes to the map are taken until noon on Wednesdays. Thursday morning is when the final map is released to the public.
What data are used for the USDM?
Multiple types of data are used as inputs for the USDM as the map depicts multiple types of drought. The data includes precipitation, soil moisture, vegetation health, temperature, streamflows, groundwater, evapotranspiration, and impact and condition reports. With each location being unique in terms of expected precipitation, soil composition and water holding capacity, and surface and groundwater availability, data used in the USDM is in the form of percentiles. This allows each data point to be ranked from 1 to 100 (1 being the driest and 100 being the wettest), which provide insight to how the current data compares to the historical past for a given location.
What are the USDM drought categories and how do they work?
The USDM has six categories. Two are non-drought categories: normal and abnormally dry (D0), and four are drought categories: moderate (D1), severe (D2), extreme (D3), and exceptional (D4). Since there are multiple types of data that are used in the drought monitor, a convergence of evidence approach is used to determine a location’s USDM category. This means that one data type or one indicator cannot drive the process. Rather, multiple data points and types of data need to show similar conditions to get a specific drought designation. Generally, a higher number of indicators need to converge for more severe USDM category designations.

The six categories of the USDM are based on percentile ranges. Normal is anything above the 30th percentile. Abnormally dry (D0) is the 21st-30th percentile range, moderate drought (D1) is the 11th-20th percentile range, severe drought (D2) is the 6th-10th percentile range, extreme drought (D3) is the 3rd-5th percentile range, and exceptional drought (D4) is the 1st-2nd percentile range. As an example, a D4 designation on the USDM in a location that is experiencing either the driest or second driest conditions on record across multiple data types and indicators.

It takes time for a location to change from one USDM category to the next as it takes time for data to change in the percentile rankings. It also takes time for multiple types of data to change in the percentile rankings. For these reasons, and because the map is updated weekly, a location can only change by one USDM category each week. Also, because of the nature of drought, it is unlikely that drought category will degrade or fluctuate for consecutive weeks.
For more information about the USDM as a national drought product, please visit
https://droughtmonitor.unl.edu/
How does South Carolina participate in the USDM process?
Drought monitoring in the state is the responsibility of the SC SCO, and thus participates in the USDM process every week. Since drought affects multiple sectors, the SC SCO collaborates with multiple state and federal partners within South Carolina to provide recommendations to the USDM. These partners include the S.C. Department of Agriculture (SCDA), Clemson Extension, SC DNR Hydrology, the National Weather Service (NWS), the Farm Service Agency (FSA) and the Natural Resources Conservation Service (NRCS) (both within the U.S. Department of Agriculture), and U.S. Geological Survey (USGS).

Since South Carolina shares river basins with both of our neighbors, North Carolina and Georgia, the SC SCO communicates weekly with their respective USDM collaborators so that conditions match up across state lines, as drought rarely follows political borders.

After collaborating with our partners within South Carolina and discussing conditions with our neighbors, the SC SCO sends the state’s recommendations to the USDM author. The SC SCO typically sends recommendations to the USDM author on Tuesday afternoons. This process of multi-partner and multi-state collaboration is conducted every week.

It is important to note that while USDM is collaborative process with local input, the USDM author always gets the final decision on what the map will depict each week. Therefore, while the SC SCO provides input, the USDM author can reject those changes if he or she feels differently. While this occurrence is seldom, it has happened before and is a possibility in the future.

Why can the DRC map and the USDM map look different from one another?
One question that the SC SCO frequently receives is why the DRC and USDM maps look different from one another. There are three main reason: First, the maps use different data and drought indicators for drought designations. Second, the DRC makes county-level drought declarations, where as the USDM category spatial coverage is based on where different data and indicators overlap, not on political borders. Last, the maps are updated at different time frames, resulting in more frequent changes to the USDM map than the DRC Map.
Want to compare the DRC and USDM processes? Use the table below.
Drought Monitoring and Response Activites in South Carolina