SWS (TMDL subwatersheds)

Implementation of BMPs and load reductions must be reported at the subwatershed (SWS) scale.  Usually in the TMDL or watershed plan the targeted watersheds are divided into numerous SWS; each is assigned a number.  The image below shows how the Lambert Run watershed was divided.  The load reductions and BMPs are correlated to the sub-watershed (SWS) in which they are located.    
Watershed plans are tools to remediate nonpoint sources of pollution. They are usually developed following TMDLs. We encourage watershed groups and other stakeholders interested in developing watershes plans to keep the scale of the plan in mind; larger plans are often more difficult to implement and success can take much longer. At a minimum the plan should be no larger than a HUC12 size watershed.