STORMCON 2017 PAPER AHERN_R12

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1 STORMCON 2017 PAPER AHERN_R12 WHAT HAPPENS WHEN STORMWATER DISCHARGERS ARE CAUSING BUT NOT THE SOURCE OF BACTERIA VIOLATIONS Daniel Ahern P.E.,BCEE, National Stormwater Center, Beaufort SC ABSTRACT Problems with the current fecal indicator bacteria have led to the situation where some stormwater discharges are meeting water quality bacteria criteria at the discharge point but are leading to instream violations of the criteria below the discharge point. New stormwater discharges are pushing reservoirs of bacteria from forested wetlands into downstream receiving waters. This leads to the interesting situation where stormwater discharges are the causing but not the source (load) of the bacteria causing the violation. This was not envisioned in the Clean Water Act (CWA) and is different than the normal cause/source assessment. The Environmental Protection Agency (EPA) as part of its responsibilities periodically issues technical guidance and its latest guidance on Recreation Criteria came out in While it still recommended the previous Fecal Indicator Bacteria (FIB) of E. coli and Enterococci, it noted that epidemiological studies seemed to indicate that most illnesses were probably viral and the noted that indicator bacteria were endemic to subtropical and temperate waters. It further stated that studies show proliferation of the indicator bacteria in tropics and subtropics. This paper will try to link the problems with the indicator bacteria with some situations and stress the importance of determining if stormwater discharges are the causing or source of the in-stream violation. This is important in determining how to approach reducing the violation. EPA is considering changing its recreation criteria to include a viral indicator (coliphage) as a better measure of recreational risk. Food and Drug Administration (FDA) that manages the National Shellfish Sanitation Program (NSSP) has utilized coliphage in certain situations and included their use in their 2015 revision to the Guide for the Control of Molluscan Shellfish. EPA s criteria document revision was in the works for 2017 but now the status is uncertain. This paper will report on the expert panel recommendations on this viral indicator and the status of the recreational criteria at the time of the presentation. KEYWORDS Recreational Water Quality Criteria, Fecal Indicator Bacteria, Coliphage, Runoff Volume Control, ASR discharge impacts

2 INTRODUCTION Problems with Fecal Indicator Bacteria(FIB) criteria were initially faced by communities in Beaufort County, South Carolina when certain shellfish harvesting areas were closed in Beaufort County, South Carolina is located in the southeast corner of South Carolina between Charleston, South Carolina and Savannah, Georgia. Due to the coastal location, the county has been an attractive location for resorts and other types of development. Many of the tidal receiving waters in the county are designated as shellfish harvesting waters and, in some cases, outstanding resource waters. Protection of water quality in the county is a priority for its citizens. Because protection of water quality was a priority the County developed additional requirements (above state requirements) in the 1990 s and a stormwater manual that provided guidance regarding the selection and design of best management practices that would meet a goal of pollutant loading characteristic of a low-density development with imperviousness of 10 percent of less. This loading reduction became known as the equivalent impervious cover After another shellfish closure in 2009, the County and the Town of Bluffton investigated possible causes, and the volume of stormwater came under increased scrutiny. Increased stormwater volume from development projects was implicated in salinity changes, increased discharges into wetlands with increases in fecal coliform at wetland outlets, and impacts to fisheries. With direction from County Council, the County and then the Town developed a volume-based criterion based on a 95th percentile storm event (derived from the federal facilities standard in the 2007 Energy Independence and Security Act). This 95th percentile storm event in Beaufort County amounts to 1.95 inches in 24 hours. In developing the stormwater manual to meet this criterion, it was discovered that the equivalent impervious cover concept historically used for water quality control design could be adapted for the new volume control criterion. Of some surprise, however, was that routine monitoring by the County and Town had shown unexpected increases in fecal coliform loads from wetlands and natural drainage systems not receiving stormwater from developments. A unique partnering opportunity presented itself in 2011 to shed light on this issue by testing uniform freshwater discharges during the cycle testing of Beaufort Jasper Water and Sewer Authority s (BJWSA) new Aquifer Storage and Recovery (ASR) system. A monitoring plan was developed with the help of local scientists, to better understand the result of high quality water being rapidly discharged in high volume through a ditched wetland. This study demonstrated the fecal coliform load to the tidal shellfish harvesting areas is dependent upon the volume entering the wetland. Any additional discharge leaving the wetland above which naturally occurs will increase loading, even if the discharge to wetland has no load of its own. As part of their effort to reduce loads to the shellfish harvesting areas from the above watershed, the Town of Bluffton build a detention pond that diverted flow from the creek, reduced bacterial

3 concentration by more than 90 percent, and then saw the in-stream concentration increase back to background levels less than a 1000 feet distance below the pond discharge. PROTECTING WATER USES FROM MICROBIAL ORGANISMS Certain microbial organisms (sometimes referred to as pathogens) can make our waters unsafe for humans. Swimming and other recreational activities in water contaminated with pathogens can make people ill. Consumption of shellfish exposed to waters with pathogens can also make people ill. Both EPA and the FDA through the National Shellfish Sanitation Program (NSSP) have developed criteria to protect the public from these microbial organisms. EPA does this through its requirement under section 304 of the CWA to develop and publish water quality criteria that accurately reflect the latest scientific knowledge on the kind and extent of all identifiable effects on health and welfare that might be expected from the presence of pollutants in any body of water. EPA has published two Recreational Water Quality Criteria (RWQC) documents concerning pathogens since The first was in 1986 and the latest was in This document again recommends using the (FIB) enterococci and E.coli as indicators of fecal contamination for fresh water and enterococci for marine water. The National Shellfish Sanitation Program also develops and publishes criteria through their Guide for the Control of Molluscan Shellfish. Their primary indicator is fecal coliform as their FIB. FIBs are used as criteria because it is not possible to test for all pathogens. Since they are indicators of possible fecal contamination, it is assumed that the absence of indicators also indicates the absence of pathogens. Pathogens can be many types organisms besides bacteria. Researchers in EPA s 2012 criteria document mentioned that many of the illnesses identified in epidemiological studies after recreation water use are thought to be viral. FDA in their 2014 Meeting report noted that fecal coliforms are inadequate for certain enteric viral pathogens because some viral pathogens will remain viable after bacterial indicators indicate safe conditions. The NSSP guide cites studies showing bacteria in seawater surviving from a few hours to five (5) days and longer while viruses can survive in marine water and shellfish from a few days to over 130 days. While the National Shellfish Sanitation Program was initiated after a major Typhoid (bacteria) outbreak in the 1920 s, many of the recent illnesses have been attributed to viruses. The 2012 RWQC document also noted a number of findings from studies that were not widely known. These include for the two recommended FIBs: - naturally occurring environmental sources of FIB, particularly under tropical conditions; - FIB are endemic to tropical, subtropical and temperate regions; - studies that show proliferation of E.coli, enterococci and/or fecal coliforms in tropics and subtropics; - and changing environmental conditions in tidally-influenced sediments help support proliferation and elevated FIB in water.

4 This proliferation (aka growth) could explain some of the load coming out of forested wetlands in Beaufort County SC and the growth on biofilm in the streets of Orange County CA that was described in a June 30, 2010 (Skinner, et al, Regrowth of Enterococci & Fecal Coliform in Biofilm, Stormwater Magazine, July-August, 2010). Both EPA and FDA have been considering an enteric virus risk indicator. The Interstate Shellfish Sanitation Conference (ISSC) held a Male Specific Coliphage (MSC) information meeting in 2014 which lead to its further use in NSSP guide. It is now used in part to assess impacts or raw sewage discharges and determine when areas can be safely opened for shellfish harvesting. The expert panelist consensus from this report included the following: 1. MSC should not be used to replace Fecal Coliform 2. MSC should be used in many situations with fecal coliform to assess and establish harvesting classification zones around waste treatment plants and combined sewer systems. MSC is one of the many viruses labeled as bacteriophage because it infects bacterial cells. This coliphage infects E. coli that have small appendages called pili (these E. coli are referred to as male bacteria). The ISSC meeting report also outlines eight (8) characteristics of an effective indicator: 1. Should be a derived intestinal microflora of warm-blooded animals 2. Should be present whenever pathogens are present 3. Should occur in greater numbers than the pathogen of concern 4. Should be absent or at least very few numbers in clean waters 5. Should be detectable and quantifiable by easy, rapid, inexpensive methods 6. Should be non-pathogenic 7. Should not multiply in the environment 8. Should respond to natural environmental stress and wastewater treatment processes and disinfectant in a manner similar to the pathogen of interest. Unfortunately there appears to be areas of the country where current FIBs do not meet the two italicized characteristics. EPA also conducted a review of coliphages as possible indicators of fecal contamination in 2015 and in March 2016 convened the Coliphage Experts Workshop. This report has not been published at time of this paper but EPA feels that Coliphages are useful for evaluating surface water quality because: 1. Are of fecal origin and present in high number in sewage 2. Are physically similar to viruses causing illnesses associated with primary contact recreation 3. Do not re-grow in surface waters, thus their presence specifically indicates fecal contamination

5 4. Are non-pathogenic 5. Can be counted cheaply, easily and quickly 6. Show correlations to gastrointestinal illness 7. Are similarly resistant to sewage treatment and environmental insults as enteric viruses of concern EPA had been planning to modify its 2012 RWQC to establish a recommended indicator for viruses in surface waters that is protective of human health for primary contact recreation. This would not replace the currently recommended FIB but would allow optional adoption by states. Presently this activity is on hold. The NSSP 2015 guide already established a viral indicator criteria which is a not to exceed level for MSC of fifty (50) male-specific coliphage per 100 grams. This indicator has been used for reopening shellfish harvesting after impacts from raw waste water discharges and treatment plant upsets. It will be interesting to see what criteria EPA will set for primary contact recreation and whether they will use MSC as the NSSP does or adopt some other type of coliphage. There is a definite need to utilize an enteric virus indicator and for research to determine recreation and consumption risks when you have high levels of FIB (due to proliferation) and low MSC levels. Unfortunately there does not seem much interest in studying this situation. The FIB growth issues in certain parts of the country present a challenge to the current vision for assessment, restoration and protection under the CWA. This envisions waters whose uses are impaired by a contaminant (cause) from an either a point or non-point discharge (sources) that is discharging this contaminant. After the assessment of an impairment, restoration would generally be through a recovery plan (called a TMDL) that would require the sources to reduce the discharged contaminant (cause) to levels that would return the use. EPA previously submitted National Water Quality Inventory Reports to Congress and the last one posted on EPA s web site (2004) lists Pathogens as the number one cause of impairments in our rivers and streams. While the currently recommended FIBs have a number of issues, the good news is they are protective except when enteric viruses could be an issue. The use of a coliphage indicator could solve this issue. STORMWATER CONTROLS FOR PROTECTING RECREATIONAL WATER USES Protecting recreational (and shellfish harvesting) uses from stormwater discharges requires the control and/or reduction of the load of contaminants (number of FIBs) that are discharged into a water body. If the load is too great then the recreation criteria (concentration of FIBs) will be exceeded and the water use will be considered impaired. It is important to remember that the load is the concentration of the contaminant times the volume of the discharge. The unique situation that occurs when you have apparent FIB growth/proliferation is that the having a low load of contaminants (number of FIBs) in the stormwater discharge will not necessary reduce the load of FIBs in the downstream receiving waters. This is a case where the

6 stormwater discharge is not a significant source of the FIB discharge load but the impairment would not occur if the discharge was not there. Therefore, the stormwater discharge because it is not the source (load) of the contaminants causing the impairment it will be considered the causing of the impairment. For purposes of this article, when stormwater discharges are not a significant source of the contaminant but are causing the increase in the receiving waters it will be considered causing but not the source. This is a little unusual because cause has generally been what is observed in the assessed water. EPA has recognized hydromodification as the leading source of impairments, but in these cases the hydromodification (ditching) was also the source of the contaminant. In the cases in Beaufort County, the hydromodification (ditching wetlands) had occurred during the time the land was in use as silverculture and it did not lead to impairments. With the apparent regrowth of FIB the source/cause issue is confused. In this situation the increased volume of the stormwater discharge from new development is causing but not the source of the increase in FIB in the receiving waters. Given this potential, it is very important to determine if a stormwater discharge is the source of the FIBs or causing the increase in downstream waters. This knowledge will determine the stormwater controls that must be employed to correct the impairment. Unfortunately with a focus on end of pipe considerations there are many monitoring situations where discharges are only measured at the end of pipe or BMPs have influent and effluent sampling with no consideration of contaminant levels downstream based on the discharge. An example would be road expansions that are not normally considered sources of FIBs, but increased stormwater runoff volume from these road expansions can lead to increased FIBs loads being discharged from downstream wetlands because of regrowth or washout of FIB reservoirs in these forested wetlands. In Beaufort County, SC there was considerable monitoring performed to determine the source of the contaminants both from stormwater discharge points and in-stream locations both above and below discharge points. This monitoring indicated low FIB concentration from stormwater discharges but increased downstream loads impacting downstream water uses. This monitoring data lead to the decision to address the volume side of the load equation rather than the further reduction of the concentration of FIBs. The rigid water quality controls that had been required of stormwater discharges had resulted in very low concentration of FIBs in the stormwater discharges. Since regrowth or wash out of FIB appeared to be quickly occurring in the receiving ditches through forested wetlands, the decision was made to require volume controls to approach predevelopment hydrology as the most cost effective way to decrease the load in downstream waters. The monitoring data was further expanded by a controlled monitoring event (Ahern, et al, Are Wetlands a Problem or Solution for Bacterial Pollution, SCEC 2012 Annual Conference, March 2012). This study presented monitoring data during a controlled three-day discharge from BJWSA s aquifer storage and recovery (ABS) cycle testing. The findings concluded that little flow left the watershed before and after the water authority discharge. Concentrations in wetland areas were high before discharge (1000+CFU/100 ml), increased precipitously shortly after

7 discharge began (20,000+ CFU/100 ml), and then fell below predischarge levels (100+CFU/100 ml) until discharge ceased, at which time concentrations increased back to above background levels (2000+CFU/100 ml). While fecal coliform concentrations after the first flush rapidly decreased, the discharge obviously continued to result in substantial fecal coliform loadings to the shellfish harvesting areas below as long as flow was adequate. While direct comparisons of the wetland concentrations of fecal coliform to the Food and Drug Administration s shellfish harvesting criterion (14/43 Colony Forming Units (CFU)/100 ml) and South Carolina s previous recreational criterion (200/400 CFU/100 ml) are inappropriate, they do serve to put the wetland results into context. Data collected prior to the water authority discharge indicated that there were high background concentrations of fecal coliform within the ditched wetland (most ditches were constructed during previous commercial timber plantations) that, under most conditions, never left the watershed. With the discharge, bacterial loading from the watershed dramatically increased. This reinforced the decision that the only way to decrease loads to the downstream waters was to focus on reduction of the stormwater runoff volume when FIB concentration of the discharges are low and go to forested wetlands. Stormwater dischargers into forested wetlands in warmer climates should not be too quick to assume that they are not part of the problem when their discharges appear to have low concentrations of FIBs in their discharge. Many dischargers assume that because they are not discharging a significant part of the load in the receiving waters that they are not part of the problem. It appears that regrowth and possible resuspension of FIB s from stream/ditch sediments may be overlooked in many efforts to reduce bacterial impairments. Additional instream monitoring could provide much needed data to determining controls needed. Stormwater discharges need to determine whether they are a source and/or causing of the impairment. This will determine whether water quality or water quantity control is the best method of addressing the impairments. If it is determined that the discharge is a significant source of the load to the receiving waters then water quality best management practices (BMPs) that reduce concentration may be the way to help return the impaired water uses. If it is determined that regrowth or other natural reservoir of FIBs may be the issue, then reducing the volume of the stormwater discharge by volume reduction BMPs may be the best way to help restore the impaired water uses. While trying to restore pre development hydrology is a good method of handling stormwater and is in part the basis for low impact development (LID) and green infrastructure (GI) it may also be the best way to approach retrofits when impairments already exist due to regrowth in receiving waters. Stormwater controls for protecting recreational uses must consider whether the stormwater dischargers are the source or causing of a bacterial impairment and determine what is the most cost effective portion of the load equation to reduce (concentration and/or volume). The use of coliphage as a virus indicator may help in determining if human sources are part of the FIB problem and further assist in determining which stormwater controls are needed. The use of coliphage may also be an alternative to consider before doing expensive bacterial source tracking.

8 SUMMARY Criteria measured to protect recreational and shellfish harvesting water uses have some unique situations that impact how stormwater discharges should be handled to protect these uses. Forested wetlands in warmer zones of the country can be major reservoirs of fecal indicator bacteria (FIB) and increased volume from new stormwater discharges can lead to impairments of recreation and shellfish harvesting uses even through discharged FIB loads from the stormwater discharge are low. When this occurs the stormwater dischargers are not the normal source of the problem because they are not discharging significant amounts of the cause (FIBs) but are causing the impairment by the washing out of the FIBs from the wetlands. Controls for stormwater dischargers will depend on what part of the equation of load equals concentration times volume will be most cost effective in reducing loads downstream. When receiving wetlands are major reservoirs or there is suspected regrowth of FIBs, the stormwater volume part the equation may be the only way to restore impaired water uses. The Male Specific Coliphage (MSC) offers a virus risk indicator that can be used in conjunction with FIBs to better determine risk and best stormwater controls to use when trying to protect recreational water uses REFERENCES FDA, National Shellfish Sanitation Program, (2015) Guide for the Control of Molluscan Shellfish ISSC, Interstate Shellfish Sanitation Conference (August 18-19, 2014), Male Specific Coliphage Meeting Report EPA, (2012) Recreational Water Quality Criteria, Office of Water 820-F EPA, (2015), Review of Coliphages as Possible Indicators of Fecal Contamination for Ambient Water Quality, Office of Water 820-R EPA, 2009, Technical Guidance on Implementing the Stormwater Runoff Requirements for Federal Projects under Section 438 of the Energy Independence and Security Act, Office of Water, 841-B Ahern, et al, Are Wetlands a Problem or Solution for Bacterial Pollution, SCEC 2012 Annual Conference, March 2012 Ahern, et al, Integrating Stormwater Runoff Quality and Quality Requirements, Stormwater Magazine, January-February, 2012 Skinner, et al, Regrowth of Enterococci & Fecal Coliform in Biofilm, Stormwater Magazine, July-August, 2010