Category 4b (TMDL Alternative)
Communities do not have to wait for a formal TMDL planning process. You can take the initiative to voluntarily create programs to clean up impaired waters. Because these programs are locally controlled, there is an opportunity to reduce overall costs and you can exert greater control over the cleanup process.
Impaired waters with pollution control programs in place that are expected to solve pollution problems (i.e., meet water quality standards) are commonly referred to as “Category 4b” waters because they are moved from Category 5 (impaired and needs TMDL) of the State’s Integrated Report to Category 4b (impaired but TMDL not required). While pollution control programs are not TMDLs, they must have many of the same features, and there must be some legal or financial assurance that they will be implemented.
A Category 4b demonstration allows DWR and EPA to formally recognize actions that, from a local perspective, provide a more appropriate and effective response to impairment than TMDL development. DWR has developed guidance for communities interested in developing a plan to address impaired waters. The guidance describes the elements required to qualify for Category 4b. Communities interested in pursuing this option should review the guidance document and plan to meet with DWR’s Modeling and Assessment Branch prior to development. Some communities may find that they are already meeting most if not all of the required elements.
Example TMDL Alternatives
McDowell Creek, Catawba River Basin
Mecklenburg County completed a watershed plan for McDowell Creek in 2006. The plan is a ‘comprehensive roadmap for the management and restoration of surface waters in the entire watershed.’ Category 4b was a relatively new option at the time this plan was developed, however DWR recognized that all of the elements required for a 4b demonstration were included in the plan. DWR was able to successfully recategorize McDowell Creek to 4b in 2008.
Little Alamance Creek, Cape Fear River Basin
In December 2010, the NC DWR requested public comment on the Draft Total Maximum Daily Load to Address Impaired Biological Integrity in the Little Alamance Creek Watershed, Alamance County, Cape Fear River Basin (Assessment Unit 16-19-11). The affected parties (Cities of Graham and Burlington and the NC DOT) requested the opportunity to address the impairment through development of an alternative TMDL plan that, when implemented, will allow for the achievement of the biological integrity standard in Little Alamance Creek.
EPA provided documentation supporting the 4B classification of Little Alamance Creek in January 2015. Information and watershed activities resulting from this project plan will be distributed through a public website (under development) hosted by the project partners.
Links: The City of Burlington is currently designing a project website to allow the public to follow the project.
Falls Lake, Neuse River Basin
Falls Lake was constructed by the U.S. Army Corps of Engineers in 1981 in order to provide flood control, drinking water supply, protection of downstream water quality, fish and wildlife conservation, and recreation.
Following questions in 2004 over the condition of Falls Lake, DWR began more intensive sampling for use support assessment. A Falls Lake Technical Advisory Committee (TAC) was formed in July 2005 to assist DWR with the review and modification of the monitoring strategy and developing levels of confidence for decision making associated with the monitoring and lake modeling activities. The field study was completed in fall 2007. Based on water quality data collected between 2002 and 2006, Falls Lake was listed as impaired for chlorophyll a on the draft NC 2008 303(d) list. The portion of the lake above I-85 was also listed as impaired for turbidity.
The Falls Lake Rules were adopted in January 2011 to acheive water quality standards in the lake by reducing the amount of pollution entering upstream. The rules are a staged nutrient management strategy designed to reduce nutrient discharges to the lake from various sources, including stormwater runoff from new and existing development, wastewater treatment plants and agriculture. Falls Lake was placed into category 4b in 2012.