Dissolved Aluminum, Total Iron and Total Manganese TMDLs TMDLs and source allocations were developed for impaired segments of tributaries in the Guyandotte watershed. A top-down methodology was followed to develop these TMDLs and allocate loads to sources. Headwaters were first analyzed, because their impact frequently had a profound effect on down-stream water quality. Loading contributions were reduced from applicable sources for these waterbodies and TMDLs were developed. Source reductions never resulted in loading contributions less than natural conditions represented by the undisturbed forest (Table 5-2). Model results from the selected successful scenarios were then routed through down-stream waterbodies. Therefore, when TMDLs were developed for down-stream impaired waterbodies, up-stream contributions were representing existing or unreduced conditions from unimpaired streams and reduced conditions from impaired streams. Using this method, contributions from all sources were weighted equitably. In some situations, reductions in sources impacting unlisted headwaters were required in order to meet downstream water quality criteria. In other situations, reductions in sources impacting impaired headwaters ultimately led to improvements down-stream. This effectually decreased required loading reductions from potential down-stream sources. The following general methodology was used when allocating to sources for the Guyandotte watershed TMDLs. C For watersheds with AMLs but no permitted point sources, AMLs were reduced first, until in-stream water quality criteria were met or to conditions no less than those of undisturbed forest. If further reductions were required, then the sediment sources (Harvested Forest, Burned Forest, Oil and Gas operations, and Roads) were reduced until water quality criteria were met. C For watersheds with AMLs and point sources, point sources were set at the precipitation induced load defined by the permit limits and AMLs were subsequently reduced. AMLs and revoked mining permits were reduced (point sources were not reduced) until in-stream water quality criteria were met, if possible. If further reduction was required once AMLs and revoked mines were reduced, sediment sources were then reduced. If even further reduction was required, the point source discharge limits were then reduced. C For watersheds where dissolved aluminum TMDLs were developed, source allocations for total iron and manganese were developed first since their total in-stream concentrations...
