On April 18, 2007, the Federal Court Order (Consent Decree) negotiated between SD1, the US Environmental Protection Agency, and the Kentucky Energy and Environment Cabinet became effective. The purpose of the court order was to establish a structure for developing and implementing plans to address SD1's combined sewer overflows (CSOs) and sanitary sewer overflows (SSOs). Such overflows can degrade the quality of streams and rivers and are regulated through the federal Clean Water Act.
SD1's court order is unique because it incorporates a watershed-based approach in the planning process that allows for the consideration of pollution sources beyond sewer overflows. As required in the court order, SD1 has prepared Watershed Plans describing projects for addressing overflows and other water quality issues to be implemented over the next five years as well as a preliminary overall plan (i.e. full system solution) for achieving the goals of the order. Updated Watershed Plans will be submitted at five-year intervals. The deadline for full implementation of these Plans is December 31, 2025. Through this decree, SD1 will be managing the largest program of water quality improvement in Northern Kentucky's history.
Like many urban regions of the United States and Europe, the wastewater collection system of Northern Kentucky is comprised of both combined sewers and separate sanitary sewers. Combined sewers carry sewage and storm water runoff and are typically found in the older areas of cities such as Covington, Newport and Bellevue. During dry weather conditions, flow in SD1's combined sewer system is mostly comprised of sewage from homes and businesses and is conveyed to the Dry Creek Wastewater Treatment Plant. At the plant, wastewater is treated to remove pollutants before being discharged to the Ohio River.
During wet weather conditions, the capacity of the combined sewer system can be exceeded due to storm water runoff. As a result, excess flow is discharged from the system at CSO outfalls. The SD1 combined sewer system has 97 of these outfalls, the majority of which are located along the Ohio River, Licking River, Banklick Creek and Taylor Creek.
In more recently developed areas, a separate sanitary sewer system has been constructed to carry sanitary sewage and a separate storm water sewer network has been constructed to carry runoff. In properly functioning sanitary sewers, there is sufficient flow capacity in the system to convey all sewage to a treatment facility. In practice, separate sanitary sewers can be subject to additional flow during wet weather conditions. Increased wet weather flow in sanitary sewers can be caused by:
- Rain water inflow to the system from improper connections such as roof downspouts, driveway drains, etc.
- Rain water and ground water infiltration into aging manholes, pipes and private laterals.
This increased wet weather flow can create SSOs. SSOs can also result from the loss of flow capacity in the system (pipe blockages or collapse) or malfunctions at pump stations. There are 153 confirmed SSO points in the SD1 sanitary sewer system.
SD1's sanitary sewer service area encompasses 220 square miles of Campbell, Kenton and Boone Counties. The majority of this area is served by separate sanitary sewers.
In addition to CSOs and SSOs, there are other pollution sources that can impact the quality of Northern Kentucky's waterways. These sources include polluted runoff (urban and agricultural land use), failing septic systems and industrial point sources. The overall health of a waterway can also be affected by factors such as increased peak flows when land is converted from natural conditions to more developed uses, the loss of riparian buffers along stream corridors and the loss of wetlands.
SD1's Consent Decree is the country's first enforcement action that allows a community to use the watershed management approach to more efficiently and cost-effectively meet federal Clean Water Act requirements for addressing CSOs and SSOs. This approach is based on the fact that sewer overflows are not the sole source of impairment for Northern Kentucky's streams and rivers. Traditionally, most Consent Decrees focus solely on CSOs and SSOs, with an emphasis on gray infrastructure solutions. SD1's watershed approach identifies the characteristics of individual watersheds and considers CSOs and SSOs along with other sources impacting the waterways (such as runoff and dry weather sources). Additionally the iterative structure allows time to investigate new technologies and update the full system generalized plan using information gained from the implementation of projects during the first five years. SD1's watershed approach:
- Recognizes other pollutant sources and their relative impacts and puts CSOs and SSOs into context with those sources.
- Provides a process to address and control highest regional priorities first to offset controls on CSOs.
- Uses an integrated approach of controls that will address both wet and dry weather sources of pollution and lead to a greater improvement in water quality and public health.
- Provides additional benefits to the community such as air quality, wildlife habitat, urban beautification and economic development.
- Directs funds to projects that provide the greatest benefits.