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HomeMy WebLinkAboutChapter 7 Stormwater and Wastewater Management 59 Chapter 7 Stormwater and Wastewater Management for Improved Water Quality 7.1 Introduction to Stormwater Runoff Stormwater runoff is rainfall or snowmelt that runs off the ground or impervious surfaces (e.g., buildings, roads, parking lots, etc.). In some cases, it drains directly into streams, rivers, lakes, and oceans. In other cases, particularly in urbanized areas, stormwater drains into streets and manmade drainage systems consisting of inlets and underground pipes, commonly referred to as a storm sewer system. Storm sewer systems are designed simply to capture the stormwater and convey it to the nearest surface water without treatment. These sewers should not be confused with sanitary sewers, which transport human and industrial wastewater to a treatment plant before discharging into surface waters. Common stormwater pollutants include sediment, nutrients, organic matter, bacteria, oil and grease, and toxic substances (e.g., metals, pesticides, herbicides, hydrocarbons). Stormwater can also impact the temperature of a surface waterbody, which can affect the water’s ability to support certain fish and aquatic communities. Uncontrolled stormwater runoff has many impacts on both humans and the environment. Cumulative effects include flooding, undercut and eroding streambanks, widened stream channels, threats to public health and safety, impaired recreational use, and increased costs for drinking and wastewater treatment. For more information on stormwater runoff, visit the DWQ Stormwater Permitting Unit at http://h2o.enr.state.nc.us/su/stormwater.html or Chapter 5 of the Supplemental Guide to North Carolina's Basinwide Planning: Support Document for Basinwide Water Quality Plans http://www.ncwaterquality.org/basinwide/SupplementalGuide.htm. 7.2 Stormwater Programs The goal of the DWQ stormwater discharge permitting regulations and programs is to prevent pollution from entering the waters of the state via stormwater runoff. These programs try to accomplish this goal by controlling the source(s) of pollutants. These programs include National Pollutant Discharge Elimination System (NPDES) Phase I and II regulations, HQW/ORW stormwater requirements, and requirements associated with the Water Supply Watershed Program. Currently, there are 23 individual stormwater permits listed for the Chowan River basin and Phase I regulations are not applicable. However. there are a few local governments and/or counties that are affected by other water quality protection programs. DWQ’s Stormwater Permitting Unit webpage: http://h2o.enr.state.nc.us/su/index.htm provides links to the stormwater BMP manual, a map tool to identify where file a permit and guidance on North Carolina’s evolving stormwater programs. A description of Federal and State stormwater regulations and programs are also described in detail in Chapter 5 of the Supplemental Guide to North Carolina's Basinwide Planning: Support Document for Basinwide Water Quality Plans http://h2o.enr.state.nc.us/basinwide/SupplementalGuide.htm. 60 Stormwater and Wastewater Management Stormwater Regulation Challenges One challenge in meeting the goal of enhancing and protecting water quality is the State’s inaccurate or lack of location data to identify permitted stormwater discharges. This permit data is important to DWQ for both tracking and renewing permits, assessing the program, and determining potential cumulative impacts. Discharge outfall locations are also important to compliment protection and restoration efforts by other organizations. To correct this problem, updating discharge locations began in 2005 to include GPS coordinates of outfalls and digital photographs. A temporary administrative staff position has been requested to begin updating or correcting coastal stormwater permit data in DWQ’s Basinwide Information Management System (BIMS) database. DWQ is working with regional offices to ensure data entry is consistent and that protocol exists for collecting GPS coordinates in a consistent manner at permitted sites. There were 15 untreated stormwater outfalls detected in Edenton as a result of the 2005-2006 municipal outfalls survey. 2007 Recommendations DWQ recommends that local government and county officials in the basin develop stormwater management programs for new development and to retrofit existing development. In particular, Chowan County and Edenton would improve water quality in their jurisdiction if they were to voluntarily begin developing stormwater programs with Phase II standards. DWQ and other NCDENR agencies will continue to provide information on funding sources and technical assistance to support local government and county stormwater program development. 7.3 Wastewater Management Programs 7.3.1 NPDES Wastewater Discharge Permit Summary Discharges that enter surface waters through a pipe, ditch or other well-defined point of discharge are broadly referred to as 'point sources'. Wastewater point source discharges include municipal (city and county) and industrial wastewater treatment plants and small domestic wastewater treatment systems serving schools, commercial offices, residential subdivisions and individual homes. Stormwater point source discharges include stormwater collection systems for municipalities and stormwater discharges associated with certain industrial activities. Point source dischargers in North Carolina must apply for and obtain a NPDES permit. Discharge permits are issued under the NPDES program, which is delegated to DWQ by the Environmental Protection Agency (EPA). Currently, there are 10 permitted wastewater dischargers in the Chowan River basin. Table 13 provides summary information (by type and subbasin) about the discharges. The types of dischargers listed in the table are described in the inset box. Facilities are mapped in each subbasin chapter, and a complete listing of permitted facilities is included in Appendix III. Stormwater and Wastewater Management 61 Table 13 NPDES Dischargers and Permitted Flows for the Chowan River Basin (August 2006). Facility Categories 03-01-01 03-01-02 03-01-03 03-01-04 TOTAL Total Facilities 5 0 2 3 10 Total Permitted Flow (MGD) 44,000 0 1,524,000 20,000 1,588,000 Facilities Grouped by Size Major Discharges 0 0 1 0 1 Permitted Flow (MGD) 0 0 1,500,000 0 1,500,000 Minor Discharges 5 0 1 3 9 Permitted Flow (MGD) 44,000 0 24,000 20,000 88,000 Facilities Grouped by Type 100% Domestic Waste 4 0 0 0 4 Permitted Flow (MGD) 2,000 0 0 0 2,000 Municipal Facilities 0 0 0 0 0 Permitted Flow (MGD) 0 0 0 0 0 Nonmunicipal Facilities 1 0 2 3 0 Permitted Flow (MGD) 24,000 0 1,524,000 20,000 1,568,000 7.3.2 Permitted Non-Discharge Waste Management Strategies Due to the nutrient sensitivity of the waters in the Chowan River basin and the strict effluent limits on discharges, non-discharge wastewater treatment systems are more common. The Land Application Unit (LAU) in the Aquifer Protection Section of DWQ oversees non-discharge wastewater treatment and recycle systems including land application of wastewater and residuals. The program has operational and monitoring requirements similar to those of the NPDES wastewater program; however, the primary difference is that the treated effluent is not discharged to surface waters. Instead, it is usually discharged to a spray irrigation system for land application. Some other options for the land application of effluent include rapid infiltration basins and drip irrigation systems. Systems that are reviewed and permitted by LAU include spray irrigation systems, animal waste management systems, rapid infiltration basins, drip irrigation systems, land application of residuals, wastewater collection systems, and beneficial reuse of wastewater effluent. The non- discharge program and all associated permits, is regulated by North Carolina General Statutes 143.215.1 and Administrative Code Section 15A NCAC 2T .0100 - Waste Not Discharged to Surface Waters. These sections not only give DWQ the authority to issue permits; they also provide details on the permitting process and information that must be submitted with a permit application. Every wastewater treatment facility in the State of North Carolina, including large NPDES facilities, pretreatment systems and non-discharge systems, produce some form and amount of wastewater residuals. DWQ requires a permit for the land application of these residuals. The program was developed around the EPA rules 40 CFR Part 257 and 40 CFR Part 503. These treatment systems are designed to satisfy at least the minimum permitting requirements for protection of the surface and ground waters that they could potentially impact. The new rules for waste not discharged to surface waters can be found at: http://h2o.enr.state.nc.us/admin/rules/documents/2Tbook.pdf as 15A NCAC 02T. Numerous non-discharge systems and necessary treatment requirements are described at this website. These rules replaced the earlier 15A NCAC 02H .0200 rule version. 62 Stormwater and Wastewater Management Setbacks are required for all irrigation sites near for surface waters, drainage ditches and waterways. The land surface provides a final "treatment" phase in the disposal process, allowing for uptake and often vegetative removal of nutrients and/or fecal coliform bacteria that may be present in plant effluent depending on the level of treatment permitted for a given facility. However, the effectiveness of this treatment depends upon the ability of the cover crops to take up the nutrients. In additional, the coarse grain sands do not always provide adequate adsorption, and the retention time before it enters groundwater is minimal so soil bacteria do not provide much treatment. With the promulgation of the Subchapter 02T rules, high-rate systems must meet more stringent effluent limitations and/or increased setbacks. Within the Chowan basin, it is important to note that there is a direct connection between groundwater and surface water in many places. Non-discharge systems work well when the site is conducive to infiltration. However, problems can arise when the site is a low-lying area with a high groundwater table (thereby inhibiting infiltration), or with nearby wetlands or ditches that can act as a ready conduit for runoff. Most non-discharge spray irrigation sites have storage ponds that would allow the wastewater to be held until appropriate to spray. If the water table is high in a disposal area, water level meters are installed to prevent irrigation until there is a certain vertical separation between the land surface and the water table. Runoff is a real concern at any irrigation site, but it can be prevented with proper hydraulic loading (water balance), buffering, and storage. It is recommended that research be conducted to better establish and understand the relationship between groundwater and surface water in eastern North Carolina. Such understanding would provide for more accurate assessment of surface water impairments resulting from groundwater discharges and enable the state to make sound permitting judgments and recommendations to better protect water quality in general. Many non-discharge systems are constructed by the developer and turned over to a homeowners association (HOA) after completion. If there is a major problem, the HOA is responsible for the repair bill and funding the repair can be an issue. For systems that will be or are owned by a HOA, the statutes and rules require special accounts be set up by the HOA for the operation of the treatment system. In addition, the HOA must set up a reserve fund for major repairs. Non-discharge systems create some challenges for the DWQ regional offices in terms of inspections and assuring permit and compliance conditions are met. DWQ may seek additional staffing resources to meet these challenges. One of DWQs goals is to better review covenants and bylaws upon permit review to make sure that HOAs are adhering to the financial assuredness requirements under the permit. In the Chowan River basin, 21 non-discharge permits have been issued (Table 14). More information about non-discharge permits can be found on the DWQ LAU Web site (http://h2o.enr.state.nc.us/lau/main.html) and in the Supplemental Guide to North Carolina’s Basinwide Planning document (http://www.ncwaterquality.org/basinwide/SupplementalGuide.htm). Stormwater and Wastewater Management 63 Table 14 NPDES Non-Dischargers and Permitted Flows for the Chowan River Basin. Facility Categories 03-01-01 03-01-02 03-01-03 03-01-04 TOTAL Total Facilities 10 8 0 3 21 Total Permitted Flow (MGD) 1,413,692 1,583,204 0 1,176,040 4,172,936 Facilities Grouped by Size Major Discharges 7 8 0 3 18 Permitted Flow (MGD) 1,409,192 1,583,204 0 1,176,040 4,186,436 Minor Discharges 3 0 0 0 3 Permitted Flow (MGD) 4,500 0 0 0 4,500 Facilities Grouped by Type Government-Municipal 3 6 0 1 10 Permitted Flow (MGD) 1,242,000 1,568,204 0 1,076,000 3,886,204 Government-County 2 0 0 0 2 Permitted Flow (MGD) 29,500 0 0 0 29,500 Government-State 1 0 0 0 1 Permitted Flow (MGD) 25,000 0 0 0 25,000 Non-Government 4 2 0 2 8 Permitted Flow (MGD) 117,192 15,000 0 100,040 232,232 7.3.3 On-Site Waste Management North Carolina has enacted laws and adopted rules that mandate significant requirements for inspection and review of On-site Waste System (OSWS) performance. Siting, sizing, inspections, approvals, and permitting are the responsibilities of County Health Departments through their local authorized agents, but engineers and regional soil specialists are called upon for training, authorization, informal appeals, and consultation with Environmental Health Specialists. Enforcement of on-site wastewater rules and laws is the responsibility of the local environmental health specialists. For more information on State rules pertaining to site evaluations and soil suitability for septic systems see http://www.deh.enr.state.nc.us/osww_new/images/Rules/1900RulesJune2006.pdf. Septic Systems and Straight Piping With the increase in development there is an increase in demand for individual wastewater treatment systems requiring higher flows on smaller tracks of land. Wastewater from many households is not treated at wastewater treatment plants associated with NPDES discharge permits. Instead, it is treated on-site through the use of permitted septic systems. Poorly planned and/or maintained systems can fail and contribute to nonpoint source pollution. Wastewater from some of these homes illegally discharges directly to streams through what is known as a "straight pipe". In other cases, wastewater from failing septic systems makes its way to streams or contaminates groundwater. Straight piping and failing septic systems are illegal discharges of wastewater into waters of the State. With on-site septic systems, the septic tank unit treats some wastes and the drainfield provides further treatment and filtration of the pollutants and pathogens found in wastewater. A septic system that is operating properly does not discharge untreated wastewater to streams and lakes or to the ground’s surface where it can run into nearby surface waters. Septic systems are a safe and effective long-term method for treating wastewater if they are sited, sized and maintained properly. If the tank or drainfield are improperly located or constructed, or the systems are not 64 Stormwater and Wastewater Management maintained, nearby wells and surface waters may become contaminated, causing potential risks to human health. Septic tanks must be properly installed and maintained to ensure they function properly over the life of the system. Information about the proper installation and maintenance of septic tanks can be obtained by calling the environmental health sections of the local county health departments. See Appendix IV for contact information. The discharge of untreated or partially treated sewage can be extremely harmful to humans and the aquatic environment. Pollutants from illegally discharged household wastewater contain chemicals, nutrients, disease pathogens and endocrine disrupting chemicals. Although DWQ’s ambient monitoring of the waters in the Chowan River basin show a relatively small percentage of fecal coliform bacteria samples exceeding state standards for primary recreation, smaller streams may contain a higher concentration of bacteria and other pollutants. The economies of the counties in this basin are highly dependent upon river recreation, especially for tourists and seasonal residents. 2007 Recommendations In order to protect human health and maintain water quality, failing septic systems should be repaired, older systems must be updated, and straight pipes must be eliminated. Additional monitoring of fecal coliform bacteria throughout tributary watersheds will aid in identifying where straight pipes and failing septic systems are problems. Furthermore, precautions should be taken by local septic system permitting authorities to ensure that new systems are sited and constructed properly and that adequate repair area is also available. County, town and city planners need to understand the economic and human health ramifications caused by unsatisfactory septic systems and plan for long-term septic system sustainability. In areas where soils prevent individual septic systems a collective community septic system in appropriate soils may allow for sustainable development where a centralized sewer system is not available. Educational information should be provided to new septic system owners regarding the maintenance of these systems over time. For more information please see Chapter 9 in the Supplemental Guide to North Carolina’s Basinwide Planning: Support Document for Basinwide Water Quality Plans: http://www.ncwaterquality.org/basinwide/SupplementalGuide.htm. On-going on-site waste management activities in the Chowan Basin are led by the Albemarle Regional Health Services (ARHS), a district Board of Health for Bertie, Gates, Pasquotank, Perquimans, Camden, Tyrrell, and Washington counties, which conducts annual inspections on all 3,500 innovative and alternative systems. In addition, Chowan, Currituck, Hertford, and Martin counties contract with ARHS for their services. They follow-up on all on-site waste system repairs and are responsible for conventional systems within the 7-county district. DENR On-Site Wastewater System Management DENR has several initiatives related to on-site wastewater education, including current literature and scientific evaluation of potential pollutants from On-site Wastewater Systems. The DEH On-Site Wastewater Section has an active grant-seeking program. Current successful grants include those to the Wastewater Discharge Elimination (WaDE) program for eliminating straight pipes and failing systems, NPS coordinator grants for fate and transport of microbes in the shellfish areas, endocrine disrupting chemicals and pharmaceuticals, and an on-site management grant. The Division of Waste Management oversees the septage management firms and septage disposal in NC.