South Carolina 2012 Beachwater Quality Summary
Reported Sources of Beachwater Contamination
(number of closing/advisory days)
- 7 (64%) unknown contamination sources
- 3 (27%) stormwater runoff
- 1 (9%) other, unspecified contamination sources
There are 63 beaches in South Carolina lining 180 miles of Atlantic coastline—102 miles on the mainland coast and 78 miles on islands without bridges from the mainland's barrier islands or on sandbars. The state's beachwater quality monitoring program is administered by the Department of Health and Environmental Control (DHEC).
What Are the Water Quality Challenges and Improvements in South Carolina?
Using Deep Ocean Outfalls to Protect Swimmers in the Grand Strand
The Grand Strand is a stretch of beaches between Little River and and Georgetown. Some of the Grand Strand communities have constructed stormwater outfalls that discharge further out in the ocean instead of at the coast in order to limit beach erosion and reduce localized pollution concentrations for swimmers. These projects, which cost millions of dollars per ocean outfall, have created significant reductions in the amount of fecal indicator bacteria found in beachwater where they have been implemented (7th Avenue South in North Myrtle Beach and Deep Head Swash in Myrtle Beach). In 2011, Myrtle Beach completed construction of the latest ocean outfall, located at 4th Avenue North. This project combined nine existing stormwater drainage pipes that used to discharge at the beach into one pipe that runs underneath the seabed and discharges into the Atlantic Ocean more than 1,000 feet from shore.
NRDC encourages coastal communities to explore solutions that prevent stormwater runoff before it occurs. The high cost of deep-ocean outfalls as a solution to beach erosion and beachwater quality problems illustrates the importance of reducing stormwater runoff by implementing green infrastructure wherever possible. In addition to improving beachwater quality, green infrastructure does not transfer pollution to the ocean and has significant other benefits.
What Does Beachwater Monitoring Show?
In 2012, South Carolina reported 63 coastal beaches. Of these, 1 (2%) was monitored more than once a week, 6 (10%) were assigned a monitoring frequency of once a week, 16 (25%) every other week, and 40 (63%) were not assigned a monitoring frequency. In 2012, 11% of all reported beach monitoring samples exceeded the state's daily maximum bacterial standard of 104 colonies/100 ml. The beaches with the highest percent exceedance rates of the daily maximum standard in 2012 were Myrtle Beach State Park and Campgrounds (20%), Surfside Beach (19%), Myrtle Beach (17%), and North Myrtle Beach (11%), all in Horry County. Horry County had the highest exceedance rate of the daily maximum standard in 2012 (15%), followed by Beaufort (6%), Colleton (2%), and Georgetown (1%). No samples taken at beaches in Charleston County exceeded the standard. NRDC considers all reported samples individually (without averaging) when calculating the percent exceedance rates in this analysis. This includes duplicate samples and samples taken outside the official beach season, if any.
South Carolina Percent of Samples Exceeding the State's Daily Maximum Bacterial Standard for 22 Beaches Reported 2008-2012*
* Please note that only samples from a common set of beaches monitored each year from 2008-2012 are included in the bar chart.
What Are South Carolina's Sampling Practices?
The monitoring season in South Carolina runs from May 15 to October 15. The DHEC determines monitoring locations, sampling practices, standards, and notification protocols, which are uniform throughout the state. Samples are taken in water that is 20 to 40 inches deep, 12 inches below the surface. A sanitary survey (a systematic investigation used to identify potential sources of human sewage pollution) is conducted every time a beach is sampled. In South Carolina, beaches are prioritized for inclusion in the monitoring program on the basis of level of use, water quality history, and other applicable factors. Most of the highest-priority (Tier 1) beaches have stormwater outfalls.
Sampling is deliberately conducted at swashes and outfalls, where water quality is expected to be poorest. Portions of beaches whose water quality has fallen below the standard are sampled daily. States that monitor more frequently after an exceedance is found will tend to have higher percent exceedance rates and lower total advisory days than they would if their sampling frequency did not increase after an exceedance was found.
In addition to the DHEC monitoring, the city of Myrtle Beach uses Coastal Carolina University to conduct year-round sampling at monitoring sites in the city. Thus, during the state's monitoring season, these sites are monitored twice a week. Also, during the monitoring season, the county park on Isle of Palms samples twice per month in addition to the DHEC's twice-a-month monitoring schedule, so water at this beach, which has 9 sampling stations, is monitored four times per month.
How Many Beach Closings and Advisories Were Issued in 2012?
Total closing/advisory days for 9 events lasting six consecutive weeks or less increased 10% to 11 days in 2012 from 10 days in 2011. For prior years, there were 4 days in 2010, 48 days in 2009, and 36 days in 2008. In addition, there were no extended or permanent events in 2012. Extended events are those in effect more than six weeks but not more than 13 consecutive weeks; permanent events are in effect for more than 13 consecutive weeks. For the 9 events lasting six consecutive weeks or less, 100% (11) of closing/advisory days in 2012 were due to monitoring that revealed elevated bacteria levels.
How Does South Carolina Determine When to Warn Visitors About Swimming?
The beachwater quality monitoring program has the authority to issue advisories but not closings; in South Carolina, only elected officials can close a beach. South Carolina applies a single-sample maximum standard for enterococcus of 104 cfu/100 ml. No geometric mean standard is applied when determining whether to issue a beach advisory.
The DHEC issues an advisory immediately when the enterococcus bacteria level is 500 cfu/100 ml or higher. If the bacteria level is above 104 cfu/100 ml but below 500 cfu/100 ml, an additional sample is collected. If the second sample is also above 104 cfu/100 ml, the department issues an advisory. The advisory remains in place until samples show bacteria levels below the state standard. Advisories include the area of the beach that is within 200 feet on either side of the monitoring station where the exceedance occurred. Advisories are posted via signs at the beach, online, and through a Twitter feed.
Most pipe outfalls and swashes in Horry County are under permanent rainfall advisory, with permanent signs advising the public against swimming in the area of the stormwater outfall. This type of standing advisory is not reported to EPA and is not included in NRDC's analysis.
South Carolina 2012 Monitoring Results and Closing/Advisory Days